JPS6220673Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a knocking prevention device for a gasoline engine. It is an object of the present invention to provide the same device in which knocking can be prevented by reducing the ratio.

[Prior Art] Knocking often occurs when a gasoline engine is rapidly switched from low speed to high speed, such as when starting or climbing a hill, and this not only causes an extremely unpleasant feeling, but also affects the durability of the gasoline engine. From this point of view, it is extremely harmful.

As a means to prevent this knocking, methods such as delaying the ignition timing or increasing the valve overlap are widely used, but both of these methods worsen fuel efficiency.
Not the preferred method.

[Problems to be solved by the invention] The present invention was made in view of this point, and it is based on the fact that knocking can be reduced by lowering the compression ratio of a gasoline engine, and that knocking is reduced by lowering the compression ratio of a gasoline engine. Focusing on the fact that knocking tends to occur when rapidly switching to high-speed rotation, but is less likely to occur at high-speed rotation, we have developed a system that temporarily reduces the actual compression ratio when rapidly switching from low-speed rotation to high-speed rotation in a gasoline engine. The purpose is to prevent knocking.

[Means for Solving the Problems] The configuration of the present invention includes an actuator that operates an on-off valve disposed above a carburetor equipped with a throttle valve in an intake system of a gasoline engine using a ventilator negative pressure, and a ventilator of the carburetor. The knocking prevention device is provided with a delay valve that delays the opening operation of the opening/closing valve when the throttle valve is rapidly opened in a pipe connecting the throttle valve and the throttle valve.

[Operation] When the throttle valve T is rapidly opened and the rotation speed is rapidly changed from low speed to high speed, the delay valve D provided in the pipe 10 causes a temporary delay in transmitting the ventilary negative pressure to the actuator 6. As a result, the opening operation of the on-off valve 1 is also temporarily delayed, so that the amount of intake air is reduced, the actual compression ratio of the gasoline engine is reduced, and knocking is prevented.

[Embodiment of the invention] An embodiment of the invention shown in the drawings will be described in detail below. Reference numeral 1 designates an on-off valve rotatably provided by a shaft 2 in a case 3 mounted above a carburetor 11 equipped with a throttle valve T of an intake pipe 5 in an intake system K of a gasoline engine E; An arm 4 for rotating the shaft 2 is provided at one end of the shaft 2. Further, 6 is a pressure-responsive actuator, which includes a negative pressure chamber 8 and an atmospheric chamber 9 with a diaphragm 7 in between.
The negative pressure chamber 8 is connected to the ventilate section 12 of the carburetor 11 of the intake pipe 5 through a suitable pipe 10 and a delay valve D, so that a ventilary negative pressure V acts thereon. .
On the other hand, the atmospheric chamber 9 communicates with the atmosphere through a hole 13, and a spring 13 for pressing the diaphragm 7 is disposed within the negative pressure chamber 8. Further, a rod 14 extending outward through the negative pressure chamber 8 is integrally attached to the diaphragm 7, and the outer end of the rod 14 is connected to the shaft 2 of the on-off valve 1 via a suitable link 15. It is connected to an integral arm 4.

Further, the rod 14, link 15, etc. are adjusted so that even when the on-off valve 1 is in the fully closed state shown by the solid line in the figure, a small flow path can be secured between it and the case 3.

In the device of the present invention having the above structure, knocking is prevented in the following manner.

When the gasoline engine E rotates at a low speed, the opening degree of the throttle valve T is small and the amount of intake air is small, so the ventilary negative pressure V is extremely weak. Therefore, the diaphragm 7 of the actuator 6 is pressed to the left in the figure by the spring 13, and the rod 14 integrated with this diaphragm pulls the link 15 to rotate the arm 4 and move the on-off valve 1 to the left in the figure. It is held in the closed position shown by the solid line.

If the throttle valve T is suddenly opened in such a state, that is, when the rotation is rapidly changed from low speed to high speed, a strong negative ventilary pressure V will be applied to the ventilary part 12 of the carburetor 11 as the amount of intake air increases. Occur. This negative pressure V is transmitted to the negative pressure chamber 8 of the actuator 6 via the pipe 10 and the delay valve D, bends the diaphragm 7 against the spring 13, and rotates the arm 4 via the rod 14 and link 15. The on-off valve 1 is held in the open position shown by the two-dot chain line in the figure.

In this case, in this embodiment, the delay valve D
is arranged in the pipe 10, there is a temporary delay between the generation of the ventilary negative pressure V and the operation of the actuator 6, and accordingly, the on-off valve 1
Since the opening operation of the valve is also temporarily delayed, the intake air is appropriately throttled during the delay time.

Therefore, during this period, the amount of intake air is temporarily reduced by the action of the on-off valve 1 and the delay valve D as described above, and the actual compression ratio of the gasoline engine E is reduced, causing the engine to change from the low-speed rotation as described above. This prevents knocking, which tends to occur under conditions such as when rapidly switching to high speed rotation.

Of course, when the gasoline engine E is in a high-speed rotation state, knocking itself is unlikely to occur, so the on-off valve 1 is naturally in a fully open state, so in this case there is no need to throttle the intake air and cause a reduction in output. do not have.

[Effects of the invention] As described above, the knocking prevention device of the present invention has the following effects:
When the throttle valve is rapidly opened, there is a pipe connecting an actuator that operates an on-off valve disposed above a carburetor equipped with a throttle valve in a gasoline engine intake system with a ventilator negative pressure and the ventilate part of the carburetor. Since a delay valve is provided to delay the opening operation of the opening/closing valve, knocking does not occur, as occurs when the throttle valve is rapidly opened to rapidly switch the rotation of a gasoline engine from low speed to high speed. Under easy circumstances, the opening operation of the on-off valve is delayed by the delay valve, and by temporarily throttling the intake air, the actual compression ratio can be reduced and knocking can be reliably prevented.

In addition, by preventing knocking, unnecessary shocks and vibrations can be avoided to the engine, so that the durability of the engine is improved and the unpleasant feeling during operation is eliminated.

Furthermore, since the device of the present invention simply temporarily throttles the intake air and lowers the actual compression ratio, it does not change the combustion process of the engine, unlike conventional methods of delaying ignition timing or increasing valve overlap. Since the engine does not give rise to a large amount of fuel, the fuel consumption rate of the engine can be improved.

Moreover, since knocking can be prevented with an extremely simple device, it is advantageous in that it is inexpensive, economical, and of great practical value.

[Brief explanation of the drawing]

FIG. 1 is a partially enlarged longitudinal cross-sectional schematic diagram showing an embodiment of the present invention. 1: Open/close valve, 2: Shaft, 3: Case, 4: Arm, 5: Intake valve, 6: Actuator, 7: Diaphragm, 11: Carburetor, 12: Ventilation part, 14: Rod, 15: Link, D: Delay valve, E: Gasoline engine.

Claims (1)

[Scope of utility model registration request] Rapid opening of the throttle valve is located in a pipe connecting the ventilate section of the carburetor and an actuator that operates the opening/closing valve disposed above the carburetor equipped with a throttle valve in the intake system of a gasoline engine by means of negative ventilary pressure. The knocking prevention device is provided with a delay valve that sometimes delays the opening operation of the on-off valve.