JPS6356423B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for improving startability of an LP gas engine.

An LP gas engine is designed to suck LP gas that has been vaporized under reduced pressure by an LPG regulator together with air from a vaporizer (mixer), and the flow rate of the mixture of LP gas and air is controlled by a It is designed to be regulated by a throttle valve.

LP gas engines generally do not have a choke device in their intake systems like gasoline engines do, and for this reason, LP gas engines may not be supplied with a mixture with an appropriate air-fuel ratio when starting cold. However, starting performance is not as good as that of a gasoline engine.

In view of the above points, the idling opening of the throttle valve is increased at the time of starting, and
Startability improvement devices have been devised in the past that improve startability by forcibly opening the secondary valve of an LPG regulator and increasing the amount of fuel to optimize the air-fuel ratio at startup.

However, the conventionally known starting performance improvement device is a manual type, and when it is operated, the idling opening of the throttle valve is increased by a predetermined amount until the operation is canceled. The state in which the secondary valve is forcibly opened is maintained,
For this reason, especially in models that extract liquid-phase fuel from an LPG tank, a large amount of fuel flows from the primary chamber to the secondary chamber of the LPG regulator, causing the mixture supplied to the engine to become overly rich and, on the contrary, Starting performance may become poor. In addition, in the case of a manual startability improvement device, it must be activated manually when cranking the engine, and it must be deactivated manually after the engine has started, which requires complicated operations. I need. Furthermore, if the startability improving device is activated even after the engine has been started due to forgetting to release it, the air-fuel ratio after the engine has been started will be incorrect, causing problems such as deterioration of drivability and an increase in harmful components in the exhaust gas.

An object of the present invention is to provide a startability improvement device for an LP gas engine that automatically operates when the engine is started, optimizes the air-fuel ratio at that time, and improves the startability of the engine. .

According to the present invention, this purpose is to drive both the secondary valve of the LPG regulator and the throttle valve of the vaporizer in the valve opening direction by introducing negative pressure into the diaphragm chamber, thereby introducing atmospheric pressure into the diaphragm chamber. A diaphragm device that drives both the secondary valve and the throttle valve in the closing direction by being introduced, and a diaphragm device that connects the diaphragm chamber to an intake pipe outlet port when energized and takes out atmospheric pressure from the diaphragm chamber when not energized. An LP comprising an electromagnetic switching valve connected to the port, and a power supply circuit including a starting switch, which energizes the electromagnetic switching valve when the starting switch is closed, and stops energizing the electromagnetic switching valve when the starting switch is open. This is achieved by a gas engine startability improvement device.

According to this configuration, when the start switch is closed, that is, when the engine is cranking,
Intake pipe negative pressure is introduced into the diaphragm chamber, and since this intake pipe negative pressure is a pulsating negative pressure,
Both the secondary valve and the throttle valve of the LPG regulator repeatedly open and close in response to the pulsation, and as a result, during cranking, a relatively large amount of air-fuel mixture whose air-fuel ratio changes repeatedly and periodically is supplied. As a result, among the air-fuel mixtures whose air-fuel ratios change as described above, the initial explosion is started with the air-fuel mixtures whose air-fuel ratios are suitable for the ignition conditions at this time, and the startability of the engine is improved. The air-fuel ratio of the mixture that explodes for the first time during cranking changes depending on the temperature conditions at that time, so if the air-fuel ratio changes repeatedly and periodically as described above, the air-fuel ratio that can cause the first explosion will inevitably occur within the range of change. This results in a more reliable air-fuel mixture at all times than in the case where the air-fuel ratio of the air-fuel mixture is constant.

When the start switch is opened, that is, when cranking is completed, atmospheric pressure is introduced into the diaphragm chamber, so at this time both the secondary valve and throttle valve of the LPG regulator close, which causes the engine to shut down during idling. It is possible to avoid a situation in which the idling performance deteriorates or becomes unstable due to the continued supply of a large amount of rich air-fuel mixture.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings.

The attached figure is a schematic configuration diagram showing the intake system of an LP gas engine equipped with the startability improving device according to the present invention. In the figure, reference numeral 1 indicates a carburetor for an LP gas engine, and a vent lily 3 is disposed in an intake passage 2 passing through the carburetor, and a throttle valve 4 is shafted downstream of the vent lily. It is provided in such a manner that it can rotate about 5 as a fulcrum.
A lever 33 for setting the idling opening degree of the throttle valve 4 is attached to the shaft 5. The carburetor 1 also has a fuel port 6 that opens at the throat of the bench lily 3.
LP is vaporized under reduced pressure in LPG regulator 7.
Gas is adapted to be supplied via conduit 8. Further, the carburetor 1 has an adjusting screw 9 for adjusting the flow rate of LP gas flowing into the intake passage 2 from the fuel port 6.

The LPG regulator has a primary chamber 12 defined by its casing 10 and a first diaphragm 11, which has a fuel intake port 1 from an LPG tank (not shown).
The liquid phase LP fuel supplied to the primary valve 15 is selectively introduced according to the opening and closing of the primary valve 15. The primary valve 15 is carried on one end of the lever 16. The lever 16 is connected to the casing 1 by means of a shaft 17.
0 and adapted to selectively engage a hook 18 attached to the first diaphragm 11 at the other end. The primary valve 15 is pushed open by the LP fuel supplied to the fuel intake port 14 when the pressure in the primary chamber 12 is below a predetermined value.
On the other hand, when the pressure in the primary chamber 12 exceeds a predetermined value, the diaphragm 11 moves downward in the figure against the spring force of the compression coil spring 19, and the hook 18 closes the valve. It is designed to be driven in the direction. Primary valve 15 as described above
The LP fuel introduced into the primary chamber 12 by opening and closing is vaporized under reduced pressure.

Also, the LPG regulator 7 has its casing 1
It has a secondary chamber 21 defined by a second diaphragm 20 and a second diaphragm 20, and the LP gas in the primary chamber 12 passes through a passage 22 to the secondary valve 2.
It is designed to be introduced according to the opening and closing of 3.
The secondary chamber 21 includes a fuel extraction port 28 and the conduit 8.
It communicates with the fuel port 6 of the carburetor 1 through the.
Further, the second diaphragm 20 defines an atmosphere open chamber 32 on the opposite side from the secondary chamber 21, and the second diaphragm 20
1 and the atmosphere open chamber 32. Secondary valve 23 is carried on one end of lever 24. The lever 24 is pivoted on the casing 10 by a pivot 25 and rests at its other end on an engagement element 26 attached to the second diaphragm 20 .

When the pressure in the secondary chamber 21 is below atmospheric pressure (negative pressure), the second diaphragm 20 moves downward in the figure, thereby causing the lever 24 to move against the compression coil spring 2.
7 in the clockwise direction in the figure, the secondary valve 23 opens. On the other hand, secondary room 2
1 is under atmospheric pressure or higher positive pressure, the lever 24 is rotated counterclockwise in the figure by a compression coil spring 27, thereby closing the secondary valve 23. . In the secondary chamber 21 by opening and closing the secondary valve 23 as described above,
The LP gas is depressurized to almost atmospheric pressure. Further, the casing 10 is provided with a slow fuel take-out port 29 for taking out the LP gas in the primary chamber 12, and this slow fuel take-out port 29 is connected to the conduit 8 via a conduit 30. The flow rate of the LP gas flowing out from the slow fuel extraction port 29 is adjusted by an adjusting screw 31.

The casing 10 also pivotally supports a lever 36 via a pivot 35. The lever 36 engages the second diaphragm 2 with an engaging pin 37 provided at one end thereof.
0 can be selectively engaged. The lever 36 also engages at its other end a lever 39 attached to the casing 10 by a pivot 38. When the lever 39 is rotated counterclockwise in the figure from the position shown, the lever 36 rotates counterclockwise against the action of the compression coil spring 40 and engages the engagement pin 37. The second diaphragm 20 is forcibly moved downward in the figure. That is, the secondary valve 23 is forcibly opened.

The levers 33 and 39 are each connected to the Bowden cable 4.
1 and 42 to an actuating rod 44 of a diaphragm device 43. The rod 44 is supported by a diaphragm 45, and when negative pressure is introduced into the diaphragm 46, it moves to the right in the figure against the action of a compression coil spring 47, and moves the levers 33 and 39, respectively. It is designed to be driven counterclockwise. Diaphragm chamber 46
is the intake pipe negative pressure extraction port 5 provided in the carburetor 1 via the conduit 48, the electromagnetic switching valve 49, and the conduit 50.
Connected to 1. The electromagnetic switching valve 49 connects the conduits 48 and 50 when the electromagnetic coil 52 thereof is energized, and connects the conduit 48 to the atmospheric port 53 when the electromagnetic coil 52 is not energized. It's starting to connect. Current is selectively supplied to the electromagnetic coil 52 from a battery power source 54 via an ignition switch 55 and a starter switch 56.

That is, when the starting switch 56 is closed together with the ignition coil 55, the electromagnetic coil 5
When the start switch 56 is opened, the electromagnetic coil 52 is de-energized.

During engine cranking, both the ignition switch 55 and the start switch 56 are closed, thereby energizing the electromagnetic coil 52 and connecting the conduits 48 and 50. Therefore, during engine cranking, cranking negative pressure, which is a pulsating negative pressure appearing at the intake pipe negative pressure outlet port 51, is introduced into the diaphragm chamber 46. For this reason, the lever 33
and 39 rotate repeatedly and periodically in response to the pulsations of the cranking negative pressure. As a result, the idling opening degree of the throttle valve 4 increases and decreases repeatedly in accordance with the pulsations of the cranking negative pressure, and the secondary valve 23 repeatedly opens and closes in synchronization with this. As a result, the carburetor 1 creates an air-fuel mixture whose air-fuel ratio periodically changes in response to the pulsations, which is not shown in the figure.
Started supplying LP gas to engines.

In this case, among the air-fuel mixtures whose air-fuel ratios change periodically as described above, the initial explosion is started with an air-fuel mixture whose air-fuel ratios are suitable for the ignition conditions at this time, and this causes the LP gas engine to Compared to the case where the air-fuel ratio of the supplied air-fuel mixture is constant, cranking can be performed more reliably at all times.

After cranking the engine, start switch 56
When opened, the electromagnetic coil 52 is de-energized and the conduit 48 is connected to the atmospheric air intake port 53. Therefore, atmospheric pressure is introduced into the diaphragm chamber 46, the levers 33 and 39 are returned to their original positions, the idling opening of the throttle valve 4 becomes the normal opening, and the secondary valve 23 is the secondary chamber 21 and the atmosphere opening chamber 3
It will open and close depending on the pressure difference between the valve and the valve 2, and the amount of fuel will not be increased.

In addition, the lever 36 is moved by the engagement pin 3 as the temperature rises.
7 may be made of a bimetal that deforms in a direction away from the diaphragm 20. In this case, the amount of opening of the secondary valve 23 when it is forcibly opened is adjusted according to the temperature, and the fuel increase is controlled according to the temperature, which further improves engine cooling. drivability will be improved.

In the above, the present invention has been described in detail with respect to specific embodiments, but it will be understood by those skilled in the art that the present invention is not limited thereto and that various embodiments can be made within the scope of the present invention. It should be obvious.

[Brief explanation of the drawing]

The attached figure is a schematic configuration diagram showing the intake system of an LP gas engine equipped with the startability improving device according to the present invention. 1 - carburetor, 2 - intake passage, 3 - bench lily,
4 - Throttle valve, 5 - Shaft, 6 - Fuel port, 7 - LPG regulator, 8 - Conduit, 9 - Adjustment screw, 10 - Casing, 11 - First diaphragm, 12 - Primary chamber, 13 - Conduit ,
14-Fuel intake port, 15-Primary valve, 16-Lever, 17-Pivot, 18-Hook, 19-Compression coil spring, 20-Second diaphragm, 21-Secondary chamber, 22-Passage, 23-Second Next valve, 24 - Lever, 25 - Pivot, 26 - Engagement element, 27 - Compression coil spring, 28 - Fuel extraction port, 29 - Slow fuel extraction port, 30 - Conduit, 31 - Adjustment screw, 32 - Atmosphere Open room, 33~lever, 3
5 ~ Pivot, 36 ~ Lever, 37 ~ Engagement pin, 38
~ Pivot, 39 ~ Lever, 40 ~ Compression coil spring,
41, 42 ~ Bowden cable, 43 ~ diaphragm device, 44 ~ rod, 45 ~ diaphragm,
46 ~ diaphragm chamber, 47 ~ compression coil spring,
48~conduit, 49~electromagnetic switching valve, 50~conduit, 5
1 ~ Intake pipe negative pressure extraction port, 52 ~ Electromagnetic coil,
53~Atmospheric port, 54~Battery power supply, 55~
Ignition switch, 56 ~ Start switch.

Claims (1)

[Claims] 1 By introducing negative pressure into the diaphragm chamber, both the secondary valve of the LPG regulator and the throttle valve of the vaporizer are driven in the valve opening direction, and by introducing atmospheric pressure into the diaphragm chamber, the secondary valve and a diaphragm device that drives both the throttle valve and the throttle valve in the valve closing direction; and an electromagnetic switching valve that connects the diaphragm chamber to an intake pipe outlet port when energized and connects the diaphragm chamber to an atmospheric pressure outlet port when not energized; An apparatus for improving startability of an LP gas engine, comprising a power supply circuit including a starting switch, which energizes the electromagnetic switching valve when the starting switch is closed, and stops energizing the electromagnetic switching valve when the starting switch is opened.