JP2005344584A - Fuel supply device in liquefied petroleum gas internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decompress residual fuel in a fuel piping part and facilitate maintenance at the time of maintenance such as repair and replacement of components provided in the piping part, and eliminate emissions of the fuel to the atmosphere to improve emissions to the environment. <P>SOLUTION: In this liquefied petroleum gas internal combustion engine 3 injecting liquefied petroleum gas in a liquid phase state, a device for supplying residual fuel inside the liquid phase fuel piping 4, 5, 14 to the internal combustion engine 3 is provided. The device for supplying the residual fuel to the internal combustion engine 3 can be a liquid phase injector 11, a gas phase injector 35 or a canister. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fuel supply device in an internal combustion engine using liquefied petroleum gas as a fuel.

  In an internal combustion engine using liquefied petroleum gas as a fuel, the liquid feed fuel in the fuel tank is boosted by a fuel pump and maintained in a liquid phase state and supplied to a fuel pipe including a delivery pipe. It is designed to be supplied by injection. Therefore, in the liquefied petroleum gas internal combustion engine, there is a period in which the liquid phase fuel in the pressurized state remains in the fuel pipe including the delivery pipe even after the engine is stopped, and the fuel pressure is kept high.

  For this reason, it is difficult to perform maintenance such as repair and replacement of components provided in the fuel pipe and liquid-phase injectors provided in the delivery pipe within the pressure maintaining period.

For this reason, it has been known that a fuel supply system is opened to the atmosphere at the time of maintenance, and the remaining liquid phase fuel is vaporized and released to the atmosphere (see Patent Document 1).
JP-A 61-229966

  In the invention described in Patent Document 1, since liquefied petroleum gas is released to the atmosphere, there is an environmentally undesirable problem.

  Accordingly, the present invention provides a liquefaction that facilitates maintenance of the parts by reducing the pressure in the fuel supply system having the parts to be repaired and replaced at the time of maintenance without releasing the liquefied petroleum gas to the atmosphere. An object of the present invention is to provide a fuel supply device for an oil gas internal combustion engine.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a liquefied petroleum gas internal combustion engine for injecting liquefied petroleum gas fuel in a liquid phase state, and a device for supplying residual fuel in the liquid phase fuel pipe to the internal combustion engine. Is provided.

  In the present invention, when the internal combustion engine is stopped, the fuel remaining in the fuel pipe such as the fuel supply pipe, the delivery pipe, and the fuel return pipe can be supplied to the internal combustion engine and consumed by the internal combustion engine. Therefore, during maintenance such as repair and replacement of the parts provided in the fuel pipe part, the fuel remaining in the pipe part is consumed as described above, so that the inside of the fuel pipe is depressurized and maintenance of the parts is performed. It is easy to carry out and does not release fuel into the atmosphere, so it is good for environmental emissions.

  According to a second aspect of the present invention, in the first aspect of the invention, the residual fuel in the liquid phase fuel pipe is converted into a gas phase and supplied to the internal combustion engine.

  In the present invention, even in a state where the liquid phase fuel pipe is depressurized to become a gas phase fuel, the gas phase fuel can be supplied to the internal combustion engine to exhibit the above-described operation and effect.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the apparatus for supplying fuel to the internal combustion engine is a liquid phase injector.

  In the present invention, the above action and effect can be exhibited using an existing liquid phase injector.

  The invention according to claim 4 is the invention according to claim 2, wherein the apparatus for supplying fuel to the internal combustion engine is a gas phase injector.

  In this invention, the effect | action and effect similar to invention of the said Claim 2 can be exhibited.

  The invention according to claim 5 is the invention according to claim 2, wherein the device for supplying fuel to the internal combustion engine is a canister.

  In the present invention, the remaining vapor phase fuel is once adsorbed and collected by the canister, and the collected fuel can be used for the next operation.

  According to a sixth aspect of the present invention, there is provided a liquefied petroleum gas internal combustion engine that injects a liquefied petroleum gas fuel in a liquid phase state, a depressurizing unit that depressurizes a predetermined section of the liquid phase fuel pipe, and the depressurized predetermined gas Means for closing the section and means for supplying the residual fuel in the piping of the depressurized section to the internal combustion engine are provided.

  According to a seventh aspect of the present invention, in the sixth aspect of the present invention, the means for supplying the residual fuel in the pipe of the depressurized section to the internal combustion engine is a liquid phase injector.

  According to an eighth aspect of the present invention, in the sixth aspect of the present invention, the means for supplying the residual fuel in the pipe of the depressurized section to the internal combustion engine is a gas phase injector.

  According to a ninth aspect of the present invention, in a liquefied petroleum gas internal combustion engine that injects liquefied petroleum gas fuel in a liquid phase state, means for closing a predetermined section of the liquid phase fuel pipe, and residual fuel in the blocked section are disposed. A canister for adsorbing and collecting, and means for supplying the fuel adsorbed by the canister to an internal combustion engine are provided.

  In the inventions according to claims 6 to 9, the same actions and effects as described above can be exhibited.

  As described above, according to the present invention, the fuel remaining in the fuel pipe at the time of maintenance is supplied to the internal combustion engine and consumed, thereby reducing the pressure in the fuel pipe and repairing the parts of the pipe section. The replacement can be easily performed, and since the fuel is not released to the atmosphere, it is good for environmental emission.

  According to the second, fourth, and eighth aspects of the invention, the above-described effect can be exhibited even in a state where the liquid phase fuel pipe is further decompressed to become a vapor phase fuel.

  According to invention of Claim 3 and 7, the said effect can be exhibited using the existing liquid phase injector.

  According to the fifth and ninth aspects of the invention, the residual fuel can be used at the next operation without being consumed during maintenance, and the fuel can be effectively used. Furthermore, since it is not necessary to operate the internal combustion engine during maintenance, the power of the internal combustion engine is not required.

  BEST MODE FOR CARRYING OUT THE INVENTION The best mode for carrying out the present invention will be described based on an embodiment shown in the drawings.

  FIG. 1 shows a first embodiment of a fuel supply apparatus. In a fuel tank 1, liquefied petroleum gas (LPG) is stored in a liquid phase (liquid) state and a gas phase (gas) state.

  A fuel pump 2 is provided in the fuel tank 1, and the fuel pump 2 and a delivery pipe 4 of an internal combustion engine 3 (hereinafter also referred to as an engine) are connected by a fuel supply pipe 5. The liquid phase fuel is pumped at a predetermined pressure by the fuel pump 2 and supplied to the delivery pipe 4 in the state of liquid phase fuel.

  The fuel supply pipe 5 is provided with a manual valve 6 located on the upstream side thereof, that is, on the fuel pump 2 side part, and the fuel supply pipe 5 can be opened and closed by the manual valve 6. . A fuel filter 7 is provided in the fuel supply pipe 5 on the downstream side of the manual valve 6. Further, a fuel supply pipe 5 at the downstream side of the fuel filter 7 is provided with a tank side fuel cutoff valve 8, and the tank side fuel cutoff valve 8 is controlled to be opened and closed by an ECU (electronic control unit) 9. It is like that. Further, a fuel supply pipe 5 on the downstream side of the tank side fuel cutoff valve 8 and in the vicinity of the upstream side of the delivery pipe 4 is provided with a fuel cutoff valve (hereinafter referred to as a delivery side fuel cutoff valve) 10 on the delivery pipe side. The delivery side fuel cutoff valve 10 is controlled to be opened and closed by the ECU 9.

  The delivery pipe 4 is provided with a liquid phase injector 11 for injecting liquid phase fuel into the internal combustion engine 3, and the valve opening time is controlled by the ECU 9 to pressurize the liquid phase fuel in the delivery pipe 4. Is supplied by being injected into the internal combustion engine 3 at a set valve opening time.

  The fuel supply pipe 5 between the tank side fuel cutoff valve 8 and the delivery side fuel cutoff valve 10 and the gas phase portion of the fuel tank 1 are communicated with each other by a first bypass passage 12 and the first bypass passage. 12 is provided with a first bypass cutoff valve 13. The first bypass cutoff valve 13 is controlled to be opened and closed by the ECU 9.

  A fuel return pipe 14 is provided on the downstream side of the delivery pipe 4, and the downstream end of the fuel return pipe 14 is open to a gas phase part in the fuel tank 1. The fuel return pipe 14 is provided with a pressure regulator 15 to maintain the pressure of the liquid phase fuel in the delivery pipe 4 at a predetermined high pressure value, and when the pressure becomes higher than the predetermined high pressure value, that is, When surplus fuel is generated, the surplus fuel is returned to the fuel tank 1 side.

  A series of pipes including the fuel supply pipe 5, the delivery pipe 4, and the fuel return pipe 14 are fuel pipes.

  The fuel return pipe 14 is provided with a second bypass passage 16 that bypasses the pressure regulator 15, and a second shut-off valve 17 is provided in the bypass passage 16. The shutoff valve 17 is controlled to be opened and closed by the ECU 9.

  On the upstream side of the manual valve 6 in the fuel supply pipe 5, a first check valve 18 that allows only the flow of liquid-phase fuel to the downstream side is provided, and on the downstream side of the fuel return pipe 14. The part is provided with a second check valve 19 that allows only the downstream flow of fuel.

  In the delivery pipe 4, a delivery internal combustion temperature sensor 20 that detects the temperature of the fuel in the delivery pipe 4 and a delivery internal combustion pressure sensor 21 that detects the fuel pressure in the delivery pipe 4 are provided. A detection signal is input to the ECU 9.

  A tank internal combustion temperature sensor 22 that detects the temperature of the fuel in the fuel tank 1 and a tank internal pressure sensor 23 that detects the pressure of the fuel in the fuel tank 1 are provided in the fuel tank 1. Detection signals from these sensors 22 and 23 are input to the ECU 9.

  The ECU 9 is provided with a maintenance switch 24 that is manually operated during maintenance to input a signal to the ECU 9, and an ECU adjustment mechanism 25 that is operated by an external signal by an operation of an accelerator pedal or the like. The maintenance switch 24 or the adjuster mechanism An external request by 25 can be input to the ECU 9.

  Next, the fuel consumption control in the above configuration will be described with reference to the flowchart shown in FIG.

[First pattern]
When repairing or replacing the parts of the fuel supply piping 5 in the section between the delivery side fuel cutoff valve 10 and the manual valve 6 with the existing liquid phase injector 11 used.
First, a piping section having parts to be repaired and replaced is selected in response to an external request from the maintenance switch 24 or the ECU adjuster mechanism 25 to the ECU 9 when the engine is stopped (step S101).

  For example, when the above selection is made to repair or replace the fuel filter 7 provided in the pipe 5 in the section between the delivery-side fuel cutoff valve 10 and the manual valve 6, first the delivery is performed by a signal from the ECU 9. The side fuel cutoff valve 10 is opened, the tank side fuel cutoff valve 8 is opened, and the first cutoff valve 13 of the first bypass passage 12 is opened (step S102). The second bypass cutoff valve 17 is in a closed state. As a result, the pressure in the delivery pipe 4 and in the fuel supply pipe 5 between the delivery pipe 4 and the manual valve 6 is released to the gas phase portion of the fuel tank 1 through the first bypass passage 12, and the pressure releasing process is performed. As a result of this pressure relief process, the fuel pressure in the piping section is reduced to become gas phase fuel.

  Next, the first bypass cutoff valve 13 of the first bypass passage 12 is closed by a signal from the ECU 9 (step S103).

  Next, the ECU 9 calculates the gas phase fuel injection amount in the liquid phase injector 11 (step S104). This is because the liquid phase injector 11 injects the liquid phase fuel for a set time so as to correspond to the required fuel (A / F) of the engine. Even if the fuel is supplied by opening the valve, the required fuel (A / F) of the engine cannot be met. For this reason, since the liquid phase injector 11 needs to supply gas phase fuel corresponding to the required amount of the engine, the ECU 9 calculates the gas phase fuel injection amount, that is, the valve opening time, and injects a predetermined amount of gas phase fuel.

The calculation of the injection amount of the gas phase fuel will be described with reference to FIG.
In this calculation method, first, the fuel temperature in the tank 1 is detected by the tank internal combustion temperature sensor 22 provided in the fuel tank 1 (step S201), and the tank internal pressure sensor 23 provided in the fuel tank 1 is used. The internal fuel pressure is detected (step S202), and these signals are input to the ECU 9.

  The ECU 9 calculates a propane ratio (mixing ratio of propane fuel and butane fuel) from the input tank internal combustion temperature and tank internal combustion pressure (step S203).

  Next, the fuel temperature in the delivery vip 4 is detected by the delivery internal combustion temperature sensor 20, the fuel temperature is input to the ECU 9, and the gas density correction coefficient is calculated by the ECU 9 based on the propane rate and the delivery internal combustion temperature (step S204). ).

  Further, the fuel pressure in the delivery pipe 4 is detected by the delivery internal pressure sensor 21, and this signal is input to the ECU 9 (step S205). In the ECU 9, a gas fuel pressure correction coefficient is calculated from the delivery internal combustion pressure (step S206).

  Then, the ECU 9 calculates the liquid phase from the basic injection amount (optimum injection amount) (step S207) by the liquid phase injector 11 with the liquid phase fuel set in the ECU 9, the gas density correction coefficient, and the gas fuel pressure correction coefficient. The injection amount (valve opening time) of the gas phase fuel suitable for the required fuel (A / F) to the engine in the injector 11 is calculated (step S208), and the liquid phase injector is calculated with the calculated injection amount (valve opening time). 11 is set to open and close. The valve opening time after this setting is longer than the valve opening time for injecting liquid phase fuel.

Next, in the flowchart of FIG. 2, the manual valve 6 is closed (step S105).
Next, due to engine cranking, gas phase fuel is injected from the liquid phase injector 11 during the calculated valve opening time, and the engine is started at the engine demand (A / F) (step S106).

  After the engine is started, idle rotation or no-load steady rotation of the engine is continued, and gas phase fuel in the delivery pipe 4 and in the fuel supply pipe 5 between the delivery pipe 4 and the manual valve 6 is consumed (step S107).

  When the gas-phase fuel is consumed, the engine is stopped (step S108), and the pressure in the pipe 5 between the delivery pipe 4 and the manual valve 6 decreases.

  Thereafter, the battery terminal is removed (step S109). As a result, the tank-side fuel cutoff valve 8 and the delivery-side fuel cutoff valve 10 in the open state are closed. Thereafter, the parts of the pipe 5 such as the fuel filter 7 are replaced (step S110).

  Since the inside of the pipe 5 is depressurized during this part replacement operation, the part replacement can be easily performed without any trouble, and the fuel in the pipe is not released to the atmosphere.

  Then, after this part replacement work is completed, the battery terminal is attached (step S111), and then the manual valve 6 is opened (step S112), and the work is finished (step S113).

[Second pattern]
Repairing parts in the section between the pressure regulator 15 and the delivery side fuel cutoff valve 10, for example, the liquid phase injector 11, the delivery internal combustion temperature sensor 20, and the delivery internal combustion pressure sensor 21 in FIG. When replacing.
First, when the engine is stopped, a piping section having parts to be repaired or replaced is selected according to an external request from the maintenance switch 4 or the ECU adjuster mechanism 25 to the ECU 9 (step S101).

  For example, when the liquid phase injector 11, the delivery internal combustion temperature sensor 20, and the delivery internal combustion pressure sensor 21 are selected to be repaired, first, the delivery side fuel cutoff valve 10 is opened by a signal from the ECU 9, and the tank side fuel cutoff is performed. The valve 8 is opened and the first bypass cutoff valve 13 is opened (step S115). The second bypass cutoff valve 17 is in a closed state. As a result, in the same manner as described above, the depressurization process is performed in the delivery pipe 4 and in the fuel supply pipe 5 in the section between the delivery pipe 4 and the manual valve 6 to reduce the fuel pressure, and in the delivery pipe 4 and the above section. The inside of the pipe becomes gas phase fuel.

  Next, the delivery side fuel cutoff valve 10 is closed by the signal from the ECU 9, the tank side fuel cutoff valve 8 is closed, and the first bypass cutoff valve 13 is closed (step S116).

  Thereafter, similarly to the first pattern, the processing from step S104 to step S113 is performed.

  In this process, since the delivery pipe 4 is depressurized in step S110, for example, the liquid phase injector 11, the delivery internal combustion temperature sensor 20, and the delivery internal combustion pressure sensor 21 can be repaired and replaced without any trouble. The fuel in the pipe is not released to the atmosphere.

[Third pattern]
When repairing or replacing a part in the section between the pressure regulator 15 and the second check valve 19, for example, the pressure regulator 15, using the existing liquid phase injector.
First, when the engine is stopped, a piping section having parts to be repaired or replaced is selected according to an external request from the maintenance switch 24 or the ECU adjuster mechanism 25 to the ECU 9 (step S101).

  For example, when the pressure regulator 15 is selected to be repaired, first, the delivery side fuel cutoff valve 10 is opened by the signal from the ECU 9, the tank side fuel cutoff valve 8 is opened, and the first bypass cutoff valve is opened. 13 is opened, and the second bypass cutoff valve 17 is opened (step S215).

  As a result, all the piping parts including the delivery pipe 4 are depressurized to reduce the fuel pressure, and the pressure regulator 15 part and the fuel return pipe 14 in the section become gas-phase fuel.

  Next, the delivery side fuel cutoff valve 10 is closed by the signal from the ECU 9, the tank side fuel cutoff valve 8 is closed, and the first bypass cutoff valve 13 is closed (step S216).

  Thereafter, similarly to the first pattern, the processing from step S104 to step S113 is performed.

  In this step, in step S110, since the pressure inside the fuel return pipe 14 is released, for example, the pressure regulator 15 can be repaired and replaced without any trouble, and the fuel in the pipe is not released to the atmosphere.

  FIG. 4 shows a second embodiment of the fuel supply apparatus, in which the vapor phase injector of the retrofit kit can be used in the apparatus of the first embodiment shown in FIG.

  In FIG. 4, the fuel supply piping 5 in the section between the tank side fuel cutoff valve 8 and the delivery side fuel cutoff valve 10 is provided with a first fuel drain port 30 whose port portion is normally closed. The fuel supply pipe 5 in the section between the delivery pipe 4 and the delivery pipe 4 is provided with a second fuel drain port 31 whose port portion is normally closed, and the fuel return pipe in the section between the pressure regulator 15 and the second check valve 19. 14 is provided with a third fuel drain port 32 whose port portion is normally closed. These fuel drain ports 30, 31 and 32 are opened by connecting a hose described later.

  In the embodiment shown in FIG. 4, the second bypass passage 16 and the second shut-off valve 17 shown in FIG. 1 are not provided.

  Furthermore. A surge tank 33 that supplies air sucked from an air cleaner (not shown) to an intake manifold of the engine is provided with a suction port 34 whose port portion is normally closed. The port 34 is opened by connecting a hose described later.

  Further, in this embodiment, one gas phase injector 35 attached at the time of maintenance, that is, a retrofit is used, and the gas phase injector 35 is provided with an inflow side hose 36 and an outflow side hose 37. Yes.

  Since the other structure is the same as the structure shown in FIG.

  Next, the fuel consumption control in the structure shown in FIG. 4 will be described with reference to the flowchart shown in FIG.

[Fourth pattern]
When repairing or replacing the parts of the fuel supply pipe 5 in the section between the delivery side fuel cutoff valve 10 and the manual valve 6.
First, when the engine is stopped, a piping section having parts to be repaired and replaced is selected according to an external request from the maintenance switch 24 or the ECU adjuster mechanism 25 to the ECU 9 (step S301).

  For example, when the above selection is made to repair and replace the fuel filter 7 provided in the pipe 5 in the section between the delivery side fuel cutoff valve 10 and the manual valve 6, first, the tank is The side fuel cutoff valve 8 is opened, and the first bypass cutoff valve 13 is opened (step S302). The delivery side fuel cutoff valve 10 is closed. As described above, the first bypass passage 12 performs the depressurization process in the pipe 5 in the section between the delivery side fuel cutoff valve 10 and the manual valve 6 to reduce the fuel pressure, and this section becomes the gas phase fuel. .

  Next, the first bypass shut-off valve 13 is closed by a signal from the ECU 9 (step S303).

  Next, the ECU 9 changes the one-cylinder injection method designated from the plurality of cylinders from the multi-point injector method to the single-point injector method. Further, similarly to step S104 in FIG. 2, the ECU 9 calculates the injection amount in the gas phase fuel by the calculation method shown in FIG. 3 (step S304).

  In addition, the inflow side hose 36 of one gas phase injector 35 prepared as a retrofit kit is connected to the first fuel drain port 30, and the outflow side hose 37 of the gas phase injector 35 is connected to the intake port 34 of the surge tank 33. Connecting. Both ports 30 and 34 are opened by connecting a hose. Further, the wiring connector from the ECU 9 of one liquid phase injector 11 designated from the plurality of liquid phase injectors 11 is connected to the one gas phase injector 35 (step S305).

Next, the processing from step S105 to step S113 shown in FIG. 2 is performed.
In the fourth pattern, in step S106 and step S107, the gas phase fuel in the fuel supply pipe 5 in the section between the delivery side fuel cutoff valve 10 and the manual valve 6 flows from the first fuel drain port 30 to the inflow side hose. 36 is led to the gas phase injector 35, and is ejected from the gas phase injector 35 into the surge tank 33 by the ejection amount (valve opening time) calculated by the ECU 9, and is supplied from the surge tank 33 to the engine and consumed.

  In this process, in step S110, the fuel supply pipe 5 is depressurized, so that the parts of the fuel filter 7 can be repaired and replaced without any trouble, and the fuel in the pipe is not released to the atmosphere.

[Fifth pattern]
When repairing or replacing the parts of the piping section in the section between the pressure regulator 15 and the delivery side fuel cutoff valve 10, for example, the liquid phase injector 11, the delivery internal combustion temperature sensor 20, and the delivery internal combustion pressure sensor 21.
First, when the engine is stopped, a piping section having parts to be repaired and replaced is selected in accordance with an external request from the maintenance switch 24 or the ECU adjuster mechanism 25 to the ECU 9 as in the fourth pattern (step S301).

  When the selection is made, the delivery side fuel cutoff valve 10 is opened by the signal from the ECU 9, the tank side fuel cutoff valve 8 is opened, and the first bypass cutoff valve 13 is opened (step S306). . As a result, the depressurizing process in the piping in the section between the pressure regulator 15 and the delivery side fuel cutoff valve 10 is performed, the fuel pressure is lowered, and the inside of this section becomes the gas phase fuel.

  Next, the delivery side fuel cutoff valve 10 is closed by a signal from the ECU 9, the tank side fuel cutoff valve 9 is closed, and the first bypass cutoff valve 13 is closed (step S307).

Next, similarly to the fourth pattern, the same processing as step S304 is performed.
Further, the inflow side hose of the gas phase injector 35 is connected to the second fuel drain port 31 as indicated by reference numeral 36a in FIG. 4 (step S308). The fuel drain port 31 is opened by connecting a hose. The outflow side hose 37 is connected to the surge tank 33.

Next, the processing from step S105 to step S113 shown in FIG. 2 is performed.
In the fifth pattern, in step S106 and step S107, the gas-phase fuel in the delivery pipe 4 and in the fuel return pipe 14 in the section between the delivery pipe 4 and the pressure regulator 15 becomes the second fuel drain port 31. From the gas phase injector 35 into the surge tank 33 with the amount of ejection (valve opening time) calculated by the ECU 9, and supplied from the surge tank 33 to the engine for consumption. Is done.

  In this process, since the delivery pipe is depressurized in step S110, the liquid phase injector 11, the delivery internal combustion temperature sensor 20, and the delivery internal combustion pressure sensor 21 can be repaired and replaced without any trouble. Fuel is not released into the atmosphere.

[Sixth pattern]
When repairing or replacing a part of the fuel return pipe 14 in the section between the second check valve 19 and the pressure regulator 15, for example, the pressure regulator 15.
First, when the engine is stopped, the processes of S301, S306, S307, and S304 are performed in the same manner as the fifth pattern.

  After step S304, the inflow side hose of the gas phase injector 35 is connected to the fuel drain port 32 of FIG. 4 as indicated by reference numeral 36b of FIG. 4 (step S309). The fuel drain port 32 is opened by connecting a hose. The outflow side hose 37 is connected to the surge tank 33.

Next, processing from step S105 to step S108 shown in FIG. 2 is performed.
Through the above processing, in steps S106 and S107, the gas-phase fuel in the fuel return pipe 14 in the section between the second check valve 19 and the pressure regulator 15 flows from the third fuel drain port 32 to the inflow side hose 36b. Through the gas-phase injector 35, and is ejected from the gas-phase injector 35 into the surge tank 33 with the ejection amount (valve opening time) calculated by the ECU 9, supplied from the surge tank 33 to the engine and consumed.

  When the pressure regulator 15 as in the sixth pattern is repaired or replaced, the gas phase fuel remaining in the section between the pressure regulator 15 and the second check valve 19, and the pressure regulator 15 and the delivery side fuel cutoff are cut off. Since it is necessary to remove the gas-phase fuel remaining in the section with the valve 10, the fuel is consumed in the section between the pressure regulator 15 and the second check valve 19 in steps S309 and S104 to S107. Is stopped, the processing from the fifth pattern S308 to step S113 is performed, and the fuel in the section between the pressure regulator 15 and the delivery side fuel cutoff valve 10 is consumed.

  In this process, in step S110, since the pressure in the pipe in which the pressure regulator 15 is arranged is released, the pressure regulator 15 can be repaired and replaced without any trouble, and the fuel in the pipe is not released to the atmosphere. .

  FIG. 6 shows a third embodiment of the fuel supply apparatus. This third embodiment uses the canister of the retrofit kit to adsorb and collect the fuel in the pipe to the canister of the retrofit kit at the time of maintenance. The fuel adsorbed and collected in the canister is purged to the engine and consumed.

  The configuration shown in FIG. 6 includes a surge tank 33 provided with the first fuel drain port 30, the second fuel drain port 31, the third fuel drain port 32 and the suction port 34 shown in FIG.

Note that the first bypass 12 and the first bypass cutoff valve 13 shown in FIG. 4 are not provided.
Furthermore, a canister 40 that is not mounted on a vehicle and is used as a retrofit during maintenance is prepared. The canister 40 has a suction hose 42 attached to its suction side port 41 when fuel is sucked, and the tip of the hose 42 is connected to the first fuel drain port 30 or the second fuel drain port 31 or the third fuel drain port. 32 can be connected. The suction hose 42 is provided with a throttle 43 and a manual open / close valve 44.

The canister 40 is provided with a purge side port 45.
The canister described by reference numeral 40A in FIG. 6 is the same as the canister 40, and the suction hose 42 is removed from the canister 40 that has sucked fuel, and the purge side port 45 of the canister 40 is indicated by reference numeral 40A. A purge hose 46 is connected like a canister, and the tip of the purge hose 46 is connected to the suction port 34 of the surge tank 33. The purging hose 46 is provided with a throttle 47.

  At the time of pressure release in the third embodiment, the gas phase injector 35 of the second embodiment is not used.

  Since the other configuration is the same as the configuration shown in FIG.

Next, fuel consumption control in the configuration of the third embodiment will be described with reference to the flowcharts of FIGS.
FIG. 7 is a flowchart of the fuel adsorption operation to the canister 40.

[Seventh pattern]
When repairing or replacing a part provided in the fuel supply pipe 5 in the section between the delivery side fuel cutoff valve 10 and the manual valve 6, for example, the fuel filter 7.

First, when the engine is stopped, the manual valve 6 is closed (step S401).
Next, a piping section having parts to be repaired and replaced is selected in accordance with an external request from the maintenance switch 24 or the ECU adjuster mechanism 25 to the ECU 9 as in step S101 of FIG. 2 (step S402).

  Next, the tank side fuel cutoff valve 8 is opened by a signal from the ECU 9 (step S403).

  Next, the suction hose 42 with the open / close valve 44 closed is connected to the suction side port 41 of the canister 40, and the tip of the suction hose 42 is connected to the first fuel drain port 30 (step S404). .

  Next, the open / close valve 44 of the suction hose 42 is manually opened (step S405). As a result, the fuel in the fuel supply pipe 5 in the section between the manual valve 6 and the delivery side fuel cutoff valve 10 flows out into the canister 40 due to its fuel pressure, and is adsorbed and collected by the adsorbent in the canister 40. The fuel pressure in the fuel supply pipe 5 is reduced to a pressure that does not hinder the repair and replacement work of the fuel filter 7 and is released (step S406).

Next, the open / close valve 44 of the suction hose 42 is closed (step S407).
Next, the battery terminal is removed (step S408). As a result, the tank side fuel cutoff valve 8 in the open state is closed.

  Next, parts of the fuel supply pipe 5, such as the fuel filter 7, are repaired or replaced (step S409). At this time, since the inside of the pipe is depressurized, the fuel filter 7 can be repaired and replaced without any trouble, and the fuel in the pipe is not released to the atmosphere.

Next, a battery terminal is attached (step S410).
Next, the manual valve 6 is opened (step S411), and the fuel adsorption work to the canister 40 is completed (step S412).

  Next, a purge operation for supplying the adsorbed fuel in the canister 40 to the engine after adsorbing the fuel to the canister 40 as described above will be described with reference to the flowchart shown in FIG.

  First, the suction hose 42 of the canister 40 that has adsorbed and collected the fuel as described above is disconnected from the suction side port 41 and the first fuel drain port 30 of the canister 40. A purge hose 46 is connected to the purge port 45 of the canister 40. The canister in this state is indicated by reference numeral 40A. Then, the tip of the purge hose 46 is connected to the suction port 34 of the surge tank 33 (step S501). This connection opens the suction port 34. The purge hose 46 may be connected to the intake manifold. The purging hose 46 may use the suction hose 42 described above.

  Next, in response to an external request from the maintenance switch 24 or the ECU adjuster mechanism 25 to the ECU 9, the ECU 9 sets the idle rotational speed high so that the fuel is consumed quickly. Further, during operation of the engine, purge fuel purged from the canister 40A is added to the basic fuel that is normally supplied, so that the air-fuel ratio (A / F) is feedback controlled or the learning area is expanded. Then, the injection amount of the basic fuel injected from the liquid phase injector 11 is reduced and set by the ECU 9 so as to conform to the required air-fuel ratio of the engine (step S502).

Next, the engine is cranked and the engine is started (step S503).
After the engine is started, the engine is left at idle rotation or is subjected to no-load steady rotation (step S504). The operating time of the engine is a time for consuming the amount of fuel adsorbed by the canister 40A, and is about 10 minutes. By the operation of the engine, the adsorbed fuel in the canister 40A is sucked out of the purge hose 46 into the surge tank 33 and consumed by the engine.

Then, the engine is stopped. (Step S505).
Next, the learned value in the ECU 9 is cleared by the battery clear or maintenance switch 24 or the ECU adjuster mechanism 25, and normal ECU control is performed (step S506).

[Eighth pattern]
When repairing or replacing the parts of the piping section in the section between the pressure regulator 15 and the delivery side fuel cutoff valve 10, for example, the liquid phase injector 11, the delivery internal combustion temperature sensor 20, and the delivery internal combustion pressure sensor 21.
First, in the flowchart of FIG. 7, when the engine is stopped, the manual valve 6 is closed (step S401) in the same manner as in the seventh pattern, and then an external request from the maintenance switch 24 or the ECU adjuster mechanism 25 to the ECU 9 is made. Thus, a piping section having parts to be repaired and replaced is selected (step S402).

  Next, the tip of the suction hose 42 connected to the suction side port 41 of the canister 40 is connected to the second fuel drain port 31 with the open / close valve 44 closed (step S601).

Next, Steps S405 to S412 similar to those in the seventh pattern are performed. In Step S406, the fuel in the piping section in the section between the pressure regulator 15 and the delivery side fuel cutoff valve 10 is adsorbed and collected by the canister 40. At the same time, the pressure in the pipe is released, and in step S409, the liquid phase injector 11, the delivery internal combustion temperature sensor 20, and the delivery internal combustion pressure sensor 21 are repaired and replaced.
Thereafter, the same purge operation as in steps S501 to S506 in the flowchart shown in FIG. 8 is performed.

[Ninth pattern]
When the fuel return pipe 14 in the section between the second check valve 19 and the pressure regulator 15 has parts to be repaired and replaced, for example, when the pressure regulator 15 is repaired and replaced.

  First, in the flowchart of FIG. 7, as with the seventh pattern, the manual valve 6 is closed (step S401), and then repaired or replaced by an external request from the maintenance switch 24 or the ECU adjuster mechanism 25 to the ECU 9. A piping section having parts is selected (step S402).

  Next, the tip of the suction hose 42 connected to the suction side port 41 of the canister 40 is connected to the third fuel drain port 32 with the open / close valve 44 closed (step S701).

  Next, in steps S405 to S412 similar to the seventh pattern, the fuel in the fuel return pipe 14 in the section between the second check valve 19 and the pressure regulator 15 is adsorbed and collected by the canister 40, and The fuel in the pipe 14 is drained, and parts are repaired or replaced.

  Thereafter, the same purge operation as in steps S501 to S506 in the flowchart shown in FIG. 8 is performed.

When repairing or replacing the pressure regulator 15 as in the ninth pattern.
In this case, since the pressurized fuel remains in the upstream piping portion and the downstream piping portion of the pressure regulator 15, the operation of adsorbing and collecting the fuel in both the piping portions in the canister and the adsorption trapping thereof are performed. An operation to purge the collected fuel is required.

  Therefore, in this case, after performing Step S401, Step S402, Step S601, Step S405 to Step S407 shown in the eighth pattern, Step S402, Step S701, Step S405 to Step S405 of the ninth pattern are performed. The operation of S407 is performed, then the operations of Step S408 to Step S412 are performed, and then the operations of Step S501 to Step S506 of the flowchart shown in FIG. 8 are performed.

  FIG. 9 shows a fourth embodiment of the fuel supply apparatus. In the fourth embodiment, during maintenance, the fuel in the pipe is adsorbed and collected in the canister mounted on the vehicle, and then the canister is installed. The fuel that is adsorbed and collected is purged to the engine and consumed.

  The configuration shown in FIG. 9 uses a canister 50 mounted on a vehicle in place of the canisters 40 and 40A of the retrofit kit in the configuration of the third embodiment shown in the sixth embodiment, and the other configurations are those shown in FIG. Since the configuration is the same as that of Example 3, the same parts as those described above are denoted by the same reference numerals and the description thereof is omitted.

  In the canister 50 according to the fourth embodiment, three suction hoses 52, 53, and 54 are branched and connected to the suction side port 51, and the tip of the first suction hose 52 is connected to the first fuel drain port 30. The tip of the second suction hose 53 is connected to the second fuel drain port 31, and the tip of the third suction hose 54 is connected to the third fuel drain port 32. The first suction hose 52 is provided with a first shut-off valve 55 and a throttle 56, and the second suction hose 53 is provided with a second shut-off valve 57 and a throttle 58, and the third The suction hose 54 is provided with a third shut-off valve 59 and a throttle 60.

  A purge hose 62 is connected to the purge side port 61 of the canister 50, and the tip of the purge hose 62 is connected to the suction port 34 of the surge tank 33. The purge hose 62 is provided with an open / close valve (VSV) 63 that is controlled to open and close by a signal from the ECU 9.

  The opening / closing of the shut-off valves 55, 57, 59 and the opening / closing valve 63 is controlled by the ECU 9, but the wiring is omitted in order to avoid complication of the drawing.

Next, the fuel consumption control in the configuration shown in FIG. 9 will be described with reference to the flowchart shown in FIG.
[Tenth pattern]
When repairing or replacing a part of the fuel supply pipe 5 part in the section between the delivery side fuel cutoff valve 10 and the manual valve 6, for example, the fuel filter 7.

  First, in the flowchart shown in FIG. 10, the manual valve 6 is closed while the engine is stopped (step S801).

  Next, in response to an external request from the maintenance switch 24 or the ECU adjuster mechanism 25 to the ECU 9, a piping section having a part to be repaired or replaced is selected (step S802).

  Next, when the above selection is made, the tank-side fuel cutoff valve 8 is opened by a signal from the ECU 9 (step S803).

  Next, the first shutoff valve 55 is opened by a signal from the ECU 9 (step S804). Note that the second cutoff valve 57 and the third cutoff valve 59 are in a closed state.

  As a result, the fuel in the pipe 5 is adsorbed and collected by the adsorbent in the canister 50 through the first suction hose 52 by the fuel pressure, and the fuel pressure in the pipe 5 is reduced and depressurized. (Step S805).

  Next, the battery terminal is removed (step S806). As a result, the tank-side fuel cutoff valve 8 and the first cutoff valve 55 in the open state are closed.

  Then, repair or replacement of a part, for example, the fuel filter 7 is performed (step S807). At this time, since the pressure in the pipe 5 is released, the fuel filter 7 can be repaired and replaced without any trouble. Also, the fuel in the pipe is not released to the atmosphere.

Next, a battery terminal is attached (step S808).
Then, the manual valve 6 is opened (step S809), and the fuel adsorption operation and the parts replacement to the canister 50 are completed (step S810).

  Next, a purge operation for supplying the adsorbed fuel in the canister 50 to the engine after adsorbing the fuel to the canister 50 as described above will be described with reference to the flowchart shown in FIG.

    First, when the purge mode is selected by an external request from the maintenance switch 24 or the ECU adjuster mechanism 25 to the ECU 9 (step S901), the following steps S902 to S905 are performed.

Next, the engine is cranked and the engine is started (step S902).
Next, the open / close valve 63 provided in the purge hose 62 is opened / closed by duty control to adjust the air-fuel ratio (step S903).

After the engine is started, normal operation is performed (step S904). The operating time of the engine is a time for consuming the amount of fuel adsorbed by the canister 50, and is about 10 minutes. Due to the operation of the engine, the adsorbed fuel in the canister 50 is sucked into the surge tank 33 from the purge hose 62 and consumed by the engine.
Then, the opening / closing operation by duty control of the opening / closing valve 63 is stopped, and the opening / closing valve 63 is closed (step S905).

[Eleventh pattern]
When repairing or replacing the parts of the piping section in the section between the pressure regulator 15 and the delivery side fuel cutoff valve 10, such as the liquid phase injector 11, the delivery internal combustion temperature sensor 20, and the delivery internal combustion pressure sensor 21.

  First, in the flowchart of FIG. 10, when the engine is stopped, the manual valve 6 is closed (step S801) in the same manner as in the tenth pattern, and then according to an external request from the maintenance switch 24 or the ECU adjuster mechanism 25 to the ECU 9. Then, the piping section having the parts to be repaired or replaced is selected (step S802).

  Next, when the above selection is made, the second shutoff valve 57 is opened by a signal from the ECU 9 (step S811). The first cutoff valve 55 and the third cutoff valve 59 are in a closed state.

Next, in steps S805 to S810 similar to the tenth pattern, the fuel in the pipe section in the section between the pressure regulator 15 and the delivery side fuel cutoff valve 10 is adsorbed and collected by the canister 50, and the fuel pressure in the pipe The pressure is released and the liquid phase injector 11, the delivery internal combustion temperature sensor 20, and the delivery internal combustion pressure sensor 21 are repaired and replaced.
Thereafter, the same purge operation as in steps S901 to S905 in the flowchart shown in FIG. 11 is performed.

[Twelfth pattern]
When the fuel return pipe 14 in the section between the second check valve and the pressure regulator 15 has parts to be repaired and replaced, for example, when the pressure regulator 15 is repaired and replaced.

  First, in the flowchart of FIG. 10, as with the tenth pattern, the manual valve 6 is closed (step S801), and then repaired or replaced by an external request from the maintenance switch 24 or the ECU adjuster mechanism 25 to the ECU 9. A piping section having parts is selected (step S802).

  Next, when the above selection is made, the third shutoff 59 is opened by a signal from the ECU 9 (step S812). Note that the first cutoff valve 55 and the second cutoff valve 57 are in a closed state.

  Next, the fuel in the fuel return pipe 14 in the section between the second check valve 19 and the pressure regulator 15 is adsorbed and collected in the canister 50 by the same steps S805 to S810 as in the tenth pattern, and the pipe. The internal fuel pressure is reduced to release the pressure, and the parts in the section between the second check valve 19 and the pressure regulator 15 are repaired and replaced.

  Thereafter, the same purge operation as in steps S901 to S905 in the flowchart shown in FIG. 11 is performed.

When repairing or replacing the pressure regulator 15 as in the twelfth pattern.
In this case, since the pressurized fuel remains in the upstream piping portion and the downstream piping portion of the pressure regulator 15, the operation of causing the canister 50 to adsorb and collect the fuel in both the piping portions, and the adsorption An operation to purge the collected fuel is necessary.

  Therefore, in this case, the operations of Step S801, Step S802, Step S811, and Step S805 shown in the eleventh pattern are performed, and then the operations of Step S802, Step S812, and Step S805 of the twelfth pattern are performed. Thereafter, the operations from step S806 to step S810 are performed, and the operations from step S901 to step S905 in the flowchart shown in FIG. 11 are performed.

1 is a system diagram of a fuel supply device showing Embodiment 1 of the present invention. The flowchart which shows the 1st-3rd pattern by the apparatus of FIG. The figure which shows the injection amount calculation method of gaseous-phase fuel. The system diagram of the fuel supply apparatus which shows Example 2 of this invention. 6 is a flowchart showing fourth to sixth patterns by the apparatus of FIG. The system diagram of the fuel supply apparatus which shows Example 3 of this invention. The flowchart which shows the 7th-9th pattern by the apparatus of FIG. The flowchart which shows purge operation by the apparatus of FIG. The system diagram of the fuel supply apparatus which shows Example 4 of this invention. The flowchart which shows the 10th-12th pattern by the apparatus of FIG. The flowchart which shows purge operation by the apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Internal combustion engine 4 Delivery pipe 5 Fuel supply piping 11 Liquid phase injector 14 Fuel return piping 35 Gas phase injector 40, 40A, 50 Canister

Claims (9)

In a liquefied petroleum gas internal combustion engine for injecting liquefied petroleum gas fuel in a liquid phase state, a fuel supply device for a liquefied petroleum gas internal combustion engine is provided, wherein a device for supplying residual fuel in a liquid phase fuel pipe to the internal combustion engine is provided . The fuel supply apparatus for a liquefied petroleum gas internal combustion engine according to claim 1, wherein the residual fuel in the liquid phase fuel pipe is made into a gas phase and supplied to the internal combustion engine. The fuel supply device for a liquefied petroleum gas internal combustion engine according to claim 1 or 2, wherein the device for supplying the internal combustion engine is a liquid phase injector. 3. The fuel supply apparatus for a liquefied petroleum gas internal combustion engine according to claim 2, wherein the apparatus for supplying the internal combustion engine is a gas phase injector. The fuel supply device for a liquefied petroleum gas internal combustion engine according to claim 2, wherein the device for supplying the internal combustion engine is a canister. In a liquefied petroleum gas internal combustion engine that injects liquefied petroleum gas fuel in a liquid phase state, a depressurizing means for depressurizing a predetermined section of the liquid phase fuel pipe, a means for closing the depressurized predetermined section, and A fuel supply apparatus for a liquefied petroleum gas internal combustion engine, characterized in that means for supplying residual fuel in the pipe of the depressurized section to the internal combustion engine is provided. 7. The fuel supply apparatus for a liquefied petroleum gas internal combustion engine according to claim 6, wherein the means for supplying residual fuel in the piping of the depressurized section to the internal combustion engine is a liquid phase injector. 7. The fuel supply apparatus for a liquefied petroleum gas internal combustion engine according to claim 6, wherein the means for supplying residual fuel in the pipe in the decompressed section to the internal combustion engine is a gas phase injector. In a liquefied petroleum gas internal combustion engine that injects liquefied petroleum gas fuel in a liquid phase state, means for closing a predetermined section of the liquid phase fuel pipe, a canister for adsorbing and collecting residual fuel in the closed section, and A fuel supply apparatus for a liquefied petroleum gas internal combustion engine, comprising means for supplying the fuel adsorbed by the canister to the internal combustion engine.