JP2005299525A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve engine performance by supplying hydrogen by an appropriate method according to an operating condition. <P>SOLUTION: In this control device for an internal combustion engine, a gasoline injection valve 26 ejecting gasoline and a hydrogen fuel port injection valve 28 ejecting hydrogen are installed in an intake port 18. A hydrogen fuel cylinder injection valve 30 ejecting hydrogen into a cylinder is installed in a cylinder head 14. The injection valve to be used is selected according to the operating condition of the internal combustion engine 10. During normal operation, the gasoline injection valve 26 and hydrogen fuel port injection valve 28 are selected. During high load, the gasoline injection valve 26 and hydrogen fuel cylinder injection valve 30 are selected. At starting, only the hydrogen fuel cylinder injection valve 30 is selected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly to a control device for an internal combustion engine that uses both main fuel such as gasoline and hydrogen fuel as fuel.

  Conventionally, for example, Japanese Patent Application Laid-Open No. 9-195857 discloses an internal combustion engine that includes a gasoline injection valve that injects gasoline into an intake port and a hydrogen port injection valve that injects hydrogen into an intake port. Conventionally, for example, Japanese Patent Application Laid-Open No. 7-63128 discloses an internal combustion engine including a gasoline injection valve that injects gasoline into an intake port and a hydrogen in-cylinder injection valve that injects hydrogen into the cylinder. When hydrogen is used as a fuel, the combustion speed is much faster than in the case of gasoline. For this reason, in any of the above conventional techniques, the combustion state can be improved by adding hydrogen while using gasoline as the main fuel.

JP-A-9-195857 JP-A-7-63128

  In the internal combustion engine using gasoline as the main fuel as in the above-described conventional technology, if hydrogen is used as the fuel, various merits can be obtained according to the operating state of the internal combustion engine. However, in the configuration in which the fuel injection valve for supplying hydrogen is provided in either the intake port or the cylinder as in the conventional technique described above, the advantage of using hydrogen alone as the fuel together with the main fuel cannot be utilized. .

  The present invention has been made to solve the above-described problems, and can supply hydrogen by an appropriate technique according to the operating state, thereby improving the engine performance. An object is to provide a control device.

In order to achieve the above object, a first invention is a main fuel injection valve that injects main fuel;
A hydrogen fuel port injection valve for injecting hydrogen fuel into the intake port;
A hydrogen fuel in-cylinder injection valve for injecting hydrogen fuel into the cylinder;
An injection valve selection means for selecting an injection valve to be used for fuel injection from the main fuel injection valve, the hydrogen fuel port injection valve, and the hydrogen fuel in-cylinder injection valve according to the operating state of the internal combustion engine;
Fuel injection execution means for executing fuel injection using the injection valve selected by the injection valve selection means.

In a second aspect based on the first aspect, the injection valve selection means selects fuel injection only by the hydrogen fuel in-cylinder injection valve when starting the internal combustion engine,
The fuel injection execution means executes fuel injection so as to realize a stratified operation.

In a third aspect based on the first aspect, the main fuel injection valve is an injection valve that injects main fuel into the intake port,
The injection valve selection means selects fuel injection by the main fuel injection valve and the hydrogen fuel port injection valve during normal operation of the internal combustion engine.

  According to a fourth aspect of the present invention based on the third aspect, the injection valve selection means is arranged such that the main fuel injection valve and the hydrogen are in a range from when acceleration is started until a predetermined injection valve change period has elapsed. The fuel injection by the fuel cylinder injection valve is selected.

In a fifth aspect based on the first aspect, the injection valve selection means selects fuel injection by the main fuel injection valve and the hydrogen fuel in-cylinder injection valve when the internal combustion engine is at a high load,
The fuel injection execution means starts fuel injection from the hydrogen fuel in-cylinder injection valve after the intake valve is closed.

In a sixth aspect based on the first aspect, the injection valve selection means selects fuel injection by the main fuel injection valve and the hydrogen fuel in-cylinder injection valve when knocking is detected. ,
The fuel injection execution means starts fuel injection from the hydrogen fuel in-cylinder injection valve after the intake valve is closed.

Further, according to a seventh aspect based on the first aspect, the injection valve selecting means uses the main fuel injection valve and the hydrogen fuel in-cylinder injection valve when the exhaust gas temperature exceeds a predetermined upper limit value. Select fuel injection,
The fuel injection execution means starts fuel injection from the hydrogen fuel in-cylinder injection valve after the intake valve is closed.

  According to the first invention, by selecting an injection valve used for fuel injection according to the operating state of the internal combustion engine, hydrogen can be supplied in an appropriate manner with respect to various operating states of the internal combustion engine. it can. For this reason, according to the present invention, the merit of using hydrogen as the fuel alone or with the main fuel can be maximized, and the performance of the internal combustion engine can be improved.

  According to the second invention, at the time of start-up, the hydrogen fuel in-cylinder injection valve is selected. When stratified operation is performed using hydrogen as a fuel, lean combustion operation can be performed with an air excess rate significantly higher than that of main fuel such as gasoline, and unburned HC is not discharged. Therefore, according to the present invention, the internal combustion engine can be operated with high efficiency by selecting the hydrogen fuel in-cylinder injection valve at the time of starting.

  According to the third invention, the main fuel injection valve and the hydrogen fuel port injection valve are selected during normal operation. At this time, if hydrogen is injected into the intake port instead of into the cylinder, the mixed state of hydrogen injected into the intake port and the main fuel and the mixed state of these and air can be improved. For this reason, according to the present invention, it is possible to extend the limit at which lean-burn operation can be further performed as compared with the case where hydrogen is directly injected into the cylinder, and as a result, further improvement of fuel consumption performance and exhaust gas can be achieved. Can be realized.

  According to the fourth invention, at the initial stage of acceleration, the main fuel injection valve and the hydrogen fuel in-cylinder injection valve are selected. The hydrogen fuel injection valve has a higher injection pressure than the hydrogen fuel port injection valve. For this reason, by selecting the hydrogen fuel in-cylinder injection valve at the time of acceleration, it is possible to increase the hydrogen injection amount with high followability as compared with the case of using the hydrogen fuel port injection valve. For this reason, according to the present invention, hydrogen can be supplied with a good response during acceleration.

  According to the fifth aspect of the invention, the main fuel injection valve and the hydrogen fuel in-cylinder injection valve are selected at the time of high load. At this time, since the hydrogen is supplied into the cylinder after the intake valve is closed, the intake air amount does not decrease. For this reason, according to the present invention, it is possible to improve the torque by obtaining the combustion improvement effect by hydrogenation at the time of high load.

  According to the sixth aspect, when knocking is detected, the main fuel injection valve and the hydrogen fuel in-cylinder injection valve are selected. Therefore, according to the present invention, since the intake air amount does not decrease when hydrogen is supplied, knocking can be eliminated without reducing the torque.

  According to the seventh aspect, when the exhaust temperature exceeds a predetermined upper limit value, the main fuel injection valve and the hydrogen fuel in-cylinder injection valve are selected. For this reason, according to the present invention, since the amount of intake air does not decrease when hydrogen is supplied, the exhaust temperature can be lowered without reducing the torque, and thus the catalyst can be protected. .

Embodiment 1 FIG.
FIG. 1 is a diagram for explaining a configuration of an internal combustion engine 10 according to a first embodiment of the present invention. A piston 12 that reciprocates inside the cylinder of the internal combustion engine 10 is provided. Further, the internal combustion engine 10 includes a cylinder head 14. A combustion chamber 16 is formed between the piston 12 and the cylinder head 14. An intake port 18 and an exhaust port 20 communicate with the combustion chamber 16. An intake valve 22 and an exhaust valve 24 are disposed in the intake port 18 and the exhaust port 20, respectively.

  The intake port 18 is provided with a gasoline injection valve 26 that injects gasoline into the port. The intake port 18 is provided with a hydrogen fuel port injection valve 28 for injecting hydrogen into the port. Further, a hydrogen fuel in-cylinder injection valve 30 for injecting hydrogen into the cylinder is disposed in the cylinder head 14.

  A gasoline tank 34 communicates with the gasoline injection valve 26 via a gasoline supply pipe 32. The gasoline supply pipe 32 includes a pump 36 between the gasoline injection valve 26 and the gasoline tank 34. The pump 36 can supply gasoline to the gasoline injection valve 26 at a predetermined pressure. For this reason, the gasoline injection valve 26 is able to inject an amount of gasoline into the intake port 18 according to the opening time by opening the valve in response to a drive signal supplied from the outside.

  The system of this embodiment includes a hydrogen tank 38 for storing hydrogen in a gaseous state at a high pressure. A hydrogen supply pipe 40 communicates with the hydrogen tank 38. The hydrogen supply pipe 40 is branched at a branch point 42 in the middle thereof, and then communicated with the hydrogen fuel port injection valve 28 and the hydrogen fuel in-cylinder injection valve 30, respectively. In the system of this embodiment, hydrogen gas charged into the hydrogen tank 38 from the outside is used as the hydrogen fuel supplied to the hydrogen fuel port injection valve 28 and the hydrogen fuel cylinder injection valve 30. The hydrogen fuel supplied to these injection valves is not limited to this, and a hydrogen-rich gas containing high-concentration hydrogen generated on the vehicle or supplied from the outside may be used.

  In the hydrogen supply pipe 40, a primary regulator 44 is disposed between the hydrogen tank 38 and the branch point 42, and a secondary regulator 46 is disposed between the branch point 42 and the hydrogen fuel port injection valve 28. Has been. According to such a configuration, hydrogen in the hydrogen tank 38 is supplied to the hydrogen fuel in-cylinder injection valve 30 at a predetermined pressure reduced by the primary regulator 44. Further, hydrogen is supplied to the hydrogen fuel port injection valve 28 at a predetermined pressure that is further reduced by the secondary regulator 46. For this reason, the hydrogen fuel in-cylinder injection valve 30 and the hydrogen fuel port injection valve 28 are opened in response to a drive signal supplied from the outside, so that an amount of hydrogen corresponding to the opening time of each cylinder Can be injected into the intake and intake ports 18.

  In the hydrogen supply pipe 40, a fuel pressure sensor 48 is disposed between the branch point 42 and the hydrogen fuel in-cylinder injection valve 30. The fuel pressure sensor 48 is a sensor that emits an output corresponding to the pressure of hydrogen supplied to the hydrogen fuel in-cylinder injection valve 30. The hydrogen fuel in-cylinder injection valve 30 is supplied with hydrogen having a pressure higher than that of the hydrogen fuel port injection valve 28. In the system of this embodiment, the primary regulator 44 is controlled based on the output generated by the fuel pressure sensor 48. For this reason, even when the pressure of the hydrogen supplied from the hydrogen tank 38 fluctuates, the hydrogen can be supplied to the hydrogen fuel in-cylinder injection valve 30 at a stable pressure.

  The system of this embodiment includes an ECU 50. In addition to the fuel pressure sensor 48 described above, the ECU 50 includes a KCS sensor that detects the occurrence of knocking in order to grasp the operating state of the internal combustion engine 10, a throttle opening, an engine speed, an exhaust temperature, a coolant temperature, a lubricating oil Various sensors (not shown) for detecting temperature, catalyst bed temperature and the like are connected. The ECU 50 is connected to actuators such as the gasoline injection valve 26, the hydrogen fuel port injection valve 28, the hydrogen fuel in-cylinder injection valve 30, and the pump 36 described above. According to such a configuration, the ECU 50 can arbitrarily select an injection valve that performs fuel injection according to the operating state of the internal combustion engine 10.

  Next, with reference to FIG. 2, an operation method in which the system of the present embodiment selects and executes an injection valve to be used according to the operation state of the internal combustion engine 10 will be described.

  FIG. 2 is a diagram for explaining an operation method of the internal combustion engine 10 executed in the first embodiment of the present invention. The system according to the present embodiment selects one of the hydrogen fuel port injection valve 28 and the hydrogen fuel in-cylinder injection valve 30 as an injection valve that supplies hydrogen together with gasoline as fuel according to the operating state of the internal combustion engine 10. It is characterized by that. As shown in FIG. 2, in a normal operation region that is mainly used, a gasoline injection valve 26 and a hydrogen fuel port injection valve 28 are selected as injection valves for executing fuel injection. More specifically, a lean combustion operation is performed using these injection valves.

  When hydrogen is used as a fuel, the combustion speed is much faster than in the case of gasoline. For this reason, in a normal operation area | region, a combustion state can be improved by supplying hydrogen with gasoline, and the limit of the excess air ratio which can implement | achieve a lean combustion operation stably can be raised significantly. Further, in this operation region, the hydrogen fuel port injection valve 28 is used together with the gasoline injection valve 26 and hydrogen is injected into the intake port 18 instead of into the cylinder, so that the hydrogen injected into the intake port 18 and gasoline It is possible to improve the mixing state and the mixing state between them and air. For this reason, according to the system of the present embodiment, it is possible to further extend the limit at which the lean combustion operation can be performed, as compared with the case where hydrogen is directly injected into the cylinder by the hydrogen fuel in-cylinder injection valve 30. As a result, it is possible to achieve further improvement in fuel efficiency and purification of exhaust gas.

  As shown in FIG. 2, in the high load region, the gasoline injection valve 26 and the hydrogen fuel in-cylinder injection valve 30 are selected as the injection valves for executing the fuel injection in order to give priority to the output. More specifically, in the high load region, fuel injection is performed by the gasoline injection valve 26 so as to achieve the output air-fuel ratio, and hydrogen is injected after the intake valve 22 is closed by the hydrogen fuel in-cylinder injection valve 30. It is supposed to be injected into the cylinder. According to such a configuration, the combustion state can be improved by hydrogenation, so that the torque can be improved.

  Further, by using the hydrogen fuel in-cylinder injection valve 30 instead of the hydrogen fuel port injection valve 28 in the high load region, hydrogen is supplied into the cylinder after the intake valve 22 is closed as described above. Can do. Since hydrogen is a gas fuel, if hydrogen is injected into the intake port 18 or into the cylinder before the intake valve 22 is closed, the amount of intake air is reduced by the amount of supplied hydrogen. On the contrary, the torque is reduced as compared with the case of fuel injection using only gasoline. On the other hand, according to the system of the present embodiment, the amount of intake air sucked into the cylinder is not reduced, so that it is possible to improve the torque by obtaining the combustion improvement effect by hydrogen addition. .

  Further, as shown in FIG. 2, at the time of start-up (including the time of start-up here and immediately after start-up and the time of cool-down until completion of warm-up), the hydrogen fuel cylinder is used as an injection valve for executing fuel injection. Only the injection valve 30 is selected. More specifically, at the time of start-up, the stratified operation is executed by the hydrogen fuel in-cylinder injection valve 30. This stratified operation is an operation in which fuel is injected during the compression stroke so that an air-fuel mixture layer having excellent ignitability is formed around the spark plug during ignition. If such a stratified operation is executed, when viewed as the whole fuel supplied into the cylinder, compared to a case where fuel is injected into the intake port 18 or uniformly into the cylinder, Combustion can be realized with a higher excess air ratio.

In the present embodiment, the stratified operation described above can be performed by using the hydrogen fuel in-cylinder injection valve 30 instead of the hydrogen fuel port injection valve 28. Since hydrogen has good ignitability, stratified operation using hydrogen as a fuel makes it possible to achieve lean combustion operation with a significantly higher excess air ratio than when gasoline is used as fuel. Therefore, further adding, unlike in the case of gasoline, there is no problem of NO _X emissions increases. In addition, at the time of start-up, only the minimum necessary torque is required for the internal combustion engine 10, so that combustion using only hydrogen is sufficient. Furthermore, according to the method of the present embodiment, there is no need to increase the amount of fuel to improve ignitability at the time of starting, as in the case of using gasoline as fuel, and unburned hydrocarbons (HC) are discharged. It never happens. For this reason, according to the system of the present embodiment, the internal combustion engine 10 can be operated with high efficiency by the stratified operation using hydrogen as fuel at the time of starting.

  FIG. 3 is a flowchart of a routine executed by the ECU 50 in order to realize the above functions in the first embodiment. In the routine shown in FIG. 3, first, the catalyst bed temperature, the engine coolant temperature, and the engine lubricating oil temperature are acquired (step 100). Next, it is determined whether all the temperatures obtained in step 100 are equal to or higher than a predetermined value (step 102). Specifically, it is determined whether or not the warm-up is finished after the internal combustion engine 10 is started.

If it is determined in step 102 that the warm-up has not ended, the stratification operation by the hydrogen fuel in-cylinder injection valve 30 is executed (step 104).
On the other hand, if it is determined in step 102 that the warm-up has been completed, the throttle opening is acquired (step 106). Next, based on the throttle opening degree, it is determined whether or not it is in a high load range (step 108).

As a result, when it is determined in step 108 that the vehicle is not in the high load region, that is, in the normal operation region, the lean combustion operation is performed by the gasoline injection valve 26 and the hydrogen fuel port injection valve 28 (step). 110).
On the other hand, if it is determined in step 108 that the engine is in the high load region, gasoline is injected by the gasoline injection valve 26 and the hydrogen fuel in-cylinder injection valve 30 to the output air-fuel ratio, and the cylinder An output-priority operation in which hydrogen is added is executed (step 112).

  According to the processing of the routine shown in FIG. 3 described above, hydrogen can be supplied by selecting an optimal injection valve in accordance with the operating state of the internal combustion engine 10, and as a result, in all operating regions, hydrogen is supplied. It is possible to perform driving that maximizes the benefits of using the. For this reason, according to the system of the present embodiment, each performance of the engine, such as improvement of fuel consumption performance, purification of exhaust gas, and improvement of output performance, can be improved in each operation state.

  In the first embodiment described above, the gasoline injection valve 26 corresponds to the “main fuel injection valve” in the first invention. Further, when the ECU 50 executes the processing of steps 102 and 108, the “injection valve selection means” in the first invention executes the processing of steps 104, 110, and 112. The “fuel injection execution means” in FIG.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIG.
The system of the present embodiment is realized by causing the ECU 50 to execute the routine shown in FIG. 4 using the apparatus configuration of the first embodiment described above.

  In Embodiment 1 described above, hydrogen is supplied together with gasoline in order to prioritize output in the high load region. In contrast, the system of the present embodiment is characterized in that hydrogen is not always added in a high load region, but hydrogen is added as necessary.

  More specifically, in the system of this embodiment, in the high load region, fuel injection is executed by the gasoline injection valve 26 so that the output air-fuel ratio becomes the same. When such an operation is performed, knocking may occur particularly in a low rotation range. Therefore, in the system of this embodiment, when knocking occurs, hydrogen is injected into the cylinder from the hydrogen fuel in-cylinder injection valve 30 in addition to gasoline injection. As mentioned above, the addition of hydrogen increases the combustion rate. For this reason, by adding hydrogen when knocking occurs, knocking can be eliminated without having to increase the amount of gasoline or retard the ignition timing. Further, by using the hydrogen fuel in-cylinder injection valve 30, hydrogen can be injected into the cylinder after the intake valve 22 is closed. Therefore, knocking can be eliminated without reducing the amount of fresh air sucked into the cylinder, that is, without reducing torque.

  Further, when the engine is operated at an output air-fuel ratio using gasoline as fuel in a high load region, the exhaust temperature becomes considerably higher than that during normal operation, particularly at a high speed. If the exhaust temperature becomes too high, there is a concern about the deterioration of the catalyst disposed in the exhaust passage. Therefore, in the system of the present embodiment, when the exhaust gas temperature exceeds a predetermined upper limit value, hydrogen is injected into the cylinder from the hydrogen fuel in-cylinder injection valve 30 in addition to gasoline injection. Combustion is completed faster as the combustion rate increases due to hydrogenation. As a result, more heat energy of the fuel is converted into work, so that the temperature of the exhaust gas when the exhaust valve 24 is opened decreases. For this reason, by adding hydrogen when the exhaust gas temperature exceeds the upper limit value, the exhaust gas temperature can be lowered. As a result, combustion can be improved and the catalyst can be protected. Also in this case, the hydrogen fuel in-cylinder injection valve 30 is used to inject hydrogen into the cylinder after the intake valve 22 is closed, thereby reducing the amount of fresh air drawn into the cylinder. That is, torque is not reduced.

  FIG. 4 is a flowchart of a routine executed by the ECU 50 shown in FIG. 1 in order to select a suitable injection valve according to the operating state of the internal combustion engine 10 and execute fuel injection in the second embodiment. In FIG. 4, the same steps as those shown in FIG. 3 in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.

In the routine shown in FIG. 4, when it is determined that the vehicle is in the high load region (step 108), the output of the KCS sensor is acquired (step 114), and knocking occurs based on the sensor information. It is determined whether or not (step 116).
As a result, when it is determined in step 116 that knocking has occurred, the gasoline injection valve 26 and the hydrogen fuel in-cylinder injection valve 30 are selected as injection valves (step 112).

  On the other hand, if it is determined in step 116 that knocking has not occurred, then the exhaust temperature is acquired (step 118), and it is determined whether or not the acquired exhaust temperature exceeds the upper limit value. (Step 120).

As a result, when it is determined in step 120 that the exhaust gas temperature exceeds the upper limit value, the gasoline injection valve 26 and the hydrogen fuel in-cylinder injection valve 30 are selected as injection valves (step 112).
On the other hand, if it is determined in step 120 that the exhaust gas temperature does not exceed the upper limit value, only the gasoline injection valve 26 is selected as the injection valve (step 122).

  According to the processing of the routine shown in FIG. 4 described above, in the high load region, when occurrence of knocking or exceeding the upper limit of the exhaust temperature is confirmed, by adding hydrogen, knocking is eliminated or the exhaust temperature decreases. Catalyst protection can be realized, and in cases other than the above in the high load region, operation using only gasoline as fuel can be performed. For this reason, according to the system of the present embodiment, it is possible to enjoy the advantage of using hydrogen as fuel together with gasoline or in place of gasoline, while reducing the total amount of hydrogen used as compared with the system of the embodiment.

Embodiment 3 FIG.
Next, a third embodiment of the present invention will be described with reference to FIG.
The system of the present embodiment is realized by causing the routine shown in the ECU 50 to be executed using the apparatus configuration of the first embodiment described above.

  The system of the present embodiment is that when acceleration is performed in the normal operation region, the hydrogen fuel in-cylinder injection valve 30 is selected instead of the hydrogen fuel port injection valve 28 at the beginning of the acceleration. Except for this, the processing is the same as that of the first embodiment.

  When hydrogen is added at the time of acceleration, it is preferable to increase the hydrogen addition amount as the gasoline injection amount is increased. However, hydrogen, which is a gaseous fuel, has a larger volume than gasoline, which is a liquid fuel. For this reason, when the injection amount is increased in the intake port 18 at the same time, the followability of the hydrogen fuel port injection valve 28 is not as good as that of the gasoline injection valve 26. On the other hand, the hydrogen fuel in-cylinder injection valve 30 has a higher injection pressure than the hydrogen fuel port injection valve 28. For this reason, according to the hydrogen fuel in-cylinder injection valve 30, higher followability can be obtained when the amount of hydrogen is increased than when a hydrogen fuel port injection valve is used. Therefore, in the system of the present embodiment, in the normal operation region, the increase can be followed by the hydrogen fuel port injection valve 28 from the time when acceleration is started until the predetermined injection valve change period elapses. Until this happens, the hydrogen fuel port injection valve 28 is switched to the hydrogen fuel in-cylinder injection valve 30.

  FIG. 5 is a flowchart of a routine executed by the ECU 50 shown in FIG. 1 in order to select a suitable injection valve in accordance with the operating state of the internal combustion engine 10 and execute fuel injection in the third embodiment. In FIG. 5, the same steps as those shown in FIG. 3 in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.

In the routine shown in FIG. 5, when it is determined that the vehicle is not in the high load region (step 108), the engine speed is acquired (step 124), and the acceleration condition is determined based on the engine speed and the throttle opening. It is determined whether or not it is established (step 126).
As a result, if it is determined in step 126 that the acceleration condition is not satisfied, the gasoline injection valve 26 and the hydrogen fuel port injection valve 28 are selected as injection valves (step 110).

  On the other hand, if it is determined in step 126 that the acceleration condition is satisfied, fuel injection by the gasoline injection valve 26 and the hydrogen fuel port injection valve 28 is performed until a predetermined injection valve change period t elapses. Instead, fuel injection by the gasoline injection valve 26 and the hydrogen fuel in-cylinder injection valve 30 is selected (step 128).

  The injection valve change period t used in step 128 is a period to be determined according to the acceleration state. That is, when the amount of change in the throttle opening is large, a high follow-up performance when the amount of fuel is increased is required. For this reason, it is desirable that the change period t is set longer as the amount of change in the throttle opening is larger. Further, when the vehicle is accelerated rapidly, that is, when the change rate of the throttle opening is large, the followability is required to be high. For this reason, it is desirable that the change period t is set longer as the change rate of the throttle opening is larger. The ECU 50 stores a map in which the injection valve change period t is defined by the relationship between the amount of change in the throttle opening and the rate of change so as to satisfy the above requirement. Specifically, in step 128, the injection valve change period t is set with reference to the map.

In step 128, when the predetermined injection valve change period t has elapsed, the gasoline injection valve 26 and the hydrogen fuel port injection valve 28 are selected as injection valves (step 110).
According to the processing of the routine shown in FIG. 5 described above, hydrogen can be supplied with good response by switching from the hydrogen fuel port injection valve 28 to the hydrogen fuel in-cylinder injection valve 30 at the initial stage of acceleration. Moreover, according to the above process, the followability at the time of hydrogen supply can be ensured irrespective of the acceleration state.

It is a figure for demonstrating the structure of the internal combustion engine of Embodiment 1 of this invention. It is a figure for demonstrating the operating method of the internal combustion engine performed in Embodiment 1 of this invention. It is a flowchart of the routine performed in Embodiment 1 of the present invention. It is a flowchart of the routine performed in Embodiment 2 of this invention. It is a flowchart of the routine performed in Embodiment 3 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 18 Intake port 22 Intake valve 26 Gasoline injection valve 28 Hydrogen fuel port injection valve 30 Hydrogen fuel cylinder injection valve 36 Pump 44 Primary regulator 46 Secondary regulator 50 ECU (Electronic Control Unit)

Claims (7)

A main fuel injection valve for injecting main fuel;
A hydrogen fuel port injection valve for injecting hydrogen fuel into the intake port;
A hydrogen fuel in-cylinder injection valve for injecting hydrogen fuel into the cylinder;
An injection valve selection means for selecting an injection valve to be used for fuel injection from the main fuel injection valve, the hydrogen fuel port injection valve, and the hydrogen fuel in-cylinder injection valve according to the operating state of the internal combustion engine;
Fuel injection execution means for executing fuel injection using the injection valve selected by the injection valve selection means;
A control device for an internal combustion engine, comprising: The injection valve selection means, when starting the internal combustion engine, selects fuel injection only by the hydrogen fuel cylinder injection valve,
2. The control apparatus for an internal combustion engine according to claim 1, wherein the fuel injection execution means executes fuel injection so that stratified operation is realized. The main fuel injection valve is an injection valve that injects main fuel into the intake port;
2. The control apparatus for an internal combustion engine according to claim 1, wherein the injection valve selection means selects fuel injection by the main fuel injection valve and the hydrogen fuel port injection valve during normal operation of the internal combustion engine.   The injection valve selection means selects fuel injection by the main fuel injection valve and the hydrogen fuel in-cylinder injection valve from when acceleration is started until a predetermined injection valve change period elapses. The control apparatus for an internal combustion engine according to claim 3, wherein the control apparatus is an internal combustion engine. The injection valve selection means selects fuel injection by the main fuel injection valve and the hydrogen fuel in-cylinder injection valve at the time of high load of the internal combustion engine,
2. The control apparatus for an internal combustion engine according to claim 1, wherein the fuel injection execution unit starts fuel injection from the hydrogen fuel in-cylinder injection valve after the intake valve is closed. The injection valve selection means selects fuel injection by the main fuel injection valve and the hydrogen fuel in-cylinder injection valve when knocking is detected,
2. The control apparatus for an internal combustion engine according to claim 1, wherein the fuel injection execution unit starts fuel injection from the hydrogen fuel in-cylinder injection valve after the intake valve is closed. The injection valve selection means selects fuel injection by the main fuel injection valve and the hydrogen fuel in-cylinder injection valve when the exhaust gas temperature exceeds a predetermined upper limit value,
2. The control apparatus for an internal combustion engine according to claim 1, wherein the fuel injection execution unit starts fuel injection from the hydrogen fuel in-cylinder injection valve after the intake valve is closed.

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