JP2011052568A - Failure determining device of high pressure fuel pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a failure determining device of high pressure fuel pumps, properly performing failure determination on each of the first and second high pressure fuel pumps provided parallel to each other while specifying which of excessive discharge failure and non-discharge failure is the failure pattern. <P>SOLUTION: The failure determining device 1 of the high pressure fuel pumps determines the failure of the first high pressure fuel pump 30 while specifying the failure pattern in a state that operation of the second high pressure fuel pump 40 is stopped when the absolute value ¾DPF¾ of a difference between fuel pressure PF, which is feedback-controlled so that it reaches a target fuel pressure PFCMD, and the target fuel pressure PFCMD is larger than a threshold value PREF (steps 6, 7, 21-25). When determining that no failure occurs in the first high pressure fuel pump 30, the failure determination device performs the failure determination of the second high pressure fuel pump 40 in the same manner (steps 27-34). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a failure determination device for a high-pressure fuel pump that determines failure of a high-pressure fuel pump provided in a fuel supply system of an internal combustion engine.

  As a conventional high-pressure fuel pump failure determination device, for example, one disclosed in Patent Document 1 is known. This internal combustion engine is a V-type 8-cylinder, and two high-pressure fuel pumps are provided in parallel with each other in the fuel supply system. The high-pressure fuel discharged from each high-pressure fuel pump is supplied to an injector provided for each cylinder, and is directly injected into each cylinder from the injector and used for combustion.

  Further, in this failure determination device, after one high-pressure fuel pump is stopped, failure determination of the two high-pressure fuel pumps is sequentially performed in a state where the other high-pressure fuel pump is controlled by a drive signal having a predetermined duty ratio. In this failure determination, when the fuel pressure (fuel pressure) on the discharge side of the high-pressure fuel pump does not increase, it is determined that a non-discharge failure in which fuel cannot be discharged has occurred in the high-pressure fuel pump to which the drive signal is output.

JP 2006-37920 A

  However, since this conventional failure determination device only determines a non-discharge failure of the high-pressure fuel pump when the fuel pressure does not increase, even if the fuel pressure increases beyond an appropriate range, the failure of the high-pressure fuel pump Cannot be determined. Therefore, for example, even when an overdischarge failure occurs while fuel is discharged to the high-pressure fuel pump, this cannot be determined as a failure of the high-pressure fuel pump.

  The present invention has been made in order to solve the above-described problems, and the first and second high-pressure fuel pumps provided in parallel with each other have a failure due to any failure pattern of overdischarge failure or non-discharge failure. An object of the present invention is to provide a failure determination device for a high-pressure fuel pump that can appropriately determine a failure of a high-pressure fuel pump while specifying the failure pattern even when the failure occurs.

  In order to achieve the above object, the invention according to claim 1 of the present application is directed to a fuel supply system that supplies fuel to the fuel injection valve 4 that injects fuel into the cylinder 7 (hereinafter, the same applies in this embodiment). A failure determination device 1 for a high-pressure fuel pump that determines failure of a first high-pressure fuel pump 30 and a second high-pressure fuel pump 40 provided in parallel to each other in a supply device 10). A low pressure fuel pump 50 for increasing the feed pressure PFEED, a low pressure fuel supply passage (low pressure delivery pipe 14) for supplying low pressure fuel discharged from the low pressure fuel pump 50 to the first and second high pressure fuel pumps 30 and 40; A high-pressure fuel supply passage (high-pressure delivery pipe 15) for supplying high-pressure fuel discharged from the first and second high-pressure fuel pumps 30 and 40 to the fuel injection valve 4, and a high-pressure fuel Fuel pressure detecting means (fuel pressure sensor 21) for detecting the fuel pressure in the supply passage as fuel pressure PF, and bypass passages for bypassing the first and second high-pressure fuel pumps 30 and 40 (first bypass pipe 16a, second bypass pipe 16b) ) And a relief valve 17 that is provided in the bypass passage and opens when the fuel pressure PF becomes higher than a predetermined valve opening pressure (relief pressure PREL), and allows the fuel to escape from the high-pressure fuel supply passage to the low-pressure fuel supply passage; The high-pressure fuel pump control means (ECU 2, FIG. 11) that feedback-controls the first and second high-pressure fuel pumps 30 and 40, the fuel pressure PF and the target fuel pressure so that the detected fuel pressure PF becomes a predetermined target fuel pressure PFCMD. When the deviation from PFCMD (absolute value of fuel pressure deviation DPF | DPF |) is larger than a predetermined threshold value DREF, the second high-pressure fuel pump 40 is turned on. When the fuel pressure PF reaches the valve opening pressure of the relief valve 17 while the second high-pressure fuel pump 40 is stopped, an over-discharge failure occurs while the fuel is discharged to the first high-pressure fuel pump 30. When the fuel pressure PF decreases to the feed pressure PFEED of the low-pressure fuel pump 50, a failure determination means (ECU2) determines that a non-discharge failure in which fuel cannot be discharged has occurred in the first high-pressure fuel pump 30. , Steps 6 and 7 in FIG. 6 and Steps 21 to 26 in FIG. 7.

  In the fuel supply system of the internal combustion engine, the fuel in the fuel tank is boosted to the feed pressure by the low-pressure fuel pump and then supplied to the first and second high-pressure fuel pumps in parallel with each other via the low-pressure fuel supply passage. At the same time, the high-pressure fuel discharged from the first and second high-pressure fuel pumps is supplied to the fuel injection valve via the high-pressure fuel supply passage. The supplied fuel is injected from the fuel injection valve into the cylinder and used for combustion. The fuel supply system is provided with a bypass passage with a relief valve that bypasses the first and second high-pressure fuel pumps, and the fuel pressure in the high-pressure fuel supply passage becomes greater than a predetermined valve opening pressure. Further, when the relief valve is opened, fuel is released from the high pressure fuel supply passage to the low pressure fuel supply passage. The first and second high-pressure fuel pumps are feedback-controlled so that the detected fuel pressure becomes a predetermined target fuel pressure.

  According to the failure determination device of the present invention, the failure determination of the first high-pressure fuel pump is executed when the deviation between the fuel pressure and the target fuel pressure is larger than a predetermined threshold value. If both the first and second high-pressure fuel pumps are normal, the fuel pressure in the high-pressure fuel supply passage follows the target fuel pressure satisfactorily by the feedback control described above, so that the deviation between the two becomes small. Therefore, when the deviation between the fuel pressure and the target fuel pressure becomes larger than the threshold value during the feedback control, it is assumed that one of the two high-pressure fuel pumps may have failed, and the first timing is determined at an appropriate timing. It is possible to determine the failure of the high-pressure fuel pump.

  Further, since the operation of the second high-pressure fuel pump is stopped prior to the failure determination, the failure determination of the first high-pressure fuel pump can be appropriately performed without being affected by the operation. Further, when the fuel pressure reaches the valve opening pressure, it is determined that an overdischarge failure occurs while the fuel is discharged to the first high-pressure fuel pump, and when the fuel pressure decreases to a predetermined supply pressure of the low-pressure fuel pump. Since it is determined that a non-discharge failure that cannot discharge fuel has occurred in the first high-pressure fuel pump, the failure pattern is specified when either an over-discharge failure or a non-discharge failure occurs. However, the failure of the first high-pressure fuel pump can be determined appropriately.

  According to a second aspect of the present invention, in the high pressure fuel pump failure determination device 1 according to the first aspect, when the failure determination means determines that no failure has occurred in the first high pressure fuel pump 30, The operation of the high-pressure fuel pump 30 is stopped, and a failure of the second high-pressure fuel pump is determined (steps 27 to 34 in FIG. 7).

  According to this configuration, when it is determined that no failure has occurred in the first high-pressure fuel pump, after stopping the operation of the first high-pressure fuel pump, the same method as the above-described failure determination of the first high-pressure fuel pump, A failure of the second high pressure fuel pump is determined. Therefore, the failure determination of the second high-pressure fuel pump can be performed appropriately while specifying the failure pattern without being affected by the operation of the first high-pressure fuel pump, and either of the first and second high-pressure fuel pumps has failed. It can be clearly identified whether it has occurred.

  According to a third aspect of the present invention, in the failure determination device 1 of the high pressure fuel pump according to the first or second aspect, the failure determination means is configured such that the deviation between the fuel pressure PF and the target fuel pressure PFCMD is equal to or less than the threshold value PREF and feedback. When the feedback value (fuel pressure feedback value KHPUMP) set in the control is not within a predetermined range (KHPUMPL <KHPUMP <KHPUMPH), failure determination is executed (steps 8 to 11, FIG. 8, FIG. 9 in FIG. 6). It is characterized by.

  According to this configuration, the failure determination is performed when the deviation between the fuel pressure and the target fuel pressure is equal to or less than the threshold value and the feedback value set in the feedback control is not within the predetermined range. Even when the difference between the fuel pressure and the target fuel pressure does not appear clearly, it is possible to determine the necessity of failure determination based on the magnitude of the feedback value, and to execute the failure of the high-pressure fuel pump at a more appropriate timing.

1 is a diagram schematically showing a fuel supply device for an internal combustion engine to which a failure determination device for a high-pressure fuel pump according to an embodiment of the present invention is applied. It is a block diagram which shows schematic structure of a failure determination apparatus. It is sectional drawing which shows a high pressure fuel pump in the completion | finish timing of a suction process. It is sectional drawing which shows the high pressure fuel pump in a spill process. It is sectional drawing which shows the high pressure fuel pump in the completion | finish timing of a discharge stroke. It is a flowchart which shows the failure determination process of a high pressure fuel pump. It is a flowchart which shows the 2nd failure determination process of a high pressure fuel pump. It is a flowchart which shows the 3rd failure determination process of a high pressure fuel pump. It is a flowchart which shows the 4th failure determination process of a high pressure fuel pump. It is a table which shows a failure pattern of a high-pressure fuel pump. It is a flowchart which shows the control processing of a fuel pressure. It is a figure which shows roughly the other fuel supply apparatus of the internal combustion engine to which the failure determination apparatus of the high pressure fuel pump by embodiment is applied.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 2, the failure determination device 1 for a high-pressure fuel pump according to an embodiment of the present invention includes an ECU 2, which performs various control processes of the internal combustion engine 3 such as a fuel injection amount control process. Do.

  As shown in FIG. 1, the internal combustion engine 3 (hereinafter referred to as “engine 3”) is a V-type 8-cylinder DOHC type gasoline engine mounted on a vehicle (not shown). A cylinder 7 (# 1 to 4) and four cylinders 7 (# 5 to 8) in the left bank are provided.

  The engine 3 includes a fuel injection valve (hereinafter referred to as an “injector”) 4 and a spark plug 5 provided for each cylinder, a fuel supply device 10 that supplies fuel to each injector 4, and the like. The engine 3 is an in-cylinder injection type, and fuel is directly injected into the corresponding cylinder 7 from each injector 4, and the air-fuel mixture generated in the cylinder 7 is ignited by the spark plug 5. Is done.

  The opening and closing of the injector 4 is controlled by a control signal from the ECU 2, whereby the fuel injection timing is controlled by the valve opening timing, and the fuel injection amount QINJ is controlled by the valve opening time.

  The fuel supply device 10 includes a fuel tank 11 for storing fuel, a low pressure fuel pump 50 provided in the fuel tank 11, first and second high pressure fuel pumps 30 and 40, a low pressure delivery pipe 14, A high-pressure delivery pipe 15 is provided.

  The low-pressure fuel pump 50 is an electric type controlled by the ECU 2 and is always operated while the engine 3 is operating. The low-pressure fuel pump 50 sucks the fuel in the fuel tank 11 through the fuel suction passage 12, boosts the fuel to a predetermined low-pressure feed pressure PFEED (for example, 392 kPa), and then discharges it to the low-pressure delivery pipe 14. The fuel is returned into the fuel tank 11 through the fuel return path 13.

  The downstream side of the low-pressure delivery pipe 14 is branched into two, and the first and second high-pressure fuel pumps 30 and 40 are connected to their downstream ends. The low-pressure fuel discharged from the low-pressure fuel pump 50 is supplied to the first and second high-pressure fuel pumps 30 and 40 via the low-pressure delivery pipe 14 having the above configuration.

  The first and second high-pressure fuel pumps 30 and 40 are positive displacement pumps connected to a crankshaft (not shown) of the engine 3 and are supplied from the low-pressure fuel pump 50 by being driven by the crankshaft. The low-pressure fuel is further pressurized and discharged to the high-pressure delivery pipe 15. Details of the first and second high-pressure fuel pumps 30 and 40 will be described later.

  The upstream end of the high-pressure delivery pipe 15 is connected to the first and second high-pressure fuel pumps 30 and 40, respectively, and once gathered in the one collecting portion 15a in the middle of the downstream side, then further downstream thereof It branches into two on the side and extends into the left and right banks, respectively, and four injectors 4 are provided in parallel at these portions. The high-pressure fuel discharged from the first and second high-pressure fuel pumps 30 and 40 is supplied to each injector 4 via the high-pressure delivery pipe 15 having the above-described configuration, and the corresponding cylinder is opened when the injector 4 is opened. 7 is injected.

  Further, a fuel pressure sensor 21 is provided at the gathering portion 15 a of the high-pressure delivery pipe 15. The fuel pressure sensor 21 detects the fuel pressure (hereinafter referred to as “fuel pressure”) PF in the high-pressure delivery pipe 15, and the detection signal is output to the ECU 2.

  The fuel supply apparatus 10 also includes a first bypass pipe 16a that bypasses the first high-pressure fuel pump 30, and a second bypass pipe 16b that bypasses the second high-pressure fuel pump 30, and the bypass pipes 16a and 16b include Relief valves 17 and 17 are provided, respectively. The relief valve 17 is a mechanical type, and opens when the fuel pressure PF in the high pressure delivery pipe 15 reaches a predetermined relief pressure PREL (for example, 25 MPa), and fuel is supplied from the high pressure delivery pipe 15 to the low pressure delivery pipe 14. The fuel pressure PF is limited so as not to exceed the relief pressure PREL.

  The first and second high-pressure fuel pumps 30 and 40 have the same configuration as each other. Hereinafter, the configuration of the first high-pressure fuel pump 30 will be described with reference to FIGS. . As shown in FIGS. 3 to 5, the first high-pressure fuel pump 30 drives the pump body 31, the suction check valve 32 and the discharge check valve 34 accommodated in the pump body 31, and the suction check valve 32. And a plunger 35 driven by a cam 6 provided on a cam shaft (not shown) of the engine 3.

  A booster chamber 31a for boosting fuel is formed inside the pump body 31, and this booster chamber 31a communicates with the low-pressure delivery pipe 14 via the suction port 31b and via the discharge port 31c. The high pressure delivery pipe 15 communicates. The suction check valve 32 opens and closes the inlet of the boosting chamber 31a, is accommodated in the boosting chamber 31a, and includes a valve body 32a and a coil spring 32b. The valve body 32a is freely movable between a valve opening position for opening the inlet of the pressure increasing chamber 31a (position shown in FIG. 3) and a valve closing position for closing the inlet of the pressure increasing chamber 31a (position shown in FIG. 5). And is biased toward the valve closing position by the coil spring 32b.

  On the other hand, the electromagnetic actuator 33 constitutes a spill valve mechanism together with the suction check valve 32, and includes an actuator body 33a, a coil 33b, an armature 33c, a coil spring 33d, and the like. The coil 33b is accommodated in the actuator body 33a and is electrically connected to the ECU 2. The coil 33b is excited by the drive signal when the drive signal is input from the ECU 2, and is held in a non-excited state when the drive signal is not input.

  In addition, the armature 33c has a predetermined origin position (a position shown in FIGS. 3 and 4) whose tip protrudes toward the suction check valve 32 and a predetermined operating position (a position shown in FIG. 5) retracted from the suction check valve 32 side. The actuator main body 33a accommodates the actuator body 33a so as to be movable between the position and the position. The armature 33c is held at the origin position by the biasing force of the coil spring 33d when the coil 33b is in the non-excited state, and when the coil 33b is excited by the drive signal, the electromagnetic force of the coil spring 33d is It is attracted to the operating position side against the urging force.

  Further, the urging force of the coil spring 33d of the electromagnetic actuator 33 is set to a value larger than the urging force of the coil spring 32b of the suction check valve 32, whereby the suction check valve 32 is in a non-excited state of the coil 33b. At this time, the valve is kept open by the armature 33c at the origin (see FIG. 4).

  On the other hand, the discharge check valve 34 opens and closes the outlet of the boosting chamber 31a, is accommodated in the valve chamber 31d between the boosting chamber 31a and the discharge port 31c, and includes a valve body 34a and a coil spring 34b. ing. The valve body 34a is between a valve opening position (a position shown in FIG. 5) for opening the outlet of the pressure increasing chamber 31a and a valve closing position (a position shown in FIGS. 3 and 4) for closing the outlet of the pressure increasing chamber 31a. While being provided movably, it is biased toward the valve closing position by a coil spring 34b.

  Further, the plunger 35 is located between a predetermined protruding position (a position shown in FIG. 5) at which one end thereof protrudes into the booster chamber 31a and a predetermined retracted position (a position shown in FIG. 3) retracted from the booster chamber 31a. Is slidable in the plunger barrel 31e of the pump body 31. On the other hand, a spring seat 36 is attached to the other end of the plunger 35, and the plunger 35 and the spring seat 36 are in contact with the cam 6 via a spring holder 38.

  Further, a coil spring 37 is provided between the spring seat 36 and the pump body 31, and the plunger 35 is biased toward the retracted position by the coil spring 37. With the above configuration, the plunger 35 is held so as to come into contact with the cam surface of the cam 6 via the spring holder 38 by the urging force of the coil spring 37 during the rotation of the cam 6. The cam 6 is always driven between the protruding position and the retracted position.

  Next, the operation of the first high-pressure fuel pump 30 configured as described above will be described. In the first high-pressure fuel pump 30, the suction stroke, the spill stroke, and the discharge stroke are executed once in order with the rotation of the cam 6 during one operation cycle.

  First, in the suction stroke, as the cam 6 rotates clockwise from the rotation angle position shown in FIG. 5 toward the rotation angle position shown in FIG. 3, the plunger 35 moves from the protruding position to the retracted position. At the same time, the fuel pressure PF in the boosting chamber 31a is lowered, whereby the suction check valve 32 is opened, and the fuel from the low pressure fuel pump 50 is sucked into the boosting chamber 31a.

  In the spill stroke following the suction stroke, the plunger 35 moves from the retracted position toward the protruding position as the cam 6 rotates from the rotation angle position shown in FIG. 3 toward the rotation angle position shown in FIG. At this time, when the electromagnetic actuator 33 is turned off, the suction check valve 32 is held in the open state, whereby the low-pressure fuel in the boosting chamber 31a is returned to the low-pressure fuel pump 50 side.

  In the discharge process following the spill process, the cam 6 rotates from the rotation angle position shown in FIG. 4 toward the rotation angle position shown in FIG. 5 and the electromagnetic actuator 33 is turned on, so that the suction check valve 32 is turned on. Close the valve. As a result, the fuel pressure PF increases, the discharge check valve 34 opens, and the high-pressure fuel in the boosting chamber 31 a is discharged to the high-pressure delivery pipe 15. During this discharge stroke, the electromagnetic actuator 33 is controlled to be in an ON state from the drive start timing TMDRV to a predetermined drive end timing.

  As described above, in the first high-pressure fuel pump 30, the amount of fuel returned from the boosting chamber 31a to the low-pressure fuel pump 50 side is changed by controlling the drive start timing TMDRV of the electromagnetic actuator 33 during the spill stroke. Thereby, the fuel pressure PF in the high-pressure delivery pipe 15 is controlled. The drive start timing TMDRV of the electromagnetic actuator 33 is set in a fuel pressure PF control process described later.

  On the other hand, the crankshaft is provided with a crank angle sensor 22 composed of a magnet rotor and an MRE pickup (both not shown) (see FIG. 2). The crank angle sensor 22 outputs a CRK signal and a TDC signal that are pulse signals as the crankshaft rotates.

  The CRK signal is output every predetermined crank angle (for example, 30 °). The ECU 2 calculates the engine speed (hereinafter referred to as “engine speed”) NE of the engine 3 based on the CRK signal. The TDC signal is a signal indicating that the piston (not shown) of the engine 3 is in a predetermined crank angle position near the TDC (top dead center) at the start of the intake stroke in any cylinder.

  An intake air amount sensor 23 is provided in an intake pipe (not shown) of the engine 3. The intake air amount sensor 23 detects the intake air amount GAIR sucked into the cylinder 7 and outputs a detection signal to the ECU 2.

  The ECU 2 includes a microcomputer (not shown) including a CPU, a RAM, a ROM, an input / output interface (all not shown), and the like. The detection signals of the above-described sensors 21 to 23 are respectively input to the ECU 2, A / D converted and shaped by the input interface, and then input to the CPU. In accordance with these detection signals, the CPU executes various arithmetic processes based on a control program stored in the ROM. In the present embodiment, the ECU 2 corresponds to a high-pressure fuel pump control unit and a failure determination unit.

  Next, the high pressure fuel pump failure determination process executed by the ECU 2 will be described with reference to FIG. This process is executed every predetermined time. This failure determination corresponds to any state of the first and second high-pressure fuel pumps 30 and 40 being normal, overdischarge failure (failure in which fuel is discharged), or non-discharge failure (failure in which fuel cannot be discharged). It is determined for each of the high-pressure fuel pumps 30 and 40 whether or not to do so.

  In this process, first, in step 1 (illustrated as “S1”, the same applies hereinafter), it is determined whether or not the detected fuel pressure PF is equal to the relief pressure PREL of the relief valve 17. When the answer is YES and the fuel pressure PF to be controlled to the target fuel pressure PFCMD is a high value equal to the relief pressure PREL, the fuel pressure PF is excessive, so the first and second high-pressure fuel pumps 30, 40 It is determined that an overdischarge failure has occurred, and the failure pattern 7 flag F_ERR7 is set to “1” to indicate that it corresponds to the failure pattern 7 shown in FIG. 10 (step 2). Exit.

  On the other hand, when the answer to step 1 is NO, it is determined in step 3 whether or not the fuel pressure PF is equal to the feed pressure PFEED of the low-pressure fuel pump 50. If the answer to this question is YES and the fuel pressure PF is a low value equal to the feed pressure PFEED, the fuel pressure PF is too low, so that a non-discharge failure has occurred in the first and second high-pressure fuel pumps 30, 40. The failure pattern 6 flag F_ERR6 is set to “1” in order to indicate that it corresponds to the failure pattern 6 (step 4), and this processing is terminated.

  On the other hand, when the answer to steps 1 and 3 is NO, it is determined that the first and second high-pressure fuel pumps 30 and 40 have not failed due to the same failure pattern. In step 5, the target fuel pressure PFCMD is determined. The difference between the actual fuel pressure PF and the actual fuel pressure PF is calculated as a fuel pressure deviation DPF.

  Next, in Step 6, it is determined whether or not the calculated absolute value | DPF | of the fuel pressure deviation DPF is equal to or less than a predetermined threshold value PREF (for example, 1 MPa). If the answer is NO and | DPF |> PREF, the fuel pressure PF does not follow the target fuel pressure PFCMD well, and therefore a failure has occurred in at least one of the first and second high-pressure fuel pumps 30, 40. In order to identify the failed high-pressure fuel pump and its failure pattern, the second failure determination process is executed in step 7 and this process is terminated.

  FIG. 7 shows the second failure determination process. In this process, first, in step 21, the electromagnetic actuator 43 of the second high-pressure fuel pump 40 (P2) is turned off to stop the fuel discharge from the second high-pressure fuel pump 40 to the high-pressure delivery pipe 15.

  Next, in step 22, it is determined whether or not the value TDP2 of the down-counting type second high-pressure fuel pump stop timer that measures the elapsed time since the second high-pressure fuel pump 40 is stopped is zero. If the answer to this question is NO and a predetermined time T2 (for example, 1 sec) has not elapsed since the second high-pressure fuel pump 40 was stopped, this processing is terminated.

  On the other hand, if the answer to step 22 is YES and the predetermined time T2 has elapsed since the stop of the second high-pressure fuel pump 40, it is determined in step 23 whether the fuel pressure PF is equal to the feed pressure PFEED. When the answer is YES, the absolute value | DPF | of the fuel pressure deviation DPF is larger than the threshold value PREF, and the fuel pressure PF due to the operation of the first high pressure fuel pump 30 is too small. It is determined that a non-ejection failure has occurred, and the failure pattern 2 flag F_ERR2 is set to “1” to indicate that it corresponds to the failure pattern 2 (step 24), and this process ends. .

  On the other hand, when the answer to step 23 is NO, it is determined in step 25 whether or not the fuel pressure PF is equal to the relief pressure PREL. When the answer is YES, the absolute value | DPF | of the fuel pressure deviation DPF is larger than the threshold value PREF, and the fuel pressure PF due to the operation of the first high pressure fuel pump 30 is excessive. It is determined that an over-discharge failure has occurred, and the failure pattern 3 flag F_ERR3 is set to “1” to indicate that it corresponds to failure pattern 3 (step 26), and this process is terminated. .

  On the other hand, when the answer to step 25 is NO, in step 27, the fuel discharge from the second high-pressure fuel pump 40 is restarted, and the electromagnetic actuator 33 of the first high-pressure fuel pump 30 (P1) is turned off. Thus, the fuel discharge from the first high-pressure fuel pump 30 to the high-pressure delivery pipe 15 is stopped, and in steps 28 to 32, the failure determination is made on the second high-pressure fuel pump 40 in the same manner as in steps 22 to 26. I do.

  First, in step 28, it is determined whether or not a value TDP1 of a down-count type first high-pressure fuel pump stop timer that measures an elapsed time since the first high-pressure fuel pump 30 is stopped is zero. If the answer is NO and a predetermined time T1 (for example, 1 sec) has not elapsed since the stop of the first high-pressure fuel pump 30, this process is terminated.

  On the other hand, if the answer to step 28 is YES and the predetermined time T1 has elapsed since the stop of the first high-pressure fuel pump 30, it is determined in step 29 whether or not the fuel pressure PF is equal to the feed pressure PFEED. When the answer is YES, the absolute value | DPF | of the fuel pressure deviation DPF is larger than the threshold value PREF, and the fuel pressure PF due to the operation of the second high pressure fuel pump 40 is too small. It is determined that a non-ejection failure has occurred, and the failure pattern 4 flag F_ERR4 is set to “1” to indicate that it corresponds to the failure pattern 4 (step 30), and this process ends. .

  On the other hand, when the answer to step 29 is NO, it is determined in step 31 whether or not the fuel pressure PF is equal to the relief pressure PREL. When the answer is YES, the absolute value | DPF | of the fuel pressure deviation DPF is larger than the threshold value PREF, and the fuel pressure PF due to the operation of the second high pressure fuel pump 40 is excessive, so that the second high pressure fuel pump 40 It is determined that an over-discharge failure has occurred, and the failure pattern 5 flag F_ERR5 is set to “1” to indicate that it corresponds to the failure pattern 5 (step 32), and this process ends. .

  On the other hand, when the answer to step 31 is NO, the absolute value | DPF | of the fuel pressure deviation DPF is larger than the threshold value PREF, and even if the second high-pressure fuel pump 40 is stopped, the fuel pressure PF is equal to the feed pressure PFEED. Even if the first high-pressure fuel pump 30 is stopped, the fuel pressure PF does not become the feed pressure PFEED or the relief pressure PREL even if the first high-pressure fuel pump 30 is stopped. It is determined that a non-ejection failure has occurred and an over-discharge failure has occurred on the other side, and the failure pattern 8 flag F_ERR8 and the failure pattern 9 flag F_ERR9 are respectively set to “1” to indicate that the failure pattern 8 or 9 corresponds. "(Steps 33 and 34), and this process is terminated.

  Returning to FIG. 6, when the answer to step 6 is YES and | DPF | ≦ PREF, it is determined in step 8 whether or not the fuel pressure feedback value KHPUMP is smaller than a predetermined upper limit value KHPUMPH. This fuel pressure feedback value KHPUMP is calculated by feedback control so that the actual fuel pressure PF becomes the target fuel pressure PFCMD in the control of the fuel pressure PF described later, and the fuel pressure PF tends to be insufficient with respect to the target fuel pressure PFCMD. The larger the value is calculated.

  Therefore, when the answer to step 8 is NO and KHPUMP ≧ KHPUMPH, the fuel pressure PF is too low, and it is assumed that a non-discharge failure has occurred in one of the first and second high-pressure fuel pumps 30 and 40. In order to identify the high-pressure fuel pump in which the non-ejection failure has occurred, the third failure determination process is executed in step 9 and the present process is terminated.

  FIG. 8 shows the third failure determination process. In this process, first, in step 41, the fuel discharge from the second high-pressure fuel pump 40 is stopped, and then in step 42, it is determined whether or not the value TDP2 of the second high-pressure fuel pump stop timer is zero. . If the answer to this question is NO and the predetermined time T2 has not elapsed since the stop of the second high-pressure fuel pump 40, the present process is terminated.

  On the other hand, if the answer to step 42 is YES and the predetermined time T2 has elapsed since the stop of the second high-pressure fuel pump 40, it is determined in step 43 whether or not the fuel pressure PF is equal to the feed pressure PFEED. If the answer is YES, it is determined that a non-discharge failure has occurred in the first high-pressure fuel pump 30, and the failure pattern 2 flag F_ERR2 is set to “1”, assuming that it corresponds to the failure pattern 2 (step 44). ), This process is terminated.

  On the other hand, when the answer to step 43 is NO, in step 45, the fuel discharge from the second high-pressure fuel pump 40 is restarted, and the fuel discharge from the first high-pressure fuel pump 30 to the high-pressure delivery pipe 15 is stopped. At the same time, in steps 46 to 48, a failure determination is made for the second high-pressure fuel pump 40 as in steps 42 to 44.

  First, in step 46, it is determined whether or not the value TDP1 of the first high-pressure fuel pump stop timer is zero. If the answer is NO and the predetermined time T1 has not elapsed since the stop of the first high-pressure fuel pump 30, the present process is terminated.

  On the other hand, if the answer to step 46 is YES and the predetermined time T1 has elapsed since the stop of the first high-pressure fuel pump 30, it is determined in step 47 whether or not the fuel pressure PF is equal to the feed pressure PFEED. If the answer is YES, it is determined that a non-discharge failure has occurred in the second high-pressure fuel pump 40, and the failure pattern 4 flag F_ERR4 is set to “1”, assuming that it corresponds to the failure pattern 4 (step 48). ), This process is terminated.

  On the other hand, when the answer to step 47 is NO, it is determined that a non-discharge failure has occurred in one of the first and second high-pressure fuel pumps 30 and 40, and an over-discharge failure has occurred in the other. As applicable, the failure pattern 8 flag F_ERR8 and the failure pattern 9 flag F_ERR9 are respectively set to “1” (steps 49 and 50), and this process is terminated.

  Returning to FIG. 6, when the answer to step 8 is YES and KHPUMP <KHPUMPH, it is determined in step 10 whether or not the fuel pressure feedback value KHPUMP is greater than a predetermined lower limit value KHPUMPL.

  If the answer to step 10 is NO and KHPUMP ≦ KHPUMPL, the fuel pressure PF is excessive, and it is assumed that an overdischarge failure has occurred in one of the first and second high pressure fuel pumps 30, 40. In order to identify the high-pressure fuel pump in which the discharge failure has occurred, a fourth failure determination process is executed in step 11 and this process is terminated.

  FIG. 9 shows the fourth failure determination process. In this process, first, in step 61, the second high-pressure fuel pump 40 is stopped, and then in step 62, it is determined whether or not the value TDP2 of the second high-pressure fuel pump stop timer is zero. If the answer to this question is NO and the predetermined time T2 has not elapsed since the stop of the second high-pressure fuel pump 40, the present process is terminated.

  On the other hand, if the answer to step 62 is YES and the predetermined time T2 has elapsed since the stop of the second high-pressure fuel pump 40, it is determined in step 63 whether or not the fuel pressure PF is equal to the relief pressure PREL. If the answer is YES, it is determined that an overdischarge failure has occurred in the first high-pressure fuel pump 30, and the failure pattern 3 flag F_ERR3 is set to “1”, assuming that it corresponds to the failure pattern 3 (step 64). ), This process is terminated.

  On the other hand, when the answer to step 63 is NO, in step 65, the discharge of fuel from the second high-pressure fuel pump 40 is resumed, and the discharge of fuel from the first high-pressure fuel pump 30 to the high-pressure delivery pipe 15 is stopped. At the same time, in Steps 66 to 68, the failure determination is performed on the second high-pressure fuel pump 40 as in Steps 62 to 64.

  First, in step 66, it is determined whether or not the value TDP1 of the first high-pressure fuel pump stop timer is zero. If the answer to this question is NO and the predetermined time T1 has not elapsed since the stop of the first high-pressure fuel pump 30, the present process is terminated.

  On the other hand, if the answer to step 66 is YES and the predetermined time T1 has elapsed since the stop of the first high-pressure fuel pump 30, it is determined in step 67 whether or not the fuel pressure PF is equal to the relief pressure PREL. If the answer is YES, it is determined that an overdischarge failure has occurred in the second high-pressure fuel pump 40, and the failure pattern 5 flag F_ERR5 is set to “1”, assuming that it corresponds to the failure pattern 5 (step 68). ), This process is terminated.

  On the other hand, if the answer to step 67 is NO, it is determined that one of the first and second high-pressure fuel pumps 30 and 40 has a non-discharge failure and the other has an over-discharge failure. As applicable, the failure pattern 8 flag F_ERR8 and the failure pattern 9 flag F_ERR9 are each set to “1” (steps 69 and 70), and this process is terminated.

  Returning to FIG. 6, when the answer to step 10 is YES and KHPUMPL <KHPUMP <KHPUMPH, the fuel pressure feedback value KHPUMP is within a predetermined range, so both the first and second high-pressure fuel pumps 30 and 40 are normal. In addition to determining that there is a failure pattern 1, the failure pattern 1 flag F_ERR1 is set to “1” to indicate that the failure pattern 1 is present (step 12), and this processing is terminated.

  As described above, in the failure determination process of the high-pressure fuel pump in FIG. 6 described above, first, failure determination of the first and second high-pressure fuel pumps 30 and 40 is performed according to the fuel pressure PF due to the operation of both the high-pressure fuel pumps 30 and 40. (Steps 1 to 4). If it is not determined as a failure in this failure determination, the failure determination of the first and second high-pressure fuel pumps 30 and 40 is sequentially performed according to the absolute value | DPF | of the fuel pressure deviation DPF (steps 5 to 7). Further, when it is not determined that there is a failure in these failure determinations, the failure determination of the first and second high-pressure fuel pumps 30 and 40 is sequentially performed according to the magnitude of the fuel pressure feedback value KHPUMP. By executing such a failure determination, it is possible to identify the high-pressure fuel pump and the failure pattern that have failed.

  FIG. 11 shows the control process of the fuel pressure PF. In this process, first, in step 81, a target fuel pressure PFCMD is calculated by searching a predetermined map according to the detected engine speed NE and intake air amount GAIR. In this map, the target fuel pressure PFCMD is set to a larger value as the intake air amount GAIR is larger.

  Next, in step 82, the difference between the target fuel pressure PFCMD and the actual fuel pressure PF is calculated as a fuel pressure deviation DPF.

  Next, in step 83, the P term KHPPX of the fuel pressure feedback value KHPUMP is calculated by searching a predetermined map according to the calculated fuel pressure deviation DPF. In this map, the P term KHPPX is set to a larger value as the fuel pressure deviation DPF is larger.

  Next, in step 84, the fuel pressure deviation integrated value ΣDPF is calculated by adding the fuel pressure deviation DPF to the fuel pressure deviation integrated value ΣDPF calculated so far.

  Next, in step 85, an I-term gain KHPISUMX is calculated by searching a predetermined map according to the fuel pressure deviation DPF.

  Next, in step 86, the I term KHPIX is calculated by multiplying the calculated I term gain KHPISUMX by the fuel pressure deviation integrated value ΣDPF calculated in step 84.

  Next, at step 87, a fuel injection amount QINJ is calculated by searching a predetermined map according to the engine speed NE and the intake air amount GAIR. In this map, the fuel injection amount QINJ is set to a larger value as the engine speed NE is higher and the intake air amount GAIR is larger.

  Next, in step 88, the basic value KHPFF of the fuel pressure feedback value KHPUMP is calculated by searching a predetermined map according to the calculated fuel injection amount QINJ. In this map, the basic value KHPFF is set to a larger value as the fuel injection amount QINJ is larger.

  Next, at step 89, the fuel pressure feedback value KHPUMP is calculated by adding the P term KHPPX and the I term KHPIX to the calculated basic value KHPFF.

  Next, in step 90, by searching a predetermined map according to the calculated fuel pressure feedback value KHPUMP, the drive start timing TMDRV of the electromagnetic actuators 33 and 43 is calculated, and this process is terminated. In this map, the drive start timing TMDRV is set to be earlier as the fuel pressure feedback value KHPUMP is larger. Then, when the electromagnetic actuators 33 and 43 are driven at the set drive start timing TMDRV, the fuel pressure PF is controlled to converge to the target fuel pressure PFCMD.

  As described above, according to the present embodiment, when the absolute value | DPF | of the fuel pressure deviation DPF is larger than the threshold value PREF, the failure determination of the first high-pressure fuel pump 30 is executed (step 6 in FIG. 6). 7 and FIG. 7), the failure determination of the first high-pressure fuel pump 30 can be performed at an appropriate timing.

  Prior to this failure determination, since the operation of the second high-pressure fuel pump 40 is stopped (step 21 in FIG. 7), the failure determination of the first high-pressure fuel pump 30 is appropriately performed without being affected by the operation. be able to. Further, when the fuel pressure PF reaches the relief pressure PREL, it is determined that an overdischarge failure has occurred in the first high-pressure fuel pump 30 (steps 25 and 26 in FIG. 7), and the fuel pressure PF has decreased to the feed pressure PFEED. Sometimes, it is determined that a non-discharge failure has occurred in the first high-pressure fuel pump 30 (steps 23 and 24 in FIG. 7), so that any of the over-discharge failure and the non-discharge failure has occurred. The failure of the first high-pressure fuel pump 30 can be appropriately determined while specifying the failure pattern.

  When it is determined that no failure has occurred in the first high-pressure fuel pump 30, the operation of the first high-pressure fuel pump 30 is stopped and the operation of the second high-pressure fuel pump 40 is resumed (step 27 in FIG. 7). Later, the failure of the second high-pressure fuel pump 40 is determined by the same method as the above-described failure determination of the first high-pressure fuel pump 30 (steps 28 to 34 in FIG. 7). Accordingly, the failure determination of the second high-pressure fuel pump 40 can be made appropriately while specifying the failure pattern without being affected by the operation of the first high-pressure fuel pump 30, and the first and second high-pressure fuel pumps 30, 40 can be determined. It is possible to clearly identify which of the failure has occurred.

  Further, when the absolute value | DPF | of the fuel pressure deviation DPF is equal to or smaller than the threshold value PREF and the fuel pressure feedback value KHPUMP is not in the range of KHPUMPL <KHPUMP <KHPUMPH, the failure determination is executed (steps 9 and 11 in FIG. 6). 8 and 9), whether or not the failure determination is necessary based on the magnitude of the fuel pressure feedback value KHPUMP even when the failure of the first and second high pressure fuel pumps 30 and 40 does not clearly appear as the fuel pressure deviation DPF. (Steps 8 and 12 in FIG. 6), the failure of the high-pressure fuel pump 30 can be executed at a more appropriate timing.

  In addition, this invention can be implemented in various aspects, without being limited to the described embodiment. For example, in the embodiment, the fuel supply apparatus 10 includes the two high-pressure fuel pumps 30 and 40. However, the number of the high-pressure fuel pumps may be three or more as long as they are provided in parallel to each other.

  In the embodiment, the first and second high-pressure fuel pumps 30 and 40 are positive displacement types connected to the crankshaft of the engine 3, but are not limited thereto, and are electric types such as the low-pressure fuel pump 50. It may be.

  In the embodiment, as shown in FIG. 1, the high pressure delivery pipe 15 once gathers in one collecting portion 15a on the downstream side of the first and second high pressure fuel pumps 30 and 40, and then on the downstream side thereof. Although it is configured to branch again into two, it only needs to communicate with each other between the downstream sides of both high-pressure fuel pumps 30 and 40. For example, as shown in FIG. 12, the first and second high-pressure fuels The high pressure delivery pipes 15 and 15 extending from the pumps 30 and 40, respectively, may be connected by a communication pipe 15b.

  Further, in the embodiment, the engine 3 is a V-type 8-cylinder type having banks independent from each other, but high-pressure fuel discharged from the high-pressure fuel pump is supplied to each injector 4 via the high-pressure delivery pipe 15. As long as it is configured to be supplied, it may not be an independent bank but may be a single cylinder.

  In the embodiment, the fuel pressure feedback value KHPUMP for controlling the fuel pressure PF to the target fuel pressure PFCMD is calculated using the basic value KHPFF and the feedback term (P term KHPPX, I term KHPIX). You may calculate only by.

  The embodiment is an example in which the present invention is applied to a gasoline engine mounted on a vehicle, but the present invention is not limited to this, and may be applied to various engines such as a diesel engine other than a gasoline engine. Also, the present invention can be applied to engines other than those for vehicles, for example, engines for marine propulsion devices such as outboard motors having a crankshaft arranged vertically. In addition, it is possible to appropriately change the detailed configuration within the scope of the gist of the present invention.

1 High pressure fuel pump failure determination device 2 ECU (high pressure fuel pump control means, failure determination means)
3 Engine (Internal combustion engine)
4 Injector (fuel injection valve)
7 cylinder 10 fuel supply system (fuel supply system)
11 Fuel tank 14 Low pressure delivery pipe (low pressure fuel supply passage)
15 High pressure delivery pipe (High pressure fuel supply passage)
16a First bypass pipe (bypass passage)
16b Second bypass pipe (bypass passage)
17 Relief valve 21 Fuel pressure sensor (fuel pressure detection means)
30 First High Pressure Fuel Pump 40 Second High Pressure Fuel Pump 50 Low Pressure Fuel Pump PF Fuel Pressure PFCMD Target Fuel Pressure | DPF | Absolute value (deviation) of fuel pressure deviation
DREF threshold value PREL relief pressure (relief valve opening pressure)
PFEED Feed pressure KHPUMP Fuel pressure feedback value (feedback value)

Claims (3)

A failure determination device for a high-pressure fuel pump that determines failure of a first high-pressure fuel pump and a second high-pressure fuel pump that are provided in parallel to a fuel supply system that supplies fuel to a fuel injection valve that injects fuel into a cylinder. ,
A low-pressure fuel pump that boosts the fuel in the fuel tank to a predetermined feed pressure;
A low-pressure fuel supply passage for supplying low-pressure fuel discharged from the low-pressure fuel pump to the first and second high-pressure fuel pumps;
A high-pressure fuel supply passage for supplying high-pressure fuel discharged from the first and second high-pressure fuel pumps to the fuel injection valve;
Fuel pressure detection means for detecting the fuel pressure in the high-pressure fuel supply passage as fuel pressure;
A bypass passage for bypassing the first and second high pressure fuel pumps;
A relief valve that is provided in the bypass passage and opens when the fuel pressure exceeds a predetermined valve opening pressure, and allows the fuel to escape from the high-pressure fuel supply passage to the low-pressure fuel supply passage;
High-pressure fuel pump control means for feedback-controlling the first and second high-pressure fuel pumps so that the detected fuel pressure becomes a predetermined target fuel pressure;
When the deviation between the fuel pressure and the target fuel pressure is greater than a predetermined threshold value, the second high pressure fuel pump is stopped, and the fuel pressure is reduced when the second high pressure fuel pump is stopped. When the valve opening pressure is reached, it is determined that an overdischarge failure occurs while the fuel is discharged to the first high pressure fuel pump, and the fuel pressure is reduced to the predetermined feed pressure of the low pressure fuel pump. A failure determination means for determining that a non-discharge failure incapable of discharging fuel has occurred in the first high-pressure fuel pump;
A failure determination device for a high-pressure fuel pump, comprising:   The failure determination means stops the operation of the first high pressure fuel pump and determines the failure of the second high pressure fuel pump when it is determined that no failure has occurred in the first high pressure fuel pump. The failure determination device for a high-pressure fuel pump according to claim 1, wherein   The failure determination means performs failure determination when a deviation between the fuel pressure and the target fuel pressure is equal to or less than the threshold value and a feedback value set in the feedback control is not within a predetermined range. The failure determination device for a high-pressure fuel pump according to claim 1 or 2.

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