JPS62153557A - Fuel pressure controller for fuel injector - Google Patents

Abstract

PURPOSE:To vary the fuel pressure according to the environmental temperature by opening and closing an atmosphere opened passage by driving an opening/ closing valve through a shape memory alloy. CONSTITUTION:The suction pipe negative pressure in a surge tank is introduced into an air chamber 5 through a pressure introducing passage 10. A diaphragm 3 shifts to the position where the fuel pressure introduced into a fuel chamber 4 through a fuel passage 11, negative pressure introduced into the pressure chamber 5, and the spring pressure of a control spring 16 are balanced and the pressure of the fuel returned into a fuel tank through a fuel passage 13 is adjusted. When the temperature of fuel becomes high, the spring 6 made of shape memory alloy extends, and an opening/closing valve 7 is put into the lift-up state, and an atmosphere opened passage 9 and the pressure chamber 5 communicate. The pressure in the pressure chamber 5 becomes equal to the atmospheric pressure independently of the pressure in the surge tank, and the fuel pressure is set high a little.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel pressure control device for a fuel injection device used in an internal combustion engine.

[Conventional technology]

If the temperature of the fuel increases in the delivery pipe or fuel injection valve after the internal combustion engine is stopped, there is a risk that a large amount of heparin will be generated.

Conventionally, as a countermeasure to this problem, a vacuum isolating valve (VSV) was placed in the pressure introduction pipe to introduce negative pressure in the intake pipe to the pressure i of the fuel pressure regulator, and VSV was turned on when restarting at a high temperature. However, it is known that the set fuel pressure is raised by about 0.5 kg/cut by forcibly introducing atmospheric air into the pressure chamber to improve restartability and drivability after restart.

Furthermore, in the past, instead of the VSVO, it has been considered to provide a pressure switching valve that switches between the negative pressure in the intake chamber and the atmospheric pressure depending on the ambient temperature (for example, Japanese Utility Model Application Publication No. 75562/1983).

[Problem that the invention seeks to solve]

However, in the conventional method described above, the VS with a complicated structure
Since a V and a pressure switching valve are required, there is a problem in that the cost is high.

Therefore, the present invention aims to make the structure simple and inexpensive.

[Means for solving problems]

Therefore, the present invention provides a fuel pressure regulator that adjusts the pressure of fuel supplied to a fuel injection valve in response to intake pipe negative pressure, and a pressure chamber into which the intake pipe negative pressure of this fuel pressure regulator is introduced. an atmosphere opening passage for opening to the atmosphere; an opening/closing valve for opening and closing the atmosphere opening passage; and an opening/closing valve that opens the opening/closing valve when the ambient temperature is above a predetermined value and when the ambient temperature is below the prescribed value. The present invention provides a fuel pressure control device for a fuel injection device including a shape memory alloy for closing a fuel injection device.

[Effect]

As a result, when the ambient temperature is below a predetermined value, the opening/closing valve is closed by the shape memory alloy, and the fuel pressure is regulated by the negative pressure in the intake pipe led to the pressure chamber of the fuel pressure regulator.
When the ambient temperature is above a predetermined value, the opening/closing valve is opened by the shape memory alloy, and atmospheric pressure is introduced into the pressure chamber from the atmosphere opening passage to increase the set fuel pressure.

〔Example〕

The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 shows a first embodiment of the present invention. 1 is a fuel chamber housing of the fuel pressure regulator, 2 is a pressure chamber housing, and 3 is a diaphragm; both housings 1. The periphery of diaphragm 2 is caulked to sandwich the periphery of diaphragm 3, and the outside air is drawn into housing 1.
．． 2. Also, make sure that the fuel in the fuel chamber 4 does not enter the pressure chamber 5.
In addition, air in the pressure chamber 5 is prevented from entering the fuel chamber 4. 6 is a helical spring made of a two-way shape memory alloy, one end of which is connected to the pressure chamber housing 2, and the other end of which is connected to the pressure chamber 5.
It is stopped by a seat 8 of an on-off valve 7 located inside.

The opening/closing valve 7 opens and closes an atmosphere opening passage 9 formed integrally with the pressure chamber housing 2 by the expansion and contraction of the shape memory alloy spring 6. The outer end of the atmosphere opening passage 9 is led to an air cleaner (not shown) by a pressure pipe 41 (made of rubber or the like) not shown. Also, pressure chamber 5
The end of the pressure introduction passage 10 provided on the side opposite to the fuel pressure regulator is led by a pressure conduit (not shown) (made of rubber or the like) to a surge tank (not shown) into which intake pipe negative pressure is introduced. The fuel passage 1) whose one end opens into the fuel chamber 4 is connected at the other end to a delivery pipe (not shown) either directly or by a fuel conduit (made of rubber or the like) not shown. The other fuel passage 13 of the fuel chamber 4 is connected to a fuel tank (not shown) from the side opposite to the fuel chamber 4 via a fuel pipe (made of rubber or the like) not shown.

A control spring 16 is inserted between the pressure chamber housing 2 and the diaphragm 3 in a compressed state.

In the above configuration, the engine itself is cold while the engine is warming up, and while the vehicle is running, outside air enters the engine compartment and takes away heat from the engine, so less heat is transferred from the intake manifold to the fuel in the delivery pipe.

Therefore, since the temperature of the fuel in the fuel pressure regulator is low and the temperature of the fuel pressure regulator does not rise, the shape memory alloy spring 6, which is stored to expand when the temperature exceeds a predetermined temperature, is in a contracted state. Therefore, the opening/closing valve 7 is connected to the atmosphere opening passage 9.
The pressure chamber 5 is pressed against the atmosphere opening passage 9 and the pressure chamber 5 is shut off. Therefore, the intake pipe negative pressure in a surge tank (not shown) is introduced into the air chamber 5 of the fuel pressure regulator via the pressure introduction passage 10.

Here, the spring constant of the control spring 16 is determined so that the pressure difference between the pressure chamber 5 and the fuel chamber 4 is set to a predetermined value. Then, the diaphragm 3 is displaced to a position where the pressure of the fuel guided into the fuel chamber 4 by the fuel passage 1), the negative pressure guided into the pressure chamber 5, and the spring pressure of the control spring 16 are balanced. The fuel guided into the fuel chamber 4 from the fuel passage 1) by the displacement is returned into the fuel tank through the other fuel 1irl13, and the fuel pressure is adjusted to a predetermined pressure. On the other hand, in operating conditions such as restarting after a put-soak immediately after high-load driving, engine heat is transferred from the intake manifold delivery pipe to the fuel inside the delivery pipe through heat transfer, and the fuel becomes hot. The heat of the fuel in the pipe is transferred to the fuel pressure regulator,
Since the temperature of the fuel pressure regulator becomes high, the shape memory alloy spring 6 becomes in a pre-memorized and stretched state by exceeding a preset temperature. Therefore, opening and closing
The lube 7 is in a lifted state and communicates between the atmosphere opening passage 9 and the pressure chamber 5. Therefore, the atmosphere is introduced into the pressure chamber 5 of the fuel pressure regulator from the atmosphere opening passage 9, and the pressure becomes a constant value (atmospheric pressure) regardless of the internal pressure of the Taj tank 7, and the fuel pressure is set to be about 0.5 kg/cni higher. Ru.

Therefore, the fuel pressure must be set high (for example, 2.
2 kg/c+a-= 2.7 kg/c), the generation of vapor in the fuel at high temperatures is suppressed, and the vapor content of the fuel is injected through the fuel injection valve, resulting in a lean air-fuel ratio. The amount is corrected appropriately.

In addition, when the engine is left idling after restarting or while the car is running, the heat from the fuel pressure regulator is taken away by the wind from the radiator fan or the wind from the car while the car is running, and the temperature of the fuel pressure regulator gradually decreases. As the shape memory alloy spring 6 deforms, when the temperature drops below a preset temperature, the stretched shape memory alloy spring 6 contracts, and the opening/closing valve 7 lowers.
Block the atmosphere opening passage 9. Then, the pressure chamber 5, which was at atmospheric pressure, opened the pressure introduction passage 1 because the atmosphere opening passage 9 was blocked.
equal to the intake pipe negative pressure in the surge tank introduced by 0, and so that the differential pressure between the pressure chamber 5 and the fuel chamber 4 determined by the preset control spring 16 is constant.
The fuel pressure regulator resumes control and returns to normal.

As in the first embodiment, by arranging the shape memory alloy spring 6 and the opening/closing valve 7 in the pressure chamber 5 of the fuel pressure regulator, the pressure chamber 5 is effectively used as an arrangement space, and the overall You can reduce your size.

FIG. 2 shows a second embodiment of the present invention, in which one end of a temporary spring 6A made of a two-way type shape memory alloy is fixed to the outer wall of the fuel chamber housing 1, and the other end of the plate spring 6A is attached to an opening/closing valve 7. is fixed, and the atmosphere opening passage 9 is opened and closed from the outside by this valve 7. The temperature of the fuel in the fuel chamber 4 is transmitted to the temporary spring 6A via the fuel chamber housing 1, and the fuel is kept at a predetermined level. If the temperature exceeds the specified value, the plate will not ＼
The opening/closing valve 7 is lifted by bending the opening 6A into a pre-memorized shape, thereby opening the atmosphere opening passage 9 to the atmosphere.

FIG. 3 shows a third embodiment of the present invention, in which a T is connected to a pressure air passage 10 for introducing negative pressure in the intake pipe into the pressure chamber 5.
1) are connected, and one side 10a on the input side thereof is connected.
is connected to a surge tank, and the other side is connected to the atmosphere as an atmosphere opening passage 9, which is provided in parallel with the delivery pipe 20, and one end of a temporary spring 6A made of a shape memory alloy is fixed to the outer wall of this delivery vibe 20. The atmosphere opening passage 9 is opened and closed from the outside by a valve 7I.

According to this third embodiment, when the temperature of the shape memory alloy leaf spring 6A increases due to the transfer heat of the fuel temperature from the delivery vibe 20 and exceeds a preset value, the shape memory alloy leaf spring 6A increases in advance. The memorized one-oil state is reached, and the opening/closing valve 7 is lifted, thereby opening the atmosphere opening passage 9.

〔Effect of the invention〕

As described above, in the present invention, by simply opening and closing the atmosphere release passage by driving the opening/closing valve using the shape memory alloy, negative pressure in the intake pipe or atmosphere is introduced into the pressure chamber of the fuel pressure regulator. Therefore, the fuel pressure can be varied according to the ambient temperature without using a VSV or pressure switching valve with a complicated structure, and the structure is simple and can be constructed at low cost.

[Brief explanation of drawings]

1 to 3 are longitudinal sectional views showing first to third embodiments of the apparatus of the present invention. 1.2.3...Fuel chamber configuring the fuel pressure regulator, size = 1.・Year 7'y L, 4-
Material chamber, 5... Pressure chamber, 6.6A... Helical spring and plate spring made of shape memory alloy, 7... Opening/closing valve, 9
...Atmospheric release passage, 10...Pressure introduction passage.

Claims (4)

[Claims] (1) A fuel pressure regulator that adjusts the pressure of fuel supplied to the fuel injection valve in response to intake pipe negative pressure, and a pressure chamber into which the intake pipe negative pressure of this fuel pressure regulator is introduced to the atmosphere. an atmosphere opening passage for opening and closing the atmosphere opening passage; an opening/closing valve for opening and closing the atmosphere opening passage; the opening/closing valve is opened when the ambient temperature is above a predetermined value; and the opening/closing valve is closed when the ambient temperature is below the prescribed value. A fuel pressure control device for a fuel injection device comprising a shape memory alloy. (2) The fuel pressure control device for a fuel injection device according to claim 1, wherein the atmosphere opening passage is formed in the pressure chamber, and the opening/closing valve and the shape memory alloy are arranged in the pressure chamber. (3) The fuel injection device according to claim 1, wherein the atmosphere opening passage is formed in the pressure chamber, and the opening/closing valve and the shape memory alloy are arranged and fixed on an outer wall of the fuel pressure regulator. Fuel pressure control device. (4) The fuel pressure control device for a fuel injection device according to claim 1, wherein the atmosphere opening passage is formed on a pressure introduction passage side for introducing intake pipe negative pressure into the pressure chamber.