JPH0658225A - Fuel injection device of internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent high idle and reduce NOX after warming, when an assist air quantity is increased, in the fuel injection device of an internal combustion engine adopting an air assist construction. CONSTITUTION:This fuel injection device is constituted so that the working quantities of a fresh air control valve 6 and an exhaust control valve 9 respectively provided on a fresh air introducing passage 5 to bypass a throttle valve 1 and introduce fresh air to a fuel injection valve 3 and on an exhaust introducing passage 8 to have a suction port on an exhaust piping 23 and introduce exhaust to the fuel injection valve 3 are controlled, so as to conform the mixture ratio of fresh air and exhaust to a previously set value according to the operating condition of an internal combustion engine by a computer unit 11, and obtain an optimum combustion condition.

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 2
A throttle valve 2 mounted on 0 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 front end faces the internal combustion engine. A fuel injection valve 4 having an air assist structure that injects an optimum amount of fuel based on information from 4 is introduced into the atmosphere with 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 pressure difference between the air duct 21 of the intake pipe 15 and the intake manifold 22,
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 amount of intake air to the internal combustion engine is controlled by opening / closing the throttle valve 1. This intake air amount is detected by the air amount sensor 2. The information detected by the air amount sensor 2 is sent to a computer unit 23 which is a control means, an optimum fuel amount is set there, and an appropriate amount of fuel is injected from the fuel injection valve 3 having an air assist structure based on the signal. To be done. At this time, the assist air is sent to the fuel injection valve 3 through the atmosphere introduction passage 4 due to the pressure difference between the intake manifold pressure in the intake manifold 11 and the pressure in the air duct 21, and the fuel spray injected from the fuel injection valve 3 is injected. By colliding with, the atomization of atomized fuel is promoted.

[0004]

Since the conventional fuel injection device for a gasoline internal combustion engine is constructed as described above,
If the amount of air for promoting atomization, which is determined by the structure of the fuel injection valve 1, is increased, it may not be possible to maintain idle during warm-up, and conversely, if it is decreased, there is a problem that atomization of fuel is poor.

The present invention has been made in order to solve the above-mentioned problems, and secures an amount of assist air to atomize the fuel and prevent high idle after warming up.
An object of the present invention is to obtain a fuel injection device for an internal combustion engine that can reduce NOX in exhaust gas.

[0006]

A fuel injection device for an internal combustion engine according to the present invention includes a throttle valve mounted on an intake pipe for controlling the amount of air taken into the internal combustion engine, and the air amount mounted on the intake pipe. An air amount sensor for detecting
A fuel injection valve having a tip end facing the inside of the internal combustion engine and having an air assist structure for injecting necessary fuel; one end connected to a downstream side of the air amount sensor and the other end connected to the fuel injection valve; A fresh air introduction passage for introducing fresh air into the injection valve, a fresh air control valve for controlling the fresh air amount in the fresh air introduction passage, and a fresh air backflow which is attached to the fresh air introduction passage A check valve, an exhaust gas introduction passage having one end connected to the internal combustion engine and having an intake port for introducing exhaust gas to the fuel injection valve, and an exhaust gas that is located in the middle of the exhaust gas introduction passage and controls the amount of exhaust gas. A fuel injection by controlling a control valve, a check valve attached to the exhaust gas introduction passage to prevent backflow of exhaust gas, and controlling operation amounts of the fresh air control valve and the exhaust gas control valve according to an operating state of the internal combustion engine. With fresh air and exhaust to the valve In which a control means for controlling the coupling ratio to a preset value.

[0007]

In the fuel injection system for an internal combustion engine according to the present invention, by using a mixture of exhaust gas and fresh air as the assist air, the amount of air can be increased and the atomization of fuel can be promoted. The NOX amount can be reduced because part of the NOx is reburned.

[0008]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention.
The same or corresponding parts are designated by the same reference numerals and the description thereof will be omitted. In the figure, 5 is a fresh air introduction passage for introducing fresh air into the fuel injection valve 3 by bypassing the throttle valve 1 with a suction port downstream of the air amount sensor 2, and 6 is in the middle of the fresh air introduction passage 5. A fresh air control valve for controlling the fresh air amount, 7 is a check valve provided in the fresh air introduction passage 5 for preventing the reverse flow of fresh air, and 8 is a suction pipe in the exhaust pipe 23 and introduces exhaust gas into the fuel injection valve 3. The exhaust gas introduction passage, 9 is an exhaust gas control valve for controlling the amount of exhaust gas in the middle of the exhaust gas introduction passage 8, 10 is a check valve attached to the exhaust gas introduction passage 8 for preventing backflow of exhaust gas, 1
Reference numeral 1 controls the operating amounts of the fresh air control valve 6 and the exhaust control valve 9 in accordance with the operating state of the internal combustion engine to control the mixture ratio of fresh air and exhaust gas to the fuel injection valve 3 to a preset value. It is a computer unit that is a control means.

Next, the operation will be described. The amount of intake air to the internal combustion engine is controlled by opening / closing the throttle valve 1. This intake air amount is detected by the air amount sensor 2. An optimum amount of fuel is injected from the fuel injection valve 3 having the air assist structure based on the information detected by the air amount sensor 2. At this time, the assist air entering the fuel injection valve 3 is introduced through the fresh air introduction passage 5 arranged bypassing the throttle valve 1 and the exhaust introduction passage 8 having the suction port in the exhaust pipe 23. A fresh air control valve 6 and a check valve 7 are provided in the fresh air introduction passage 5, and an exhaust control valve 9 and a check valve 10 are provided in the exhaust introduction passage 8, which are set in advance according to the operating state of the internal combustion engine. The operation amounts of the fresh air control valve 6 and the exhaust control valve 9 are controlled by the computer unit 11 so that the mixed ratio of the fresh air and the exhaust gas thus obtained is obtained.

[0010]

As described above, according to the fuel injection device for an internal combustion engine of the present invention, since the air-fuel mixture of fresh air and exhaust gas is used as assist air, the amount of assist air for promoting atomization is increased. Even after that, it is possible to prevent high idle after warming up, and in the past, when the load was high, the assist air was difficult to flow because the intake manifold pressure approached atmospheric pressure. Since the exhaust pressure becomes high, there is an effect that a differential pressure for generating assist air can be secured.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram showing a conventional air-assist type fuel injection device.

[Explanation of symbols]

 1 throttle valve 2 air quantity sensor 3 fuel injection valve 5 fresh air introduction passage 6 fresh air control valve 7 check valve 8 exhaust introduction passage 9 exhaust control valve 10 check valve 11 computer unit (control means) 20 intake pipe 23 exhaust pipe

[Procedure amendment]

[Submission date] September 16, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

[0004]

Since the conventional fuel injection device for a gasoline internal combustion engine is constructed as described above,
If the amount of air for promoting atomization determined by the structure of the fuel injection valve 1 is increased, the idle after warming up may not be maintained, and conversely, if it is decreased, atomization of the fuel is inferior.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction content]

[0010]

As described above, according to the fuel injection device for an internal combustion engine of the present invention, since the air-fuel mixture of fresh air and exhaust gas is used as assist air, the amount of assist air for promoting atomization is increased. it is possible to prevent the high idle after warm-up also, so far in order high load of the intake manifold pressure is the assist air to approach the atmospheric pressure was difficult to flow is to utilize exhaust during high load Since the exhaust pressure becomes high, there is an effect that a differential pressure for generating assist air can be secured.

Claims (1)

[Claims] 1. A throttle valve attached to an intake pipe for controlling the amount of air sucked into an internal combustion engine; an air amount sensor attached to the intake pipe for detecting the air amount; and a tip portion inside the internal combustion engine. A fuel injection valve that faces the air injection structure and injects necessary fuel, and one end is connected to the downstream side of the air amount sensor and the other end is connected to the fuel injection valve to introduce fresh air into the fuel injection valve. A fresh air introduction passage, a fresh air control valve in the middle of this fresh air introduction passage for controlling the amount of fresh air, a check valve attached to the fresh air introduction passage to prevent a reverse flow of fresh air, and one end of the internal combustion engine An exhaust gas introduction passage having an intake port in an exhaust pipe connected to an engine for introducing exhaust gas to the fuel injection valve, an exhaust control valve for controlling an exhaust amount in the middle of the exhaust gas introduction passage, and the exhaust gas introduction passage. Mounted on the exhaust Of the check valve for preventing the backflow of the internal combustion engine, the operation amount of the fresh air control valve and the exhaust control valve is controlled according to the operating state of the internal combustion engine to control the mixture ratio of the fresh air and the exhaust gas to the fuel injection valve. A fuel injection device for an internal combustion engine, comprising: a control means for controlling a preset value.