JP2738791B2 - Fuel injection device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device for an internal combustion engine having an air assist structure.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional fuel injection device for a gasoline internal combustion engine having an air assist structure. 1 is intake pipe 1
A throttle valve attached to 5 for controlling the amount of air to the internal combustion engine, 2 is an air amount sensor upstream of the throttle valve 1 for detecting the amount of air, and 3 is an air amount sensor 2 whose tip faces the internal combustion engine. A fuel injection valve 4 having an air-assisted structure for injecting an optimum fuel amount based on the information from the fuel injection valve 4 has one end connected to the downstream side of the air amount sensor 2 and the other end connected to the fuel injection valve 3. In the passage, due to the differential pressure between the air duct 16 of the intake pipe 15 and the intake manifold 11,
The assist air from the atmosphere introduction passage 4 collides with the spray injected from the fuel injection valve 3.

Next, the operation will be described. The opening and closing of the throttle valve 1 controls the amount of air taken into the internal combustion engine. This intake air amount is detected by the air amount sensor 2. Information detected by the air amount sensor 2 is sent to a computer unit 8 as a control means, where an optimum fuel amount is set, and based on the signal, an appropriate amount of fuel is injected from a fuel injection valve 3 having an air assist structure. Is done. At this time, the assist air is generated by the pressure difference between the intake manifold pressure in the intake manifold 11 and the pressure in the air duct 16.
By being sent to the fuel injection valve 3 through the air introduction passage 4 and colliding with the fuel spray injected from the fuel injection valve 3, atomization of the spray fuel is promoted.

[0004]

The conventional fuel injection system for an internal combustion engine is constructed as described above.
Is open, that is, when the intake manifold pressure is close to the atmosphere, the differential pressure between the air upstream and downstream of the fuel injection valve 3 having the air assist structure becomes small, the amount of assist air decreases, and atomization of spray cannot be expected by air assist. There was such a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a fuel injection device for an internal combustion engine which can always secure a predetermined amount of assist air in all operating states of the internal combustion engine. The purpose is to gain.

[0006]

A fuel injection device according to the present invention is provided with a throttle valve attached to an intake pipe for controlling an amount of air taken into an internal combustion engine, and is attached to the intake pipe to detect the amount of air. An air amount sensor, a fuel injection valve having a tip portion facing the internal combustion engine and having an air assist structure to inject required fuel, and one end connected to the downstream side of the air amount sensor and the other end being the fuel injection valve An air introduction passage connected to the air introduction passage, an air pump attached to the air introduction passage and supplying pressurized air to the fuel injection valve, and a bypass passage having respective ends connected to the upstream and downstream sides of the air pump, A pressure regulator attached to the bypass passage for adjusting a pressure difference between an air upstream side and an air downstream side of the fuel injection valve, one end communicating with the air upstream side of the fuel injection valve and the other end connected A pressure sensor that communicates with the air downstream side of the fuel injection valve and detects the pressure difference; and, based on information from the pressure sensor, the pressure between the air upstream side pressure and the air downstream side pressure of the fuel injection valve. Control means for outputting a signal for controlling the differential pressure to be always constant to the pressure regulator, and a check valve attached to the air introduction passage upstream of the air pump to prevent backflow of the pressurized air. It is a thing.

[0007]

According to the present invention, an air pump for generating pressurized air is disposed in the atmosphere introducing passage, and the control means is configured to perform control based on pressure information from a pressure sensor for detecting a differential pressure between upstream and downstream of the fuel injection valve. differential pressure air upstream and downstream of the fuel injection valve is adapted to control the pressure regulator so that the predetermined pressure is in any operating condition of the internal combustion engine.

[0008]

[Embodiment 1] An embodiment of the present invention will be described below with reference to the drawings. FIG.
Is a block diagram showing one embodiment of the present invention, and the same or corresponding parts as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted. In the figure, reference numeral 5 denotes an air pump for supplying pressurized air for air assist to the fuel injection valve 3, and reference numeral 6 denotes a fuel injection valve attached to a bypass passage 10 connecting the upstream and downstream of the air pump 5. A pressure regulator 3 for adjusting the air upstream pressure 3 has one end connected to the air introduction passage 4 and the other end connected to the intake manifold 11, and detects a differential pressure between the air upstream side and the downstream side of the fuel injection valve 3. The pressure sensor 8 outputs a signal to the pressure regulator 6 based on information from the pressure sensor 7 so as to control the differential pressure between the air upstream side and the downstream side of the fuel injection valve 3 to be always constant. A computer unit 9 serving as a control means is a check valve attached to the air introduction passage 4 on the upstream side of the air pump 5 for preventing the compressed air from flowing backward.

Next, the operation will be described. The opening and closing of the throttle valve 1 controls the amount of air taken into the internal combustion engine. This intake air amount is detected by the air amount sensor 2. An optimum fuel amount is injected from a fuel injection valve 3 having an air assist structure based on information detected by the air amount sensor 2. At this time, the assist air entering the fuel injection valve 3 is generated by a differential pressure between the air upstream pressure of the fuel injection valve 3 generated by the air pump 5 and the intake manifold pressure in the intake manifold 11. A pressure regulator 6 is provided in a bypass passage 10 that connects the upstream and downstream of the air pump 5. Based on the output of the pressure sensor 7, the differential pressure between the upstream and downstream of the air of the fuel injection valve 3 is constantly maintained in all operating states of the internal combustion engine. The computer unit 8 controls the pressure regulator 6 so as to obtain a predetermined pressure. The check valve 9 prevents the pressurized air generated by the air pump 5 from flowing backward.

[0010]

As described above, according to the present invention, the differential pressure between the upstream and downstream of the air of the fuel injection valve having the air assist structure is configured to be always a predetermined pressure in all operating states of the internal combustion engine. In addition, the amount of assist air can be ensured even under a heavy load, and atomization of the spray injected from the fuel valve can be achieved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a fuel injection device for a gasoline internal combustion engine according to one embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating an example of a conventional fuel injection device for an air-assisted gasoline internal combustion engine.

[Explanation of symbols]

 Reference Signs List 1 throttle valve 2 air amount sensor 3 fuel injection valve 4 atmosphere introduction passage 5 air pump 6 pressure regulator 7 pressure sensor 8 computer unit (control means) 9 check valve 10 bypass passage 15 intake pipe

Claims (1)

(57) [Claims] A throttle valve attached to an intake pipe for controlling an amount of air taken into the internal combustion engine; an air quantity sensor attached to the intake pipe for detecting the air quantity; and faces, a fuel injection valve for injecting necessary fuel takes air assistance structure, and the atmosphere introduction passage having one end and the other end connected to the downstream side of the air flow sensor is connected to the fuel injection event, this An air pump attached to the air introduction passage for supplying pressurized air to the fuel injection valve, a bypass passage connected to an upstream end and a downstream end of the air pump, and the fuel injection valve attached to the bypass passage A pressure regulator for adjusting the pressure difference between the air upstream side and the air downstream side, and one end communicating with the air upstream side of the fuel injection valve and the other end communicating with the air downstream side of the fuel injection valve; Detect And a signal for controlling the differential pressure between the pressure on the air upstream side and the pressure on the air downstream side of the fuel injection valve based on the information from the pressure sensor and the pressure sensor. A fuel injection device for an internal combustion engine, comprising: control means for outputting to a regulator; and a check valve attached to the air introduction passage upstream of the air pump to prevent backflow of the pressurized air.