JPS58144661A - Fuel-pressure controlling apparatus for fuel supplying apparatus - Google Patents

Abstract

PURPOSE:To enable to absorb fluctuation of fuel pressure with high sensitivity, by causing reciprocal movement of a movable member of a pressure regulating valve by an output shaft of a linear motor that is driven by current supplied from an electronic control unit, and thereby moving a valve element of said valve toward and away from a valve seat. CONSTITUTION:After fuel in a tank 7 is pressurized by a pump 8 and fuel pressure is controlled to a prescribed pressure by a pressure regulating valve 9, fuel is injected from an injection valve 10 into an intake passage 11 and mixed with intake air. Then, the air-fuel mixture is supplied to an engine 4. The pressure regulating valve 9 is designed such that a valve body 23 projected from the center of a movable member 22 is urged onto a valve seat 21 by the force of a spring 26. Here, arrangement is such that, when positive current is applied to an output shaft 28 of a linear motor 27, the shaft 28 is moved forward and urges the movable member 22 toward a valve chamber 20. Further, the period and the rate of pressure change caused by the opening and closing of the injection valve 10 are applied to an electronic control unit 14. At the time of pressure rise, for instance, fuel is released to the tank 7 by feeding reverse current to the motor 27 and thereby detaching the valve body 23 from the valve seat 21.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel pressure control device in a feedback type fuel supply device that injects fuel into an intake passage, mixes it with intake air, and supplies the mixture to an engine.

Information such as suction negative pressure, throttle valve opening, and exhaust composition is given as input signals to the electronic control device.

In this method, the fuel is controlled so as to output a flow to drive the injector and obtain a mixture with an appropriate air/air ratio.The fuel pressurized by the fuel pump is adjusted to a constant pressure by the pressure regulating valve, and then injected. Injected from the valve. The pressure regulating valve has a valve body installed on a movable member such as a diaphragm that responds to fuel pressure, a valve seat equipped with a return passage (Ic) that reaches the fuel tank,
It is equipped with a spring that acts on a movable member in the direction of seating the valve body on the valve seat, and when the fuel pressure sent from the fuel pump to the injection valve overcomes the spring load, the valve body is separated from the valve seat and fuel is released. . Therefore, when the spring load is set, the valve opens and fuel is released when the fuel pressure exceeds a certain level. However, in reality, the injection valve is driven by a solenoid and repeats opening and closing in an extremely short period of time, so pressure fluctuations are repeated in short cycles in the fuel passage from the fuel pump to the injection valve, causing a phenomenon similar to a mallet effect. ~・ru. This short-period pressure fluctuation accompanying the opening and closing of the injection valve generates a high enough pressure to open the pressure regulating valve, which stabilizes the fuel pressure and increases the capacity of the valve chamber of the N companding valve. Although it is possible to absorb pressure fluctuations and stabilize the fuel pressure to a considerable extent, it is disadvantageous because the entire pressure regulating valve becomes larger.

The present invention was invented with the main purpose of solving these problems, and by applying the thrust of a linear motor to the valve body of the pressure regulating valve, it can open and close by closely following pressure fluctuations. It is possible to stabilize the fuel pressure by performing this, and furthermore, it is possible to change the set load arbitrarily.

Embodiments of the present invention will be described below with reference to the drawings. In figure 1, l is an air cleaner, 2 is a throttle body, 3 is an intake manifold, 4 is an engine, 5 is an exhaust manifold, and 6 is an air cleaner.
is a throttle valve.

7 is a fuel tank, 8 is a fuel pump, 9 is a split compressor, ] 0 is an electromagnetically driven injection valve, which is located upstream of the throttle valve 6 in the intake passage 11 that reaches the inlet of the engine 4, including the air cleaner l.
An injection valve lO is installed at M. The fuel is sucked out from the fuel tank 7 and pressurized by the fuel pump 8, passes through the pressure regulating valve 9, is regulated to a constant pressure, reaches the injection valve 0, is injected into the intake passage 11, mixes with the intake air, and is pumped into the engine 4. sent to.

The fuel pressure at the inlet of the injection valve 10 is detected, and the air cleaner l
12. Fuel pressure detector for comparison with air pressure near the outlet of the fuel pressure sensor 12.
In addition to the intake pressure detector 13 of the intake manifold 3, the engine speed, engine temperature, intake air temperature, throttle valve opening,
Input signals from a detector such as exhaust composition, an ignition switch, and an air conditioner operating switch are provided to the electronic control device 14 as information on engine operation.

A driving current is output from the electronic discount device 1 to the solenoid 16 for driving the injection valve.

The pressure regulating valve 9 includes a valve body 19 inserted into a fuel passage 17 leading from the fuel tank 7 to the injection 4P10, and a valve chamber 20 therein.
The movable member 22 has a valve seat 21 provided at the entrance of the return passage 18 and a spherical valve body 23 fixedly protruding from the center of a movable member 22 consisting of a diaphragm. A coiled spring 26 inserted between the valve element 23 and a spring receiver 25 built into the atmospheric chamber 24 on the opposite side acts to seat the valve element 23 on the valve seat 21. The spring bearing 251C linear motor 27 of the atmospheric chamber 24 is fixed to be located on the center line of the valve seat 21 and the valve body 23, and the tip end surface of the output shaft 28 is in contact with the center of the flexible member 22, and further The position of the spring receiver 25 is adjustable by an r-knot screw 29.

The linear motor 27 generates a thrust proportional to the current value, and the output shaft 28 advances when a positive current is applied and pushes the movable member 22 toward the valve chamber 20, and when the current is cut off, the output shaft 28 moves forward and pushes the movable member 22 toward the valve chamber 20. It is in a free state and moves backward when a current in the opposite direction is applied, which is also supplied to the electronic control unit 14.

The fuel pressure at the inlet of the injection valve 10 is continuously detected by the fuel pressure detector 13, and the cycle and change value of pressure fluctuations that occur when the injection valve 10 opens and closes are input to the electronic control device 14, and when the pressure increases, the pressure changes linearly. Supplying current in the opposite direction to the motor 427 or cutting off the current to move the movable member 22 into the atmosphere 2 with fuel pressure.
4, the valve body 23 is separated from the valve part 21, and the fuel is discharged into the fuel tank 7 via the return passage 8. When the pressure decreases, a positive current is supplied to the linear motor 27 to seat the valve body 23 on the valve seat 2J.

The fuel pump 8 also works in a similar manner to keep the fuel pressure constant even when the pressure of the fuel being sent varies. Also,
By changing the current value supplied to the linear motor 27, the output shaft 2
When the thrust of the fuel injection valve 8 is increased, the closing force of the pressure regulating valve 9 is increased, the fuel pressure sent to the injection valve 10 is increased, and the fuel injection amount is increased. Therefore, by increasing or decreasing the thrust of the output shaft 28 from a set value.

It injects and supplies a large amount of fuel required during acceleration, high speed, high load, etc. without significantly changing the opening/closing time ratio of the injection valve IO per unit time.

Alternatively, a small amount of fuel can be injected and supplied when the vehicle is idling or at low speed.

Furthermore, depending on the composition of the exhaust gas and other engine operation information, not only the opening/closing time ratio of the injection valve lO but also the pressure regulating valve 9 can be determined.
Needless to say, control is performed to supply the engine with a mixture having an appropriate air-fuel ratio by changing the valve-closing force of the engine.

Incidentally, the fuel pressure detector 12 may detect the absolute pressure of the fuel without detecting the differential pressure between the air pressure near the outlet of the air cleaner 1 and the fuel pressure. I cut it. The pressure regulating valve 9 may be provided in the middle of the return passage 18, and the spring 26 that closes the valve is preferably set so that the spring load is zero when the valve is closed. The pressure regulating valve 9 may be opened and closed only by the difference between the pressure and the thrust of the linear Φ motor 27. Face Matata.

Since the opening/closing stroke of the pressure regulating valve 9 is extremely small, the moving distance of the output shaft 28 of the linear pot motor 27 is also extremely short, and it is possible to optically follow fluctuations in fuel pressure that are repeated in short cycles.

As can be seen from the above explanation, there is a feedback type fuel supply system that injects fuel adjusted by a pressure regulating valve into the intake passage from an electromagnetically driven injection valve, and the fuel is seated on the valve seat in response to the fuel pressure. Alternatively, since the output shaft of the linear motor is kept in contact with a movable member that moves away from this, even slight pressure fluctuations can be adjusted by feeding back fluctuations in fuel pressure and changing the thrust of the output shaft. It is possible to open and close the pressure valve, absorbing and stabilizing pressure fluctuations caused by the opening and closing of the injection valve, and there is no need to increase the size of the valve chamber, and the opening and closing stroke of the pressure regulating valve is extremely small. Kosugi's linear motor is used, and it can be installed without increasing the overall size. It was.

Information other than fuel pressure is processed by an electronic control device to generate linear
By driving the motor to change the closing force of the pressure regulating valve and changing the fuel injection pressure value, it is possible to adapt to various operating conditions without significantly changing the 1:1 closing time ratio per unit time of the injector. It can inject and supply the corresponding fuel.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional view showing an embodiment of the present invention. 4...Engine, 8...Fuel bonder,
9...Pressure regulating valve, 10...Injection valve, 11
... Intake path, 12 ... Fuel pressure detector, 14 ... Electronic control device. 16...Solenoid, 17...Fuel passage, 18...Return passage %, 20...Valve chamber, 21...Valve seat, 22...Movable member,
23... Valve body, 27... Linear motor, 28... Output shaft. Yosanjin Nozawa Masaaki

Claims (1)

[Scope of Claims] In a feedback type fuel supply device in which fuel regulated by a pressure regulating valve is injected from an electromagnetically driven injection valve into an intake passage, the valve body of the pressure regulating valve is moved to a valve seat in response to fuel pressure. A movable member that is moved to sit or move away from the seat. A fuel pressure control device characterized in that the output shaft of a linear motor driven by a current supplied from an electronic control device is brought into contact engagement.