JPH01224450A - Gas pressure type fuel injection device - Google Patents

Abstract

PURPOSE:To simplify the construction and make it in a small size by controlling the amount of fuel injection with a spring to energize a gauge slider and a pressure control means to control the fuel pressure, and thereby eliminating any actuator otherwise required to adjust the location of the gauge spring. CONSTITUTION:The main part of a fuel injection device is composed of a gauge part 10, an injection part 20 to inject fuel from this gauge part 10 into engine, a fuel line 30 to feed the fuel to the gauge part 10, and a compressed gas line 50 to supply compressed air to the gauge part 10. No.2 valve means 40, 41 are furnished at divergent parts 31b, 32b of the fuel line 30 into a supply line 31 and a return line 32. A No.1 valve means 53 is arranged on a divergent path 50b of the compressed gas line 50. In this constitution, the gauge part 10 is equipped with a spring 17 to energize a gauge slider 12 toward a fuel sump chamber 13. The fuel line 30 is equipped with a pressure control means 42 to control the fuel pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for injecting fuel using gas pressure.

[Prior Art] Gas pressure type fuel injection devices are known from Japanese Patent Laid-Open No. 62-168934 and Japanese Patent Publication No. 60-501963. Specifically, this fuel injection device has a metering section. The metering section includes a body and a metering slider housed within the body. The inside of the boggy is partitioned by a metering slider, and a fuel storage chamber is formed at one end of the slider.

A gas pressure chamber is formed at the other end. Also, weighing slurry,
A gas flow passage is formed in the gas flow passage, and a check valve is disposed in the gas flow passage. Fuel discharged from the fuel reservoir is injected from the injection section.

Further, the fuel injection device includes a fuel system connected to the fuel reservoir chamber of the metering section, and a compressed gas system connected to the gas pressure chamber of the metering section. The compressed gas system is provided with a first valve means for controlling the supply of compressed gas to the metering section, and the fuel system is provided with the above pressure jli.
! A second valve means is provided for closing the feed reservoir when gas is supplied.

In the above configuration, when compressed gas from the compressed gas system is supplied to the gas pressure chamber and the check valve of the metering slider is opened and supplied to the fuel reservoir, the fuel in the fuel reservoir is discharged to the injection section. In addition, fuel is supplied from the fuel system to the fuel reservoir chamber for the injection operation amount. At this time, the position of the metering slider is adjusted by a seven-actuator such as a linear step motor, and the volume of the fuel reservoir chamber is adjusted. As a result, the amount of fuel injected from the fuel reservoir is adjusted.

[Problem to be Solved by the Invention 1] In the above device, since the measuring slider is mechanically displaced using an actuator, the structure of the measuring section becomes large and the cost becomes high.

Furthermore, published patent No. 60-501963 discloses a technique for controlling the fuel injection amount by the length of the opening time using a solenoid valve, but in this case, the injection amount cannot be controlled with high precision. I couldn't do that.

[Means for Solving the Problems] The present invention has been made to solve the above problems, and the gist thereof is that the metering section includes a spring that biases the metering slider toward the fuel reservoir chamber, and the fuel system A gas pressure type fuel injection device is characterized in that it includes a pressure control means for controlling fuel pressure.

[Action 1] Adjust the fuel pressure in the fuel system, and adjust the position of the metering slider where this fuel pressure and the elastic force of the spring are balanced.

Thereby, the volume of the fuel reservoir, in other words, the amount of fuel stored in the fuel reservoir can be adjusted, and the amount of fuel injected when compressed gas is supplied can be adjusted to a desired amount.

[Embodiment 1] Hereinafter, one embodiment of the present invention will be described based on FIGS. 1 and 2. FIG. 1 shows a gas pressure type fuel injection device mounted on, for example, a vehicle. Note that the compressed gas used in this device is compressed air, and the fuel is gasoline.

The gas pressure fuel injection device includes a metering unit 10 (measuring section)
, an injector 20 (injection part) that injects the fuel from the metering unit 10 into the engine cylinder, and a metering unit 22)
a fuel system 30 that circulates fuel to 10 and a metering unit) 1
0 and a compressed gas system 50 for supplying compressed air. The number of metering units 10 and injectors 20 is the same as the number of engine cylinders. Each metering unit 10 is separate from each other and connected to the injector 20 by a relatively short tube.

10 is the body 11 and this body.
11 and a V-shaped measuring slider 12 that is slidably housed within the measuring slider 11. The inside of the body 11 is partitioned into two chambers by this measuring slider 12.
The chamber on one end side of the metering slider 12 becomes a fuel reservoir chamber 13,
The chamber on the other end side is a gas pressure chamber 14. The body 11 is formed with a fuel inlet 13a, a fuel outlet 13b, and a fuel discharge port 13c connected to the fuel reservoir chamber 13, and a gas supply port 14a connected to the gas pressure chamber 14. The metering slider 12 is hollow and has a gas flow passage 15 along the axial direction. This gas flow passage 15 has a check valve]6 at the end on the fuel reservoir chamber 13 side or in the vicinity thereof.
is provided.

A compression spring 17, which is one of the features of the present invention, is accommodated in the gas pressure chamber 14, and the metering slider 12 is biased toward the fuel reservoir chamber 13 by the compression spring 17.

The injector 20 includes a body 21 having a nozzle 21a at its tip, and a nozzle 2 that is slidably supported within the body 21.
1aef1. It includes an outward-opening poppet valve 22 that closes, and a spring 23 that biases the poppet valve 22 in the closing direction. A fuel inlet 21b is formed in the body 21 at the end opposite to the nozzle 21g.
b is a check valve 2 connected to the fuel discharge port 13c of the metering unit 10.
It is connected through 5. As will be described later, when the fuel in the fuel reservoir chamber 13 is pressurized by compressed air and discharged, when it flows into the body 21 of the injector 20 through the check valve 25, it pushes down the poppet valve 22 and 21a is opened, and the fuel is injected into the cylinders of the engine.

The fuel system 30 includes a fuel supply system 31 and a fuel return system 32. The fuel supply system 31 has a main path 31a connected to the tank 36, and a branch path 31b branched from the main path 31a and connected to the fuel inlet 13a of each metering unit 10. Similarly, the fuel return system 32 also has a main path 32a connected to the tank 36, and a branch path 32b branched from the main path 32a and connected to the fuel outlet 13b of each metering unit 10.

The main path 31a of the fuel supply system 31 includes 7 fuel bombs 3.
3 and a filter 34 and an I/NO 7 valve 35 are provided, and when the 7 fuel pump 33 is driven, the fuel in the tank 36 is supplied to the fuel reservoir chamber 13 of the metering unit 10 through the branch path 31b.

Note that the relief pressure of the relief valve 35 is set higher than the fuel pressure during fuel supply, which will be described later.

A branch path 31b of the fuel supply system 31 and the fuel return system 32,
32b each have a normally open pressure-operated shut-off valve 40.4.
1 (second valve means) is provided.

Further, the main path 32a of the fuel return system 32 is provided with an electromagnetic proportional control valve 42 (pressure control means) and a pressure sensor 43, which are one of the features of the present invention.

The compressed gas system 50 includes a main path 50a and a main path 50a.
It is provided with a branch path Sob that branches off from the gas supply port 14a of each metering unit 10 and continues to the gas supply port 14a of each metering unit 10.

The main path 50a has a compressor 51 and a 7-kiemulator 52.
is provided. Each branch path 50b is provided with a normally closed electromagnetic on-off valve 53 (@1 valve means).

The fuel injection device further includes a control unit 60. This control unit 60 receives from the rotation detection device 70 a 7-Alens pulse Re outputted every time the engine crankshaft rotates by 1/2, and an output every time the crankshaft rotates a certain angle, for example, 5 degrees. At the same time, the accelerator position signal Ac from the accelerator sensor 71, the engine cooling water temperature signal Wt from the water temperature sensor 72, and the engine state detection signal E from other engine state detection sensors 73 are input.
g is input. Further, a fuel pressure signal Fp is also input from the pressure sensor 43 mentioned above. The control unit 60 performs calculations based on these input signals and controls the electromagnetic on-off valve 53 and the electromagnetic proportional control valve 42.

As shown in FIG. 2, the control unit 60 includes a target injection timing calculation circuit 61 and a target injection amount calculation circuit 6.
2 is the Ennon rotation speed obtained from the scale pulse Sc,
The target injection timing and target injection amount are calculated based on the accelerator position signal Ac, the cooling water temperature signal Wt, and other engine state detection signals Eg.

The drive pulse generation circuit 63 is the target injection timing calculation circuit 6.
The drive pulses for outputting drive pulses corresponding to the target injection timings from 1 to 1 are selectively sent via the selection switch 64 to the drive circuit 65 of the electromagnetic on-off valve 53 corresponding to each cylinder of the engine.

In addition, in the cylinder discrimination circuit 66, the 7th Allen pulse Re
Based on the scale pulses Sc and Sc, it is determined whether fuel injection should be performed into the cylinder , and the selection switch 64 is operated.

On the other hand, the target pressure calculation circuit 67 calculates the target pressure of fuel based on the target injection amount from the target injection amount calculation circuit 62. The deviation between this target pressure and the actual fuel pressure from the pressure sensor 43 is sent to the duty ratio calculation circuit 68. The duty ratio calculation circuit 68 calculates a duty ratio based on the above deviation so that the actual fuel pressure matches the target pressure, and outputs a drive pulse of this duty ratio to the drive circuit 69 for the electromagnetic proportional control valve 42. .

Next, the operation of the fuel injection device configured as described above will be specifically explained. When the electromagnetic on-off valve 53 of the compressed gas system 50 is opened according to the target injection timing under the control of the Huntroll unit 60, compressed air is supplied to the gas pressure chamber 14, and in response to this pressure, the pressure-operated The on-off valves 40, 41 are closed, and the fuel in the fuel reservoir chamber 13 is confined. The compressed air passes through the gas flow passage 15 in the metering slider 12, opens the check valve 16, and is supplied to the fuel reservoir chamber 13. As a result,
The fuel in the fuel reservoir chamber 13 is discharged from the fuel reservoir chamber 13, passes through the check valve 25, and is injected from the injector 20. In this way, fuel can be injected at the target injection timing corresponding to the engine condition.

When the electromagnetic on-off valve 53 is closed and compressed air is no longer supplied to the gas pressure chamber 14 of the metering unit 10, the pressure-operated on-off valves 40 and 41 open, and the compressed air in the fuel reservoir chamber 13 is released from the 7-well pump 33. The fuel is pushed out to the fuel outlet 13b, and the fuel is supplied to the fuel reservoir chamber 13. The fuel is sucked up from the tank 36 to the 7 fuel pump 33, passes through the fuel storage chamber 13, and is transferred to the tank 3.
It will be returned to 6. At this time, since the fuel flow area is restricted by the electromagnetic proportional control valve 42, the fuel pressure is increased when the fuel pump 33 and the electromagnetic proportional control valve 42 are opened. In the metering section 10, the metering slider 12 is pushed up against the gas spring 17 by this fuel pressure, and fuel is stored in the fuel reservoir chamber 13.

Since the electromagnetic control valve 42 is duty-controlled by the mount roll unit 60 and its throttle area is controlled, the fuel pressure is controlled in accordance with the throttle area. The metering slider 12 of the metering unit 10 comes to rest at a position where the fuel pressure and the elastic force of the spring 17 are balanced. As a result, the volume of the fuel reservoir 13 can be changed according to the fuel pressure, and the amount of fuel injected from the fuel reservoir 13 can be adjusted, thereby achieving a target injection amount corresponding to the engine condition. can.

Note that the metering unit 10 does not have an actuator for adjusting the position of the metering slider 12, and has a simple structure that only has a built-in spring 17, so it can be separated for each number of engine cylinders, and relatively short tubes can be used. It can be connected to the injector 20 via the injector 20. Therefore, the fuel discharge pressure from the metering unit 10 can be made relatively stable, thereby making it possible to stabilize the opening operation of the outward-opening poppet valve 22 and, in turn, stabilize the fuel injection.

The present invention is not limited to the above embodiments, and various embodiments are possible. For example, the above-mentioned measuring unit) 10 and the injector 20
It may also be visualized.

Further, instead of the pressure sensor, a feedback signal may be obtained from a position sensor that detects the position of the metering slider, and the fuel pressure may be controlled so that the metering slider is at the target position. Further, the injection section may simply be a nozzle opening into the intake manifold of the engine.

[Effects of the Invention 1] As explained above, in the present invention, the fuel injection amount can be controlled by the spring that biases the metering slider and the pressure control means that controls the fuel pressure, and there is a mechanism for adjusting the position of the metering spring. Since no actuator is required, the structure can be made smaller and simpler, and manufacturing costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an embodiment of the fuel injection device of the present invention, and FIG. 2 is a circuit block diagram inside the control unit of FIG. 1. DESCRIPTION OF SYMBOLS 10... Measuring part (measuring unit), 11... Body, 12... Measuring slider, 13... Fuel reservoir chamber, 14
... Gas pressure chamber, 15... Gas flow path, 16... Check valve, 17... Spring, 20... Injection part (injector), 30... Fuel system, 40.41.・Second
Valve means (pressure-operated on-off valve). 42... Pressure control means (electromagnetic proportional control valve), 50... Compressed gas system, 53...
・First valve means (electromagnetic on-off valve)

Claims (1)

[Claims] (a) A body and a metering slider housed in the body, in which a fuel storage chamber is formed at one end of the metering slider, and a gas pressure chamber is formed at the pond end. A gas flow passage connecting the gas pressure chamber and the fuel reservoir chamber is formed in the metering slider, and a metering section in which a check valve is disposed in the gas flow passage; (c) a fuel system connected to the fuel reservoir chamber of the metering part; (d)
a compressed gas system connected to the gas pressure chamber of the metering section; (e) a first valve means provided in the compressed gas system for controlling supply of compressed gas to the gas pressure chamber of the metering section; and (f) the fuel In the gas pressure type fuel injection device, the metering section includes a second valve means that is provided in the system and closes the fuel reservoir chamber when compressed gas is supplied to the metering section, and the metering section includes a spring that biases the metering slider toward the fuel reservoir chamber. A gas pressure type fuel injection device, characterized in that the fuel system is equipped with pressure control means for controlling fuel pressure.