JP2007303320A - Fuel injection device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection device for an engine capable of inhibiting erroneous detection of a leak detection means while enabling a cylinder fuel injection valve to easily open by reducing fuel pressure acting on the cylinder fuel injection valve. <P>SOLUTION: This device is provided with a pressure sensor 17 provided in a hydrogen supply pipe 9 and a control unit 10 detecting hydrogen leak from a gaseous fuel supply system including the hydrogen supply pipe 9 based on fuel pressure of gaseous hydrogen detected during engine start. The control unit 10 reduces fuel pressure of gaseous hydrogen after hydrogen leak detection during engine start. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention includes an in-cylinder fuel injection valve that directly injects gaseous fuel into a cylinder, a gaseous fuel tank, and a gaseous fuel supply passage. The gaseous fuel supply passage and the gaseous fuel tank and the in-cylinder fuel injection valve. The present invention relates to a fuel injection device for an engine that connects the two.

  Conventionally, an engine having a direct injection type in-cylinder fuel injection valve that directly injects gaseous fuel into a working chamber is known. In an engine equipped with such a direct-injection in-cylinder fuel injection valve, the moisture contained in the gas or the moisture generated by combustion when using gaseous fuel freezes as the outside air temperature decreases, There may be a problem that it adheres to the inner fuel injection valve and prevents its opening.

  Further, when lubricating oil is used to lubricate the rotation of the engine, there is a problem that the lubricating oil enters the in-cylinder fuel injection valve and prevents the in-cylinder fuel injection valve from opening.

  Further, in Patent Document 1 below, mist-like oil that has been mixed when gaseous fuel is filled into a fuel tank at high pressure adheres to the in-cylinder fuel injection valve, and the oil adheres to the cylinder fuel injection valve during cold start. It is described that the opening of the in-cylinder fuel injection valve may be hindered.

  In response to such a problem, for example, Patent Document 1 discloses that the fuel pressure (fuel pressure) applied to the in-cylinder fuel injection valve is reduced when the engine is stopped, thereby reducing the oil sticking force and opening the in-cylinder fuel injection valve. A method for facilitating the valve has been proposed.

Japanese Patent Laid-Open No. 2000-274312

  By the way, a gaseous fuel supply passage is provided between the fuel tank in which gaseous fuel is stored and the in-cylinder fuel injection valve, and a fuel pressure in the gaseous fuel supply passage is provided in the fuel tank. Some of them are equipped with a leak detection means for detecting a gaseous fuel leakage from a gaseous fuel supply system including the gaseous fuel supply passage.

  Here, if the method disclosed in Patent Document 1 is adopted in a device provided with a leakage detection means, the leakage detection means erroneously detects that the fuel pressure has been lowered by the above-described method. There is a risk that it will be detected as a state in which the occurrence of the error occurs.

  According to the present invention, the fuel injection of the engine that can reduce the fuel pressure applied to the in-cylinder fuel injection valve so that the in-cylinder fuel injection valve can be easily opened while suppressing the erroneous detection of the leak detection means. An object is to provide an apparatus.

  The fuel injection device for an engine according to the present invention includes an in-cylinder fuel injection valve that directly injects gaseous fuel into a cylinder, a gaseous fuel tank, and a gaseous fuel supply passage, and the gaseous fuel tank includes the gaseous fuel tank and the gaseous fuel tank. A fuel injection device for an engine connected to the in-cylinder fuel injection valve, the fuel pressure detecting means disposed in the gaseous fuel supply passage, and the gaseous fuel supply passage based on the fuel pressure detected when the engine is started And a fuel pressure correcting means for reducing the fuel pressure after the fuel leakage is detected by the leakage detecting means when the engine is started.

  According to this configuration, by reducing the fuel pressure when starting the engine, the action of the gaseous fuel that attempts to close the in-cylinder fuel injection valve is reduced, so that the in-cylinder fuel injection valve can be easily opened. it can.

  Furthermore, since the fuel pressure is reduced after the detection of the gaseous fuel leakage by the leakage detection means, the erroneous detection of the gaseous fuel leakage by the leakage detection means can be suppressed.

  In one embodiment of the present invention, there is provided temperature detecting means for detecting a temperature related to the in-cylinder fuel injection valve, and the fuel pressure correcting means is operated when the temperature is equal to or lower than a predetermined temperature. To do.

  According to this configuration, in particular, when the in-cylinder fuel injection valve cannot be opened due to freezing of water during cold, oil or lubricating oil, etc., the in-cylinder fuel is reduced by reducing the fuel pressure when starting the engine. The operation of the injection valve can be secured.

  In one embodiment of the present invention, the fuel pressure correcting means reduces the fuel pressure by increasing the volume of a gaseous fuel supply system capable of storing gaseous fuel when the engine is started.

  According to this configuration, the fuel pressure acting on the in-cylinder fuel injection valve can be easily reduced by increasing the volume of the gaseous fuel supply system.

  In one embodiment of the present invention, the fuel pressure correction means includes: a shut-off valve capable of relieving gaseous fuel in the gaseous fuel supply passage; and a volume portion capable of storing the gaseous fuel relieved from the shut-off valve. Is characterized in that when the engine is started, the shutoff valve is opened and the fuel pressure is reduced by storing the gaseous fuel in the volume portion.

  According to this configuration, the fuel pressure can be easily reduced only by opening control of the shut-off valve by storing the gaseous fuel relieved by the shut-off valve in the volume portion.

  In one embodiment of the present invention, a second gaseous fuel supply passage that connects the volume portion and the intake passage is provided, a purge valve is disposed in the second gaseous fuel supply passage, and the purge valve is disposed in the second gaseous fuel supply passage. A purge valve control means for opening the valve and discharging the stored gaseous fuel to the intake passage is provided.

  According to this configuration, effective use of the relieved gaseous fuel can be achieved.

  According to the present invention, at the time of starting the engine, after detecting the gaseous fuel leakage by the leakage detecting means, the fuel pressure is lowered, thereby suppressing the erroneous detection of the gaseous fuel leakage by the leakage detecting means, and the in-cylinder fuel injection valve. Can be easily opened.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram schematically showing a rotary type engine body 1 according to an embodiment of the present invention. The engine main body 1 includes a rotor housing H1 having a trochoidal inner peripheral surface and a substantially flat side housing H2 that extends along the planar direction of the rotor R, as an outer configuration. In a state where the housings H1 and H2 are combined and the rotor R is housed in an internal space formed therein, the rotor R is surrounded by the inner peripheral surface of the rotor housing H1 and the side housing H2. Working chambers E1 to E3 are defined. Each working chamber E1, E2, E3 repeats expansion and contraction with the rotation of the rotor R around the eccentric shaft C, and the intake stroke and compression are performed in each working chamber E1 to E3 during one rotation of the rotor R. A series of strokes including a stroke, an expansion stroke, and an exhaust stroke is completed.

  The rotor housing H1 includes a gaseous hydrogen injection valve I1 (hereinafter referred to as a direct injection hydrogen injector I1) that directly injects gaseous hydrogen into the working chambers E1 to E3, and fuel (gaseous hydrogen) supplied into the working chambers E1 to E3. ) And an ignition plug 8 for igniting an air-fuel mixture comprising air. On the other hand, in the side housing H2, an intake port 2a communicating with the intake passage 2 is formed, and an exhaust port 3a communicating with the exhaust passage 3 is formed.

  FIG. 2 is a diagram conceptually showing the engine body 1 and the configuration related thereto, and FIG. 3 is a block diagram showing a control system for controlling each configuration shown in FIG. The direct injection hydrogen injector I1 is provided with an electromagnetic valve V1, and hydrogen injection in the injector I1 is controlled based on the opening / closing operation of the electromagnetic valve V1. In FIG. 2, the solenoid valve V1 is shown to be provided separately from the injector I1, but actually, as shown in FIGS. 4 and 5 showing the cross-sectional structure of the direct injection hydrogen injector I1, A solenoid valve V1 is incorporated in the injector I1.

  As shown in FIG. 2, in the present embodiment, a water temperature sensor 18 for detecting the coolant temperature of the engine body 1 (engine water temperature) and the engine speed are detected with respect to the body of the engine body 1. An engine speed sensor 19 for starting the engine and a starter 20 that is driven by the ignition switch 11 (see FIG. 3) and cranks the engine body 1 are provided. The intake passage 2 is provided with a throttle valve 22 that is opened and closed according to the amount of depression of an accelerator pedal (not shown) to throttle air. The intake passage 2 is provided with an intake air temperature sensor (not shown) for detecting the temperature of the air flowing in the intake passage 2, while the exhaust passage 3 is provided with air-fuel ratios in the working chambers E1, E2, E3. An oxygen concentration sensor (so-called λ sensor) 24 for detecting the oxygen concentration is provided.

  Further, as shown in FIG. 2, the direct injection hydrogen injector I1 provided in the rotor housing H1 constituting the engine body 1 is connected via a hydrogen supply pipe 9 to a hydrogen storage tank 13 that stores gaseous hydrogen. . The discharge port of the hydrogen storage tank 13 is provided with a stop valve 14 that is controlled to be opened and closed in order to control hydrogen discharge from the hydrogen storage tank 13 to the hydrogen supply pipe 9. Further, in the hydrogen supply pipe 9, a pressure reducing valve 15 and a first shut-off valve 16 for controlling hydrogen supply to the direct injection hydrogen injector I1 are provided in parallel. The pressure reducing valve 15 is a fuel pressure (hereinafter abbreviated as fuel pressure) of about 0.6 to 0.7 (MPa) for gaseous hydrogen stored in a high pressure state of about 35 (MPa) in the hydrogen storage tank 13. The pressure is reduced to 1 and supplied to the first shut-off valve 16.

  Further, in the hydrogen supply pipe 9, the remaining amount of hydrogen in the hydrogen storage tank 13 is calculated between the first shutoff valve 16 and the direct injection type hydrogen injector I 1, or gaseous hydrogen containing the hydrogen supply pipe 9 is included. A pressure sensor 17 is provided for detecting the residual pressure in the hydrogen supply pipe 9 in order to detect leakage of gaseous hydrogen from the supply system. Note that the gaseous hydrogen supply system in the present invention refers to the hydrogen supply pipe 9, the volume portion 26, which will be described later, the second hydrogen supply pipe 28, the gas passages 4a and 5a in the middle of the direct injection hydrogen injector I1, etc. Assume that each part from the tank 13 to the working chambers E1 to E3 is comprehensively indicated.

  Here, the hydrogen supply pipe 9 is a main passage part that connects the direct injection hydrogen injector I1 and the hydrogen storage tank 13, and at the end of the hydrogen supply pipe 9 opposite to the hydrogen storage tank 13, A second shutoff valve 25 is provided. The hydrogen supply pipe 9 is connected to the volume part 26 via the second cutoff valve 25, and the second cutoff valve 25 can relieve gaseous hydrogen in the hydrogen supply pipe 9 by opening the valve, and the volume part 26 is a tubular member capable of receiving and storing gaseous hydrogen relieved by opening the second shutoff valve 25.

  Further, in the volume portion 26, a third cutoff valve 27 is provided at the end opposite to the second cutoff valve 25. When the third cutoff valve 27 is opened, the volume portion 26 and the intake passage 2 are opened. The throttle valve 22 is connected to the engine body 1 side through the second hydrogen supply pipe 28.

  Here, the second and third shut-off valves 25 and 27 are controlled so as to be closed when gaseous hydrogen is supplied to the direct injection hydrogen injector I1 through the hydrogen supply pipe 9 during engine operation. .

  Although not particularly illustrated, the configuration related to the engine body 1 includes an air cleaner provided in the intake passage 2, an air flow sensor for detecting the intake air amount, a throttle opening sensor for detecting the opening of the throttle valve, an air A surge tank that stabilizes the flow of exhaust gas, an exhaust gas purification catalyst provided in the exhaust passage 3, an exhaust temperature sensor, and the like, and a flow rate of fuel supplied to various injectors provided in the hydrogen supply pipe 9. Other configurations such as a fuel flow meter to be detected are provided.

  Further, as shown in FIG. 3, a control unit 10 is provided for controlling the engine body 1 and the related components as described above. The control unit 10 is a comprehensive control device for the engine main body 1, which is a computer, and includes an intake air amount detected by an air flow sensor, a fuel pressure (residual pressure) in the hydrogen supply pipe 9 detected by a pressure sensor 17. ), The engine water temperature detected by the water temperature sensor 18, the throttle opening sensor, and the throttle opening detected by the idle switch (the switch that is turned on when the accelerator pedal is fully closed, but not shown here), the engine speed sensor The engine speed detected by the engine 19, the exhaust temperature detected by the exhaust gas temperature sensor, the hydrogen flow rate to the direct injection hydrogen injector I 1 detected by the fuel flow meter, and the fact that the passenger has turned on the ignition switch 11. Based on various control information such as key position signal, An ON / OFF command signal and an ignition command signal are output to the injection type hydrogen injector I1 and the spark plug 8 to perform various controls such as fuel injection control and ignition timing adjustment control of the engine body 1, and the first and second cutoffs. These drive control processes are performed by outputting an ON / OFF command signal to the valves 16 and 25 and a PWM command signal to the third shut-off valve 27. The control unit 10 has a microcomputer (not shown) therein, and performs various controls including drive control of the direct injection hydrogen injector I1 and the first to third shut-off valves 16, 25, 27. The microcomputer performs processing such as correction, calculation, and determination that are performed during the execution.

  In addition, the control unit 10 has appropriate storage means (not shown), and the storage means determines whether there is a possibility of water icing, and whether there is a possibility of adhesion of lubricating oil or oil. Various setting data described later, such as temperature threshold value data, fuel pressure threshold value data for determining leakage of gaseous hydrogen from the gaseous hydrogen supply system, and necessary programs are stored.

  The control unit 10 can detect hydrogen leakage from the gaseous hydrogen supply system by comparing it with the fuel pressure threshold value based on the fuel pressure of the hydrogen supply pipe 9 detected by the pressure sensor 17. Note that the fuel pressure threshold value is based on the fuel pressure value that appears due to the residual pressure of gaseous hydrogen even when the gas hydrogen supply system has not leaked and is left for a long time with the first shutoff valve 16 closed after the engine is stopped. Is also set to a small value.

  Next, the structure of the direct injection type hydrogen injector I1 that is driven and controlled by the control unit 10 will be described. 4 and 5 are longitudinal sectional views showing the direct-injection hydrogen injector I1 in the valve-closed state and the valve-opened state, respectively. This hydrogen injector I1 includes an injector body 4 provided with a gas passage 4a extending along the axial direction, and a needle provided with a gas passage 5a provided in the gas passage 4a of the injector body 4 and also extending along the axial direction. And a valve 5.

  The injector body 4 communicates with the hydrogen supply pipe 9 (see FIG. 2) at one end side (the upper end side in FIGS. 4 and 5), and the injection hole 4b at the other end side (the lower end side in FIGS. 4 and 5). The engine body 1 faces the working chamber E1. The movable portion 5b of the needle valve 5 provided in the gas passage 4a is held so as to slide along the inner peripheral surface of the gas passage 4a on one end side (the upper end side in FIGS. 4 and 5). On the other hand, the seal portion 5c is configured on the other end side (the lower end side in FIGS. 4 and 5), and is branched from the gas passage 5a to the upstream side of the seal portion 5c so as to open on the side surface of the needle valve 5. A plurality of formed branch passages 5d are provided. Corresponding to the seal portion 5c of the needle valve 5, a valve seat surface 4c is formed in the gas passage 4a of the injector body 4 on the upstream side of the injection hole 4b. Since the seal portion 5c of the needle valve 5 is seated on the valve seat surface 4c, hydrogen injection from the injection hole 4b of the injector main body 4 is prevented, and hydrogen from the direct injection type hydrogen injector I1 into the working chamber E1 of the engine main body 1 is prevented. Supply is stopped.

  When the fuel to be used is a gaseous fuel such as gaseous hydrogen as in the present embodiment, a large direct injection hydrogen injector I1 is used so that the amount of fuel injected is increased. The seal portion 5c of such a large direct injection hydrogen injector I1 is made of a rubber material member in order to improve the airtightness of the injection hole 4b when the valve is closed.

  In addition, a magnetic body (not shown) is attached to the needle valve 5, while a solenoid coil 6 that constitutes the electromagnetic valve V <b> 1 together with the needle valve 5 is incorporated in the injector body 4 around the gas passage 4 a. .

  In the needle valve 5, the gas passage 5 a is a member fixed to a predetermined position by being attached to the injector body 4, while the movable portion 5 b can be shifted in the vertical direction along the gas passage 4 a. It is an important member.

  A coil spring 7 is provided between the gas passage 5a and the movable portion 5b so as to be sandwiched between them, and one end of the coil spring 7 is in contact with the end of the gas passage 5a. Thereby, the movable part 5b is always pressed downward.

  With this configuration, in the direct injection hydrogen injector I1, when the drive current is supplied to the solenoid coil 6, the movable portion 5b resists the elastic force of the coil spring 7 as shown in FIG. Shifted upward along the gas passage 4a. Within the moving range of the movable portion 5b, the amount of shift upward of the movable portion 5b increases as the drive current increases. Here, as described above, when the direct injection hydrogen injector I1 is large, a large current is required as a drive current necessary for valve opening.

  That is, in a state where the drive current is not supplied to the solenoid coil 6, the movable portion 5 b is pressed downward by the elastic force of the coil spring 7, and the seal portion 5 c is a valve formed in the gas passage 4 a of the injector body 4. By seating on the seat surface 4c, the solenoid valve V1 is closed (see FIG. 3), and on the other hand, in a state where the drive current is supplied to the solenoid coil 6, the seal portion 5c is resisted against the elastic force of the coil spring 7. The electromagnetic valve V1 opens by separating from the valve seat surface 4c (see FIG. 4). In the state where the electromagnetic valve V1 is opened, as indicated by the broken arrow in FIG. 4, the gaseous hydrogen flows into the gas passage 4a of the injector body 4, the gas passage 5a of the needle valve 5, the branch passage 5d of the needle valve 5, and the injector. The gas flows in the order of the gas passage 4 a of the main body 4 and the injection hole 4 b of the injector main body 4, and is injected from the injection hole 4 b of the injector main body 4.

  The injection timing and the injection amount of gaseous hydrogen in the direct injection hydrogen injector I1 having such a configuration are controlled by a control unit 10 including a microcomputer. More specifically, the control unit 10 is based on signals detected from various sensors such as an air flow meter, a throttle sensor, a pressure sensor 17, a water temperature sensor 18, and an engine speed sensor 19 in accordance with a program stored in the storage unit. The pulse timing of the ON / OFF command signal output to the direct injection hydrogen injector I1, that is, the valve opening timing and valve opening time of the electromagnetic valve V1, is calculated to control the injection timing and injection amount of gaseous hydrogen.

  By the way, in an engine equipped with a conventional direct injection type gaseous fuel injector, moisture, mist-like oil, lubricating oil, etc. adhere to the injector, and these are frozen and fixed due to a decrease in the outside air temperature. There was a possibility of hindering the opening of the injector. Therefore, there is a method that makes it easy to open the direct-injection gaseous fuel injector by reducing the fuel pressure of the gaseous fuel supply system when the engine is stopped. However, this method uses a pressure sensor or the like to detect fuel leakage. When the above-described method is employed, there is a possibility that the state in which the fuel pressure is reduced by the method is erroneously determined as a state in which fuel leakage has occurred.

  In contrast, in the present embodiment, at the time of starting the engine, the control unit 10 detects hydrogen leakage in the gaseous hydrogen supply system, and then reduces the fuel pressure applied to the direct injection hydrogen injector I1, thereby opening the direct injection hydrogen injector I1. It was made possible to suppress erroneous detection of hydrogen leakage by the control unit 10 while facilitating the valve operation.

  Hereinafter, the drive control of the direct injection hydrogen injector I1 and the first to third shutoff valves 16, 25, 27 executed by the control unit 10 will be described with reference to the time chart of FIG. 6 and the flowchart of FIG. During operation of the engine, the first cutoff valve 16 is opened to supply gaseous hydrogen from the hydrogen storage tank 13 to the direct injection hydrogen injector I1, while the second and third cutoff valves 25, The valve 27 is closed as described above.

  When the passenger shifts the key position of an ignition key (not shown) to the “OFF” position, the control unit 10 outputs an engine stop command signal based on the key position signal of the ignition switch 11 (FIG. 7). Step s1). At this time, the first shutoff valve 16 and the direct injection type hydrogen injector I1 are closed by an OFF command signal from the control unit 10, and the injection of gaseous hydrogen into the working chambers E1 to E3 is stopped, thereby rotating the engine. The number gradually decreases as shown in FIG. 6 and the engine is stopped (time t1 in FIG. 6, step s2 in FIG. 7).

  When the occupant shifts the key position of the ignition key to the “ON” position from the engine stop state, the control unit 10 determines that an engine restart request has occurred based on the key position signal of the ignition switch 11 (FIG. 7 s3), the detection signal output by each component shown in FIG. 2 is read. Among these, based on the fuel pressure detected by the pressure sensor 17, the control unit 10 detects the presence or absence of leakage of gaseous hydrogen from the gaseous hydrogen supply system including the hydrogen supply pipe 9 (step s4 in FIG. 7).

  Here, if there is no leakage of gaseous hydrogen in the gaseous hydrogen supply system, the closed state of the first shutoff valve 16 is maintained, so that the fuel pressure reduced by the pressure reducing valve 15 (approximately 0.6 to 0.7). The value of (MPa) is detected. In the control unit 10, the fuel pressure threshold is set to 0.4 (MPa), for example, and when the control unit 10 determines that the detected fuel pressure value is 0.4 (MPa) or more (step s4: YES) ) Based on the signal detected by the water temperature sensor 18, it is assumed that there is no possibility of leakage of gaseous hydrogen. It is determined whether or not (step s5).

  Here, in the control unit 10, the temperature threshold is set to 0 ° C., for example, and when the control unit 10 determines that the engine water temperature is 0 ° C. or less (step s5: YES), it is a cold time. In addition, it is determined that there is a possibility of water icing in the direct-injection hydrogen injector I1 and a possibility of oil and lubricating oil sticking. Note that the temperature of the direct injection hydrogen injector I1 can be considered to fluctuate substantially in relation to the engine water temperature of the engine body 1, and the control unit 10 determines that the direct injection hydrogen injector is based on the signal detected by the water temperature sensor 18. The temperature of I1 can be indirectly determined.

  If it is determined in step s5 that there is a possibility of water icing in the direct-injection hydrogen injector I1 or the possibility of oil or lubricating oil sticking, the control unit 10 outputs an ON command signal to output the second cutoff valve. 25 is opened, and gaseous hydrogen in the hydrogen supply pipe 9 is relieved. Since the released gaseous hydrogen is stored in the volume portion 26, the volume of the gaseous hydrogen supply system capable of storing the gaseous hydrogen remaining in the hydrogen supply pipe 9 is increased, and the fuel pressure is reduced (see FIG. 6 at time t2, step s6 in FIG. Thereby, for example, the fuel pressure of about 0.6 to 0.7 (MPa) is corrected to about 0.5 (MPa), and the action of gaseous hydrogen for closing the direct injection hydrogen injector I1 is reduced. Even at this time, the first and third shutoff valves 16 and 27 are still in the closed state.

  After a predetermined time, the control unit 10 outputs an OFF command signal to the second shutoff valve 25 to close it (time t3 in FIG. 6, step s7 in FIG. 7), and direct injection hydrogen injector I1 and starter 20 An ON command signal is output for each of them, and cranking is started (time t3 in FIG. 6, step s8 in FIG. 7). As a result, the engine is started, and the engine speed gradually increases as shown in FIG. At this time, since the first shut-off valve 16 is in a closed state, when the engine is started, gaseous hydrogen remaining in the gaseous hydrogen supply system after the engine is stopped is used.

  As described above, when the direct injection type hydrogen injector I1 cannot be opened due to freezing of water, sticking of oil or lubricating oil, the movable part 5b (see FIG. 4) is moved downward by reducing the fuel pressure when starting the engine. Since the action of gaseous hydrogen that presses and closes the direct injection hydrogen injector I1 is reduced, the direct injection hydrogen injector I1 can be easily opened. In the present embodiment, an ON command signal is output to the direct injection hydrogen injector I1 in a state where the pressure is reduced to a fuel pressure (about 0.5 (MPa) as a specified value) at which the movable part 5b is easily shifted. Thus, the signal output timing is controlled.

  Furthermore, since the fuel pressure of gaseous hydrogen is reduced after the detection of gaseous hydrogen leakage by the control unit 10, the erroneous detection of gaseous hydrogen leakage by the control unit 10 can be suppressed.

  Moreover, since the 1st cutoff valve 16 is a valve closing state at the time of the detection of gaseous hydrogen leak, the inside of the hydrogen supply pipe | tube 9 is prevented from becoming high pressure. As a result, the direct-injection hydrogen injector I1 is easy to open, and if a gaseous hydrogen leak has occurred from the gaseous hydrogen supply system, the control unit 10 is controlled by the high-pressure gaseous hydrogen supplied from the hydrogen storage tank 13. It is possible to reliably prevent erroneous detection such as overlooking the occurrence of gaseous hydrogen leakage.

  Further, the control unit 10 determines whether or not it is cold by determining whether or not the engine water temperature is 0 ° C. or less in step s5, and the possibility of water icing, oil, lubrication, etc. Although the possibility of oil sticking is determined, it is possible to ensure the operation of the direct injection type hydrogen injector I1 during the cold state.

  The effect of determining whether or not the control unit 10 is cold is significant when gaseous fuel is used as fuel as in this embodiment. That is, for the reasons described above, a large current is required as a drive current necessary for opening the valve, and since a rubber material is used for the seal portion 5c, moisture easily adheres to the seal portion 5c and freezes. Therefore, although the movable part 5b tends to be more difficult to open, the direct-injection hydrogen injector I1 is further reduced by reducing the fuel pressure of gaseous hydrogen when it is determined that it is cold as in this embodiment. The valve can be opened reliably.

  Oil and lubricating oil have a lower freezing point than moisture and tend to solidify when the outside air temperature is minus tens of degrees Celsius. Therefore, the main factor that hinders the opening of the direct injection hydrogen injector I1 is oil and lubricating oil. If there is, the temperature threshold value may be set low.

  For the reasons described above, the direct injection hydrogen injector I1 that injects gaseous hydrogen requires a large current as a drive current necessary for opening the valve. Therefore, when the power of the battery power supply is insufficient for some reason. There is a possibility that the movable part 5b is difficult to open. In the present embodiment, the control unit 10 determines whether or not it is cold at step s5, but the valve can be opened more reliably even if the direct injection hydrogen injector I1 is large. The determination process of step s5 for determining whether or not it is cold may be omitted, and step s6 for decreasing the fuel pressure may be executed. In addition, a detection unit that detects the remaining power of the battery power source may be provided, and the control unit 10 may determine whether or not the fuel pressure needs to be reduced based on the detection result of the detection unit.

  In addition, after the leakage of gaseous hydrogen is detected by the pressure sensor 17, the gaseous hydrogen in the hydrogen supply pipe 9 is relieved by the second shutoff valve 25, and the relieved gaseous hydrogen is stored in the volume portion 26 to increase the volume. By increasing, the fuel pressure acting on the direct injection hydrogen injector I1 can be easily reduced. Further, as in the present embodiment, by storing the gaseous hydrogen relieved by the second shut-off valve 25 in the volume portion 26, the fuel pressure is easily reduced only by the valve opening control of the second shut-off valve 25. be able to.

  In step s8, when an ON command signal is output to the direct injection hydrogen injector I1 and cranking is started, the control unit 10 outputs an ON command signal and opens the first shutoff valve 16. As a result, the supply of gaseous hydrogen from the hydrogen storage tank 13 is resumed (time t4 in FIG. 6, step s9 in FIG. 7), so that the engine can be completely exploded.

  By the way, the gaseous hydrogen that has flowed into the volume portion 26 when the second shut-off valve 25 is opened is sealed in the volume portion 26 when the second shut-off valve 25 is closed again. In this embodiment, this is discharged into the working chambers E1 to E3 so that gaseous hydrogen can be effectively utilized. In order to execute this, the control unit 10 opens the third shutoff valve 27 of the volume portion 26 after the engine is completely exploded, and makes the volume portion 26 and the intake passage 2 communicate with each other. Is released to the intake passage 2 side (time t5 in FIG. 6, step s10 in FIG. 7). The released gaseous hydrogen is finally supplied into the working chambers E1 to E3 of the engine body 1 together with the intake air.

  Here, the injection amount of gaseous hydrogen injected from the direct injection hydrogen injector I1 is controlled to a predetermined amount by the control unit 10 in order to maintain the air-fuel ratio in the working chambers E1 to E3 at a predetermined value. However, as described above, surplus gaseous hydrogen is supplied from the intake passage 2, which may cause a deviation in the air-fuel ratio. Therefore, as shown in FIG. 3, the control unit 10 outputs a PWM signal to the third shut-off valve 27, and affects the air-fuel ratio by appropriately adjusting the duty ratio in the PWM signal. It is possible to release gaseous hydrogen at a predetermined flow rate that does not affect the flow rate.

  When releasing gaseous hydrogen from the volume part 26, it is preferable to discharge | emit little by little over a long time so that the air fuel ratio of the working chambers E1-E3 may not be affected as mentioned above. Therefore, in the present embodiment, the time for opening the third shut-off valve 27 is set in advance in the control unit 10, and this time can be counted by appropriate timer means (not shown). When the count value reaches a predetermined time (time t6-t5) or more, the third shut-off valve is closed (time t6 in FIG. 6, step s11 in FIG. 7), and the process is returned.

  By the way, when the control unit 10 determines in step s5 that the water temperature is not lower than 0 ° C., that is, higher than 0 ° C. (step s5: NO), the possibility of freezing of water in the direct injection hydrogen injector I1, First, an ON command signal is output to the first shutoff valve 16 and supply of gaseous hydrogen is started (step s12 in FIG. 7). Then, the control unit 10 outputs an ON command signal to each of the direct injection hydrogen injector I1 and the starter 20, starts cranking (step s8 in FIG. 7), and returns the process.

  If the fuel pressure detected by the pressure sensor 17 is below the threshold value in step s4 (step s4: NO in FIG. 7), the control unit 10 indicates that gaseous hydrogen leakage has occurred in the gaseous hydrogen supply system. Judgment is made and a signal for prohibiting engine start is output (step s14 in FIG. 7). At this time, the control unit 10 informs the occupant of the occurrence of leakage by an appropriate method such as transmission of a warning sound or lighting display of a warning lamp (step s15 in FIG. 7), and returns the process.

  Incidentally, in the above-described embodiment, gaseous hydrogen is relieved by opening the second shut-off valve 25 and stored in the volume portion 26, thereby increasing the volume of the gaseous hydrogen supply system and reducing the fuel pressure. However, it is not necessarily limited to this. FIG. 8 is a diagram conceptually showing an engine body 1 and a configuration related thereto according to another embodiment of the present invention. For example, as shown in FIG. 8, the fuel pressure of gaseous hydrogen can also be reduced by providing a piston 55 that can advance and retreat in the longitudinal direction at the end of the gaseous hydrogen supply pipe 39. Specifically, an ON / OFF command signal can be output from the control unit 40 to an actuator (not shown) of the piston 55, and the piston 55 is driven from the position of the solid line to the position of the two-dot chain line. The volume of the supply system can be increased.

  During engine operation, the piston 55 is in a position indicated by a solid line, and the gas hydrogen supply pipe 39 has a pressure reducing valve 45, a shut-off valve 46, and a pressure sensor 47 between the piston 55 and the hydrogen storage tank 13 located at the solid line. Is provided. Therefore, the space between the hydrogen storage tank 13 and the piston 55 corresponds to the main passage portion of the first embodiment described above.

  When supply of gaseous hydrogen from the hydrogen storage tank 13 is started after detection of leakage of gaseous hydrogen by the control unit 40, the control unit 40 operates the working chambers E1 to E3 based on the detection result of the oxygen concentration sensor 24 and the like. Drive control is performed so that the piston 55 is gradually returned to the position indicated by the solid line so that the air-fuel ratio in the inside does not change significantly. Accordingly, the volume of the gaseous hydrogen supply system can be increased with a simple configuration without providing a plurality of shutoff valves, and the gaseous hydrogen stored in the hydrogen supply pipe 39 can be effectively utilized. Here, about each component shown in FIG. 8, the same code | symbol is attached | subjected about the thing similar to the first embodiment mentioned above, and the description is abbreviate | omitted.

  In each of the above-described embodiments, the engine body 1 is a rotary type engine. However, the present invention is not limited to this, and the present invention can also be applied to a reciprocating engine.

  Further, in each of the above-described embodiments, an engine using gaseous hydrogen is described. However, a gaseous fuel such as compressed natural gas or liquefied petroleum gas may be used as long as the gaseous fuel is directly injected into the working chamber of the engine body. It may be an engine using.

In correspondence between the configuration of the present invention and the above-described embodiment,
The in-cylinder fuel injection valve of the present invention corresponds to the gaseous hydrogen injection valve I1,
Similarly,
The gaseous fuel tank corresponds to the hydrogen storage tank 13,
The gaseous fuel supply passage corresponds to the gaseous hydrogen supply pipes 9, 39,
The fuel pressure detection means corresponds to the pressure sensors 17, 47,
The leak detection means corresponds to the control unit 10 that executes step s4,
The fuel pressure correction means corresponds to the second cutoff valve 25, the volume portion 26, the control unit 10 that executes step s6, or the piston 55, the control unit 40,
The temperature detection means corresponds to the water temperature sensor 18,
The shut-off valve corresponds to the second shut-off valve 25,
The second gaseous hydrogen supply passage corresponds to the second hydrogen supply pipe 28,
The purge valve corresponds to the third shut-off valve 27,
The purge valve control means corresponds to the control unit 10 that executes steps s10 and s11.
The present invention is not limited only to the configuration of the above-described embodiment, and many embodiments can be obtained.

The figure which represents schematically the rotary type engine main body which concerns on embodiment of this invention. The figure which represents notionally the engine main body which concerns on embodiment of this invention, and the structure relevant to it. FIG. 3 is a block diagram illustrating a control system for controlling each configuration illustrated in FIG. 2. The longitudinal cross-sectional view which shows the direct injection type hydrogen injector in a closed state. The longitudinal cross-sectional view which shows the direct injection type hydrogen injector in an open state. The time chart which shows the drive control process of the direct injection type hydrogen injector and the 1st-3rd cutoff valve which are performed by the control unit which concerns on embodiment of this invention. The flowchart which shows the drive control processing of the direct injection type hydrogen injector and the 1st-3rd cutoff valve which are performed by the control unit which concerns on embodiment of this invention. The figure which represents notionally the engine main body which concerns on another embodiment of this invention, and the structure relevant to it.

Explanation of symbols

9, 39 ... Hydrogen supply pipes 10, 40 ... Control unit 13 ... Hydrogen storage tank 16 ... First shutoff valve 17, 47 ... Pressure sensor 18 ... Water temperature sensor 25 ... Second shutoff valve 26 ... Volume 27 ... Third shutoff valve 28 ... Second gaseous hydrogen supply pipe 55 ... Piston I1 ... Gas hydrogen injection valve

Claims (5)

An in-cylinder fuel injection valve that directly injects gaseous fuel into the cylinder;
A gaseous fuel tank;
A gaseous fuel supply passage,
An engine fuel injection device for connecting the gaseous fuel tank and the in-cylinder fuel injection valve by the gaseous fuel supply passage,
Fuel pressure detection means disposed in the gaseous fuel supply passage;
Leakage detecting means for detecting fuel leakage from the gaseous fuel supply system including the gaseous fuel supply passage based on the fuel pressure detected at the time of engine start;
A fuel injection device for an engine, comprising fuel pressure correction means for reducing the fuel pressure after the fuel leakage is detected by the leakage detection means when the engine is started. Temperature detecting means for detecting a temperature related to the in-cylinder fuel injection valve;
The engine fuel injection device according to claim 1, wherein the fuel pressure correcting means is operated when the temperature is equal to or lower than a predetermined temperature. 3. The fuel injection device for an engine according to claim 1, wherein the fuel pressure correction means decreases the fuel pressure by increasing a volume of a gaseous fuel supply system capable of storing gaseous fuel when the engine is started. A shutoff valve capable of relieving the gaseous fuel in the gaseous fuel supply passage;
A volume portion capable of storing the gaseous fuel relieved from the shut-off valve,
4. The fuel injection device for an engine according to claim 3, wherein the fuel pressure correcting means opens the shut-off valve when the engine is started, and reduces the fuel pressure by storing the gaseous fuel in the volume portion. A second gaseous fuel supply passage connecting the volume and the intake passage;
A purge valve is disposed in the second gaseous fuel supply passage;
The engine fuel injection device according to claim 4, further comprising a purge valve control unit that opens the purge valve to discharge the stored gaseous fuel to the intake passage.

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