JPS5852369Y2 - Fuel supply control device for fuel injection engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply control device for a fuel injection engine, and particularly to one that is adapted to deal with air that gets mixed into the Tsuyuel pump due to lack of fuel (gas shortage) in the Tsuyuel tank.

Conventionally, as a fuel supply control device for a fuel injection type engine, a fuel injection nozzle and a diaphragm type fuel pressure regulating valve are provided downstream of a fuel pump, and a negative pressure chamber of the fuel pressure regulating valve is communicated with an intake passage downstream of a throttle valve. When the fuel chamber of the fuel pressure regulating valve is connected to the above-mentioned Tsuyuel pump and at the same time connected to the return path, and the pressure difference between the fuel chamber of the fuel pressure regulating valve and the negative pressure chamber becomes a predetermined value or more, that is, when the fuel pressure becomes a predetermined value or more, By opening the fuel regulating valve and returning the fuel to the Tsuyuel tank via the return path, the fuel pressure between the Tsuyuel pump and the fuel pressure regulating valve is always adjusted and maintained at a constant level, and a constant pressure is always maintained from the fuel injection pump. Types that inject fuel are known.

However, in such a fuel supply control device, if the fuel pump sucks air due to lack of fuel (lack of gas) in the fuel tank and air gets mixed into the pump, the fuel pressure between the fuel pump and the fuel pressure regulating valve is kept constant. In order to maintain the fuel pressure at a constant level, air is confined within the Tsuyuer pump.

As a result, even if an attempt is made to start the engine after replenishing the fuel, the pressure in the discharge chamber of the pump does not rise, making it impossible to pump the fuel, resulting in a problem that starting performance is extremely poor after the engine runs out of gas.

The present invention has been developed in view of these points, and in the fuel supply control device for the fuel injection type engine as described above, when starting the engine, the starter is operating, and even after a certain period of time has elapsed since the start of the starter's operation. We focused on the fact that the failure to start is due to air getting mixed in the Tsuyuel pump.
As a result, a pressure switch is provided that operates when the pressure in the discharge chamber of the Tsuyuel pump is low, and
A timer switch is provided that operates a certain period of time after the start of starter operation when the starter is activated, and when both switches are activated, the fuel pressure regulating valve is opened and the tsuyuel pump communicates with the return path, thereby reducing the air inside the tsuyuel pump. It is an object of the present invention to provide a fuel supply control device for a fuel injection type engine which scavenges air so that it can be started at least during the second cranking, thereby improving the startability after running out of gas.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

In FIG. 1, reference numeral 1 denotes a tsuyuel tank; 2, a tsuyuel pump connected to the tsuyuel tank 1 via a suction passage 3; the pump 2 is rotatably driven by a motor 2b built in a housing 2a; and a discharge chamber 2d formed in the housing 2a and supplied with high-pressure fuel discharged from the rotor 2c.
The fuel sucked from the fuel tank 1 is pumped and discharged from the discharge chamber 2d.

A discharge passage 5 is connected downstream of the twerp pump 2 via a check valve 4, and a fuel injection nozzle 6 and a diaphragm fuel pressure regulating valve 7 are disposed in the discharge passage 5.

The fuel pressure regulating valve 7 has a negative pressure chamber 7b and a fuel chamber 7C separated by a diaphragm 7a, and the negative pressure chamber 7b is connected to the throttle valve 10 of the intake passage 9 via a negative pressure passage 8.
The fuel chamber 7c is connected downstream, while the fuel chamber 7c is connected to the discharge passage 5.
It is connected to the above-mentioned Tsuyuel pump 2 via the above-mentioned Tsuyuel pump 2, and at the same time, it is connected to the Tsuyuel tank 1 via a return path 11.

Further, the diaphragm 7a has a valve body 7 that faces the opening 11a of the return path 11 and opens and closes the opening 11a.
d is mounted and supported, and a spring 7e is installed in the negative pressure chamber 7b to bias the valve body 7d in the closing direction. The opening/closing is controlled by the pressure difference between the diaphragm 7a and the biasing force of the spring 7e, and when the differential pressure is equal to or higher than a set value, the diaphragm 7a is biased upward in the figure against the biasing force of the spring 7e to open the valve body 7d. By this, the fuel chamber 7c is communicated with the return path 11, and the fuel pump 2
While returning the fuel from the tank 1 to the fuel tank 1, when the differential pressure is less than the set value, the diaphragm 7a is pressed downward in the figure by the biasing force of the spring 7e and the valve body 7 is returned.
By closing d, the return passage 11 is closed, so that the fuel pressure in the fuel chamber 7c is always adjusted and maintained at a constant level.

A three-way valve 12 is interposed in the middle of the negative pressure passage 8 in the housing, and the three-way valve 12 has a negative pressure chamber side communication port 12a that communicates with the negative pressure chamber 7b of the fuel pressure regulating valve 7, and a negative pressure chamber side communication port 12a that communicates with the negative pressure chamber 7b of the fuel pressure regulating valve 7; An intake passage side communication port 12b that communicates with the vacuum chamber 13, and a vacuum chamber side communication port 12 that communicates with the vacuum chamber 13 such as a brake master back.
c, and when not in operation, the negative pressure chamber side communication port 12a and the intake passage side communication port 12b communicate with each other, and the vacuum chamber side communication port 12c is closed, and the intake passage 9 is connected to the negative pressure chamber 7b. The intake negative pressure is introduced, and the fuel pressure is adjusted by opening and closing the fuel pressure regulating valve I. During operation, the intake passage side communication port 12b is closed, and the negative pressure chamber side communication port 12a and the vacuum chamber side communication port 12c are closed. The high negative pressure of the vacuum chamber 13 is brought into communication with the negative pressure chamber 7b, and the fuel pressure regulating valve I is forced to open.

On the other hand, 14 is a pressure switch that detects the pressure in the discharge chamber 2d of the above-mentioned Tsuyuel pump 2 and turns ON when the pressure is small.
The relay 15 is connected to an ignition contact 16a of a key switch 16 via a relay coil 15a to form a first excitation circuit 17.

Further, 18 is a timer switch, and the timer switch 18 is composed of a multivibrator 2 (H: a transistor 21 that is turned on by the output signal of the multivibrator 20) which delays the activation signal of the starter 19 for a certain period of time. When the starter 19 is activated, the starter 19 is turned on for a predetermined time after a predetermined time delay from the start of the starter 19's operation.

The timer switch 18 is connected to the starter contact 16 of the key switch 16 via the relay coil 22a of the second relay 22.
b, thereby forming a second excitation circuit 23 in parallel with the starter circuit 24.

Further, 25 is a three-way valve operating circuit which connects the three-way valve 12 and the ignition contact 16a of the key switch 16, and the operating circuit 25 includes the relay contact 15b of the first relay 15 and the second relay 22. relay contact 2
2b are connected in series.

Therefore, when the pressure switch 14 and the timer switch 18 are turned on, the first and second excitation circuits 17.2
3, the relay coils 15a and 22a of the first and second relays 15 and 22 are energized and each relay contact 15 is
b.

By closing 22b, the operating circuit 25 is closed and the three-way valve 12 is operated, and the high negative pressure of the vacuum chamber 13 is introduced into the negative pressure chamber 7b of the fuel pressure regulating valve T. It is configured to open and connect the tsuyuel pump 2 and the return path 11.

Note that 16C is a movable contact of the key switch 16, and the movable contact 16c is connected to the battery 26.

Therefore, in the above-mentioned embodiment, when starting the engine with air mixed in the twerp pump 2 due to lack of gas, etc., the movable contact 16c is connected to both the ignition contact 16a and the starter contact 16b by operating the key switch 16. When cranking is performed, the pressure switch 14 is turned ON due to a pressure drop in the discharge chamber 2d due to air mixing in the Tsuyuel pump 2, and the timer switch 18 is mistakenly turned ON at a certain time after the starter 19 starts operating. As a result, the three-way valve operating circuit 25 is closed and the three-way valve 12 is operated by the operation of the first and second relays 17 and 22.

The operation of this three-way valve 12 causes the negative pressure chamber 7 of the fuel pressure regulating valve 7 to
When the high negative pressure of the vacuum chamber 13 is introduced into b and the fuel pressure regulating valve 7 is opened, the tsuyuel pump 2 is communicated with the return passage 11 via the fuel chamber IC, and as a result, the air in the tsuyuel pump 2 is The air is scavenged into the tsuyuel tank 1 via the return path 11.

After cranking for a certain period of time, the timer switch 18 is turned off as the starter 19 stops operating, so the two-way valve 12 is inactive and the fuel pressure regulating valve 7 is in a closed state.

Then, after scavenging, cranking again, this time,
The pressure in the discharge chamber 2d of the Tsuyuel pump 2 is increased by scavenging the air in the Tsuyuel pump 2, and the fuel is force-fed to the fuel injection nozzle 6, so that the engine can be started easily.

At this time, the pressure switch 14 is in the OFF state due to the rise in pressure in the discharge chamber 2d of the above-mentioned Tsuyuel pump 2, so the three-way valve 12 remains in the inactive state, and the negative pressure chamber 7b of the fuel pressure regulating valve 7 is in the OFF state. The intake negative pressure in the intake passage 9 is introduced, and the fuel pressure regulating valve 7 performs a normal fuel pressure regulating function.

Note that the present invention is not limited to the above-mentioned embodiment, and includes various other modifications. For example, in the above-mentioned embodiment, when both the pressure switch 14 and the timer switch 18 are turned on, the three-way valve is turned on. 12 to forcibly open the fuel pressure regulating valve I due to the high negative pressure in the vacuum chamber 13 \The fuel pressure regulating valve 7 is forcibly opened by other electrical or mechanical means. It's okay.

FIG. 2 shows an example of the modification; the same parts as in FIG. 1 are given the same reference numerals and their explanations are omitted)
27 is an operating rod 7f connected to the valve body 7d of the fuel pressure regulating valve 7.
In the figure, it is a solenoid that operates to pull up the solenoid 27, and the operating circuit 28 of the solenoid 27 includes the ON signal S1 of the pressure switch 14 and the timer switch 18.
A control circuit 29 is provided which is turned on in response to the ON signal S2 of the switch 14. When both switches 14 and 18 are turned on,
By activating the solenoid 27 by turning on the control circuit 29, the valve body 7d is pulled upward through the actuator INF 7t against the biasing force of the spring 7e, thereby opening the fuel pressure regulating valve I. be.

As explained above, according to the present invention, a fuel injection nozzle and a diaphragm type fuel pressure regulating valve are provided downstream of the tsuyuel pump, the negative pressure chamber of the fuel pressure regulating valve is communicated with the intake passage downstream of the throttle valve, and the fuel chamber In a fuel supply control device for a fuel injection type engine, which is connected to the above-mentioned Tsuyuel pump and at the same time connected to the return path, there is provided a pressure switch that operates when the pressure in the discharge chamber of the above-mentioned Tsuyuel pump is small, and a pressure switch that operates when the pressure in the discharge chamber of the said Tsuyuel pump is low, and a pressure switch that is constant from the start of operation of the starter when the starter is activated. A timer switch that operates with a time delay is provided, and when both switches are activated, the fuel pressure regulating valve is opened and the return path is communicated with the Tsuyuel pump, thereby removing air that has entered the Tsuyuel pump due to lack of gas. Since the engine can be swept back when starting the engine and the engine can be started easily during the second cranking, it is possible to improve startability after running out of gas.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the present invention, with FIG. 1 being a general schematic diagram, and FIG. 2 being a schematic diagram of essential parts showing a modification. 1... Tsuyuel tank, 2... Tsuyuel pump, 2d... Discharge chamber, 6... Fuel injection nozzle, 7... Fuel pressure adjustment valve, 7a-...
...Diaphragm, 7b... Negative pressure chamber, 7c...
...Fuel chamber, 9...Intake passage, 10...
... Throttle valve, 11 ... Return path, 12 ... Three-way valve, 13 ... Vacuum chamber, 14 ... Pressure switch, 19 ... ...Starter. 18... Timer switch,

Claims (1)

[Scope of utility model registration request] A fuel injection nozzle and a diaphragm type fuel pressure regulating valve are provided downstream of the Tsuyuel pump, and the negative pressure chamber of the fuel pressure regulating valve is communicated with the intake passage downstream of the throttle valve, while the fuel chamber is connected to the Tsuyuel pump and simultaneously connected to the return passage. A fuel supply control device for a fuel injection engine is provided with a pressure switch that operates when the pressure in the discharge chamber of the tsuyuel pump is low, and a timer switch that operates with a certain period of time delay from the start of operation of the starter when the starter is activated. 1. A fuel supply control device for a fuel injection engine, characterized in that when both switches are operated, the fuel pressure regulating valve is opened and the tsuyuel pump is communicated with a return path.