JP2007278144A - Fuel injection device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection device for an engine capable of opening a cylinder injection valve while securing stable engine startability irrespective of freezing of moisture, intrusion of lubricating oil or the like. <P>SOLUTION: This device is provided with a throttle valve 22 correcting cylinder pressure of a working chamber E1 and a pressure sensor 17 detecting hydrogen pressure supplied to a direct injection type hydrogen injector I1. A control unit 10 opens the throttle valve 22 to correct cylinder pressure of the working chamber at time of start and controls the throttle valve 22 to reduce increase correction quantity as compared to that when hydrogen pressure is high, when hydrogen pressure is low at a time of start. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine fuel injection device including an in-cylinder injection valve that directly injects fuel into a working chamber.

  Conventionally, an engine having a direct injection type in-cylinder injection valve that directly injects fuel into a working chamber is known, and examples include engines that use gaseous fuel such as compressed natural gas, liquefied petroleum gas, and compressed hydrogen. . In an engine using such a gaseous fuel, the moisture generated by the combustion or the moisture originally contained in the gas freezes as the outside air temperature decreases, and it adheres to the injection valve that injects the gaseous fuel, and the opening operation is performed. The problem of obstructing can occur.

  In addition, in a hydrogen engine that uses compressed hydrogen as a gaseous fuel, in addition to the above-described factors, if the engine is started with moisture adhering to the vicinity of the hydrogen injection hole, adiabatic expansion of hydrogen accompanying hydrogen injection There is a possibility that water adhering to the vicinity of the injection hole may freeze due to rapid cooling.

  In order to deal with such a problem, for example, Patent Document 1 proposes a method of setting a long drive current supply time to the injection valve at a low temperature start and melting icing by a heat generation action associated therewith.

JP-A-11-264334

  However, as disclosed in Patent Document 1, when the energization time is lengthened, the fuel injection amount increases as a result, and the air-fuel ratio at the time of starting becomes over-rich. May occur. Therefore, it is highly desirable that the opening operation of the injection valve is reliably executed while ensuring a stable engine startability.

  Further, there is a problem that the lubricating oil enters the in-cylinder injection valve and prevents the operation of the in-cylinder injection valve. In particular, a so-called rotary that includes a rotor housing having a trochoidal inner peripheral surface and a planar side housing, and in which a plurality of working chambers are defined by housing the rotor in an internal space formed therein. In an engine of a type, when lubricating oil is supplied to the inner peripheral surface of a rotor housing in order to rotate a rotor smoothly, it becomes a big problem.

  As described above, when the lubricating oil enters the in-cylinder injection valve, there is a problem that the operation of the injection valve is hindered due to the inherent viscosity of the lubricating oil, as in the case of icing of moisture described above.

  An object of the present invention is to provide a fuel injection device capable of opening a cylinder injection valve while ensuring stable engine startability regardless of moisture icing, intrusion of lubricating oil, or the like. To do.

  An engine fuel injection device according to the present invention is an engine fuel injection device including an in-cylinder injection valve that directly injects fuel into a working chamber, the in-cylinder pressure correcting means for correcting the in-cylinder pressure in the working chamber, Fuel pressure detecting means for detecting the fuel pressure supplied to the in-cylinder injection valve, and the in-cylinder pressure correcting means corrects the in-cylinder pressure of the working chamber to be increased at the start, and when the fuel pressure at the start is low The increase correction amount of the in-cylinder pressure is reduced when the temperature is high.

  According to this configuration, the in-cylinder pressure in the working chamber is increased and corrected at the start by the in-cylinder pressure correcting means, so that the in-cylinder injection valve is pressed in the opening direction by the in-cylinder pressure in the working chamber. Therefore, the cylinder pressure in the working chamber, which has been corrected for correction, can assist the opening operation of the cylinder injection valve, so that stable engine startability can be achieved regardless of moisture icing or ingress of lubricating oil. The in-cylinder injection valve can be opened while ensuring.

  Further, as described above, increasing the in-cylinder pressure of the working chamber results in a rapid increase in the engine speed, and if the degree of increase is large, the occupant may feel uncomfortable. According to this configuration, when the fuel pressure at the time of starting is low, the in-cylinder pressure of the working chamber is controlled so as to reduce the increase correction amount with respect to when the fuel pressure is high. Since the increase amount of the engine is kept low, it is possible to prevent a sudden increase in the engine speed and to make the passenger feel uncomfortable.

  Further, when the fuel pressure is low, the increase in the cylinder pressure in the working chamber is kept low, thereby reducing the differential pressure between the cylinder pressure in the working chamber and the fuel pressure supplied to the cylinder injection valve. Therefore, it is possible to avoid a situation in which it is difficult to supply fuel into the working chamber due to the cylinder pressure in the working chamber that has been corrected for increase.

  In one embodiment of the present invention, the in-cylinder pressure correcting means includes an in-cylinder pressure increase correction in which a relationship between a fuel pressure detected by the fuel pressure detecting means and an increase correction amount of the in-cylinder pressure in the working chamber is set in advance. The increase correction amount is determined based on an amount determination map.

  According to this configuration, an accurate in-cylinder pressure increase correction amount can be determined based on the fuel pressure value detected by the fuel pressure detecting means. Accordingly, it is possible to avoid a situation where the increase correction amount is too large and the engine speed is increased unnecessarily, or the increase correction amount is too small and the opening operation of the in-cylinder injection valve fails.

  In one embodiment of the present invention, a temperature detecting means for detecting a temperature related to the in-cylinder injection valve is provided, and the in-cylinder pressure correcting means is configured so that when the temperature at the start is less than a predetermined temperature, In-cylinder pressure is increased and corrected.

  According to this configuration, even if icing has occurred, the in-cylinder injection valve can be forcibly opened.

  In one embodiment of the present invention, an injection valve operating state detecting means for detecting an operating state of the in-cylinder injection valve is provided, and when the opening operation of the in-cylinder injection valve is not detected at the start, the in-cylinder pressure correcting means is provided. It is operated.

  According to this configuration, by detecting the operating state of the in-cylinder injection valve, it is possible to surely avoid a situation in which the in-cylinder pressure in the working chamber is unnecessarily increased and correct the uncomfortable feeling given to the passenger as much as possible. .

  In one embodiment of the present invention, the injection valve operating state detecting means detects an operating state of the in-cylinder injection valve based on a cranking time.

  According to this configuration, it is possible to easily detect whether or not the in-cylinder injection valve is opened only by counting the cranking time.

  In one embodiment of the present invention, the in-cylinder injection valve is controlled to be opened and closed by supplying a driving current, and the injection valve operating state detecting means determines the operating state of the in-cylinder injection valve as the driving current. It detects based on.

  According to this configuration, the opening operation of the in-cylinder injection valve can be detected easily and reliably only by detecting the change in the drive current.

  In one embodiment of the present invention, the in-cylinder pressure correcting means is constituted by an air amount adjusting means for adjusting an air amount supplied to the engine.

  According to this configuration, it is possible to increase and correct the in-cylinder pressure of the working chamber using an existing configuration without providing any new means.

  According to the present invention, since the in-cylinder pressure of the working chamber is increased and corrected by the in-cylinder pressure correction means at the time of start-up, the opening operation of the in-cylinder injection valve can be assisted. Regardless of the intrusion or the like, the in-cylinder injection valve can be opened while ensuring a stable engine startability.

  Further, the in-cylinder pressure correction means controls the in-cylinder pressure of the working chamber so as to reduce the increase correction amount with respect to the high time when the fuel pressure at the time of starting is low. The amount of increase in the in-cylinder pressure can be kept low. Therefore, it is possible to avoid a situation in which a rapid increase in the engine speed is suppressed and the passenger feels uncomfortable.

  Further, when the fuel pressure is low, the increase in the cylinder pressure in the working chamber is kept low, thereby reducing the differential pressure between the cylinder pressure in the working chamber and the fuel pressure supplied to the cylinder injection valve. Therefore, it is possible to avoid a situation in which it is difficult to supply fuel into the working chamber due to the cylinder pressure in the working chamber that has been corrected for increase.

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, E2, E3 are defined. Each working chamber E1, E2, E3 repeats expansion and contraction with the rotation of the rotor R around the eccentric axis C, and the intake stroke in each working chamber E1, E2, E3 during one rotation of the rotor R. A series of strokes consisting of a compression stroke, an expansion stroke, and an exhaust stroke is completed.

  The rotor housing H1 was supplied into the working chambers E1, E2, and E3, a gaseous hydrogen injection valve I1 that directly injects gaseous hydrogen into the working chambers E1, E2, and E3 (hereinafter referred to as a direct injection type hydrogen injector I1) and the working chambers E1, E2, and E3. There is provided a spark plug 8 for igniting an air-fuel mixture comprising fuel (gaseous hydrogen or gasoline) and 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.

  Further, in this embodiment, in addition to the direct injection type hydrogen injector I1 provided in the rotor housing H1, a gasoline injection valve I2 (hereinafter referred to as a port injection type gasoline injector) that is attached to the intake passage 2 and injects gasoline into the intake passage 2. A gas hydrogen injection valve I3 (hereinafter referred to as a port injection type hydrogen injector I3) that is similarly attached to the intake passage 2 and injects gaseous hydrogen into the intake passage 2 is provided upstream thereof. Is provided. When it is necessary to supply fuel into the working chamber of the engine body 1, it can be directly adjusted according to various states such as the engine speed, the remaining amount of hydrogen or gasoline, or according to the demand of the passenger. An appropriate one is selected from among the injection type hydrogen injector I1, the port injection type gasoline injector I2, and the port injection type hydrogen injector I3.

  FIG. 2 is a control system diagram conceptually showing the engine body 1 and the configuration related thereto. The direct injection type hydrogen injector I1, the port injection type gasoline injector I2, and the port injection type hydrogen injector I3 are provided with solenoid valves V1, V2, and V3, respectively. The fuel injection in each of the injectors I1, I2, and I3 is performed by each solenoid valve. Control is performed based on the opening / closing operations of V1, V2, and V3. In FIG. 2, the solenoid valves V1, V2, and V3 are shown as being provided separately for the injectors I1, I2, and I3. In practice, however, the cross-sectional structure of the direct injection hydrogen injector I1 is shown. As shown in FIG. 3 and FIG. 4, solenoid valves V1, V2, and V3 are incorporated in the injectors I1, I2, and I3.

  Further, as shown in FIG. 2, in the present embodiment, with respect to the main body of the engine body 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 and a starter 20 that is driven by an ignition switch (not shown) and cranks the engine body 1 are provided. The intake passage 2 has an idle speed control function for correcting the amount of air supplied from the actuator 21 to the working chamber E1 so that the idle speed coincides with the target rotational speed when idling, and when not idling. , A function of increasing and correcting the amount of air supplied to the working chamber E1 in accordance with the amount of depression of an accelerator pedal (not shown) or the output of a drive signal of the control unit 10 during drive control of a direct injection hydrogen injector I1 described later. Are provided with a throttle valve 22. The intake passage 2 is provided with an intake air temperature sensor 23 that detects the temperature of the air flowing in the intake passage 2, while the exhaust passage 3 calculates the air-fuel ratio in the working chambers E 1, E 2, E 3. Accordingly, 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 I 1 provided in the rotor housing H 1 constituting the engine body 1 and the port injection hydrogen injector I 3 attached to the intake passage 2 are connected via a hydrogen supply pipe 9. And connected to a hydrogen storage tank 14 for storing gaseous hydrogen. On the other hand, the port injection gasoline injector I2 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, a shutoff valve 16 is provided in the hydrogen supply pipe 9 for controlling hydrogen supply to each of the direct injection type hydrogen injector I1 and the port injection type hydrogen injector I3. Further, in the hydrogen supply pipe 9, the residual pressure in the hydrogen supply pipe 9 is detected between the shutoff valve 16 and the direct injection hydrogen injector I 1 in order to calculate the remaining amount of hydrogen in the hydrogen storage tank 14. A pressure sensor 17 is provided.

  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 22, A surge tank that stabilizes the air flow, an exhaust gas purification catalyst provided in the exhaust passage 3, an exhaust temperature sensor, etc., and a hydrogen supply pipe 9 or a gasoline supply pipe 13 that are supplied to various injectors. A configuration other than the above is provided, such as a fuel flow meter for detecting the flow rate of the fuel to be discharged.

  Further, as shown in FIG. 2, a control unit 10 is provided for controlling the engine body 1 and related components as described above. The control unit 10 is a comprehensive control device for the engine main body 1 composed of a computer, and an operation signal from a selection switch (not shown) for selecting a hydrogen engine drive mode or a gasoline engine drive mode by a passenger. , The amount of intake air detected by the air flow sensor, the residual pressure in the hydrogen supply pipe 9 detected by the pressure sensor 17, the engine water temperature detected by the water temperature sensor 18, the throttle opening sensor and the idle switch (when the accelerator pedal is fully closed) The switch that is turned on (not shown here), the throttle opening detected by the engine, the engine speed detected by the engine speed sensor 19, the exhaust temperature detected by the exhaust temperature sensor, and the fuel flow meter. Based on various control information such as fuel flow rate to the injector There are, performs various controls such as fuel injection control and ignition timing adjustment control of the engine 1, and performs a drive control process of the injector I1, I2, I3, which will be described later. The control unit 10 has a microcomputer (not shown) in its interior, and performs correction calculations, determinations, and the like executed when performing various controls including drive control of the injectors I1, I2, and I3. Processing is performed by the microcomputer. Further, the control unit 10 has a timer means 25 therein, and counts the starter 20 operating time by the operation of the starter 20 of the occupant.

  The control unit 10 also has appropriate storage means (not shown). The storage means includes temperature threshold value data for determining the possibility of freezing, and opening operation of the direct injection hydrogen injector I1. Are stored, such as starter operating time threshold value data, in-cylinder pressure increase correction amount determination map, start determination rotation speed data of the engine body 1, and other various setting data described below and necessary programs.

  Next, the structure of the direct injection type hydrogen injector I1 that is driven and controlled by the control unit 10 will be described. 3 and 4 are longitudinal sectional views showing the direct injection hydrogen injector I1 in the closed state and the open 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. 3 and 4), and the injection hole 4b at the other end side (the lower end side in FIGS. 3 and 4). 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. 3 and 4). On the other hand, the seal portion 5c is configured on the other end side (the lower end side in FIGS. 3 and 4), 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 body 4 is hindered, and hydrogen supply from the direct injection type hydrogen injector I1 into the working chamber of the engine body 1 is prevented. Stopped.

  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 such a 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. It is shifted upward along the gas passage 4c. 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.

  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 timing of the pulse output to the direct injection hydrogen injector I1 and its pulse width, that is, the opening operation timing and the opening time of the electromagnetic valve V1, are calculated, and the injection timing and injection amount of gaseous hydrogen are stored in the storage means. Control according to the stored program.

  Here, the direct injection type hydrogen injector I1 provided in the rotor housing H1 has been described. However, in this embodiment, the port injection type hydrogen injector I3 attached to the intake passage 2 has the same configuration. It is used.

  In the engine body 1, hydrogen injectors (direct injection type hydrogen injector I 1 and port injection type hydrogen injector I 3) having the above-described structure are selectively used according to the engine speed detected by the engine speed sensor 19. The injection timing is changed. Here, the control for selectively using the hydrogen injector will be specifically described. FIG. 5 is an explanatory diagram showing a hydrogen injector employed according to each engine speed and the injection timing thereof. First, in the low rotation region (about 800 to 2500 rpm), the direct injection type hydrogen injector I1 is employed, and injection in the compression stroke is executed. Here, if 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, and compression after the intake stroke is completed. Gaseous hydrogen is supplied during the stroke, and a decrease in fuel charging efficiency is suppressed.

  Further, in the middle rotation region (about 2500 to 5000 rpm), the direct injection hydrogen injector I1 is employed, and injection in the intake stroke is executed. 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 I1 at an early stage of the intake stroke, and the mixing time is increased. By ensuring, the mixing property of gaseous hydrogen and air is improved.

  Finally, in the high rotation region (about 5000 to 7000 rpm), the direct injection type hydrogen injector I1 and the port injection type hydrogen injector I3 are used together. Here, the port injection type hydrogen injector I3 is used in order to improve the mixing property of gaseous hydrogen and air, and the direct injection type hydrogen injector I1 is used in order to suppress the torque reduction at the same time as the premix injection is executed. The injection in the compression stroke is executed. As an example, the ratio of the hydrogen supply amount is 80% from the port injection type hydrogen injector I3 and 20% from the direct injection hydrogen injector I1.

  By the way, in an engine equipped with a conventional direct injection type fuel injector, moisture or the like produced by the combustion of the gaseous fuel adheres to the direct injection type fuel injector I1 due to a decrease in the outside air temperature or adiabatic expansion of the gaseous fuel accompanying the fuel injection. There is a possibility that the operation may be hindered by icing by rapid cooling. Further, in the rotary type engine as shown in FIG. 1, the lubricating oil for smoothly rotating the rotor enters the direct injection type fuel injector I1, so that the injection valve There was a risk of hindering operation.

  Therefore, in this embodiment, when the throttle valve 22 is started, the in-cylinder pressure of the working chamber E1 into which hydrogen is directly injected into the direct-injection hydrogen injector I1 is corrected to be increased, and the direct-injection hydrogen injector I1 is opened by the in-cylinder pressure of the working chamber E1. By assisting the shift in the direction, the direct injection hydrogen injector I1 can be opened regardless of the occurrence of moisture icing.

  In the present embodiment, when the hydrogen pressure at the time of starting the throttle valve 22 is low, the in-cylinder pressure of the working chamber E1 is corrected so as to reduce the increase correction amount with respect to when the hydrogen pressure is high. The rapid increase of the engine speed is suppressed, and the situation where the passenger feels uncomfortable is suppressed.

  Hereinafter, drive control of the direct injection type fuel injector I1 executed by the control unit 10 will be described with reference to the flowchart of FIG.

  First, for example, various signals detected by the configuration related to the engine main body 1 shown in FIG. 2 are read (step s1). Based on these signals, the control unit 10 performs an operation of selecting the hydrogen engine drive mode by the occupant. If it is determined whether or not a selection operation for the hydrogen engine drive mode has been performed (step s2: YES), the engine body 1 is started based on the signal read in step s1. Whether or not the ignition switch is turned on from the off state is determined (step s3).

  Here, if the control unit 10 determines that the engine main body 1 is being started (step s3: YES), a drive current should be supplied to the solenoid coil 6 (see FIGS. 3 and 4) of the direct injection hydrogen injector I1. An injection instruction signal is output to drive the direct injection type hydrogen injector I1 (see FIG. 1) (step s4).

  The temperature of the direct-injection hydrogen injector I1 can be considered to fluctuate substantially in relation to the coolant temperature of the engine main body 1, and the control unit 10 can detect the direct-injection-type hydrogen injector based on the signal detected by the water temperature sensor 18. The temperature of I1 can be indirectly determined. Here, for example, when the temperature threshold is set to 0 ° C. and the control unit 10 determines that the water temperature of the cooling water is lower than 0 ° C. (step s5: YES), it is in a predetermined low temperature state, and there is a possibility of freezing. Therefore, the operation of the timer means 25 is started, and the operation time of the starter 20 (see FIG. 2), that is, the time during which cranking is being executed is counted (step s6).

  On the other hand, if the control unit 10 determines that the water temperature is not less than 0 ° C., that is, not less than 0 ° C. (step s5: NO), the control unit 10 determines that the temperature of the direct injection hydrogen injector I1 has no possibility of freezing. To return.

  Here, in step s6, when a predetermined operation time (starter operation time threshold) set in advance has elapsed (step s7: YES), the control unit 10 causes the water adhering to the direct injection hydrogen injector I1 to be removed. It is determined that the direct-injection hydrogen injector I1 has not been opened due to icing. Then, based on the in-cylinder pressure increase correction amount determination map (see FIG. 7) in which the relationship between the value of the hydrogen pressure (residual pressure) detected by the pressure sensor 17 and the increase correction amount of the in-cylinder pressure in the working chamber E1 is preset. Thus, the control unit 10 determines an increase correction amount of the in-cylinder pressure of the working chamber E1 from the detection result of the pressure sensor 17. Further, the control unit 10 outputs a drive signal to the actuator 21 to open the throttle valve 22 so as to achieve a throttle opening corresponding to the increase correction amount of the in-cylinder pressure in the working chamber E1 (step s8).

  On the other hand, if the operation time of the starter is within the predetermined time (step s7: NO), the control unit 10 allows the direct injection type hydrogen injector I1 to be normally opened despite the possibility of freezing. Then, it is determined that the engine body 1 has shifted to the normal operation state, and the process is returned.

  In the in-cylinder pressure increase correction amount determination map, as shown in FIG. 7, these relations are empirically set so that the increase correction amount is reduced when the hydrogen pressure at the start is low when the hydrogen pressure is low. In the present embodiment, as shown in the figure, the increase correction amount has a relationship that is substantially proportional to the value of the hydrogen pressure.

  In this way, in step s8, by opening the throttle valve 22, the in-cylinder pressure in the working chamber E1 of the engine body 1 is increased and corrected. Therefore, in addition to the electromagnetic force by the solenoid coil 6, this in-cylinder pressure As a result of this increase, the movable portion 5b of the direct injection type hydrogen injector I1 shown in FIG. 3 is pressed in the direction of shifting upward. In other words, the upwardly corrected in-cylinder pressure can assist the upward shift of the movable portion 5b, so that the engine can be stably started regardless of moisture icing and without over-riching the air-fuel ratio. The direct injection type hydrogen injector I1 can be forcibly opened while securing the performance.

  After such an increase correction of the in-cylinder pressure in the working chamber E1, the control unit 10 determines that the direct-injection hydrogen injector I1 is opened and the engine body 1 has shifted to the normal operation state (step s9: YES), the control unit 10 outputs a drive signal for closing the throttle valve 22 to the actuator 21 to set the throttle opening state during idling (step s10), and the counter of the timer means 25 is set. Reset (step s11).

  Note that whether or not the engine body 1 has shifted to the normal operation state can be determined by the control unit 10 by setting a predetermined start determination rotation speed (for example, 500 rpm) in advance, and the engine speed sensor This can be indirectly determined from the detection result of 19 (see FIG. 2).

  When the engine main body 1 shifts to the normal operation state, the control unit 10 determines the direct injection type hydrogen injector I1 and the port according to the engine speed described above with reference to FIG. The driving of the injection-type hydrogen injector I3 is switched (step s12), and the process returns.

  When the control unit 10 determines in step s9 that the engine body 1 has not completely exploded and has not shifted to the normal operation state (step s9: NO), the occupant interrupts the operation of the ignition switch, and the engine body It is determined whether or not the start of 1 is abandoned (step s13). Here, if it is detected that the occupant continues to operate the ignition switch and attempts to start the engine body 1 (step s13: NO), the control unit 10 determines whether or not the engine body 1 has shifted to the normal operation state. Returning to step s9, the processes of steps s9 and s13 are repeated. On the other hand, if it is determined that the passenger interrupts the operation of the ignition switch and gives up starting the engine body 1 (step s13: YES), the control unit 10 returns the process.

  Further, when the control unit 10 determines in step s3 that it is not at the time of starting the engine body 1 (step s3: NO), the control unit 10 first determines FIG. 5 based on the detection result of the engine speed sensor 19. The driving of the direct injection type hydrogen injector I1 and the port injection type hydrogen injector I3 is switched in accordance with the engine speed described with reference (step s12), and the process returns.

  If it is determined in step s2 that the hydrogen engine drive mode is not selected by the occupant (step s2: NO), the control unit 10 opens the port injection type gasoline injector I2 (see FIG. 1). (Step 14), the gasoline engine drive mode is set, and the process returns.

  Even if the water adhering to the direct injection type hydrogen injector I1 freezes due to the above operation, the upward movement of the movable part 5b of the direct injection type hydrogen injector I1 is corrected by increasing the in-cylinder pressure of the working chamber E1 of the engine body 1. Since it is possible to assist, the direct injection hydrogen injector I1 can be opened while securing stable engine startability.

  By the way, when the hydrogen pressure is low, the action of gaseous hydrogen that presses the movable portion 5b downward to close the direct injection hydrogen injector I1 is small, so in this case, the increase correction amount of the in-cylinder pressure of the working chamber E1 Needs only a small amount. Further, an increase in the in-cylinder pressure of the working chamber E1 of the engine body 1 causes the engine speed to increase rapidly. If the degree of increase is large, the passenger may feel uncomfortable.

  Therefore, as in the present embodiment, when the hydrogen pressure at the time of starting is low, the cylinder internal pressure of the working chamber E1 is controlled so as to reduce the increase correction amount with respect to when the hydrogen pressure is high. Since the increase amount of the in-cylinder pressure of E1 is suppressed to a low level, it is possible to suppress a sudden increase in the engine speed and avoid a situation in which the passenger feels uncomfortable.

  Further, when the hydrogen pressure is low, the increase in the in-cylinder pressure of the working chamber E1 is suppressed to a low value, so that the differential pressure between the in-cylinder pressure of the working chamber E1 of the engine body 1 and the hydrogen pressure supplied to the direct injection hydrogen injector I1. Therefore, it is possible to avoid a situation in which gaseous hydrogen is hardly supplied into the working chamber E1 due to the increased in-cylinder pressure.

  Further, the control unit 10 determines the increase correction amount based on the in-cylinder pressure increase correction amount determination map as shown in FIG. 7, so that an accurate cylinder is determined based on the value of the hydrogen pressure detected by the pressure sensor 19. The internal pressure increase correction amount can be determined. Accordingly, it is possible to avoid a situation in which the increase correction amount is too large and the engine speed is increased unnecessarily, or the increase correction amount is too small and the opening operation of the direct injection hydrogen injector I1 fails.

  Further, in the present embodiment, in step s6, the operating state of the direct injection hydrogen injector I1 is detected, and when it is determined that the opening operation of the direct injection hydrogen injector I1 is not detected at the start based on this detection result, the engine Although the in-cylinder pressure of the working chamber E1 of the main body 1 is increased and corrected, even if it is determined in step s5 in FIG. 6 that the coolant temperature of the engine main body 1 is lower than 0 ° C. This is because the opening operation of the direct injection hydrogen injector I1 is not necessarily hindered by the influence of freezing. In other words, by detecting the operating state of the direct-injection hydrogen injector I1, it is possible to reliably avoid the situation of unnecessarily increasing and correcting the in-cylinder pressure of the working chamber E1, and to suppress the uncomfortable feeling given to the passenger as much as possible. It is doing.

  By the way, in this embodiment, the control unit 10 determines the possibility of icing based on the coolant temperature of the engine 1 in step s5 of FIG. In the case of the rotary type engine shown in the figure, if the main factor that hinders the opening operation of the direct injection hydrogen injector I1 is lubricating oil, the determination process in step s5 described above is omitted, and the in-cylinder pressure in the working chamber E1 increases. It can also be executed in steps s6 and s7 that determine whether correction is necessary based on the cranking time.

  Here, since the operation state of the direct injection hydrogen injector I1 is indirectly detected based on the cranking time using the timer means 25, it is easy to determine whether or not the direct injection hydrogen injector I1 is opened. Can be detected.

  In addition, by correcting the increase in the in-cylinder pressure in the working chamber E1 by controlling the throttle valve 22, the in-cylinder pressure in the working chamber E1 can be increased and corrected using an existing configuration without providing any new means. Can do.

  Note that the method for determining whether or not the direct injection hydrogen injector I1 is opened is not limited to the detection method based on the cranking time as described above. FIG. 8 is a diagram illustrating a drive current waveform when driving the direct injection hydrogen injector I1, and FIG. 9 is a control system diagram conceptually illustrating the engine body 1 and a configuration related thereto according to another embodiment. In addition, about each component shown in FIG. 9, about the same thing as the first embodiment mentioned above, the same code | symbol is attached | subjected and the description is abbreviate | omitted. In the direct injection type hydrogen injector I1 shown in FIG. 3, when a drive current is supplied to the solenoid coil 6 and the movable part 5b is shifted upward as shown in FIG. 4, the positional relationship between the solenoid coil 6 and the movable part 5b is Due to the deviation, electromagnetic induction is generated and a back electromotive force is generated. As a result, as shown in FIG. 8, the value of the drive current temporarily decreases to i1. When the direct injection hydrogen injector I1 cannot perform a predetermined opening operation due to the influence of freezing or lubricating oil, the value of the drive current increases with time as shown by a two-dot chain line in FIG.

  Therefore, as shown in FIG. 9, by providing the current detection means 26 for detecting the value of the drive current of the direct injection hydrogen injector I1, it is driven by the current detection means 26 instead of the processing of steps s6 and s7 in FIG. When it is detected that the current value has decreased, the control unit 10 can determine that the direct-injection hydrogen injector I1 has been opened.

  When the direct injection type hydrogen injector I1 can perform a predetermined opening operation, the control unit 10 keeps the drive current to be supplied at a minimum current value that can maintain the branch passage 5d in the upper position and keep the open state. Decrease to i2.

  The current detection means 26 can be constituted by, for example, an electric resistance element, and the current value can be easily and reliably lowered by the change in the voltage drop between the terminals of the electric resistance element, that is, the direct injection type hydrogen injector I1 is opened. Operation can be detected.

  In the above-described embodiment, the engine body 1 is a rotary type engine. However, the present invention is not limited to this, and the present invention may be a reciprocating engine. In particular, when the engine body 1 is a reciprocating engine, the means for increasing and correcting the in-cylinder pressure in the working chamber is a throttle valve as in the above-described embodiment, for example, Japanese Patent Laid-Open No. 59-188056, As disclosed in Japanese Patent Application Laid-Open No. 3-124923, etc., the compression ratio may be made variable by changing the position of the piston to make the volume of the working chamber variable.

  In this case, for example, according to the detection result of the fuel pressure, a control means for controlling the displacement amount of the piston is provided so that the increase correction amount of the in-cylinder pressure can be reduced when the fuel pressure at the start is low when it is high. The position of the piston may be changed stepwise.

  Further, the means for increasing and correcting the cylinder pressure in the working chamber may be constituted by a heating means for heating the working chamber. In this case, the in-cylinder pressure of the working chamber can be increased by heating the working chamber by the heating means, and the direct injection hydrogen injector I1 can also be heated by increasing the temperature in the working chamber. Thereby, since freezing can be melt | dissolved, the direct injection type hydrogen injector I1 can be opened in a shorter time.

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

In correspondence between the configuration of the present invention and the above-described embodiment,
The in-cylinder injection valve of the present invention corresponds to the direct injection type hydrogen injector I1,
Similarly,
The in-cylinder pressure correcting means and the air amount adjusting means correspond to the throttle valve 22,
The fuel pressure detection means corresponds to the pressure sensor 17,
The temperature detection means corresponds to the water temperature sensor 19,
The injection valve operating state detection means corresponds to the timer means 25 and the current detection means 26,
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. 1 is a control system diagram conceptually showing an engine body and a configuration related thereto according to an embodiment of the present invention. 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. Explanatory drawing showing the hydrogen injector employ | adopted according to each engine speed, and its injection timing. The flowchart which shows the drive control process of the direct injection type hydrogen injector performed by the control unit. The figure which shows the cylinder pressure increase correction amount determination map. The figure showing the drive current waveform at the time of driving a direct injection type hydrogen injector. The control system 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

DESCRIPTION OF SYMBOLS 1 ... Engine main body 17 ... Pressure sensor 18 ... Water temperature sensor 22 ... Throttle valve 25 ... Timer means 26 ... Current detection means I1 ... Gas hydrogen injection valve

Claims (7)

An engine fuel injection device including an in-cylinder injection valve that directly injects fuel into a working chamber,
In-cylinder pressure correcting means for correcting the in-cylinder pressure of the working chamber;
Fuel pressure detecting means for detecting fuel pressure supplied to the in-cylinder injection valve,
The in-cylinder pressure correcting means increases and corrects the in-cylinder pressure of the working chamber at the time of starting,
An engine fuel injection device that reduces an increase correction amount of the in-cylinder pressure when the fuel pressure at the start is low when the fuel pressure is low. The in-cylinder pressure correction unit is configured to correct the increase based on a cylinder pressure increase correction amount determination map in which a relationship between the fuel pressure detected by the fuel pressure detection unit and the increase correction amount of the cylinder pressure in the working chamber is set in advance. The engine fuel injection device according to claim 1, wherein the amount is determined. Temperature detecting means for detecting a temperature related to the in-cylinder injection valve;
The engine fuel injection device according to claim 1, wherein the in-cylinder pressure correcting means increases and corrects the in-cylinder pressure in the working chamber when a temperature at the time of starting is lower than a predetermined temperature. An injection valve operating state detecting means for detecting an operating state of the in-cylinder injection valve;
The engine fuel injection device according to claim 1, wherein when the opening operation of the in-cylinder injection valve is not detected at the time of starting, the in-cylinder pressure correcting means is operated. The engine fuel injection device according to claim 4, wherein the injection valve operating state detection means detects an operating state of the in-cylinder injection valve based on a cranking time. The in-cylinder injection valve is controlled to be opened and closed by supplying a drive current,
The engine fuel injection device according to claim 4, wherein the injection valve operating state detecting means detects an operating state of the in-cylinder injection valve based on the driving current. 2. The fuel injection device for an engine according to claim 1, wherein the in-cylinder pressure correcting means is constituted by an air amount adjusting means for adjusting an air amount supplied to the engine.

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