JP4715651B2 - Engine gas fuel system - Google Patents

Description

  The present invention relates to a gaseous fuel system for an engine.

  Conventionally, engines using gaseous fuel such as hydrogen gas and natural gas are known.

  For example, in the engine disclosed in Patent Document 1, a pair of gaseous fuel supply systems is provided in each bank of the V-type engine. Each fuel supply system is provided with a fuel tank disposed in the trunk room of the vehicle and a shut-off valve disposed on the downstream side of the fuel tank to prevent fuel leakage.

  By the way, when a failure occurs in the gaseous fuel supply system, the engine rapidly loses output, and the vehicle becomes inoperable. Therefore, it is necessary to provide a fault tolerance function capable of degenerate operation even when an abnormality occurs in the gaseous fuel supply system.

Therefore, in Patent Document 1, a communication path that communicates the upstream side of each shut-off valve of two coexisting gas fuel supply systems is formed, and the open / close control of this communication path enables a degenerate operation during an abnormality. Yes.
JP 2003-269257 A

  However, using a plurality of gaseous fuel supply systems to perform the degenerate operation is extremely expensive because the entire apparatus has a redundant configuration. Moreover, since the gaseous fuel supply system is enlarged, the degree of freedom in layout is also reduced.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a gas fuel system for an engine that has a high degree of freedom in layout and enables a degenerate operation with an inexpensive and simplified configuration.

In order to solve the above-described problems, the present invention provides a main tank that stores gaseous fuel, a main main valve that opens and closes the main tank, and the main main valve that is connected to the main main valve, and the gaseous fuel in the main tank is burned by the engine A supply pipe for supplying to the chamber, a shut-off valve disposed on the downstream side of the main tank of the supply pipe, opening and closing the supply pipe, a gas provided from the supply pipe on the downstream side of the shut-off valve In the gas fuel system for an engine, comprising: a gas fuel injection means for injecting fuel; and a control means for controlling at least the injection timing of the gas fuel injection means and the opening and closing timings of the main main valve and the shutoff valve. An auxiliary pipe connected downstream from the shutoff valve, and a sub tank provided at the upstream end of the auxiliary pipe and capable of supplying gaseous fuel to the engine via the auxiliary pipe; And a sub source valve for opening and closing the sub-tank under the control of said control means, and abnormality detecting means for outputting to the control unit detects an abnormality of the supply pipe, the filling amount of the gaseous fuel filled in the subtank A filling amount detecting means for detecting and inputting to the control means; and an operating state detecting means for detecting and outputting the operating state of the engine to the control means , wherein the control means outputs to the output of the abnormality detecting means. If it is determined that the supply pipe is normal based on this, the main original valve and the shutoff valve are opened and the sub original valve is closed to control fuel injection, while the output of the abnormality detecting means is if it is determined the supply pipe to be abnormal on the basis of, by opening the sub-main valve closes the main source valve and the shut-off valve controls the fuel injection, the abnormality detection The supply pipe is determined to be normal based on the output of the means, the filling amount in the sub tank is less than a predetermined value, and the fuel cut is performed based on the output of the operating state detection means A gas fuel system for an engine is characterized in that, when it is determined that a condition is satisfied, a fuel replenishment operation is performed for communicating the main tank and the sub tank via the supply pipe .
In this aspect, during normal operation (a state in which the control means determines that the supply pipe is normal), gaseous fuel is supplied from the main tank to the engine via the supply pipe. On the other hand, when an abnormality occurs in the supply pipe, the abnormality detection means detects this abnormality and inputs it to the control means. Since the control means closes the main main valve and the shut-off valve and opens the sub original valve based on the detection by the abnormality detection means, the gaseous fuel is supplied from the sub tank to the engine. As described above, in this aspect, the subtank and the auxiliary pipe for the degenerate operation are arranged on the downstream side of the shutoff valve, so that the open / close control of the two gas fuel supply systems can be performed by the open / close control of the single shutoff valve. become. As a result, the degree of freedom in layout is improved and the cost can be reduced. The control means also functions as a fuel replenishing means for the sub tank, so that fuel can be replenished from the main tank to the sub tank, and there is no need to provide a fuel replenishing path to the sub tank, and the entire system is downsized. To do. Moreover, since the fuel supply operation is executed when the fuel cut condition is satisfied, there is no possibility of adversely affecting the operation of the engine when fuel is supplied from the main tank to the sub tank.

In favorable preferable embodiment, the sub-tank, the shut-off valve, and the auxiliary pipe is disposed in an engine room of a vehicle. In this aspect, since the subtank and the like are laid out in the engine room that is not easily affected by a stepping stone or the like, it is possible to prevent as much as possible a failure during the degenerate operation.

  As described above, according to the present invention, the sub-tank and the auxiliary pipe for the degenerate operation are arranged on the downstream side of the shut-off valve, so that the open / close control of the two gas fuel supply systems by the single shut-off valve As a result, the degree of freedom in layout is high, and a remarkable effect is achieved in that a degenerate operation is possible with an inexpensive and simplified configuration.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic plan view showing a schematic configuration of a gaseous fuel system for an engine according to an embodiment of the present invention. FIG. 2 is a block diagram schematically showing a gaseous fuel system of the engine.

  Referring to FIG. 1, vehicle 10 shown in FIG. 1 is provided with an engine room 11 and a trunk room 12. In the engine room 11, an engine 14 supported by a frame (not shown) is disposed.

  Referring to FIG. 2, the engine 14 is a rotary engine. The engine 14 is formed between two rotor housings (schematically shown in FIG. 2 in an unfolded state) 15 which are overlapped and integrated between three side housings (not shown). This is a two-rotor type in which two rotor accommodating chambers 16 are formed.

  The rotor storage chamber 16 has a bowl shape having an inner peripheral surface of a trochoid, and a rotor 17 is stored therein.

  The rotor 17 is a special cast iron product and rotates eccentrically in a state in which an apex seal fixed to each top portion is always in sliding contact with the inner peripheral surface of the rotor accommodating chamber 16. The rotor 17 defines three combustion chambers in the rotor storage chamber 16. A pair of spark plugs 18 and a gaseous fuel injection valve 19 are connected to the rotor housing 15 corresponding to these three combustion chambers. The gaseous fuel injection valve 19 is a direct injection type that directly injects gaseous fuel (hydrogen in this embodiment) supplied from the gaseous fuel system 30 which is the essence of this embodiment into the combustion chamber.

  An internal gear is formed at the center of the rotor 17, and an accurate orbit is maintained by meshing with a fixed gear formed on the side housing. Further, an eccentric shaft 20 is fitted in the central portion of the rotor 17.

  An intake pipe 21 and an exhaust pipe (not shown) are connected to each rotor accommodating chamber 16. The fresh air is introduced into the combustion chamber through the intake pipe 21 and the burned gas is discharged through the exhaust pipe.

  Each intake pipe 21 is provided with a port injection valve 22 for injecting gasoline fuel. Each intake pipe 21 branches from the downstream end of the intake upstream pipe 23 for each rotor accommodating chamber 16. The intake upstream pipe 23 is provided with a throttle valve 24 and is driven to open and close by an actuator 25.

  The spark plug 18, the fuel injection valves 19 and 22, and the actuator 25 are configured to be operated and controlled by a control unit (PCM) 100 described in detail later.

  Next, a gaseous fuel system 30 for supplying gaseous fuel to the gaseous fuel injection valve 19 will be described with reference to FIG.

  As shown in FIG. 1, the gaseous fuel system 30 includes a main tank 31 disposed in the trunk room 12. The volume of the main tank 31 is, for example, 60 liters, and the inside is filled with hydrogen as a gaseous fuel at about 35 MPa.

  A main main valve 32 that can be opened and closed by electromagnetic control is attached to the main tank 31, and the main main valve 32 extends in the front-rear direction of the vehicle 10 and is connected to the gaseous fuel injection valve 19. 33. On the upstream side of the supply pipe 33 (in the trunk room 12), a pressure reducing valve 34 for reducing the gaseous fuel discharged from the main main valve 32 to, for example, 0.6 MPa is provided.

  FIG. 3 is a schematic cross-sectional view showing the configuration of the pressure reducing valve 34 according to this embodiment.

  Referring to FIG. 3, the pressure reducing valve 34 connects the introduction pipe 34 a connected to the main main valve 32, the discharge pipe 34 b for discharging the decompressed gaseous fuel to the supply pipe 33, and both pipes 34 a and 34 b. A casing 34c is integrally provided. A pressure regulating valve 34d is disposed between the introduction pipe 34a and the discharge pipe 34b. The pressure regulating valve 34d is driven by a diaphragm 34e disposed in the casing 34c. The diaphragm 34e is urged in a direction to open the pressure regulating valve 34d by a spring 34g in a spring accommodating portion 34f formed integrally with the casing 34c. The spring accommodating portion 34f is formed with a communication hole 34h communicating with the atmosphere, and the surface on the side urged by the diaphragm 34e and the spring 34g receives atmospheric pressure. On the other hand, a partition plate 34i for supporting the pressure regulating valve 34d is formed in the casing 34c, and gaseous fuel is communicated with the introduction pipe 34a in the space opposite to the spring of the diaphragm 34e. A communication hole 34j is formed. Therefore, the diaphragm 34e receives the pressure of the gaseous fuel that has passed through the pressure regulating valve 34d from the opposite surface of the spring 34g by the gaseous fuel introduced from the introduction pipe 34a. With this configuration, the pressure reducing valve 34 can reduce the gaseous fuel in the main tank 31 introduced from the introduction pipe 34 a to 0.6 MPa, discharge it from the discharge pipe 34 b, and supply it to the supply pipe 33. ing. In the illustrated example, 34k in FIG. 3 is a heat radiation fin fixed to the casing 34c.

  Referring to FIG. 1, a shutoff valve 35 disposed in the engine room 11 is connected to the supply pipe 33. The shut-off valve 35 opens and closes the supply pipe 33 by electromagnetic control, and thereby prevents gaseous fuel from leaking when the engine 14 is stopped. In the present embodiment, the shut-off valve 35 performs various functions in the gaseous fuel system 30 as described later.

  An auxiliary pipe 36 is connected downstream of the shutoff valve 35 of the supply pipe 33. A sub tank 37 is connected to an upstream end of the auxiliary pipe 36 via a sub original valve 38 that can be electromagnetically controlled to open and close. The sub tank 37 is a fuel container for degenerate operation accommodated in the engine room 11. The sub tank 37 has a volume of, for example, 2 liters, and is filled with about 0.6 MPa of gaseous fuel.

  Next, in order to control the operating state of the gaseous fuel system 30, a main tank pressure sensor SW1 and a sub tank pressure sensor SW2 are attached to the main tank 31 and the sub tank 37, respectively. Further, a supply pipe pressure sensor SW <b> 3 for detecting gas leakage is disposed in the supply pipe 33 in the engine room 11 and upstream of the shut-off valve 35. Each pressure sensor SW <b> 1 to SW <b> 3 is connected to the control unit 100 of the engine 14.

  1 and 2, control unit 100 is a unit having a microprocessor, a main storage device, an auxiliary storage device, and an input / output device as main elements. Input elements connected to the control unit 100 include an accelerator opening sensor SW4 and an engine speed sensor SW5 in addition to the pressure sensors SW1 to SW3 described above. Output elements connected to the control unit 100 include the above-described spark plug 18, fuel injection valves 19 and 22, actuator 25, main original valves 32 and 38 of the tanks 31 and 37, and shut-off valve 35. It is included. In the illustrated embodiment, a failure display lamp 39 indicating a failure of the gaseous fuel system 30 is provided on an unillustrated instrument panel, and this failure display lamp 39 is also included in the output element of the control unit 100. ing.

  Next, control of the gaseous fuel system 30 according to the present embodiment will be described with reference to FIGS. 4 and 5.

  FIG. 4 is a flowchart of the gaseous fuel system 30 according to the present embodiment.

  Referring to FIG. 4, control unit 100 waits for the engine to start operation (specifically, an ignition switch (not shown) is connected) (step S20). When the engine starts operation, gaseous fuel Control of the system 30 is started. Specifically, the main main valve 32 and the cutoff valve 35 of the main tank 31 are opened, and the sub original valve 38 of the sub tank 37 is closed (step S21). Thereby, normal operation control by gaseous fuel is performed.

  Next, the control unit 100 monitors based on the output of the supply pipe pressure sensor SW3 (step S22), and based on whether the gaseous fuel in the supply pipe 33 is less than 0.6 MPa from the output of the pressure sensor SW3. Then, abnormality determination is executed (step S23).

  If an abnormality is detected, that is, if the gaseous fuel in the supply pipe 33 is below 0.6 MPa, the main main valve 32 and the shutoff valve 35 of the main tank 31 are closed (step S24). Next, the sub main valve 38 of the sub tank 37 is opened (step S25), and the failure display lamp 39 is turned on to notify the driver of the failure (step S26). Note that step S26 may be executed immediately when an abnormality is determined at the time of the determination in step S23.

  Thereby, even when a failure occurs in the supply pipe 33, the gaseous fuel is supplied from the sub tank 37 disposed in the engine room 11 to the path downstream of the shutoff valve 35. It is possible to take measures such as performing a degenerate operation and stopping the vehicle 10 on the shoulder by the gaseous fuel supplied by the vehicle.

  On the other hand, if no abnormality is detected in step S23, the control unit 100 executes the routine after step S22 until the engine 14 is stopped after executing the fuel supply operation subroutine (step S30) (step S30). S31) When the engine 14 is stopped, the main main valve 32 and the shutoff valve 35 of the main tank 31 are closed, and the control is finished (step S32).

  Next, the fuel supply operation subroutine (step S30) will be described with reference to FIG. FIG. 5 is a flowchart showing the fuel supply operation subroutine (step S30) of FIG.

  Referring to FIG. 5, in this subroutine, control unit 100 reads the accelerator opening and the engine speed from the outputs of accelerator opening sensor SW4 and engine speed sensor SW5 (step S300). Based on the value read in step S300, the control unit 100 determines whether or not the fuel cut condition is satisfied (step S301). Here, the fuel cut condition refers to a case where the accelerator is not depressed and the engine speed is equal to or higher than a predetermined speed (for example, 1800 rpm).

  When such a condition is satisfied, the control unit 100 reads the pressure of the sub tank 37 from the output of the pressure sensor SW2 (step S302), and determines whether or not the fuel supply condition is satisfied (step S303). Here, the fuel supply condition refers to a case where the pressure in the sub tank 37 is reduced to 0.4 MPa or less, for example.

  If the fuel supply condition is satisfied, the control unit 100 opens the sub main valve 38 of the sub tank 37 with the main main valve 32 and the shutoff valve 35 of the main tank 31 open (step S304). As a result, the main tank 31 and the sub tank 37 communicate with each other via the supply pipe 33 and the auxiliary pipe 36, and gaseous fuel is supplied from the main tank 31 to the sub tank 37 due to an internal pressure difference therebetween. The control unit 100 monitors the pressure in the sub tank 37 from the output of the pressure sensor SW2 (step S305), and determines whether the supply end condition is satisfied (step S303). Here, the supply end condition refers to a case where the pressure in the sub tank 37 exceeds 0.59 MPa, for example. If the supply end condition is satisfied, the control unit 100 closes the sub original valve 38 of the sub tank 37 and returns to the main routine. On the other hand, if the supply end condition is not satisfied in step S306, the control returns to step S300. This is a measure for avoiding communication between the main tank 31 and the sub tank 37 in an operation state in which fuel injection is performed. Further, if the fuel cut condition is not satisfied in step S301, or if the fuel supply condition is not satisfied in step S303, it is determined whether or not the sub tank 37 is closed (step S308). When 37 is open, the process returns to the main routine via step S307, and when it is closed, the process returns to the main routine as it is.

  As described above, in the present embodiment, during normal operation (in a state where the control unit 100 as the control unit determines that the supply pipe 33 is normal based on the output of the pressure sensor SW3), the gas is discharged from the main tank 31. Fuel is supplied to the engine 14 via the supply pipe 33. On the other hand, when an abnormality occurs in the supply pipe 33, the pressure sensor SW3 detects this abnormality and inputs it to the control unit 100. Since the control unit 100 closes the main main valve 32 and the shutoff valve 35 and opens the sub main valve 38 based on the detection of the pressure sensor SW3, the gaseous fuel is supplied from the sub tank 37 to the engine 14. As described above, in this embodiment, the subtank 37 and the auxiliary pipe 36 for the degenerate operation are arranged on the downstream side of the shutoff valve 35, so that two gas fuel supply systems can be controlled by opening / closing the single shutoff valve 35. Open / close control is possible. As a result, the degree of freedom in layout is improved and the cost can be reduced.

  Further, in the present embodiment, the pressure sensor SW2 is provided as a filling amount detecting means for detecting the filling amount of the gaseous fuel filled in the sub tank 37 and inputting it to the control unit 100. The control unit 100 includes the pressure sensor SW3. When it is determined that the supply pipe 33 is normal and the filling amount in the sub-tank 37 is below a predetermined value, the supply pipe 33 is based on the detected value of the pressure sensor SW2, as described with reference to FIG. A fuel replenishment operation is performed in which the main tank 31 and the sub tank 37 are communicated with each other via the main tank 31. For this reason, in this embodiment, the control unit 100 also functions as a fuel replenishing unit for the sub tank 37, and fuel can be replenished from the main tank 31 to the sub tank 37. As a result, there is no need to provide a fuel supply path to the sub tank 37, the entire system is downsized, and the degree of layout is improved.

  In the present embodiment, as an engine operating state detection means, an accelerator opening degree detection sensor SW4 that detects the accelerator opening degree, or an engine rotation number sensor SW5 that detects the engine speed and outputs a detection signal to the control unit 100. The control unit 100 executes the fuel supply operation when it is determined that the fuel cut condition is satisfied based on the outputs of the sensors SW4 and SW5. Therefore, in the present embodiment, there is no possibility of adversely affecting the operation of the engine 14 when fuel is supplied from the main tank 31 to the sub tank 37.

  In the present embodiment, the sub tank 37, the shut-off valve 35, and the auxiliary pipe 36 are arranged in the engine 14 room of the vehicle. For this reason, in the present embodiment, since the sub tank 37 and the like are laid out in the engine 14 room that is not easily affected by a stepping stone or the like, it is possible to prevent a failure during the degenerate operation as much as possible.

  As described above, in the present embodiment, the sub-tank 37 and the auxiliary pipe 36 for the degenerate operation are arranged on the downstream side of the shut-off valve 35, so that two systems of gaseous fuel can be controlled by opening / closing the single shut-off valve 35. As a result, it is possible to control the opening and closing of the supply system. As a result, there is a remarkable effect that the degree of freedom of the layout is high, and the degenerate operation is possible with an inexpensive and simplified configuration.

1 is a schematic plan view showing a schematic configuration of a gaseous fuel system for an engine according to an embodiment of the present invention. It is the block diagram which showed typically the gaseous fuel system of the same engine. It is a section schematic diagram showing the composition of the pressure-reduction valve concerning this embodiment. It is a flowchart of the gaseous fuel system which concerns on this embodiment. 5 is a flowchart showing a fuel supply operation subroutine of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle 11 Engine room 12 Trunk room 14 Engine 19 Gas fuel injection valve 30 Gas fuel system 31 Main tank 32 Main original valve 33 Supply pipe 35 Shutoff valve 36 Auxiliary pipe 37 Sub tank 38 Sub original valve 39 Fault indication lamp 100 Control unit SW1 Main tank Pressure sensor SW2 Sub tank pressure sensor SW3 Supply pipe pressure sensor SW4 Accelerator opening sensor (an example of operation state detection means)
SW5 engine speed sensor (an example of operating state detection means)

Claims (2)

A main tank for storing gaseous fuel;
A main main valve for opening and closing the main tank;
A supply pipe connected to the main main valve and supplying gaseous fuel in the main tank to a combustion chamber of an engine;
A shutoff valve that is disposed downstream of the main tank of the supply pipe and opens and closes the supply pipe;
A gaseous fuel injection means for injecting gaseous fuel from the supply pipe, provided downstream from the shutoff valve;
In a gaseous fuel system for an engine, comprising at least a control means for controlling an injection timing of the gaseous fuel injection means and an opening / closing timing of the main main valve and the shut-off valve,
An auxiliary pipe connected downstream from the shutoff valve of the supply pipe;
A sub-tank provided at the upstream end of the auxiliary pipe and capable of supplying gaseous fuel to the engine via the auxiliary pipe;
A sub-original valve that opens and closes the sub-tank based on the control of the control means;
An abnormality detection means for detecting an abnormality in the supply pipe and outputting the abnormality to the control means ;
A filling amount detecting means for detecting a filling amount of the gaseous fuel filled in the sub-tank and inputting it to the control means;
An operating state detecting means for detecting the operating state of the engine and outputting it to the control means ;
The control means includes
When it is determined that the supply pipe is normal based on the output of the abnormality detection means, the main original valve and the shutoff valve are opened and the sub original valve is closed to control fuel injection, When it is determined that the supply pipe is abnormal based on the output of the abnormality detection means, fuel injection is controlled by closing the main main valve and the shutoff valve and opening the sub main valve With
Based on the output of the abnormality detection means, it is determined that the supply pipe is normal, the filling amount in the sub tank is less than a predetermined value, and based on the output of the operating state detection means When it is determined that the fuel cut condition is satisfied, a fuel replenishment operation is performed in which the main tank and the sub tank are communicated with each other via the supply pipe . The gaseous fuel system of the engine according to claim 1,
The gas fuel system for an engine, wherein the sub tank, the shutoff valve, and the auxiliary pipe are arranged in an engine room of a vehicle .

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