JP2008121594A - Fuel system abnormality detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel system abnormality detection device making an exclusive fuel pressure sensor unnecessary in detection of clogging abnormality of a fuel pipe and the like other than fuel pump abnormality. <P>SOLUTION: EUC 10 judges that an air fuel ratio value is an abnormally large value, and judges that abnormality of the fuel system other than the fuel pump 30 such as an abnormal condition of at least one of the fuel pipe 34, a pressure regulator 33 and an injector 50 occurs when it is judged that rotation speed of a brushless motor 31 is normal, by using a detection value of a Hall element 312 necessary for controlling drive of the brushless motor 31 together with using a detection value of an oxygen concentration sensor 40 necessary for controlling fuel injection quantity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel system abnormality detection device that detects an abnormality such as clogging of a fuel passage.

2. Description of the Related Art Conventionally, there has been known an apparatus that detects an abnormal pump state in which a fuel pump is locked due to a foreign matter biting or the like (see Patent Document 1). Although not specifically described in Patent Document 1, in addition to the pump abnormality, the fuel pipe connected to the fuel pump and supplying fuel to the internal combustion engine may be clogged or connected to the fuel pipe. There may be an abnormality that causes clogging of an injector that injects fuel or a pressure regulator that adjusts the pressure of the fuel.
Conventionally, a fuel pressure sensor is provided to detect clogging abnormalities in these fuel pipes, etc. When the detected value of the fuel pressure sensor becomes abnormally high, clogging abnormalities in the fuel pipes etc. Is detected.

Japanese Patent Laid-Open No. 04-284155

However, in the above-described conventional structure, it is necessary to provide a dedicated fuel pressure sensor for detecting an abnormal clogging of a fuel pipe or the like, and such a fuel pressure sensor is expensive, resulting in a significant increase in cost.
SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel system abnormality detection device that eliminates the need for a dedicated fuel pressure sensor when detecting a clogging abnormality in a fuel pipe or the like in addition to a fuel pump abnormality.

According to the first aspect of the present invention, when it is determined that the value of the air-fuel ratio is an abnormally large value and the value of the rotational speed of the brushless motor is determined to be normal, the fuel pipe and the fuel flow control member It is determined that at least one of them is in an abnormal state.
Therefore, the fuel pipe and the fuel flow control member are used by utilizing the air-fuel ratio detection means necessary for controlling the fuel injection amount and the rotational position detection means necessary for controlling the drive of the brushless motor. It is possible to detect whether at least one is in an abnormal state. Therefore, a dedicated fuel pressure sensor can be dispensed with when detecting a clogging abnormality in the fuel pipe in addition to the fuel pump abnormality.

  In the invention according to claim 2, if the value of the rotational speed with respect to the applied voltage is within a predetermined range, it is determined that the fuel pump is normal. In the invention according to claim 3, the value of the rotational speed with respect to the applied voltage is within the predetermined range. If it is outside, it is determined that the fuel pump is in an abnormal state. Therefore, compared to the control in which the fuel pump is determined to be normal when the value of the rotational speed with respect to the applied voltage is larger than the predetermined lower limit value, and when the fuel pump is in an abnormal state when the value is smaller than the predetermined lower limit value. The case where the value of the rotational speed with respect to the applied voltage is excessive can also be determined as an abnormal state. Therefore, it is possible to reliably detect whether the fuel pump is normal or abnormal.

  In the invention according to claim 5, when the abnormality determination is performed by the fuel system abnormality determination unit or when the abnormality determination is performed by the pump abnormality determination unit, the motor control unit temporarily stops the rotation of the brushless motor. Then restart. According to this, since the pulsation of the fuel pressure is generated by restarting the pump after the pump is stopped once, it is possible to promote the removal of the clogged foreign matter at each part by the pulsation.

Hereinafter, a plurality of embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing a hardware configuration of the fuel system abnormality detection device according to the first embodiment, and the fuel pump 30 is driven and controlled by an ECU (electronic control device) 10 and a drive circuit 20. The fuel pump 30 includes a brushless motor 31 and a pump unit 32. The pump unit 32 has an impeller 321 that is rotationally driven by a brushless motor 31, and fuel is sucked and boosted as the impeller 321 rotates. The pressure of the fuel boosted by the pump unit 32 and discharged from the fuel pump 30 is adjusted by a pressure regulator 33 (fuel flow control member). The fuel whose pressure is adjusted by the pressure regulator 33 is supplied to an injector 50 (fuel flow control member) that circulates through the fuel pipe 34 and injects fuel into the intake air sucked into the combustion chamber of the engine (internal combustion engine). The

  Then, the ECU 10 calculates a target injection amount based on the engine speed, the throttle opening, and the like, and controls the operation of the injector 50 so that the fuel injection amount from the injector 50 becomes the target injection amount. Further, an oxygen concentration sensor 40 as an air-fuel ratio detection means is provided in the exhaust passage of the engine, and the detected value of the oxygen concentration is input to the ECU 10.

The ECU 10 detects the air-fuel ratio A / F of the air-fuel mixture sucked into the combustion chamber based on the detected oxygen concentration value from the oxygen concentration sensor 40. Then, the ECU 10 calculates a correction coefficient FAF for feedback correction of the target injection amount so that the detected air-fuel ratio A / F approaches the ideal air-fuel ratio, and executes so-called air-fuel ratio feedback correction control.
That is, if the detected value of the air-fuel ratio A / F is larger than the ideal air-fuel ratio, feedback correction is performed so as to increase the fuel injection amount by increasing the value of the correction coefficient FAF. On the other hand, if the detected air-fuel ratio A / F is smaller than the ideal air-fuel ratio, feedback correction is performed so as to decrease the fuel injection amount by decreasing the value of the correction coefficient FAF.

The fuel pump 30 is provided with a hall element 312 as a rotational position detecting means for detecting the rotational position of the brushless motor 31. The ECU 10 controls the operation of the drive circuit 20 based on the detection signal of the hall element 312. The drive circuit 20 has a plurality of switching circuits, and operates the switching circuit so that the drive voltage is sequentially applied to the windings 311 of the brushless motor 31.
The ECU 10 and the drive circuit 20 when controlling the operation of the drive circuit 20 in this way correspond to “motor control means” described in the claims.

Next, a method for detecting an abnormality in the fuel system by the ECU 10 will be described with reference to FIGS.
FIG. 2 is a flowchart showing control by the ECU 10. First, in step S10, an average value FAFAV per predetermined time of the correction coefficient FAF for feedback correction described above is calculated. In step S20, it is determined whether the correction coefficient average value FAFAV is equal to or greater than a predetermined value α. If FAFAV ≧ α (S20: Yes), there is an abnormality that the amount of fuel actually injected is less than the target injection amount due to the occurrence of an abnormality in the fuel system. 1 is added to the value CFAFAL of the fuel system abnormality detection counter.

Next, it progresses to step S40 and it is determined whether CFAFAL is more than predetermined value (beta). If CFAFAL ≧ β is satisfied after a predetermined time has elapsed since the occurrence of abnormality in the fuel system (S40: Yes), a fuel system abnormality determination routine S50 shown in FIG. 3 is executed. If the value of CFAFAL has not reached β (S40: No), the process returns to step S10.
In step S20, if FAFAV <α (S20: No), the value of CFAFAL is reset to zero, and the process returns to step S10.
Note that the ECU 10 when determining whether or not an abnormality has occurred in steps S20 and S40 that the fuel injection amount actually injected is smaller than the target injection amount is claimed. This corresponds to “fuel shortage abnormality determination means” described in the above item.

When the fuel system abnormality determination routine S50 is started, first, in step S510, the rotational speed NEFP of the fuel pump 30 is calculated based on the detected value of the Hall element 312. The ECU 10 when calculating the rotational speed NEFP in this way corresponds to “rotational speed calculation means” recited in the claims.
Thereafter, in step S520, the voltage value VBFP applied to the winding 311 of the brushless motor 31 is detected.

  Here, the relationship between the pump speed NEFP and the pump voltage value VBFP when the fuel pump 30 is operating normally is uniquely determined as shown by a solid line in FIG. Then, the range having a margin with respect to the solid line is the range indicated by the dotted lines L1 and L2 in FIG. 4, and if the detected rotational speed NEFP with respect to the detected voltage value VBFP is within this range, the fuel It is determined that the pump 30 is operating normally, and if it is out of the range, it is determined that a pump abnormality such as a foreign object biting into the impeller 321 has occurred.

  Specifically, the ECU 10 stores the map shown in FIG. 4 in advance, and in step S530, the rotational speed NEFP with respect to the voltage value VBFP is equal to or higher than the lower limit value γ shown in the dotted line L2 in FIG. It is determined whether or not it is equal to or less than the upper limit value δ shown. If the rotational speed NEFP is within a predetermined range (γ ≦ VBFP ≦ δ) (S530: Yes), it is considered that no abnormality has occurred in the fuel pump 30, and in step S540, the fuel system other than the fuel pump 30 is abnormal. Judge that there is. That is, it is determined that there is a fuel system abnormality in which an abnormality such as at least one of the fuel pipe 34, the injector 50, and the pressure regulator 33 is clogged with foreign matter. Thereafter, in step S550, a code ALCODE = 1 indicating that the fuel system other than the fuel pump 30 is abnormal is output.

  On the other hand, if the rotational speed NEFP is outside the predetermined range (S530: No), it is determined in step S560 that a pump abnormality has occurred. Examples of the pump abnormality include a case where foreign matter is caught in the impeller 321, a vapor lock is generated, a case where the impeller 321 is rotating in reverse. Thereafter, in step S570, a code ALCODE = 2 indicating that the fuel pump 30 is abnormal is output. When each code ALCODE = 1, 2 is output, an alarm or diagnostic lamp for notifying the vehicle occupant of the abnormality is activated. Depending on whether the code ALCODE is 1 or 2, notification is made in a different manner, such as changing the number of times the diagnostic lamp blinks.

  In addition, after performing control of step S10-S50 and step S510-S520, ECU10 when determining abnormality of the fuel pump 30 and abnormality other than a pump by step S530, "Pump" It corresponds to “abnormality determination means” and “fuel system abnormality determination means”.

  As described above, according to the first embodiment, the hall element 312 necessary for controlling the driving of the brushless motor 31 while using the oxygen concentration sensor 40 necessary for controlling the fuel injection amount from the injector 50 is used. It is possible to determine whether or not the fuel system other than the fuel pump 30 such as the fuel pipe 34 and the injector 50 is abnormal. Therefore, a dedicated fuel pressure sensor can be dispensed with when detecting an abnormality in the fuel system other than the fuel pump 30.

(Second Embodiment)
The control of the fuel system abnormality detection device according to the second embodiment of the present invention will be described below with reference to FIGS. In addition, the same code | symbol is attached | subjected to the process step part substantially the same as 1st Embodiment. The hardware configuration of the fuel system abnormality detection device according to the second embodiment is the same as that of the first embodiment, as shown in FIG. In addition, in the abnormality detection control of the fuel system abnormality detection device according to the second embodiment, the control content shown in FIG. 2 is the same control content as in the first embodiment, and thus the description thereof is omitted.

  In the second embodiment, when it is determined in step S530 that the rotational speed NEFP is outside the predetermined range and it is determined that a pump abnormality has occurred, the ECU 10 temporarily stops the rotation of the brushless motor 31. Pump restart control is executed such that the impeller 321 is restarted after being stopped.

  Specifically, as shown in FIG. 5, after the processing of steps S550 and S570, the process proceeds to step S580, and it is determined whether or not a code ALCODE = 2 indicating that the fuel pump 30 is abnormal is output. If ALCODE = 2 is not output (S580: No), the process returns to step S10. If ALCODE = 2 is output (S580: Yes), the pump restart routine S60 shown in FIG. 6 is executed. .

  When the pump restart routine S60 is started, first, in step S610, the voltage application to the winding 311 is stopped and the drive of the fuel pump 30 is stopped. Next, the pump stop counter CFPSTOP is started, and it is determined in step S620 whether or not CFPSTOP is equal to or less than a predetermined value μ. If the predetermined time has not yet passed since the voltage application to the winding 311 is stopped and CFPSTOP ≦ μ (S620: Yes), the value of the pump stop counter CFPSTOP is incremented by 1 in step S630.

  Thereafter, if the value of the pump stop counter CFPSTOP is not zero (S640: No), steps S620 and S630 are repeatedly performed, and when CFPSTOP> μ is satisfied after a predetermined time has elapsed after the voltage application to the winding 311 is stopped. (S620: No), it is assumed that the impeller 321 has completely stopped after a predetermined time, and the voltage application to the winding 311 is resumed in step S650, and the fuel pump 30 is restarted. In step S660, the value of the pump stop counter CFPSTOP is reset to zero. Therefore, an affirmative determination is made in subsequent step S640, and the process returns to step S510.

  As described above, according to the second embodiment, when it is determined in step S530 that a pump abnormality has occurred, the ECU 10 once stops the rotation of the brushless motor 31 and the impeller 321 stops. Pump restart control such as restart is executed. As a result, the fuel pressure pulsation is generated by restarting the fuel pump 30 after stopping the fuel pump 30. Therefore, it is possible to promote the removal of the clogged foreign matter by the impeller 321 and the like due to the pulsation.

(Other embodiments)
In each of the above embodiments, whether or not an abnormality has occurred in the fuel pump 30 is determined based on whether or not the detected value of the rotational speed NEFP with respect to the voltage value VBFP is within a predetermined range (γ ≦ VBFP ≦ δ), but the voltage value VBFP If the detected value of the rotational speed NEFP is smaller than the upper limit value indicated by the dotted line L1 in FIG. 4 (VBFP ≦ δ), no abnormality has occurred in the fuel pump 30, and if it exceeds the upper limit value, the fuel pump 30 It may be determined that an abnormality has occurred. Further, if the detected value of the rotational speed NEFP with respect to the voltage value VBFP is larger than the lower limit value shown by the dotted line L2 in FIG. 4 (γ ≦ VBFP), the abnormality of the fuel pump 30 has not occurred and the value is below the lower limit value. For example, it may be determined that an abnormality has occurred in the fuel pump 30.

  Also, the abnormality detection control shown in FIGS. 2 to 6 is preferably executed when the vehicle is in the following driving state. That is, for example, when the vehicle is traveling at a constant speed of 40 km / h for a predetermined time or more, when the accelerator opening is maintained at a constant opening for a predetermined time or during idle operation, Suitable when the driving state is stable

In addition, the fuel system abnormality detection device according to each of the above embodiments may be applied to a two-wheeled vehicle on which the engine is mounted, or may be applied to a four-wheeled vehicle.
Thus, the present invention is not limited to the above embodiments, and can be applied to various embodiments without departing from the scope of the invention.

The block diagram which shows the hardware constitutions of the fuel system abnormality detection apparatus which concerns on 1st Embodiment of this invention. The flowchart explaining the control content by ECU shown in FIG. The flowchart explaining the control content of the fuel system abnormality determination routine of FIG. The figure which shows the map used by the fuel system abnormality determination routine of FIG. The flowchart explaining the control content of the fuel system abnormality detection apparatus which concerns on 2nd Embodiment of this invention. The flowchart explaining the control content of the pump restart routine of FIG.

Explanation of symbols

  10: ECU (motor control means, fuel shortage abnormality determination means, rotation speed calculation means, pump abnormality determination means, fuel system abnormality determination means), 20: drive circuit (motor control means), 30: fuel pump, 31: brushless motor 32: Pump unit, 33: Pressure regulator (fuel flow control member), 34: Fuel piping, 40: Oxygen concentration sensor (air-fuel ratio detection means), 50: Injector (fuel flow control member), 312: Hall element ( Rotational position detection means).

Claims (7)

A fuel pump having a brushless motor, and a pump unit that is rotationally driven by the brushless motor to boost the fuel;
Rotational position detecting means for detecting the rotational position of the brushless motor;
Motor control means for controlling the drive of the brushless motor based on the detection value by the rotational position detection means;
A rotational speed calculation means for calculating the rotational speed of the brushless motor based on a detection value by the rotational position detection means;
A fuel pipe connected to the fuel pump for supplying fuel to the internal combustion engine;
A fuel flow control member connected to the fuel pipe and controlling the flow of the fuel;
Air-fuel ratio detection means for detecting the air-fuel ratio of the air-fuel mixture sucked into the internal combustion engine;
A fuel shortage abnormality determination means for determining whether or not the value of the air-fuel ratio detected by the air-fuel ratio detection means is an abnormally large value;
A pump abnormality determining means for determining whether or not the value of the rotational speed with respect to the voltage applied to the brushless motor is normal;
When the fuel shortage abnormality determining means determines that the air-fuel ratio value is an abnormally large value and the pump abnormality determining means determines that the rotational speed value is normal, the fuel pipe and the fuel pipe Fuel system abnormality determination means for determining that at least one of the fuel flow control members is in an abnormal state;
A fuel system abnormality detection device comprising:   2. The fuel system abnormality detection device according to claim 1, wherein the pump abnormality determination unit determines that the fuel pump is normal if the value of the rotation speed with respect to the applied voltage is within a predetermined range.   3. The fuel system abnormality detection device according to claim 1, wherein the pump abnormality determination unit determines that the fuel pump is in an abnormal state if the value of the rotation speed with respect to the applied voltage is outside a predetermined range.   The fuel flow control member includes at least one of an injector that injects fuel into intake air sucked into the internal combustion engine, and a pressure regulator that adjusts the pressure of fuel discharged from the fuel pump. The fuel system abnormality detection device according to any one of the above.   When an abnormality determination is made by the fuel system abnormality determination unit, or when an abnormality determination is made by the pump abnormality determination unit, the motor control unit temporarily stops rotation of the brushless motor and then restarts it. The fuel system abnormality detection device according to any one of claims 1 to 4.   The fuel system abnormality detection device according to any one of claims 1 to 5, wherein the air-fuel ratio detection means includes oxygen concentration detection means for detecting an oxygen concentration of exhaust gas discharged from the internal combustion engine.   The feedback correction of at least one of the fuel injection amount to the intake air sucked into the internal combustion engine and the throttle opening based on the value of the air-fuel ratio detected by the air-fuel ratio detection means. The fuel system abnormality detection device described.

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