JP2006220110A - Fuel control device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel control device for an engine capable of ensuring excellent engine startability when an opening failure occurs to a hydrogen-injection valve in a dual-fuel engine equipped with a hydrogen-injection valve for injecting and supplying gaseous hydrogen and a gasoline-injection valve for injecting and supplying gasoline. <P>SOLUTION: The fuel control device for the engine equipped with the hydrogen-injection valve for injecting and supplying gaseous hydrogen, and a gasoline-injection valve for injecting and supplying gasoline, is provided with a failure-detecting means for detecting the opening failure in which the hydrogen-injection valve is left open; a shut-off valve provided upstream of the hydrogen-injection valve in a hydrogen supply passage communicating with the hydrogen-injection valve and controlling the supply of hydrogen to the hydrogen-injection valve; and a control means for closing the shut-off valve and switching a fuel supply source to the gasoline-injection valve from the hydrogen-injection valve in the case of detecting the opening failure by the failure-detecting means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an engine fuel control device for controlling fuel supply into a combustion chamber in an engine including a hydrogen injection valve for supplying gaseous hydrogen and a gasoline injection valve for supplying gasoline.

  In recent years, for the purpose of reducing pollution, vehicles equipped with engines that are used as gaseous fuels such as compressed natural gas, liquefied propane gas, and compressed hydrogen have been developed. In an engine using gaseous fuel, in general, gaseous fuel has characteristics such as an extremely large volume ratio compared to gasoline and a high combustion rate (especially for gaseous hydrogen). It is relatively difficult to secure the amount and control the supply amount of gaseous fuel. At the time of engine start, the gas mixture that has increased in hydrogen concentration due to the addition of new gaseous hydrogen to the gaseous hydrogen remaining in the intake system burns in the intake system. Phenomenon (so-called backfire), and when the engine starts, there is a possibility that a mixture containing unburned gaseous hydrogen remaining in the exhaust system burns in the exhaust system (so-called afterburn). Measures to eliminate it are necessary. As one of such measures, conventionally, for example, in Japanese Patent Application Laid-Open No. 5-214937, a shutoff valve is provided in a hydrogen supply passage upstream of a hydrogen supply valve, and the shutoff valve is closed at the time of engine stall, thereby providing backfire and afterburning. It has been proposed to avoid.

JP-A-5-214937

  By the way, particularly in an engine using gaseous hydrogen, a hydrogen injection valve that injects gaseous hydrogen into the combustion chamber is used. However, a failure that does not return to the closed state while the hydrogen injection valve is open (hereinafter referred to as an open failure) occurs. If it occurs, hydrogen leaks into the combustion chamber. The gaseous hydrogen leaking into the working chamber flows into the intake system and the exhaust system without being burned, and can cause backfire and afterburn. In order to suppress the influence of hydrogen leakage caused by the open failure of the hydrogen injector, it is desirable to first grasp the state of the hydrogen injector and accurately detect the open failure of the hydrogen injector. In the event of an open failure, it is desirable to ensure good engine startability. In addition, in the said patent document 1, the indication and the suggestion about the technique which copes with the open failure of a hydrogen injection valve are not performed.

  The present invention has been made in view of the above technical problem. In particular, in a dual fuel engine having a hydrogen injection valve for supplying gaseous hydrogen and a gasoline injection valve for supplying gasoline, an open failure occurs in the hydrogen injection valve. An object of the present invention is to provide an engine fuel control device capable of ensuring good engine startability in the case of occurrence of the problem.

  The invention according to claim 1 of the present application is an engine fuel control device including a hydrogen injection valve that injects gaseous hydrogen and a gasoline injection valve that injects and supplies gasoline, and the hydrogen injection valve remains open. A failure detecting means for detecting an open failure; a shutoff valve provided upstream of the hydrogen injector in a hydrogen supply passage communicating with the hydrogen injector; and controlling the hydrogen supply to the hydrogen injector; And a control means for closing the shutoff valve and switching the fuel supply source from the hydrogen injection valve to the gasoline injection valve when an open failure is detected by the detection means. is there.

  Further, in the invention according to claim 2 of the present application, in the invention according to claim 1, when an open failure is detected by the failure detection means, the control means stops the ignition for a predetermined time from the detection time and performs scavenging. And after scavenging, the fuel supply source is switched from the hydrogen injection valve to the gasoline injection valve.

  Furthermore, the invention according to claim 3 of the present application is the invention according to claim 1 or 2, further comprising hydrogen detection means for detecting the presence of hydrogen on the exhaust side, wherein the control means is the hydrogen detection means. When the presence of hydrogen is no longer detected, the fuel supply source is switched from the hydrogen injection valve to the gasoline injection valve.

  Further, the invention according to claim 4 of the present application is the invention according to claim 3, wherein the hydrogen detection means is constituted by an oxygen concentration sensor provided in an exhaust passage communicating with the combustion chamber. It is what.

  Furthermore, the invention according to claim 5 of the present application is the invention according to any one of claims 1 to 4, further comprising pressure detection means for detecting the pressure between the hydrogen injection valve and the shutoff valve. In addition, the control means opens the shut-off valve temporarily upon engine start and closes the shut-off valve, and the failure detection means closes the shut-off valve by the control means upon engine start-up. Then, an open failure is detected based on a change in pressure detected by the pressure detecting means.

  According to the first aspect of the present invention, when an open failure of the hydrogen injector is detected, good engine startability can be ensured by supplying gasoline.

  Further, according to the invention according to claim 2 of the present application, since the switching to the gasoline supply is performed after the scavenging of hydrogen, an engine that is more favorable by the gasoline supply while suppressing the occurrence of abnormal combustion such as afterburn due to residual hydrogen. Startability can be ensured.

  Furthermore, according to the invention according to claim 3 of the present application, after the hydrogen scavenging, when it is confirmed that the presence of hydrogen has actually disappeared, switching to gasoline supply is performed. Good engine startability can be secured by supplying gasoline while more reliably suppressing abnormal combustion.

  Furthermore, according to the invention according to claim 4 of the present application, by using an existing oxygen concentration sensor, the presence of hydrogen remaining in the exhaust passage is detected, and the occurrence of abnormal combustion such as afterburning is suppressed. can do.

  Furthermore, according to the invention of claim 5 of the present application, it is possible to detect an open failure of the hydrogen injection valve when starting the engine.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a diagram schematically showing a rotary type hydrogen engine according to an embodiment of the present invention. The hydrogen engine 1 has a rotor housing H ₁ having a trochoidal inner peripheral surface and a substantially flat side housing H ₂ that extends along the plane direction of the rotor R as an outer configuration. . In a state where the housings H ₁ and H ₂ are combined and the rotor R is housed in an internal space formed inside the housings H ₁ and H ₂ , the inner surface of the rotor housing H ₁ , the side housing H ₂ , Thus, three combustion chambers (hereinafter referred to as working chambers) E ₁ , E ₂ , E ₃ are defined. Each working chamber E ₁ , E ₂ , E ₃ repeats expansion and contraction as the rotor R rotates about the eccentric shaft C, and each working chamber E ₁ , E ₂ , E ₃ , intake stroke in E _3, compression stroke, expansion stroke, a series of stroke is completed consisting exhaust stroke.

The rotor housing H ₁ includes a gaseous hydrogen injection valve (hereinafter referred to as a direct injection hydrogen injector) I ₁ that directly injects gaseous hydrogen into the working chambers E ₁ , E ₂ , E ₃ , and working chambers E ₁ , E _2. , the spark plug 7 for igniting the air-fuel mixture consisting of supplied fuel (gaseous hydrogen or gasoline) and air in E _3, are provided. On the other hand, the side housing H ₂ is formed with an intake port 2 a communicating with the intake passage 2 and an exhaust port 3 a communicating with the exhaust passage 3.

Furthermore, in this embodiment, in addition to the direct injection type hydrogen injector I ₁ provided in the rotor housing H ₁ , a gasoline injection valve I ₂ (hereinafter referred to as port injection) that is attached to the intake passage 2 and injects gasoline into the intake passage 2. with that formula gasoline injector I ₂₎ is provided, on its upstream side, likewise attached to the intake passage 2, a hydrogen injector I ₃ for injecting gaseous hydrogen into the intake passage 2 _{(hereinafter,} port injection hydrogen injector I ₃ ). When the fuel supply to the working chamber of the hydrogen engine 1 is required, the fuel can be directly adjusted according to various conditions such as the engine speed, the remaining amount of hydrogen or gasoline, or according to the driver's request. An appropriate one is selected from the injection type hydrogen injector I ₁ , the port injection type gasoline injector I ₂ , and the port injection type hydrogen injector I ₃ .

FIG. 2 is a diagram conceptually showing the hydrogen engine 1 and the configuration related thereto. As can be seen from this figure, solenoid valves V ₁ , V _2, and V ₃ are attached to the direct injection hydrogen injector I ₁ , the port injection type gasoline injector I _2, and the port injection type hydrogen injector I ₃ , respectively. The fuel injection in the injector is controlled based on the opening / closing operation of each solenoid valve. In FIG. 2, the electromagnetic valves V ₁ , V ₂ , and V ₃ are separately provided for the injectors I ₁ , I ₂ , and I ₃ . Built in.

  As shown in FIG. 2, in the present embodiment, with respect to the main body of the hydrogen engine 1, a water temperature sensor 18 for detecting the coolant temperature of the engine 1 and an engine rotation for detecting the engine speed. A number sensor 19 is provided. The intake passage 2 is provided with an intake air temperature sensor 21 that detects the temperature of the air flowing in the intake passage 2, while the exhaust passage 3 detects an oxygen concentration so as to calculate the air-fuel ratio in the working chamber. For this purpose, an oxygen concentration sensor (so-called λ sensor) 22 is provided.

Further, as shown in FIG. 2, the direct injection hydrogen injector I ₁ provided in the rotor housing H ₁ constituting the engine body and the port injection hydrogen injector I ₃ attached to the intake passage 2 include a hydrogen supply pipe 9. Is connected to a hydrogen storage tank 14 for storing gaseous hydrogen. On the other hand, the port injection type gasoline injector I ₂ attached to the intake passage 2 is connected to a gasoline storage tank (not shown) via a gasoline supply pipe 13. The discharge port of the hydrogen storage tank 14 is provided with a stop valve 15 that is controlled to be opened and closed to control hydrogen discharge from the hydrogen storage tank 14 to the hydrogen supply pipe 9. Further, in the hydrogen supply pipe 9, a shutoff valve 16 is provided on the upstream side of the direct injection type hydrogen injector I ₁ and the port injection type hydrogen injector I ₃ to open and close to control the hydrogen supply to each injector. Further, hydrogen is supplied into the hydrogen supply pipe 9 between the shutoff valve 16, the direct injection type hydrogen injector I ₁ and the port injection type hydrogen injector I _{3 in} order to calculate the remaining amount of hydrogen in the hydrogen storage tank 14. A pressure sensor 17 for detecting the residual pressure in the pipe 9 is provided.

  Although not particularly shown, the configuration related to the hydrogen engine 1 includes an air cleaner provided in the intake passage 2, an air flow sensor for detecting the intake air amount, and opening / closing according to the amount of depression of an accelerator pedal (not shown). Throttle valve that throttles air, a throttle opening sensor that detects the opening of the throttle valve, a surge tank that stabilizes the air flow, an exhaust gas purification catalyst provided in the exhaust passage 3, an exhaust temperature sensor And other components such as a fuel flow meter that is provided in the hydrogen supply passage 9 or the gasoline supply passage 13 and detects the flow rate of the fuel supplied to the various injectors.

Further, as shown in FIG. 2, a control unit 10 is provided for controlling the hydrogen engine 1 and the related configuration as described above. The control unit 10 is a comprehensive control device for the hydrogen engine 1 comprising a computer, and includes an intake air amount detected by an air flow sensor, an engine water temperature detected by a water temperature sensor 18, a throttle opening sensor, and an idle switch. (A switch that is turned on when the accelerator pedal is fully closed, but not shown here), the throttle opening detected by the engine speed sensor 19, the engine speed detected by the engine speed sensor, the exhaust temperature detected by the exhaust temperature sensor, Based on various control information such as the fuel flow rate to the injector detected by the fuel flow meter, various controls such as fuel injection control and ignition timing adjustment control of the engine 1 are performed, and a hydrogen injector (direct injection type hydrogen) described later Injector I ₁ and port injection type hydrogen injector The failure detection process and the fuel supply control process of I ₃ ) are performed. The control unit 10 has a microcomputer (not shown) therein, and correction and calculation executed when various controls including drive control of the injectors I ₁ , I ₂ , and I ₃ are performed. Processing such as determination is performed by the microcomputer.

Then, in the hydrogen engine 1, the direct-injection hydrogen injector I ₁ and the port-injection hydrogen injector I ₃ are selectively used in accordance with the engine rotational speed detected by the engine speed sensor 19, also the injection timing is changed The control by the control unit 10 will be described. FIG. 3 is an explanatory diagram showing a hydrogen injector employed according to each engine speed and its injection timing. First, in the low rotation region (about 800 to 2500 rpm), the direct injection type hydrogen injector I ₁ is employed, and injection in the compression stroke is executed. Here, when gaseous hydrogen with a large volume is supplied during the intake stroke, the problem is that the volume of hydrogen does not allow air to sufficiently enter the working chamber via the intake port 2a. During the stroke, gaseous hydrogen is supplied, and a decrease in fuel charging efficiency is suppressed.

Further, in the middle speed region (approximately 2500～5000Rpm), is adopted direct-injection hydrogen injector _{I 1,} it is executed injection in the intake stroke. Here, in order to cope with the problem that abnormal combustion occurs when ignition is performed with the gaseous hydrogen and air separated, the gaseous hydrogen is injected from the direct injection hydrogen injector I ₁ at an early stage of the intake stroke, and the mixing time is reached. By ensuring this, the mixing property of gaseous hydrogen and air is improved.

Finally, in the high rotation region (about 5000～7000Rpm), the direct-injection hydrogen injector _{I 1} and the port-injection hydrogen injector _{I 3} are combined. Here, the port injection type hydrogen injector I ₃ is used to improve the mixing property between gaseous hydrogen and air, and the premixed injection is executed. At the same time, the direct injection type hydrogen injector I ₁ is used to suppress the torque drop. Are used to perform injection in the compression stroke. As an example, the ratio of hydrogen feed is 80% the amount supplied from the port injection hydrogen injector I _3, the supply amount from the direct-injection hydrogen injector I ₁ is 20%.

By the way, as described above, when an open failure that does not return to the closed state occurs in the direct injection type hydrogen injector I ₁ and the port injection type hydrogen injector I ₃ , hydrogen leaks into the combustion chamber, causing backfire and after-treatment. In this embodiment, in order to suppress the influence of hydrogen leakage due to an open failure as much as possible, and to ensure good engine startability even when an open failure occurs, in the present embodiment, Such failure detection processing and fuel supply control processing of the hydrogen injectors I ₁ and I ₃ are executed.

First, as a failure detection process for the hydrogen injectors I ₁ and I ₃ , the engine shuts down after the shut-off valve 16 is temporarily opened and closed with the engine start, and the subsequent shut-off valve 16 and the hydrogen injectors I ₁ and I ₃ A process of observing a change in pressure during this period and determining that an open failure of the hydrogen injector I ₁ or I ₃ has occurred when a predetermined condition is satisfied is executed.

As a fuel supply control process for ensuring good engine startability, when an open failure of the hydrogen injector I ₁ or I ₃ is detected, the shutoff valve 16 is closed and ignition by the spark plug 7 is performed in a predetermined manner. After the scavenging, the fuel supply source is switched from the hydrogen injector I ₁ or I ₃ to the gasoline injector I ₂ after the scavenging. Furthermore, as the fuel supply control process, to ensure the engine startability without abnormal combustion, when the presence of hydrogen by the oxygen concentration sensor 22 is not detected, the fuel supply source of hydrogen injector I ₁ or I ₃ process of switching to the gasoline injector I ₂ is performed.

FIG. 4 is a time chart showing changes in various parameters during execution of the failure detection process of the hydrogen injectors I ₁ and I ₃ described above. Here, a change in an open failure flag (FLAG) indicating an on / off state of an ignition switch (not shown), an open / close state of the shutoff valve 16, a hydrogen pressure detected by the pressure sensor 17, and an open failure occurrence state is shown. .

As the ignition switch is turned on from the off state and the engine is started, the shutoff valve 16 in the closed state is temporarily opened. As the shut-off valve 16 is opened, the hydrogen pressure between the shut-off valve 16 and the hydrogen injectors I ₁ and I ₃ detected by the pressure sensor 17 gradually increases. Thereafter, the shutoff valve 16 is closed, and the hydrogen pressure P1 at that time is detected. And the change of the hydrogen pressure after that is observed.

More specifically, the difference (P1-P2) between the hydrogen pressure P1 and the hydrogen pressure P2 after the shutoff of the shutoff valve 16 is calculated, and a change in this difference is observed. Then, as shown by the solid line, if P2 is substantially constant without change from P1, i.e., if the P1-P2 is approximately 0, no leakage of hydrogen from the hydrogen injector I ₁ and I _3, normally they It is judged that it is functioning. Also, whereas, as shown by the broken line, the hydrogen pressure P2 decreases, if the difference (P1-P2) is it becomes greater than the predetermined value t, at which time, the hydrogen leakage occurs from the hydrogen injector I ₁ and I _3, these Is not functioning properly. Along with this determination, the failure flag (FLAG) is set from 0 to 1.

  5A and 5B are flowcharts of a hydrogen injector failure detection process and a fuel supply control process executed by the control unit 10 when the engine is started. In this process, first, for example, various signals detected by the configuration related to the hydrogen engine 1 shown in FIG. 2 are read (# 11), and based on those signals, whether or not the hydrogen engine 1 is started, that is, an ignition. Whether or not is turned on from the off state is determined (# 12). As a result, if it is determined that the hydrogen engine 1 has not been started, the process returns to step # 11, and the subsequent steps are repeated. On the other hand, if it is determined that the hydrogen engine 1 has been started, step S11 is performed. Proceed to # 13.

At step # 13, further, it is determined whether or not a failure of the hydrogen injector I ₁ and I ₃ has already been detected, as a result, when a failure is determined to be already detected, circles in FIG. 5A numbers 1 Then, the process proceeds to step # 26 in FIG. 5B. Step # 26 and subsequent steps will be described later. On the other hand, if it is determined that no failure has been detected, the shutoff valve 16 is continuously opened (# 14), and the first counter is further increased by 1 (C1 ← C1 + 1). (# 15).

After step # 15, it is determined whether or not the first counter is greater than a predetermined value (# 16). As a result, when it is determined that the first counter is equal to or smaller than the predetermined value, the process immediately returns. On the other hand, if it is determined that the first counter is greater than the predetermined value, the shutoff valve 16 is closed (# 17), and at that time, the pressure sensor 17 causes the shutoff valve 16 and the hydrogen injector I _1. and the hydrogen pressure P1 (see FIG. 4) is detected between the _{I 3} (# 18). Then, the second counter is incremented by 1 (C2 ← C2 + 1) (# 19).

After step # 19, it is determined whether the second counter is greater than a predetermined value (# 20). As a result, if it is determined that the second counter is equal to or smaller than the predetermined value, the process immediately returns. Also, whereas, if the second counter is determined to be larger than the predetermined value continues, at that time, the hydrogen pressure between the shut-off valve 16 and the hydrogen injectors I ₁ and I ₃ by the pressure sensor 17 P2 ( 4) is detected (# 21).

  After step # 21, it is determined whether the difference (P1-P2) between the hydrogen pressures P1 and P2 is greater than a predetermined value (# 22). As a result, if it is determined that P1-P2 is greater than the predetermined value, it is determined that a failure has occurred, and the failure flag (FLAG) is set to 1 (# 23), while P1-P2 is set to the predetermined value. If it is determined that the following is true, the failure flag is held at 0 because there is no abnormality (# 24). After both steps # 23 and # 24, the first and second counters are reset (# 25). The process is returned as above.

In step # 26, it is determined whether or not the failure flag is 1. As a result, if it is determined that the failure flag is 0, the process proceeds to step # 36. If it is determined that there is a shutoff valve 16 is continuously being closed (# 27), the hydrogen injector I ₁ or I ₃ is opened (# 28), as a result, the ignition is stopped (# 29). Then, the third counter is incremented by 1 (C3 ← C3 + 1) (# 30).

After step # 30, it is determined whether the third counter is greater than a predetermined value (# 31). As a result, if it is determined that the third counter is equal to or smaller than the predetermined value, the process immediately returns. On the other hand, if it is determined that the third counter is larger than the predetermined value, it is subsequently determined whether or not the oxygen concentration detected by the oxygen concentration sensor 22 is smaller than the predetermined value (# 32). As a result, when it is determined that the oxygen concentration is equal to or higher than the predetermined value, the process immediately returns. On the other hand, when it is determined that the oxygen concentration is lower than the predetermined value, the hydrogen injector I ₁ or I ₃ is closed. Accordingly, the gas injector I2 is opened (# 34). Then, the third counter is reset (# 35).

After step # 36, it is first determined whether or not the hydrogen pressure detected by the pressure sensor 17 (see FIG. 2) is greater than 0.5 MPa (# 36). As a result, the residual hydrogen pressure is 0.5 MPa. If it is determined that the amount is below, the remaining hydrogen amount in the hydrogen storage tank 14 is not sufficient, and the process proceeds to step # 32, and the subsequent steps described above are performed. On the other hand, if it is determined that the hydrogen pressure is greater than 0.5 MPa, the shutoff valve 16 is continuously opened assuming that the hydrogen remaining amount in the hydrogen storage tank 14 is sufficient (# 37), As described with reference to FIG. 3, the direct injection type hydrogen injector I ₁ and the port injection type hydrogen injector I ₃ are switched according to the engine speed (# 38). The process is returned as above.

  In the above-described embodiment, the hydrogen injector failure detection process and the fuel supply control process are executed when the engine is started. However, the present invention is not limited to this, and the process may be executed when the engine is stopped, for example. FIG. 6 is a flowchart of a hydrogen injector failure detection process and a fuel supply control process executed by the control unit 10 when the engine is stopped. In this process, first, for example, various signals detected by the configuration related to the hydrogen engine 1 shown in FIG. 2 are read (# 41), and based on those signals, whether or not the hydrogen engine 1 is stopped, that is, an ignition. Whether or not is turned off from the on state is determined (# 42). As a result, if it is determined that the hydrogen engine 1 is not stopped, the process returns to step # 41, and the subsequent steps are repeated. On the other hand, if it is determined that the hydrogen engine 1 is stopped, Proceed to # 43.

At step # 43, the failure of the hydrogen injector I ₁ or I ₃ is already determined whether detected, as a result, when a failure is determined to be already detected, the process is immediately returned. On the other hand, if it is determined that no failure has been detected, the shutoff valve 16 is continuously opened (# 44), and the first counter is further increased by 1 (C1 ← C1 + 1). (# 45).

After step # 45, it is determined whether or not the first counter is greater than a predetermined value (# 46). As a result, when it is determined that the first counter is equal to or smaller than the predetermined value, the process immediately returns. On the other hand, when it is determined that the first counter is larger than the predetermined value, the shutoff valve 16 is closed (# 47), and at that time, the pressure sensor 17 causes the shutoff valve 16 and the hydrogen injector I _1. and the hydrogen pressure P1 (see FIG. 4) is detected between the _{I 3} (# 48). Then, the second counter is incremented by 1 (C2 ← C2 + 1) (# 49).

After step # 49, it is determined whether the second counter is greater than a predetermined value (# 50). As a result, if it is determined that the second counter is equal to or smaller than the predetermined value, the process immediately returns. Also, whereas, if the second counter is determined to be larger than the predetermined value continues, at that time, the hydrogen pressure between the shut-off valve 16 and the hydrogen injectors I ₁ and I ₃ by the pressure sensor 17 P2 ( 4) is detected (# 51).

  After step # 51, it is determined whether the difference (P1-P2) between the hydrogen pressures P1 and P2 is greater than a predetermined value (# 52). As a result, if it is determined that P1-P2 is greater than the predetermined value, it is determined that a failure has occurred, and the failure flag (FLAG) is set to 1 (# 53), while P1-P2 is set to the predetermined value. If it is determined that the following is true, the failure flag is set to 0 because there is no abnormality (# 54). After both steps # 53 and # 54, the first and second counters are reset (# 55). The process is returned as above.

  FIG. 7 is a flowchart of processing executed when the engine is started, corresponding to the processing shown in FIG. In this process, first, for example, various signals detected by the configuration related to the hydrogen engine 1 shown in FIG. 2 are read (# 61), and based on those signals, whether or not the hydrogen engine 1 is stopped, that is, an ignition. Whether or not is turned on from the off state is determined (# 62). As a result, if it is determined that the hydrogen engine 1 has not been started, the process returns to step # 61, and the subsequent steps are repeated. On the other hand, if it is determined that the hydrogen engine 1 has been started, step S61 is performed. Proceed to # 63.

In step # 63, it is determined whether or not the failure flag is 1. As a result, if it is determined that the failure flag is 0, the process proceeds to step # 68. If it is determined that there is, the shutoff valve 16 is continuously closed (# 64), and then a failure display for notifying the driver of the occurrence of the failure is performed (# 65). As this failure display, for example, a message “hydrogen injector failure” may be displayed on a vehicle-mounted monitor, or an alarm lamp incorporated in an instrument panel together with an instrument such as a tachometer may be turned on. After the step # 65, the hydrogen injector _{I 1} or _{I 3} is closed (# 66), the gasoline injector _{I 2} is in the open state. The process is returned as above.

After step # 68, it is first determined whether or not the hydrogen pressure detected by the pressure sensor 17 (see FIG. 2) is greater than 0.5 MPa (# 68). As a result, the residual hydrogen pressure is 0.5 MPa. If it is determined that the amount of hydrogen is below, the remaining hydrogen amount in the hydrogen storage tank 14 is not sufficient, and the process proceeds to step # 66, and the subsequent steps described above are performed. On the other hand, if it is determined that the hydrogen pressure is greater than 0.5 MPa, it is assumed that the remaining amount of hydrogen in the hydrogen storage tank 14 is sufficient, and as described with reference to FIG. The direct injection type hydrogen injector I ₁ and the port injection type hydrogen injector I ₃ are switched according to the number (# 69). The process is returned as above.

As described with reference to FIGS. 5A and 5B, when the failure detection process and the fuel supply control process of the hydrogen injectors I ₁ and I ₃ are executed at the time of engine start, a change in pressure is observed for the failure detection process. When the shutoff valve 16 is closed above, the output stops, or when an open failure of the hydrogen injectors I ₁ and I ₃ is detected, the air-fuel ratio changes according to switching to the gasoline injector I ₂ . However, the change in output accompanying this may cause a sense of incongruity to the driver. However, as described with reference to FIGS. 6 and 7, the failure of the hydrogen injectors I ₁ and I ₃ when the engine is stopped. When executing the detection process and the fuel supply control process, the driver may recognize the output stop or output change as a phenomenon when the engine is stopped. It is possible to suppress such discomfort.

As is apparent from the above description, according to the present invention, the engine is started, the shutoff valve 16 is temporarily opened and then closed, and the subsequent shutoff valve 16 and the hydrogen injectors I ₁ and I ₃ are closed. Since the open failure of the hydrogen injector I ₁ or I ₃ is detected based on the change in the pressure of the fuel, the open failure of the hydrogen injector is detected while suppressing the influence of hydrogen leakage from the hydrogen injector into the combustion chamber. Can do. In addition, when an open failure of the hydrogen injector I ₁ or I ₃ is detected, the fuel supply source is switched from the hydrogen injector I ₁ or I ₃ to the gasoline injector I ₂ after scavenging hydrogen, so that an abnormality such as afterburning occurs. It is possible to start with gasoline while preventing combustion, and to ensure good engine startability. In addition, after the scavenging of hydrogen, switching to the gasoline injector I ₂ is performed when it is confirmed by the oxygen concentration sensor 22 that there is actually no hydrogen present, so that good engine startability can be ensured more reliably. Can do.

  Note that the present invention is not limited to the illustrated embodiment, and it is needless to say that various improvements and design changes can be made without departing from the gist of the present invention. For example, in the above-described embodiment, the rotary engine is taken up as the hydrogen engine 1, but the present invention is not limited to this, and the present invention can also be applied to a reciprocating engine.

  The fuel control apparatus for an engine according to the present invention is applicable to any apparatus as long as it includes a vehicle such as an automobile and is equipped with a dual fuel engine equipped with a hydrogen injector and a gasoline injector.

1 is a diagram schematically showing a hydrogen engine according to an embodiment of the present invention. FIG. 2 is a diagram conceptually showing the hydrogen engine and a configuration related thereto. It is explanatory drawing showing the hydrogen injector employ | adopted according to each engine speed, and its injection timing. It is a time chart showing the change of various parameters during execution of failure detection processing of a hydrogen injector. It is a 1st flowchart about the failure detection process of a hydrogen injector and the fuel supply control process which are performed at the time of engine starting by a control unit. 6 is a second flowchart of a hydrogen injector failure detection process and a fuel supply control process executed by the control unit when starting the engine. 5 is a flowchart of a hydrogen injector failure detection process and a fuel supply control process executed by the control unit when the engine is stopped. It is a flowchart about the process performed at the time of engine starting corresponding to the process shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Engine main body, 2 ... Intake passage, 3 ... Exhaust passage, 4 ... Injector main body, 5 ... Needle valve, 6 ... Solenoid coil, 7 ... Spark plug, 9 ... Hydrogen supply passage, 10 ... Control unit, 13 ... Gasoline supply passage, 14 ... hydrogen storage tank, 15 ... stop valve, 16 ... shutoff valve, 17 ... pressure sensor, 18 ... water temperature sensor, 19 ... engine speed sensor, 21 ... intake air temperature sensor, 22 ... oxygen sensor, _{I 1} ... Direct injection type hydrogen injector, I ₂ ... port injection type gasoline injector, I ₃ ... port injection type hydrogen injector, V ₁ , V ₂ , V ₃ ... solenoid valve.

Claims (5)

In an engine fuel control apparatus comprising a hydrogen injection valve for supplying gaseous hydrogen and a gasoline injection valve for supplying gasoline,
A failure detection means for detecting an open failure in which the hydrogen injection valve remains open;
A shutoff valve that is provided upstream of the hydrogen injection valve in a hydrogen supply passage that communicates with the hydrogen injection valve and controls the supply of hydrogen to the hydrogen injection valve;
And a control means for closing the shutoff valve and switching the fuel supply source from the hydrogen injection valve to the gasoline injection valve when an open failure is detected by the failure detection means. Engine combustion control device.   When an open failure is detected by the failure detection means, the control means performs scavenging by stopping ignition for a predetermined time from the detection time, and after scavenging, switches the fuel supply source from the hydrogen injection valve to the gasoline injection valve. The fuel control apparatus for an engine according to claim 1. Furthermore, hydrogen detection means for detecting the presence of hydrogen on the exhaust side is provided,
The engine fuel control according to claim 1 or 2, wherein the control means switches the fuel supply source from the hydrogen injection valve to the gasoline injection valve when the presence of hydrogen is no longer detected by the hydrogen detection means. apparatus.   4. The fuel control apparatus for an engine according to claim 3, wherein the hydrogen detection means includes an oxygen concentration sensor provided in an exhaust passage communicating with the combustion chamber. Furthermore, pressure detecting means for detecting the pressure between the hydrogen injection valve and the shutoff valve is provided, and the control means opens the shutoff valve temporarily upon engine start and closes it. And
2. The failure detection means detects an open failure based on a change in pressure detected by the pressure detection means after the shut-off valve is closed by the control means as the engine starts. The fuel control apparatus of the engine as described in any one of -4.

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