Title of Invention	SELF-REGULATING EXHAUST GAS RECIRCULATION VALVE CONTROLLER UNIT
Abstract	1. A Self Regulating Exhaust Gas Recirculation valve Controller Unit for controlling Exhaust Gas Recirculation in an internal combustion engine which is not equipped with Air Sensor System and by detecting operating conditions of the engine through detection means, converting the operating conditions into digital quantities and electronically determining the control quantities for controlling a change-over between open and close position of an Exhaust Gas Recirculation valve of said internal combustion engine which comprises: (-) a means for moving the Exhaust Gas Recirculation valve between the closed position and open position, (-) a means for detecting the position of Exhaust Gas Recirculation valve and generating a position output signal, (-) a means for detecting engine temperature through water temperature sensor and generating a temperature output srgnal, (-) a means for detecting the speed of the engine and generating a speed output signal, (-) a means for detecting the load of the engine through throttle lever position and generating a load output signal and thereby throttle rate, (-) a means for processing operatively coupled to said moving means and said detecting means, said processing means receiving said output signals from said detecting means, processing the said output signals from said detecting means and thereafter transmitting position control signals to said moving means for moving the Exhaust Gas Recirculation valve, and (-) means for detecting malfunction of detecting means and Exhaust Gas Recirculation valve^ (-) said controller characterized in that means for detecting the throttle rate 'r~ :—— '-^—'i and using the throttle rate so measured in the feed back control loop through the Exhaust Gas Recirculation Controller to control the Exhaust Gas Recirculation.

Title of Invention

SELF-REGULATING EXHAUST GAS RECIRCULATION VALVE CONTROLLER UNIT

Abstract

1. A Self Regulating Exhaust Gas Recirculation valve Controller Unit for controlling Exhaust Gas Recirculation in an internal combustion engine which is not equipped with Air Sensor System and by detecting operating conditions of the engine through detection means, converting the operating conditions into digital quantities and electronically determining the control quantities for controlling a change-over between open and close position of an Exhaust Gas Recirculation valve of said internal combustion engine which comprises: (-) a means for moving the Exhaust Gas Recirculation valve between the closed position and open position, (-) a means for detecting the position of Exhaust Gas Recirculation valve and generating a position output signal, (-) a means for detecting engine temperature through water temperature sensor and generating a temperature output srgnal, (-) a means for detecting the speed of the engine and generating a speed output signal, (-) a means for detecting the load of the engine through throttle lever position and generating a load output signal and thereby throttle rate, (-) a means for processing operatively coupled to said moving means and said detecting means, said processing means receiving said output signals from said detecting means, processing the said output signals from said detecting means and thereafter transmitting position control signals to said moving means for moving the Exhaust Gas Recirculation valve, and (-) means for detecting malfunction of detecting means and Exhaust Gas Recirculation valve^ (-) said controller characterized in that means for detecting the throttle rate 'r~ :—— '-^—'i and using the throttle rate so measured in the feed back control loop through the Exhaust Gas Recirculation Controller to control the Exhaust Gas Recirculation.

Full Text	The invention relates to Self Regulating Exhaust Gas Recirculation Valve Controller Unit for an internal combustion engine and also a method of controlling the engine wherein the Exhaust Gas Recirculation Valve is electronically actuated and thereby provides accurate positioning of Exhaust gas recirculation valve by determining the Exhaust gas recirculation rates. PRIOR ART In view of increasing stringency of emission control regulation, it is desired to improve fuel supply systems of engines to reduce noxious exhaust emissions while maintaining good engine drivability. The formation of oxides of nitrogen is associated with high temperature within combustion chamber. Under high temperature, there is little free oxygen to participate in the formation of oxides of nitrogen. Therefore the rate of formation of oxides of nitrogen is greatest with mixtures containing some excess air under high temperature. Formation of oxides of nitrogen is reduced if the peak temperature during combustion is reduced by diluting the mixture with exhaust gas. Thus, either the air/fuel ratio or the amount of the exhaust gas recirculated must be maintained above a particular minimum value to keep the generation of oxides of nitrogen within an acceptable level. But it is also necessary to keep the air/fuel ratio, or when the exhaust gas is recirculated, the recirculation rate of exhaust gas below a particular level beyond which engine roughness or emissions of unburned hydro carbons become unacceptable. In the present Exhaust Gas Recirculation hence forth termed as "EXHAUST GAS RECIRCUI-ATION" valve Controller unit as per the invention, the Self Regulating Exhaust Gas Recirculation is electronically actuated, and provides for high speed, accurate response to varying engine loads. The Controller provides a precise determination of optimum Exhaust Gas Recirculation rates and precise positioning of Exhaust Gas Recirculation Valve. Thereby the engine can respond with rated power over its range of operating conditions and undesirable effects of black smoke and/or engine stalling due to introduction of too much recirculated exhaust gas, which is a common problem in the prior art is eliminated here. Also air mass sensor no longer controls the EGR and thereby eliminating the AMS means a simpler constructions and cost effectiveness has been adiieved. OBJECT OF THE INVENTION It is an object of this invention to provide a new or improved Exhaust Gas Recirculation controller system for an internal combustion engine and also a method of controlling such an engine. The controller which as a function of predetermined criteria, causes a changeover of the operation of engine. Sensor systems communicate the signals to the processor and the processor monitors and manages the parameters necessary for changeover. The prior arts rely on monitoring the air intake by the engine to control the EGR valve. The air intake is measured by Air Mass Sensors. The first object of this invention is to eliminate Air Mass Sensor which is complicated and expensive. Further prior arts do not measure the throttle valve in the feed back for control loop. The second object of this invention to achieve a better acceleration response, which in the invention is achieved by measuring the throttle valve and to monitor the acceleration mode. DESCRIPTION OF THE INVENTION It is thereby to be understood, exhaust gases mixed with the intake air reduce the amount of oxygen in the fresh intake charge while increasing its specific heat. Both factors result in a lower combustion temperature. This decreases the occurrences of oxides of Nitrogen (NOX) and therefore reduced exhaust emissions. However excess Exhaust Gas Recirculation will result in increased particulates or soot due to air deficiency. The quantity of Exhaust Gas Recirculation must therefore be controlled to ensure that the combustion chamber receives sufficient oxygen to support combustion. Exhaust gas is recirculated into the intal Generally an Self Regulating Exhaust Gas Recirculation valve can be controlled in two ways :- (1) On/off control : The Exhaust Gas Recirculation valve is either switched ON or OFF by a micro-switch mounted on the throttle lever. (2) Progressive control ; The Exhaust Gas Recirculation valve opening is dynamically varied based on current engine operating conditions. Generally lookup tables are stored in Read Only Memory these days but are not adequate to overcome the emission & efficiency problem as there are too many variables to be considered. Various closed-loop systems are also in use these days. The closed-loop system uses an exhaust gas oxygen sensor. When exhaust gas is recirculated by this means, an oxygen sensor cannot and will not compensate far errors in the accuracy of the equipment responsible for the recirculation. The Self Regulating Exhaust Gas Recirculation valve controller unit as per the invention monitors the operating conditions of the diesel engine by means of sensors located on the engine. Based on the Input signals monitored It calculates the amount of exhaust gas required to be recirculated. With the inputs given into it, it dynamically varies the opening of the Exhaust Gas Recirculation valve by controlling an electro-pneumatic actuator. The Sensor means on engine is for generating output signals representative of operating conditions of the engine in response to which said processor carries out plurality of job, and wherein said one of the selected ones of the said jobs programs comprises a program for coupling data representative of Output signals generated by said sensor means to said processor. One of the programs also comprises of a program for determining the duty cycle for controlling the fuel air ratio for said engine. The controller for an Self Regulating Exhaust Gas Recirculation valve as per the invention includes actuator for moving the Exhaust Gas Recirculation valve between a closed position, an open position and a position sensor for detecting the position of the Exhaust Gas Recirculation valve and generating a position output signal, and sensor means for detecting the operating conditions of an engine. A processing circuit receives the output signals from sensors and transmits control signal to activate the actuator and thereby move the Exhaust Gas Recirculation valve. The hardware features of the Self Regulating Exhaust Gas Recirculation valve controller unit as per the invention includes :- 8bit RISC microcontroller On board power supply regulator On board analog signal conditioner 3 I^OSFET 2.5A current power stages In-circuit Flash programming facility Serial transmission for remote diagnostics Very compact PCB (6Qmm x 39mm) Blink codes for diagnostics Sealed unit and IP54 compliant The software features of the Self Regulating Exhaust Gas Recirculation valve controller unit as per the invention includes :- Measurement, linearization and calculation of Coolant temperature sensor Throttle lever position sensor Exhaust Gas Recirculation valve lift sensor Engine speed from Generator W terminal Exhaust Gas Recirculation rate calculation based on engine speed and throttle using 3 dimensional interpolation Acceleration detection by measuring rate of change of throttle Temperature compensation and correction of Exhaust Gas Recirculation rate Closed loop position control of Exhaust Gas Recirculation valve using position feedback Diagnostic interface to analyse online performance of controller Built-in safety functions The inputs and outputs of the Self Regulating Exhaust Gas Recirculation valve controller unit as per the invention is :- Engine temperature through the water temperature sensor. Engine Speed. Engine load through the throttle lever position. Exhaust Gas Recirculation valve lift through the valve position sensor. Electro-pneumatic pressure modulator. Cold start solenoid actuator. In the Self Regulating Exhaust Gas Recirculation controller unit as per the invention, the amount of fuel supply to the engine is corrected in accordance with the condition of the exhaust gas, and the difference between the fuel control signal derived from a prior operation condition and the engine condition. The process of detection and correction is as follows :- The following are the mandatory inputs required for the effective functioning of the Exhaust Gas Recirculation controller: 1. Engine Speed This is one of the vital parameters of the engine because the Exhaust Gas Recirculation rate required at any specific speed is different for a particular load condition. Such rate required is established after repeated trial of the engine/vehicle in order to get optimum performance and lower exhaust emissions. The engine speed is the number of revolutions the engine crankshaft makes in one minute. This can be measured by mounting specific sensor on the engine to generate a known rate of electrical pulses which is given as input to the Exhaust Gas Recirculation controtler. Alternately, the pulses produced by the alternator mounted on the engine, available through its 'W terminal can be given as the input. In such case an additional fixed factor of the speed ratio between the engine and the alternator also need to be programmed in the Exhaust Gas Recirculation controller. 2. Throttle Position The Throttle position sensor is mounted on the fuel injection pump whose fuel control lever is mechanically linked to the accelerator pedal of the vehicle. When the driver of the vehicle presses the accelerator pedal, the fuel control lever is actuated which in turn actuates the potentiometric sensor. The sensor gives proportional voltage signal output to the Exhaust Gas Recirculation controller, which calculates the throttle rate. 3. Temperature sensor The temperature sensor is a thermistor based sensor mounted on the engine so that the sensor is In contact with the engine cooling liquid (water/coolant). The Exhaust Gas Recirculation controller measures the voltage drop at the sensor and performs linearisation and calculates the corresponding temperature value. Using the values of engine speed and the throttle rate, which is the current operating condition of the engine, the Exhaust Gas Recirculation controller retrieves appropriate Exhaust Gas Recirculation rate values from a table of values programmed in the Exhaust Gas Recirculation controller. TTie controller then performs interpolation of retrieved values to obtain the correct Exhaust Gas Recirculation rate for the specific operating condition of the engine. From the Exhaust Gas Recirculation rate calculated, the appropriate power for the pressure modulator is provided by the Exhaust Gas Recirculation controller in order to create suitable vacuum level which is necessary to operate the Exhaust Gas Recirculation valve to obtain the calculated Exhaust Gas Recirculation rate. The controlled vacuum so modulated by the pressure modulator is then given to the Exhaust Gas Recirculation valve, which operates to the lever according to the vacuum received by it. The Self Regulating Exhaust Gas Recirculation controller checks if the temperature Is In the safe operating range of the engine. The Exhaust Gas Recirculation controller closes the Exhaust Gas Recirculation valve fully if the temperature value is outside the safe range of the engine in order to prevent the engine from the bad effects of Exhaust Gas Recirculation at high temperatures. The Exhaust Gas Recirculation rate can also be modified as per the invention in order to obtain fine Exhaust Gas Recirculation optimization based on temperature. BRIEF DESCRIPTION OF THE DRAWING: Figl: Control flow diagram of the Controller illustrate the Exhaust Gas Recirculation rate calculation based on engine, speed and throttle using 3D Interpolation and these modification of Exhaust Gas Recirculation rate further based on the temperature to achieve resultant Exhaust Gas Recirculation rate value. Fig2 : illustrates the sequence of temperature sensing by means of temperature sensor, conversion of analog to digital value which is fed to the processor. Fig3: illustrates the sequence of throttle position sensing which is proportional to accelerator pedal position by means of potentiometers sensor, conversion of analog to digital value which is fed to the Controller. Fig4: illustrates the sequence of Exhaust Gas Recirculation valve position sensing by means of a potentiometers sensor, analog value converted to digital value and fed to the Controller. FigS: illustrates the sequence of speed sensing by means of an alternator using alternator to engine speed factor, which Is then fed to the Controller. Fig6: illustrates the sequence of illustrates the conversion of resultant Exhaust Gas Recirculation rate value to PWM duty cycle which is fed to the Controller. Fig7: illustrates the sequence of the Pressure Modular which receives Air, Vacuum and also the PWM duty cycle value from Exhaust Gas Recirculation controller, thereby mixing air and vacuum depending on the PWM duty cycle value from Exhaust Gas Recirculation Controller to give out a controlled vacuum. Fig 8; illustrates the sequence of closed loop control circuit of Exhaust Gas Recirculation Pressure Modulator, Exhaust Gas Recirculation valve and the Exhaust Gas Recirculation controller, wherein depending on actual Exhaust Gas Recirculation rate being higher or lower than required Exhaust Gas Recirculation rate, Exhaust Gas Recirculation controller will reduce or increase correspondingly and ther^y the PWM power to Pressure Modular is also changed accordingly. The changed PWM power causes a change in controller vacuum to Exhaust Gas Recirculation valve which is turn responds. The correction is continuous to maintain the desired Exhaust Gas Recirculation rate. WORKING OF THE INVENTION In the Self Regulating Exhaust Gas Recirculation controller unit as per the invention, the Exhaust Gas Recirculation Valve which is a control valve for taking out a portion of exhaust gas burnt in the cylinders of engine and exhausted to the atmosphere through the exhaust pipe and also for recirculating it to the suction pipe by an Exhaust Gas Recirculation pipe connected to Exhaust Gas Recirculation valve is 'controlled'. The recirculation of exhaust gas is effected to improve exhaust gas emissions. The recirculation ratio of the exhaust gas is controlled by Exhaust Gas Recirculation valve and an electro - pneumatic actuator controls the Exhaust Gas Recirculation valve. By controlling the electro-pneumatic actuator, the opening of the Exhaust Gas Recirculation is dynamically varied. The data necessary for the engine control are supplied to the controller unit so that the engine is controlled by a control instruction from the controller unit. The Controller issues instructions for selectively receiving a multiplicity of external information necessary for the control of the operation and also executes arithmetic operation in accordance with stored system control program in the Controller and the various data and contents accessed and transmitted through input-output device. As per the selection commands, multiplicity of information signals from external device is gathered in analog information, thereafter converting analog information into digital information and through a control circuit applying the digital information to the controller to cause it to execute arithmetic operation in accordance with the contents stored in the memory and providing control signals to the external control unit. Basically air to fuel ratio is controlled by the arithmetic operation of the Controller. The Exhaust Gas Recirculation as per the invention relates to a process of electronically controlling the operation of Exhaust Gas Recirculation valve provided with a controller system which includes sensors for detecting operating conditions of engine and Exhaust Gas, and a processor comprising of an arithmetic unit for arithmetically determining control quantities for controlling said Exhaust Gas Recirculation valve through the Digital processing of output signals produced from said sensors, memory means for storing therein programs and data for performing said arithmetic operations and control means for controlling said Exhaust Gas Recirculation valve on the basis of the results of said arithmetic Operations, wherein contents of said arithmetic operations are divided into a number of jobs independence on control functions to be performed, said process comprising of various functions in the Exhaust Gas Recirculation Controller unit. The Detail description of the functioning of the Self Regulating Exhaust Gas Recirculation controller is described below : 1. The Self Regulating Exhaust Gas Recirculation controller as per the invention is switched on when the ignition key of the vehicle is turned ON. The battery supply is switched to the Exhaust Gas Recirculation controller. The Exhaust Gas Recirculation controller works effectively when the battery voltage is within the range of 8 volts to 16 volts. Adequate filters are provided to remove the unwanted spikes in the voltage. A voltage regulator further regulates the voltage to required level for other sections of the hardware to function normally. The regulated voltage is then supplied to various sensors for excitation, which are discussed later. 2. Once sufficient voltage is available to the Microcontroller, the crystal starts generating the clock frequency that is required for Microcontroller operation. The Microcontroller starts executing of the programmed software when the clock pulses stabilizes. The Exhaust Gas Recirculation controller execution is described below. 3. The Self Regulating Exhaust Gas Recirculation controller first initializes all the input and output ports as per the requirement for measurement and control. It also initializes the timer modules which is required for timing functions, the Analog to Digital Converter module for Analog to Digital conversion and the Pulse Width Modulator module for power control. 4. The Self Regulating Exhaust Gas Recirculation controller measures analog voltage signal, which is in inverse proportion to the temperature of the engine using the temperature sensor that is mounted on the engine. The measured analog voltage is then converted to digital value using Analog to Digital converter module. The digital value so converted is then checked for legitimacy and only the correct digital value is then converted to temperature value using the proportionality factors and constants. The value so calculated is then stored in memory. The sequence is illustrated in Fig-2 as a flow chart figure. 5. The Self Regulating Exhaust Gas Recirculation controller measures analog voltage signal, which is proportional to the accelerator pedal position, also called as the throttle position, of the vehicle using the potentiometric sensor, mounted on the fuel injection pump of the vehicle. The measured analog voltage is then converted to digital value using Analog to Digital Converter module. The digital value so converted is then checked for legitimacy and only the correct digital value is then converted to throttle value using the proportionality factors and constants. The value so calculated is then stored in memory. The sequence is illustrated in Fig-3 as a flow chart. 6. The Self Regulating Exhaust Gas Recirculation controller measures analog voltage signal, which Is proportional to the Exhaust Gas Recirculation valve position from the potentiometric sensor of the Exhaust Gas Recirculation valve. The measured analog voltage is then converted to digital value using Analog to Digital Converter module. The digital value so converted is then checked for legitimacy and only the correct digital value is then converted to Exhaust Gas Recirculation valve lift value using the proportionality factors and constants. The value so calculated is then stored in memory. The sequence is Illustrated in Fig-4 as a flow chart. 7. The Self Regulating Exhaust Gas Recirculation controller is given pulse input from the "W terminal of the alternator mounted on the engine. The frequency of the pulse input is proportional to the speed of the alternator. The alternator speed Is at a fixed proportion to that of the speed of the engine. The Exhaust Gas Recirculation controller calculates the time period of the input pulse. The frequency of the input pulse and hence the engine speed is then calculated using the alternator to engine speed factor and other constants. T>ie calculated engine speed in revolutions per minute is then stored in memory. The sequence is illustrated in Fig-5 as flow chart. Exhaust Gas Recirculation Rate Calculation is now described in relation to the software flow diagram illustrated as Rg-l. The sequence of step is described below: 1. The Self Regulating Exhaust Gas Recirculation controller checks the difference between the previous throttle value, which is available after completion of one loop of all modules, and the current measured throttle value. The difference is estimated and if there is an increase in throttle value over the previous measured value and if the difference is above a set minimum value, then the Exhaust Gas Recirculation controller registers the condition as the vehicle is in acceleration mode. This is the process for detection of acceleration. 2. When the Self Regulating Exhaust Gas Recirculation controller registers an accelerating condition of the vehicle, the Exhaust Gas Recirculation controller closes the Exhaust Gas Recirculation valve fully. This closing of Exhaust Gas Recirculation valve is achieved by reducing the PWM duty cycle to minimum value thereby reducing the power to the pressure modulator. The pressure modulator in turn will reduce the vacuum available to the Exhaust Gas Recirculation valve. 3. Exhaust Gas Recirculation rate calculation is the next task the controller does. With the measured values of throttle and engine speed, the controller check with the Exhaust Gas Recirculation rate table and extracts two different values each of throttle, speed and Exhaust Gas Recirculation rate and performs a three dimensional interpolation of the data extracted. The interpolated data so calculated is stored in memory. 4. The Self Regulating Exhaust Gas Recirculation controller then performs tasks that are temperature dependent. Depending on the temperature value calculated in the present cycle, the Exhaust Gas Recirculation controller makes modifications on the calculated Exhaust Gas Recirculation rate. Then the Exhaust Gas Recirculation rate corrections are carried out as per the required rate. 5. After the Exhaust Gas Recirculation rate undergoes corrections, the resultant Exhaust Gas Recirculation rate value is then converted to PWM duty cycle value using proportionality factors and constants. The so calculated duty cycle value is then stored in memory. 6. The stored PWM duty cycle value is then loaded on to the two designated memory locations from which the PWM module will retrieve the duty cycle value and control the duty cycle as per the retrieved data of the PWM duty cycle. 7. The PWM module then switches the output port according to the PWM period and the PWM duty cycle, which provides a PWM controlled input signal. The output signal is then used for switching the power to the pressure Modulator. The power switching is done using a suitable switching device that can handle the switching currents of the pressure modulator. The sequence is illustrated in Rg - 6 as a flow chart. 8. In the Self Regulating Exhaust Gas Recirculation Controller unit as per the invention, the Pressure Modulator is mounted on the vehicle. The vacuum generated from the vacuum pump mounted on the engine is connected to the Pressure Modulator through a reservoir. The Pressure Modulator also has atmospheric air as input. Depending on the input power the Pressure Modulator receives from the Exhaust Gas Recirculation controller the Pressure Modulator mixes air and vacuum and gives out a controlled vacuum from its output port. The sequence is illustrated as flow chart in Fig - 7. 9. In the Self Regulating Exhaust Gas Recirculation Controller unit as per the invention, the controlled vacuum, which is the output of the Pressure Modulator, is connected to Exhaust Gas Recirculation valve that is mounted on the engine. Depending on the controlled vacuum that is available to the Exhaust Gas Recirculation valve, the valve opens its port, which allows part of the exhaust gas from the exhaust manifold to flow back into the engine. "Hie amount of opening of the Exhaust Gas Recirculation valve port is estimated, from the feedback that is connected to the Exhaust Gas Recirculation controller, by the Exhaust Gas Recirculation controller. As per the invention, in the Self Regulating Exhaust Gas Recirculation Controller unit, the sensors for throttle position could be a separate sensor mounted for estimating the throttle lever position or a throttle potentiometer mounted on the fuel injection pump of the vehicle. Similarily, the engine speed sensor could be a stand-alone sensor sensing the fly wheel speed of the engine or input from the *W' terminal of the alternator could be used by estimating the speed ratio between the alternator and the engine. As per the invention, in the Self Regulating Exhaust Gas Recirculation Controller unit, the close loop function logic is also implemented (whose activation \s optional depending on the requirement). The Exhatst Gas Reorodation controller after estimating the required Exhaust Gas Recirculation rate generates the required PWM power to the pressure modulator, which in turn gives controlled vacuum to the Exhaust Gas Recirculation valve. The Exhaust Gas Recirculation valve opens depending on the vacuum it receives from the pressure modid^or. A feed back of Exhaust Gas Redrculation valve lift is given to the Exhaust Gas Recirculation controller from the pt^sntkHnetbrc feedback sensor that is on the Exhaust Gas Redrculation vah/e. The Exhaust Gas Redrculation controller then estimates the achial Exhaust Gas Redrculation valve rate. The Exhaust Gas Redrculation controller then cakrulates the difference b^ween the Exhaust Gas Recirculation rate reqwred and actual Exhaust Gas RedrodatkHt rate. Depending on the actual Exhaust Gas Redrculation rate being higher or lower than the rec^iired Exhaust Gas Redrct^atnn rate, the Exhaust Gas Recvctriation controller now reduces or increases respectively, the PWM power to the pressure modulator. This changed PWM power causes a change in vacuum to the Exhaust Gas Recirculation vatve which in turn responds as required. This correction is continuously done to maintain the required Exhaust Gas Recirculation rate. The sequence is illustrated as flow chart in Fig-8. An Self Regulating Exhaust Gas Recirculation Controller Unit for controlling Exhaust Gas Recirculation in an internal combustion engine by detecting operating conditions of the engine through detection means, converting the operating conditions into digital quantities and electronically determining the control quantities for controlling a change-over between open and close position of an ^ Exhaust Gas Recirculation valve of said internal combustion engine which includes: (-) a means for moving the Exhaust Gas Recirculation valve between the closed position and open position; cv; (-) a means for detecting the position of Exhaust Gas Recirculation valve and generating a position output signal; (-) a means for detecting engine temperature through water temperature sensor and generating a temperature output signal; (-) a means for detecting the speed of the engine and generating a speed output signal; (-) a means for detecting the load of the engine through throttle lever position and generating a load output signal and thereby generate throttle rate; (-) a means for processing operatively coupled to said moving means and said detecting means, said processing means receiving said output signals from said detecting means, processing the said output signals from said detecting means and thereafter transmitting position control signals to said moving means for moving the Exhaust Gas Recirculation valve; and (-) a means for detecting malfunction of detecting means and Exhaust Gas Recirculation valve. An Self Regulating Exhaust Gas Recirculation Controller Unit for controlting Exhaust Gas Recirculation in an internal combustion engine, in which a means for processing is configured for processing output signals from said detecting means, to generate position control output signals to said moving means for setting the position at which Exhaust Gas Recirculation valve is open, rnduding:- (-) An arithmetic unit for arithmetically determining control quantities for controlling said engine through the digital processing of output signals from said detectors; (-) a memory unit for storing therein programs, maps and data for performing said arithmetic operations; and (-) a control unit for controlling said engine on the basis of the results of said arithmetic operations, wherein contents of said arithmetic operations are generated to obtain position control input signal to be fed into moving means. An Self Regulating Exhaust Gas Recirculation Controller Unit for controlling Exhaust Gas Recirculation in an internal combustion engine, a means for processing is a processor configured for processing output signals from said detecting means to generate position control input signal to be fed into said moving means for setting the position at which Exhaust Gas Recirculation valve is open which comprises of: (-) processing in arithmetic unit the load output signal and speed output signal from said detecting means to develop two actual Exhaust Gas Recirculation rates, signals from all the said detecting means are processed with the aid of data stored in memory unit to develop a desired Exhaust Gas Recirculation rate and thereafter further processing to develop a Exhaust Gas Recircuiation rate difference signal, which is stored in memory unit; (-) processing in arithmetic unit the position output signal from said detecting means to develop the actual position of Exhaust Gas Recirculation valve, signals from all the said detecting means are processed with the aid of data stored in memory unit to develop a desired position of Exhaust Gas Recirculation valve and thereafter further processing to develop a position difference signal, which is stored in memory unit; and (-) processing in arithmetic unit the Exhaust Gas Recirculation rate difference signal and position difference signal to develop the position control input signal which is fed to the moving means. An Self Regulating Exhaust Gas Recirculation Controller Unit for controlling Exhaust Gas Recirculation in an internal combustion engine, wherein a means for moving includes an electro-pneumatic pressure modulated actuator for controlling the movement of the valve corresponding to the current signal transmitted through the actuator which is dependent on the position control input signal received from the said processor. An Self Regulating Exhaust Gas Recirculation Controller Unit for controlling Exhaust Gas Recirculation in an internal combustion engine, which is configure with logic built-in diagnostics for monitoring output signal received from detecting means and detection of malfunction of detecting means and Exhaust Gas Recirculation by means of blink codes generated by driving lamp output. MAIN FEATURES OF SELF REGULATING EXHAUST GAS RECIRCULATION CONTROLLER AS PER THE INVENTION IS GIVEN BELOW :- A. The Self Regulating Exhaust Gas Recirculation valve controller unit as per the invention comprises of: (-) An Electro-pneumatic actuator for moving the Exhaust Gas Recirculation valve between a closed position and an open position ; (-) A position sensor means for detecting the position of Exhaust Gas Recirculation valve & generating a position output signal ; {-) A temperature sensor means for detecting the engine temperature through water temperature sensor and generating a temperature output signal ; (-) A speed sensor means for detecting the engine speed and generating a speed output signal ; (-) A Load sensor means for detecting the engine load through the throttle lever position and generating a load output signal ; and (-) A processing circuit coupled to said actuator and said sensors, said processing circuit, receiving said output signals from said sensors and transmitting control signal to said electro-pneumatic actuator & thereby moving the Exhaust Gas Recirculation valve correspondingly. B. An Exhaust Gas Recirculation valve controller unit as per the Invention comprises of :- (-) a means for moving the Exhaust Gas Recirculation valve between the closed position and open position ; (') a means for detecting the position of Exhaust Gas Recirculation valve and generating a position output signal ; (-) a means for detecting the engine temperature through water temperature sensor and generating a temperature output signal ; (-) a means for detecting the speed of the engine and generating a speed output signal ; (-) a means for detecting the load of the engine through throttle lever position and generating a load output signal ; and (-) a means for processing, coupled to said moving means and said detecting means, said processing means receiving said output signals from said detecting means and transmitting signals to said moving means for moving the Exhaust Gas Recirculation valve; C. A method for controlling the actuator of Self Regulating Exhaust Gas Recirculation valve controller unit as per the invention comprises the steps of :- [-) Detecting the position of Exhaust Gas Recirculation valve ; -) Detecting the engine temperature ; -) Detecting the engine speed ; -) Detecting the engine load ; -) Receiving the output signals from detecting means into processing means ; -) Processing the signals received in the processing means ; -) Transmitting signals to actuator; [') Changeover of valve position accordingly. Advantages of the Self Regulating Exhaust Gas Recirculation controller unit as per the invention is :- -) Low cost Highly compact in size Flexibility Immediate solution for part electronic emission requirements In-built safety and diagnosis Reduction in HC + NOX emissions of approximately 10 to 25% Safeguarding of engines at high engine speeds and loads (-) Dynamic calculation of Exhaust Gas Recirculation resulting in efficient emission optimisation The above description and accompanying drawings are merely illustrative of the application of the principles of the present invention and are not limiting. Numerous other arrangements which embody the principles of the invention and which fall within its spirit and scope may be readily devised by those skilled in the art. Accordingly the invention is not limited by the foregoing description, but is only limited by the scope of the claims. WE CLAIM : 1. A Self Regulating Exhaust Gas Recirculation valve Controller Unit for controlling Exhaust Gas Recirculation in an internal combustion engine which is not equipped with Air Sensor System and by detecting operating conditions of the engine through detection means, converting the operating conditions into digital quantities and electronically determining the control quantities for controlling a change-over between open and close position of an Exhaust Gas Recirculation valve of said internal combustion engine which comprises: (-) a means for moving the Exhaust Gas Recirculation valve between the closed position and open position, (-) a means for detecting the position of Exhaust Gas Recirculation valve and generating a position output signal, (-) a means for detecting engine temperature through water temperature sensor and generating a temperature output srgnal, (-) a means for detecting the speed of the engine and generating a speed output signal, (-) a means for detecting the load of the engine through throttle lever position and generating a load output signal and thereby throttle rate, (-) a means for processing operatively coupled to said moving means and said detecting means, said processing means receiving said output signals from said detecting means, processing the said output signals from said detecting means and thereafter transmitting position control signals to said moving means for moving the Exhaust Gas Recirculation valve, and (-) means for detecting malfunction of detecting means and Exhaust Gas Recirculation valve^ (-) said controller characterized in that means for detecting the throttle rate 'r~ :—— '-^—'i and using the throttle rate so measured in the feed back control loop through the Exhaust Gas Recirculation Controller to control the Exhaust Gas Recirculation. 2. A Self Regulating Exhaust Gas Recirculation Controller Unit for controlling Exhaust Gas Recirculation in an internal combustion engine as claimed in claim 1, in which a means for processing is configured for processing output signals from said detecting means, to generate position control output signals to said moving means for setting the position at which Exhaust Gas Recirculation valve is open, comprises: (-) an arithmetic unit for arithmetically determining control quantities for controlling said engine through the digital processing of output signals from said detectors, (-) a memory unit for storing therein programs, maps and data for performing said arithmetic operations, and (-) a control unit for controlling said engine on the basis of the results of said arithmetic operations, wherein contents of said arithmetic operations are generated to obtain position control input signal to be fed into moving means. 3. A Self Regulating Exhaust Gas Recirculation Controller Unit for controlling Exhaust Gas Recirculation in an internal combustion engine as claimed in claim 1, a means for processing is a processor configured for processing output signals from said detecting means to generate position control input signal to be fed into said moving means for setting the position at which Exhaust Gas Recirculation valve Is open which comprises of : (-] processing In arithmetic unit the load output signal and speed output signal from said detecting means to develop two actual Exhaust Gas Recirculation rates, signals from all the said detecting means are processed with the aid of data stored in memory unit to develop a desired Exhaust Gas Recirculation rate and thereafter further processing to develop a Exhaust Gas Recirculation rate difference signal, which is stored In memory unit, (-) processing in arithmetic unit the position output signal from said detecting means to develop the actual position of Exhaust Gas Recirculation valve, signals from all the said detecting means are processed with the aid of data stored in memory unit to develop a desired position of Exhaust Gas Recirculation valve and thereafter further processing to develop a position difference signal, which is stored in memory unit, and (-) processing in arithmetic unit the Exhaust Gas Recirculation rate difference signal and position difference signal to develop the position control input signal which is fed to the moving means. 4. A Self Regulating Exhaust Gas Recirculation Controller Unit for controlling Exhaust Gas Recirculation in an internal combustion engine as claimed in claim 1, wherein a means for moving comprises an electro-pneumatic pressure modulated actuator for controlling the movement of the valve corresponding to the current signal transmitted through the actuator which is dependent on the position control input signal received from the said processor. 5. A Self Regulating Exhaust Gas Recirculation Controller Unit for controlling Exhaust Gas Recirculation in an internal combustion engine as claimed in claim 1, which is configure with logic built-in diagnostics for monitoring output signal received from detecting means and detection of malfunction of detecting means and Exhaust Gas Recirculation by means of blink codes generated by driving tamp output.

Full Text

The invention relates to Self Regulating Exhaust Gas Recirculation Valve Controller Unit for an internal combustion engine and also a method of controlling the engine wherein the Exhaust Gas Recirculation Valve is electronically actuated and thereby provides accurate positioning of Exhaust gas recirculation valve by determining the Exhaust gas recirculation rates.
PRIOR ART
In view of increasing stringency of emission control regulation, it is desired to improve fuel supply systems of engines to reduce noxious exhaust emissions while maintaining good engine drivability.
The formation of oxides of nitrogen is associated with high temperature within combustion chamber. Under high temperature, there is little free oxygen to participate in the formation of oxides of nitrogen. Therefore the rate of formation of oxides of nitrogen is greatest with mixtures containing some excess air under high temperature. Formation of oxides of nitrogen is reduced if the peak temperature during combustion is reduced by diluting the mixture with exhaust gas.
Thus, either the air/fuel ratio or the amount of the exhaust gas recirculated must be maintained above a particular minimum value to keep the generation of oxides of nitrogen within an acceptable level. But it is also necessary to keep the air/fuel ratio, or when the exhaust gas is recirculated, the recirculation rate of exhaust gas below a particular level beyond which engine roughness or emissions of unburned hydro carbons become unacceptable.
In the present Exhaust Gas Recirculation hence forth termed as "EXHAUST GAS RECIRCUI-ATION" valve Controller unit as per the invention, the Self Regulating Exhaust Gas Recirculation is electronically actuated, and provides for high speed, accurate response to varying engine loads. The Controller provides

a precise determination of optimum Exhaust Gas Recirculation rates and precise positioning of Exhaust Gas Recirculation Valve. Thereby the engine can respond with rated power over its range of operating conditions and undesirable effects of black smoke and/or engine stalling due to introduction of too much recirculated exhaust gas, which is a common problem in the prior art is eliminated here. Also air mass sensor no longer controls the EGR and thereby eliminating the AMS means a simpler constructions and cost effectiveness has been adiieved.
OBJECT OF THE INVENTION
It is an object of this invention to provide a new or improved Exhaust Gas Recirculation controller system for an internal combustion engine and also a method of controlling such an engine. The controller which as a function of predetermined criteria, causes a changeover of the operation of engine. Sensor systems communicate the signals to the processor and the processor monitors and manages the parameters necessary for changeover.
The prior arts rely on monitoring the air intake by the engine to control the EGR valve. The air intake is measured by Air Mass Sensors. The first object of this invention is to eliminate Air Mass Sensor which is complicated and expensive. Further prior arts do not measure the throttle valve in the feed back for control loop. The second object of this invention to achieve a better acceleration response, which in the invention is achieved by measuring the throttle valve and to monitor the acceleration mode.
DESCRIPTION OF THE INVENTION
It is thereby to be understood, exhaust gases mixed with the intake air reduce the amount of oxygen in the fresh intake charge while increasing its specific heat. Both factors result in a lower combustion temperature. This decreases the occurrences of oxides of Nitrogen (NOX) and therefore reduced exhaust emissions.

However excess Exhaust Gas Recirculation will result in increased particulates or soot due to air deficiency. The quantity of Exhaust Gas Recirculation must therefore be controlled to ensure that the combustion chamber receives sufficient oxygen to support combustion. Exhaust gas is recirculated into the intal Generally an Self Regulating Exhaust Gas Recirculation valve can be controlled in two ways :-
(1) On/off control : The Exhaust Gas Recirculation valve is either switched ON or OFF by a micro-switch mounted on the throttle lever.
(2) Progressive control ; The Exhaust Gas Recirculation valve opening is dynamically varied based on current engine operating conditions.
Generally lookup tables are stored in Read Only Memory these days but are not adequate to overcome the emission & efficiency problem as there are too many variables to be considered. Various closed-loop systems are also in use these days. The closed-loop system uses an exhaust gas oxygen sensor. When exhaust gas is recirculated by this means, an oxygen sensor cannot and will not compensate far errors in the accuracy of the equipment responsible for the recirculation.
The Self Regulating Exhaust Gas Recirculation valve controller unit as per the invention monitors the operating conditions of the diesel engine by means of sensors located on the engine. Based on the Input signals monitored It calculates the amount of exhaust gas required to be recirculated. With the inputs given into it, it dynamically varies the opening of the Exhaust Gas Recirculation valve by controlling an electro-pneumatic actuator.

The Sensor means on engine is for generating output signals representative of operating conditions of the engine in response to which said processor carries out plurality of job, and wherein said one of the selected ones of the said jobs programs comprises a program for coupling data representative of Output signals generated by said sensor means to said processor. One of the programs also comprises of a program for determining the duty cycle for controlling the fuel air ratio for said engine.
The controller for an Self Regulating Exhaust Gas Recirculation valve as per the invention includes actuator for moving the Exhaust Gas Recirculation valve between a closed position, an open position and a position sensor for detecting the position of the Exhaust Gas Recirculation valve and generating a position output signal, and sensor means for detecting the operating conditions of an engine. A processing circuit receives the output signals from sensors and transmits control signal to activate the actuator and thereby move the Exhaust Gas Recirculation valve.
The hardware features of the Self Regulating Exhaust Gas Recirculation valve controller unit as per the invention includes :-
8bit RISC microcontroller
On board power supply regulator
On board analog signal conditioner
3 I^OSFET 2.5A current power stages
In-circuit Flash programming facility
Serial transmission for remote diagnostics
Very compact PCB (6Qmm x 39mm)
Blink codes for diagnostics
Sealed unit and IP54 compliant

The software features of the Self Regulating Exhaust Gas Recirculation valve controller unit as per the invention includes :-
Measurement, linearization and calculation of
Coolant temperature sensor
Throttle lever position sensor
Exhaust Gas Recirculation valve lift sensor
Engine speed from Generator W terminal
Exhaust Gas Recirculation rate calculation based on engine speed and
throttle using 3 dimensional interpolation
Acceleration detection by measuring rate of change of throttle
Temperature compensation and correction of Exhaust Gas Recirculation rate
Closed loop position control of Exhaust Gas Recirculation valve using position
feedback
Diagnostic interface to analyse online performance of controller
Built-in safety functions
The inputs and outputs of the Self Regulating Exhaust Gas Recirculation valve controller unit as per the invention is :-
Engine temperature through the water temperature sensor.
Engine Speed.
Engine load through the throttle lever position.
Exhaust Gas Recirculation valve lift through the valve position sensor.
Electro-pneumatic pressure modulator.
Cold start solenoid actuator.
In the Self Regulating Exhaust Gas Recirculation controller unit as per the invention, the amount of fuel supply to the engine is corrected in accordance with the condition of the exhaust gas, and the difference between the fuel control signal derived from a prior operation condition and the engine condition.

The process of detection and correction is as follows :-
The following are the mandatory inputs required for the effective functioning of the Exhaust Gas Recirculation controller:
1. Engine Speed
This is one of the vital parameters of the engine because the Exhaust Gas Recirculation rate required at any specific speed is different for a particular load condition. Such rate required is established after repeated trial of the engine/vehicle in order to get optimum performance and lower exhaust emissions.
The engine speed is the number of revolutions the engine crankshaft makes in one minute. This can be measured by mounting specific sensor on the engine to generate a known rate of electrical pulses which is given as input to the Exhaust Gas Recirculation controtler. Alternately, the pulses produced by the alternator mounted on the engine, available through its 'W terminal can be given as the input. In such case an additional fixed factor of the speed ratio between the engine and the alternator also need to be programmed in the Exhaust Gas Recirculation controller.
2. Throttle Position
The Throttle position sensor is mounted on the fuel injection pump whose fuel control lever is mechanically linked to the accelerator pedal of the vehicle. When the driver of the vehicle presses the accelerator pedal, the fuel control lever is actuated which in turn actuates the potentiometric sensor. The sensor gives proportional voltage signal output to the Exhaust Gas Recirculation controller, which calculates the throttle rate.
3. Temperature sensor
The temperature sensor is a thermistor based sensor mounted on the engine so that the sensor is In contact with the engine cooling liquid (water/coolant). The

Exhaust Gas Recirculation controller measures the voltage drop at the sensor and performs linearisation and calculates the corresponding temperature value.
Using the values of engine speed and the throttle rate, which is the current operating condition of the engine, the Exhaust Gas Recirculation controller retrieves appropriate Exhaust Gas Recirculation rate values from a table of values programmed in the Exhaust Gas Recirculation controller. TTie controller then performs interpolation of retrieved values to obtain the correct Exhaust Gas Recirculation rate for the specific operating condition of the engine.
From the Exhaust Gas Recirculation rate calculated, the appropriate power for the pressure modulator is provided by the Exhaust Gas Recirculation controller in order to create suitable vacuum level which is necessary to operate the Exhaust Gas Recirculation valve to obtain the calculated Exhaust Gas Recirculation rate.
The controlled vacuum so modulated by the pressure modulator is then given to the Exhaust Gas Recirculation valve, which operates to the lever according to the vacuum received by it.
The Self Regulating Exhaust Gas Recirculation controller checks if the temperature Is In the safe operating range of the engine. The Exhaust Gas Recirculation controller closes the Exhaust Gas Recirculation valve fully if the temperature value is outside the safe range of the engine in order to prevent the engine from the bad effects of Exhaust Gas Recirculation at high temperatures. The Exhaust Gas Recirculation rate can also be modified as per the invention in order to obtain fine Exhaust Gas Recirculation optimization based on temperature.
BRIEF DESCRIPTION OF THE DRAWING:
Figl: Control flow diagram of the Controller illustrate the Exhaust Gas Recirculation rate calculation based on engine, speed and throttle using 3D Interpolation and these modification of Exhaust Gas Recirculation rate further based on the temperature to achieve resultant Exhaust Gas Recirculation rate value.

Fig2 : illustrates the sequence of temperature sensing by means of temperature sensor, conversion of analog to digital value which is fed to the processor.
Fig3: illustrates the sequence of throttle position sensing which is proportional to accelerator pedal position by means of potentiometers sensor, conversion of analog to digital value which is fed to the Controller.
Fig4: illustrates the sequence of Exhaust Gas Recirculation valve position sensing by means of a potentiometers sensor, analog value converted to digital value and fed to the Controller.
FigS: illustrates the sequence of speed sensing by means of an alternator using alternator to engine speed factor, which Is then fed to the Controller.
Fig6: illustrates the sequence of illustrates the conversion of resultant Exhaust Gas Recirculation rate value to PWM duty cycle which is fed to the Controller.
Fig7: illustrates the sequence of the Pressure Modular which receives Air, Vacuum and also the PWM duty cycle value from Exhaust Gas Recirculation controller, thereby mixing air and vacuum depending on the PWM duty cycle value from Exhaust Gas Recirculation Controller to give out a controlled vacuum.
Fig 8; illustrates the sequence of closed loop control circuit of Exhaust Gas Recirculation Pressure Modulator, Exhaust Gas Recirculation valve and the Exhaust Gas Recirculation controller, wherein depending on actual Exhaust Gas Recirculation rate being higher or lower than required Exhaust Gas Recirculation rate, Exhaust Gas Recirculation controller will reduce or increase correspondingly and ther^y the PWM power to Pressure Modular is also changed accordingly. The changed PWM power causes a change in controller vacuum to Exhaust Gas Recirculation valve which is turn responds. The correction is continuous to maintain the desired Exhaust Gas Recirculation rate.

WORKING OF THE INVENTION
In the Self Regulating Exhaust Gas Recirculation controller unit as per the invention, the Exhaust Gas Recirculation Valve which is a control valve for taking out a portion of exhaust gas burnt in the cylinders of engine and exhausted to the atmosphere through the exhaust pipe and also for recirculating it to the suction pipe by an Exhaust Gas Recirculation pipe connected to Exhaust Gas Recirculation valve is 'controlled'. The recirculation of exhaust gas is effected to improve exhaust gas emissions. The recirculation ratio of the exhaust gas is controlled by Exhaust Gas Recirculation valve and an electro - pneumatic actuator controls the Exhaust Gas Recirculation valve. By controlling the electro-pneumatic actuator, the opening of the Exhaust Gas Recirculation is dynamically varied. The data necessary for the engine control are supplied to the controller unit so that the engine is controlled by a control instruction from the controller unit.
The Controller issues instructions for selectively receiving a multiplicity of external information necessary for the control of the operation and also executes arithmetic operation in accordance with stored system control program in the Controller and the various data and contents accessed and transmitted through input-output device. As per the selection commands, multiplicity of information signals from external device is gathered in analog information, thereafter converting analog information into digital information and through a control circuit applying the digital information to the controller to cause it to execute arithmetic operation in accordance with the contents stored in the memory and providing control signals to the external control unit.
Basically air to fuel ratio is controlled by the arithmetic operation of the Controller.
The Exhaust Gas Recirculation as per the invention relates to a process of electronically controlling the operation of Exhaust Gas Recirculation valve provided with a controller system which includes sensors for detecting operating conditions of engine and Exhaust Gas, and a processor comprising of an arithmetic unit for

arithmetically determining control quantities for controlling said Exhaust Gas Recirculation valve through the Digital processing of output signals produced from said sensors, memory means for storing therein programs and data for performing said arithmetic operations and control means for controlling said Exhaust Gas Recirculation valve on the basis of the results of said arithmetic Operations, wherein contents of said arithmetic operations are divided into a number of jobs independence on control functions to be performed, said process comprising of various functions in the Exhaust Gas Recirculation Controller unit.
The Detail description of the functioning of the Self Regulating Exhaust Gas Recirculation controller is described below :
1. The Self Regulating Exhaust Gas Recirculation controller as per the invention is switched on when the ignition key of the vehicle is turned ON. The battery supply is switched to the Exhaust Gas Recirculation controller. The Exhaust Gas Recirculation controller works effectively when the battery voltage is within the range of 8 volts to 16 volts. Adequate filters are provided to remove the unwanted spikes in the voltage. A voltage regulator further regulates the voltage to required level for other sections of the hardware to function normally. The regulated voltage is then supplied to various sensors for excitation, which are discussed later.
2. Once sufficient voltage is available to the Microcontroller, the crystal starts generating the clock frequency that is required for Microcontroller operation. The Microcontroller starts executing of the programmed software when the clock pulses stabilizes. The Exhaust Gas Recirculation controller execution is described below.
3. The Self Regulating Exhaust Gas Recirculation controller first initializes all the input and output ports as per the requirement for measurement and control. It also initializes the timer modules which is required for timing functions, the Analog to Digital Converter module for Analog to Digital conversion and the Pulse Width Modulator module for power control.

4. The Self Regulating Exhaust Gas Recirculation controller measures analog voltage signal, which is in inverse proportion to the temperature of the engine using the temperature sensor that is mounted on the engine. The measured analog voltage is then converted to digital value using Analog to Digital converter module. The digital value so converted is then checked for legitimacy and only the correct digital value is then converted to temperature value using the proportionality factors and constants. The value so calculated is then stored in memory. The sequence is illustrated in Fig-2 as a flow chart figure.
5. The Self Regulating Exhaust Gas Recirculation controller measures analog voltage signal, which is proportional to the accelerator pedal position, also called as the throttle position, of the vehicle using the potentiometric sensor, mounted on the fuel injection pump of the vehicle. The measured analog voltage is then converted to digital value using Analog to Digital Converter module. The digital value so converted is then checked for legitimacy and only the correct digital value is then converted to throttle value using the proportionality factors and constants. The value so calculated is then stored in memory. The sequence is illustrated in Fig-3 as a flow chart.
6. The Self Regulating Exhaust Gas Recirculation controller measures analog voltage signal, which Is proportional to the Exhaust Gas Recirculation valve position from the potentiometric sensor of the Exhaust Gas Recirculation valve. The measured analog voltage is then converted to digital value using Analog to Digital Converter module. The digital value so converted is then checked for legitimacy and only the correct digital value is then converted to Exhaust Gas Recirculation valve lift value using the proportionality factors and constants. The value so calculated is then stored in memory. The sequence is Illustrated in Fig-4 as a flow chart.
7. The Self Regulating Exhaust Gas Recirculation controller is given pulse input from the "W terminal of the alternator mounted on the engine. The frequency of the pulse input is proportional to the speed of the alternator. The alternator speed Is at a fixed proportion to that of the speed of the engine. The Exhaust Gas

Recirculation controller calculates the time period of the input pulse. The frequency of the input pulse and hence the engine speed is then calculated using the alternator to engine speed factor and other constants. T>ie calculated engine speed in revolutions per minute is then stored in memory. The sequence is illustrated in Fig-5 as flow chart.
Exhaust Gas Recirculation Rate Calculation is now described in relation to the software flow diagram illustrated as Rg-l. The sequence of step is described below:
1. The Self Regulating Exhaust Gas Recirculation controller checks the difference between the previous throttle value, which is available after completion of one loop of all modules, and the current measured throttle value. The difference is estimated and if there is an increase in throttle value over the previous measured value and if the difference is above a set minimum value, then the Exhaust Gas Recirculation controller registers the condition as the vehicle is in acceleration mode. This is the process for detection of acceleration.
2. When the Self Regulating Exhaust Gas Recirculation controller registers an accelerating condition of the vehicle, the Exhaust Gas Recirculation controller closes the Exhaust Gas Recirculation valve fully. This closing of Exhaust Gas Recirculation valve is achieved by reducing the PWM duty cycle to minimum value thereby reducing the power to the pressure modulator. The pressure modulator in turn will reduce the vacuum available to the Exhaust Gas Recirculation valve.
3. Exhaust Gas Recirculation rate calculation is the next task the controller does. With the measured values of throttle and engine speed, the controller check with the Exhaust Gas Recirculation rate table and extracts two different values each of throttle, speed and Exhaust Gas Recirculation rate and performs a three dimensional interpolation of the data extracted. The interpolated data so calculated is stored in memory.

4. The Self Regulating Exhaust Gas Recirculation controller then performs tasks that are temperature dependent. Depending on the temperature value calculated in the present cycle, the Exhaust Gas Recirculation controller makes modifications on the calculated Exhaust Gas Recirculation rate. Then the Exhaust Gas Recirculation rate corrections are carried out as per the required rate.
5. After the Exhaust Gas Recirculation rate undergoes corrections, the resultant Exhaust Gas Recirculation rate value is then converted to PWM duty cycle value using proportionality factors and constants. The so calculated duty cycle value is then stored in memory.
6. The stored PWM duty cycle value is then loaded on to the two designated memory locations from which the PWM module will retrieve the duty cycle value and control the duty cycle as per the retrieved data of the PWM duty cycle.
7. The PWM module then switches the output port according to the PWM period and the PWM duty cycle, which provides a PWM controlled input signal. The output signal is then used for switching the power to the pressure Modulator. The power switching is done using a suitable switching device that can handle the switching currents of the pressure modulator. The sequence is illustrated in Rg - 6 as a flow chart.
8. In the Self Regulating Exhaust Gas Recirculation Controller unit as per the invention, the Pressure Modulator is mounted on the vehicle. The vacuum generated from the vacuum pump mounted on the engine is connected to the Pressure Modulator through a reservoir. The Pressure Modulator also has atmospheric air as input. Depending on the input power the Pressure Modulator receives from the Exhaust Gas Recirculation controller the Pressure Modulator mixes air and vacuum and gives out a controlled vacuum from its output port. The sequence is illustrated as flow chart in Fig - 7.
9. In the Self Regulating Exhaust Gas Recirculation Controller unit as per the invention, the controlled vacuum, which is the output of the Pressure Modulator, is

connected to Exhaust Gas Recirculation valve that is mounted on the engine. Depending on the controlled vacuum that is available to the Exhaust Gas Recirculation valve, the valve opens its port, which allows part of the exhaust gas from the exhaust manifold to flow back into the engine. "Hie amount of opening of the Exhaust Gas Recirculation valve port is estimated, from the feedback that is connected to the Exhaust Gas Recirculation controller, by the Exhaust Gas Recirculation controller.
As per the invention, in the Self Regulating Exhaust Gas Recirculation Controller unit, the sensors for throttle position could be a separate sensor mounted for estimating the throttle lever position or a throttle potentiometer mounted on the fuel injection pump of the vehicle.
Similarily, the engine speed sensor could be a stand-alone sensor sensing the fly wheel speed of the engine or input from the *W' terminal of the alternator could be used by estimating the speed ratio between the alternator and the engine.
As per the invention, in the Self Regulating Exhaust Gas Recirculation Controller unit, the close loop function logic is also implemented (whose activation \s optional depending on the requirement). The Exhatst Gas Reorodation controller after estimating the required Exhaust Gas Recirculation rate generates the required PWM power to the pressure modulator, which in turn gives controlled vacuum to the Exhaust Gas Recirculation valve. The Exhaust Gas Recirculation valve opens depending on the vacuum it receives from the pressure modid^or. A feed back of Exhaust Gas Redrculation valve lift is given to the Exhaust Gas Recirculation controller from the pt^sntkHnetbrc feedback sensor that is on the Exhaust Gas Redrculation vah/e. The Exhaust Gas Redrculation controller then estimates the achial Exhaust Gas Redrculation valve rate. The Exhaust Gas Redrculation controller then cakrulates the difference b^ween the Exhaust Gas Recirculation rate reqwred and actual Exhaust Gas RedrodatkHt rate.
Depending on the actual Exhaust Gas Redrculation rate being higher or lower than the rec^iired Exhaust Gas Redrct^atnn rate, the Exhaust Gas Recvctriation

controller now reduces or increases respectively, the PWM power to the pressure modulator. This changed PWM power causes a change in vacuum to the Exhaust Gas Recirculation vatve which in turn responds as required. This correction is continuously done to maintain the required Exhaust Gas Recirculation rate. The sequence is illustrated as flow chart in Fig-8.
An Self Regulating Exhaust Gas Recirculation Controller Unit for controlling Exhaust Gas Recirculation in an internal combustion engine by detecting operating conditions of the engine through detection means, converting the operating conditions into digital quantities and electronically determining the control quantities for controlling a change-over between open and close position of an ^ Exhaust Gas Recirculation valve of said internal combustion engine which includes:
(-) a means for moving the Exhaust Gas Recirculation valve between the closed position and open position;
cv; (-) a means for detecting the position of Exhaust Gas Recirculation valve
and generating a position output signal;
(-) a means for detecting engine temperature through water temperature sensor and generating a temperature output signal;
(-) a means for detecting the speed of the engine and generating a speed output signal;
(-) a means for detecting the load of the engine through throttle lever position and generating a load output signal and thereby generate throttle rate;
(-) a means for processing operatively coupled to said moving means and said detecting means, said processing means receiving said output signals from said detecting means, processing the said output signals from said detecting means and thereafter transmitting position control signals to said moving means for moving the Exhaust Gas Recirculation valve; and

(-) a means for detecting malfunction of detecting means and Exhaust Gas Recirculation valve.
An Self Regulating Exhaust Gas Recirculation Controller Unit for controlting Exhaust Gas Recirculation in an internal combustion engine, in which a means for processing is configured for processing output signals from said detecting means, to generate position control output signals to said moving means for setting the position at which Exhaust Gas Recirculation valve is open, rnduding:-
(-) An arithmetic unit for arithmetically determining control quantities for controlling said engine through the digital processing of output signals from said detectors;
(-) a memory unit for storing therein programs, maps and data for performing said arithmetic operations; and
(-) a control unit for controlling said engine on the basis of the results of said arithmetic operations, wherein contents of said arithmetic operations are generated to obtain position control input signal to be fed into moving means.
An Self Regulating Exhaust Gas Recirculation Controller Unit for controlling Exhaust Gas Recirculation in an internal combustion engine, a means for processing is a processor configured for processing output signals from said detecting means to generate position control input signal to be fed into said moving means for setting the position at which Exhaust Gas Recirculation valve is open which comprises of:
(-) processing in arithmetic unit the load output signal and speed output signal from said detecting means to develop two actual Exhaust Gas Recirculation rates, signals from all the said detecting means are processed with the aid of data stored in memory unit to develop a desired Exhaust Gas Recirculation rate and thereafter further processing to develop a Exhaust Gas Recircuiation rate difference signal, which is stored in memory unit;

(-) processing in arithmetic unit the position output signal from said detecting means to develop the actual position of Exhaust Gas Recirculation valve, signals from all the said detecting means are processed with the aid of data stored in memory unit to develop a desired position of Exhaust Gas Recirculation valve and thereafter further processing to develop a position difference signal, which is stored in memory unit; and
(-) processing in arithmetic unit the Exhaust Gas Recirculation rate difference signal and position difference signal to develop the position control input signal which is fed to the moving means.
An Self Regulating Exhaust Gas Recirculation Controller Unit for controlling Exhaust Gas Recirculation in an internal combustion engine, wherein a means for moving includes an electro-pneumatic pressure modulated actuator for controlling the movement of the valve corresponding to the current signal transmitted through the actuator which is dependent on the position control input signal received from the said processor.
An Self Regulating Exhaust Gas Recirculation Controller Unit for controlling Exhaust Gas Recirculation in an internal combustion engine, which is configure with logic built-in diagnostics for monitoring output signal received from detecting means and detection of malfunction of detecting means and Exhaust Gas Recirculation by means of blink codes generated by driving lamp output.
MAIN FEATURES OF SELF REGULATING EXHAUST GAS RECIRCULATION CONTROLLER AS PER THE INVENTION IS GIVEN BELOW :-
A. The Self Regulating Exhaust Gas Recirculation valve controller unit as per the invention comprises of:
(-) An Electro-pneumatic actuator for moving the Exhaust Gas Recirculation valve between a closed position and an open position ;

(-) A position sensor means for detecting the position of Exhaust Gas Recirculation valve & generating a position output signal ;
{-) A temperature sensor means for detecting the engine temperature through water temperature sensor and generating a temperature output signal ;
(-) A speed sensor means for detecting the engine speed and generating a speed output signal ;
(-) A Load sensor means for detecting the engine load through the throttle lever position and generating a load output signal ; and
(-) A processing circuit coupled to said actuator and said sensors, said processing circuit, receiving said output signals from said sensors and transmitting control signal to said electro-pneumatic actuator & thereby moving the Exhaust Gas Recirculation valve correspondingly.
B. An Exhaust Gas Recirculation valve controller unit as per the Invention comprises of :-
(-) a means for moving the Exhaust Gas Recirculation valve between the closed position and open position ;
(') a means for detecting the position of Exhaust Gas Recirculation valve and generating a position output signal ;
(-) a means for detecting the engine temperature through water temperature sensor and generating a temperature output signal ;
(-) a means for detecting the speed of the engine and generating a speed output signal ;
(-) a means for detecting the load of the engine through throttle lever position and generating a load output signal ; and
(-) a means for processing, coupled to said moving means and said detecting means, said processing means receiving said output signals from said detecting

means and transmitting signals to said moving means for moving the Exhaust Gas Recirculation valve;
C. A method for controlling the actuator of Self Regulating Exhaust Gas Recirculation valve controller unit as per the invention comprises the steps of :-
[-) Detecting the position of Exhaust Gas Recirculation valve ;
-) Detecting the engine temperature ;
-) Detecting the engine speed ;
-) Detecting the engine load ;
-) Receiving the output signals from detecting means into processing
means ;
-) Processing the signals received in the processing means ; -) Transmitting signals to actuator; [') Changeover of valve position accordingly.
Advantages of the Self Regulating Exhaust Gas Recirculation controller unit as per the invention is :-
-) Low cost
Highly compact in size
Flexibility
Immediate solution for part electronic emission requirements
In-built safety and diagnosis
Reduction in HC + NOX emissions of approximately 10 to 25%
Safeguarding of engines at high engine speeds and loads

(-) Dynamic calculation of Exhaust Gas Recirculation resulting in efficient emission optimisation
The above description and accompanying drawings are merely illustrative of the application of the principles of the present invention and are not limiting. Numerous other arrangements which embody the principles of the invention and which fall within its spirit and scope may be readily devised by those skilled in the art. Accordingly the invention is not limited by the foregoing description, but is only limited by the scope of the claims.

WE CLAIM :
1. A Self Regulating Exhaust Gas Recirculation valve Controller Unit for controlling Exhaust Gas Recirculation in an internal combustion engine which is not equipped with Air Sensor System and by detecting operating conditions of the engine through detection means, converting the operating conditions into digital quantities and electronically determining the control quantities for controlling a change-over between open and close position of an Exhaust Gas Recirculation valve of said internal combustion engine which comprises:
(-) a means for moving the Exhaust Gas Recirculation valve between the closed position and open position,
(-) a means for detecting the position of Exhaust Gas Recirculation valve and generating a position output signal,
(-) a means for detecting engine temperature through water temperature sensor and generating a temperature output srgnal,
(-) a means for detecting the speed of the engine and generating a speed output signal,
(-) a means for detecting the load of the engine through throttle lever position and generating a load output signal and thereby throttle rate,
(-) a means for processing operatively coupled to said moving means and said detecting means, said processing means receiving said output signals from said detecting means, processing the said output signals from said detecting means and thereafter transmitting position control signals to said moving means for moving the Exhaust Gas Recirculation valve, and
(-) means for detecting malfunction of detecting means and Exhaust Gas
Recirculation valve^
(-) said controller characterized in that means for detecting the throttle
rate 'r~ :—— '-^—'i and using the throttle rate so measured in the feed
back control loop through the Exhaust Gas Recirculation Controller to control the Exhaust Gas Recirculation.

2. A Self Regulating Exhaust Gas Recirculation Controller Unit for controlling
Exhaust Gas Recirculation in an internal combustion engine as claimed in claim 1, in
which a means for processing is configured for processing output signals from said
detecting means, to generate position control output signals to said moving means
for setting the position at which Exhaust Gas Recirculation valve is open,
comprises:
(-) an arithmetic unit for arithmetically determining control quantities for controlling said engine through the digital processing of output signals from said detectors,
(-) a memory unit for storing therein programs, maps and data for performing said arithmetic operations, and
(-) a control unit for controlling said engine on the basis of the results of said arithmetic operations, wherein contents of said arithmetic operations are generated to obtain position control input signal to be fed into moving means.
3. A Self Regulating Exhaust Gas Recirculation Controller Unit for controlling
Exhaust Gas Recirculation in an internal combustion engine as claimed in claim 1, a
means for processing is a processor configured for processing output signals from
said detecting means to generate position control input signal to be fed into said
moving means for setting the position at which Exhaust Gas Recirculation valve Is
open which comprises of :
(-] processing In arithmetic unit the load output signal and speed output signal from said detecting means to develop two actual Exhaust Gas Recirculation rates, signals from all the said detecting means are processed with the aid of data stored in memory unit to develop a desired Exhaust Gas Recirculation rate and thereafter further processing to develop a Exhaust Gas Recirculation rate difference signal, which is stored In memory unit,
(-) processing in arithmetic unit the position output signal from said detecting means to develop the actual position of Exhaust Gas Recirculation valve, signals from all the said detecting means are processed with the aid of data stored

in memory unit to develop a desired position of Exhaust Gas Recirculation valve and thereafter further processing to develop a position difference signal, which is stored in memory unit, and
(-) processing in arithmetic unit the Exhaust Gas Recirculation rate difference signal and position difference signal to develop the position control input signal which is fed to the moving means.
4. A Self Regulating Exhaust Gas Recirculation Controller Unit for controlling
Exhaust Gas Recirculation in an internal combustion engine as claimed in claim 1,
wherein a means for moving comprises an electro-pneumatic pressure modulated
actuator for controlling the movement of the valve corresponding to the current
signal transmitted through the actuator which is dependent on the position control
input signal received from the said processor.
5. A Self Regulating Exhaust Gas Recirculation Controller Unit for controlling
Exhaust Gas Recirculation in an internal combustion engine as claimed in claim 1,
which is configure with logic built-in diagnostics for monitoring output signal
received from detecting means and detection of malfunction of detecting means
and Exhaust Gas Recirculation by means of blink codes generated by driving tamp
output.

Documents:

683-mas-2002 abstract duplicate.pdf

683-mas-2002 abstract.pdf

683-mas-2002 claims duplicate.pdf

683-mas-2002 claims.pdf

683-mas-2002 correspondence others.pdf

683-mas-2002 correspondence po.pdf

683-mas-2002 description (complete) duplicate.pdf

683-mas-2002 description (complete).pdf

683-mas-2002 drawings duplicate.pdf

683-mas-2002 drawings.pdf

683-mas-2002 form-1.pdf

683-mas-2002 form-10.pdf

683-mas-2002 form-26.pdf

683-mas-2002 form-3.pdf

683-mas-2002 form-5.pdf

683-mas-2002 form-6.pdf

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Patent Number

198721

Indian Patent Application Number

683/MAS/2002

PG Journal Number

08/2007

Publication Date

23-Feb-2007

Grant Date

24-Jan-2006

Date of Filing

16-Sep-2002

Name of Patentee

MOTOR INDUSTRIES COMPANY LIMITED

Applicant Address

HOSUR ROAD, ADUGODI, BANAGALORE 560 030

Inventors:

#	Inventor's Name	Inventor's Address
1	UMESH THAMPAN	NENO.906, MICO LAYOUT, HONGASANDRA, BEGUR ROAD, BANGALORE - 560 068
2	MAHESH BABU SUBRAMANIAN	FLAT NO 10, BAGYAVANTI APARTMENTS, PARIJET NAGAR, NASHIK - 422 005

PCT International Classification Number

F02D21/08

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA