JP4116510B2 - Engine liquid fuel supply system - Google Patents

Description

  The present invention relates to a device for injecting liquid fuel into an intake pipe from a fuel injection valve and supplying it to an engine, and more particularly to a liquid fuel supply device suitable for use with a fuel that is easily vaporized such as LPG.

  A system in which liquid fuel is metered and injected into an intake pipe by a fuel injection valve and supplied to an engine is well known, and in both gasoline and LPG, a fuel tank pressurizes liquid fuel in a fuel tank and sends it to the fuel injection valve And a return pipe for returning surplus fuel not injected by the fuel injection valve to the supply side.

  FIG. 7 is an arrangement diagram schematically showing an example of the system. The liquid fuel in the fuel tank 81 is pressurized by the fuel pump 82, sent to the fuel gallery 84 by the supply pipe 83, and distributed to the fuel injection valve 85. The surplus fuel that has not been injected is returned to the fuel tank 81 through the return pipe 86 and the fuel injection pressure is adjusted to a predetermined pressure by the pressure regulator 87.

  When the engine 91 to which liquid fuel is supplied by such a system is a prime mover of an automobile, the liquid remaining in the fuel gallery 84, the fuel injection valve 85, etc. when the inside of the engine room 92 becomes hot after the engine stops. In the case of fuel that is heated and easily vaporized, such as LPG, a gas phase is easily generated. When the engine 91 is started in such a state, liquid fuel mixed with a gas phase is injected. Insufficient start or inability to start due to lean mixture. In order to avoid this situation, it is conceivable to operate the fuel pump 82 and replace it with the liquid fuel in the fuel tank 81 before starting, but there is a problem that it takes a long time to start.

  Therefore, in systems using LPG, it is common practice to install shut-off valves 88 and 89 that are closed when the engine 91 is stopped and opened during operation in the supply pipe 83 and the return pipe 86 (patents). Reference 1, 2, 3). These shut-off valves 88 and 89 seal LPG in a region including the fuel gallery 84 that is affected by heat in the engine room 92 while the engine is stopped. The pressure of the sealed LPG increases as the temperature rises. By doing so, the liquid state can be maintained without generating a gas phase, and therefore, high-temperature restart can be ensured. However, the shutoff valves 88 and 89 are opened simultaneously with the start of the operation of the engine 91, and the pressure in the region rapidly decreases to the set pressure of the pressure regulator 87, and the fuel gallery 84 and the fuel injection valve 85 themselves are at a high temperature. As a result, a gas phase is easily generated, which tends to cause inconveniences such as unstable engine operation after starting or engine stall.

  On the other hand, in the system using LPG, the shutoff valve 89 of the return pipe 86 shown in FIG. 7 is moved close to the fuel gallery 84 inlet of the supply pipe 83 as indicated by reference numeral 89A to supply the LPG enclosure area when the engine is stopped. 83 (see Patent Document 4). In this system, LPG is sealed between the shut-off valves 88 and 89A while the engine is stopped, and a high-pressure liquid state is maintained, and when the engine is started, the fuel pump 82 is first operated and the section to the upstream shut-off valve 88 is sealed. The upstream shut-off valve 88 is opened after the pressure equal to that in the region, and the downstream shut-off valve 89A is opened a little later than that to introduce liquid LPG into the fuel gallery 84. However, since the LPG does not return to the fuel tank 81 until the downstream shut-off valve 89A is opened, when the fuel gallery 84 or the fuel injection valve 85 is at a high temperature, the sealed region is opened and the normal fuel injection pressure is obtained. Sometimes the gas phase is generated, causing the same inconvenience as described above that the engine operation after starting becomes unstable or the engine stalls. In addition, in a state where the discharge side is closed, the fuel pump 82 is overloaded, which causes early deterioration of durability.

Depending on the temperature and pressure of the LPG sealed in the region between the two shutoff valves 86 and 89 while the engine is stopped, the engine is started by injecting a separately prepared gas LPG, and during that time, the fuel pump 82 Is operated and the sealed LPG is replaced with the liquid fuel in the fuel tank 81, and then the original injection is performed by the fuel injection valve 85, thereby achieving startability and subsequent operation stability (see Patent Document 3). ). However, this requires a separate container for storing the gas LPG, and requires completely different control systems for the liquid LPG injection and the gas LPG injection, which complicates the entire system.
Microfilm of Japanese Utility Model No. 60-21997 (Japanese Utility Model Application No. 61-138860) Microfilm of Japanese Utility Model No. 60-177417 (Japanese Utility Model Application No. 62-87162) JP 63-18172 A JP 2003-83172 A

  The present invention has been made to solve the above-mentioned problems and inconveniences in a system for injecting liquid fuel into an intake pipe from a fuel injection valve and supplying it to an engine. It is an object of the present invention to make it suitable for a liquid fuel that can easily cope with all conditions of the fuel and the engine and can be compatible with each other, and is particularly easily vaporized.

  As a means for solving the above-mentioned problems and disadvantages, the present invention has a fuel pump and a supply pipe that sends a liquid fuel in a fuel tank to a fuel injection valve, which has a shut-off valve that closes when the engine is stopped and opens during operation. And a main fuel piping system comprising a return pipe for returning surplus fuel that has not been injected by the fuel injection valve to the fuel tank and having a pressure regulator; a sub fuel injection valve and a liquid fuel that is arranged at the front and rear of the auxiliary fuel injection valve in a high pressure state A sub fuel pipe system that bypasses the fuel injection valve and branches from the supply pipe and merges with the return pipe, and a gas phase is generated in the liquid fuel in the main fuel pipe system At this time, the liquid fuel sealed in the auxiliary fuel piping system is injected from the auxiliary fuel injection valve.

  In a normal state, that is, in a temperature range in which the engine periphery does not generate a gas phase in the liquid fuel, a drive signal corresponding to the operating state of the engine or a drive that is corrected according to the state of the liquid fuel and the fuel composition at that time The fuel injection valve is opened and closed by a signal, and the liquid fuel flowing through the main fuel piping system is injected and supplied to the engine. In the meantime, part of the liquid fuel pressurized by the fuel pump is introduced into the auxiliary fuel piping system and sealed in the region between the closing means.

  When the engine stops and its surrounding temperature rises, especially when the engine is an automobile engine, the temperature in the engine room rises, and based on this temperature or the state of the liquid fuel in the main fuel piping system, the main fuel piping Estimate or discriminate whether or not a gas phase is generated in the system. If the gas phase is not generated, start by injecting liquid fuel from the fuel injection valve. The liquid fuel sealed in the region is injected from the auxiliary fuel injection valve and started. Since the liquid fuel sealed in the auxiliary fuel piping system does not generate a gas phase at high pressure and high temperature, the auxiliary fuel is corrected according to the pressure and temperature as necessary, or further corrected according to the fuel composition. By opening and closing the injection valve, the high temperature restart can be reliably performed.

  Since the fuel pump starts operation when the engine is started, the liquid fuel in the main fuel piping system is replaced with the liquid fuel sent from the fuel tank while the liquid fuel in the auxiliary fuel piping system is being injected. When returning to the original fuel supply by the valve, there is no worry that the gas phase is injected to make the engine unstable or cause engine stall.

  However, regardless of the state of the liquid fuel in the main fuel piping system at the time of starting, it can be set so that the auxiliary fuel piping system is always used for starting and supplying fuel for a certain period thereafter. In this case, means for discriminating the state of the liquid fuel in the main fuel piping system, and means for selecting whether the fuel supply at start-up is performed in the main fuel piping system or the auxiliary fuel piping system based on the discrimination result It is unnecessary and the control system is very simple.

  As described above, good high-temperature restartability can be obtained and the subsequent engine operation can be stably performed easily in response to all conditions of the fuel and the engine, and in particular, easily vaporized like LPG. The object of providing a suitable means for the liquid fuel is achieved.

  Here, the closing means installed in the auxiliary fuel piping system is selected from a check valve, a relief valve, and an electromagnetic valve. In particular, the closing means on the upstream side of the auxiliary fuel injection valve is the liquid fuel from the supply pipe. A check valve or a solenoid valve is used to allow only the introduction of the fuel, and the downstream closing means uses a relief valve or a solenoid valve or a combination thereof to discharge the sealed liquid fuel to the return pipe and prevent abnormal pressure rise. It is preferable to achieve the object of the present invention.

  According to the present invention, the auxiliary fuel piping system that encloses the liquid fuel, injects it, and supplies it to the engine is provided in the main fuel piping system that is the original fuel system, and these are selectively used at the time of start-up. Therefore, it is possible to easily cope with all the conditions of the fuel and the engine, inject the liquid fuel without the gas phase even in the high temperature restart, and to start the engine reliably and perform the engine operation stably thereafter. .

  Embodiments of the present invention will be described below with reference to the drawings. In FIGS. 1 to 6 showing different embodiments, liquid fuel in a fuel tank 1 is pressurized by a fuel pump 2 and supplied by a supply pipe 3. The fuel is sent to the fuel gallery 6, from which it is distributed to the fuel injection valves 7 installed in each branch pipe of the intake manifold, and a required flow rate corresponding to the operating state of the engine 11 is injected. Further, surplus fuel that has not been injected by the fuel injection valve 7 is returned to the fuel tank 1 through the return pipe 8.

  Isolation valves 4 and 5 comprising electromagnetic valves are installed at locations near the fuel tank 1 and at the fuel gallery 6 in the supply pipe 3, and these and the fuel pump 2 are opened when the ignition switch is turned on. The electronic control device 10 controls the electronic control device 10 to start the operation and open the valve when it is turned off and stop the operation. The electronic control device 10 opens and closes according to the operating state of the engine 11 detected by an engine coolant temperature sensor, a crank angle sensor, an intake air flow rate sensor, a throttle valve opening sensor, an exhaust oxygen sensor, and the like. This is prepared mainly for the purpose of sending an operation signal to the fuel injection valve 7 and further controlling the ignition timing.

  The return pipe 8 is provided with a pressure regulator 9 for adjusting the fuel injection pressure of the fuel injection valve 7 to a predetermined pressure. Referring to FIG. 1, the pressure regulator 9 has a pressure control chamber 9b and a back pressure chamber 9c defined by a diaphragm 9a. An outlet 9d is connected to the pressure control chamber 9b in conjunction with the diaphragm 9a. A valve body 9e for opening and closing is provided. The back pressure chamber 9c is provided with a pressure adjusting spring 9f and is connected to the downstream side of the outlet 9d of the return pipe 8 by a back pressure passage 9g. The pressure regulator 9 shown in FIGS. 2 to 6 has the same structure as this, and the fuel injection pressure is determined by the pressure of the fuel tank 1 introduced into the back pressure chamber 9c and the spring load of the pressure regulating spring 9f. It is adjusted to a predetermined pressure.

  In each embodiment, the engine 11 is an automobile engine, and the shut-off valve 5 on the downstream side of the supply pipe 3 and the pressure regulator 9 of the return pipe 8 are installed inside the engine room 12.

  The fuel pump 2, the supply pipe 3 having the shut-off valves 4 and 5, the fuel gallery 6 for distributing the liquid fuel to the fuel injection valve 7, and the return pipe 8 having the pressure regulator 9 constitute the main fuel piping system A. However, there is a case where the fuel injection valve 7 is a one-point injection system in which the fuel injection valve 7 is installed upstream of the throttle valve in the intake pipe and does not have a fuel gallery.

  A fuel pipe 14 is provided which branches from a downstream area of the supply pipe 3 from the downstream cutoff valve 5, bypasses the fuel gallery 6, and joins the upstream area of the pressure regulator 9 in the return pipe 8. The fuel pipe 14 has one auxiliary fuel injection valve 15 installed upstream of the throttle valve in the intake pipe and blocking means indicated by reference numerals 31, 32, 33, 34, 35, 36, and 37 provided before and after the auxiliary fuel injection valve 15. The auxiliary fuel injection valve 15 and the fuel pipe 14 having the closing means constitute the auxiliary fuel piping system B. The auxiliary fuel injection valve 15 may be installed for each branch pipe of the intake manifold without using one.

  The fuel pipe 14 in the auxiliary fuel pipe system B is branched from an appropriate position in a section from the fuel pump 2 of the supply pipe 3 to the downstream shut-off valve 5 or returned from the pressure regulator 9 of the return pipe 8 to the fuel tank 1. It can be merged at the right place in the section. However, when the engine room 12 is completely installed as in the illustrated embodiment, the fuel pipe 14 can be shortened in total, and the liquid fuel sealed between the blocking means can be influenced by the external atmospheric temperature. In addition, the object of the present invention can be easily achieved in which only the heat inside the engine room 12 is applied and sealed without generating a gas phase, and high temperature restart using the auxiliary fuel injection valve 15 is ensured. be able to.

  On the other hand, in each embodiment, the liquid fuel to be injected from the fuel injection valve 7 of the main fuel piping system A in the region between the fuel gallery 6 of the return pipe 8 and the pressure regulator 9 and in the vicinity of the fuel gallery 6. A temperature sensor 22 and a pressure sensor 23 for detecting the state of the above are installed, and an electrical signal output from these is input to the electronic control device 10. These sensors 22 and 23 and the state determination circuit provided in the electronic control unit 10 constitute a state determination means 21 for determining whether or not the liquid fuel is generating a gas phase. When it is determined that the gas phase is generated when the engine 11 is started, it is determined that the piping system selection means provided in the electronic control device 10 supplies the liquid fuel of the auxiliary fuel piping system B, and the auxiliary fuel is supplied. The injection valve 15 is opened and closed. Alternatively, when it is determined that no gas phase is generated, the liquid fuel in the main fuel piping system A is supplied, and the fuel injection valve 7 is opened and closed.

  In addition to providing piping system selection data, the state discriminating means 21 detects in real time the state of the liquid fuel, particularly the pressure when the liquid fuel in the main fuel piping system A is injected from the fuel injection valve 7. Thus, the drive signal corresponding to the engine operating state is corrected, and the opening / closing operation of the fuel injection valve 7 is made more accurate, so that the engine required fuel flow rate is accurately injected.

  Further, the fuel pipe 15 of the auxiliary fuel piping system B in the embodiment of FIG. 1 is provided with a temperature sensor 25 and a pressure sensor 26 for detecting the state of the liquid fuel sealed between the two closing means. The electric signal to be output is input to the electronic control device 10. The state determination circuit provided in the sensors 25 and 26 and the electronic control device 10 constitutes the state determination means 24 of the liquid fuel sealed in the auxiliary fuel piping system B. The drive signal corresponding to the engine operating state during the restart and the subsequent short engine operation period is corrected mainly using the detected value of the pressure sensor 26, so that the opening / closing operation of the auxiliary fuel injection valve 15 is more accurate. And The state determination means 24 for correcting the drive signal of the auxiliary fuel injection valve 15 can be included in the auxiliary fuel piping system B in the embodiment of FIGS. 2 to 6, but is not necessarily required.

  Further, in each embodiment, a temperature sensor 28 and a pressure sensor 29 are attached to the fuel tank 1, and the temperature and pressure of the stored liquid fuel are input to the electronic control device 10. The electronic control device 10 stores in advance a vapor pressure diagram corresponding to the fuel composition, and the fuel composition is determined by the input temperature, pressure, and vapor pressure diagram. That is, these sensors 28 and 29 and the vapor pressure diagram constitute the composition calculation means 27 of the liquid fuel to be used, and are particularly useful when using an LPG whose composition is unknown or indefinite. Based on the fuel composition obtained by the composition calculation means 27, the fuel injection valve 7 and the auxiliary fuel injection valve 15 are further opened and closed more appropriately by correcting the drive signal corresponding to the engine operating state. be able to.

  In the present invention, at the time of starting the engine, the liquid fuel sealed in the auxiliary fuel piping system B is injected from the auxiliary fuel injection valve 14 regardless of the state of the liquid fuel in the main fuel piping system A, thereby starting and subsequent short-circuiting. There is a case where fuel is supplied for a certain period of time. In this case, the state determination means 21 and the pipe selection means described above are unnecessary.

  In addition, according to the present invention, it is possible to select the piping system to be used at the time of start-up in cooperation with the piping system selection means without using the state determination means 21 described above. That is, in place of the temperature sensor 22 and the pressure sensor 23, a temperature sensor for detecting the ambient temperature is preferably installed in the engine room 12 in the vicinity of the fuel gallery 6, and if necessary, the fuel composition obtained by the composition calculation means 27. The state of the liquid fuel in the main fuel piping system A is estimated by the electronic control unit 10 based on the ambient temperature detected with reference to the above, and when it is estimated that a gas phase is generated, the auxiliary fuel piping system B is used. It is what you want to do. When it is estimated that the gas phase is not generated, the main fuel piping system A is used. The drive signal of the fuel injection valve 7 at this time depends on the ambient temperature or the fuel pressure estimated by the fuel composition in addition to this. Can be corrected. A state estimation circuit provided in the temperature sensor and the electronic control device 10 constitutes a liquid fuel state estimation means for the main fuel piping system A.

  When the engine 11 is started, the fuel pump 2 sends the liquid fuel in the fuel tank 1 to the supply pipe 3, so that the liquid fuel in the main fuel pipe system A is being injected while the sub fuel pipe system B is performing fuel injection. When the liquid fuel sent from the fuel tank 1 is replaced and the sub fuel injection valve 15 is switched to the fuel injection valve 7, the liquid fuel without the gas phase is injected, and the engine operation can be continued stably.

  Next, the auxiliary fuel piping system B will be described for each of the embodiments shown in FIGS. 1 to 6. FIG. 1 shows that the closing means installed upstream of the auxiliary fuel injection valve 15 in the fuel piping 14 is a check valve 31. The closing means installed on the side is a relief valve 32. The check valve 31 functions to block the flow in the opposite direction while allowing the liquid fuel flowing from the supply pipe 3 to pass therethrough, and the relief valve 32 is sealed in a sealing section 14 </ b> A between the check valve 31 and the check valve 31. When the pressure of the liquid fuel is increased, the liquid fuel of the set pressure or higher is discharged to the return pipe 8 so as to ensure safety.

  A part of the liquid fuel sent from the fuel pump 2 during normal operation of the engine 11 is introduced into the auxiliary fuel piping system B, and only when the pressure on the supply piping 3 side is higher than the pressure in the sealed section 14A. When the valve 31 is opened, liquid fuel having a pressure corresponding to the maximum discharge pressure of the fuel pump 2 is sealed in the sealing section 14A. When the engine 11 stops and the temperature in the engine room 12 rises, in the main fuel piping system A, the section between the shut-off valve 5 and the pressure regulator 9 is set to the pressure regulator 9 so that the gas phase It becomes environment that is easy to generate. However, the liquid fuel in the sealed section 14A becomes high pressure below the set pressure of the relief valve 32 and is sealed while maintaining a liquid state without generating a gas phase, and the liquid fuel without a gas phase is supplied from the auxiliary fuel injection valve 15. Will be injected. The auxiliary fuel injection valve 15 performs fuel injection until a predetermined time elapses from the start, during which the main fuel piping system A is replaced with liquid fuel without a gas phase in the fuel tank 1. When the liquid fuel in the sealed section 14A decreases and the pressure decreases, the check valve 31 opens and the liquid fuel from the fuel tank 1 is introduced.

  In FIG. 2, the closing means installed on the upstream side of the auxiliary fuel injection valve 15 is a check valve 31 similar to FIG. 1, and the closing means installed on the downstream side is an electromagnetic valve 33. The electromagnetic valve 33 is opened and closed by an opening / closing command of the electronic control device 10, and is opened at any time during use of the main fuel piping system A. For example, fuel is supplied by the main fuel piping system A after the engine is started. Then, the valve is opened for a certain period of time to replace the liquid fuel in the auxiliary fuel piping system B, and the others are controlled to be closed. In the present embodiment, even when the liquid fuel pressure in the enclosed section 14 </ b> B detected by the pressure sensor 27 becomes equal to or higher than the set pressure, the electronic control device 10 releases part of the liquid fuel to the return pipe 8. Therefore, safety is achieved by opening the electromagnetic valve 33 placed at the closed position. The other operations are the same as those shown in FIG. 1, and liquid fuel without a gas phase is injected from the auxiliary fuel injection valve 15.

  FIG. 3 shows an electromagnetic valve 34 and a relief valve in which the closing means installed on the upstream side of the auxiliary fuel injection valve 15 is a check valve 31 similar to that in FIGS. 1 and 2, and the closing means installed on the downstream side is arranged in parallel. 35. The electromagnetic valve 34 is opened and closed by an opening / closing command of the electronic control device 10, and is opened at any time during use of the main fuel piping system A. For example, fuel is supplied by the main fuel piping system A after the engine is started. Then, the valve is opened for a certain period of time to replace the liquid fuel in the auxiliary fuel piping system B, and the others are controlled to be closed. When the pressure of the liquid fuel sealed in the sealing section 14 </ b> C between the check valve 31, the electromagnetic valve 34, and the relief valve 35 rises, the relief valve 35 returns liquid fuel equal to or higher than the set pressure to the return line 8. Release and work to be safe. In this embodiment, since the relief valve 35 is used in addition to the electromagnetic valve 34, the number of parts of the auxiliary fuel piping system B is increased. However, the control system of the electromagnetic valve 34 is compared with the electromagnetic valve 33 of FIG. And has the advantage of being easy.

  In the embodiment of FIGS. 1, 2, and 3, when the fuel supply amount by the auxiliary fuel piping system B increases and the fuel pressure in the enclosing sections 14A, 14B, 14C decreases, the check valve 31 opens and the fuel is discharged. The liquid fuel sent from the pump 2 is introduced. As a result, the auxiliary fuel piping system B can be used without worrying about fuel shortage.

  In FIG. 4, the closing means installed on the upstream side of the auxiliary fuel injection valve 15 is the electromagnetic valve 36, and the closing means installed on the downstream side is the relief valve 32. The solenoid valve 36 is opened for a certain period of time after the fuel is supplied by the main fuel piping system A after the engine is started, for example, after the engine is started, and the relief valve of the auxiliary fuel piping system B is used. Opening and closing is controlled by the electronic control device 10 so that the liquid fuel sent from the fuel pump 2 is introduced into the upstream region 32, and the others are closed. When the pressure of the liquid fuel sealed in 14D rises in the sealed section between the relief valve 32 and the solenoid valve 36, the relief valve 32 works to release the liquid fuel above the set pressure to the return pipe 8 for safety.

  FIG. 5 shows electromagnetic valves 36 and 37 as the closing means installed on the upstream side and the downstream side of the auxiliary fuel injection valve 15. The upstream side electromagnetic valve 36 is controlled by the electronic control unit 10 as shown in FIG. Control is performed in the same manner as the valve 36. The downstream solenoid valve 37 opens at the same time or slightly before the upstream solenoid valve 36 opens, and opens before the upstream solenoid valve 36 closes. It is controlled by the electronic control unit 10 so as to be closed except that the liquid fuel in the fuel piping system B is replaced and liquid fuel is secured in the sealed section 14E between the two solenoid valves 36 and 37. Similarly to the solenoid valve 33 in FIG. 2, the downstream solenoid valve 37 is electronically controlled so that a part of the liquid fuel is discharged to the return line 8 when the pressure in the sealing section 14E becomes equal to or higher than the set pressure. It is controlled by the device 10. Further, the two solenoid valves 36 and 37 in the present embodiment are opened when energized and closed when de-energized, and the liquid fuel pressure in the enclosed section 14E is seated on the valve seat when the valve is closed. Applying force in the valve closing direction to the valve body that is closed, so that when the pressure rises, the seating on the valve seat is made strong and liquid fuel is sealed in the sealing section 14E, and fuel is supplied from the auxiliary fuel piping system B. The structure is used to make it work properly.

  In FIG. 6, the closing means installed on the upstream side of the auxiliary fuel injection valve 15 is an electromagnetic valve 36 similar to that in FIGS. 4 and 5, and the closing means installed on the downstream side is arranged in parallel as in FIG. 34 and the relief valve 36, and their functions and actions are basically the same as those in the above-described embodiment. That is, the two solenoid valves 36 and 34 are controlled by the electronic control device 10 so that they open at any time when the main fuel piping system A is injecting liquid fuel, but are closed at other times. Is done. Further, the relief valve 35 returns the liquid fuel above the set pressure to the return line 8 when the pressure of the liquid fuel enclosed in the enclosure section 14F between the solenoid valve 36, the solenoid valve 34, and the relief valve 35 rises. discharge. More specifically, regarding the two solenoid valves 36, 34, the downstream solenoid valve 34 opens at the same time or slightly before the upstream solenoid valve 36 opens, and the upstream solenoid valve 36 Control is performed so that the valve is closed before the valve is closed, the liquid fuel in the auxiliary fuel piping system B is replaced and the liquid fuel in the sealed section 14F is secured, and the others are closed.

  4, 5, and 6, the upstream side solenoid valve 36 is assumed to have a pressure in which the liquid fuel in the sealed sections 14 </ b> D, 14 </ b> E, and 14 </ b> F is injected and decreases, resulting in fuel shortage. When the pressure detected by the sensor 27 is lower than the pressure detected by the pressure sensor 23 of the main fuel piping system A, the electromagnetic valve 36 is opened and liquid fuel sent from the fuel pump 2 is introduced and replenished. In this way, the electronic control device 10 controls the system. As a result, the fuel supply by the auxiliary fuel piping system B can be appropriately performed regardless of the operating state of the engine 11 until the fuel supply is switched to the main fuel piping system A.

  2 and 3, the downstream solenoid valves 33 and 34, the upstream solenoid valve 36 in the embodiment of FIG. 4, the downstream and downstream solenoids in the embodiment of FIG. Regarding the valves 36 and 34, when the pressure of the liquid fuel in the enclosure sections 14B, 14C, 14D, and 14F rises when the valve is closed, similarly to the solenoid valves 36 and 37 in the embodiment of FIG. A structure that acts to increase the valve closing force can be used.

The layout which shows 1st embodiment of this invention. The layout which shows 2nd embodiment of this invention. The layout which shows 3rd embodiment of this invention. The layout which shows 4th Embodiment of this invention. The layout which shows 5th embodiment of this invention. The layout which shows the 6th Embodiment of this invention. The layout which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel tank, 2 Fuel pump, 3 Supply line, 4,5 Shut-off valve, 7 Fuel injection valve, 8 Return line, 9 Pressure regulator, 10 Electronic control apparatus, 11 Engine, 12 Engine room, 14 Fuel piping , 15 Sub fuel injection valve, 21 State determination means, 24 State determination means, 27 Composition calculation means, 31 Check valve, 32, 35 Relief valve, 33, 34, 36, 37 Solenoid valve, A Main fuel piping system, B Secondary fuel piping system

Claims (16)

A fuel pump and a shut-off valve that closes when the engine is stopped and opens when the engine is in operation, has a supply pipe that sends liquid fuel in the fuel tank to the fuel injection valve, and a pressure regulator that was not injected A main fuel piping system comprising return piping for returning surplus fuel to the fuel tank;
A sub fuel piping system having a sub fuel injection valve and a closing means disposed at the front and rear of the sub fuel injection valve for sealing liquid fuel in a high pressure state, bypassing the fuel injection valve and branching from the supply pipe and joining the return pipe When,
When the gas phase is generated in the liquid fuel of the main fuel piping system, the fuel sealed in the auxiliary fuel piping system is injected from the auxiliary fuel injection valve,
A liquid fuel supply device for an engine. The sub fuel pipe system in the liquid fuel supply apparatus according to claim 1 is used instead of the sub fuel pipe system used when a gas phase is generated in the liquid fuel of the main fuel pipe system. The sub-fuel injection valve injects liquid fuel that is sealed so as to start and supply fuel for a certain period of time regardless of the state of the liquid fuel.
A liquid fuel supply device for an engine.   The engine is an automobile engine, the shut-off valve and the pressure regulator are installed in the engine room, and the auxiliary fuel piping system branches from the shut-down downstream side of the supply pipe and is upstream of the pressure regulator of the return pipe. The liquid fuel supply device for an engine according to claim 1 or 2, which is joined.   A state determination unit for liquid fuel in the main fuel piping system, and a piping system selection unit for selecting a fuel supply at start-up based on the determination result. The engine according to claim 1 or 3, wherein when it is determined that a gas phase is generated, the piping system selection means determines to inject the liquid fuel sealed in the auxiliary fuel piping system. Liquid fuel supply device.   A state estimating means for estimating the state of the liquid fuel in the main fuel piping system based on the ambient temperature, and a piping system selecting means for selecting which of the starting fuels is to be supplied based on the estimation result. 2. The piping system selecting means determines to inject the liquid fuel sealed in the sub fuel piping system when the means estimates that a gas phase is generated in the liquid fuel. Or a liquid fuel supply device for an engine according to 3;   A means for determining a state of the liquid fuel in the main fuel piping system, correcting a drive signal according to an engine operating state based on the determination result, and opening and closing the fuel injection valve by the corrected drive signal; The liquid fuel supply device for an engine according to claim 1, 2, 3, or 4.   It comprises a means for determining the state of the liquid fuel sealed in the auxiliary fuel piping system, corrects the drive signal according to the engine operating state based on the determination result, and controls the auxiliary fuel injection valve with the corrected drive signal. 7. The liquid fuel supply device for an engine according to claim 1, wherein the liquid fuel supply device is operated to open and close.   Comprising means for calculating the composition of the liquid fuel, correcting the drive signal according to the engine operating state based on the calculation result, and opening and closing the fuel injection valve and the auxiliary fuel injection valve by the drive signal with this correction 8. The liquid fuel supply device for an engine according to claim 1, 2, 3, 4, 5, 6 or 7.   The blocking means is a check valve that allows only the flow of liquid fuel from the supply pipe, and is installed on the upstream side of the auxiliary fuel injection valve. 4. The liquid fuel supply device for an engine according to claim 1, which is a relief valve that discharges liquid fuel to the return pipe.   The blocking means is a check valve that allows only the flow of liquid fuel from the supply pipe, and is installed on the upstream side of the auxiliary fuel injection valve, and an electromagnetic valve that is installed on the downstream side. The solenoid valve opens at an arbitrary time when the main fuel piping system is injecting liquid fuel, but is closed at other times, and is higher than the set pressure even when placed in the valve open position. The liquid fuel supply device for an engine according to claim 1, 2 or 3, wherein the liquid fuel is controlled so as to be opened to release the liquid fuel to the return pipe.   The blocking means is a check valve that allows only the flow of liquid fuel from the supply pipe, which is installed upstream of the auxiliary fuel injection valve, and is installed in parallel with that which is installed downstream. A solenoid valve and a relief valve, wherein the solenoid valve is controlled to open at any time when the main fuel piping system is injecting liquid fuel, but is otherwise closed; 4. The liquid fuel supply device for an engine according to claim 1, wherein the relief valve discharges liquid fuel having a pressure equal to or higher than a set pressure to the return pipe.   The closing means is a solenoid valve that is installed upstream of the auxiliary fuel injection valve, and a relief valve that is installed downstream of the auxiliary fuel injection valve, wherein the main fuel piping system is liquid. The valve is controlled to open during an arbitrary period when fuel is being injected but is otherwise closed, and the relief valve discharges liquid fuel at a set pressure or higher to the return pipe. 4. The liquid fuel supply device for an engine according to claim 1, 2, or 3.   The closing means is an electromagnetic valve installed on both the upstream side and the downstream side of the auxiliary fuel injection valve, and the upstream side solenoid valve is used when the main fuel piping system is injecting liquid fuel. It is assumed that the valve is controlled to open at an arbitrary time, but is closed thereafter, and the downstream solenoid valve is operated simultaneously with or slightly before the upstream solenoid valve is opened. 4. The liquid fuel supply device for an engine according to claim 1, wherein the liquid fuel supply device is controlled so that the valve is opened and closed before the valve is closed and thereafter closed.   The closing means is an electromagnetic valve installed upstream of the auxiliary fuel injection valve, and an electromagnetic valve and relief valve arranged downstream are arranged in parallel. The valve is controlled to open at any time when the main fuel piping system is injecting liquid fuel, but is otherwise closed, and the relief valve is a liquid that exceeds the set pressure. 4. The liquid fuel supply device for an engine according to claim 1, wherein fuel is discharged to the return pipe.   The solenoid valve installed on the upstream side is opened when the pressure of the liquid fuel in the sealed section between the closing means on the downstream side decreases while the sub fuel piping system injects the liquid fuel. The liquid fuel supply device for an engine according to claim 12, 13 or 14, wherein the liquid fuel sent from the fuel pump is controlled to be introduced and replenished into the sealed section. The electromagnetic valve constituting the closing means has a structure in which the liquid fuel pressure in the sealed section between the upstream and downstream closing means acts as a valve closing force on the valve body when the valve is closed. 12. A liquid fuel supply device for an engine according to 12, 13, or 14.

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