JP2016211477A - Injection control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection control device that can continue operation of an internal combustion engine even when part of a high-side switch for supplying a drive current to a fuel injection valve is broken.SOLUTION: In an injection control device 10, a first high-side switch HSW1 and a third high-side switch HSW3 are connected to each other via a first switch SW1 and a second high-side switch HSW2 and the third high-side switch HSW3 are connected to each other via a second switch SW2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an injection control device that controls a fuel injection valve of an internal combustion engine.

  Each of the plurality of cylinders of the internal combustion engine is provided with a fuel injection valve (injector) for injecting fuel and supplying it into the cylinder. The fuel injection valve is an electromagnetic valve that opens and closes by operating an internal valve body when supplied with a driving current. When the fuel injection valve is opened, fuel injection is started, and when the fuel injection valve is closed, fuel injection is stopped. The injection control device is a device for performing fuel injection control in an internal combustion engine by controlling the opening / closing operation of a fuel injection valve provided for each cylinder (see, for example, Patent Document 1 below).

  Each of the fuel injection valves is connected to a low side switch for driving the fuel injection valve and switching its opening and closing. When the low side switch is closed, a driving current is supplied to the fuel injection valve connected to the low side switch, and the fuel injection valve is opened to inject fuel. When the low side switch is in the open state, the supply of drive current to the fuel injection valve connected to the low side switch is stopped, the fuel injection valve is closed, and fuel injection is stopped.

  Each fuel injection valve is connected to a high-side switch for switching between supply and cutoff of drive current. Similarly to the low-side switch, one high-side switch may be connected to each of a plurality of fuel injection valves. However, one of the high-side switches may be connected to a plurality of fuel injection valves from the viewpoint of reducing component costs.

JP 2005-180217 A

  When some of the high-side switches provided are broken, the drive current is not supplied to the fuel injection valve connected to the high-side switch, and the corresponding cylinder stops operating. It becomes. In particular, when a high-side switch connected to a plurality of fuel injection valves fails, a plurality of cylinders stop operating simultaneously. For example, in an internal combustion engine having three cylinders, if two or more cylinders stop operating at the same time due to a failure of the high side switch, the internal combustion engine cannot continue to operate.

  The present invention has been made in view of such problems, and its purpose is to operate the internal combustion engine even when a part of the high-side switch for supplying a drive current to the fuel injection valve fails. An object of the present invention is to provide an injection control device that can be continued.

  In order to solve the above problems, an injection control device according to the present invention is an injection control device that controls a fuel injection valve provided for each cylinder of an internal combustion engine, and is a switch for driving the fuel injection valve. A plurality of injection valve low-side switches provided corresponding to the respective fuel injection valves, and one of the fuel injection valves connected to the fuel injection valve for supplying and shutting off the drive current A first high-side switch for switching between and a plurality of fuel injection valves different from the fuel injection valve to which the first high-side switch is connected, and supply of drive current to the plurality of fuel injection valves And a second high-side switch for switching between cutoff and a low-side switch provided separately for driving at least one injection control actuator other than the fuel injection valve. When, and a third high side switch for switching between supply and cutoff of the drive current for the injection control actuator. The first high side switch and the third high side switch are connected via the first switch, and the second high side switch and the third high side switch are connected via the second switch. Yes.

  In the injection control device having such a configuration, for example, even when the first high-side switch fails and the drive current is not supplied to some of the fuel injection valves, A driving current from the third high-side switch can be supplied via the first switch. Similarly, even if the second high-side switch fails and no drive current is supplied to some of the fuel injection valves, the fuel injection valves are connected to the third high-side switch via the second switch. A driving current can be supplied from the side switch.

  For this reason, even after the first high-side switch or the like fails, the operation of all the fuel injection valves can be continued, whereby the operation of the internal combustion engine can be continued.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where a part of high side switch which supplies the electric current for a drive to a fuel injection valve fails, the injection control apparatus which can continue operation | movement of an internal combustion engine is provided.

It is a figure which shows typically the structure of the injection control apparatus which concerns on embodiment of this invention. It is a figure which shows the state of the injection control apparatus when the 2nd high side switch fails. It is a figure which shows the state of the injection control apparatus when the 1st high side switch fails. It is a figure which shows the state of the injection control apparatus when both the 1st high side switch and the 2nd high side switch fail. It is a figure which shows the state of the injection control apparatus when a 3rd high side switch fails. It is a time chart which shows typically the change of the output state of the drive current supplied to each 1st injector etc. from each high side switch. It is a time chart which shows typically the change of the output state of the drive current supplied to each 1st injector etc. from each high side switch. It is a time chart which shows typically the change of the output state of the drive current supplied to each 1st injector etc. from each high side switch. It is a time chart which shows typically the change of the output state of the drive current supplied to each 1st injector etc. from each high side switch. It is a time chart which shows typically the change of the output state of the drive current supplied to each 1st injector etc. from each high side switch. It is a time chart which shows typically the change of the output state of the drive current supplied to each 1st injector etc. from each high side switch. It is a time chart which shows typically the change of the output state of the drive current supplied to each 1st injector etc. from each high side switch. It is a flowchart which shows the flow of the process performed with the injection control apparatus shown by FIG. It is a flowchart which shows the flow of the process performed with the injection control apparatus shown by FIG. It is a flowchart which shows the flow of the process performed with the injection control apparatus shown by FIG. It is a flowchart which shows the flow of the process performed with the injection control apparatus shown by FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same constituent elements in the drawings will be denoted by the same reference numerals as much as possible, and redundant description will be omitted.

  An injection control device 10 according to an embodiment of the present invention will be described with reference to FIG. The injection control device 10 is configured as an injection control device for controlling fuel injection in an internal combustion engine (not shown) of a vehicle.

  Specifically, the internal combustion engine includes three cylinders, and one injector (first injector IJ1, second injector IJ2, third injector IJ3) that is a fuel injection valve is provided for each cylinder. Yes. The injection control device 10 controls the operation of each of these three injectors. The configurations of the first injector IJ1, the second injector IJ2, and the third injector IJ3 are all the same. Hereinafter, these three injectors are also collectively referred to as “first injector IJ1 etc.”.

  The first injector IJ1 and the like receive fuel supplied from a common rail CR provided in the vehicle and inject the fuel into each cylinder. The common rail CR is a pressure accumulating container for storing fuel whose fuel pressure is increased by the operation of the fuel pump FP which is one of the injection control actuators, and supplying the fuel to the first injector IJ1 and the like.

  The fuel pump FP is a pump for pressurizing the fuel stored in a fuel tank (not shown) provided in the vehicle and feeding it into the common rail CR. The common rail CR is provided with a pressure reducing valve RPV which is one of the injection control actuators. The pressure reducing valve RPV is an electromagnetic valve for appropriately maintaining the pressure in the common rail CR by returning a part of the fuel in the common rail CR to the fuel tank. The injection control device 10 controls the operations of the fuel pump FP and the pressure reducing valve RPV in addition to controlling the fuel injection from the first injector IJ1 and the like.

  When a drive current is supplied from the injection control device 10 to the first injector IJ1, etc., the internal valve body moves to open the valve, and fuel injection is started. Further, when the supply of the driving current is stopped, the internal valve body returns to the original position and the valve is closed, and the fuel injection is stopped.

  The configuration of the injection control device 10 will be described. As shown in FIG. 1, the injection control apparatus 10 includes three high-side switches (first high-side switch HSW1, second high-side switch HSW2, third high-side switch HSW3) and five low-side switches (first A low-side switch LSW1, a second low-side switch LSW2, a third low-side switch LSW3, a fourth low-side switch LSW4, and a fifth low-side switch LSW5), a first switch SW1, and a second switch SW2.

  The first high-side switch HSW1 is a switch for switching between supply and cutoff of the drive current to the third injector IJ3. When the first high-side switch HSW1 is turned on (closed state), a driving current can be supplied to the third injector IJ3 via the power supply path PL1. However, the drive current actually flows through the third injector IJ3 when a later-described third low-side switch LSW3 is turned on. During normal operation (when the vehicle is running normally; the same applies hereinafter), the first high-side switch HSW1 remains on.

  The second high side switch HSW2 is a switch for switching between supply and cutoff of the drive current to both the first injector IJ1 and the second injector IJ2. When the second high side switch HSW2 is turned on, a driving current can be supplied to both the first injector IJ1 and the second injector IJ2 via the power supply path PL2. However, the drive current actually flows through the first injector IJ1 when a later-described first low-side switch LSW1 is turned on. Similarly, the drive current actually flows through the second injector IJ2 when a later-described second low-side switch LSW2 is turned on. During normal operation, the second high-side switch HSW2 remains on.

  The third high side switch HSW3 is a switch for switching between supply and cutoff of the drive current to both the pressure reducing valve RPV and the fuel pump FP. When the third high-side switch HSW3 is turned on, a driving current can be supplied to both the pressure reducing valve RPV and the fuel pump FP via the power supply path PL3. However, the drive current actually flows through the pressure reducing valve RPV (the pressure reducing valve RPV is opened and the pressure in the common rail CR is reduced) is when a later-described fourth low-side switch LSW4 is turned on. . Similarly, the drive current actually flows through the fuel pump FP (the fuel pump FP is driven and the fuel is supplied to the common rail CR) when a later-described fifth low-side switch LSW5 is turned on. is there. During normal operation, the third high side switch HSW3 remains on.

  The power supply path PL2 extending from the second high-side switch HSW2 branches in the middle, and one of the branches is connected to the first injector IJ1, and the other is connected to the second injector IJ2. The first low-side switch LSW1 is provided at a position opposite to the second high-side switch HSW2 across the first injector IJ1 in the power supply path PL2 extending from the branch point to the first injector IJ1 side. It is a switch (MOSFET). The injection control device 10 controls the fuel injection (injection timing and injection amount) from the first injector IJ1 to the cylinder by opening and closing the first low-side switch LSW1 at a predetermined timing and duty.

  The second low-side switch LSW2 is provided at a position opposite to the second high-side switch HSW2 across the second injector IJ2 in the power supply path PL2 extending from the branch point to the second injector IJ2 side. It is a switch (MOSFET). The injection control device 10 controls the fuel injection (injection timing and injection amount) from the second injector IJ2 to the cylinder by opening and closing the second low side switch LSW2 at a predetermined timing and duty.

  The third low-side switch LSW3 is a switch (MOSFET) provided at a position opposite to the first high-side switch HSW1 across the third injector IJ3 in the power supply path PL1 extending from the first high-side switch HSW1. It is. The injection control device 10 controls the fuel injection (injection timing and injection amount) from the third injector IJ3 to the cylinder by opening and closing the third low-side switch LSW3 at a predetermined timing and duty.

  The power supply path PL3 extending from the third high-side switch HSW3 branches in the middle, and one of the branches is connected to the pressure reducing valve RPV, and the other is connected to the fuel pump FP. The fourth low-side switch LSW4 is a switch provided at a position opposite to the third high-side switch HSW3 across the pressure reducing valve RPV in the power supply path PL3 extending from the branch point to the pressure reducing valve RPV side. MOSFET). The injection control device 10 controls the operation of the pressure reducing valve RPV by opening and closing the fourth low-side switch LSW4 at a predetermined timing and duty, thereby adjusting the pressure in the common rail CR.

  The fifth low-side switch LSW5 is a switch provided at a position on the opposite side of the third high-side switch HSW3 across the fuel pump FP in the power supply path PL3 extending from the branch point to the fuel pump FP side. MOSFET). The injection control device 10 controls the operation of the fuel pump FP, that is, the supply of fuel to the common rail CR, by opening and closing the fifth low-side switch LSW5 at a predetermined timing and duty.

  The first switch SW1 includes a portion of the power supply path PL1 that is closer to the first high-side switch HSW1 than the third injector IJ3, and a portion of the power supply path PL3 that is closer to the third high-side switch HSW3 than the pressure reducing valve RPV. , A switch provided on a path connecting the two. The operation of the first switch SW1 is controlled by the injection control device 10. The first switch SW1 is always in an off state (open state) during normal operation.

  The second switch SW2 is a portion of the power supply path PL2 that is closer to the second high side switch HSW2 than the first injector IJ1 and the like, and a portion of the power supply path PL3 that is closer to the third high side switch HSW3 than the fuel pump FP. And a switch provided on a path connecting the two. The operation of the second switch SW2 is controlled by the injection control device 10. The second switch SW2 is always in an off state (open state) during normal operation.

  The other structure of the injection control apparatus 10 is demonstrated. A first diode D1 is provided at a position closer to the first high-side switch HSW1 than the first switch SW1 in the power supply path PL1. The first diode D1 allows the driving current to flow from the first high-side switch HSW1 side to the first switch SW1 side, and suppresses the driving current from flowing from the first switch SW1 side to the first high-side switch HSW1 side. Is provided.

  A second diode D2 is provided at a position closer to the second high-side switch HSW2 than the second switch SW2 in the power supply path PL2. The second diode D2 allows the driving current to flow from the second high side switch HSW2 side to the second switch SW2 side, and suppresses the driving current from flowing from the second switch SW2 side to the second high side switch HSW2 side. Is provided.

  As already described, during the normal operation, both the first switch SW1 and the second switch SW2 are always off. In such a state, the injection control device 10 controls fuel injection from the first injector IJ1 and the like by switching opening and closing of the first low-side switch LSW1 and the like. Further, the operation of the pressure reducing valve RPV is controlled by switching the opening and closing of the fourth low-side switch LSW4. Further, the operation of the fuel pump FP is controlled by switching the opening and closing of the fifth low-side switch LSW5.

  In the injection control apparatus 10 according to the present embodiment, even when the second high-side switch HSW2 or the like, which is a drive current supply source, fails (hereinafter referred to as "abnormal"), the first injector IJ1 or the like is sent. It is possible to continue supplying the driving current. An outline of the control executed by the injection control device 10 at the time of abnormality will be described with reference to FIGS.

  FIG. 2 is a diagram illustrating a state of the injection control device 10 when the second high side switch HSW2 fails. If the second high-side switch HSW2 fails and cannot supply the driving current, the second switch SW2 is switched on as shown in FIG.

  In the state of FIG. 2, the driving current from the third high-side switch HSW3 is also supplied to the first injector IJ1 and the second injector IJ2 via the second switch SW2. As a result, even if the second high-side switch HSW2 is in a failure state, the operation of all (three) cylinders provided in the vehicle can be continued.

  FIG. 3 is a diagram illustrating a state of the injection control device 10 when the first high-side switch HSW1 fails. When the first high-side switch HSW1 fails and cannot supply the driving current, the first switch SW1 is switched on as shown in FIG.

  In the state of FIG. 3, the driving current from the third high-side switch HSW3 is also supplied to the third injector IJ3 via the first switch SW1. As a result, even if the first high-side switch HSW1 is in a failure state, the operation of all (three) cylinders included in the vehicle can be continued.

  FIG. 4 is a diagram illustrating a state of the injection control device 10 when both the first high-side switch HSW1 and the second high-side switch HSW2 have failed. When the first high-side switch HSW1 and the second high-side switch HSW2 fail and cannot supply the drive current, as shown in FIG. 3, both the first switch SW1 and the second switch SW2 Is also switched on.

  In the state of FIG. 4, the driving current from the third high-side switch HSW3 is also supplied to the third injector IJ3 via the first switch SW1. Further, the driving current from the third high side switch HSW3 is also supplied to the first injector IJ1 and the second injector IJ2 via the second switch SW2. As a result, even if both the first high-side switch HSW1 and the second high-side switch HSW2 are in a failure state, the operation of all (three) cylinders included in the vehicle can be continued.

  FIG. 5 is a diagram illustrating a state of the injection control device 10 when the third high side switch HSW3 fails. If the third high-side switch HSW3 fails and cannot supply the driving current, the first switch SW1 is switched on as shown in FIG.

  In the state of FIG. 5, the driving current from the first high-side switch HSW1 is also supplied to the pressure reducing valve RPV and the fuel pump FP via the first switch SW1. As a result, even if the third high side switch HSW3 is in a failure state, the operations of the pressure reducing valve RPV and the fuel pump FP can be continued.

  When the third high-side switch HSW3 fails, the second switch SW2 may be switched on instead of the first switch SW1. In this case, the driving current from the second high side switch HSW2 is also supplied to the pressure reducing valve RPV and the fuel pump FP via the second switch SW2.

  By the way, when a driving current is supplied from the first high side switch HSW1 or the like to the third injector or the like, electric power is stored (charged) in the first high side switch HSW1 or the like in advance. Thereby, a high voltage is applied to a coil such as a third injector, and the third injector and the like are opened and closed at an appropriate timing.

  For example, in the case shown in FIG. 3, the driving current from one third high-side switch HSW3 is supplied not only to the pressure reducing valve RPV and the fuel pump FP but also to the third injector IJ3. If supply of drive current to the third injector and supply of drive current to the pressure reducing valve RPV, etc. are performed at the same time, a part of the accumulated power is supplied to the pressure reducing valve RPV and the like. Therefore, the voltage applied to the coil of the third injector IJ3 may be lower than normal. In that case, there is a concern that the timing and opening of the third injector IJ3 change, and the fuel injection amount and injection timing become inappropriate.

  A device for preventing such a phenomenon will be described with reference to FIGS. FIG. 6 shows changes in the output state of the driving current supplied from the high-side switches (the first high-side switch HSW1, the second high-side switch HSW2, and the third high-side switch HSW3) to the first injector IJ1 and the like. It is a time chart which shows typically.

  In FIG. 6, the time chart with the reference “HSW1” shows the output state of the driving current output from the first high-side switch HSW1. The time chart is drawn so that the low side switch (the third low side switch LSW3 and the like) connected to the downstream side of the first high side switch HSW1 is Hi when it is closed and Lo when it is open. Yes.

  For example, when the third low-side switch LSW3 is closed and the driving current from the first high-side switch HSW1 is supplied to the third injector IJ3, the time chart becomes Hi. Also, when the first switch SW1 is closed and the fourth low-side switch LSW4 is closed, and the driving current from the first high-side switch HSW1 is supplied to the pressure reducing valve RPV, the time chart is Hi. Become. Further, when the first switch SW1 is closed and the fifth low-side switch LSW5 is closed, and the driving current from the first high-side switch HSW1 is supplied to the fuel pump FP, the time chart is Hi. Become.

  In FIG. 6, the time chart denoted by “HSW2” shows the output state of the driving current output from the second high-side switch HSW2. The time chart is drawn so that the low side switch (the first low side switch LSW1 and the like) connected to the downstream side of the second high side switch HSW2 is Hi when it is closed, and Lo when it is open. Yes.

  For example, when the first low-side switch LSW1 or the second low-side switch LSW2 is in a closed state and the driving current from the second high-side switch HSW2 is supplied to the first injector IJ1 or the second injector IJ2, the time chart is Hi. Further, when the second switch SW2 is closed and the fourth low-side switch LSW4 is closed, and the driving current from the second high-side switch HSW2 is supplied to the pressure reducing valve RPV, the time chart shows Hi. Become. Further, when the second switch SW2 is closed and the fifth low-side switch LSW5 is closed, and the driving current from the second high-side switch HSW2 is supplied to the fuel pump FP, the time chart is Hi. Become.

  In the present embodiment, fuel injection from the first injector IJ1 or the like is performed a plurality of times in one combustion stroke. That is, a so-called “multi-stage injection” is performed. In FIG. 6, a waveform indicating the output state of the drive current during a period in which the opening / closing operation of the first low-side switch LSW1 is performed (a period in which multistage injection from the first injector IJ1 is performed) is shown as a waveform IJP1. Similarly, a waveform indicating the output state of the driving current during a period during which the opening / closing operation of the second low-side switch LSW2 is performed (a period during which multistage injection from the second injector IJ2 is performed) is shown as a waveform IJP2. A waveform indicating the output state of the drive current during a period during which the opening / closing operation of the third low-side switch LSW3 is performed (a period during which multistage injection from the third injector IJ3 is performed) is shown as a waveform IJP3.

  In FIG. 6, the time chart with the reference “HSW3” shows the output state of the driving current output from the third high-side switch HSW3. The time chart is drawn so that the low side switch (the fourth low side switch LSW4, etc.) connected to the downstream side of the third high side switch HSW3 is Hi when it is closed, and Lo when it is open. Yes.

  For example, when the fourth low-side switch LSW4 or the fifth low-side switch LSW5 is closed and the driving current from the third high-side switch HSW3 is supplied to the pressure reducing valve RPV or the fuel pump FP, the time chart is Hi. Become. The time chart is also Hi when the first switch SW1 is closed and the third low-side switch LSW3 is closed and the driving current from the third high-side switch HSW3 is supplied to the third injector IJ3. It becomes. Furthermore, the second switch SW2 is closed and the first low-side switch LSW1 or the second low-side switch LSW2 is closed, and the driving current from the third high-side switch HSW3 is supplied to the first injector IJ1 or the second injector IJ2. The time chart is Hi even when

  In FIG. 6, a waveform indicating the output state of the driving current in a period in which the opening / closing operation of the fourth low-side switch LSW4 is performed (a period in which pressure reduction by the pressure reducing valve RPV is performed) is shown as a waveform RP. Further, a waveform indicating the output state of the driving current during a period during which the fifth low-side switch LSW5 is opened and closed (a period during which fuel supply by the fuel pump FP is performed) is shown as a waveform PP.

  The time chart at the bottom of FIG. 6 shows the change in the number (injector number) indicating the injector where fuel injection is performed. When the injector number is 1, fuel injection is performed from the first injector IJ1. When the injector number is 2, fuel injection is performed from the second injector IJ2. When the injector number is 3, fuel injection is performed from the third injector IJ3.

  Switching of the injector to be injected, that is, switching of the injector number is performed according to the change of the crank angle. In the example shown in FIG. 6, the injector number is 1 during the period in which the crank angle is within the range CA1. In the period when the crank angle exceeds the range CA1 and is within the range CA2, the injector number is 2. In the period when the crank angle exceeds the range CA2 and is within the range CA3, the injector number is 3. When the crank angle exceeds the range CA3, the crank angle again falls within the range CA1, and the injector number becomes 1. The ranges CA1, CA2, and CA3 are all 240 ° (720 ° / 3) angular ranges.

  7 to 12 referred to in the following description also show time charts similar to the time charts of FIG. 6 described above.

  The example shown in FIG. 6 is for normal operation. The first switch SW1 and the second switch SW2 are both open. Therefore, the drive current (waveform IJP1) to the first injector IJ1 is supplied from the second high side switch HSW2, and the drive current (waveform IJP2) to the second injector IJ2 is also supplied from the second high side switch HSW2. The drive current (waveform IJP3) to the third injector IJ3 is supplied from the first high-side switch HSW1. Further, the driving current (waveform RP) to the pressure reducing valve RPV is supplied from the third high side switch HSW3, and the driving current (waveform PP) to the fuel pump FP is also supplied from the third high side switch HSW3.

  Further, the required load on the internal combustion engine at this time is relatively small, and the output of the internal combustion engine is also small. Accordingly, the amount of fuel injected from the first injector IJ1 and the like is decreasing.

  For this reason, in the example shown in FIG. 6, the range of the waveform IJP1 or the like, that is, the period during which the fuel is injected from the first injector IJ1 or the like is relatively short. As a result, the period in which the waveform IJP1 and the like are generated does not overlap with the period in which the waveforms RP and PP are generated.

  The example shown in FIG. 7 is during normal operation as in FIG. Also in FIG. 7, both the first switch SW1 and the second switch SW2 are open. However, in the example of FIG. 7, the required load on the internal combustion engine is relatively large, and the output of the internal combustion engine is also large. Accordingly, the amount of fuel injected from the first injector IJ1 and the like is increasing.

  For this reason, in the example shown in FIG. 7, the range of the waveform IJP1 or the like, that is, the period during which fuel is injected from the first injector IJ1 or the like is relatively long. As a result, the period in which the waveform IJP1 and the like occur and the period in which the waveforms RP and PP occur partially overlap each other.

  For example, when the crank angle is within the range CA3, the period during which the drive current is supplied to the third injector IJ3 (waveform IJP3) and the period during which the drive current is supplied to the pressure reducing valve RPV (waveform) RP) overlap each other. However, a driving current is supplied to the third injector IJ3 and the pressure reducing valve RPV from separate high-side switches. Therefore, the applied voltage does not decrease as described above, and an appropriate driving current is supplied to both the third injector IJ3 and the pressure reducing valve RPV.

  On the other hand, for example, in the state shown in FIG. 3 (the state in which the first high-side switch HSW1 is out of order), the required load of the vehicle increases, and at the timing shown in FIG. When the driving current is supplied, the driving current from the third high side switch HSW3 is supplied to both the third injector IJ3 and the pressure reducing valve RPV at the same time.

  Therefore, in the injection control device 10 according to the present embodiment, when the first high-side switch HSW1 fails and the first switch SW1 is in the closed state, even when the required load on the vehicle is large, the internal combustion engine The output (torque) is limited.

  The example shown in FIG. 8 is an example in which the first high-side switch HSW1 has failed as described above and the first switch SW1 is in the closed state. At this time, as already described with reference to FIG. 3, the driving current is supplied to the third injector IJ3 from the third high-side switch HSW3. For this reason, the waveform IJP3 in FIG. 8 is drawn not in the time chart labeled “HSW1” but in the time chart labeled “HSW3”.

  At this time, the required load of the vehicle is large as in the case of FIG. 7, but the output of the internal combustion engine is limited in the example of FIG. For this reason, the range of the waveform IJP1 or the like, that is, the period during which fuel is injected from the first injector IJ1 or the like is relatively short as in the example of FIG. As a result, the period in which the waveform IJP3 occurs and the period in which the waveforms RP and PP occur do not overlap each other. There is no period during which the drive current from the third high-side switch HSW3 is supplied to both the third injector IJ3 and the pressure reducing valve RPV (and the fuel pump FP) at the same time. For this reason, an appropriate driving current is supplied to all of the third injector IJ3, the pressure reducing valve RPV, and the fuel pump FP. The time chart when the required load of the vehicle is small is the same as the time chart shown in FIG.

  The same applies to the case where the second high side switch HSW2 fails. The example shown in FIG. 9 is an example when the second high-side switch HSW2 is out of order and the second switch SW2 is in the closed state. At this time, as already described with reference to FIG. 2, the drive current is supplied to the first injector IJ1 and the second injector IJ2 from the third high-side switch HSW3. For this reason, the waveform IJP1 and the waveform IJP2 in FIG. 9 are drawn not in the time chart with the symbol “HSW2” but with the time chart with the symbol “HSW3”.

  At this time, the required load of the vehicle is large as in the case of FIG. 7, but the output of the internal combustion engine is limited in the example of FIG. For this reason, the range of the waveform IJP1 or the like, that is, the period during which fuel is injected from the first injector IJ1 or the like is relatively short as in the example of FIG. As a result, the period in which the waveforms IJP1, IJP2 are generated and the period in which the waveforms RP, PP are generated do not overlap each other. There is no period during which the drive current from the third high-side switch HSW3 is supplied to both the first injector IJ1 and the like and the pressure reducing valve RPV (and the fuel pump FP) at the same time. For this reason, an appropriate driving current is supplied to any of the first injector IJ1, the second injector IJ2, the pressure reducing valve RPV, and the fuel pump FP. The time chart when the required load of the vehicle is small is the same as the time chart shown in FIG.

  The example shown in FIG. 10 is an example in which both the first high-side switch HSW1 and the second high-side switch HSW2 are out of order and both the first switch SW1 and the second switch SW2 are closed. It is. At this time, as already described with reference to FIG. 4, the drive current is supplied from the third high-side switch HSW3 to the first injector IJ1, the second injector IJ2, and the third injector IJ3. . For this reason, the waveform IJP1, the waveform IJP2, and the waveform IJP3 in FIG. 10 are not time charts with the symbol “HSW1” or time charts with the symbol “HSW2”, but times with the symbol “HSW3”. It is drawn on the chart.

  Also in the example of FIG. 10, the output of the internal combustion engine is limited. For this reason, the range of the waveform IJP1 or the like, that is, the period during which fuel is injected from the first injector IJ1 or the like is relatively short as in the example of FIG. As a result, the periods in which the waveforms IJP1, IJP2, and IJP3 are generated do not overlap with the periods in which the waveforms RP and PP are generated. There is no period during which the drive current from the third high-side switch HSW3 is supplied to both the first injector IJ1 and the like and the pressure reducing valve RPV (and the fuel pump FP) at the same time. Therefore, an appropriate driving current is supplied to any of the first injector IJ1, the second injector IJ2, the third injector IJ3, the pressure reducing valve RPV, and the fuel pump FP. The time chart when the required load of the vehicle is small is the same as the time chart shown in FIG.

  The example shown in FIG. 11 is an example when the third high-side switch HSW3 is out of order and the first switch SW1 is closed. At this time, as already described with reference to FIG. 5, the drive current is supplied to the pressure reducing valve RPV and the fuel pump FP from the first high-side switch HSW1. For this reason, the waveform RP and the waveform PP in FIG. 11 are drawn not in the time chart labeled “HSW3” but in the time chart labeled “HSW1”.

  In the example of FIG. 11 as well, the output of the internal combustion engine is limited. For this reason, the range of the waveform IJP1 or the like, that is, the period during which fuel is injected from the first injector IJ1 or the like is relatively short as in the example of FIG. As a result, the period in which the waveform IJP3 occurs and the period in which the waveforms RP and PP occur do not overlap each other. There is no period during which the drive current from the first high-side switch HSW1 is supplied to both the third injector IJ3 and the pressure reducing valve RPV (and the fuel pump FP) at the same time. For this reason, an appropriate driving current is supplied to all of the third injector IJ3, the pressure reducing valve RPV, and the fuel pump FP. The time chart when the required load of the vehicle is small is the same as the time chart shown in FIG.

  By the way, when the pressure reducing valve RPV breaks down, the pressure in the common rail CR cannot be adjusted (reduced). Therefore, in the injection control device 10, the pressure in the common rail CR is lowered by performing idle driving with the first injector IJ 1 or the like.

  A return path (not shown) for returning the fuel in the injector to the fuel tank is formed between the first injector IJ1 and the like and the fuel tank. In addition, a piston for switching opening and closing of the inlet of the return path is disposed inside the first injector IJ1 and the like.

  The idle driving means that the fuel inside the first injector IJ1 and the like is caused to flow into the return path (return to the fuel tank) by operating only the piston without changing the position of the valve body (needle). If such idle driving is performed, the fuel in the common rail CR is returned to the fuel tank not via the pressure reducing valve RPV but via the first injector IJ1 (and the return path). As a result, the pressure in the common rail CR can be reduced.

  FIG. 12 shows a time chart when the above-described idle driving is performed. In FIG. 12, the waveform indicating the output state of the driving current during the period in which the first low-side switch LSW1 is opened and closed and the first injector IJ1 is idle is shown as a waveform IJP11. In addition, a waveform indicating the output state of the driving current during a period in which the second low-side switch LSW2 is opened and closed so that the second injector IJ2 is idle is shown as a waveform IJP12. Similarly, the waveform indicating the output state of the driving current during the period when the third low-side switch LSW3 is opened and closed and the third injector IJ3 is idled is shown as a waveform IJP13.

  As shown in FIG. 12, the idle shot (waveform IJP11 etc.) in each of the first injectors IJ1 etc. is performed every time following the multistage injection of fuel (waveform IJP1 etc.). For this reason, the pressure in the common rail CR is appropriately adjusted as in the case where the pressure reducing valve RPV is operating normally (FIG. 6).

  Also in the example of FIG. 12, the output of the internal combustion engine is limited. As a result, a period for performing idling is ensured between a period during which fuel multi-stage injection is performed (waveform IJP1 and the like) and a period during which fuel pump FP is driven (waveform PP). Yes.

  A specific flow of processing executed by the injection control device 10 in order to cope with failure of the first high-side switch HSW1 and the like as described above will be described. FIG. 13 is a flowchart showing the flow of the processing. A series of processes shown in FIG. 13 are repeatedly executed at a predetermined cycle by a microcomputer (not shown) included in the injection control device 10.

  In the first step S100, it is determined whether or not fuel injection in each of the first injectors IJ1 and the like is normally performed. If fuel injection is normally performed in all the first injectors IJ1, etc., it means that both the first high-side switch HSW1 and the second high-side switch HSW2 are operating normally. In this case, the series of processing shown in FIG. 13 is terminated without switching the first switch SW1 and the like.

  In step S100, if fuel injection is not normally performed by any of the first injectors IJ1, etc., the process proceeds to step S200. In this case, it is estimated that a failure has occurred in either the first high-side switch HSW1 or the second high-side switch HSW2. There is also a possibility that a failure has occurred in the first injector IJ1 or the like.

  In step S200, countermeasures are taken according to the failure that has occurred. The specific contents will be described with reference to FIG. The flowchart in FIG. 14 shows the specific contents of the process performed in step S200 in FIG.

  The types of failures that can occur in the first high-side switch HSW1 and the like include an OPEN failure, a GND short failure, and the like. The OPEN failure is a failure in which a disconnection occurs between the first high-side switch HSW1 or the like and the first injector IJ1 or the like, and the driving current cannot be supplied to the first injector IJ1 or the like.

  The GND short-circuit failure means that a part of the power supply path PL1 extending from the first high-side switch HSW1 etc. and the ground line are short-circuited, so that the drive current cannot be supplied to the first injector IJ1 etc. again. It is such a failure.

  In addition to the OPEN failure and the GND short failure as described above, the failure of the first high-side switch HSW1 etc. makes it impossible to cut off the drive current (the drive current continues to be supplied). ) Can also occur. However, when such a failure occurs, the first switch SW1 and the like are not switched in this embodiment, and the same measures as in the normal state are taken. In the following description, “failure” occurring in the first high-side switch HSW1 or the like indicates an OPEN failure or a GND short failure.

  When only the first high-side switch HSW1 has failed and the second high-side switch HSW2 has not failed, the process proceeds from step S201 in FIG. 14 to step S203 through step S202. In step S203, the output of the internal combustion engine is limited as described with reference to FIG. As a result, the period in which the waveform IJP3 occurs and the period in which the waveforms RP and PP occur do not overlap each other.

  In step S204 following step S203, the first switch SW1 is switched on. As a result, the drive current from the third high-side switch HSW3 is also supplied to the third injector IJ3 via the first switch SW1 (FIG. 3).

  If both the first high-side switch HSW1 and the second high-side switch HSW2 are out of order, the process proceeds from step S201 to step S205 through step S202. In step S205, the output of the internal combustion engine is limited as described with reference to FIG. As a result, the periods in which the waveforms IJP1, IJP2, and IJP3 are generated and the periods in which the waveforms RP and PP are generated do not overlap each other.

  In step S206 following step S205, both the first switch SW1 and the second switch SW2 are switched on. As a result, the drive current is supplied from the third high-side switch HSW3 (FIG. 4) to the first injector IJ1, the second injector IJ2, and the third injector IJ3.

  When only the second high-side switch HSW2 has failed and the first high-side switch HSW1 has not failed, the process proceeds from step S201 to step S207 to step S208. In step S208, the output of the internal combustion engine is limited as described with reference to FIG. As a result, the period in which the waveforms IJP1 and IJP2 are generated and the period in which the waveforms RP and PP are generated do not overlap each other.

  In step S209 following step S208, the second switch SW2 is switched on. As a result, the driving current from the third high-side switch HSW3 is also supplied to the first injector IJ1 and the second injector IJ2 via the second switch SW2 (FIG. 2).

  If no failure has occurred in either the first high-side switch HSW1 or the second high-side switch HSW2 (step S207: No), the first switch SW1 and the second switch SW2 are not switched. The series of processes shown in FIG. In this case, since one of the first injector IJ1, the second injector IJ2, and the third injector IJ3 is presumed to be out of order, an abnormality corresponding to the failure (for example, transition to the retreat travel mode) is performed. Will be.

  In parallel with the processes of FIGS. 13 and 14 described above, the microcomputer of the injection control apparatus 10 repeatedly executes the processes shown in FIGS. 15 and 16.

  The process shown in FIG. 15 is a process for dealing with a failure of the third high-side switch HSW3. If the third high-side switch HSW3 is not malfunctioning (step S301: No), the series of processes shown in FIG. 15 is terminated. When the third high-side switch HSW3 is out of order, the process proceeds from step S301 to step S302.

  In step S302, the output of the internal combustion engine is limited as described with reference to FIG. As a result, the period in which the waveform IJP3 occurs and the period in which the waveforms RP and PP occur do not overlap each other.

  In step S303 following step S302, the first switch SW1 is switched on. As a result, the driving current from the first high-side switch HSW1 is also supplied to the pressure reducing valve RPV and the fuel pump FP via the first switch SW1 (FIG. 5).

  The process shown in FIG. 16 is a process for dealing with a failure of the pressure reducing valve RPV. If the pressure reducing valve RPV has not failed (step S401: No), the series of processes shown in FIG. 16 is terminated. When the pressure reducing valve RPV is out of order, the process proceeds from step S401 to step S402.

  In step S402, the output of the internal combustion engine is limited as described with reference to FIG. As a result, a period for performing idling is ensured between a period during which fuel multi-stage injection is performed (waveform IJP1 and the like) and a period during which fuel pump FP is driven (waveform PP). It becomes a state.

  In step S403 subsequent to step S402, idle driving is executed by the first injector IJ1 or the like. Thereby, the pressure in the common rail CR is adjusted to be appropriate.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In other words, those specific examples that have been appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. For example, the elements included in each of the specific examples described above and their arrangement, materials, conditions, shapes, sizes, and the like are not limited to those illustrated, but can be changed as appropriate. Moreover, each element with which each embodiment mentioned above is provided can be combined as long as technically possible, and the combination of these is also included in the scope of the present invention as long as it includes the features of the present invention.

10: Injection control device HSW1: First high side switch HSW2: Second high side switch HSW3: Third high side switch LSW1: First low side switch LSW2: Second low side switch LSW3: Third low side switch LSW4: Fourth low side switch LSW5: fifth low side switch SW1: first switch SW2: second switch

Claims (8)

An injection control device that controls a fuel injection valve (IJ1, IJ2, IJ3) provided for each cylinder of an internal combustion engine,
A switch for driving the fuel injection valve, and a plurality of low side switches (LSW1, LSW2, LSW3) for injection valves provided individually corresponding to the fuel injection valves;
A first high-side switch (HSW1) connected to one of the fuel injectors for switching between supply and shut-off of drive current to the fuel injector;
The first high-side switch is connected to a plurality of the fuel injection valves different from the fuel injection valve to which the first high-side switch is connected, and a first for switching between supplying and shutting off the drive current to the plurality of fuel injection valves. 2 high-side switch (HSW2),
A low-side switch individually provided for driving at least one injection control actuator other than the fuel injection valve;
A third high-side switch for switching between supply and interruption of drive current to the injection control actuator,
The first high side switch and the third high side switch are connected via a first switch (SW1),
The injection control apparatus, wherein the second high side switch and the third high side switch are connected via a second switch (SW2).   The injection control actuator includes at least one of a fuel pump (FP) for supplying fuel to each of the fuel injection valves via a common rail and a pressure reducing valve (PRV) provided on the common rail. The injection control device according to claim 1, wherein:   In the normal state in which all of the first high-side switch, the second high-side switch, and the third high-side switch are operating normally, both the first switch and the second switch are open. The injection control device according to claim 1 or 2, wherein When the first high-side switch fails and cannot supply the driving current, the first switch is closed.
4. The injection control device according to claim 3, wherein the second switch is closed when the second high-side switch has failed and cannot supply a drive current. 5. . When at least one of the first high-side switch or the second high-side switch fails and is unable to supply a driving current,
In a period different from the period during which the injection control actuator is driven
The injection control apparatus according to claim 4, wherein the fuel injection valve connected to the failed one of the first high-side switch and the second high-side switch is driven. When at least one of the first high-side switch or the second high-side switch fails and is unable to supply a driving current,
The injection control device according to claim 5, wherein an output of the internal combustion engine is limited.   When the third high-side switch fails and is unable to supply a driving current, at least one of the first switch and the second switch is closed. The injection control device according to claim 1.   In the injection control actuator, when the pressure reducing valve fails and the pressure in the common rail cannot be reduced, the fuel injection valve performs the idle driving, so that the fuel in the common rail is reduced. The injection control device according to claim 2, wherein a part is returned to the fuel tank.

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