JPH04121426A - Air governor device of gasoline engine - Google Patents

Abstract

PURPOSE:To operate arm air governor only at the time of high speed operation of an engine by introducing dynamic pressure and static pressure into two cylinder chambers partitioned by a stabilizer piston, and operating the stabilizer piston by means of a differential pressure of both pressures. CONSTITUTION:An air governor 20 is made up of a cylinder 5, an air governor throttle valve 6, a piston rod 7, and a stabilizer piston 8, on which governor 20 a cam 9, a plate spring 10, and a coil spring 11 are arranged through an air governor valve shaft 21. A dynamic pressure intake port 3 is arranged in an intake passage 17 perpendicularly to an axis of the passage 17, and dynamic pressure of air intaken therefrom is introduced into a right chamber 23 of the stabilizer piston 8. Static pressure in the intake passage 17 is intaken from a static intake port 4, and introduced into a left chamber 22 of the stabilizer piston 8. When an engine is under a maximum control rotation condition and a difference between the dynamic pressure and the static pressure is larger than an energizing force of the coil spring 11, the governor valve 6 is moved in a closing direction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an air governor used as a speed governor for a gasoline engine mainly used in an industrial vehicle such as a forklift.

[Conventional technology]

Most air governors for gasoline engines used in conventional industrial vehicles such as forklifts are installed downstream of a carburetor to control the maximum rotational speed of the engine.

An example of this is shown in FIGS. 6 and 7. As shown in FIG. 6, an air governor 20 is disposed downstream of the throttle valve 2 of the carburetor 1, and this includes an air governor hull, a piston rod 7, a stabilizer piston, and an air governor 20. 8, and is connected to a cam 9 shown in FIG. 7 by an air governor valve shaft 21. The coil spring 11 always urges the air governor valve 6 to the open position via the leaf spring 10, the cam 9, and the air governor valve shaft 21. While the engine is running,
The negative pressure generated in the intake passage 17 passes through the vacuum boat, and in FIG.
The air governor valve 6 is opened and closed by the balance between the force generated by the differential pressure between the negative pressure entering the chamber 22 and the atmospheric pressure entering the right chamber 23 of the piston 8 from the air boat 19, and the biasing force of the coil spring 11. It will be done. (Jitsukai 64-1133
4, Japanese Patent Application No. 2-153973) The operation of the air governor valve 6 of the above-mentioned conventional air governor 20 will be explained below with reference to FIG.

i) When the engine is stopped: As shown in FIG. 8(a), when the engine is stopped, the carburetor throttle valve 2 is fully closed and the air governor throttle valve is fully opened due to the tension of the coil spring 11 (FIG. 7).

11) When the engine is idling: When the engine is started and the engine is idling, the 8th
As shown in Figure (b), although the throttle valve 2 opens slightly, the amount of intake air is small, so the negative pressure P2 in the intake passage 17 downstream of the throttle valve 2 increases due to the intake action of the engine, and this negative pressure P2 and atmospheric pressure P. Difference with POP2
becomes larger than the tension of the coil spring 11, the stabilizer piston 8 moves to the left in the drawing, and the air governor valve 6 is almost closed.

[City] When the engine is at medium speed: Next, when the engine is at medium speed, when the accelerator pedal is depressed to open the carburetor throttle valve 2 as shown in FIG.
2 becomes smaller, the pressure difference (PO-Pg) before and after the stabilizer piston 8 decreases, the tension of the coil spring 11 becomes stronger, and the air governor valve 6 begins to gradually open and the engine speed increases.

iv) When the engine is at high speed: As the engine speed increases, the air governor valve opens further and becomes fully open, allowing operation to continue. If the load suddenly becomes light, and the engine speed increases rapidly, the air-fuel mixture flow speed increases, and the suction effect from the vacuum boat 18 becomes stronger, causing the stabilizer piston 8 to The negative pressure in the left ventricle 22 increases, (P, -P,) increases, the air governor valve 6 moves in the closing direction against the biasing force of the coil spring 11, and further, the air governor valve 6 rotates. center(
The air governor shaft 21) is installed eccentrically with respect to the valve 6, and as the air-fuel mixture with a high flow rate collides with the face of the valve 6, a moment acts on the valve 6 in the direction of closing.
Due to these actions, the air governor valve 6 is closed and the maximum rotational speed is controlled. In this way, the engine's no load maximum rotation (NMR, No Load Max R
evolution) is controlled. Figure 8(d)
shows the state at this time.

FIG. 5 shows an engine rotational speed-governor valve opening diagram from the start of the engine to the maximum no-load rotation (NMR) state when the carburetor throttle valve 2 is fully opened. In the figure, ■→[F] is when starting (S), ■→
0 indicates medium speed, O→◎→[F] indicates medium high speed, and [F] indicates maximum no-load rotation (NMR).

In this way, in this mechanism, there are two times when the governor valve opening is fully closed: ■ and [F].

[Problem to be solved by the invention]

As described above, in the conventional air governor valve, the governor valve closes once when the engine is started, which obstructs the flow of intake air and makes it difficult to start the engine. In addition, the governor valve (flat or closed state) (5th
When you step on the accelerator pedal and suddenly open the carburetor throttle valve from a light load low-medium speed range (B), which is between 0 and 0 in the diagram, the governor valve responds late and opens slowly (because Response is poor and acceleration performance is adversely affected.

As mentioned above, closing the governor valve at startup is a completely unnecessary operation in view of the original purpose of the governor valve, and in fact, in view of the fact that this causes various disadvantages as described above, the present invention provides the following: It is an object of the present invention to provide an air governor operating mechanism that improves the conventional mechanism described above and operates only at a predetermined high rotational speed of the engine.

[Means to solve the problem]

In order to achieve the above object, in the present invention, an air governor throttle valve is disposed downstream of the capplex throttle valve, and the air governor throttle valve is equipped with a coil spring that always urges the valve to the open position. The gasoline engine is equipped with a piston rod connected to a stabilizer piston that operates by sensing the pressure in the intake passage on the downstream side of the carburetor throttle valve to rotate the air governor device/torque valve to adjust its opening. In the air governor device, in the cylinder in which the stabilizer piston fits and slides, two cylinder chambers partitioned by the stabilizer piston,
An air governor device for a gasoline engine, characterized in that the stabilizer piston is configured to take in the dynamic pressure and static pressure of the intake air flow in the intake passage, and operate the stabilizer piston by sensing the differential pressure between the two pressures. provide.

[For production]

When starting the engine and operating at medium to low speeds, the differential pressure between the dynamic pressure and the static pressure is weak. Due to the lack of power, the air governor device and torque valve did not close and remained fully open. As the engine speed increases and enters the high-speed operating range, the dynamic pressure (increases) as the intake flow speed increases, and when the engine reaches maximum control speed, the differential pressure between the dynamic pressure and the static pressure causes the biasing force of the coil spring. becomes larger, the governor valve moves in the closing direction, and the intake flow that collides with the governor valve surface further causes a force.
<A moment is applied in the direction of closing the nahalb, and the hannahalb becomes fully closed, controlling the maximum rotation of the engine.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a main part of an air gun 20 according to an embodiment of the present invention, and FIG. 2 shows a cam 9 disposed on the air gun 20.
and a layout diagram of the coil spring 11. Portions common to those in FIGS. 6 and 7 of the prior art described above are designated by the same reference numerals, and detailed description thereof will be omitted.

1 is the carburetor, 2 is the carburetor throttle valve,
The air governor 20 is composed of a cylinder 5, an air governor throttle valve 6, a piston door, and a stabilizer piston 8, to which a cam 9, a leaf spring 10, and a coil spring 11 are arranged via an air governor valve shaft 21. . The feature of this air governor 20 is that it does not have an airport 19 (Fig. 6) as in the conventional example.
Instead, a dynamic pressure intake port 3 is provided inside the intake passage F, with its inlet facing the direction of the intake air flow, and the dynamic pressure PD of the intake air is used as a stabilizer. This is because atmospheric pressure P0 is introduced into the right chamber 23 of the piston 8 instead of the conventional atmospheric pressure P0. Further, the static pressure suction boat 4 is similar to the conventional air port 18 shown in FIG. In FIG. 1, solid lines indicate that both the carburetor throttle valve 2 and the air governor throttle valve 6 are in a fully open state, and broken lines indicate the positions of the respective valves in a fully open state.

The operation of the air governor 20 with the above configuration will be explained next. First, when the engine is stopped, the state is similar to that shown in FIG. 8(a), and the carburetor throttle valve 20
is fully closed and in the position shown in FIG. 120, and the air governor valve 6 is fully opened by the tension of the coil spring 11 and is in the position shown in FIG. 16. Next, when the engine is started and the engine is idling, the flow velocity of the intake air flowing in the intake passage 17 is still small, so the dynamic pressure PD acting on the dynamic pressure suction boat 3 and the static pressure P acting on the static pressure suction boat 4. (Therefore, the biasing force of the coil spring 11 is much larger than the differential pressure (PD
remains fully open and does not move. Next, when the engine speed increases to medium speed, the dynamic pressure P9 increases accordingly, but the governor valve 6 is not moved yet, and the governor valve 6 remains fully open. As the engine speed further increases and becomes a high-speed rotation, and as it approaches a predetermined maximum rotation range, the dynamic pressure P increases as the intake flow velocity increases, and when the engine reaches the maximum control rotation, the right chamber of the stabilizer piston 8 23 and the left chamber 22 of the stabilizer piston 8.
The difference (PD PS) from the static pressure Ps inside the coil spring 1
The biasing force of the stabilizer piston 8 becomes larger than the biasing force of the stabilizer piston 8.
moves to the left in the drawing, and the air governor valve 6 tilts in the closing direction. At this time, the flow of intake air directly collides with the surface of the governor valve 6, causing a dynamic pressure P.

As a result, the governor valve 6, which is eccentrically attached to the air governor valve shaft 21, receives a rotational moment as shown by the arrow in the drawing, and as this rotational force is applied, the governor valve is increasingly accelerated in the closing direction, and becomes a fully closed state. , controls the maximum rotation of the engine.

Figure 3 shows the pressure difference between the dynamic pressure P and the static pressure P (PD-P
A diagram of the relationship between S) and engine speed is shown. As shown in the figure, as the engine speed increases, the rate of increase in this pressure difference increases rapidly, and at some point exceeds the biasing force of the coil spring as described above.

FIG. 4 shows an engine rotational speed-governor valve opening diagram from engine startup to NMR when the carburetor throttle valve 2 is fully opened, according to this embodiment. This figure corresponds to the conventional example shown in Fig. 5, in which the governor valve 6 does not close until the engine speed reaches from ■ to ◎, and only at the maximum control speed ◎ does the governor valve 6 operate and begin to close. Fully closed at [F] of maximum no-load rotation NMR.

Due to the above-mentioned configuration, according to this embodiment, the governor valve is always fully open and never closes until the engine reaches the set maximum rotational speed. The engine starts easily without being blocked at low to medium speeds, and
Improves engine acceleration and response.

Note that the means for extracting dynamic pressure and static pressure in the present invention are as follows:
The present invention is not limited to the above embodiments, but includes various embodiments within the scope of the claims.

〔Effect of the invention〕

By implementing the present invention, the air governor throttle valve opens and closes only during no-load maximum rotation (N?IR) control, and the air governor valve is always fully open at startup and at low and medium speeds. This eliminates the conventional resistance to intake air flow due to the governor valve being activated during startup and low-to-medium speed operation, improving engine startability and improving acceleration and response.

[Brief explanation of drawings]

1 to 4 show drawings related to the present invention, FIG. 1 is a sectional view of essential parts of an air governor device according to one embodiment, FIG. 2 is a schematic diagram of the arrangement of a coil spring with the air governor, and FIG.
FIG. 4 shows an engine speed--dynamic pressure and static pressure difference diagram, and FIG. 4 shows an engine speed--governor valve opening diagram. 5th to 8th
The figures show drawings related to the prior art, in which Fig. 5 is an engine speed-governer valve opening diagram, Fig. 6 is a sectional view of essential parts of the air governor, Fig. 7 is a schematic diagram of the arrangement of the coil spring with the air governor, and Fig. Figure 8 (a) to (d) are diagrams explaining the operation of the air governor. (a) is when the engine is stopped, (b) is when the engine is idling, (C) is when the engine is at medium speed, and (d) is when the engine is at high speed. shows. 2... Café reta throttle valve, 5... Cylinder, 6... Air governor throttle valve, 7... Piston rond, 8... Stabilizer piston, 11... Coil spring, 17... Intake aisle. Fig. 1 1... Carburetor 2... Carburetor throttle valve 3... Dynamic pressure suction port 4... Static pressure suction boat 5... Cylinder 6... Air governor throttle valve 7... Piston rond 8... Stabilizer piston 17... Intake passage 20... Air governor 21... Air governor valve shaft Fig. 2 9... Cam 10... Leaf spring 11... Coil spring low/medium Engine speed → Figure Figure 7 Figure 18...Vacuum boat 19...Air port 22...Left chamber of piston 23...Right chamber of piston

Claims (1)

[Claims] 1. An air governor throttle valve is disposed on the downstream side of the carburetor throttle valve, the air governor throttle valve is equipped with a coil spring that always biases the valve to the open position, and the air governor throttle valve is provided with a coil spring that always biases the valve to the open position, and the intake passage on the downstream side of the carburetor throttle valve In an air governor device for a gasoline engine, the opening of the air governor throttle valve is adjusted by rotating the air governor throttle valve using a piston rod connected to a stabilizer piston that senses internal pressure and operates, wherein the stabilizer piston is fitted and slid. In the cylinder, dynamic pressure and static pressure of the intake flow in the intake passage are respectively taken into two cylinder chambers partitioned by the stabilizer piston, and the stabilizer piston senses the differential pressure between the two pressures. An air governor device for a gasoline engine, characterized in that the air governor device is configured to operate with