JPH0249941A - Fuel supply device for lp gas engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fuel supply system for an LP77' engine, which is particularly improved in terms of startability.
, relates to a fuel supply device for f-suennon.

(Prior art) Conventionally, T = improves the startability of LPM7'Sennon.
As a step, a method of forcibly increasing the fuel supply amount at the time of startup is adopted. For example, Japanese Patent Publication No. 61-9506 discloses a means for detecting engine cranking and a method for detecting engine cranking when the engine temperature is low than a predetermined value. Selectively supplies gas phase fuel,
Above that, in order to selectively supply liquid phase fuel, a fuel switching device that automatically switches the fuel supplied to the vaporizer, and a primary depressurization of the vaporizer when switching to vapor phase fuel by Moeki fuel switching vcrfi and during cranking. An electromagnetic starting fuel increase device nt that forcibly increases the amount of fuel from the chamber to the secondary region Ii chamber and cancels the increase in fuel after cranking is completed.
- A 1-P suction fuel supply system is disclosed.

(The turning point that the invention aims to solve) By the way, even when the ignition switch is turned off to stop the Ennon, the Ennon does not stop immediately, but rotates for a short time due to inertia, and remains in the intake manifold. The mixture is scavenged and then stopped. on the other hand,
When the ignition switch is turned off, fuel is no longer supplied from the vaporizer. Therefore, the above conventional LPf
Even if you forcibly increase the amount of fuel supplied during cranking, such as with a fuel supply system for f-s engines, when starting the dog,
Since there is almost no air-fuel mixture in the flammable range uB remaining in the intake manifold, it is unavoidable that the start of the engine will be delayed, at least until the fuel passes through the intake manifold and reaches the combustion chamber of the engine. Ta.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel supply system for the LrM7 Suennon that can overcome these problems and shorten the time required for starting.

(Means for Solving the Problems) What is the structure of the present invention that meets the above-mentioned objectives and the primary decompression chamber of the vaporizer? A solenoid valve disposed in a slow fuel passage connecting a Jl intermediate to conduct and cut off the slow fuel passage, and a control means for opening the solenoid valve for a certain period of time when the ignition inch is turned off. The main points are as follows.

(Function) According to the above configuration, when the ignition switch is turned off in order to stop the engine, the slow fuel passage is made conductive for a certain period of time, during which time fuel is supplied from the primary decompression chamber to the mixer. Therefore, even if the engine rotates due to inertia and the air-fuel mixture in the intake manifold is scavenged after the ignition switch is turned off, a new air-fuel mixture in the flammable range is formed in the intake manifold after the engine stops. As a result, when the engine is next started, this air-fuel mixture flows into the combustion chamber of the engine, reducing the time required for starting.

(''51 cases) Embodiments of the present invention will be described in detail below based on the drawings.

Figure t51 is an overall configuration diagram showing the fjtJ1 embodiment of the present invention.

In FIG. 1, 1 is a vaporizer, and the central septum n:
! The first room 3 is divided into a primary decompression chamber 6 and a primary pressure regulation chamber 7 by the first guia 7ul-5, and has a densely constructed room 3 and a room 4 divided by 2. room 6
are the LP gas inlet passage 8 and the pipe line 9 formed in the casing 1a.
The conduit 9 is connected to a fuel tank 10 through a filter 11 and a solenoid valve 12 that is closed when the engine is stopped to cut off the fuel supply to the vaporizer 1.

This L
A swing motor (I
The first valve lever 14, which is pivotally supported by E, is recessed. From the fuel tank 10 to the L Pffs inlet passage 8
The liquid L Pffs that has been exposed to the liquid will first be released under its own pressure.
The pulp lever 1t is pushed open and enters the primary decompression chamber 6, where it is vaporized under reduced pressure. - When the pressure in the human decompression chamber 6 reaches a predetermined pressure, the first guide 77 ram 5
It is biased to the left in the figure against the action of the regulator spring 24, and the first valve lever 14 is biased toward the closing side by the first ram 7k 16, thereby blocking the LP7' inflow path 8. Further, when the pressure in the primary decompression chamber 6 decreases due to the tlV cost of fuel, the first valve lever 14 is biased toward the open side, and the LP and FF inflow passages 8 are communicated with each other, and the fuel tank 12
Fuel flows into the primary decompression chamber 6 from there. In this way, the first valve lever 14 keeps the pressure in the primary decompression chamber 6 at a constant predetermined pressure by repeatedly cutting off communication with the LPff gas inflow path 8.

The room 4 is divided into a secondary pressure reduction chamber 18 and one secondary pressure regulation chamber by a PtfJ2Guia7ram 17, and the secondary pressure reduction chamber 18 is connected to the primary pressure reduction chamber 6 by a passage 20 penetrating the central partition wall 2. At the same time, it is connected to a venturi section 31 of the mixer 30 via the main fuel passage 21, so that venturi negative pressure is applied thereto. Further, the passage 20 is swingably supported on a shaft 22 at the side gate of the secondary decompression chamber 18 in order to open and close the passage 20! ￥S2 Pulp Lever 23
is provided and biased towards the closing side by a second regulator spring 24. This second valve lever 23 is activated by the venturi negative pressure exerted on the secondary reduced pressure.
When the Guia 7 ram 17 is biased to the left in the figure, it is biased toward the 111 side via the pressure T25, communicating the passage 20, and is also biased toward the 11 side by the second regulator spring 24. While decompressing the fuel introduced into the secondary decompression chamber 18 from the passage 20 to almost atmospheric pressure and keeping it at a constant pressure, the fuel in the secondary decompression chamber 18 The fuel is sent to the mixer 30 via the main fuel passage 21 by the venturi negative pressure, mixed with intake air there, and supplied to the ennon (not shown) through the intake manifold 33.

The Moeki-secondary pressure regulating chamber 7 is communicated with the secondary decompression chamber 4 through a passage (not shown), and the secondary decompression chamber 4 is exposed to flames through a passage 1b formed in the casing 1a. .

Next, the human decompression chamber 6 is connected to the venturi section 31 of the combinator 30 via the slow fuel passage 26, and the slow fuel passage 26 is connected to the output f of the hunt roll unit 27.
An electromagnetic valve 28 is provided which selectively turns on and off the slow fuel passage 26 under the control of the IR signal.

The starter switch 29u, which is operated when starting the Ennon, the ignition switch 29b, which is operated when igniting the Ennon, and the r-p
A starter inch 29c that is turned on when the throttle valve 32 of the gas mixer 30 is at the idle opening position and turned off when it is not at the idle opening position, and a rotational speed that detects the engine speed and outputs a rotational speed signal. Detection means 29d
and a temperature detection means 29c that detects the temperature of the Ennon cooling water and outputs a temperature signal. The control unit 27 preferably uses a microcomputer operating according to a predetermined program to control hM.
You can r&.

Hereinafter, an example of the control force method when the control 27 is formed using a microcomputer will be explained based on the chart 70 shown in FIG.

First, in step 101, turn on the starter switch 29.
It is determined whether or not a has been operated, and the status inch 2
9a-/)' In case 6, that is, when the ennon is first QJ, in step 113, the solenoid valve 28 is controlled to open at a preset duty ratio A (%). Therefore,
Simultaneously with cranking, fuel is supplied from the primary decompression chamber 6 to the mixer 3 ( ) via the slow fuel passage 26 . By appropriately setting the duty ratio A, an appropriate amount of fuel required for starting is supplied via the slow fuel passage 26.

If the starter switch 29a is off, then in step 102 it is determined whether the ignition switch 29b is on. When the ignition switch 29b is turned off to stop the Ennon, step 1()3
The timer built into the microcomputer is set to the timer, and step 104 (step 104) determines whether there is a timeout or not. The solenoid valve 28 is controlled with a duty ratio of 1'3 F 1311, and when the timeout occurs, the process moves to step 7, the solenoid valve 28 is controlled to open, and the fuel supply is stopped. T and the duty B are set in advance through experiments or the like so that the fuel supplied to the mixer 30 through the slow fuel passage 26 during this period forms an air-fuel mixture in the flammable range in the intake manifold 33. Therefore, after the ignition switch 29b is turned off, even if the engine rotates due to inertia, an air-fuel mixture within the flammable range is formed in the intake manifold 33, so the next time the engine is started, this air-fuel mixture will enter the combustion chamber of the engine. flow, reducing start-up time.

Next, when the 1st ignition switch 29 [+ is on, or when the ennon is ignited, in step 7 step 10G, the ff
The reference starting rotation speed NE thus obtained is compared with the enon rotation speed NE input from the rotation speed detection means 29d as a rotation speed signal. The reference starting rotation speed NE is the standard for determining whether or not the engine has been started normally and has reached the required starting rotation speed. If it is smaller than the quasi-starting rotation failure NE, this means that engine starting has not been completed normally due to some kind of malfunction, and the process moves to step 107, where the solenoid valve 28 is controlled to open and the fuel supply is stopped.

If the ennon rotation speed NE is greater than the base thread starting rotation speed NE and the ennon start is successfully completed, in step 108, it is determined at t4 whether the throttle valve 32 is at the idle 11 degree position. When the indicated accelerator pedal is depressed and the 111 cars start accelerating, the timer is set to time T2 in step 109,
In step 110, it is determined whether or not there is a timeout, and as long as there is no timeout, in step 111, the solenoid valve 28 is controlled to open at the duty ratio C (%), and when time T2 has elapsed, the process moves to step 113 and is controlled to open at the duty ratio A. do. Since the duty ratio C is set to be hotter than the duty ratio A, a large amount of fuel is supplied during acceleration.

When the throttle valve 32 is at the idle opening position 16 and the throttle switch 29c is in the on state, the engine speed/k number NE input as the rotation speed signal in step 112 and the temperature signal input from the temperature detection stage 29e are input as the temperature signal. Based on the coolant temperature T11W, it is determined whether the operating state of the ennon is idling or decelerating. Microcomputer ROM1 is F
The characteristic curve shown in Figure 1 is memorized. Third
The characteristic curve in the figure shows whether the operating state is idling or deceleration driving such as when driving down a long downhill slope based on the engine speed and cooling water temperature. This serves as a standard for classification, and is displayed with the engine rotation number NE in the vertical line and the cooling water temperature T11W in the horizontal line. When the input engine speed NE and cold J'S water temperature T HW are within the region α surrounded by the vertical axis, the horizontal thin line, and the characteristic l1lI line, the engine is in an idling state, When it is present, it indicates that it is in a deceleration operation state.

When the rotational speed NE and the reso coolant temperature HW are outside the range α, that is, during deceleration operation, the process moves to step 107, and the electromagnetic valve 28 is controlled to close, and fuel supply is stopped. - Step 1 when in the force region α, i.e. during idling
13, the solenoid valve 28 is controlled to communicate with the duty ratio C.

In this embodiment, the electromagnetic valve 28 is subjected to duty control, but may be simply on/off controlled.

As explained above, according to the 1st X embodiment, when the ignition switch 29b is turned off to stop the ennon, the solenoid valve 28 is controlled to be open for a certain period of time, and during this period, the fuel is slowed down from the primary decompression chamber 6. through the fuel passage 26 to the mixer 3
Replenished to 0. Therefore, the ignition switch 29b
After the ignition switch 291J is turned off (when the ignition switch 291J is turned off), even if the air-fuel mixture in the intake manifold 33 is returned by rotating due to inertia, the fuel supplied after the ignition switch 291J is turned off (when the ignition switch 291J is turned off) will cause the ignition to fall within the flammable range. 1 is formed, and this air-fuel mixture flows into the combustion chamber of the ennon at the next start, so the time between start ILj is shortened.

Furthermore, since the opening and closing of the solenoid valve 2) 3 that opens and closes the slow fuel passage 26 is controlled by operating the starter switch 29a, fuel is supplied at the same time as cranking, and the starting performance of the LP gas engine can be improved.

Further, based on the outputs of the starter switch 29a, ignition switch 29b, throttle switch 29c, rotation speed detection means 29d, and temperature detection means 21]e, it is automatically determined whether the engine is in an idling operation state or a deceleration operation state. , Solenoid valve 28 during idle operation
The required amount of fuel is supplied by controlling the opening and closing, and during deceleration operation such as when driving on a long slope, the solenoid valve 28 is controlled to close and the supply of fuel rJ (stops. It becomes possible to quickly control fuel supply.

Next, a second embodiment of the present invention is shown in FIG. The first mentioned above
In the embodiment, the control unit 27 consisting of a microcomputer was used as the control means for the solenoid valve 28;
In the second embodiment, instead of this, the solenoid valve 28 is controlled by a drive circuit 10 shown in FIG. ttS4.

In Fig. 1, tl is a battery, 42 is an even sink inch, 43 is a backflow prevention + tJI diode, 4
4 is a resistor, 45 is a capacitor, 46 is a drive coil of electromagnetic #28, and a series circuit of the resistor 44 and capacitor 15 and the drive coil 16 are connected to the battery via an ignition switch 42 and a backflow prevention diode 43. 411 are connected, and the negative side of the pantry 41 is grounded to the body.

According to this drive circuit 40, the ignition switch 1
When 2 is turned on, the capacitor 15 is charged and the drive coil 4G is energized, so that the solenoid valve 28 is darkened and the slow fuel passage 26 is conductive.

Ignition switch = 1 to stop Ennon
2 is turned off, the connection between the buffer battery 41 and the drive coil 46 is cut off, but since the discharge current from the capacitor 45 flows through the drive coil 461, the solenoid valve 28 remains open for a certain period of time T1 after the ignition switch 12 is turned off. During this period, fuel is supplied from the slow fuel passage 26 to the mixer 30. This delay time T1 can be adjusted to I$ by appropriately setting the resistance value of the resistor 14 and the capacitance of the capacitor 45.
1 can be adjusted.

(Effects of the Invention) According to the present invention, a solenoid valve is disposed in the slow fuel passage connecting the primary decompression chamber of the vaporizer and the fJX combiner, and the solenoid valve is operated for a certain period of time after the ignition switch is turned off. Since it is configured to open the engine, when the ignition switch is turned off to stop the Ennon, the 1111 slot fuel passage is turned on for a certain period of time. Fuel to?
I can supply lIl. As a result, after the ignition switch is turned off, the ennon rotates by inertia, scavenging the air-fuel mixture in the intake manifold, and after the ennon stops, a new air-fuel mixture in the flammable range is prepared in the intake manifold, so the time required for starting It becomes possible to shorten the time. 4゜

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram showing the first embodiment of the present invention, Fig. 2 is a flowchart showing the control force method by the control unit of this embodiment, and Fig. 3 is an idling operation and deceleration operation (
FIG. 4 is a configuration diagram of the drive circuit used in the second embodiment of the present invention. Decompression chamber, 26... Slow fuel passage, 27... Control unit (as control means), 28... Solenoid valve,
2911.42...Ignition switch, 30...
- Mixer, 40... drive circuit (as control means).

Claims (1)

[Scope of Claims] A solenoid valve disposed in a slow fuel passage connecting a primary decompression chamber of a vaporizer and a mixer to conduct and cut off the slow fuel passage; 1. A fuel supply device for an LP gas engine, comprising: a control means for opening the fuel.