JP2016003570A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an internal combustion engine capable of removing deposits of fuel injection valves by a simple control.SOLUTION: An internal combustion engine comprises: fuel injection valves injecting and supplying a fuel; a deposit determination unit determining whether a deposit adheres to an injection nozzle of each fuel injection valve; and an injection control unit executing a deposit removal fuel injection control to reduce the number of times of fuel injection from each fuel injection valve for a predetermined period and to increase a fuel injection quantity of the fuel injection valve per injection as compared with a case in which it is determined that no deposit adheres to each fuel injection valve if it is determined that the deposit adheres to each fuel injection valve.

Description

  The present invention relates to an internal combustion engine.

  Patent Document 1 discloses a cylinder fuel injection valve by decreasing the ratio of fuel injected from the port fuel injection valve to the intake port and increasing the ratio of fuel injected from the cylinder fuel injection valve to the combustion chamber. An internal combustion engine capable of removing deposits deposited on the inside is disclosed.

JP 2010-24927 A

  In the internal combustion engine described above, since the port fuel injection valve and the in-cylinder fuel injection valve are cooperatively controlled to remove deposits in the in-cylinder fuel injection valve, it is necessary to control at least two types of fuel injection valves simultaneously. Thus, in the structure which controls two types of fuel injection valves simultaneously, there exists a problem that the control for removing a deposit becomes complicated.

  The objective of this invention is providing the internal combustion engine which can remove the deposit of a fuel injection valve by simple control.

  An internal combustion engine according to an aspect of the present invention includes a fuel injection valve that injects and supplies fuel, and a deposit determination unit that determines whether or not deposit is attached to an injection port of the fuel injection valve. Further, when the internal combustion engine determines that the deposit is attached to the fuel injection valve, the internal combustion engine determines the number of times of fuel injection of the fuel injection valve in the predetermined period as compared to the case where it is determined that the deposit does not adhere. And an injection control unit that executes deposit removal fuel injection control so as to reduce and increase the fuel injection amount of one time of the fuel injection valve.

  According to the internal combustion engine of the present invention, by reducing the number of fuel injections in a predetermined period and increasing the fuel injection amount in one fuel injection, the fuel around the injection port is washed away by the fuel injected from the fuel injection valve. Can be removed. Therefore, deposit removal of the fuel injection valve can be realized by simple control of controlling one type of fuel injection valve.

FIG. 1 is a schematic configuration diagram of an internal combustion engine according to an embodiment of the present invention. FIG. 2 is a flowchart showing fuel reforming control executed by a controller provided in the internal combustion engine. FIG. 3A is a diagram illustrating the operation of the reforming fuel injection valve during normal reforming control execution. FIG. 3B is a diagram showing an operation of the reforming fuel injection valve during the first deposit removal control. FIG. 3C is a diagram illustrating an operation of the reforming fuel injection valve during the second deposit removal control. FIG. 4 is a flowchart showing the fuel state control executed by the controller. FIG. 5 is a diagram illustrating the EGR rate reduction control in the fuel state control.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an internal combustion engine (hereinafter simply referred to as “engine”) 1 according to an embodiment of the present invention.

  The engine 1 is a four-cylinder internal combustion engine, and is a direct injection internal combustion engine in which fuel is injected into a cylinder from a cylinder fuel injection valve 2 provided for each cylinder. Each cylinder of the engine 1 is provided with a spark plug that ignites the injected fuel.

  The engine 1 includes an intake passage 3 that guides fresh air (intake air) taken from the outside to the engine 1 and an exhaust passage 4 through which exhaust gas discharged from the combustion chamber of each cylinder of the engine 1 flows. .

  The exhaust passage 4 is provided with a three-way catalyst 5 for purifying exhaust gas. Exhaust gas discharged from each combustion chamber of the engine 1 in the exhaust stroke flows through the exhaust passage 4 and is purified by the three-way catalyst 5 and then released to the atmosphere. However, a part of the exhaust is returned to the intake passage 3 through the EGR passage 10 branched from the exhaust passage 4.

  The EGR passage 10 is a passage connecting the exhaust passage 4 and the intake passage 3. The EGR passage 10 branches from the exhaust passage 4 upstream of the three-way catalyst 5 and merges with the intake passage 3. The EGR passage 10 includes a reforming fuel injection valve 21, a fuel reforming catalyst 22, a hydrogen detection sensor (reformed fuel detection sensor) 23, an EGR cooler 11, and an EGR valve 12 in order from the exhaust passage 4 side (upstream side). Is provided.

  The EGR cooler 11 is a cooling device that cools gas (EGR gas) that passes through the EGR passage 10 and is returned to the intake passage 3 side.

  The EGR valve 12 is a valve that adjusts the flow rate of the EGR gas recirculated to the intake passage 3 side. The opening degree of the EGR valve 12 is controlled by the controller 40 so that the target EGR rate corresponding to the operating state is obtained. The EGR rate is a value obtained by dividing the recirculated exhaust gas amount by the intake air amount, and is defined as a ratio of exhaust gas in the intake air.

  The reforming fuel injection valve 21 is provided in the EGR passage 10 upstream of the fuel reforming catalyst 22. The reforming fuel injection valve 21 adds fuel to the exhaust before flowing into the fuel reforming catalyst 22 by injecting fuel composed of hydrocarbons into the EGR passage 10 upstream of the fuel reforming catalyst 22. To do.

  The reforming fuel injection valve 21 is connected to the fuel tank 30 through the supply passage 31. Gasoline as fuel is stored in the fuel tank 30, and the fuel in the fuel tank 30 is sent to the reforming fuel injection valve 21 by a fuel pump 32 provided in the supply passage 31. The reforming fuel injection valve 21 is configured to supply the same fuel as the fuel supplied to the engine 1 via the in-cylinder fuel injection valve 2 to the fuel reforming catalyst 22.

  The reforming fuel injection valve 21 is configured to inject gasoline, but may be configured to inject hydrocarbon fuel other than gasoline. As the fuel supplied to the fuel reforming catalyst 22, a hydrocarbon fuel such as light oil or methanol is used in addition to gasoline. In this embodiment, the fuel supplied to the reforming fuel injection valve 21 and the fuel supplied to the in-cylinder fuel injection valve 2 are the same fuel, but these fuels may be different fuels.

  The fuel reforming catalyst 22 is a catalyst that reforms the fuel (hydrocarbon fuel) supplied from the reforming fuel injection valve 21 to generate hydrogen as reformed fuel. As the fuel reforming catalyst 22, for example, a Rh / ZrO2 catalyst or a Rh / CeO2 catalyst is used. The reformed fuel is a fuel having higher combustibility than the fuel before reforming. The reformed fuel is supplied to the engine 1 at the time of executing EGR control, for example, when the engine is in an engine operating state where it is necessary to further improve the combustion stability.

  The hydrogen detection sensor 23 is provided in the EGR passage 10 between the fuel reforming catalyst 22 and the EGR cooler 11 or between the EGR cooler 11 and the EGR valve 12. The hydrogen detection sensor 23 detects the concentration of hydrogen contained in the gas passing through the EGR passage 10. A detection signal of the hydrogen detection sensor 23 is output to the controller 40.

  The controller 40 includes a microcomputer that includes a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller 40 may be configured by a plurality of microcomputers.

  In addition to the hydrogen detection sensor 23, the controller 40 receives signals from a crank angle sensor 41 that generates a crank angle signal at every predetermined crank angle and an accelerator pedal sensor 42 that detects the amount of depression of an accelerator pedal provided in the vehicle. The The crank angle signal is used as a signal representative of the engine rotation speed of the engine 1. The amount of depression of the accelerator pedal is used as a signal representative of the load of the engine 1.

  Based on these input signals, the controller 40 determines the injection timing and fuel injection amount of the in-cylinder fuel injection valve 2, the ignition timing of the spark plug, the injection timing and fuel injection amount of the reforming fuel injection valve 21, and the fuel pump 32. , And the opening degree of the EGR valve 12 are controlled.

  The three-way catalyst 5 efficiently purifies harmful components in the exhaust when the air-fuel ratio of the exhaust fluctuates in the vicinity of the stoichiometric air-fuel ratio, so the controller 40 allows the in-cylinder fuel injection valve 2 to obtain a stoichiometric air-fuel mixture. The fuel injection pulse width is determined.

  In addition, the controller 40 performs fuel reforming control for reforming the fuel injected from the reforming fuel injection valve 21 into reformed fuel by the fuel reforming catalyst 22 when executing EGR control for returning the exhaust gas to the intake passage 3 side. Execute.

  By the way, when the fuel reforming control is repeatedly executed, deposits are accumulated around the injection port of the reforming fuel injection valve 21. The deposit is a solidified part of the injected fuel or the like. When the deposit accumulates around the injection port in this way, the fuel injection amount injected from the reforming fuel injection valve 21 becomes smaller than the target injection amount, and as a result, the stoichiometric air-fuel ratio required by the engine 1 is established. I can't do that.

  Therefore, when a deposit is attached around the injection port of the reforming fuel injection valve 21, the controller 40 according to the present embodiment performs fuel injection control for removing the deposit during the fuel reforming control.

  The fuel reforming control executed by the controller 40 will be described with reference to FIG. The fuel reforming control is executed at a predetermined timing after the ignition switch is turned on.

  In step 101 (S101), the controller 40 determines whether or not a fuel reforming control execution condition is satisfied. The fuel reforming control execution condition is determined based on whether or not the engine operating state determined from the engine speed and the load is in a state of executing EGR control, for example.

  When the engine operating state is a state for executing the EGR control, the controller 40 determines that the fuel reforming control execution condition is satisfied, and executes the process of S102. In other cases, the controller 40 ends the fuel reforming control.

  In S <b> 102, the controller 40 determines whether deposits are attached (deposited) around the injection port of the reforming fuel injection valve 21.

  The controller 40 stores the hydrogen concentration detected by the hydrogen detection sensor 23 during the previous execution of the normal reforming control, reads the hydrogen concentration during the processing of S102, and performs deposit adhesion determination based on the read hydrogen concentration. The controller 40 determines that there is deposit adhesion when the hydrogen concentration is equal to or lower than the reference concentration, and determines that there is no deposit adhesion when the hydrogen concentration is higher than the reference concentration.

  In S102, the controller 40 executes the deposit adhesion determination based on the hydrogen concentration during the previous execution of the normal reforming control, but is not limited to this. For example, even if the deposit adhesion determination is executed by supplying fuel from the reforming fuel injection valve 21 to the fuel reforming catalyst 22 for a certain period of time after the processing of S101 and detecting the hydrogen concentration at that time by the hydrogen detection sensor 23. Good.

  If it is determined in S102 that there is no deposit adhesion, the controller 40 executes the processes of S103 and S104. On the other hand, if it is determined in S102 that there is deposit adhesion, the controller 40 executes the process of S105.

  In S103 and S104, the controller 40 executes normal reforming control until a predetermined time elapses. In normal reforming control, fuel is injected into the EGR passage 10 from the reforming fuel injection valve 21. The fuel reforming catalyst 22 generates reformed fuel (hydrogen) using the injected fuel. By supplying the reformed fuel with high combustibility generated in this way to the engine 1, even when a large amount of EGR gas is supplied to the engine 1, deterioration of combustibility in the engine 1 can be suppressed. It becomes possible.

  As shown in FIG. 3A, in the normal reforming control, the reforming fuel injection valve 21 is controlled to inject fuel four times within a predetermined period in which one piston moves from 0 ° to 720 ° in crank angle. The Four fuel injections at a crank angle of 0 ° to 720 ° are defined as one cycle, and this cycle is repeatedly executed for a predetermined time.

  The reforming fuel injection valve 21 injects fuel once at a timing when each of the four cylinders enters the intake stroke, and these four fuel injections are executed at equal intervals. In one fuel injection in the normal reforming control, the fuel injection pressure is set to the reference pressure Pt, and the fuel injection time (pulse width) is set to the reference time Tt. The fuel injection pressure corresponds to the fuel injection amount per unit time.

  When it is determined in S104 in FIG. 2 that a predetermined time has elapsed since the execution of the normal reforming control, the controller 40 ends the current fuel reforming control.

  By the way, when it is determined in S102 that deposits are attached to the reforming fuel injection valve 21, the controller 40 determines whether or not the first deposit removal control has been executed in S105.

  If the first deposit removal control has not been executed, the controller 40 executes the processes of S106 and S107. On the other hand, when the first deposit removal control has been executed, the controller 40 executes the processes of S108 and S109.

  In S106 and S107, the controller 40 executes the first deposit removal control until a predetermined time elapses. In the first deposit removal control, fuel is injected from the reforming fuel injection valve 21 in the manner shown in FIG. 3B.

  In the first deposit removal control, the reforming fuel injection valve 21 is controlled to inject fuel twice within a predetermined period in which one piston moves from 0 ° to 720 ° in crank angle. Two fuel injections at a crank angle of 0 ° to 720 ° are defined as one cycle, and this cycle is repeatedly executed for a predetermined time.

  The reforming fuel injection valve 21 injects the fuel once at a predetermined timing, and these two fuel injections are executed at equal intervals. In one fuel injection in the first deposit removal control, the fuel injection pressure is set to the reference pressure Pt, and the fuel injection time (pulse width) is set to a time T1 longer than the reference time Tt.

  As described above, in the first deposit removal control, the number of fuel injections in one cycle (predetermined period) is changed from 4 times to 2 times as compared with the normal reforming control time (when it is determined that no deposit is attached). The fuel injection amount in one fuel injection is increased. By increasing the fuel injection amount in one fuel injection, the deposit around the injection port is washed away and removed by the fuel injected from the reforming fuel injection valve 21.

  Further, even if the number of fuel injections in one cycle is reduced, the amount of fuel injection per time is increased, so that a decrease in the amount of fuel supplied to the fuel reforming catalyst 22 can be suppressed. For this reason, it is possible to maintain the theoretical air-fuel ratio even during the first deposit removal control.

  In the first deposit removal control, the fuel injection amount in one fuel injection is increased by setting the fuel injection pressure to the reference pressure Pt and the fuel injection time to the time T1. However, the fuel injection amount in one fuel injection may be increased by setting the fuel injection pressure to a pressure P1 (see FIG. 3B) higher than the reference pressure Pt and setting the fuel injection time to time T1. . In this way, when the fuel injection pressure is set to a pressure P1 higher than that during the normal reforming control, the fuel injection time may be set to the reference time Tt. The fuel injection pressure of the fuel injected from the reforming fuel injection valve 21 is adjusted by controlling the rotational speed of the fuel pump 32.

  When it is determined in S107 of FIG. 2 that a predetermined time has elapsed since the execution of the first deposit reforming control, the controller 40 ends the current fuel reforming control.

  On the other hand, when it is determined in S105 that the first deposit removal control has been executed, the controller 40 executes the processes of S108 and S109. In S108 and S109, the controller 40 executes the second deposit removal control until a predetermined time elapses.

  In the second deposit removal control, fuel is injected from the reforming fuel injection valve 21 in the manner shown in FIG. 3C. If it is determined in S109 that a predetermined time has elapsed since the execution of the second deposit removal control, the controller 40 ends the current fuel reforming control.

  In the second deposit removal control, the reforming fuel injection valve 21 is controlled to inject fuel once within a predetermined period in which one piston moves from 0 ° to 720 ° in crank angle. One fuel injection at a crank angle of 0 ° to 720 ° is defined as one cycle, and this cycle is repeatedly executed for a predetermined time.

  The reforming fuel injection valve 21 injects fuel once at a predetermined timing. In one fuel injection in the second deposit removal control, the fuel injection pressure is set to the reference pressure Pt, and the fuel injection time (pulse width) is longer than the fuel injection time T1 in the first deposit removal control. Set to

  As described above, in the second deposit removal control, the number of fuel injections in one cycle (predetermined period) is reduced from two to one in comparison with that in the first deposit removal control, and further fuel injection in one fuel injection. The amount is increased. By increasing the injection amount in one fuel injection as compared with the first deposit removal control, the deposit around the injection port of the reforming fuel injection valve 21 can be easily removed. In addition, even if the number of fuel injections in one cycle is reduced, the fuel injection amount per time is increased, so that the stoichiometric air-fuel ratio can be maintained.

  In the second deposit removal control, the fuel injection amount in one fuel injection is increased by setting the fuel injection pressure to the reference pressure Pt and the fuel injection time to time T2. However, the fuel injection pressure is set to the pressure P2 (see FIG. 3C) higher than the fuel injection pressure P1 at the time of the first deposit removal control, and the fuel injection time is set to the time T1, whereby the fuel in one fuel injection is set. The injection amount may be increased. As described above, when the fuel injection pressure is set to the pressure P2 higher than that at the time of the first deposit control, the fuel injection time may be set to the reference time Tt or the fuel injection time T1 at the time of the first deposit control.

  During the second deposit removal control, the driver or the like may be informed that deposits are attached to the reforming fuel injection valve 21 and that there is a possibility that the fuel reforming system may be abnormal. In this case, the abnormality is notified by turning on or blinking a warning lamp in the cab or outputting a warning sound in the cab.

  Next, the combustion state control executed by the controller 40 will be described with reference to FIG. The combustion state control is control executed during deposit removal control in order to maintain combustion stability in the engine 1. The combustion state control is repeatedly executed at a predetermined control cycle.

  In S201, the controller 40 determines whether or not deposit removal control is being executed. The deposit removal control includes the first deposit removal control in S106 in FIG. 2 and the second deposit removal control in S108 in FIG.

  When the first deposit removal control or the second deposit removal control is being executed, the controller 40 executes the process of S202. On the other hand, when the first deposit removal control or the second deposit removal control is not executed, the controller 40 ends the combustion state control.

  In S202, the controller 40 executes EGR rate lowering control. At the time of deposit removal control, as shown in FIGS. 3B and 3C, the number of injections of the reforming fuel injection valve 21 within one cycle (predetermined period) is reduced compared to that during normal reforming control. In such a case, there is a possibility that a small amount of difference between cylinders is generated in the amount of fuel supplied to each cylinder, and the combustibility in the engine 1 may be deteriorated. When the combustibility is deteriorated, vibration is generated in the engine 1 or misfire occurs. Therefore, in order to maintain combustion stability during deposit removal control, the controller 40 decreases the EGR rate according to the number of injections of the reforming fuel injection valve 21 in one cycle.

  FIG. 5 is a graph showing the relationship between the EGR rate and the combustion stability in the engine 1. A line L1 indicates the relationship between the EGR rate and the combustion stability during normal reforming control. A line L2 indicates a relationship between the EGR rate and the combustion stability during the first deposit removal control, and a line L3 indicates a relationship between the EGR rate and the combustion stability during the second deposit removal control.

  As shown by the line L1 in FIG. 5, the EGR rate is set to a relatively large value R1 within a range where the combustion stability does not exceed the combustion stability limit in order to improve the exhaust performance and the fuel consumption performance during the normal reforming control. .

  However, if the number of injections of the reforming fuel injection valve 21 per cycle is reduced to two by the first deposit removal control, a small amount of cylinder-to-cylinder difference occurs in the amount of fuel supplied to each cylinder, The combustibility in the engine 1 may be deteriorated. As a result, the line indicating the combustion stability during the first deposit removal control is a line as indicated by a line L2 in FIG. Therefore, if the EGR rate during the first deposit removal control is set to the same value R1 as the EGR rate during the normal reforming control, the combustibility in the engine 1 is deteriorated. Therefore, during the first deposit removal control, the EGR rate is set to a value R2 that is smaller than the value R1 during normal reforming control.

  Since the line indicating the combustion stability is a line as indicated by line L3 in FIG. 5 when the second deposit removal control is executed, the EGR rate at the time of the second deposit removal control is based on the value R2 at the time of the first deposit removal control. Is also set to a small value R3.

  At the time of deposit removal control, the EGR rate is set to be smaller as the number of injections of the reforming fuel injection valve 21 in one cycle (predetermined period) is reduced as described above, so that combustion stability in the engine 1 is maintained. Is possible.

  Returning to FIG. 4, the processing after S203 in the combustion state control will be described.

  After the process of S202, the controller 40 executes the process of S203. In S203, the controller 40 executes ignition timing MBT control. In the ignition timing MBT control, the advance angle correction or the delay angle correction is performed so that the ignition timing set according to the engine operating state approaches the optimum ignition timing (MBT). The ignition timing at the time of the second deposit removal control is set to a timing closer to the MBT than the ignition timing at the time of the first deposit removal control.

  By executing the ignition timing MBT control in this way, it is possible to maintain the combustion stability in the engine 1 during the deposit removal control.

  When the ignition timing at the time of deposit removal control is already set to MBT, the controller 40 executes the process of S204 without performing the ignition timing MBT control. After the process of S204, the controller 40 ends the combustion state control.

  In S204, the controller 40 executes in-cylinder flow occurrence control. In the in-cylinder flow generation control, a gas flow such as a tumble flow or a swirl flow is generated in the combustion chamber of the engine 1. For example, during the intake process, a tumble flow is generated by closing the upper or lower portion of the passage with a tumble generating valve provided in the intake passage. A swirl flow is generated by closing one of the two intake valves provided for one cylinder during the intake process.

  By executing the in-cylinder flow occurrence control in this way, it is possible to maintain the combustion stability in the engine 1 during the deposit removal control.

  The controller 40 is configured to execute the three processes of S202 to S204 at the time of deposit control execution, but is configured to execute any one or two of the controls in S202 to S204. Also good.

  According to the engine 1 of the present embodiment described above, the following effects can be obtained.

  The engine 1 has a controller 40, and the controller 40 determines whether or not deposit is attached to the injection port of the reforming fuel injection valve 21. Then, when it is determined that the deposit is attached, the controller 40 reduces the number of fuel injections in one cycle (predetermined period) as compared with the time of normal reforming control, and the amount of fuel injection per time The first deposit removal control is executed so that is increased. Thus, by reducing the number of fuel injections in one cycle (predetermined period) and increasing the injection amount in one fuel injection, the fuel injected from the reforming fuel injection valve 21 deposits around the injection port. It can be washed away. Therefore, deposit removal of the reforming fuel injection valve 21 can be realized by simple control of controlling one type of fuel injection valve.

  Further, when the deposit is attached to the injection port of the reforming fuel injection valve 21 after the first deposit removal control, the controller 40 performs fuel in one cycle (predetermined period) as compared with the previous first deposit removal control. The second deposit removal control is executed so that the number of injections is reduced and the fuel injection amount for one injection is increased. By executing the second deposit removal control in this way, it becomes possible to more reliably remove the deposit around the injection port of the reforming fuel injection valve 21.

  Further, the controller 40 executes any one of the EGR rate reduction control, the ignition timing MBT control, and the in-cylinder flow occurrence control when the deposit removal control is executed and the number of fuel injections of the reforming fuel injection valve 21 is reduced. Perform combined control or all control. Therefore, even when the number of fuel injections of the reforming fuel injection valve 21 is reduced by the deposit removal control and the amount of reformed fuel generated by the fuel reforming catalyst 22 is reduced, the combustion stability in the engine 1 is maintained. Is possible.

  Further, the controller 40 determines whether or not deposit is attached to the injection port of the reforming fuel injection valve 21 based on the detection value of the hydrogen detection sensor 23. As described above, since the hydrogen as the reformed fuel produced by the fuel reforming catalyst 22 is directly detected by the hydrogen detection sensor 23, it is possible to enhance the determination system for deposit adhesion determination.

  It should be noted that the present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  In the engine 1 according to the present embodiment described above, the number of fuel injections of the reforming fuel injection valve 21 during normal reforming control is set to 4 times per cycle. However, the number of fuel injections is not limited to four, and is set to an arbitrary number as necessary. Similarly, the number of fuel injections per cycle during the first deposit removal control and the second deposit removal control is also set to an arbitrary number as necessary. However, the number of fuel injections per cycle during the first deposit removal control is set to be smaller than that during the normal reforming control, and the number of fuel injections per cycle during the second deposit removal control is greater than that during the first deposit removal control. Is set to less.

  The controller 40 is configured to perform deposit adhesion determination based on the detection value of the hydrogen detection sensor 23, but is not limited to such a configuration. For example, an air-fuel ratio sensor that detects the air-fuel ratio is disposed in the EGR passage 10 downstream of the fuel reforming catalyst 22, and the controller 40 deposits deposits on the reforming fuel injection valve 21 based on the detected value of the air-fuel ratio sensor. You may be comprised so that determination may be performed. In the case of such a configuration, the deposit adhesion determination can be performed by comparing the air-fuel ratio in the EGR passage 10 detected by the air-fuel ratio sensor with a preset reference air-fuel ratio.

  In addition, when the controller 40 determines that the deposit is attached after the second deposit removal control is executed, the controller 40 stops the fuel injection by the reforming fuel injection valve 21 or informs the driver that an abnormality has occurred in the fuel reforming system. You may be comprised so that it may alert | report.

  In this embodiment, the case where the deposit of the reforming fuel injection valve 21 in the fuel reforming system that supplies the reformed fuel to the engine 1 is removed has been described. However, the technical idea of the present invention can also be applied to the in-cylinder fuel injection valve 2 and the port fuel injection valve that injects fuel into the intake port. The controller 40 determines whether or not deposits are attached to the injection port of the fuel injection valve. When deposits are present, the number of fuel injections in a predetermined period is reduced compared to the case where no deposits are attached. Increase the fuel injection amount. As a result, the deposit around the injection port can be washed away by the fuel injected from the fuel injection valve. Therefore, deposit removal of the fuel injection valve can be realized by simple control of controlling one type of fuel injection valve.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 3 Intake passage 4 Exhaust passage 10 EGR passage 11 EGR cooler 12 EGR valve 21 Fuel reforming valve 22 Fuel reforming catalyst 23 Hydrogen detection sensor 30 Fuel tank 32 Fuel pump 40 Controller

Claims (8)

A fuel injection valve for supplying fuel;
A deposit determination unit for determining whether or not deposit is attached to the injection port of the fuel injection valve;
When it is determined that deposit is attached to the fuel injection valve, the number of times of fuel injection of the fuel injection valve in a predetermined period is reduced compared to a case where it is determined that no deposit is attached, An injection control unit that executes deposit removal fuel injection control so as to increase the fuel injection amount of one time of the fuel injection valve;
An internal combustion engine. The internal combustion engine according to claim 1,
The injection control unit increases the fuel injection pressure of the fuel injection valve when it is determined that no deposit is attached to the fuel injection valve, compared with a case where it is determined that no deposit is attached. Let
Internal combustion engine. The internal combustion engine according to claim 1 or 2,
When it is determined that deposits are attached to the fuel injection valve after execution of deposit removal fuel injection control, the injection control unit sets the number of fuel injections in a predetermined period compared to the previous deposit removal fuel injection control. Reduce and increase the amount of fuel injection per time,
Internal combustion engine. An internal combustion engine according to any one of claims 1 to 3,
The injection control unit, when it is determined that deposit is attached to the fuel injection valve after execution of deposit removal fuel injection control, to increase the fuel injection pressure than during the previous deposit removal fuel injection control,
Internal combustion engine. An internal combustion engine according to any one of claims 1 to 4,
A combustion state control unit for controlling the combustion state of the fuel in the combustion chamber;
The combustion state control unit ignites toward an optimal ignition timing (MBT) that reduces an EGR rate defined as a ratio of exhaust gas contained in intake air when the number of fuel injections is reduced by the injection control unit. Execute any combination of advancement or retardation of the timing and generation of gas flow in the combustion chamber, or all control.
Internal combustion engine. An internal combustion engine according to any one of claims 1 to 5,
An EGR passage connecting the exhaust passage and the intake passage;
A fuel reforming catalyst provided in the EGR passage,
The fuel injection valve is disposed in the EGR passage so as to supply fuel to the fuel reforming catalyst;
Internal combustion engine. The internal combustion engine according to claim 6,
A reformed fuel detection sensor that is provided in the EGR passage downstream of the fuel reforming catalyst and detects the concentration of the reformed fuel generated by the fuel reforming catalyst;
The deposit determination unit determines whether or not deposit is attached to the fuel injection valve based on a detection value of the reformed fuel detection sensor;
Internal combustion engine. The internal combustion engine according to claim 6,
An air-fuel ratio sensor provided in the EGR passage downstream of the fuel reforming catalyst and detecting an air-fuel ratio of gas passing through the EGR passage;
The deposit determination unit determines whether or not deposit is attached to the fuel injection valve based on a detection value of the air-fuel ratio sensor;
Internal combustion engine.

Images