Title of Invention

A SYSTEM AND METHOD FOR MONITORING LIQUID PILFERAGE

Abstract

Liquids stored in large quantities need to be monitored periodically for leakage and pilferage. This invention provides a system and method for monitoring the liquid pilferage from any storage medium such as fuel tanks, oil bunkers, water tanks etc. This system comprises a liquid level sensor for sensing the level of liquid in the medium. A processing means for processing said liquid level signal is provided to make the signal received to be usable for computation. The processing means has a signal conditioning means that conditions the signal and removes any transients that may occur, A computing means for computing the information received from said sensor is provided The computing means has an analog to digital converter; said computing means is configured to relay signal to a display unit for displaying the date, time and amount of liquid pilfered. (FIG 1)

Full Text

This invention relates to a novel system and method for monitoring liquid pilferage from any storage medium such as fuel tanks, oil bunkers, water tanks etc. BACKGROUND OF THE INVENTION Liquids are stored in large quantities in storage mediums and seldom are their quantities being monitored for leakage or pilferage or any other fraud or discrepancies. Regular monitoring of liquid stock should be logged into the database to check for these errors. For instance, with the fuel price always on the increase, many truck drivers take out fuel from the tank and sell it and blame the mileage of the vehicle for its low performance. In order to minimize or even eliminate such fraud and pilferage a system and method for monitoring liquid levels and liquid consumption rate is necessary for cutting down costs and preventing losses due to mismanagement of such resources. SUMMARY OF THE INVENTION The object of the present invention is to provide a system and method for monitoring liquid pilferage and recording and displaying such information on computers to allow a complete analysis of the liquid being stored. The liquid level parameter is fed as input signals and a micro controller processes and computes these signals to display the various custom made data that the user needs to have in his possession according to his requirement. For instance, in a vehicle the micro controller could compute and display the basic vehicle performance data such as average mileage per liter, maximum distance that can be traveled with the existing fuel, total distance traveled, fuel pilfered quantity with time and date etc. These data could be displayed in a cyclic manner by known means and the data displayed could be changed using a toggle switch. This novel system is made tamper proof by providing the facility of liquid monitoring even during the absence of power supply. In case of lack of power supply the system records the liquid level and stores in permanent memory EEPROM. Whenever power supply is restored again, it gives information about the pilferage/leakage immediately if any. If any of the sensor wire is cut, display gives information about the same as an Error message. This novel system also has an external port through which all the data can be downloaded to the desktop computer for specified duration through serial communication. The data like Liquid pilferage is stored in non-volatile memory EEPROM and can be downloaded and printed in specified format for the future records. The detailed description of such a liquid monitoring system and method as applied to a vehicle is given below wherein the fuel level in the fuel tank is monitored and the display provides information such as average mileage per liter, maximum distance that can be traveled with the existing fuel, total distance traveled, fuel pilfered quantity with time and date etc. The system always resides in one of its three modes viz. active mode; sleep mode and battery backup mode. The system resides in the active mode whenever the vehicle engine is running or whenever the toggle switch is operated. In the active mode the input signals such as fuel level and vehicle speed is processed and based on them data such as odometer, trip meter, average mileage per liter and distance to empty are computed and displayed. Further, critical data such as Fuel level and odometer value are backed up periodically in the active mode to prevent their loss owing to removal of battery supply. The system is in the sleep mode when the engine is not running. The main task performed in this state is fuel pilferage monitoring. If a pilferage is detected the pilfered quantity with date and time will be stored in the storage media, preferably in the EEPROM. In the sleep mode, the toggle switch scanning is continuously performed. However the display, preferably an LED display, will be switched off in this mode. In the battery backup mode only the Real Time Clock (RTC) can function. A backup battery is provided to supply power to the RTC in the absence of the vehicle battery power. DETAILED DESCRIPTION OF THE INVENTION The hardware architecture of this system for processing the input parameters and carrying out the required computations has been designed to fully meet the requirements and the specifications of the system. The input signals such as engine speed signal, vehicle speed signal and fuel level sensor signal are suitably processed and then fed to the micro controller for carrying out the required computations. The vehicle battery voltage is 24V DC, which is scaled down and fed to one of the Analog Digital Converters (ADC) inputs for monitoring battery voltage. In addition, a RTC with battery backup has been included in the hardware. Key inputs are provided for setting the RTC values. A serial EEPROM is provided to store odometer value, fuel level, KMPL and fuel pilferage information. The hardware incorporates a 7 digit seven segment LED for displaying the various parameters. Optionally, two lamps are provided for indicating the engine RPM range to the user. The analog input signal of the range between 0 to 5.22 V is received from the fuel level sensor. This input signal is processed and scaled down to 0 to 4.3V before being fed to the ADC of the micro controller. This ADC output is used internally for computing parameters such as KMPL, distance to empty and fuel pilferage. The fuel level sensor input signal is scaled down from 0-5.22V to 0-4.3V through a resistor divider and then fed to the ADC. Additionally, a diode (4. 7V) and a capacitor will be provided at this input pin to suppress any transients that arise in this pin. The analog supply voltage will be fed with 5V and reference voltage pin will be fed with 4.3V. The ADC has a precision of 19mV. Hence, minimum change in the fuel level that can be detected is 0.9 liters. Since the ADC precision is much higher than the precision of the fuel level sensor (3 liters), no errors will be introduced by micro controller ADC. The fuel level input signal is an analog signal from the fuel sensor that indicates the quantity of fuel available in the tank. The ADC output provides the digital value corresponding to the fuel quantity. This fuel value is utilized in the required computations for monitoring the usage of fuel at a given time. Once every 10 kilometers, the average fuel value is stored in a cyclic buffer. Critical cases are also taken care in this computation. Each time, when the vehicle is started, checks for events like re- fuelling or pilferage will be done and suitable actions will be carried out in the software. In addition, if the difference between two successive fuel level readings measured during vehicle movement is not within permissible limits, it is considered that the vehicle goes in a ramp and hence the corresponding measurement will be ignored. To eliminate the effect of vibrations relevant in the fuel sensor output, the fuel sensor output is read every 5 msec and the readings pertaining to the last 2 seconds are averaged, before using intemally for various computations. The fuel pilferage monitoring is constantly carried out when the vehicle is not moving. At periodic intervals, the current fuel level is compared against the previous value (stored when vehicle is not moving). Any significant difference between these two values indicates the occurrence of pilferage. The pilferage thus detected is stored in non-volatile memory along with the date and time information. The RTC routine is invoked to get the date and time of pilferage. Whenever the system boots after power down, the pilferage routing is invoked and difference between the stored fuel level and the current fuel level is checked to determine the occurrence of fuel pilferage in the absence of power. Fuel level sensor failure is determined by monitoring the fiiel consumption when the engine is running. When there is no fuel consumption for a predefined distance, it is considered as a fuel level sensor failure. The outputs independent of this sensor will still be processed and they are not affected due to this sensor failure condition. In order to process the signal from the various sensors, hardware architecture needs to be chosen. The architecture used in the present invention is a micro controller with 8 kilobytes/ 16 kilobytes of on-chip memory, 512 bj^es of on-chip RAM and 720 bytes of flash programming ROM. Further this micro controller contains an 8-channel, 8 bit ADC with the required precision for monitoring the fuel sensor input. The architecture chosen is only preferred and the choice may vary depending on requirements. Accordingly the present invention provides a system for monitoring the liquid pilferage from a storage medium comprising a liquid level sensor for sensing the level of liquid in the medium; a processing means for processing said liquid level signal, said processing means having a signal conditioning means; a computing means for computing the information received from said sensor, said computing means having an analog to digital converter; said computing means is configured to relay signal to a display unit for displaying the date, time and amount of liquid pilfered. Also this invention provides a method for monitoring the liquid pilferage from a storage medium comprising the steps of acquiring the liquid level analog signal from the liquid storage medium at a given instant of time; feeding the said analog signal into an analog digital converter of a micro controller for receiving the output as a digital value corresponding to the liquid quantity; comparing the liquid quantity value with the previous value stored in a non-volatile memory, storing the measured value of the liquid pilfered, date, time in a non-volatile memory if pilferage has occurred. This novel system and method is described with the aid of the following accompanying drawings: Figure 1 shows the overall block diagram of the major modules Figure 2 shows the circuit interface of the fuel signal Figure 3 shows the various interfaces in the hardware architecture Figure 4 shows the various modules of the software architecture Figure 1 gives the overall picture of the major modules involved in the method for monitoring the features, especially monitoring the liquid pilferage. The input signals such as vehicle speed (1), the engine RPM (2) and fuel level (3) are acquired by sensors and the same is fed into a simplified trip computer (10). The simplified trip computer (STC)(10), comprises a signal conditioning module (6) where the information acquired from the input signal sensors are processed before being fed into the ADC (8a) and the other components of the micro controller (8). The fuel level sensor signal is an analog signal of range between 0-5.22V. This input signal is processed and scaled down to 0-4.3V before feeding to the ADC (8a) of the micro controller (8). The output of the ADC (8a) is used for computing essential parameters such as kilometers per liter, distance to empty and fuel pilferage. As shown in figure 2 the fuel sensor input signal is scaled down from 0-5.22V to 0-4.3V through a resistor divider (11) and then fed to channel 0 of the internal ADC. In addition a Diode (12) preferably a zener diode of 4.7V and a capacitor (13) is provided at this input pin to suppress any transients that arise in this pin. The analog supply voltage will be fed with 5V and reference voltage pin will be fed with 4.3V. The ADC conversion clock is set at IMHZ approximately. At this ADC clock frequency the time required for a single conversion is 17 )LIS. The ADC has a precision of 19mV. Hence the minimum change in the fuel level that can be detected is 0.9 liters. Since the ADC precision is much higher than the precision of the fuel level sensor (3 liters), no errors will be introduced by micro controller ADC. The system described above also comprises a push button key (or) a toggle switch (P) that enables switching between the various display parameters. In addition, the toggle switch is used for resetting the trip meter. The RTC keys are also connected to the I/O parts of the micro controller. The RTC keys Mode key (M), Up key (U) and Down key (D) are used for setting the RTC date and time values. Figure 3 elaborates on the different hardware interfaces. According to Figure 3 the display of the various trip parameters is given in a seven-digit seven- segment LED (7). More precisely a 3-digit seven-segment display and a 4-digit seven- segment display have been used for faster refreshing of the LED display. Segments corresponding to both the three digit and four digit LEDs are driven by one set of the eight I/O ports of the Controller. This multiplexing is achieved by employing a latch (14) to hold the data corresponding to four digit seven segment LED. A separate latch for the three digit LED display is not provided because the requirement is satisfied by the I/O ports of the micro controller itself. This data lines feed the base of the transistor array (15), which drives the LED displays. The transistor arrays (!5) derive the power directly from the 24V Battery power supply. This reduces the load on the Voltage Regulator, thereby eliminating the need for providing heat sink to 5 V regulator, which would have been required if it is used for driving LEDs. There is also provided an interface for the power supply. The system operates on a 24V battery supply from the vehicle (16). The 24V input from the vehicle battery is regulated to 5V. This 5V regulated supply is used for powering the hardware of the system. The 24V input is fed first to a series diode for reverse voltage protection and next to a register and a transient voltage suppressor combination to provide protection against voltage surges. The input supply is then stepped down through a series pass transistor. This series pass transistor shares a portion of the voltage drop and power dissipation. The supply is then fed to a voltage regulator, which converts the input to a 5V supply. Bulk electrolytic capacitors are provided at the input and output of the regulator. In addition, the battery voltage is fed to one of the ADC inputs of the micro controller. This feature can be utilized to monitor the battery health, if required. The system communicates with the serial EEPROM (17) and RTC (18) through the I/O port lines of the micro controller. Vehicle battery is regulated to 5V. This 5V regulated supply is used for powering the hardware of the system. The 24V input is fed first to a series diode for reverse voltage protection and next to a register and a transient voltage suppressor combination to provide protection against voltage surges. The input supply is then stepped down through a series pass transistor. This series pass transistor shares a portion of the voltage drop and power dissipation. The supply is then fed to a voltage regulator, which converts the input to a 5V supply. Bulk electrolytic capacitors are provided at the input and output of the regulator. In addition, the battery voltage is fed to one of the ADC inputs of the micro controller. This feature can be utilized to monitor the battery health, if required. The system communicates with the serial EEPROM (17) and RTC (!8) through the I/O port lines of the micro controller. According to Figure 4, the software architecture of the STC is categorized into 3 modules, namely, Scheduler Module (20), Driver Module (19) and Application Module (21). The Scheduler (20) is the core function that schedules the execution of all the STC tasks except the interrupt processing tasks. Depending upon priority, each task is executed in different pre-defined time slots of the Scheduler. The Scheduler invokes various modules pertaining to output generation, key input scanning, sensor failure detection, etc., in the appropriate time slots. The Scheduler tasks will be interrupted by the vehicle speed and engine RPM interrupts. The tasks running under Scheduler utilizes the data acquired by these interrupts for further computation. The different tasks running under Scheduler in tum calls the driver module as required. The different driver modules are I2C Driver Module (22), ADC Drive Module (23), Timer Module (24), Push Button key interpreter (25), RTC keys interpreter (26) and LED Driver Module (27). The I2C Driver Module (22) is used to access the on-board serial EEPROM (17) and the RTC (18). Selection between these two devices is done through known software. The analog to digital converter (ADC) driver module (23) is used to measure the fuel level. The design also has a provision to measure the battery voltage. The fuel level is measured from channel 0 and battery voltage can be measured from channel of ADC (8a). In KMPL and Distance to Empty (DTE) computation routines, if current fuel level is required, the ADC driver module is invoked. The Timer Module (24) is invoked for measuring the vehicle speed and engine RPM. The vehicle speed input signal is fed to channel 0 of timer I, which is programmed to generate an interrupt at every positive edge. The engine RPM input signal is fed to channel 1 of Timer 1, which is programmed to generate an interrupt for every positive edge. The push button key (25) is used to switch between the parameters displayed in 7 segment LED and to reset the Trip meter if the current display is trip meter. The RTC keys interpreter modules handles the functionality of setting RTC parameters. When the RTC parameters are changed, then the RTC routine is invoked to write the parameter into the respective registers to set date, month, year, hours, minutes and seconds. The above description should not be limited to the application as detailed above. The system and method of the present invention could be used for liquid monitoring in many other applications with only a slight variation of the hardware and the software that is obvious for a person skilled in the art. WE CLAIM: 1. A system for monitoring the liquid pilferage from a storage medium comprising a liquid level sensor for sensing the level of liquid in the medium; a processing means (10) for processing said liquid level signal, said processing means having a signal conditioning means (6); a computing means (8) for computing the information received from said sensor, said computing means (8) having an analog to digital converter (8a); a Real Time Clock (RTC) (18) is provided to monitor liquid pilferage or usage every second; a battery back up is additionally provided to provide power to the RTC (18) in the absence of the actual battery power supply (16); said computing means (8) comprising a storing media (17) for storing, in the event of liquid being pilfered, the pilfered quantity of liquid along with date and time; said computing means (8) also configured to relay signal to a display unit for displaying the date, time and amount of liquid pilfered. 2. The system as claimed in claim 1, wherein said signal conditioning means comprises a resistor divider provided to scale down said analog liquid level input signal from a range of 0-5.22V to a range of 0-4.3V. 3. The system as claimed in claim 1, wherein a diode and a capacitor are provided at the input of the said analog to digital converter to suppress transients that arise in the system. 4. The system as claimed in claim 3, wherein the said diode is a zener diode of 4,7V. 5. The system as claimed in claim 1, wherein the display unit is a three digit seven segment LED. 6. The system as claimed in claim 1 wherein the display is a four digit seven segment LED. 7. The system as claimed in any one of the claims 5 or 6 wherein the said displays are driven by one set of the plurality of I/O ports of the micro controller. 8. The system as claimed in any one of the claims 5 to 7 wherein a latch is employed to hold the data corresponding to four-digit seven segment LED. 9. The system as claimed in any one of the claims 5 to 8 wherein transistor arrays are provided to drive the LED displays. 10. The system as claimed in any one of the preceding claims, wherein said system operates on a battery power supply, said power supply being regulated for powering the hardware of the system. 11. The system as claimed in any one of the preceding claims wherein the said system for monitoring the liquid pilferage is incorporated in a vehicle. 12. The system as claimed in claim 10 wherein a toggle switch is provided to switch between the various parameters being displayed in the display unit such as distance to empty, real time mileage estimation and electronic odometer. 13. A method for monitoring the liquid pilferage from a storage medium comprising the steps of: acquiring the liquid level analog signal from the liquid storage medium at a given instant of time; feeding the said analog signal into an analog digital converter of a micro controller for receiving the output as a digital value corresponding to the liquid quantity; comparing the liquid quantity value with the previous value stored in a nonvolatile memory; storing the measured value of the liquid pilfered, date, time in a non-volatile memory if pilferage has occurred. 14. The method as claimed in claim 12 comprising the step of invoking a plurality of software modules for execution of the different tasks of the system in different pre defined time slots. 15. The method as claimed in claims 11 or 12, wherein the output generated by the plurality of software modules is communicated to output means for generating reports and analyzing the usage of the liquid being stored and used.

Documents:

1450-che-2004-abstract.pdf

1450-che-2004-claims.pdf

1450-che-2004-correspondnece-others.pdf

1450-che-2004-correspondnece-po.pdf

1450-che-2004-description(complete).pdf

1450-che-2004-drawings.pdf

1450-che-2004-form 1.pdf

1450-che-2004-form 26.pdf

1450-che-2004-form 3.pdf

1450-che-2004-form 9.pdf