JPS608088Y2 - Diesel engine decompression device - Google Patents

Description

[Detailed description of the invention] The present invention is a decompression valve that is installed in the valve mechanism of a diesel engine that is particularly small and manually started. The present invention relates to a device, and specifically relates to a device that automates decompression release.

Diesel engines have very high compression pressure, so it takes a lot of force to rotate the crankshaft, making it difficult to start them by hand.

Therefore, in manually started diesel engines, a decompression device is installed in the valve mechanism, and when starting, this decompression device opens the exhaust valve and forcibly reduces the pressure inside the cylinder, making manual rotation of the crankshaft easier. It looks like this.

Then, when the crankshaft rotates sufficiently with the inertia of the flywheel, the decompression device is returned to its original position to release the reduced pressure, thereby highly compressing the air in the cylinder and operating the engine by injecting fuel.

By the way, in the past, decompression release after decompression operation was done manually by checking the rotation of the flywheel, etc., so the timing was inconsistent because it was too early or too late, so decompression was always released at the optimal time. There was a problem that it was difficult to operate the engine.

However, examples of prior art that attempt to solve this problem include Utility Model Application No. 49-32034 and Utility Model Application No. 1977-
No. 66045 [Microfilm (issued by the Patent Office on March 20, 1939 and June 13, 1932)], but the products described in these documents require a forced lubricating oil supply line using a pump. Therefore, the structure is complicated, and it takes time to increase the pressure of the lubricating oil to release the decompression, so there is a drawback that the release is not performed immediately.

The present invention was developed to solve the above-mentioned problems and shortcomings, and includes a delayed return device that uses a fluid restriction on the return side of the decompression lever that performs decompression operation, and this device allows the decompression operation to be carried out at a constant rate. To provide a decompression device for a diesel engine in which a decompression lever is returned after a period of time to release pressure reduction.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, reference numeral 1 is a rocker arm of a valve mechanism, and its approximate center is rotatably fitted to a rocker shaft 2 to form a balance type. An exhaust valve 3 is in contact with one end of the rocker arm 1 that is supported.

A spring retainer 4 is integrally installed on the stem end side of the exhaust valve 3, and a return spring 5 is biased to this retainer 4.

Further, an adjusting screw 6 is screwed onto the opposite side of the rocker arm 1, and a bushing rod 7 from a cam is connected to this screw so as to swing the rocker arm 1 to open and close the exhaust valve 3.

In the decompression device according to the present invention, a decompression adjustment screw 8 is screwed next to the adjustment screw 6 of the rocker arm 1, and a decompression cam 10 having a notch 9 is slidably connected to the screw 8.

A decompression prepper 11 is integrated into the decompression cam 10, and when the lever 11 is tilted to the right side by a link 12, the cam 10 is
By rotating clockwise, the screw 8 contacts the notch 9 and the rocker arm 1 becomes free, and conversely, by tilting the lever 11 to the left and rotating the cam 10 to the left, the screw 8 is pushed out from the notch 9. At this time, the rocker arm 1 is moved to the right side to lower and open the waist exhaust valve 3 regardless of the bushing rod 7, and a delay return device 13 is attached to the right return side of such a decompression prepper 11.

In this delay return device 13, one end of a cylinder 15 containing a piston 14 is attached to a fixed member 16 with a pin 17 so as to be able to rotate up and down, a rod 18 from the piston 14 is connected to the decompression prepper 11, and the piston inside the cylinder 15 is connected to the decompression prepper 11. A return spring 20 is biased between the rod-side cap 14 and the rod-side cap 19.

Further, a connecting fitting 22 having a penetrating hole 21 is attached to the end of the cylinder 15 on the bottle 1 side.
A check valve 23 is provided inside the cylinder of the connecting fitting 2.
A hose 24 from the fuel tank is connected to the hole 21 of No. 2.

The check valve 23 has a funnel-shaped taper 25 formed at the open end of the hole 21, and a ball 26 is housed inside the taper 25, and a part of the taper 25 is always in communication as shown in FIG. A groove 27 is provided, and the ball 26 is held in a predetermined position by a guide 28 so that the ball 26 can open and close the hole 21, and even when the hole 21 is closed, the groove 27 can throttle the fuel and allow it to flow gradually. ing.

Since the present invention is constructed in this way, the decompression prepper 11 is activated by the link 12 during initial excitation of the diesel engine.
When tilted to the left, the rocker arm 1 is swung to the right by the decompression cam 10, the exhaust valve 3 is opened, the pressure inside the cylinder is reduced, and the crankshaft can be easily rotated manually.

On the other hand, at this time, as the decompression prepper 11 falls to the left, the rod 18 of the delay return device 13 is pulled out and the piston 14 moves to the left against the spring 20, and the inside of the cylinder 15 becomes negative pressure and the ball 26 opens the hole 21, thus allowing fuel from the fuel tank to be introduced from the hose 24 through the hole 21 into the cylinder 15.

When you release your hand from the link 12 at a predetermined position, the compression force of the spring 20 immediately acts on the fuel in the cylinder 15 via the piston 14, and the hole 21 is closed by the ball 26, but the inside of the cylinder 15 is closed by the groove 27. By constantly communicating with the hole 21, fuel passes through the groove 27 and is gradually returned by its throttling action.

Then, the rod 18 and the piston 14 sequentially move to the right, and the decompression prepper 11 is returned, and the decompression is released.

After a predetermined period of time has elapsed, most of the fuel in the cylinder 15 has returned and the rod 18 of the piston 14 has moved back into the cylinder 15.
When the decompression prepper 11 returns to its original position and the adjustment screw 8 matches the notch 9 of the decompression cam 10, the rocker arm 1 is separated and the exhaust valve 3 is closed, and the reduced pressure is released and the engine Driving begins.

In addition, when the engine is suddenly stopped, if the decompressor prepper 11 is similarly tilted to the left using the link 12, the pressure inside the cylinder becomes incompressible and the operation stops, and at this time the delay return device 13 operates in the same way. This device 13 causes the decompression prepper 11 to return automatically without any trouble.

The delay time is the spring force of spring 20, groove 27.
A fluid such as lubricating oil or air may be used instead of fuel.

As described above, according to the present invention, the depressurization that is operated when manually starting a diesel engine is automatically released after a certain period of time, so there is no need to release the decompression, and operability is improved. The release timing is no longer too early or too late, improving startability.

In addition, since the decompression device automatically supplies fluid into the cylinder by suction based on the operation of the decompression lever, there is no need to provide a forced fluid supply line using a pump, and therefore, the above-mentioned prior art example does not require a forced fluid supply line. In addition, the structure is simpler than the previous one, and unlike the prior art example in which it takes time for the fluid pressure caused by the pump to rise to the operating pressure, the engine pressure reduction operation can be canceled immediately by checking the intake fluid. Since this is done by returning the lever through a throttle provided in the valve, it is easy to set the time required for the release.

[Brief explanation of drawings]

FIG. 1 is a partially sectional front view showing an embodiment of the device according to the present invention, and FIG. 2 is a partially enlarged sectional view. 1... Tatsuka arm, 3... Exhaust valve, 1
1. Song decompression prepper 13... Delay return device.

Claims (1)

[Scope of utility model registration request] In a decompression device that reduces the pressure inside an engine cylinder by manual operation of a decompression lever, a delay return device is attached to the return side of the decompression lever provided on the opposite side of the valve of the rocker arm, A piston and a check valve are provided for sucking fluid into the cylinder by retreating against an elastic body, and a throttle is attached to the valve, and after the operation, the fluid is immediately returned gradually through the throttle to A decompression device for a diesel engine, characterized in that by returning a lever, the pressure reduction in the cylinder is automatically released after a certain period of time has elapsed.