JPS5823260A - Fuel injection device of internal combustion engine - Google Patents

Abstract

PURPOSE:To inject fuel at low pressure and incrase its economy, by injecting the fuel to an engine at one point further injecting the fuel with positive pressure of air bypassing an intake pipe. CONSTITUTION:An intake pipe 14, in the upstream of a choke valve 16, is communicated to a nozzle 21 through the first pipe 23, and the second pipe 24 is provided to press fuel 26 in a fixed oil level meter 25. Intake air 11 partially flows through the second pipe 24 to pressurize the fuel 26 in the fixed oil level meter 25, while partially flows through the first pipe 23, and is jetted from the nozzle 21 in a Venturi 17 to flow together with air in an intake pipe 14. The pressurized fuel 26 in the fixed oil level meter 25 flows through a fuel pipe 29, orifices 30-33, solenoid valves 34-37 and pipe 38, and is pulverized to a some degree by a jet stream of air then jetted from the nozzle 21. Air fuel ratio is changed by using the orifices 30-33 respectively with different area, and variable by changing ON-OFF duty of the solenoid valves 34-37.

Description

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

A conventional device of this type is shown in FIG. In the figure, 1 is an air flow rate sensor, 2 is an intake manifold, 3 is a throttle valve installed in the intake manifold 2, 4 is an injector that injects fuel, 5 is an engine, 6 is an exhaust manifold, and 7 is an air flow rate sensor 1 8 is a fuel pump;
9 is a fuel pipe connecting the discharge port of this pump 8 and the injector 4, and 10 is a regulator for keeping the differential pressure between the pressure in the intake manifold 2 and the pressure in the fuel pipe 9, that is, the fuel injection pressure constant. be.

Next, the operation will be explained. The fuel pressurized by the fuel pump 8 (generally 3.0 atmospheres or more) is raised to a fuel injection pressure of 2.5 atmospheres or more by the regulator 10 and supplied to the injector 4.The injector 4 is a type of fuel with good frequency characteristics. The solenoid valve opens in response to a valve opening signal from the control unit 7 and injects fuel. Generally, this injection is a multi-point injection in which each cylinder forming the engine 5 is injected. The valve signal is controlled by the output of an air flow sensor 1 that outputs a signal according to the amount of air taken into the engine 5, and fuel is injected to achieve a predetermined air-fuel ratio according to the amount of air taken into the engine 5. That's how it is.

However, since the fuel injection device configured as described above injects into each cylinder, it requires a large number of injectors 4 and is expensive, and variations in the performance of the injectors 4 are directly reflected in variations in the output of each cylinder. I can come out. Furthermore, there were other drawbacks such as the need for high-pressure fuel piping.

This invention was developed in order to eliminate the above-mentioned drawbacks of the conventional ones.It reduces the cost of the injection system by providing a single injection point to the engine, and also reduces the cost of injection due to variations in the performance of the injection system. The purpose of this invention is to eliminate variations in the output of cylinders and inject fuel using the positive pressure of air that has been pumped, thereby providing an inexpensive fuel injection device with low injection pressure.

An embodiment of the invention will be described below with reference to the figures.

In FIG. 2, 11 is the air that the engine 12 takes in, and 13 is the air that the engine 12 takes in.
14 is an air cleaner, 14 is an intake pipe that guides the intake air 11 through an intake manifold 151, 16 is a choke valve provided in the intake pipe 14, 17 is a venturi provided in the intake pipe 14, and 18 is the venturi in the intake pipe 14. 19 is an exhaust manifold, 20 is exhaust gas, 21 is a nozzle provided on the venturi 17 for generating an air jet, and 22 is fuel injected from this nozzle 21. 23 is a first pipe that communicates the intake pipe 14 upstream of the choke valve 16 and the nozzle 21; 24 is a second pipe that pushes out the fuel 26 in the constant oil level needle 25; and 27 is a pipe that connects the constant oil level needle 25. Float, 28 is a needle valve, 29 is an orifice 30, 31, 32, 3 in which the fuel 26 in the constant oil level needle 25 is arranged in parallel.
Fuel pipes 34, 35, 36, and 37 lead to the nozzle 21, solenoid valves 34, 35, 36, and 37 are provided in series with the orifices 30 to 33, and 38 is a pipe to lead the fuel metered by the orifices 30 to 33 to the nozzle 21.

Next, the operation will be explained. First, during normal driving, that is, when the engine 12 is running with the choke valve 16 fully open and the throttle valve 18 at an appropriate opening angle, the intake air 11 flows through the intake pipe 14, passes through the throttle valve 18, and then passes through the intake manifold. 15
is supplied to the engine 12. A part of the intake air 11 is
At the same time, a part of the intake air 11 passes through the first pipe 23 and becomes an air jet through the nozzle 21 of the venturi 17, and flows into the intake pipe 14. Combine with the air inside. The fuel 26 in the pressurized constant oil level needle 25 flows through the fuel pipe 29 and the orifice 3.
0 to 33, the solenoid valves 34 to 37 and the piping 38 are atomized to some extent by the air jet, and then ejected from the nozzle 21. Therefore, the intake air 11 is venturi 17
As it passes through, it mixes with fuel, becomes an air-fuel mixture, and is supplied to the engine 12. If the pressure loss for the air flowing through the first piping 23 is made to occur at the nozzle 21, the air flow rate will be determined when the pressure loss and the negative pressure generated at the venturi 17 become equal, so that the air flowing through the first piping 23 will flow. The ratio of the air flow rate to the total intake air flow rate flowing through the intake pipe 14 is constant. Similarly, from the constant oil level needle 25 to the fuel pipe 29
The ratio of the fuel flow rate flowing through the pipe 38 to the air flow rate flowing through the first pipe 23 is made constant by causing a pressure drop for the fuel to occur in the oriices 30 to 33. Therefore, it can be seen that with the above configuration, the ratio of the fuel flow rate to the total intake air flow rate, that is, the air-fuel ratio, becomes constant.

In general, the engine 12 is not always operated at a constant air-fuel ratio;
．． 1 to 1.2), and 14.6 (1 to 1.2) in the 10 mode regulation area.
, 0 theoretical mixing ratio) and 1 in the region where only output is required.
2 The air-fuel ratio changes as (0,9). In Fig. 2, the air-fuel ratio is changed by using oriices 30 to 33 with different areas, and the solenoid valves 34 to 37 are turned on and off.
This is possible by changing the duty of the FF. For example, the area of orifice 33 is the fuel flow rate of engine 1.
It is assumed that the air-fuel ratio is set to be the air-fuel ratio for economical driving of 2. There are four possible values for the duty of each of the solenoid valves 34, 35, and 36 (for example, if the repetition period is 100m5ee,
), the orifice 32 is the orifice 3
Keep the area the same as 3, and below 1/4 of orifice 31
When set to , the fuel flow rate flowing through the orifice 33 can be corrected from about 1.7 inches to 130 inches in units of 1.7 inches by combining the duties of the solenoid valves 34 to 36. A more concrete explanation of this is as follows. Now, if the engine 12 enters the 10 mode regulation area from economical driving with an air road riding factor of 1.2, it is necessary to increase the amount of fuel by 20 inches. In this case, 20 coefficients/1, 7% =
11.76, so converting this to the westward system, the closest value is 30. Therefore, if the solenoid valve 35 is opened at duty 3/4, a correction of 3 x 4 x 1.7 = 20.4 chi is possible. . In addition, for other acceleration corrections, atmospheric temperature corrections, cooling water temperature corrections, etc., signals from the respective sensors (not shown) are processed by the CPV (not shown), and the solenoid valves 34 to 34
This can be done easily by controlling 36. Furthermore, by appropriately closing the choke valve 16 during startup, the first pipe 23
It is possible to increase the flow rate of air flowing through the fuel tank and create a rich mixture.

In the embodiment of the present invention, the throttle valve 18 is provided downstream of the venturi 17, but it may also be provided upstream of the first and second pipes 23, 24, or a solenoid valve or orifice may be provided. It is also possible to incorporate it into the oil level needle 25.

As described above, according to the present invention, the injection device has a constant oil level needle,
Since the fuel injection device is composed of a solenoid valve and an orifice, the cost of the device is significantly reduced, and the fuel injection device has low injection pressure, making it an economically preferable fuel injection device. It also has the advantage that corrections for various driving conditions can be digitized.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a conventional fuel injection device, and FIG. 2 is a configuration diagram of a fuel injection device according to the present invention. 12... Engine, 14... Intake pipe, 15... Intake manifold/l/)', 16... Choke valve, 17...
Venturi, 18... Throttle valve, 21... Nozzle,
23...first piping, 24...second piping, 25.
... Constant oil level needle, 30-33 ... Orifice, 34-3
7... Solenoid valve. Agent Shin Kuzuno −

Claims (1)

[Scope of Claims] (1) A fuel injection device for an internal combustion engine having a constant oil level needle, a throttle valve, a choke valve, a venturi, and a nozzle,
A first pipe that communicates between the upstream of the choke valve and the nozzle, and a second pipe that also communicates between the upstream of the choke valve and the constant oil level needle are provided, and the constant oil level needle and the nozzle are connected. 1. A fuel injection device for an internal combustion engine, characterized in that a fuel pipe is provided, two or more electromagnetic valves are arranged in parallel in this pipe, and an oriswiss is provided in series with each electromagnetic valve. Injection device. (3) Control the opening time of the solenoid valve by turning it ON and OFF.
- The value of this duty (
4) At least two of the plurality of orifices are on the same surface M
The fuel flow rate injection device has R and is determined by this area. (5) The area of the other oriice is calculated as the duty of the solenoid valve (
6) At least a solenoid valve corresponding to an orifice with an area corresponding to the fuel flow rate when the engine is running at full speed. Correct the fuel flow rate by changing the duty of the solenoid valve accordingly.