JPH055249Y2 - - Google Patents

Description

[Detailed explanation of the idea] <Industrial application field> The present invention relates to a fuel supply device for an internal combustion engine.

<Prior art> In a conventional electronically controlled fuel injection internal combustion engine,
A fuel supply device for a fuel injection valve (fuel injector) is configured as shown in FIG. 3, for example (see Japanese Utility Model Application Publication No. 124569/1983).

That is, fuel in a fuel tank 1 is sucked in and discharged by a fuel pump 2 equipped with a check valve and supplied to a fuel injection valve 5 through a fuel supply passage 4 in which a filter 3 is interposed. Excess fuel is transferred from the fuel supply passage 4 downstream of the injection valve 5 to the fuel tank via the fuel return passage 7 via the pressure regulator 6, which opens when the pressure in the passage 4 exceeds the set pressure. By returning to 1, the supply pressure to the fuel injection valve 5 is controlled to be substantially constant. The fuel injection valve 5 opens in response to an actuation signal from a control unit (not shown) that controls the amount of fuel injection in accordance with various operating conditions of the engine, and injects fuel into the intake passage.

By the way, in such a fuel supply system, immediately after the engine stops, the fuel temperature rises due to the heat from the engine body and exceeds the steam generation temperature, so steam is generated and an instantaneous restart (hot restart) occurs. There was a problem with starting performance during tri-start.

That is, if the engine is restarted when the fuel temperature is high, vapor will be generated in the pipes because the fuel pressure is low.

For this reason, conventionally, the pressure regulator 6
, the pressure (intake pipe negative pressure) of the downstream part of the throttle valve in the intake pipe, that is, the part where the fuel injection valve 5 is located, is normally guided to the reference pressure chamber 9 in which the spring 8 is housed, and is supplied to the fuel injection valve 5. The pressure is controlled to be a predetermined differential pressure with respect to the intake pipe negative pressure, and the pressure in the reference pressure chamber 9 is controlled between the intake pipe negative pressure and atmospheric pressure via a three-way solenoid valve 10 as shown in the figure. It detects the fuel temperature or engine wall temperature and controls the intake pipe negative pressure to a higher level during instantaneous restart, thereby crushing and liquefying vapor, suppressing the decrease in fuel injection amount due to vapor generation, and instantly restarting the engine. Improves restartability (see Japanese Patent Application No. 59-67382).

<Problems to be solved by the invention> However, with the device in which the intake pipe negative pressure is introduced into the reference pressure chamber 9 in this way, the fuel pressure can only be increased by about 0.5 to 1.0 Kg/ ^cm2 . Therefore, if the increase in fuel pressure is small and the generation of vapor cannot be reliably prevented, and the temperature in the engine room increases further in the future, it will be necessary to further increase the fuel pressure.

Therefore, in view of the conventional situation, the present invention has a structure in which the fuel pressure can be increased to a higher set pressure when restarting the engine, thereby reliably preventing the generation of vapor. An object of the present invention is to provide a fuel supply device for an internal combustion engine that can reduce pressure variations.

<Means for solving the problem> For this reason, the present invention connects the fuel supply passage from the fuel pump equipped with a check valve that sucks and discharges fuel from the fuel tank to the fuel injection valve with a pressure regulator. In a fuel supply system for an internal combustion engine connected to a fuel return passage to a fuel tank via a an inlet port connected to the fuel supply passage on the fuel injection valve side; an outlet port connected to the fuel supply passage on the pressure regulator side; and a fuel passage connecting the inlet port and the outlet port. , a first valve body that normally opens the fuel passage and closes it when restarting the engine; a communication hole provided in the first valve body and communicating with the fuel passage; and a communication hole provided at the tip of the first valve body. A recess that communicates with the communication hole is normally seated at the bottom of the recess by a spring to close the valve, and when the first valve body is closed, the fuel pressure in the fuel supply passage on the fuel injection valve side is The valve device is configured to include a second valve body that opens when a predetermined value is reached and communicates the communication hole and the outlet port.

<Operation> In such a configuration, the first valve body
When the engine is restarted, the fuel supply passage between the downstream side of the fuel injection valve and the pressure regulator is blocked, so the fuel pressure can be increased to, for example, close to the cut-off pressure of the fuel pump, thereby reducing vapor is crushed and liquefied, improving instantaneous restart performance. Further, the second valve body opens at a fuel pressure slightly lower than the cut-off pressure, for example.
Since the fuel is released to the fuel supply passage on the pressure regulator side, variations in fuel pressure at the time of restarting the engine can be suppressed to a small level.

<Example> Hereinafter, an example of the present invention will be described based on FIGS. 1 and 2.

Note that parts having the same functions as those of the conventional example shown in FIG. 3 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

In FIG. 1, in the fuel supply passage 4 between the downstream side of the fuel injection valve 5 and the pressure regulator 6, there is an electromagnetic on-off valve 11 as a valve device that closes the passage 4 when the engine is restarted. Intervened.

That is, this electromagnetic on-off valve 11 serves as a determination means when restarting the engine, based on a signal from a fuel temperature sensor 12 or a water temperature sensor (not shown) that detects the fuel temperature in the fuel supply passage 4 as shown, for example. and is controlled by the control device 13.

Here, when the structure of this electromagnetic on-off valve 12 is shown in FIG. 2, the first valve body 15 disposed inside the tip of the body 14 connected to the fuel supply passage 4 on the side of the pressure regulator 6 is shown. The seat portion 1 on the distal end surface of the valve body 15 is urged downward by the spring 16 as shown in the figure.
5a is seated on the seat part 17 on the inner end surface of the outlet port 14a of the pressure regulator 6 side connection part at the tip of the body 14, and the valve is closed, and the electromagnetic coil 18
When the iron core 19 is excited by being energized, the valve body 15 is attracted by the iron core 19, and the valve body 15 is lifted to open the valve. A fuel passage 19a that guides fuel to a communication hole 15b provided in the valve body 15 is formed in the iron core 19, and its fuel inlet port 19b is configured as a connection portion with the fuel supply passage 4 on the fuel injection valve 5 side. Then, when the valve is opened by lifting the valve body 15 as described above,
Fuel introduced from the fuel passage 19a of the iron core 19 through the communication hole 15b of the valve body 15 passes through the space around the valve body 15 in the tip of the body 14 to the port 14a of the pressure regulator 6 side connection part. It is starting to reach this point.

The electromagnetic on-off valve 12 configured as described above has the following features:
The check valve 20 is equipped with two examples of check valves that open the port 14a of the pressure regulator 6 side connecting portion communicating with the fuel supply passage 4 at a predetermined pressure. Valve body 2
0a is disposed in a recess 15c provided at the tip of the valve body 15 so as to communicate with the communication hole 15b, and is normally seated at the bottom of the recess 15c by a spring 20b, and is connected to the fuel passage 15b. It is set so as not to communicate with the port 14a of the connection portion on the side of the shear regulator 6.

In such a configuration, the fuel pump 2 with a check valve
The fuel in the fuel tank 1 sucked in and discharged by
The fuel is supplied to the fuel injection valve 5 via the fuel supply passage 4. When the pressure in the fuel supply passage 4 between the fuel pump 2 and the fuel injection valve 5 exceeds the set pressure, the pressure regulator 6 opens and excess fuel passes through the fuel return passage 7. The fuel is returned to the fuel tank 1, and the supply pressure to the fuel injection valve 5 is controlled to be substantially constant.

When the engine is restarted, when the fuel temperature sensor 12 or the like detects this, the valve body 1 is opened by energizing the electromagnetic coil 18 of the electromagnetic on-off valve 11.
When the electromagnetic coil 18 is de-energized, the valve 5 is closed by the force of the spring 16, and the port 14a of the connection portion on the pressure regulator 6 side is closed. As a result, the fuel supply passage 4 between the downstream side of the fuel injection valve 5 and the pressure regulator 6 is closed. As a result of the fuel supply passage 4 being blocked in this way, the fuel pressure in the fuel supply passage 4 increases, and the cut-off pressure of the fuel pump 2 (for example,
4.5-6Kg/cm ² ).

As a result of being able to raise the fuel pressure in the fuel supply passage 4 to near the cut-off pressure of the fuel pump 2, it is possible to effectively crush vapor and reliably prevent its occurrence, which will further increase the engine room temperature in the future. However, it can be fully accommodated.

It should be noted that the pulse width applied to the fuel injector 5 when the engine is restarted is corrected to the injection amount in accordance with the change in fuel pressure.

In addition, the valve body of the check valve 20 provided on the electromagnetic on-off valve 11, i.e., the second valve body 20a, opens at a fuel pressure which is slightly lower than a predetermined combustion pressure, for example the shutoff pressure of the fuel pump 2, to allow the fuel to escape to the fuel supply passage 4 on the pressure regulator 6 side. This makes it possible to implement maximum pressure control of the fuel pressure in the fuel supply passage 4 and to prevent the fuel pressure in the fuel supply passage 4 from increasing excessively, thereby making it possible to keep the variation in fuel pressure when the engine is restarted small.

In particular, according to this configuration, the communication hole 15b provided in the first valve body 15 and communicating with the engine passage 19a
a recess 15c provided at the tip of the first valve body 15 and communicating with the communication hole 15b, and a recess 15c that is normally seated at the bottom of the recess 15c by a spring 20b to close the valve; a second valve body 20a that opens when the fuel injection valve 15 is closed and the fuel pressure in the fuel supply passage 4 on the fuel injection valve 5 side reaches a predetermined value, and communicates the communication hole 15b with the outlet port 14a; , and the check valve 20 is connected to the electromagnetic on-off valve 11.
Since the system is built into the engine, it has the function of closing the fuel supply passage 4 and increasing the fuel pressure to the set value when restarting the engine, and the function of suppressing the variation in fuel pressure when restarting the engine. , can be performed by a single valve device, that is, the electromagnetic on-off valve 11,
Since these functions do not need to be performed by separate valve devices, the number of devices can be reduced and manufacturing costs can be kept low. Further, when the above functions are performed by separate valve devices, the number of pipes increases, but when the above functions are performed by a single electromagnetic on-off valve 11, the number of pipes can be reduced.

Furthermore, in configuring the check valve 20, a unique configuration is adopted in which the above-mentioned communication hole 15b and recess 15c are provided, and the spring 20b and the second valve body 20a are incorporated. A check valve function can be easily added to the system, making it easy to simplify the configuration.
From this point of view as well, manufacturing costs can be kept low.

<Effects of the invention> As explained above, according to the invention, since the fuel supply passage between the downstream side of the fuel injection valve and the pressure regulator is closed when the engine is restarted, for example, The fuel pressure can be increased to near the fuel pump's cut-off pressure, which makes it possible to suppress vapor generation more effectively than before.
In addition to more effectively improving restartability, for example, fuel can be released into the fuel supply passage on the pressure regulator side at a fuel pressure slightly lower than the cut-off pressure, so that when the engine is restarted, It is possible to suppress variations in fuel pressure to a small level, and also to simplify the configuration and reduce the number of devices, which has a great practical effect of keeping manufacturing costs low.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram showing an embodiment of a fuel supply system for an internal combustion engine according to the present invention, Fig. 2 is a sectional view showing the structure of an electromagnetic on-off valve in the same embodiment, and Fig. 3 is a conventional fuel supply system. FIG. 1 is a schematic configuration diagram showing an example of a device. 1...Fuel tank, 2...Fuel pump, 4...
Fuel supply passage, 5... Fuel injection valve, 6... Pressure regulator, 7... Fuel return passage, 11...
... Solenoid on-off valve, 12 ... Fuel temperature sensor, 13 ... Control device, 14a ... Outlet port, 15 ... First valve body, 15b ... Communication hole, 15c ... Recess, 19a
...Fuel passage, 19b...Inlet port, 20...
Check valve, 20a...Second valve body, 20b...
…spring.

Claims (1)

[Scope of utility model registration request] The fuel supply passage from the fuel pump with a check valve that sucks in and discharges fuel from the fuel tank to the fuel injection valve,
In a fuel supply system for an internal combustion engine connected to a fuel return passage to a fuel tank via a pressure regulator, an intervening fuel supply passage is provided between the downstream side of the fuel injection valve and the pressure regulator. The valve device is equipped with an inlet port connected to the fuel supply passage on the fuel injection valve side, an outlet port connected to the fuel supply passage on the pressure regulator side, and an inlet port and an outlet port. a first valve body that normally opens the fuel passage and closes it when the engine is restarted; a communication hole provided in the first valve body that communicates with the fuel passage; A recess provided at the tip and communicating with the communication hole, and the valve is normally closed by being seated at the bottom of the recess by a spring, and when the first valve body is closed, the fuel on the fuel injection valve side is An internal combustion engine characterized by being provided with a valve device including a second valve body that opens when the fuel pressure in the supply passage reaches a predetermined value and communicates the communication hole and the outlet port. fuel supply system.