JP6504091B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention is directed to a fuel injection valve that controls an internal combustion engine and injects fuel into a combustion chamber of the internal combustion engine, and a secondary side by stopping energization of the primary coil after energizing the primary coil. The present invention relates to a control device for an internal combustion engine that operates an ignition device that discharges an ignition plug connected to a coil.

  For example, Patent Document 1 describes a control device that realizes restart processing after automatic stop processing of an internal combustion engine by fuel cut processing by starting fuel injection in a cylinder in a compression stroke. In this control device, the injection timing and the ignition timing of the cylinder in the compression stroke are set independently.

  Further, there is known a technology for performing automatic stop processing of an internal combustion engine by fuel cut processing at the time of deceleration of a vehicle, in which case ignition control is continued to burn unburned fuel in the combustion chamber during fuel cut processing. The technology is well known. Then, in that case, the injection timing of the first fuel injection after the restart of the fuel injection from the fuel cut and the ignition timing performed during the fuel cut processing are set independently.

Patent No. 3661762

  When the injection timing and the ignition timing are set independently of each other as described above, ignition is performed before the end of fuel injection, and combustion is started before fuel and air are mixed well. There is a concern that abnormal combustion may occur. In particular, when the ignition control is performed during the fuel cut process, the ignition timing does not take into consideration the injection timing, and thus the ignition may be performed before the end of the fuel injection.

  The present invention has been made in view of such circumstances, and its object is to provide an internal combustion engine capable of suppressing ignition in the middle of the first fuel injection when fuel injection is resumed after fuel cut processing. It is in providing a control device of an engine.

  A control device for an internal combustion engine to solve the above problems is an internal combustion engine as a control target, and a fuel injection valve that injects fuel into a combustion chamber of the internal combustion engine, and a primary side coil after energization of the primary side coil. And a control device for an internal combustion engine that operates an ignition device that discharges an ignition plug connected to a secondary coil by stopping energization of the secondary coil, and operating the fuel injection valve to inject the fuel into the combustion chamber. When a fuel cut process is performed to stop injection of the fuel when the injection processing unit and the crankshaft of the internal combustion engine are rotating, a fuel cut time point at which the ignition device is operated to discharge the spark plug With the fire processing unit and the fuel cut processing being performed, the injection processing unit requests the fuel injection by the injection processing unit to resume injection of the fuel. The injection period acquisition processing unit acquires the injection period information of the fuel from the injection processing unit when resuming the injection control, and the fuel cut ignition when the injection processing unit resumes the control of injecting the fuel. Based on the injection period information, the end timing of the injection of the fuel by the injection processing unit and the energization time of the primary coil regardless of whether the processing unit performs the energization processing of the primary coil or not. The primary coil is energized until a timing that is later than the timing that has elapsed from the time of resumption of control for injecting the fuel by the required minimum value of the current is delayed, and the energization of the primary coil is performed at the later timing. And a self-ignition ignition processing unit for stopping.

  When fuel injection is resumed when the primary side coil is energized by the fuel cut time ignition processing unit, the primary side coil may not be energized during injection and ignition may occur due to the ignition device. is there. In this respect, in the above configuration, since the primary start coil is energized by at least the end of injection of fuel by the ignition processing unit for autonomous start, ignition is performed in the middle of the first fuel injection when fuel injection is resumed after fuel cut processing. Can be suppressed.

The figure which shows one Embodiment of the control apparatus of an internal combustion engine, and an internal combustion engine. (A) And (b) is a time chart which shows the processing by the ignition processing part at the time of fuel cut. (A) And (b) is a time chart which shows the problem of the process by the ignition processing part at the time of fuel cut. The flowchart which shows the processing procedure of ignition control at the time of return from fuel cut processing. The time chart which shows the feasible region of the ignition processing for autonomous starting. (A) shows the waveform of an operation signal, (b) is a time chart which shows the valve opening timing of the injection valve. (A1), (b1), (a2), (b2) is a time chart which shows the setting of the current supply period according to the injection signal.

Hereinafter, an embodiment according to a control device for an internal combustion engine will be described with reference to the drawings.
An internal combustion engine 10 shown in FIG. 1 is mounted on a vehicle and is the only prime mover that powers drive wheels in the vehicle. Air taken in from the intake passage 12 of the internal combustion engine 10 is taken into the combustion chamber 20 defined by the cylinder 16 and the piston 18 as the intake valve 14 is opened. In the combustion chamber 20, the spark plug 48 of the igniter 22 is exposed. In the combustion chamber 20, the injection hole of the fuel injection valve 24 is exposed. The fuel injection valve 24 is supplied with fuel whose pressure is adjusted by the fuel pump 26.

  A mixture of the air taken in from the intake passage 12 and the fuel injected from the fuel injection valve 24 is supplied to the combustion by the spark discharge of the spark plug 48. The combustion energy of the mixture is converted to rotational energy of the crankshaft 28 via the piston 18. The crankshaft 30 is mechanically connected to a starter 30 for providing the crankshaft 28 with an initial rotation. The air-fuel mixture supplied to the combustion in the combustion chamber 20 is discharged to the exhaust passage 34 as exhaust as the exhaust valve 32 is opened.

  The igniter 22 includes an ignition coil 40 in which a primary coil 40a and a secondary coil 40b are magnetically coupled. In addition, the black circle mark given to one of each pair of terminals of the primary side coil 40a and the secondary side coil 40b of a figure has open | released the both ends of the primary side coil 40a and the secondary side coil 40b. In the state, when the magnetic flux linking them is changed, there is shown a terminal where the polarities of electromotive force generated in each of the primary coil 40a and the secondary coil 40b become equal.

  The spark plug 48 is connected to one terminal of the secondary coil 40 b, and the other terminal is grounded via the diode 44 and the resistor 46. The diode 44 is a rectifying element that allows the flow of current from the spark plug 48 to the ground via the secondary coil 40 b and restricts the flow of current on the opposite side. On the other hand, a switching element 42 for opening and closing a loop circuit including the primary coil 40a and a power supply (not shown) is connected to the primary coil 40a.

  According to such a configuration, when the switching element 42 is closed, the primary coil 40a is energized, and at this time, a voltage is induced in the secondary coil 40b such that the anode side of the diode 44 becomes negative, No current flows to the spark plug 48. On the other hand, when the switching element 42 is switched from the closed state to the open state, a voltage in which the anode side of the diode 44 becomes positive is induced in the secondary coil 40b, thereby causing spark discharge in the spark plug 48. .

  The crankshaft 28 is coupled to a timing rotor 50 provided with tooth portions 52 which indicate a plurality of rotational angles of the crankshaft 28 respectively. Although the timing rotor 50 is basically provided with the teeth 52 at an interval of 10 ° CA, there is a single missing tooth 54 which is a location where the spacing between adjacent teeth 52 is 30 ° CA. It is provided. This is to indicate the reference rotation angle of the crankshaft 28.

  The control device 60 controls the internal combustion engine 10, outputs the operation signals MS1 to MS3 to the fuel injection valve 24, the fuel pump 26, and the ignition device 22, and operates the various actuators to operate the internal combustion engine 10. Control amount (torque, exhaust component) of The control device 60 controls the injection amount NPC of the fuel injection valve 24 detected by the fuel pressure sensor 70 when controlling the control amount, the operation amount of the accelerator pedal detected by the accelerator sensor 72 (acceleration operation amount ACCP), crank The output signal Sca of the angle sensor 74 is referred to. Then, for example, while variably setting the target value of the injection pressure NPC, the control device 60 operates the fuel pump 26 so as to feedback control the injection pressure NPC to the target value. The control device 60 outputs the operation signal MS4 to the starter 30 to start the starter 30, and applies the initial rotation to the crankshaft 28 on the condition that the start request for the internal combustion engine 10 is generated.

  The controller 60 includes a central processing unit (CPU 62) and a memory 64. FIG. 1 shows a part of processing realized by the CPU 62 executing a program stored in the memory 64. The injection processing unit M10 generates and outputs an operation signal MS1 of the fuel injection valve 24 based on the rotation speed NE calculated based on the output signal Sca of the crank angle sensor 74, the load, and the injection pressure NPC. Specifically, the operation signal is obtained by grasping, based on the injection pressure NPC, an appropriate injection period to make the amount of fuel injected from the fuel injection valve 24 equal to the injection amount calculated based on the rotational speed NE and the load. Generate MS1. The load may be, for example, an operation amount of the accelerator pedal.

  The fuel cut-time ignition processing unit M12 is configured to perform an automatic stop process of the internal combustion engine 10 during a fuel cut process, which is performed as a so-called idle stop process, when unburned fuel in the combustion chamber 20 when the crankshaft 28 is rotating. Outputs an operation signal MS3 to the igniter 22 to burn the fuel.

  FIG. 2 shows the ignition processing by the fuel-cut ignition processing unit M12. In FIG. 2, the cylinder numbers which become compression top dead center are described as # 1, # 2, # 3, and # 4. 2A shows the transition of the operation signal MS1, and FIG. 2B shows the transition of the operation state of the switching element 42. As shown in FIG. In FIG. 2B, when the switching element 42 is in the on state is the energization period of the primary side coil 40a, and the timing at which the switching element 42 is switched from the on state to the off state is the ignition timing. When the crankshaft 28 is in the stop state during energization of the primary coil 40a, the energization may be stopped when the energization time reaches a predetermined value.

  As shown in FIG. 2, when the automatic stop process (fuel cut process) is executed based on the fact that the vehicle is predicted to stop at the time of deceleration of the vehicle at time t1, the operation signal MS1 is turned off thereafter. The injection of fuel from the fuel injection valve 24 is stopped. However, in this case, the primary coil 40a is energized before and after the compression top dead center in each cylinder by the fuel cut ignition processing unit M12, and the spark discharge of the spark plug 48 is retarded on the retardation side of the compression top dead center. Generate Thus, the unburned fuel in the combustion chamber 20 is supplied to the combustion.

  In the present embodiment, if, for example, the accelerator pedal is depressed before the rotational speed NE becomes zero and a restart request occurs while the fuel cut processing is being performed, the starter 30 is not activated if possible. The fuel cut recovery process is executed only by the fuel injection. However, in this case, as shown in FIG. 3, when fuel injection is resumed, there is a possibility that ignition may be performed during fuel injection from the fuel injection valve 24.

  FIGS. 3 (a) and 3 (b) correspond to FIGS. 2 (a) and 2 (b), respectively. As shown in FIG. 3, after the automatic stop processing is started at time t1, when a restart request is generated at time t2, so-called autonomous start is performed to start the internal combustion engine 10 only by fuel injection without starting the starter 30. In order to do this, fuel injection is performed from the compression stroke to the expansion stroke. For this reason, a situation may occur where fuel is still injected at time t3, which is the ignition timing set by the fuel cut time ignition processing unit M12. In this case, the abnormal combustion may not completely burn the fuel and the PM generation rate may increase, which may deteriorate the exhaust components or may cause deterioration of the fuel injection valve 24.

Therefore, in the present embodiment, the occurrence of such a situation is minimized by the process shown in FIG.
The process shown in FIG. 4 is realized by the CPU 62 executing a program stored in the memory 64. The process shown in FIG. 4 is executed with the start of fuel injection as the restart process.

  In the series of processes shown in FIG. 4, the CPU 62 first acquires injection period information of the fuel injection that has triggered the process shown in FIG. 4 (S10). This process is a process of acquiring the injection period set by the injection processing unit M10. Next, the CPU 62 determines whether an execution condition of the ignition processing for autonomous starting is satisfied (S12). The execution condition is that the logical sum of the following (a) and (b) is true.

  (A) The start timing of fuel injection accompanying the restart is in the region A before the compression top dead center (denoted as TDC in the drawing) shown in FIG. 5 and the crankshaft 28 is not reversely rotating. This condition is on the condition that it is considered that the execution of the autonomous start does not promote the reverse rotation. The reverse rotation of the crankshaft 28 can be detected, for example, by providing the crank angle sensor 74 with a plurality of detection means arranged at mutually different positions in the circumferential direction of the timing rotor 50, and tooth portions by these respective detection means It may be implemented by a known technique using 52 detected values.

  (B) The start timing of the fuel injection accompanying the restart should be in the region B after the compression top dead center shown in FIG. Note that after compression top dead center, the force applied to the piston 18 by the combustion of fuel does not cause the crankshaft 28 to rotate in the reverse direction, so that "the crankshaft 28 is not rotating in the reverse direction" is not included in the requirement.

  When it is determined that the execution condition is satisfied (S12: YES), the CPU 62 sets an energization time of the primary coil 40a for autonomous start (S14). Specifically, the CPU 62 sets the energization time to the longer one of the time Ttot from the injection start command to the end of the injection and the necessary minimum value of the energization time of the primary side coil 40a. Here, the necessary minimum value is the minimum value of the time required to store in the ignition coil 40 the energy that causes the spark plug 48 to generate the spark discharge necessary for ignition. Further, time Ttot is a time shown in FIG.

  FIG. 6 (a) shows the transition of the operation signal MS1, and FIG. 6 (b) shows the open period (injection period) of the fuel injection valve 24. As shown in FIG. As shown in FIG. 6, even after the injection command to the fuel injection valve 24 is completed by switching the operation signal MS1 from the on state to the off state, the response delay of the fuel injection valve 24 causes the nozzle needle to be in the open state. Therefore, the valve closing timing is delayed with respect to the timing at which the operation signal MS1 is switched to the off state. Therefore, the time Ttot from the injection start command to the end of the injection is the sum of the injection command period Ton and the delay time Tofs.

  Returning to FIG. 4, the CPU 62 next determines whether or not the primary coil 40a is energized (S16). This process is a process of determining whether or not the fuel cut ignition processing unit M12 is performing the energization of the primary side coil 40a. Then, when it is determined that the power is not being supplied (S16: NO), the CPU 62 immediately starts the power supply processing of the primary side coil 40a and executes power supply for the power supply time set by the processing of step S14 (S18). . This process is shown in FIG. 7 (a1) and FIG. 7 (b1).

  FIG. 7 (a1) shows the transition of the operation signal MS1, and FIG. 7 (b1) shows the transition of the state of the switching element 42. In this example, the switching element 42 is off before the notification that the operation signal MS1 is switched to the on state is received, but the switching element 42 is turned on in response to the notification. Incidentally, this example is an example in which the time Ttot from the injection start command to the end of the injection is set as the energization time by the process of step S14.

  Referring back to FIG. 4, when the CPU 62 determines that power is being supplied (S 16: YES), the power supply to the primary coil 40 a is continued and the time until the primary coil 40 a has been supplied is Regardless of the length, the energization is continued only for the energization time set by the process of step S14 from the current time (S20). FIG. 7 (a2) and FIG. 7 (b2) show this process.

  FIG. 7 (a2) shows the transition of the operation signal MS1, and FIG. 7 (b2) shows the transition of the state of the switching element 42. In this example, the switching element 42 is on before the notification that the operation signal MS1 has been switched to the on state, and the switching element 42 continues to be on even after receiving the notification. Incidentally, this example is an example in which the time Ttot from the injection start command to the end of the injection is set as the energization time by the process of step S14.

  Referring back to FIG. 4, when determining that the execution condition is not satisfied (S12: NO), the CPU 62 starts the starter 30 and executes the ignition processing at normal time (S22). Here, the ignition processing at normal time is performed as follows.

  First, in the normal ignition process, the ignition timing is variably set to a value in the range of 30 ° CA (BTDC) to 25 ° CA (ATDC). On the other hand, as shown in FIG. 1, the output signal Sca of the crank angle sensor 74 is a periodic pulse signal at every 10.degree. CA except at the time of detection of the missing tooth portion 54. In particular, compression top dead center (in FIG. , TDC) correspond to predetermined pulse signals. Further, timing T1 in FIG. 1 corresponds to timing on the advanced side of 60 ° CA from compression top dead center, so-called 60 ° CA (BTDC), and timing T2 is 30 ° on the advance side of compression top dead center , Corresponding to the so-called 30 ° CA (BTDC).

  Since the pulse signal does not necessarily coincide with the ignition timing, the CPU 62 controls the ignition timing by the delay time from the specific pulse signal of the output signal Sca. Specifically, when the ignition timing is set between 30 ° CA (BTDC) and TDC, the delay time from the timing T2 to the ignition timing is set based on the time from the timing T1 to the timing T2, and the output signal After the timing T2 is detected by Sca, when the delay time elapses, the switching element 42 is switched to the open state. When the ignition timing is on the retard side of TDC, the delay time from TDC to the ignition timing is set based on the time from T2 to TDC, and after TDC is detected by the output signal Sca, the delay time is set. Switches the switching element 42 to the open state. When the ignition timing is set to TDC, the ignition timing is set in synchronization with the output signal Sca corresponding to TDC.

  However, when the energization processing of the primary side coil 40a is performed by the fuel cut ignition processing unit M12, the above-described ignition processing in the normal state is not performed, and the ignition processing unit M12 is subjected to the energization processing by the fuel cut time. Therefore, the end timing of the energization processing illustrated in FIG. 2 is the ignition timing.

When the processes of steps S18, S20, and S22 are completed, the CPU 62 temporarily ends the series of processes shown in FIG.
Incidentally, after executing the ignition processing for autonomous starting which is the processing of steps S14 to S20, the CPU 62 executes the ignition processing at the normal time. However, the number of times of execution of the ignition process for autonomous starting accompanying the restart request is not limited to one or less. For example, when the rotational speed NE of the crankshaft 28 after execution of the ignition processing for autonomous starting by the processing of FIG. 4 is low to a certain extent, the series of processing shown in FIG. Then, the injection timing may be set on the retard side as compared with that at the normal start, and the same processing as steps S14 to S20 may be performed again.

Here, the operation and effect of the present embodiment will be described.
The CPU 62 executes the fuel cut processing to automatically stop the internal combustion engine 10 as the vehicle decelerates, and then, when a restart request is generated, the condition that the execution condition of the ignition processing for autonomous start is satisfied (S12) Execute the ignition process for autonomous start. Then, the spark plug 48 is discharged after the end of the fuel injection and at a timing as close as possible to the end timing. Thereby, the restart processing of the internal combustion engine 10 can be executed without starting the starter 30. In addition, since the primary coil 40a is energized at least until the end of the fuel injection, it is possible to suppress the ignition from being performed during the first fuel injection that is executed along with the start of the fuel injection from the fuel injection stop state.

According to the present embodiment described above, the following effects can be obtained.
(1) When the fuel injection is started before the compression top dead center in response to the restart request and the reverse rotation of the crankshaft 28 is detected, the normal ignition processing is performed. In the normal ignition process, when the ignition timing is more advanced than TDC, the delay time from the timing T2 is set based on the time from the timing T1 to the timing T2, so the delay time is set to the crankshaft 28 It will be set when rotating forward. Therefore, after the reverse rotation is detected, the delay time is not set until the forward rotation is confirmed, which means that the ignition is not performed. For this reason, even if it is determined that the reverse rotation of the crankshaft 28 is detected and the execution condition is not satisfied in step S12 of FIG. It is possible to suppress the occurrence of a situation where the forward rotation of the

<Correspondence relationship>
Correspondence between the items described in the section “Means for Solving the Problems” and the items in the embodiment is as follows. In the following, “the CPU 62 that executes a predetermined process according to a program stored in the memory 64” will be referred to as “a CPU 62 that executes a predetermined process” to simplify the description. The injection period acquisition processing unit corresponds to the CPU 62 that executes the processing of step S10, and the ignition processing unit for autonomous start corresponds to the CPU 62 that executes the processing of steps S14 to S20.

<Other Embodiments>
In addition, you may change at least one of each matter of the said embodiment as follows.
In the above embodiment, although the engine including only the internal combustion engine 10 is illustrated as a prime mover for applying power to the drive wheels, the invention is not limited thereto. For example, both a rotating electric machine and an internal combustion engine 10, such as a parallel hybrid vehicle or a series / parallel hybrid vehicle, may be provided as a prime mover for applying power to drive wheels. In this case, in the normal starting process, the initial rotation can be provided by the rotating electrical machine instead of the starter.

  The control device is not limited to one in which the CPU 62 executes all of the processing shown in FIG. 4 and the processing shown in FIG. 1 in accordance with a program stored in the memory 64. For example, the control device may be equipped with a dedicated hardware (application specific integrated circuit: ASIC) in addition to the CPU 62, and the processing of the injection processing unit M10 may be processed by the ASIC.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 12 ... Intake passage, 14 ... Intake valve, 18 ... Piston, 20 ... Combustion chamber, 22 ... Ignition device, 24 ... Fuel injection valve, 26 ... Fuel pump, 28 ... Crankshaft, 30 ... Starter, 32 ..... Exhaust valve, 34 ... Exhaust passage, 40 ... Ignition coil, 40 a ... Primary coil, 40 b ... Secondary coil, 42 ... Switching element, 44 ... Diode, 46 ... Resistance, 48 ... Spark plug, 50 ... Timing rotor , 52: tooth portion, 54: chipped portion, 60: control device, 62: CPU, 64: memory, 70: fuel pressure sensor, 72: accelerator sensor, 74: crank angle sensor.

Claims (1)

It is connected to the secondary coil by stopping the energization of the primary coil after the fuel injection valve that injects fuel into the combustion chamber of the internal combustion engine and the primary coil with the internal combustion engine controlled. In a control device of an internal combustion engine that operates an ignition device that discharges to a defective ignition plug,
An injection processing unit that operates the fuel injection valve to inject the fuel into the combustion chamber;
A fuel cut ignition processing unit for operating the ignition device to discharge the spark plug when the fuel cut processing is performed to stop the injection of the fuel when the crankshaft of the internal combustion engine is rotating;
When the injection processing unit resumes the control for injecting the fuel due to the request to restart the injection of the fuel by the injection processing unit when the fuel cut processing is performed, the fuel from the injection processing unit An injection period acquisition processing unit that acquires injection period information of
When the injection processing unit resumes the control for injecting the fuel, the injection period information is used based on the injection period information regardless of whether the fuel cut ignition processing unit performs the energization process of the primary coil. Until the timing when the end timing of the injection of the fuel by the injection processing unit or the timing elapsed from the restart time of the control of injecting the fuel by the necessary minimum value of the energization time of the primary side coil becomes the later timing. A control device for an internal combustion engine, comprising: an ignition processing unit for autonomous starting that energizes a next coil and stops energization of the primary coil at any one of the later timings.

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