JPS59188064A - Fuel supply device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To easily secure an optimum amount of fuel to be injected as required by an injector, and efficiently utilize a fuel pump, by controlling a fuel pressure regulating means and the fuel pump of variable discharge type in response to a detection value of an intake air vacuum detction means. CONSTITUTION:There is provided a fuel pressure regulating means 9 in a fuel supply system including an injector 7 to which fuel pressurized by a fuel pump 1 is supplied. A discharge amount of the fuel pump 1 is rendered variable by a control means 2 for controlling voltage to be applied to the fuel pump 1. The fuel pressure regulating means 9 decides whether an output from an intake air vacuum sensor 14 is positive or negative by way of a first control means 100, and according to the decision, it acts to control a pressure regulator selecting solenoid 93, wherein a fuel pressure is regulated by opening and closing a cut- off valve 931. The voltage control means 2 decides whether the output from the vacuum sensor 14 is positive or negative by way of a second control means, and according to the decision, it acts to increase and decrease a discharge amount of the fuel pump 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply system for an internal combustion engine that changes the discharge amount from a fuel pump and adjusts the fuel pressure in accordance with the injection amount of an injector.

Conventionally, a fuel supply system for an internal combustion engine includes a pressure regulator in a fuel supply system including an injector, and the pressure regulator maintains a constant fuel pressure and supplies the fuel to the injector.

If the fuel pump used in such a fuel supply system for an internal combustion engine is used as is in a fuel supply system for an internal combustion engine with a turbocharger, the fuel pump that is used for the fuel supply system for an internal combustion engine with a turbocharger will also be used outside the plate during turbocharging as well as for the normal injection of the injector. Since the discharge air and discharge pressure of the fuel pump far exceed the injection amount and fuel pressure, the amount returned to the fuel tank becomes excessive, causing the disadvantage that the fuel temperature in the tank increases and the inclusion of air bubbles increases. However, there is a problem in that the discharge pulsation generates considerable noise even when idling.

The present invention was developed with a focus on these problems, and detects the intake absolute pressure in the intake pipe, which determines the engine condition, and simultaneously adjusts the fuel pressure and the fuel pump discharge amount according to the detected value. The purpose of this change is to ensure the injection amount necessary for the injector, prevent the circulation of fuel that exceeds the injection amount of the injector, and make efficient use of the fuel pump and reduce noise.

FIG. 1 is an overall configuration diagram clearly showing the configuration of the present invention.

In a fuel supply system for an internal combustion engine, which includes a fuel pressure adjustment means 9 and a variable discharge amount fuel pump 1 in a fuel supply system including an injector 7, an intake pressure detection means 14 detects the absolute pressure inside the intake pipe 4. a first control means for controlling the fuel pressure adjusting means 9 according to the detected value; and a second control means for controlling the variable discharge amount fuel pump 1 according to the detected value.
and a control means.

FIG. 2 shows an embodiment in which the present invention is applied to a spark ignition engine.

In FIG. 2, 1 is a fuel pump with variable discharge amount;
The fuel tank is connected to a battery 3 via a fuel tank applied voltage control means 2, and a driving voltage is applied thereto.

Then, the intake absolute pressure in the intake pipe 4 (hereinafter referred to as MAP)
The fuel according to the amount is sucked up from the fuel tank 5 and sent to the injector 7 through the oil feeding vibro.

The fuel pump applied voltage control means 2 receives the fuel pump applied voltage control signal O83 from the arithmetic unit 8 according to the engine state, and controls the fuel pump applied voltage by switching the resistance value connected between the battery 6 and the fuel pump 1. For example, it is composed of a relay that switches between the a-switch 201 and the 71 switch 202. The output voltage at that time is output as a battery voltage signal S5.

Note that in order to continuously change the fuel pump applied voltage, duty control that changes the duty of the I pulse can also be used as the fuel bong applied voltage control number 083.

Reference numeral 9 denotes a fuel pressure adjusting means, and FIG. 3 shows an embodiment of the fuel pressure adjusting means. In Figure 3, 91
92 is a pressure regulator for high pressure, 93 is a pressure regulator switching solenoid, etc.

The pressure regulating oil passage 10 communicating with the injector 7 is
Shunted within the fuel pressure adjustment means 9, one portion M 1011d
The fuel enters the high pressure flexure regulator 91 and reaches the fuel return I tube 11 via a diaphragm 912 pressed by a spring 911, and the other branch 102 is connected to the cutoff valve 93 of the pressure regulator switching solenoid 96.
1 to the low pressure pressure regulator 921 (entered,
Pressed by the spring 921/C diaphragm 9
22 leads to 1 fuel return pipe 11V. In addition,
Each pressure regulator 91, 9'2 has a pressing force that balances the fuel pressure with each diaphragm 912, 922.
A pressure balance pipe 91 leading into the intake pipe 4
3,923 are provided respectively. Then, the pressure regulator (21I conversion solenoid 95VC) receives the fuel pressure control signal O81 from the calculation device 8, opens and closes the cutoff valve 961 in the pressure regulating oil branch 102 that enters the low-pressure Luxure gierator 92, and controls the injector according to the engine condition. In order to secure an injection amount of 7, the fuel pressure is adjusted in 11 steps.Furthermore, the fuel pressure can be adjusted in multiple stages or continuously.

The injector 7 receives the discharge amount according to the MAP from the fuel pump 1, and the fuel whose pressure is adjusted according to the MAP by the fuel pressure adjustment means 9 is supplied to the engine state 6r (accordingly, a basic injection pulse width to be described later is calculated). Based on the injector drive signal 08m of the performance device 8, the throttle body 12
Inject inside.

The throttle body 12 has an injector 7 and a throttle valve 13 disposed therein, and takes in necessary intake air into the intake air-4 by opening and closing the throttle valve 16 depending on the engine state.

A MAP sensor 14 serving as intake pressure detection means and an intake temperature sensor 15 are attached to the wall of the intake pipe 4. Then, the MAP sensor 14 detects the MAP and outputs the MAP signal S2, and the intake temperature sensor 15
The intake air temperature is detected and an intake air temperature signal ■S1 is output.

16 is a cylinder in which a piston 17 slides to form a combustion chamber 18, and a water temperature sensor 19 is attached to the tube wall. The water temperature sensor 19 detects the temperature of the cooling water in the cylinder 16 and outputs a water temperature signal S4.

20 is a turbocharger that guides engine exhaust gas to an exhaust turbine (not shown), uses the generated power to turn a turbo compressor (not shown), and supplies pressurized air to the intake pipe 4. .

21 is a crank angle signal switch S3 according to the crank angle change.
This is a crank angle sensor that outputs .

The arithmetic device 8 is, for example, a central processing bag [('CPV)81,
It is composed of a microcomputer, etc., including a read-only memo IJ (R, OM) 82, a read/write memory (IM) 83, and a human output interface 84. The arithmetic unit 7 uses various signals IS1 to S6 given from the various sensors described below as human power, and various control signals for optimally controlling the engine, such as fuel pressure control signal QS, injector drive signal O.
82, and a fuel pump applied voltage control signal O83.

FIG. 4 is a flowchart for executing the control calculation of this embodiment, and Pl-Pl6 in the figure indicate each step of the flowchart.

Next, the operation of this embodiment will be explained based on FIG.

In FIG. 4, first, M of the intake pressure sensor 14 is set to Pl.
The MAP is read based on the AP signal I8g. next,
Crank angle signal IS3 of crank angle sensor 21 at P2
Read the rotation speed based on

Furthermore, the intake temperature signal I81 of the intake temperature sensor 15 is input to the PS.
Based on this, read the intake air temperature.

At P4, the suction efficiency corresponding to the current MAP and rotation speed is looked up from the suction efficiency data table determined by the MAP and rotation speed.

In PS, mainly water temperature sensor 1? The target air/fuel mixture ratio is calculated based on the water temperature signal ISA.

At P6, it is determined whether MAP is 0 or more, and if YES, the process goes to P.

In P7, the flow coefficient of the injector 6 when id, M, and AP are 0 or more is calculated.

In the PS, a fuel pressure control signal O8l is sent to the fuel pressure adjustment means 9, the pressure regulator control solenoid 93 is operated, and the pressure regulator oil shunt 1012 that enters the low pressure pressure regulator regulator 92 is closed by its shutoff valve 931. Therefore, the high-pressure pressure regulator 91 is activated and fuel regulated to a high pressure is added to the injector 7.

At P9, the fuel pump applied voltage control signal O83 is sent to the fuel pump applied voltage control means 2, and the low switch 202 is turned off. Therefore, high pressure is applied to the fuel pump 1 and the discharge amount increases.

PIO calculates the basic injection pulse width. The basic injection pulse width is: Basic injection pulse width = (Basic injection pulse constant x Absolute pressure in the intake pipe x Intake efficiency) / (Intake air temperature x Target mixture ratio of air and fuel) It is calculated based on the formula: = (constant x cylinder volume)/injector flow coefficient.

At pH, the basic pulse width signal is output by the output counter circuit (
(not shown), and is further sent to the injector 7 as an injector drive signal O82, and the amount of fuel corresponding to the engine condition B of turbocharging injection is injected.

Moreover, if MAP is less than 0 and the determination is NO in the above P6, the process goes to P12.

At pH 1, the flow coefficient island of the injector 7 with MAP of 0 and no droplets is calculated.

At Pl3, the fuel pressure control signal 081 is sent to the fuel pressure adjusting means 9.
The pressure regulator control solenoid 9'5 is opened to open the shutoff valve 931 and operate the low pressure pressure regulator 92.

At Pl4, it is determined whether the voltage of the battery 3 is 10V or more, and if YES, the process goes to Pts.

At Pl5, the fuel pump applied voltage control signal O83 is sent to the fuel pump applied voltage control means 2, and the low switch 202 is
Turn on and apply low voltage to the fuel pump.

Next, go to Plo, calculate the injection pulse width as described above, and send the injector drive signal O8 through 'Pit.
3 is sent to the injector 7, and the amount of fuel corresponding to the engine state of normal injection is injected from the injector 7.

Further, when it is determined in P14 that the battery voltage is less than 10V, the process goes to P9. At P9, the fuel pump applied voltage control signal O8l is sent to the fuel pump applied voltage control means 2.
, the low switch 202 is turned off, and only the high switch 201 is connected to the fuel pump 1.

This is a special treatment for when the battery pressure drops! It is. Next, it goes to PIO, calculates the fuel injection pulse width as described in 7 above, passes through Fil, and sends the injector drive signal 08. is sent to the injector 7, and the amount of fuel is injected from the injector 7 according to the engine state between normal injection and turbocharged injection.

As explained above, in the fuel supply system for an internal combustion engine according to the present invention, the fuel pressure adjustment means is controlled in accordance with the detected value of the absolute pressure in the intake pipe in a region where the injection amount is small such as during idling or normal injection. By lowering the fuel pressure and controlling the variable discharge volume fuel pump to reduce the discharge volume,
While ensuring the necessary injection amount for the injector, efficient use of the fuel pump can be achieved, and noise can also be reduced.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of the present invention, FIG. 2 is a diagram of an embodiment of the present invention, and FIG. 6 is a diagram of a specific embodiment of the fuel pressure adjusting means.
and FIG. 4 is an embodiment diagram of a flowchart for controlling and calculating the embodiment. DESCRIPTION OF SYMBOLS 1...Fuel pump, 2...Fuel pump applied voltage control means, 6...Battery, 4...Intake pipe, 5...
Fuel tank, 6...oil pipe, 7...injector, 8...computing device, ? ...Fuel pressure adjustment means, 1
0...Regulation pond M, 11...Fuel return pipe, 1
2... Throttle body, 13... Throttle valve,
14...MAP sensor, 15...Intake temperature sensor, 16...Cylinder, 17...Piston, 18...
...Combustion chamber, 19...Water temperature sensor, 20...Turbo charger, 21...Crank angle sensor, ISl
...Intake temperature signal, ■S2...MAi) signal, ■S3
...Crank angle signal, ■S4...Water temperature signal, ■S5
... Battery voltage signal, O8, ... Fuel pressure control signal, O82 ... Injector drive signal, O83 ...
・Fuel pump applied voltage control signal. Applicant: Isunu Jidosha Co., Ltd. Representative: Patent attorney: Sangai Tsuji (1 person)

Claims (1)

[Claims] In a fuel supply system for an internal combustion engine, which includes a fuel pressure adjustment means and a fuel pump with variable discharge amount in a fuel supply system including an injector, the intake pressure detection means detects the absolute pressure in the intake pipe, and the detected value is A fuel supply device for an internal combustion engine, comprising: a first control means for controlling the fuel pressure adjusting means according to the fuel pressure adjustment means; and a second control means for controlling the variable discharge amount fuel pump according to the detected value thereof.