JPH0235862B2 - ENJINNOKUKISHIKIGABANASOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention adjusts the opening amount of the throttle valve by balancing the operating force of the negative pressure actuator and the tension of the governor spring to maintain the rotational speed of the engine regardless of load fluctuations. This invention relates to a pneumatic governor device that maintains a constant state.

The basic structure of the pneumatic governor device is to operate a negative pressure actuator using the intake negative pressure in the intake passage on the leeward side of the throttle valve, and to balance this negative pressure operating force with the tension of the governor spring.

Then, as the opening area of the throttle valve relative to the opening/closing angle changes in a cosine curve shape X as shown in FIG. It becomes a sinusoidal curve Y as shown in Figure A.

However, as shown in FIG. 3, the governor spring is drawn out in a tangential direction from the midpoint of the swing angle of the throttle lever 25, and the opening tension of the governor spring 26 relative to the closing angle of the throttle valve is As shown in Figure 2B, it changes to a substantially straight line Za.

Therefore, when the engine rotational speed changes, in a region where the throttle valve 25 is close to fully closed, the rate of decrease in the valve-opening tension of the governor spring 26 lags behind the rate of increase in the valve-closing output of the negative pressure actuator 28. This causes a problem in that the throttle valve is biased towards the open side, which increases the rotational speed of the engine, which delays the closing of the throttle valve and deteriorates governor performance.

The present invention was proposed to solve the above problem, and includes a cable provided at the tip of the governor spring, a circumferential cam around which the cable is wound around the circumferential surface of the opening/closing tool of the throttle valve, and the circumferential surface By adjusting the winding amount of the cable with a cam, the output of the governor spring is made to match the output of the negative pressure actuator, which changes with fluctuations in intake negative pressure.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front view showing the structure of a pneumatic governor.

In this pneumatic governor, a mixer 3 and an air cleaner (not shown) are sequentially attached to the intake pipe 2 of a gas engine 1 that uses LPG or city gas as fuel. The governor spring 7 that operates this to the fully open side 6 and the fully closed side 8
A negative pressure actuator 9 is provided which can be operated.

The governor spring has its base end 7a connected to the mixer 3.
It is attached to a bracket 10 attached to the bracket 10 so as to be adjustable in forward and backward movement, and a single cable 11 made of wire extends from the tip end 7b.

A fixture 12 is formed at the tip 11a of the cable 11, and this fixture 12 is connected to a locking portion 5a of an opening/closing device 5 of the throttle valve 4.

The opening/closing device 5 is fixed to the valve shaft 13 of the throttle valve 4, has an output shaft 14 of the negative pressure actuator 9 connected to its lower part, and has a terminal formed at the tip 7b of the governor spring 7 on its upper circumferential surface. A circumferential cam surface 15 is formed around which the cable 11 is wound.

The peripheral cam surface 15 is connected to the output shaft 14 of the negative pressure actuator 9.
The closer the throttle valve 4 is to fully closed, the more the cable 1
The circumferential cam surface 15, the cable 11, and the contact point P are arranged so that the amount of winding of the governor spring 7 is reduced, and the tension of the governor spring 7 acts as a valve opening force on the throttle valve 4 via the opening/closing device 5. The length H of the throttle valve 4 to the valve shaft 13 is formed to gradually decrease.

In addition, a negative pressure actuator 9 that operates the opening/closing device 5 to the fully closed side 8 with its output shaft 14 connects the negative pressure working chamber 16 to the combustion chamber (not shown) from the throttle valve 4 of the intake pipe 2 through the negative pressure introducing pipe 17. It is communicated with the intake passage 18 up to the point .

Next, the operation of the pneumatic governor device configured as described above will be explained.

In normal engine operation, when the valve closing force of the output shaft 14 of the negative pressure actuator 9 due to the negative pressure in the intake pipe 2 is balanced with the valve opening force due to the tension of the governor spring 7, the engine operates as desired. It is rotating at a rotation speed of .

In this state, if the load on the engine suddenly drops, the engine speed tends to increase, increasing the negative pressure in the intake pipe 18.

When the negative pressure in the intake pipe 2 increases, the negative pressure in the negative pressure working chamber 16 also increases, and the output shaft 14 attempts to close the throttle valve 4 via the opening/closing device 5.

At this time, the amount of wrapping of the cable 11 provided at the tip 7b of the governor spring 7 around the circumferential cam surface 15 of the opening/closing tool 5 becomes smaller as the opening/closing tool 5 approaches the fully closed side 8, so the negative pressure actuator 9 The valve-opening force of the governor spring 7 corresponding to the throttle valve-closing force increases only gradually, as shown by the solid line Z in FIG. 2A.

Therefore, the negative pressure actuator 9 quickly swings the throttle valve 4 to the fully closed side 8 to prevent an abnormal increase in the rotational speed of the engine.

If the engine speed drops below the set speed, the valve closing force of the negative pressure actuator 9 and the valve opening force of the governor spring 7 act in the opposite manner to the above, and the engine speed is quickly reduced to the set speed. increase to a number.

Further, in the above embodiment, a gas engine was explained, but a liquid fuel engine may be used, and in this case, the mixer becomes a vaporizer.

As described above, the present invention provides a circumferential cam surface on the circumferential surface of the opening/closing tool that operates the throttle valve, and uses this circumferential cam surface to control the amount of winding in and letting out of the cable provided at the tip of the governor spring. Since the tension of the governor spring is adjusted to match the output of the negative pressure actuator that changes in a curved manner, the valve closing operation of the negative pressure actuator is prevented when the engine speed increases abnormally as described in the conventional example. The rate of decrease in the governor spring's valve-opening tension lags behind the rate of increase in power, biasing the throttle valve toward the opening side and increasing the engine rotational speed, which worsens the responsiveness of the governor and reduces governor performance. This problem can be definitely prevented.

Moreover, the present invention has a simple structure in which a peripheral cam surface for adjusting the amount of winding of the cable provided at the tip of the governor spring is provided on the peripheral surface of the opening/closing tool that opens and closes the throttle valve, making it inexpensive. It can be implemented.

[Brief explanation of drawings]

Fig. 1 is a schematic front view showing the structure of the pneumatic governor of the engine, Fig. 2 A shows the output of the governor spring and negative pressure actuator with respect to the opening angle of the throttle valve, and Fig. 2 B shows the throttle valve opening angle. A graph showing the relationship between the valve opening angle and the intake passage opening area,
FIG. 3 is a diagram corresponding to FIG. 1 showing a conventional example. 1...Engine, 3...Fuel mixture forming device (mixer, carburetor), 4...Throttle valve, 5...Opening/closing tool, 6...Full open side, 7...Governor spring,
7b...Tip of 7, 8...Fully closed side, 9...Negative pressure actuator, 11...Cable, 11a...Tip of 11,
15...peripheral cam surface, 16...9 negative pressure working chamber,
18...Intake path.

Claims (1)

[Claims] 1 A governor spring 7 and a negative pressure actuator 9 are interlocked and connected to the opening/closing device 5 of the throttle valve 4 of the fuel mixture forming device 3 of the engine 1, and the negative pressure actuating chamber 16 of the negative pressure actuator 9 is connected to the throttle valve 4. The opening/closing tool 5 of the throttle valve 4 communicates with the intake passage 18 between the
is configured to be driven to the fully open side 6 by the governor spring 7 and to the fully closed side 8 by the negative pressure actuator 9,
The cable 11 is led out from the tip 7b of the governor spring 7, a circumferential cam surface 15 is formed on the circumferential surface of the opening/closing tool 5, and the cable 11 is wound around the circumferential cam surface 15.
1 is fixed to the opening/closing tool 5, and the conditions are such that the rate of increase in the valve closing force of the governor spring 7 per unit valve closing angle of the throttle valve 4 becomes smaller as the opening/closing tool 5 approaches the fully closed point. A pneumatic governor device for an engine, characterized in that the circumferential cam surface 15 is formed in a satisfactory shape.