JP2003328858A - Lpg injection supply device for engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system for supplying a liquid phase LPG injected by an injection valve to an engine, allowing sure high-temperature restart with the liquid phase LPG by preventing the occurrence of a gas phase LPG due to temperature rise in an engine room after the stop of the engine. <P>SOLUTION: Shut-off valves 5, 8 are provided in a supply pipeline 2 via which the liquid phase LPG pressurized by a pump 3 is fed to the injection valve 16 and in a return pipeline 7 via which an extra liquid phase LPG is returned to a fuel tank 1. A subsidiary return pipeline 10 having a high pressure relief valve 11 is provided for bypassing the shut-off valve 8 in the return pipeline 7 and a pressure regulator 9, as required. The shut-off valves 5, 8 are shut off at the stop of the engine and the liquid phase LPG is sealed in a section closed therewith and with the high pressure relief valve 11 to cause pressure rise within a pressure range set by the high pressure relief valve 11 during temperature rise to maintain a liquid phase. Thereby, the injection of the liquid phase LPG sealed at high-temperature restart is allowed. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for supplying LPG, which is a fuel, to an engine by an injection system, and more particularly to a liquid phase LPG alone from an injection valve without mixing the gas phase LPG at the time of high temperature restart. The present invention relates to a device that is injected into a road and supplied to an engine.

[0002]

2. Description of the Related Art In order to increase the output of an engine that uses LPG as a fuel, it is necessary to inject it into an intake pipe using an injection valve in a high pressure liquid phase state without vaporizing under reduced pressure to supply the engine. It is proposed in Japanese Patent Laid-Open No. 63-16162.

As is well known, liquid-phase LPG has a property of being easily vaporized with an increase in temperature, and a liquid-phase LPG filled in a fuel tank at a pressure corresponding to its saturated vapor pressure is further pumped. Even if measures such as pressurizing and sending to the injection valve or increasing the flow rate to suppress the temperature rise around the injection valve due to engine heat are taken, the LPG piping is especially caused by the temperature rise in the engine room after the engine is stopped. Liquid phase LPG filling the system evaporates and vapor phase LPG
The bubbles and lumps of the above are mixed in the liquid phase LPG, which makes it difficult or impossible to restart the engine at the time of high temperature restart.

Therefore, the injection system of the liquid phase LPG and the gas phase L
A PG injection system is provided, and when it is determined that gas phase LPG is generated in the liquid phase LPG injection system, the use of the liquid phase LPG injection system is stopped and the use of the gas phase LPG injection system is switched to. It has been proposed in JP-A-63-18172, JP-A-11-210557 and the like.

However, such a liquid-phase LPG / vapor-phase LPG selection switching system has a gas-phase LP in addition to two injection systems.
There is a problem that not only the apparatus is remarkably complicated because sensors such as pressure and temperature for determining the occurrence of G are required, but also a different injection control system is required for each injection system.

[0006]

DISCLOSURE OF THE INVENTION In the present invention, when the liquid phase LPG is supplied to the engine by the injection method, the LP is generated by the temperature rise in the engine room after the engine is stopped.
The present invention has been made to solve the above-mentioned problem that vapor phase LPG is generated in the G pipe system, making high temperature restart difficult or impossible. It is an object of the present invention to provide an LPG injection supply device that does not use a gas phase LPG injection system and can reliably restart the engine at a high temperature.

[0007]

In order to solve the above-mentioned problems, the present invention firstly provides a pump and a shut-off valve installed on the downstream side of the pump, in which the supply line for sending the liquid phase LPG of the fuel tank to the injection valve is provided. In addition, the return line for feeding excess liquid phase LPG to the fuel tank has a shutoff valve and a pressure regulator, and two shutoff valves open each line when the engine is running but close when the engine is stopped. Then, the liquid-phase LPG was enclosed in the region closed by these, and each pipe was opened after the engine was restarted.

In order to solve the above-mentioned problems, the present invention secondly comprises a pump and a shut-off valve installed on the downstream side of the pump, in which the supply line for sending the liquid phase LPG of the fuel tank to the injection valve. The return line for feeding the excess liquid phase LPG to the fuel tank has a closing valve and a pressure regulator, and the return line has a secondary return line with a high pressure relief valve for bypassing the on-off valve and the pressure regulator. And two shut-off valves are provided for opening the respective pipelines when the engine is in operation, but closed when the engine is stopped, and in the region closed by these and the high-pressure relief valve.
Was enclosed and operated so as to open each pipeline after the engine was restarted.

Furthermore, in order to solve the above-mentioned problems,
In a third aspect of the present invention, in addition to the first or second aspect of the invention, the pump stops operation after the two stop valves close each pipeline when the engine is stopped, and starts driving the injection valve when the engine is restarted. It was decided to start the operation before.

During normal engine operation, the liquid phase LPG pressurized by the pump fills the piping system and the injection valve. When the engine is stopped, the two shut-off valves close the respective pipelines, so that the liquid phase LPG is sealed in the injection valve and the closed sections on the supply side and the return side thereof. The enclosed liquid phase LPG tries to expand due to the temperature rise in the engine room after the engine is stopped, but the pressure rises sharply due to the equal volume change, and the pressure in the closed section becomes higher than the saturated vapor pressure. Generation of vapor phase LPG is prevented. Therefore, when the engine is restarted, the enclosed liquid phase LPG is injected from the injection valve without accompanying the gas phase LPG, and the purpose of reliably performing the high temperature restart can be achieved.

According to the second aspect of the invention, when the pressure in the closed section rises abnormally, the high pressure relief valve opens and discharges, thereby protecting the pipe and the injection valve.

Here, when the operation of the pump is stopped after the two shut-off valves have closed the respective pipelines, the liquid phase LPG pressurized by the pump is enclosed as it is, so that the generation of the gas phase LPG is further ensured. Can be prevented. In addition, by starting the operation of the pump before the start of driving the injection valve, the liquid phase LPG does not drop below the specified pressure when the two shutoff valves open the respective pipelines, and there is no large pressure fluctuation. Can be supplied to the injection valve and the start can be completed in a stable operating state.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Referring to the drawings, an embodiment of the present invention will be described. A pump is provided in a supply line 2 from a fuel tank 1 formed of a pressure resistant container to an injection valve 16 installed in an intake line 15 of an engine. 3, a shutoff valve 4, a shutoff valve 5 and a pressure sensor 6 are provided in this order. In addition, a shutoff valve 8 is provided in the return line 7 for the excess liquid phase LPG from the injection valve 16 to the fuel tank 1.
And the pressure regulator 9 is provided in order.

Further, the auxiliary return pipe 1 which branches off on the upstream side of the closing valve 8 of the return pipe 7 and joins on the downstream side of the pressure regulator 9
0 is provided, and the high pressure relief valve 1 is provided in the auxiliary return line 10 that bypasses the stop valve 8 and the pressure regulator 9.
1 is provided.

The shutoff valve 4 and the two shutoff valves 5 and 8 are electromagnetically driven, and the pressure regulator 9 regulates the liquid phase LPG injected from the injection valve 16 to a predetermined pressure. The pump 3, the two stop valves 5 and 8, and the injection valve 16 perform predetermined operations in response to signals from the electronic control unit 18, and the shut-off valve 4 operates the pump 3 at the same time when the pump 3 is stopped. Open and close road 2. . Further, the present embodiment shows an example applied to fuel supply of an automobile engine, and in the drawing, two shutoff valves 5, 8, a pressure sensor 6, a pressure regulator 9, and a high pressure relief valve 11 are provided inside an engine room 17. Although installed, the object of the present invention can be achieved if at least two stop valves 5 and 8 and a pressure sensor 6 are installed inside the engine room 17.

At the time of normal starting of the engine, two shut-off valves 5 and 8 are operated by a command from the electronic control unit 18.
Is opened and the pump 3 starts operating,
The liquid phase LPG pressurized by the pump 3 is injected from the injection valve 16 into the intake pipe line 15. The liquid phase LPG is maintained at a predetermined constant pressure set by the pressure regulator 9, and during normal engine operation, the fuel tank 1 is connected to the supply line 2 and the return line 7.
Since they circulate through the pipe lines 2 and 7 and the injection valve 16, the liquid phase LPG is filled in a stable state. The high pressure relief valve 11 is set so as not to be opened by the discharge pressure of the pump 3, and the auxiliary return pipe line 10 is closed during engine operation.

When the engine is stopped, the pump 3
2 is stopped, the two stop valves 5 and 8 are closed, and the injection operation of the injection valve 16 is stopped. These may be simultaneously or almost simultaneously, but in the present embodiment, the two stop valves 5 and 8 are closed after the injection of the liquid phase LPG from the injection valve 16 is stopped, and then the pump 3 is turned on. It is assumed that the electronic control unit 18 issues a command to stop.

In this way, the liquid phase LPG of the pump discharge pressure is placed in the region closed by the two closing valves 5 and 8 and the high pressure relief valve 11 of the supply line 2, the return line 7 and the auxiliary return line 10. Will be filled and filled. In this case, the closing valve 8 of the return conduit 7 is closed, the closing valve 5 of the supply conduit 2 is closed when the pressure detected by the pressure sensor 6 reaches a predetermined value, and then the pump 3 is stopped. Sometimes.

When the temperature inside the engine room 17 rises after the engine is stopped, the enclosed liquid phase LPG is heated and tries to expand. However, the volume of the closed conduit is constant and the pressure rises sharply due to the equal volume change, which suppresses evaporation and maintains the liquid phase. When the pressure exceeds the set pressure of the high pressure relief valve 11, the high pressure relief valve 1
1 is opened to release the high pressure liquid phase LP from the auxiliary return line 10.
G is discharged, and the inside of the closed pipeline is maintained at the pressure set by the high pressure relief valve 11.

That is, the high pressure relief valve 11 works as a safety pressure regulator for protecting the pipe and the injection valve 16 when the engine is stopped, and the pressure regulator 9 in the return line 7 is a normal pressure regulator that works during engine operation. .

When the engine is restarted, first, the high-pressure liquid-phase LPG enclosed is injected from the injection valve 16 and restarted, and after the complete explosion, the two stop valves 5 and 8 are opened and the pump 3 It is possible to shift to normal engine operation by restarting the operation of.

However, in this embodiment, at the time of restarting, the operation of the pump 3 is first restarted, and at the same time, the high-pressure liquid-phase LPG enclosed is injected from the injection valve 16 to restart, and after the complete explosion, two The stop valves 5 and 8 are to be opened. More specifically, the pressure on the upstream side of the shutoff valve 5 of the supply pipeline 2 is restored to the discharge pressure of the pump 3, and the pressure in the closed section does not fall below the specified pressure of the injection valve 16 with the injection. By opening the shut-off valves 5 and 8 at the time of decrease, the rapid pressure fluctuation due to the valve opening is reduced and the gas phase L
Stable injection can be continuously performed without generating PG.

In this case, the pressure in the closed section input to the electronic control unit 18 by the pressure sensor 6 is the liquid phase L.
The engine room 17 is opened by opening the on-off valves 5 and 8 and circulating the liquid phase LPG in the fuel tank 1 by the pump 3 at a stage where there is no concern about evaporation of PG and the pressure is not below the specified pressure of the injection valve 16. Even if the inside is at a high temperature, it is possible to fill the inside of each of the pipelines 2 and 7 and the injection valve 16 with the liquid phase LPG without evaporating.

[0024]

As described above, according to the present invention, the liquid phase L inside the piping system and the injection valve is simple in structure and system.
The PG is prevented from evaporating due to the temperature rise in the engine room after the engine is stopped to generate the gas phase LPG, and the high temperature restart can be surely performed by the liquid phase LPG.

[Brief description of drawings]

FIG. 1 is a layout view showing an embodiment of the present invention.

[Explanation of symbols]

1 fuel tank, 2 supply lines, 3 pumps, 5, 8
Shut-off valve, 7 Return line, 9 Pressure regulator, 10
Auxiliary return line, 11 high pressure relief valve, 16 injection valve, 17
Engine room, 18 electronic control unit,

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiromasa Ohno             3029 Kamiyomi, Atsugi City, Kanagawa Prefecture             In Nikki (72) Inventor Satoshi Tsusaka             3029 Kamiyomi, Atsugi City, Kanagawa Prefecture             In Nikki (72) Inventor Masayoshi Tanuma             3029 Kamiyomi, Atsugi City, Kanagawa Prefecture             In Nikki (72) Inventor Takezo Takigawa             3029 Kamiyomi, Atsugi City, Kanagawa Prefecture             In Nikki (72) Inventor Takeshi Nunokawa             3029 Kamiyomi, Atsugi City, Kanagawa Prefecture             In Nikki (72) Inventor Iwasaki Mafumi             3029 Kamiyomi, Atsugi City, Kanagawa Prefecture             In Nikki

Claims (4)

[Claims] 1. A return line for sending excess liquid phase LPG to the fuel tank, wherein a supply line for sending the liquid phase LPG of the fuel tank to the injection valve comprises a pump and a shutoff valve installed downstream thereof. Includes a shutoff valve and a pressure regulator, and the two shutoff valves open the respective pipelines when the engine is in operation, but close the engine when the engine is stopped, and enclose the liquid phase LPG in the region closed by these. The LPG injection supply device for an engine, wherein the LPG injection supply device for an engine is configured to operate so as to open each of the pipelines after the engine is restarted. 2. A return line for sending excess liquid phase LPG to the fuel tank, wherein a supply line for sending the liquid phase LPG of the fuel tank to the injection valve comprises a pump and a shutoff valve installed downstream thereof. Is provided with a shut-off valve and a pressure regulator, and the return line is provided with a sub-return line having a high-pressure relief valve, bypassing the shut-off valve and the pressure regulator, and the two shut-off valves. Liquid-phase LPG in the region which is opened when the engine is running but closed when the engine is stopped and closed by these and the high-pressure relief valve.
And an LPG injection supply device for an engine, characterized in that the LPG injection supply device operates so as to open each of the pipelines after the engine is restarted. 3. In addition to the LPG injection supply device according to claim 1, the pump stops operation after the two stop valves close the respective pipelines when the engine is stopped, and when the engine is restarted. The LPG injection supply device for an engine, wherein the operation is started before the drive of the injection valve is started. 4. The LP of the engine according to claim 1, wherein the two shutoff valves are installed in portions of the supply line and the return line that extend into the engine room.
G injection supply device.