JPS6324138B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply device for a ignited internal combustion engine.

Normally, a carburetor or an electronically controlled fuel injection system (EFI) is used to control the air-fuel ratio supplied to the engine, but in both cases the amount of air is independently or preferentially selected as an initial value. The system is such that the corresponding fuel is calculated accordingly. With this air-first fuel supply control (EFC) system, it is difficult to achieve both fuel economy and emission concentration. For example, if the amount of air initially selected is changed by the operator almost in a step-like manner, the step response will be delayed because the density of fuel is greater than that of air, and during acceleration, the front and rear pressures of the throttle valve will change over the time of the step change. At the beginning of the valve step change, a large amount of air flows in.
In such a case, correction must be made to maintain the air-fuel mixture in the combustion chamber within the flammable range. Therefore, the present inventors first developed a fuel command potentiometer that detects the amount of accelerator pedal depression;
outputs from control elements such as air flow sensing devices in the intake bore and potentiometers coupled to throttle valve actuators;
Electrical signals from correction elements such as engine coolant temperature, atmospheric temperature, fuel supply line pressure, etc. are input to the control unit, and are compared with pre-programmed memories based on the functional relationships between the parameters of the control elements and correction elements. ,
We have invented a fuel supply system using fuel priority air supply control (EAC), which operates a throttle valve based on the required air volume calculated from the fuel flow input to determine the optimum air volume. In such a system, there is little delay in both the rise and fall of fuel, and the mixture ratio supplied to the combustion chamber can be easily selected and programmed, especially for vehicles that frequently accelerate and decelerate. Total fuel efficiency in city driving is significantly improved, and emissions control becomes easier.

However, in the system of the above invention, if the throttle valve actuator or control unit becomes defective for some reason and no longer operates normally, the engine will stop and the vehicle will be unable to run on its own. Become.

In view of the above points, the present invention provides a fuel supply system using fuel priority type air supply amount control, in which a throttle valve driven by a control value of a control unit is installed in a first bore of a twin body. Inside the second bore, a second throttle valve that is directly rotated by the movement of the bench lily and the accelerator pedal, and a fuel passage leading from the float chamber to the bench lily are arranged to provide an emergency carburetor. When an abnormality such as a failure of the control unit occurs, the first throttle valve is closed.
The second bore carburetor is switched to supply a mixture with a constant air-fuel ratio A/F, for example, in proportion to the amount of depression of the accelerator pedal. In other words, under normal conditions, the control unit operates to perform A/F variable EAC control over the entire operating range, and in the event of a failure of the control unit or actuator, the carburetor performs air priority control, allowing the engine to be returned to the service station without stopping. Alternatively, it is possible to drive the vehicle with low output to a drive-in area or the like.

Embodiments of the invention will now be described with reference to the drawings.

Figure 1 shows a twin body in the middle of intake bore 1,
A first throttle valve 2 and a second throttle valve 3 are respectively installed, and a solenoid valve type injector 4 is arranged downstream of the throttle valves. The injector 4 is not limited to a single point injection type as shown in the figure, but may also include several injectors, or a multi-point injection type with one injector installed in each intake manifold for each cylinder. Good too. The injector is an electromagnetic valve type injector that changes the valve opening time width or the valve opening frequency to increase or decrease the fuel injection amount using a solenoid drive current. Further, the main injector is supplied with fuel from the regulator, the fuel supply pressure is detected by the sensor 14 in the return passage, and the surplus is returned to the fuel tank (not shown) via the relief valve 31.

The movement of the accelerator pedal 5 moved by the operator is detected by a fuel command potentiometer 7 via a linkage 6, and an output voltage depending on the amount of depression is outputted to a control unit 10.

An intake air temperature sensor 11 is provided in the bore downstream of the air cleaner 8, and pressure sensors 12 and 13 forming an air flow sensing device are provided upstream and downstream of the throttle valve 2. In addition to the intake air temperature sensor 11, a fuel supply pressure sensor 14, an engine coolant temperature sensor 15, an engine rotation speed sensor 16, and the like are arranged as correction elements. The control unit 10 receives outputs from the fuel command potentiometer 7, air flow sensors 12, 13, potentiometers or encoders connected to the throttle valve actuator 9, and electrical signals from various correction elements. Based on the required air volume calculated from the fuel flow input, the DC motor is
The actuator 9, such as a stepping motor, is driven to operate the throttle valve 2 to determine the optimum amount of air. As shown in the figure, a bench lily part 17 is formed in the bore in which the second throttle valve 3 is installed, a float chamber 18 is arranged outside, and a fuel passage 20 having a hole 19 is provided from the float chamber to the bench lily part. The vaporizer is constructed using The second throttle valve 3 may be operated directly by the movement of the accelerator pedal 5 via the rod 21, or may be operated by intervening a clutch 22 that is turned on when the control unit 10 or the like fails. .

In the above device, when the control unit 10 is operating normally, the A/F variable air-fuel mixture is supplied appropriately depending on the operating conditions of the engine as the vehicle travels, but due to some reason, the actuator 9 If the control unit 10 becomes defective or the control unit 10 itself malfunctions, an alarm will be issued, the switch will be operated to turn off the power to the control unit 10, and the first control unit 10 will be turned off.
Close throttle valve 2. When this condition occurs, the fuel tank 19 is opened, fuel is discharged from the bench lily, and the second throttle valve 3 is operated according to the amount of depression of the accelerator pedal to turn on the A/F.
A constant mixture is supplied to the engine, the engine is operated at low output, and the vehicle is driven until it reaches a service station or the like.

FIG. 2 shows another embodiment in which a small carburetor 25 is attached to the side of the intake bore 1 where the throttle valve 2 is attached. The carburetor cylinder 2 is installed on the bore wall before and after the throttle valve 2.
The inlet 23 and outlet 24 of No. 6 are opened, and a bolt 28 is passed through a flange 27 formed in the vicinity thereof, and the carburetor main body is tightened and fixed to the bore. The air body 26 is bent into a substantially U-shape, and has a bench lily portion 17 inside.
is formed, and a sub-throttle valve 3 is installed downstream thereof. Float chamber 18 at the top of the air body
A fuel passage 20 is formed from the float chamber to the bench lily part, and a needle valve 30 that is opened and closed by a solenoid 29 is provided at the upper end of the fuel passage 20.
is located. The carburetor 25 can be installed by simply passing the bolt 28 through the flange 27 and tightening it.
It is easy to assemble, and it is also convenient to remove and replace when it becomes defective.

In the case of the embodiment shown in FIG. 2 as well, when the control unit is operating normally, the air supply amount is controlled by the output of the actuator 9 to supply the optimum air-fuel mixture for the operating conditions of the engine. If a trouble occurs in the actuator 9 or the control unit, the main throttle valve 2 is closed and the solenoid 29 is energized to open the fuel passage 2.
0 to discharge fuel. When you press the accelerator pedal 5 in this state, the movement of the accelerator pedal is directly transmitted to the sub throttle valve 3, and the A/
It is possible to supply a constant air-fuel mixture to the engine and perform low output operation.

As described above, according to the present invention, in the injection system using fuel priority type air supply amount control, apart from the air supply amount control system operated by the control value from the control unit,
Since it is equipped with a carburetor for the emergency engine, there is no need to switch to the carburetor system and suddenly stop the engine in the event of a failure of the control unit or throttle valve actuator.
The safe operation of the vehicle can be ensured by making it possible to operate the A/F at a constant low output.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of the apparatus of the present invention, and FIG. 2 is a system diagram of another embodiment. 1: Intake bore, 2, 3: Throttle valve, 4: Solenoid valve type injector, 5: Accelerator pedal, 7: Fuel command potentiometer, 9:
Actuator, 10: control unit,
11: Intake air temperature sensor, 12, 13: Air flow sensor, 14: Fuel supply sensor, 15: Engine cooling water temperature sensor, 16: Engine speed sensor, 17: Bench lily section, 18: Float chamber,
20: fuel passage, 25: carburetor.

Claims (1)

[Claims] 1. A fuel command potentiometer that includes a fuel injector and a control unit with an electronic calculation function and detects the amount of accelerator pedal depression;
Outputs from control elements such as an air flow sensing device in the intake bore, a potentiometer or an encoder coupled to a throttle valve actuator, and electrical signals from various correction elements are input to the control unit, and the control elements The function relationship between the parameters of the correction element and the parameters of the correction element is compared with a pre-programmed memory, and the throttle valve is operated based on the required air amount calculated from the fuel flow input to determine the optimal value of the air amount. In this device, the intake bore is double-bore, one bore is equipped with a first throttle valve that is rotated by the operation of a throttle valve actuator based on the control value of the control unit, and the other The bore includes a bench lily portion, a fuel passage that discharges fuel from the float chamber to the bench lily portion, and a second valve that is rotated directly by pressing the accelerator pedal.
1. A fuel supply system for an internal combustion engine, characterized in that a throttle valve is arranged to supply a mixture with a constant air-fuel ratio in the event of a failure of a control unit or an injector. 2. The fuel supply device according to claim 1, wherein the fuel passage has a valve that is closed when the control unit or the throttle valve actuator is operating normally and is opened when an abnormality occurs. . 3 The correction elements are based on engine cold water temperature or engine cylinder head temperature, engine speed,
The fuel supply system for an internal combustion engine according to claim 1, which is a group of sensors for measuring atmospheric temperature, atmospheric pressure, fuel supply line pressure, etc. 4. The air flow sensing device detects the pressure difference before and after the throttle valve, the electrical output proportional to the amount of intake air, or the output of a variable frequency such as Karman vortex or ultrasonic wave, etc. Claim 1 Fuel supply device for the internal combustion engine described. 5 The fuel injectors controlled by the main control unit may be one or more with single-point injection downstream of the throttle valve, or one per cylinder with multi-point injection in the intake manifold. A fuel supply device for an internal combustion engine according to claim 1, wherein the fuel supply device is installed in an internal combustion engine.