JP2757652B2 - Fuel supply 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 supply device for an internal combustion engine, and more particularly to a fuel supply device for introducing air (assist air) for promoting atomization of fuel downstream of a fuel injection valve. About improvement.

[0002]

2. Description of the Related Art Conventionally, a part of intake air is pumped from an intake passage on the upstream side of a throttle valve to a downstream side of an injection hole of a fuel injection valve as an assist air by an air pump to assist fuel injected from the fuel injection valve. Fuel is atomized by impinging air, which improves combustion and
2. Description of the Related Art An air-assisted fuel injection valve designed to improve fuel efficiency and exhaust properties is known (see Japanese Patent Application Laid-Open No. 63-106357).

[0003] Referring to Fig. 6, a fuel injection valve (not shown) is built in the main body of the air-assisted fuel injection valve 1, and the air-assisted fuel injection valve 1 is provided with the fuel injection valve. An air gallery 4 for introducing pressurized air discharged from the air pump 2 through the air introduction pipe 3 is mounted downstream of the injection hole. The air assist fuel injection valve 1 injects fuel mixed with fuel from the fuel injection valve and assist air.

The fuel in which the fuel and the assist air are mixed is injected into a position near the communication port between the intake port 6 and the combustion chamber 7 through an extension pipe 5 connected to the tip of the air-assisted fuel injection valve 1. You. The air introducing pipe 3 is provided with a pressure accumulator 8 in which pressurized air from the air pump 2 is stored. In addition, a bypass pipe 9 communicating the air pump 2 upstream of the air pump 2 with the air pump 2 and the pressure accumulating vessel 8.
The bypass pipe 9 is provided with an air regulator 10 for relieving excess air and maintaining a constant pressure in the air introduction pipe 3.

[0005]

However, in the conventional fuel supply apparatus described above, the fuel discharged from the air pump 2 is supplied to the air-assisted fuel injection valve 1 after passing through the pressure accumulating vessel 8. Therefore, there were the following problems. That is, when the driving of the air pump 2 has just started, such as immediately after the start of the engine, the pressure of the pressurized air discharged from the air pump 2 is not sufficiently increased.
In addition, since there is a large volume of the pressure accumulating container 8, the pressure of the pressurized air supplied to the air-assisted fuel injection valve 1 does not easily rise.

[0006] Therefore, not only is the atomization effect of the fuel by the supply of the pressurized air insufficient, but also the delay in transporting the fuel in the extension pipe 5 becomes extremely large, and a long start-up time is required.
In view of the above-described conventional problems, the present invention supplies the assist air at a stable supply pressure during normal operation of the engine, and the assist air maintained at a sufficient pressure immediately after the engine is started. It is intended to improve the startability by supplying the material.

[0007]

Therefore, the fuel supply device for an internal combustion engine according to the present invention introduces assist air downstream of a fuel injection valve as shown in FIG. A fuel supply device for an internal combustion engine including an air assist fuel injection valve A adapted to inject fuel mixed with assist air, comprising an air pump B communicating with the air assist fuel injection valve A, and discharged from the air pump B Pressurized air supply means D for supplying pressurized air to the air-assisted fuel injection valve A and for supplying to the pressure accumulating space C of the assist air which communicates with the air pump B and which communicates with the air-assisted fuel injection valve A; An engine operation detecting means E for detecting an operation start operation and a stop operation of the engine.
Pressure detecting means F for detecting the pressure in the pressure accumulating space C
And pressurized air supply means for operating the pressurized air supply means D in an engine operation start operation based on a detection signal from the engine operation detection means E and stopping the operation of the pressurized air supply means D in a stop operation. When the pressure in the pressure accumulating space C is less than the set pressure by the operation stop operation of the engine based on the control means G, the detection signal from the engine operation detection means E and the detection signal output from the pressure detection means F, B, and an air pump control means H that stops driving the air pump B when the pressure in the pressure accumulation space C is equal to or higher than a set pressure.

[0008]

In this configuration, when the operation of the engine is stopped,
The driving of the air pump B is continued so that the pressure in the pressure accumulating space C rises to a preset pressure, and the driving of the air pump B is stopped when the pressure in the pressure accumulating space C rises to the preset pressure. I do.

Therefore, at the time of the next engine start, the pressure accumulating space C
The pressurized air sufficiently stored in the fuel injection valve A can be supplied to the air-assist fuel injection valve A, and the supply of the pressurized air can sufficiently atomize the fuel. Since there is no delay in transporting the fuel in the pipe, the engine can be started quickly, and the startability can be improved, such as the start time can be reduced.

Further, during operation of the engine, pressurized air can be supplied to the air-assisted fuel injection valve A at a stable supply pressure, so that the fuel can be atomized reliably, thereby improving combustion, improving fuel efficiency and improving exhaust properties. Can be effectively achieved.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 2 described below, the same elements as those in FIG. 6 are denoted by the same reference numerals, and the description will be simplified. That is, in FIG. 2, an air pump 12 is interposed in an air introduction pipe 11 led from an intake passage upstream of a throttle valve (not shown). The air introduction pipe 11 downstream of the air pump 12 is branched in two directions, and one of the branch pipes 11 </ b> A is connected to an air gallery 14 provided in the air-assisted fuel injection valve 13.

Here, the structure of the air assist fuel injection valve 13 will be described with reference to FIG. In the figure, a fuel injection valve 30 is provided in a main body 13a of the air assist fuel injection valve 13.
Is built in, and on the downstream side of the fuel injection valve 30,
A mixing section 31 for mixing the fuel and the atomized air is provided. The mixing section 31 is provided with a cylindrical body 31A constituting a passage for fuel injected from the fuel injection valve 30, and a large number of injection holes 31a are provided in a peripheral wall of the cylindrical body 31a. Also, the main body 1 of the air assist fuel injection valve 13
An extension tube 29 that branches into two and extends is connected to the tip of 3a. Further, a needle valve type assist air adjusting valve 32 is connected to the peripheral wall of the main body 13a of the air assist fuel injection valve 13. The tip of the assist air adjustment valve 32 is connected to the main body 1 of the air assist fuel injection valve 13.
The fuel injection valve 30 inside 3a communicates with an air passage formed around the mixing section 31, and the air gallery 14 communicates with the rear end.

Therefore, such an air-assisted fuel injection valve 1
In 3, the assist air introduced from the air gallery 14 has its flow rate adjusted by the assist air adjusting valve 32, reaches the inside of the main body 13a of the air assist fuel injection valve 13, and has a large number of injection holes 31a of the cylindrical body 31A. The fuel is jetted and mixed with the fuel jetted from the fuel injection valve 30. And
While passing through the extension pipe 29, the fuel and the assist air are sufficiently mixed, and the intake stroke from the location near the communication port between the intake port 26 and the combustion chamber 27 from the extension pipe 29, that is, from just above the intake valve 28. The fuel is sprayed into the combustion chamber 27 directly in the form of finely atomized fuel.

On the other hand, the branch pipe 11B is connected to the air pump 12
Is connected to a pressure accumulating vessel 15 as a pressure accumulating space C for accumulating pressurized air from the air. A bypass pipe 16 communicating the air introduction pipe 11 on the upstream side of the air pump 12 with the branch pipe 11A;
The bypass pipe 16 is provided with an air regulator 17 for relieving excess air and maintaining a constant pressure in the branch pipe 11A.

Here, the branch pipe 11B is connected to the branch pipe 11B.
An electromagnetic valve 18 for opening and closing B is interposed. Also, the branch pipe 11
An electromagnetic valve 19 that opens and closes the branch pipe 11A is interposed on the upstream side of the communication connection portion of A with the bypass pipe 16. Furthermore,
An electromagnetic valve 20 that opens and closes the bypass pipe 16 is provided upstream of the air regulator 17 of the bypass pipe 16. A control unit 23 connected to the battery 21 via an ignition switch 22 is provided. The control unit 23 includes a CPU, ROM, RA
A microcomputer including an M / A / D converter, an input / output interface, and the like; receiving an input signal from various detection means described later;
2. Control the driving of each solenoid valve 18-20.

That is, an ON / OFF signal from the ignition switch 22 is input to the control unit 23, and an air pressure signal from a pressure sensor 24 as a pressure detecting means F for detecting the pressure in the accumulator 15 and an outside air signal. A temperature signal from the temperature sensor 25 is input. Then, from the control unit 23, an ON / O switch from the ignition switch 22 as the engine operation detecting means E of the present invention for detecting the operation start operation and the stop operation of the engine.
Based on the FF signal, the air pressure signal from the pressure sensor 24, and the temperature signal from the outside air temperature sensor 25, a control signal for controlling the driving of the air pump 12 and the electromagnetic valves 18 to 20 is output.

In the above configuration, the branch pipes 11A and 11A
B containing air introduction pipe 11, air pump 12, and pressure accumulator 1
5 and the electromagnetic valves 18 and 19, pressurized air discharged from the air pump 12 is supplied to the air assist fuel injection valve 13 and communicates with the air pump 12 and the pressure accumulating vessel 15 which communicates with the air assist fuel injection valve 13. The pressurized air supply means D of the present invention for supplying is constituted.

Further, the microcomputer of the control unit 23 activates the pressurized air supply means in the operation start operation of the engine and stops the operation of the pressurized air supply means in the stop operation. The control means and the present invention for driving the air pump 12 when the pressure in the pressure accumulator is lower than the set pressure and stopping the driving of the air pump 12 when the pressure in the pressure accumulator 15 is equal to or higher than the set pressure in the operation stop operation of the engine. And air pump control means.

Next, the drive control of the air pump 12 and the solenoid valves 18 to 20 by the control unit 23 will be described with reference to the time chart of FIG. When the engine is operating, the air pump 12 is driven, and the solenoid valves 18 and 19 are both open.
Pressurized air from the pressure accumulator 15 via the branch pipe 11B.
Is supplied to the fuel injection valve 1 at a stable supply pressure via the branch pipe 11A and the air gallery 14.
3. In the air-assisted fuel injection valve 13, the fuel and the supplied pressurized air are mixed, and this air-mixed fuel is supplied to the extension pipe 29 at the tip of the air-assisted fuel injection valve 13.
, Is supplied directly into the combustion chamber 27 from directly above the intake valve 28 during the intake stroke in the form of finely atomized fuel spray.

When the operation of the engine is stopped, air with a higher pressure than that during normal operation is stored in the pressure accumulator 15 in order to secure high-pressure pressurized air at the time of the next engine start. That is,
If it is detected that the engine has been stopped by the OFF signal of the ignition switch 22, the solenoid valve 19 is closed by the command from the control unit 23, but the solenoid valve 18 is kept open, and The driving of the air pump 12 is also continued. Therefore, the pressurized air from the air pump 12 is supplied and stored in the pressure storage container 15 via the branch pipe 11B, and is not supplied to the air assist fuel injection valve 13. The pressure in the accumulator 15 is detected by the pressure sensor 24, and the opening operation of the electromagnetic valve 18 and the driving of the air pump 12 are continued until the pressure reaches the set pressure. The pressurized air is sufficiently stored in the pressure accumulator 15,
When the pressure in the accumulator 15 becomes equal to or higher than the set pressure, the pressure sensor 24 detects the pressure, and the solenoid valve 18 is closed and the operation of the air pump 12 is stopped by a command from the control unit 23 based on the pressure. Is done.

As shown in FIG. 5, the set pressure in the pressure accumulator 15 when the engine is stopped is set and stored in advance according to the lowest outside air temperature of the day (when the minimum outside air temperature is high, the set pressure is set. The pressure is set small, and when the minimum outside temperature is low, the set pressure is set large.)
The set pressure is read out based on the lowest outside air temperature of the day detected by the electromagnetic valve 18 and the air pump 12 so that the pressure in the accumulator 15 becomes the read set pressure.
Control.

When the ignition switch 22 is turned on at the time of the next engine start, the air pump 12 is driven and the electromagnetic valves 18 and 19 are opened by a command from the control unit 23 based on this ON signal. At this time, the solenoid valve 20 is closed so that the pressurized air in the accumulator 15 is not relieved from the air regulator 17, and the accumulator 1 is detected by the air pressure sensor 24.
When the pressure in the inside of the valve 5 drops to a predetermined pressure, the solenoid valve 20 is opened.

At the time of starting the engine, the pressurized air sufficiently stored in the accumulator 15 immediately after the above-described stop of the engine causes the air-assisted fuel injection valve 13 to be simultaneously cranked with the engine.
Supplied to As described above, when the operation of the engine is stopped, the ignition switch 22 is turned off so that the pressure in the accumulator 15 increases to a preset pressure.
Driving of the air pump 12 and the accumulation vessel 1 from the air pump 12
5 is continued to open the air introduction passage (branch pipe 11 </ b> B), and when the pressure in the pressure accumulating vessel 15 has increased to a preset pressure, the driving of the air pump 12 is stopped and the air pump 12 is moved from the air pump 12 to the pressure accumulating vessel 15. Is closed, the pressurized air sufficiently stored in the accumulator 15 can be supplied to the air-assisted fuel injection valve 13 at the time of the next engine start, and the fine particles of fuel by the supply of the pressurized air can be supplied. As a result, the engine can be started quickly, and the starting time can be shortened, thereby improving the startability.

Further, during operation of the engine, pressurized air can be supplied to the air-assisted fuel injection valve 13 at a stable supply pressure, so that the fuel can be atomized reliably, and the combustion can be improved, and the fuel consumption and exhaust properties can be improved. Can be effectively achieved. Especially,
According to the present embodiment, the set pressure in the accumulator 15 when the engine is stopped is set according to the lowest outside air temperature of the day,
When the minimum outside air temperature is high, the set pressure is set small, and when the minimum outside air temperature is low, the set pressure is set large. Therefore, there are the following advantages.

That is, the fuel atomization at the time of the cold start is promoted, and at the time of cold, the pressure accumulating vessel 15 is cooled and the shrinkage thereof becomes large. On the other hand, when the temperature is warm, the pressure accumulator 15 contracts little, and even if the set pressure is relatively low, a sufficient pressure of the pressurized air can be obtained. Is stopped, the consumption of the driving power of the air pump 12 is suppressed,
By extension, fuel efficiency will be improved.

As described above, the present invention has been described with reference to the specific embodiments. However, the present invention is not limited to these embodiments, and is attached to the present invention by a person skilled in the art. It should be noted that various changes and modifications can be made without departing from the scope of the claims.

[0027]

As described above, according to the fuel supply system for an internal combustion engine of the present invention, during normal operation of the engine, pressurized air can be supplied to the air-assist fuel injection valve at a stable supply pressure, and The air pump is continuously driven so that the pressure in the pressure accumulating space rises to a preset pressure when the operation of the engine is stopped, as well as effectively improving the fuel consumption and improving the fuel consumption and exhaust properties. Then, when the pressure in the pressure accumulating space has been increased to a preset pressure, the driving of the air pump is stopped, so that the next time the engine is started, the compressed air sufficiently stored in the pressure accumulating space is supplied to the air assist fuel. It is possible to supply the fuel to the injection valve, to quickly start the engine, to shorten the starting time, and to improve the startability.

[Brief description of the drawings]

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

FIG. 2 is a system configuration diagram of an embodiment of the above device.

FIG. 3 is a sectional view showing a configuration of an air-assisted fuel injection valve in the embodiment.

FIG. 4 is a time chart for explaining the operation of the embodiment.

FIG. 5 is a characteristic diagram showing a relationship between an outside air temperature and a pressure set in an accumulator in the embodiment.

FIG. 6 is a configuration diagram of a conventional fuel supply device for an internal combustion engine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Air introduction pipe 12 Air pump 13 Air assist fuel injection valve 15 Accumulator 18 Electromagnetic valve 19 Solenoid valve 22 Ignition switch 23 Control unit 24 Pressure sensor 30 Fuel injection valve

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ identification code FI F15B 1/04 F15B 1/04 F16K 31/06 385 (58) Investigated field (Int.Cl. ⁶ , DB name) F02M 69 / 00 F02M 69/04 F02M 69/08 F02D 45/00 F02M 23/12 F15B 1/04 F16K 31/06

Claims (1)

(57) [Claims] A fuel supply system for an internal combustion engine including an air-assisted fuel injection valve that introduces assist air downstream of a fuel injection valve and injects fuel mixed with fuel and assist air from the fuel injection valve. An air pump that communicates with the air assist fuel injection valve, supplies pressurized air discharged from the air pump to the air assist fuel injection valve, communicates with the air pump, and communicates with the air assist fuel injection valve. While providing pressurized air supply means for supplying the accumulating space of assist air to be
An engine operation detecting means for detecting an operation start operation and a stop operation of the engine, a pressure detecting means for detecting a pressure in the pressure accumulating space, and the pressurizing in the engine operation start operation based on a detection signal from the engine operation detecting means. Activate the air supply means, pressurized air supply control means to stop the operation of the pressurized air supply means in the stop operation, the detection signal from the engine operation detection means and the detection signal output from the pressure detection means Air pump control means for driving the air pump when the pressure in the pressure accumulating space is less than the set pressure in the operation stop operation of the engine and stopping the driving of the air pump when the pressure in the pressure accumulating space is equal to or higher than the set pressure. A fuel supply device for an internal combustion engine, comprising: