JPH07197857A - Fuel feed device for gas fuel engine - Google Patents

Abstract

PURPOSE:To prevent fuel from being brought into an overrich state owing to high pressure fuel gathering between a gas fuel control valve and a downstream shut-off valve during restarting after an engine stall occurs. CONSTITUTION:A hydrogen control valve 19 is located in a hydrogen feed passage 17 through which MH tanks 161-16n and a hydrogen injection valve 18 are intercommunicated. A first shut-off valve 20 closed when an engine is stopped is arranged in a spot situated upper stream from the hydrogen control valve 19 and a second shut-off valve 21 closed when the engine is stopped is located in a spot situated downstream therefrom. When the engine is brought into a stop through operation of an ignition switch or when an engine stall occurs, the first and second shut-off valves 20 and 21 are closed, and the hydrogen control valve 19 is closed with the ignition switch brought into an OFF- state. When, during the starting of an engine, the number of revolutions of an engine exceeds the given starting decision number of revolutions, the hydrogen valve 19 and the second shut-off valve 21 are opened and when a pressure between the hydrogen control valve 19 and the second shut-off valve 21 is reduced to a value lower than a set value, the first shut-off valve is opened.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a fuel supply system for a gas fuel engine.

[0002]

2. Description of the Related Art Conventionally, for example, JP-A-4-26205
As described in Japanese Patent Publication No. 1, an engine operated by a gaseous fuel such as hydrogen as a gasoline alternative fuel has been developed.

[0003]

By the way, for example, in a fuel supply device for a hydrogen engine using hydrogen as a fuel, a hydrogen storage tank (MH) containing a hydrogen storage alloy as a fuel storage unit is used.
Call it a tank. ) Is used to connect the MH tank and the fuel injection valve by a fuel supply passage, and a hydrogen control valve for controlling the fuel supply amount by adjusting the passage area of the fuel supply passage is provided in the fuel supply passage. Shut-off valves are installed upstream and downstream of the hydrogen control valve so as to completely shut off the fuel supply passage.These shut-off valves are closed when the ignition switch is shut off, and are shut off when the engine is stalled even when the ignition switch is connected. It is thought to do. In an engine equipped with such a fuel supply device, both shutoff valves are closed by the ignition switch being turned off when the engine is normally stopped, and at the same time the hydrogen control valve is closed. If it occurs, the hydrogen control valve remains open and only the shutoff valve closes.Therefore, high-pressure hydrogen upstream of the hydrogen control valve flows downstream, causing dead volume between the hydrogen control valve and the shutoff valve on the downstream side. Accumulates in the combustion chamber of the engine when the engine is restarted, which results in overriching and poor starting.

The present invention is intended to solve the above-mentioned problems, and high-pressure fuel accumulated between the gas fuel control valve and the shutoff valve on the downstream side is supplied at the time of restart after engine stall. The purpose is to prevent the startability from deteriorating due to the air-fuel ratio overrich.

[0005]

A fuel supply device for a gas fuel engine according to the present invention is a gas fuel for a hydrogen engine or the like which supplies the gas fuel stored in a gas fuel storage portion to the engine at a predetermined timing by a gas fuel injection valve. In a fuel supply device for an engine, a first cutoff valve that is closed when the engine is stopped, and a passage area of the passage in a fuel supply passage that connects the gaseous fuel injection valve and the gaseous fuel storage portion in order from the gaseous fuel storage portion side. And a second cutoff valve that closes when the engine is stopped, and a control valve closing control means that closes the gas fuel control valve when the engine is stopped, a first cutoff valve, and A shutoff valve control means for controlling the second shutoff valve to close when the engine is stopped and to open it when the engine starts, and a pressure for detecting the fuel pressure between the gas fuel control valve and the second shutoff valve. Detecting means, starting-time pressure determining means for determining whether or not the fuel pressure detected by the pressure detecting means at engine startup is equal to or greater than a set value, and output of the pressure determining means, and the fuel pressure is set at the above-mentioned setting at engine startup. When the value is equal to or more than the value, a first shutoff valve opening control limiting means for limiting the opening operation of the first shutoff valve by the shutoff valve controlling means is provided.

In the above construction, the control valve closing control means particularly closes the gas fuel control valve when the ignition switch is shut off, and the shutoff valve control means shuts off the first shutoff valve and the second shutoff valve when the ignition switch is shut off. It is advantageous to apply when the engine is closed and the engine is closed when the engine speed is equal to or lower than a predetermined engine stall determination engine speed.

[0007]

According to the present invention, the first shutoff valve and the second shutoff valve are opened during engine operation, and the gas fuel control valve adjusts the passage area of the fuel supply passage according to the required fuel supply amount,
The gaseous fuel supplied from the gaseous fuel reservoir is decompressed by the gaseous fuel control valve and then supplied to the engine by the gaseous fuel injection valve. Then, when the ignition switch is shut off and the engine is stopped, the first shutoff valve and the second shutoff valve are closed, and at the same time the gas fuel control valve is closed to shut off the fuel supply passage. Is opened and the second control valve is opened, and the first shutoff valve is also opened because the fuel pressure between the gaseous fuel control valve and the second shutoff valve is usually lower than the set value.
Further, when an engine stall occurs, the first shutoff valve and the second shutoff valve are closed, and when the engine is restarted thereafter, only the second shutoff valve is opened first, and the opening operation of the first shutoff valve is restricted. The first shutoff valve is opened normally only when the fuel pressure between the gaseous fuel control valve and the second shutoff valve falls below the set value.

When the engine stall occurs, the first shutoff valve and the second shutoff valve are closed as described above, but the gaseous fuel control valve is not closed. Therefore, the high-pressure gaseous fuel between the first shutoff valve and the gaseous fuel control valve is gas. It accumulates in the dead volume between the fuel control valve and the second shutoff valve. However, when the engine is restarted, only the second cutoff valve downstream of the gas fuel control valve is opened while the first cutoff valve is closed, so that the gaseous fuel accumulated in the dead volume is first discharged into the combustion chamber of the engine, The first shutoff valve on the upstream side is opened, and the normal fuel supply is started, so that overrich is prevented.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall view of an embodiment of the present invention.
This embodiment is applied to a rotary engine using hydrogen as a fuel, and the rotary engine shown in FIG. 1 has a trilobal inner envelope surface in a rotor housing 2 having a peritrochoid curve as an inner peripheral surface. The rotor 3 is disposed, and three working chambers 4 are formed by the inner peripheral surface of the rotor housing 2, the outer peripheral surface of the rotor 3, and side housings (not shown) disposed on both side surfaces of the rotor housing 2. As the working chamber 4 changes its volume with a phase difference in accordance with the rotation of 3, the intake, compression, expansion, and exhaust strokes are performed, and the output thereof is taken out from the eccentric shaft 5. An intake port 6 is provided in the intake stroke side working chamber, an exhaust port 7 is provided in the exhaust stroke side working chamber, and an intake port 6 is provided in the intake stroke side working chamber. Hydrogen supply port 8 is provided independently at a position adjacent to the leading side of the 6. An intake passage 10 communicating with the air cleaner 9 is connected to the intake port 6, and the intake passage 10 is provided with an electrically driven throttle valve 11 for adjusting the intake air amount.
An air flow sensor 12 that detects the amount of intake air is provided upstream of the throttle valve 11. An exhaust passage 13 is connected to the exhaust port 7, and the exhaust passage 1
3, a catalytic converter 14 is provided, and an O ₂ sensor 15 for detecting the air-fuel ratio of the engine based on the oxygen concentration in the exhaust gas is provided on the inlet side of the catalytic converter 14.

The hydrogen supply port 8 is connected to a hydrogen supply passage 17 for guiding hydrogen from the hydrogen storage portion 16 composed of a plurality of MH tanks 16 _{1 to} 16 _n . The hydrogen supply passage 17 and the hydrogen supply port 8 are connected to each other. A hydrogen injection valve 18 configured to inject hydrogen in synchronization with engine rotation is installed in the section. In addition, the hydrogen supply passage 17 has the passage 17
An electric hydrogen control valve 19 for adjusting a passage area of the fuel cell and controlling a gas fuel supply amount is provided, and a first cutoff valve 20 is provided between the hydrogen control valve 19 and the hydrogen storage section 16 and is closed when the engine is stopped. However, a second shutoff valve 21 that is closed when the engine is stopped is provided between the hydrogen control valve 19 and the hydrogen injection valve 18. In the hydrogen supply passage 17, a first pressure sensor 22 is provided between the hydrogen storage unit 16 and the first shutoff valve 20, and a second pressure sensor 22 is provided between the hydrogen control valve 19 and the second shutoff valve 22. 23 are provided.

The hydrogen storage section 16 is composed of a plurality of MH tanks 1.
6 _{1 to} 16 _n are arranged in parallel, and each MH tank 16 _{1 to} 16 _n has a hydrogen storage alloy (for example, T
iFe, LaNi, TiMn ₁₅ , MmNiCr, MmN
i ₅ ) are built in, and hydrogen is released at a certain temperature or higher to obtain a predetermined hydrogen discharge pressure.

Engine cooling water is circulated as a heat medium in each of the MH tanks 16 _{1 to} 16 _n . That is, the heat medium passage 24 connected to the engine cooling system is provided, and the heat medium passage 24 is configured so as to circulate through the MH tanks 16 _{1 to} 16 _n . A heat medium pump 25 that circulates the engine cooling water is installed in the upstream portion of the heat medium passage 24 near the extraction position from the engine cooling system. In addition, bypassing the engine cooling system, the MH tanks 16 _{1 to} 16 _n
A bypass passage 26 that communicates the upstream portion and the downstream portion of the heat medium passage 24 is provided so as to circulate the heat medium, and heat from the engine cooling system is provided at a connection position between the bypass passage 26 and the upstream portion of the heat medium passage 24. A thermo valve 27 is provided to maintain the heat medium temperature at a predetermined value (for example, 40 ° C.) by adjusting the mixing ratio of the medium and the heat medium that bypasses the engine cooling system.

In the drawing, 28 is an engine control unit. This engine control unit 2
8, an engine rotation signal is input as control information from a rotation sensor (not shown), an intake air amount signal signal is input from an air flow sensor 12, an air-fuel ratio signal is input from an O ₂ sensor 15, and the first and second Gas pressure signals are input from the pressure sensor, and in addition, a starter switch signal, an ignition switch signal, an accelerator opening signal from the accelerator sensor 29, and the like are input. Then, the throttle valve 11 is controlled based on these information, the hydrogen control valve 19 is controlled, the first shutoff valve 20 and the second shutoff valve 21 are controlled, and the heat medium pump 25 is controlled. Control is performed.

FIG. 2 is a detailed view of the hydrogen injection valve 18. The hydrogen injection valve 18 is composed of a poppet valve 31, and is opened / closed by a cam 33 of an injection valve driving cam shaft 32 that is synchronously driven by the eccentric shaft 5, and is connected to an upstream passage 34 communicating with the hydrogen supply passage 17 side. And the downstream passage 35 communicating with the hydrogen supply port 8 are communicated at a predetermined timing to inject hydrogen into the working chamber 4.

FIG. 3 shows the opening period (IP) of the intake port 6.
And hydrogen supply port 8 opening period (HP) and hydrogen injection valve 1
8 shows the valve opening period (TV). Hydrogen injection valve 18
Is opened after the intake bottom dead center (BDC) has been completely closed to prevent backfire and the intake port 6 is completely closed until the compression top dead center (TDC) is reached. This period is the hydrogen supply period.

FIG. 4 is a detailed view of the hydrogen control valve 19. The hydrogen control valve 19 is driven by a step motor 37 that operates in response to a control signal, and includes a valve member 39 that is horizontally movable inside a casing 38. A base end portion of the valve member 39 is provided. To the step motor 37
Are connected. In the casing 38, an inlet passage 40 and an outlet passage 41, which communicate with the upstream side and the downstream side of the fuel supply passage 17, respectively, and a valve hole 4 which communicates these.
2 is formed, and a valve body 39a having a tapered peripheral surface is provided at the tip of the valve member 39.
9a is inserted into the valve hole 42, the spring 4
The valve member 39 urges the valve 3 in the valve closing direction (to the right in the drawing). A bypass passage 44 is formed in the casing 38 to bypass the valve body 39a and connect the inlet passage 40 and the outlet passage 41, and the bypass passage 44 is provided with a needle-shaped on-off valve 45. This on-off valve 4
Reference numeral 5 is connected to a negative pressure responsive actuator 46 that introduces an intake negative pressure downstream of the throttle valve, opens when the intake negative pressure downstream of the throttle is equal to or higher than a predetermined value, and closes when the intake negative pressure is lower than the predetermined value. .

When the engine is operating, the first shutoff valve 20 and the second shutoff valve 21 are opened, and the hydrogen discharged from the MH tanks 16 _{1 to} 16 _n is passed through the hydrogen supply passage 17 whose passage area is controlled by the hydrogen control valve 19. The hydrogen is injected into the hydrogen supply port 8 by the hydrogen injection valve 18 in synchronism with the engine rotation, and is supplied to the working chamber 4 of the engine 1 at the above timing. Further, the air is introduced into the intake passage 10 through the air cleaner 9, and is guided to the intake port 6 through an electric throttle valve 11 that opens and closes according to an opening signal from the engine control unit 28, and operates at a predetermined timing. It is supplied to the chamber 4.

In controlling the hydrogen control valve 19, the step motor 37 is controlled according to the accelerator opening, the engine speed, the detection value of the first pressure sensor 22 for detecting the pressure upstream of the first shutoff valve 20, and the like. To be done.

Further, when the engine is stopped, the first shutoff valve 20 and the second shutoff valve 21 are closed in response to a signal for turning off the ignition switch, and when the engine speed falls below a predetermined engine stall determination speed. The
The hydrogen control valve 19 is also closed. When the engine is started, the starter switch ON signal is input, and when the engine speed exceeds the predetermined start determination speed, the hydrogen control valve 19 is opened and the second cutoff valve 21 is opened.
Further, the pressure between the hydrogen control valve 19 and the second shutoff valve 21 is detected by the second pressure sensor 23, and the first shutoff valve is opened when the detected value becomes lower than the set value.

FIG. 5 shows the first cutoff valve 20 in the above embodiment.
7 is a flowchart for executing opening / closing control of the second cutoff valve 21.

This flow is composed of steps S1 to S12. It starts and it is checked in S1 whether the starter switch signal is ON. And starter switch ON
If so, it is determined in S2 whether the engine speed (Ne) has become higher than a predetermined start determination speed (N ₁ ),
If Ne is equal to or less than N ₁ , return as it is, and Ne is N _1.
When it becomes higher, go to S3. Then, in S3, the second shutoff valve 21 (V ₂ ) is opened, and in S4, the hydrogen control valve 19 and the second
It is determined whether the pressure (P) between the shutoff valve 21 and the shutoff valve 21 is lower than the set value (P ₁ ), and if P is P ₁ or more, the process returns as it is. If P is lower than P ₁ , S5 is performed. First
Open the shutoff valve 20 (V ₁ ).

When the starter switch is OFF in S1, it is checked in S6 whether the ignition switch signal is ON. When the ignition switch is ON, it is determined in S7 whether the engine speed (Ne) is higher than a predetermined engine stall judgment engine speed (N ₂ ). If Ne is higher than N ₂ , it means that the engine is in a stall operation. Then, the first shutoff valve 20 (V ₁ ) is opened in S8, and the second shutoff valve 21 is opened in S9.
Open (V ₂ ). If Ne is equal to or less than N ₁ , it means that the engine is stalled, so that the first shutoff valve 20 (V
₁ ) is closed, and the second shutoff valve 21 (V ₂ ) is closed in S12.

Although the above embodiment has been described as applied to a rotary engine using hydrogen as a fuel, the present invention can be applied to other hydrogen engines.

The present invention can also be applied to an engine using a gaseous fuel other than hydrogen.

[0026]

Since the present invention is configured as described above, in a gas fuel engine, high pressure accumulated between the gas fuel control valve and the shutoff valve on the downstream side at the time of restart after engine stall or the like. It is possible to prevent the startability and the like from being deteriorated due to overrich due to the supply of fuel.

[Brief description of drawings]

FIG. 1 is an overall view of an embodiment of the present invention

FIG. 2 is a detailed view of a hydrogen injection valve according to an embodiment of the present invention.

FIG. 3 is a timing chart showing an opening period of an intake port and a hydrogen supply port and a valve opening period of a hydrogen injection valve according to an embodiment of the present invention.

FIG. 4 is a detailed view of a hydrogen control valve according to an embodiment of the present invention.

FIG. 5 is a flowchart of shutoff valve control according to an embodiment of the present invention.

[Explanation of symbols]

1 rotary engine 8 hydrogen supply port 16 hydrogen storage unit 16 ₁ ~ 16 _n MH tank 17 hydrogen supply passage 18 hydrogen injection valve 19 hydrogen control valve 20 first shut-off valve 21 second cutoff valve 22 first pressure sensor 23 second pressure sensor

Claims (3)

[Claims] 1. A fuel supply device for a gas fuel engine, which supplies a gaseous fuel stored in a gaseous fuel storage section to an engine at a predetermined timing by a gaseous fuel injection valve, wherein the gaseous fuel injection valve and the gaseous fuel storage section are provided. A first cutoff valve that is closed when the engine is stopped, a gas fuel control valve that controls the gas fuel supply amount by adjusting the passage area of the passage, and an engine stop A second shutoff valve that is closed at times is provided, and control valve closing control means that closes the gas fuel control valve when the engine is stopped, and control that closes the first shutoff valve and the second shutoff valve when the engine is stopped and opens when the engine is started Shut-off valve control means, pressure detection means for detecting the fuel pressure between the gaseous fuel control valve and the second shut-off valve, and the pressure detection means when the engine is started. And a shut-off valve control means for receiving the output of the pressure determination means at the time of starting and for determining whether the fuel pressure detected by 1. A fuel supply system for a gas fuel engine, comprising: a first shutoff valve open control limiting means for limiting the opening operation of the first shutoff valve by the above. 2. The control valve closing control means closes the gaseous fuel control valve when the ignition switch is shut off, and the shutoff valve control means closes the first shutoff valve and the second shutoff valve when the ignition switch is shut down. The fuel supply device for a gas fuel engine according to claim 1, wherein the engine speed is closed when the engine speed is equal to or lower than a predetermined engine stall determination speed. 3. The fuel supply device for a gas fuel engine according to claim 1, wherein the gas fuel is hydrogen.