JPH06213078A - Gas fuel supply system of engine - Google Patents

Abstract

PURPOSE:To facilitate the setup of a mechanism, controlling a fuel supply according to an engine driving state and a mixture air-fuel ratio, in an engine room that holds it solidly on a basic assembly consisting of a regulator, a fuel passage and mixer. CONSTITUTION:A pressure regulating spring 10 subject to load control by an actuator 11 is made to act on a membrane 6 of a regulator 1 which adjusts a flow of gas fuel to be entered into a pressure regulating chamber 3 from an inlet chamber 2 to the specified pressure by means of an on-off valve 7. On the basis of each signal out of four engine driving state detecting means 27, 28, 29, 30 and further an air-fuel ratio detecting means 31, a drive signal is transmitted to the actuator 11 from an electronic control unit 32, controlling the load of the pressure regulating spring 10 and altering the extent of opening or closing force of the on-off valve 7, and fuel pressure in the pressure regulating chamber 3 is controlled so as to feed a mixer 25 with a specified supply of the gas fuel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for supplying a gaseous fuel such as LPG or CNG to an engine, and more specifically, a regulator having a function of controlling a fuel supply amount in accordance with an operating condition of the engine and a mixture or exhaust gas condition. The present invention relates to a gas fuel supply device provided in the.

[0002]

2. Description of the Related Art In a device in which a gaseous fuel is adjusted to a predetermined pressure of about atmospheric pressure by a regulator, sucked into a mixer by a negative pressure of an intake air flow, mixed with air and supplied to an engine, the fuel flowing from the regulator to the mixer In addition to adjusting the basic flow rate of (1) by a manual adjustment valve, it is known that the fuel flow rate is adjusted by a control valve driven by an actuator that operates according to the engine operating state and exhaust state.

That is, referring to FIGS. 2 and 3, the regulator 5
In the case where the manual adjusting valve 55 is provided in the fuel passage 54 from the first pressure adjusting chamber 53 to the mixer 62, based on the oxygen concentration in the exhaust gas of the engine 64 detected by the oxygen sensor 65 as shown in FIG. A drive signal is sent from the electronic control unit 66 to the actuator 56 composed of a solenoid, and the flow rate of the correction fuel sent from the inlet chamber 52 of the regulator 51 through the correction fuel passage 58 to the intake pipe 63 from the control valve 57 is feedback-controlled ( (See Japanese Laid-Open Patent Publication No. 54-91624), or as shown in FIG. 3, a negative pressure of the intake pipe 63 is applied to an actuator 59 composed of a diaphragm, and a correction fuel passage is provided in the fuel passage 54 by bypassing the adjusting valve 55. It is known that the control valve 60 of 61 is closed during high speed operation of the engine 64.

As can be seen from these, the actuators 56, 59 and the control valves 57, 60 for controlling the fuel flow rate.
Also, the correction fuel passages 58 and 61 provided with these are necessary as correction components in addition to the basic components of the regulator 51, the fuel passage 54, and the mixer 62, and the number of components is large and especially in a narrow engine room of an automobile. Layout is difficult when installed in

Further, when a gasoline automobile is modified into a gas fuel automobile, the layout and the assembling work become more difficult because the above-mentioned parts are incorporated into the engine room later.

[0006]

SUMMARY OF THE INVENTION The problem to be solved by the present invention is that a correcting component for controlling the fuel supply amount in accordance with the engine operating condition and the mixture or exhaust condition is separated from the basic component. Since it has many parts, it is not easy to install in the engine room.

[0007]

In order to solve the above problems, the present invention relates to an inlet chamber into which gaseous fuel is introduced, a pressure regulating chamber for feeding gaseous fuel adjusted to a predetermined pressure to a mixer, and a passage connecting these chambers. A pressure regulator that acts on the membrane to act in the valve opening direction with respect to the on-off valve provided in a regulator having an on-off valve that interlocks with the movement of the membrane that separates the pressure regulation chamber and the atmospheric chamber to open and close An electric actuator for adjusting the spring and its load, an engine operating state detection means,
An electronic control device for sending a drive signal to the actuator so as to adjust the load of the pressure regulating spring based on a signal from the detection means.

In addition to the above, an air-fuel ratio detecting means for the air-fuel mixture is provided, and a drive signal is sent from the control device to the actuator based on the signal from this detecting means and the signal from the engine operating state detecting means. did.

In general, LPG is used as the gaseous fuel. In this case, the inlet chamber of the regulator also called vaporizer is a primary chamber for reducing LPG to a pressure of about 0.3 Kg / cm ² , and the pressure regulating chamber is LPG. It is a secondary chamber that is further depressurized to a pressure of about atmospheric pressure. Also, the actuator uses a linear stepping motor or a proportional solenoid.

[0010]

[Operation] throttle valve opening, suction pipe negative pressure, engine speed,
The load of the pressure regulating spring is changed according to the operating state of the engine such as the engine temperature to make the on-off valve easy or difficult to open to adjust the gaseous fuel pressure in the pressure regulating chamber to control the fuel supply amount. Further, the fuel supply amount is similarly feedback-controlled according to the air-fuel ratio of the air-fuel mixture or the exhaust gas.

Since the pressure adjusting spring and the actuator, which are the compensating components, are provided in the regulator and there are no components separate from the basic components, the purpose of facilitating the installation in the engine room is achieved. It will be.

[0012]

FIG. 1 shows an embodiment of the present invention.
The regulator 1 includes an inlet chamber 2 into which the gaseous fuel is introduced and a pressure regulating chamber 3 that sends the gaseous fuel adjusted to a predetermined pressure to the mixer 25.
There is an opening / closing valve 7 that opens and closes the passage 4 in conjunction with a passage 4 that connects them and a membrane 6 that divides the pressure adjusting chamber 3 and the atmosphere chamber 5. That is, the on-off valve 7 is attached to the tip of the lever 9 which is freely rotatably incorporated in the pressure adjusting chamber 3 and on which the valve closing spring 8 acts, and the base end of the lever 9 is engaged with the central portion of the membrane 6. It operates in accordance with the displacement of the membrane 6 such that the valve opens when the fuel pressure in the pressure regulating chamber 3 becomes lower than the set value and closes when the fuel pressure becomes higher than the set value, which is exactly the same as the conventional one.

The pressure adjusting chamber 3 is connected to a mixer 25 installed in an intake pipe 24 of an engine 23 by a fuel passage 22 having a manual adjusting valve 21, and the intake pipe 24 has a throttle valve opening sensor 27 and a negative pressure. A sensor 28, an engine 23, a rotation speed sensor 29, and a temperature sensor 30 are attached to the exhaust pipe 26, and an oxygen sensor 31 is attached to the exhaust pipe 26. Electric signals generated by these sensors are input to an electronic control unit 32.

A pressure adjusting spring 10 made of a coil spring built in the atmosphere chamber 5 is brought into contact with the central portion of the membrane 6, and a spring receiver 12 is attached to an output shaft of a linear stepping motor 11 which reciprocates linearly. The pressure regulating spring 10 is compressed or expanded. That is, when the spring bridge 12 advances and approaches the membrane 6, the pressure regulating spring 1
0 makes it easy to open the on-off valve 7, and when it moves backward and moves away from the membrane 6, the pressure adjusting spring 10 expands to make it difficult to open the on-off valve 7. In the former case, a large amount of gas is introduced from the inlet chamber 2. The gaseous fuel is introduced to increase the fuel pressure in the pressure regulating chamber 3 and consequently increase the fuel flow rate sent to the mixer 25, and in the latter case, decrease the fuel flow rate.

The drive signal for the actuator 11 is sent from the controller 32, and the throttle valve opening sensor 27,
Negative pressure sensor 28, rotation speed sensor 29, temperature sensor 30
The load of the pressure regulating spring 10 is adjusted so that an appropriate amount of gaseous fuel corresponding to the operating state of the engine detected by the engine is supplied.

Further, in addition to the electric signal from the sensor, an electric signal corresponding to the oxygen concentration of the air-fuel mixture detected by the oxygen sensor 31, that is, an electric signal corresponding to the air-fuel ratio is input to the control device 32 so that the fuel pressure in the pressure regulating chamber 3 is changed. The air-fuel mixture is set to the stoichiometric air-fuel ratio by performing the feedback control for correction. In this case, instead of the oxygen sensor 31, a sensor for detecting the excess air ratio of the air-fuel mixture may be attached to the intake pipe 24 to detect the air-fuel ratio and perform feedback control.

In this embodiment, since the actuator 11 is attached to the atmosphere chamber cover 13 of the regulator 1 and there is no correction fuel passage with a control valve, the number of parts is small and the regulator 1 and the fuel are substantially used. Passage 22,
It can be easily installed in the same space as when only the basic parts of the mixer 25 are used.

The control device 32 sends a drive signal to the actuator 11 so as to increase the starting fuel amount according to the engine temperature when the starter signal is detected at the time of starting the engine, and an abnormal value is detected in the electric signal from each sensor. When detected, a drive signal is sent to the regulator 11 so as to keep the fuel pressure in the pressure regulation chamber 3 at a preset standard value.

[0019]

According to the present invention, since the means for controlling the fuel supply amount according to the operating state of the engine and the air-fuel ratio of the air-fuel mixture are the pressure adjusting spring and the actuator provided in the regulator, they are separate parts. The structure is simple and the entire structure is small, so that it can be easily installed and installed in a narrow engine room of an automobile.

Further, since the pressure regulating chamber of the regulator has a pressure of about atmospheric pressure, a small load pressure regulating spring is used. Therefore, a compact and low-power actuator is used to provide a wide range of fuel supply with excellent adaptability. It can be easily controlled to an appropriate value.

[Brief description of drawings]

FIG. 1 is a sectional layout view showing an embodiment of the present invention.

FIG. 2 is a layout diagram of a conventional example.

FIG. 3 is a layout view of another conventional example.

[Explanation of symbols]

1 regulator, 2 inlet chamber, 3 pressure regulating chamber, 4
Passage, 5 atmosphere chamber, 6 membrane, 7 open / close valve, 1
0 pressure regulating spring, 11 actuator, 22 fuel passage, 23 engine, 25 mixer, 32 control device,

Claims (2)

[Claims] 1. An inlet chamber into which a gaseous fuel is introduced, a pressure regulating chamber for feeding a gaseous fuel adjusted to a predetermined pressure to a mixer, and a passage connecting the pressure regulating chamber are opened and closed to separate the pressure regulating chamber from the atmospheric chamber. A regulator having an opening / closing valve that works in tandem with the movement of the membrane, an electric actuator for adjusting the pressure adjusting spring acting on the membrane so as to act in the valve opening direction with respect to the opening / closing valve, and its load, and an engine Gas for an engine, comprising: an operating state detection means; and an electronic control device that sends a drive signal to the actuator so as to adjust the load of the pressure regulating spring based on a signal from the detection means. Fuel supply device. 2. In addition to the configuration according to claim 1, the air-fuel ratio detecting means for air-fuel mixture is provided, and the control device is controlled based on a signal from the detecting means and a signal from the operating state detecting means of the engine. A gaseous fuel supply system for an engine, characterized in that a drive signal is sent to the actuator.