Title of Invention

CONTROL APPARATUS FOR MOTOR-DRIVEN FLUID PUMP

Abstract A control apparatus for a motor-driven fluid pump, which includes a brushless motor for driving the fluid pump, includes rotational speed control means, actual speed computation means, supply voltage detection means, and rotational direction determination means. The rotational speed control means outputs a pulse width modulation signal to control a rotational speed of the brushless motor. The actual speed computation means computes an actual rotational speed of the fluid pump based on the pulse width modulation signal. The supply voltage detection means senses a supply voltage supplied to the fluid pump. The rotational direction determination means determines a rotational direction of the fluid pump based on the actual rotational speed of the fluid pump, which is computed by the actual speed computation means, and based on the supply voltage, which is sensed by the supply voltage detection means.
Full Text

CONTROL APPARATUS FOR MOTOR-DRIVEN FLUID PUMP
BACKGROUND OF THE INVENTION
1. Field of the Invention:
The present invention relates to a control apparatus for a motor-driven fluid pump.
2. Description of Related Art:
Conventionally, as this type of a control apparatus for a fluid pump, there has been known an apparatus for controlling a motor-driven fuel pump, which uses a motor as a drive source for intaking fuel from a vehicular fuel tank and for pumping the fuel (see, for example, JP-A-H4-284155). The apparatus disclosed in JP-A-H4-284155 detects a pump drive current, and when the drive current abnormally increases, the apparatus determines that the motor of the pump is locked, and thereby detecting an abnormal rotation of the fuel pump.
By the way, because a rotor magnet stops at different positions at different times, the motor may start rotating in a reverse direction, opposite from a normal rotational direction depending on the stopped position of the rotor. However, the apparatus disclosed in JP-A-H4-284155 can only detect the abnormal increase of the current at a time, where the motor of the pump is locked, but disadvantageously may not detect the reverse rotation of the pump, which associates with a small change of the current value.
SUMMARY OF THE INVENTION
The present invention is made in view of the above disadvantages. It is an objective to the present invention to provide a control apparatus for a motor-driven fluid pump operable to detect a rotational direction of the pump.
To achieve the objective of the present invention, there is provided a control

apparatus for a motor-driven fluid pump, which includes a brushless motor for driving the fluid pump, the control apparatus including rotational speed control means, actual speed computation means, supply voltage detection means, and rotational direction determination means. The rotational speed control means outputs a pulse width modulation signal to control a rotational speed of the brushless motor. The actual speed computation means computes an actual rotational speed of the fluid pump based on the pulse width modulation signal. The supply voltage detection means senses a supply voltage supplied to the fluid pump. The rotational direction determination means determines a rotational direction of the fluid pump based on the actual rotational speed of the fluid pump, which is computed by the actual speed computation means, and based on the supply voltage, which is sensed by the supply voltage detection means.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention, together with additional objectives, features and advantages thereof, will be best understood from the following description, the appended claims and the accompanying drawings in which:
FIG. 1 is a schematic structure diagram showing an engine control system according to an embodiment of the present invention;
FIG. 2 is a flow chart showing a pump reverse rotation determination / restart routine;
FIG. 3 is a chart showing a relation between a supply voltage to a motor and a pump rotational speed;
FIG. 4 is a circuit diagram showing a structure of a power supply system of a fuel pump module;
FIG. 5 is a circuit diagram showing a structure of a power supply system of a fuel pump module; and

FIGS. 6A and 6B are circuit diagrams each showing a structure of a power supply system of a fuel pump module.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS An embodiment of the present invention will be described referring to accompanying drawings. In the present embodiment, an engine control system is designed for a two-wheel vehicle gasoline engine, which serves as an internal combustion engine. The control system controls a fuel injection quantity and ignition timing by using an electronic control unit (hereinafter, referred as ECU) as the center. Firstly, a general schematic structure diagram of the engine control system will be described referring to FIG. 1.
In an engine 10 shown in FIG. 1, an air cleaner 12 is provided most upstream of an intake pipe 11, and a throttle valve 14 is provided downstream thereof. The air cleaner 12 is provided with an intake air sensor 13 for sensing an intake air temperature, and the throttle valve 14 is provided with a throttle opening sensor 15 for sensing a throttle opening. An intake pipe pressure sensor 16 is provided downstream of the throttle valve 14 for sensing an intake pipe pressure. Furthermore, a solenoid injector 17 is mounted at a vicinity of an intake port of the intake pipe 11.
The intake port and an exhaust port of the engine 10 are provided with an intake valve 21 and an exhaust valve 22, respectively, and an opening operation for opening the intake valve 21 introduces mixture of air and fuel into a combustion chamber 23. Then, an opening operation for opening the exhaust valve 22 discharges post-combustion exhaust gas to an exhaust pipe 24. The engine 10 has a cylinder head, where each cylinder is mounted with an ignition plug 25, and the ignition plug 25 is applied with a high voltage at desired ignition timing through an ignition device 26 made of ignition coil and the like. The application of the high

voltage generates spark discharge between opposing electrodes of each ignition plug 25 such that the mixture, which is introduced into the combustion chamber 23, is ignited and used for combustion.
The exhaust pipe 24 is provided with a catalytic converter 31, such as a three-way catalytic converter, for purifying CO, HC, NOx and the like in exhaust gas. Also, the exhaust pipe 24 is provided with an A/F sensor 32 upstream of the catalytic converter 31 for detecting the exhaust gas to sense an air fuel ratio of the mixture. Also, the engine 10 is provided with a coolant temperature sensor 33 for singing a coolant temperature and a crank angle sensor 34 for outputting a rectangular-shaped crank angle signal at every predetermined crank angle (e.g., 30° CA interval) while the engine 10 rotates.
Also, in a fuel system, an intank fuel pump module 42 is provided inside a fuel tank 41, and the fuel pump module 42 is connected with a delivery pipe 45 through a fuel pipe 43. The fuel pump module 42 includes a pump member 46, a motor 47, and a pressure regulator 44. Also, the fuel pump module 42 includes a fuel filter and a return pipe, which are not shown in FIG. 1. The motor 47 serves to rotate and drive the pump member 46, and the motor 47 and the pump member 46 rotate at the same rotational speed. Because a rotor magnet stops at different position at every time, the motor 47 may start rotating in a reverse direction, which is opposite a normal rotational direction, depending on the stop position. The pump member 46 is designed to pump fuel only during a normal rotation. Here, in the present embodiment, a brushless motor, which is a well-known sensor less type motor capable of controlling a rotational speed without rotational position sensor, serves as the motor 47.
The pressure regulator 44 adjusts pressure of fuel supplied from the fuel pump module 42. When pressure of fuel pumped by the pump member 46 of the fuel pump module 42 exceeds a preset pressure of the pressure regulator 44, it is

designed such that excessive fuel is returned to the fuel tank 41 through the return pipe. In other words, the fuel adjusted to have a predetermined pressure by the pressure regulator 44 is discharged from the fuel pump module 42 to the delivery pipe 45 through the fuel pipe 43, and the excessive fuel is returned to the fuel tank 41 from the return pipe.
An ECU 50 mainly includes a microcomputer having a CPU, a ROM, a RAM, and the like. The ECU 50 receives detection signals of the above various sensors and a detection signal of a supply voltage VP to the motor 47. The ECU 50 controls various control programs stored in the ROM and ignition timing of the ignition plug 25.
Here, the ECU 50 (rotational speed control means) outputs a pulse width modulation signal to the motor 47 to perform a rotational speed control of the motor 47. The motor 47 starts rotating based on a drive start signal from the ECU 50. The ECU 50 changes the pulse width modulation signal correspondingly to an induced voltage, which is generated at a stator coil due to the rotation of the rotor magnet of the motor 47, to increase the rotational speed. Then, the motor 47 converges to a predetermined rotational speed after a predetermined elapsed time.
A convergence value of the rotational speed (NEP) of the motor 47 (i.e., the rotational speed of the pump member 46, and hereinafter referred as "pump rotational speed") is determined based on a supply voltage (VP) to the motor 47 (hereinafter, refereed as "pump supply voltage") and has a relation shown in FIG. 3. FIG. 3 is a chart showing a relation between the pump supply voltage VP and the pump rotational speed NEP, and a solid line indicates a case, where the pump member 46 normally rotates, and a broken line indicates a case, where the pump member 46 reversely rotates. When the pump member 46 normally rotates, there are a rotational resistance of the pump member 46 itself and also a pump resistance of the fuel. In contrast, when the pumn member 46 reverselv rotates, the fuel cannot

be pumped and because the pump member 46 operates at idle, there is no pump resistance of fuel. Therefore, as shown in FIG. 3, the convergence value of the rotational speed becomes larger when the pump reversely rotates than normally rotates at the same pump supply voltage VR
Also, as above, the rotational speed of the motor 47 is controlled based on the pulse width modulation signal outputted from the ECU 50. In other words, a rotational position sensor and the like is not required to obtain an actual pump rotational speed NEP. However, the actual pump rotational speed NEP is detected based on a drive signal (pulse width modulation signal) of the motor 47 outputted by the ECU 50 itself.
FIG. 2 is a flow chart showing a reverse rotation determination/restart routine of the pump member 46. This routine is executed by the ECU 50 at every predetermined interval when the engine starts. It is determined whether or not the engine starts depending on whether or not an engine rotational speed is low (e.g., equal to or less than 2000 rpm).
In FIG. 2, at step S101, it is determined whether or not the pump member 46 operates. Determination at step S101 of whether or not the pump member 46 operates is made based on whether or not the ECU 50 outputs the drive signal to the motor 47.
When the determination result at step S101 is YES, control proceeds to step S102. At step S102 (supply voltage detection means), a pump supply voltage VP is detected, and the detection value is stored in the RAM. At step S103 (actual speed computation means), an actual pump rotational speed NEP is computed based on a wave form of the drive signal outputted from the ECU 50 to the motor 47, and then the computed value is stored in the RAM.
At step S104 (reference rotational speed computation means), a pump rotational speed (NEVP) during the normal rotation of the pump member 46 (normal

rotational speed in the present invention) is computed correspondingly to the pump supply voltage VP detected at step S102. Then, a determination reference rotational speed (NEVP + a) is computed by adding a correction value a (predetermined speed) to the above computed value. Here, the pump supply voltage VP and the corresponding pump rotational speed NEVP has a relation shown as a solid line in FIG. 3. This relation is prestored as a map in the ECU 50. Also, the correction value a, which compensates a manufacturing variation in manufacturing the pump member 46 and the like, is set to be proportional to the pump supply voltage VP, and is prestored as a map in the ECU 50. These maps are used to compute the determination reference rotational speed at step S104.
At step S105 (rotational direction determination means), it is determined whether or not the actual pump rotational speed NEP is larger than the determination reference rotational speed. At this step, it is determined whether or not the pump member 46 reversely rotates. In other words, when the pump member 46 normally rotates, the actual pump rotational speed NEP is approximately equal to a pump rotational speed NEVP that corresponds to the pump supply voltage VP. In contrast, when the pump member 46 reversely rotates, the actual pump rotational speed NEP is larger than the pump rotational speed NEVP that corresponds to the pump supply voltage VP during the normal rotational state of the pump member 46. At step S105, a rotational direction of the pump member 46 is determined by using the above characteristic. When the determination result at step S105 is YES, the actual pump rotational speed NEP is larger than the determination reference rotational speed, and thereby determining that the pump member 46 reversely rotates.
When the determination result at step S105 indicates NO, in other words, when it is determined that the pump member 46 normally rotates, the present process directly ends. In contrast, when the determination result at step S105 is

YES, in other words, when it is determined that the pump member 46 reversely rotates, control proceeds to step S106, at which a pump reverse rotation flag FFPREVS is set as 1. At step S107, an output of the drive signal to the motor 47 is stopped such that the drive of the pump member 46 is stopped. Then, at step S108, in order to allow a user to know an abnormal mode that is the reverse rotation of the pump member 46, a diagnosis lamp is lit. Then, at step S109, a pump drive stop duration timer TREST is set as 0, and the present process ends.
When the determination result at step S101 is NO, in other words, when the pump member 46 stops, control process to step S110. Astop state, where the pump member 46 stops, is, for example, a state, where the drive of the pump member 46 is stopped because the reverse rotation of the pump member 46 is detected. At step
5110, a pump drive stop duration timer TREST is incremented (+1). Then, at step
5111, the pump drive stop duration timer TREST is compared with a predetermined reference value p. At step S111, it is determined whether or not a predetermined time has elapsed since the output of the drive signal from the ECU 50 to the motor 47 is stopped, and thereby the rotation of the pump member 46 is completely stopped. Typically, the reference value p is set as a value, which approximately corresponds the complete stop of the rotation of the pump member 46 (e.g., a value approximately corresponding to a few hundreds ms).
When the determination result at step S111 is YES, the pump member 46 completely stops, and thereby determining that the pump member 46 is restartable. Therefore, the output of the drive signal to the motor 47 is restarted at step S112 to restart the pump member 46. Then, at step S113 the pump reverse rotation flag FFPREVS is set as 0, and the diagnosis lamp is turned off at step S114. After this, the present process ends. In contrast, when the determination result at step S111 is NO, it is determined that the rotation of the pump member 46 has not been completely stopped. Thus, the present process ends without restarting the rotation

of the pump member 46.
According to the above detailed embodiment, advantages below can be achieved.
In the present embodiment, the determination reference rotational speed computed based on the pump rotational speed NEVP, which corresponds to the pump supply voltage VP, is compared with the actual pump rotational speed NEP of the pump member 46 to determine the rotational direction of the pump member 46. The presence of the pump resistance of the fuel depends on whether the pump member 46 normally rotates or reversely rotates. Therefore, the rotational speed varies even at the same pump supply voltage VP due to the pump resistance of the fuel. By using this characteristic, the rotational direction of the pump member 46 can be accurately determined.
Specifically, in the present embodiment, the determination reference rotational speed is set as a value larger by the correction value a than the pump rotational speed NEVP, which corresponds to the pump supply voltage VP during the normal rotation of the pump member 46. Therefore, even when there is manufacturing variation in manufacturing the pump member 46, the rotational direction of the pump member 46 can be determined accurately.
Because the brushless motor is employed in the present embodiment, the actual pump rotational speed NEP can be computed based on the pulse width modulation signal, which is used for controlling the pump rotational speed. As a result, a rotational position sensor (e.g., a rotational speed sensor) is not required, and therefore, the structure of the motor 47 and the structure of the pump module 42 can be simplified.
In the present embodiment, when it is determined that the pump member 46 reversely rotates, the pump member 46 is temporally stopped. Thereafter, the pump member 46 is restarted. Conventionally, the motor 47, which drives and rotates the

pump member 46, may reversely rotate depending on a position of the rotor magnet when stopped. However, in consideration of this, in the present embodiment, when it is determined that the pump member 46 reversely rotates, the pump member 46 is temporally stopped, and then is restarted. As a result, a state, where the pump member 46 reversely rotates, can be cancelled. That is, the motor 47, which reversely rotates, is temporally stopped, and then is rotated again such that the rotational direction can be put back to the normal direction. Also, by canceling the reverse rotational state, the fuel can be supplied to the engine 10, and therefore a performance for starting the engine 10 can be improved.
In the present embodiment, when it is determined that the pump member 46 reversely rotates, the diagnosis lamp is lit. As a result, the user can be informed of the abnormal mode that is the reverse rotation of the pump member 46.
Here, a structure of the power supply system for the fuel pump module 42 (the motor 47) will be described referring to FIG. 4.
In FIG. 4, a battery 61 is connected with the fuel pump module 42 and the ECU 50 through an ignition switch (hereinafter, referred as an IG switch) 62, and when the IG switch 62 is turned on (closed) based on a start operation of a driver, power is supplied from the battery 61 to the fuel pump module 42 and the ECU 50.
The ECU 50 has a microcomputer (micro-computer) 51, and the microcomputer 51 is connected with a VP detection circuit 52 that detects the pump supply voltage VP, and with a transistor 53 that constitutes a pump drive circuit. The fuel pump module 42 has one terminal (plus side terminal) connected with the IG switch 62, and has the other terminal (minus side terminal) connected with a collector of the transistor 53. Also, the transistor 53 has a base connected with the microcomputer 51, and has an emitter that is grounded. In the structure shown in FIG. 4, the VP detection circuit 52 detects a voltage on a path of an electric current of the fuel pump module 42 as the pump supply voltage VP, the voltage being between

the IG switch 62 and the fuel pump module 42 (the plus side terminal voltage of the fuel pump module 42). Here, the ECU 50 has, as a power supply system configuration, a power circuit, which generates a power voltage (e.g., Vcc=5V) for operating the microcomputer based on a battery voltage supplied through the IG switch 62. Illustration of the power circuit is omitted.
Here, the microcomputer 51 outputs a pump drive signal to the transistor 53, and power supply to the fuel pump module 42 is turned on and off in accordance with the pump drive signal. In other words, when the pump drive signal is off signal (L level signal), the transistor 53 is turned off, and the power supply to the fuel pump module 42 is stopped. Also, when the pump drive signal is on signal (H level signal), the transistor 53 is turned on, and therefore the power supply to the fuel pump module 42 is operated.
The microcomputer 51 successively receives the pump supply voltage VP detected by the VP detection circuit 52, and the microcomputer 51 determines the rotational direction of the fuel pump module 42 based on the pump supply voltage VP.
Also, FIG. 5 shows a structure using a relay circuit as a structure for turning on and off the power supply to the fuel pump module 42. Here, in FIG. 5, similar structures similar to the above structure in FIG. 4 are indicated by the same numerals and explanation thereof will be omitted.
In FIG. 5, on the path of the electric current of the fuel pump module 42, a normally open relay circuit 63 is provided between the IG switch 62 and the fuel pump module 42. The relay circuit 63 includes a switch 63a and a coil 63b, and the coil 63b has one end connected with the pump path of the electric current (between the IG switch 62 and the switch 63a), and has the other end connected with the collector of the transistor 53. Also, the VP detection circuit 52 is connected between the coil 63b and the collector of the transistor 53. In a structure in FIG. 5, the VP

detection circuit 52 detects a terminal voltage of the relay circuit 63 as the pump supply voltage VP.
When the pump drive signal outputted from the microcomputer 51 turns on the transistor 53, the coil 63b is energized. Then, the energization thereof turns on the switch 63a, and power supply to the fuel pump module 42 is operated. Also, similar to the above, the microcomputer 51 successively receives the pump supply voltage VP detected by the VP detection circuit 52, and the microcomputer 51 determines the rotational direction of the fuel pump module 42 based on the pump supply voltage VP.
In the structure in FIG. 5, the relay circuit 63 is provided between the IG switch 62 and the fuel pump module 42, however, the relay circuit 63 may alternatively be provided between the fuel pump module 42 and a ground.
As an alternative configuration of the power supply system for the fuel pump module 42, structures shown in FIGS. 6A, 6B may be employed. Here, in FIGS. 6A, 6B, similar structures similar to the above structures shown in FIG. 4 and FIG. 5 are indicated by the same numerals, and explanation thereof will be omitted.
In FIG. 6A, an injector 17 is connected with a portion between the relay circuit 63 and the fuel pump module 42 on the path of the electric current of the fuel pump module 42. The injector 17 has a plus side terminal connected with the relay circuit 63, and has a minus side terminal connected with a collector of a transistor 54, which constitutes an injector drive circuit. Also, the VP detection circuit 52 is connected between the minus side terminal of the injector 17 and the collector of the transistor 54. In the structure shown in FIG. 6A, the VP detection circuit 52 detects a minus side terminal voltage of the injector 17 as the pump supply voltage VP.
When the transistor 54 is turned on by the injector drive signal outputted from the microcomputer 51, the injector 17 is energized. Then, a valve of the injector 17 is opened along with the energization thereof, and therefore the fuel

injection to the engine is operated. Also, similar to the above, the microcomputer 51 successively receives the pump supply voltage VP detected by the VP detection circuit 52, and the microcomputer 51 determines the rotational direction of the fuel pump module 42 based on the pump supply voltage VP.
Also, in FIG. 6B, a VM detection circuit 55 for detecting a monitor voltage VM is connected with a portion between the relay circuit 63 and the plus side terminal of the injector 17. Here, the monitor voltage VM is a parameter for performing a voltage correction of a drive signal time in a fuel injection control by the injector 17, and in the fuel injection control, the drive signal time is corrected in consideration of a relation between the monitor voltage VM and an operation delay time (invalid injection time). In the structure shown in FIG. 6B, the monitor voltage VM (in other words, the plus side terminal voltage of the injector 17) detected by the VM detection circuit 55 corresponds to the pump supply voltage VP.
The microcomputer 51 successively receives the monitor voltage VM detected by the VM detection circuit 55, and the microcomputer 51 determines the rotational direction of the fuel pump module 42 based on the monitor voltage VM.
Here, the present invention is not limited to the above embodiments, but may be applied in the following manner.
In the above embodiments, when it is determined that the pump member 46 reversely rotates, the diagnosis lamp is lit in order to inform the user of the abnormal mode of the reverse rotation of the pump member 46. However, the user may be informed of the reverse rotation of the pump member 46 by sound and the like instead of by the lamp.
In the above embodiments, when it is determined that the pump member 46 reversely rotates, the pump member 46 is temporally stopped, and thereafter is restarted. Also, in a case, where the pump member 46 still reversely rotates even after the restart, the stop and restart are repeated until the pump member 46

normally rotates. However, even when the pump member 46 does not normally rotate after the stop and restart are repeated more than a predetermined number of times, the pump member 46 or the motor 47 may malfunction. Therefore, the execution number of the stop and restart may be counted, and when the stop and restart are successively executed more than or equal to the predetermined number of times (e.g., five times) until the pump member 46 starts normally rotating, a possible malfunction of the fuel pump module 42, including the pump member 46 and the motor 47, may be alternatively informed of the user. Also, in this case, diagnosis code may be outputted. Thus, the possibility of malfunction can be accurately determined.
When the engine starts, in other words, when the fuel pump module 42 is started, because the pump rotational speed NEP delays in increasing relative to the increase of the pump supply voltage VP, the relation between the pump supply voltage VP and the pump rotational speed NEP may be broken, and therefore the relation shown in FIG. 3 may not be established. Thus, during a post-start predetermined period, in which a predetermined period elapses since a time of starting the pump, (possibly a predetermined period after the start of the engine), the determination of the pump rotational direction is prohibited from being executed, and at timing, where the post-start predetermined period has elapsed, the determination of the pump rotational direction may be executed. Due to this, disadvantage, such as erroneous determination of the pump rotational direction immediately after the start of the pump, can be limited.
Also, an alternative structure may be applied, in which the elapsed time since a time of the start of the pump may be replaced with the pump rotational speed NEP, which is used as a parameter for permission or inhibition of determination of the pump rotational direction. In other words, after the start of the pump, the determination of the pump rotational direction may be prohibited from being

executed until the pump rotational speed NEP increases to reach a predetermined rotational speed. Then, at a time, where the pump rotational speed NEP reaches the predetermined rotational speed, the determination of the pump rotational direction may be executed. Here, the predetermined rotational speed may be a pump rotational speed, which is assumed to satisfy the relation shown in FIG. 3. Alternatively, the determination of the pump rotational direction may be executed at timing, when one of the followings is satisfied after the start of the pump: the post-start predetermined period has elapsed and the pump rotational speed NEP has reached the predetermined rotational speed.
In the above embodiments, examples, in which the present control system is applied to the engine for a two-wheel vehicle, are described. However, the application of the present control system is not limited to the two-wheel vehicle, but is applicable to other vehicles. Specifically, the present control system may be applied to a small vehicle, such as a farm vehicle, in addition to the two-wheel vehicle. Due to this, even in a vehicle with a simple system, the rotation of the pump member 46 of the fuel pump module 42 can be reliably controlled with a minimum addition. Also, in the above embodiments, the rotational direction of the pump member 46, which pumps the fuel, is determined. However, the present invention is not limited to a pump for supplying the fuel, but is applicable to a general fluid pump for pumping other fluid.
In the above embodiments, a structure is described as an example, where the power (power supply) is supplied to the fuel pump module from the vehicle battery. However, as a modification, another structure may be employed, where a power generator (e.g., alternating current generator) for generating power using an engine as a drive source supplies power to the fuel pump module. In this structure, similar to the above, the pump rotational direction can be determined based on a corresponding pump rotational speed and a corresponding pump supply voltage.

Additional advantages and modifications will readily occur to those skilled in the art. The invention in its broader terms is therefore not limited to the specific details, representative apparatus, and illustrative examples shown and described.


















































What is claimed is:
1. A control apparatus for a motor-driven fluid pump, which includes a
brushless motor for driving the fluid pump, the control apparatus comprising:
rotational speed control means for outputting a pulse width modulation signal to control a rotational speed of the brushless motor;
actual speed computation means for computing an actual rotational speed of the fluid pump based on the pulse width modulation signal;
supply voltage detection means for sensing a supply voltage supplied to the fluid pump; and
rotational direction determination means for determining a rotational direction of the fluid pump based on the actual rotational speed of the fluid pump, which is computed by the actual speed computation means, and based on the supply voltage, which is sensed by the supply voltage detection means.
2. The control apparatus according to claim 1, further comprising:
reference rotational speed computation means for computing a reference
rotational speed based on the supply voltage sensed by the supply voltage detection means, wherein:
the rotational direction determination means compares the reference rotational speed, which is computed by the reference rotational speed computation means, with the actual rotational speed of the fluid pump, which is computed by the actual speed computation means; and
the rotational direction determination means determines that the fluid pump reversely rotates when the actual rotational speed of the fluid pump is larger than the reference rotational speed.

3. The control apparatus according to claim 2, wherein:
the reference rotational speed computation means computes a normal rotational speed, which corresponds to the supply voltage, by using a predetermined map indicative of a relation between the supply voltage and the normal rotational speed during a normal rotational state, where the fluid pump normally rotates; and
the reference rotational speed computation means computes the reference rotational speed as a value, which is greater by a predetermined speed than the normal rotational speed computed by using the predetermined map.
4. The control apparatus according to claim 1, wherein:
the fluid pump is stopped, and is subsequently restarted when the rotational direction determination means determines that the fluid pump reversely rotates.
5. The control apparatus according to claim 4, further comprising:
malfunction determination means for determining a malfunction of the fluid
pump when the fluid pump is successively stopped and restarted by equal to or more than a predetermined number of times.
6. The control apparatus according to any one of claims 1 through 5, wherein:
the fluid pump is a fuel supply pump for an internal combustion engine.


Documents:

1124-che-2007 amended claims 01-06-2011.pdf

1124-che-2007 form-3 01-06-2011.pdf

1124-CHE-2007 AMENDED PAGES OF SPECIFICATION 14-02-2011.pdf

1124-CHE-2007 AMENDED CLAIMS 14-02-2011.pdf

1124-CHE-2007 CORRESPONDENCE OTHERS 01-06-2011.pdf

1124-CHE-2007 ENGLSIH TRANSLATION.pdf

1124-CHE-2007 EXAMINATION REPORT REPLY RECEIVED 14-02-2011.pdf

1124-che-2007 form-3 14-02-2011.pdf

1124-CHE-2007 OTHER PATENT DOCUMENT 14-02-2011.pdf

1124-CHE-2007 POWER OF ATTORNEY 14-02-2011.pdf

1124-che-2007-abstract.pdf

1124-che-2007-claims.pdf

1124-che-2007-correspondnece-others.pdf

1124-che-2007-description(complete).pdf

1124-che-2007-drawings.pdf

1124-che-2007-form 1.pdf

1124-che-2007-form 3.pdf

1124-che-2007-form 5.pdf

1124-che-2007-form18.pdf


Patent Number 248443
Indian Patent Application Number 1124/CHE/2007
PG Journal Number 29/2011
Publication Date 22-Jul-2011
Grant Date 15-Jul-2011
Date of Filing 30-May-2007
Name of Patentee DENSO CORPORATION
Applicant Address 1-1, SHOWA-CHO, KARIYA-CITY, AICHI-PREF. 448-8661, JAPAN
Inventors:
# Inventor's Name Inventor's Address
1 KURODA, TAKAHIKO C/O DENSO CORPORATION, 1 SHOWA-CHO, KARIYA-CITY, AICHI 448-8661, JAPAN
2 NAGATA, KIYOSHI 1-1, SHOWA-CHO, KARIYA-CITY, AICHI-PREF. 448-8661, JAPAN
3 OOTAKE, MASAYA 1-1, SHOWA-CHO, KARIYA-CITY, AICHI-PREF. 448-8661, JAPAN
PCT International Classification Number H02P1/46
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2006-150840 2006-05-31 Japan
2 2007-100139 2007-04-06 Japan