JP2524903Y2 - Air governor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an air governor that restricts the amount of air-fuel mixture to be introduced into an engine disposed in an intake passage between a carburettor and an engine, and suppresses engine overspeed.

(Prior art)

Japanese Laid-Open Utility Model Publication No. 62-197739 discloses an air governor of this type, which resiliently biases a governor valve, which is rotatably provided in an intake passage and adjusts a flow passage area of the passage, in an opening direction and applies a force to a cylinder. An air governor is disclosed which is connected to a slidably fitted stabilizer piston via a rod, connects a rod side chamber of the cylinder to the intake passage, and connects a head side chamber to the atmosphere.

According to the air governor having such a configuration, when the engine speed at full load increases and the negative pressure generated in the intake passage increases, the stabilizer piston slides in the direction to close the governor valve, and the negative pressure introduced into the rod side chamber of the cylinder. The rotation of the governor valve is stopped when the pressure difference between the pressure and the atmospheric pressure of the head side chamber is balanced with the resilience for biasing the governor valve.
That is, even when the throttle valve of the carburettor is fully opened, the intake passage is restricted by the governor valve, so that the amount of intake air-fuel mixture is limited, and the engine can be prevented from over-rotating.

By the way, in an engine equipped with an air governor, an ignition timing control device is provided which detects a negative pressure between a throttle valve and a governor valve of a carburettor and a negative pressure near a lower end of the governor valve and performs an advance control according to an engine load. There is something.

An example of this type of ignition timing control device is shown in FIG. The device includes a vacuum advancing device 2 connected to a breaker plate of a distributor 1 and a vacuum control valve 3 for switching and controlling a negative pressure introduced to the advancing device 2. The vacuum control valve 3 has a pair of upper and lower spool lands 3a and 3b.
Are slidably fitted in a valve chamber 5 formed in the body of the first embodiment, and are urged upward by a spring 6 in the figure.

In addition, the throttle valve 8
Is formed in the intake passage 9 near the upper end of the port Pa. On the other hand, the body of the air governor 4 has a port Pb opening to the intake passage 9 between the throttle valve 8 and the governor valve 10 and a port Pc opening to the intake passage 9 near the lower end of the governor valve 10. The port Pa is connected to the valve chamber 5 between the spool lands 3a and 3b via a through hole 5a which is electrically connected or blocked by the spool land 3a, and the port Pb is a valve chamber above the spool land 3a via the through hole 5b. 5 is connected. The port Pc is connected to the valve chamber 5 below the spool land 3b, and is connected to the valve chamber 5 between the spool lands 3a and 3b via a through hole 5c which is connected or disconnected by the spool land 3b. . And both spool land
The valve chamber 5 between 3a and 3b is connected to the vacuum advancing device 2 through a through hole 5d.

According to the ignition timing control device having such a configuration, the governor valve 10 is almost fully closed during the idling operation in which the throttle valve 8 is almost fully closed (the state shown in FIG. 2). At this time, the port Pa is almost at atmospheric pressure, and the pressure difference between the port Pb and the port Pc is small. Therefore, the vacuum control valve 3 is urged by the spring 6 to move upward, and the through-hole 5a is conducted, so that the port Pa passes through the through-hole 5a, the valve chamber 5, and the through-hole 5d to the vacuum advancing device 2. Atmospheric pressure will be introduced. Therefore, no vacuum advance is performed at this time.

When the throttle pedal 8 is slightly opened by depressing the access pedal from idling operation, the engine speed rises and a negative pressure is generated near the port Pa, and this negative pressure is introduced into the vacuum advancing device 2, so that the vacuum advancing advances. I do. At this time, since the governor valve 10 rotates in the opening direction, a pressure difference occurs between the port Pb and the port Pc, and the vacuum control valve 3 moves downward against the spring 6.
Further depress the accelerator pedal to release the throttle valve 8
Is substantially half-opened, the governor valve 10 is almost half-opened. At this time, the pressure difference between the port Pa and the port Pb increases, and the vacuum control valve 3 moves further downward to block the through hole 5a and to conduct the through hole 5c. Therefore, the valve chamber 5 between the port Pc and the two spool lands 3a and 3b,
Since a large negative pressure is introduced into the vacuum advancing device 2 through the through-hole 5d, the vacuum advancing speed advances rapidly and then stabilizes.

[Problems to be solved by the invention]

By the way, when an air governor such as that disclosed in Japanese Utility Model Laid-Open No. 62-197739 is used as the air governor 4 in the ignition timing control device, a large negative pressure generated in the intake passage 9 downstream of the governor valve 10 when the engine is rapidly decelerated. Since the stabilizer piston moves abruptly and the governor valve 10 is closed too much, the intake passage 9 is closed, so that the negative pressure downstream of the governor valve further increases. Therefore, the pressure difference between the port Pc and the port Pb increases, and the upward bias of the control valve 3 by the spring 6 is reduced. As a result, the response of the switching operation of the vacuum control valve 3 is delayed and the vacuum advance is maintained, so that the deceleration time until the idling operation is prolonged, and the fuel consumption is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an air governor that can prevent the governor valve from closing too close during sudden deceleration.

[Means for solving the problem]

In order to achieve the above object, the present invention resiliently biases a cabana valve that is rotatably provided in an intake passage and adjusts a flow passage area of the passage in an opening direction and slidably fits in a cylinder. The union nipple is formed at the open end of the head side chamber of the cylinder in an air governor which is connected to the stabilizer piston through a rod, connects the rod side chamber of the cylinder to the intake passage, and connects the head side chamber to the atmosphere. A scavenging passage which penetrates the nipple portion is formed in the plug, and a first throttle portion is provided in the scavenging passage at a base end thereof, that is, at a position close to the head side chamber, and a scavenging passage is formed in the nipple portion. Two throttle portions are provided, and two throttle portions are integrally formed at both ends of one plug.

[Action and effect of the invention]

According to the above configuration, a scavenging passage having two throttle portions is easily formed simply by fitting a plug into the opening end of the cylinder, and the first throttle portion is provided in the scavenging passage near the head side chamber. With this arrangement, the passage space between the head-side chamber and the first throttle portion is reduced, and the air in the head-side chamber can be further increased in negative pressure, that is, the air cushion effect is further enhanced, and the sudden movement of the stabilizer piston is effectively suppressed. it can. Further, the degree of suppression can be adjusted by the second throttle portion, so that a piston moving speed suitable for engine performance can be obtained.

In addition, since the first and second apertures are provided, the diameter of the aperture at each stage can be relatively large as compared with the one-stage aperture. Therefore, foreign matter such as dust in the air flowing into the head side chamber is less likely to be clogged in the throttle portion, and the performance is stabilized.

〔Example〕

The present invention will be described below with reference to the drawings. FIG. 1 shows an air governor according to an embodiment of the present invention. An intake passage 12 and a cylinder 13 are formed in the body of the air governor 11, and a governor valve 14 that variably adjusts a passage area of the passage 12 is provided in the intake passage 12 with respect to the intake passage 12.
It is provided to be rotatable about a pivot 15 eccentric to the 16 side. The governor valve 14 is elastically urged in the opening direction (the direction of arrow A) by a spring (not shown).

On the other hand, a stabilizer piston 16 is slidably fitted to the cylinder 13, and the piston 16 and the governor valve 14 are connected via a rod 17. This rod 17 has a conductive groove
The intake passage 12 and the cylinder are formed through the groove 17a.
The thirteen rod-side chambers 13a communicate with each other. Also, Shinrida 1
A scavenging passage 18a is formed in the plug 18 fitted to the opening end face of the opening 3, and the head side chamber 13b of the cylinder 13 is communicated with the atmosphere via the passage 18a. A first throttle 18b and a second throttle 18c are provided at both ends of the scavenging passage 18a, respectively.

In the present embodiment having the above-described configuration, a large negative pressure is generated in the intake passage 12 downstream of the governor valve 14 during a partial load operation in which the throttle valve of the carburettor includes idle, so that the differential pressure between the rod side chamber 13a and the head side chamber 13b is also large. Therefore, the governor valve 14 has a governor valve 14 opening degree corresponding to the throttle valve opening degree by a force due to its own eccentric moment and a spring force urging in a fully open direction (not shown).

When the throttle valve is opened and fully opened, the engine speed increases and a negative pressure is generated in the intake passage 12, and the negative pressure is introduced into the rod side chamber 13a through the conduction groove 17a, so that the rod side chamber 13a and the head side chamber 13b differential pressure increases. As a result, the stabilizer piston 16 slides in the direction to close the governor valve 14, and the governor valve 14 becomes almost half-open as shown by a dashed line in FIG. As a result, the intake passage 12 is throttled, so that the amount of intake air-fuel mixture is restricted, and the engine can be prevented from overrunning.

However, in the conventional air governor, when the engine is suddenly decelerated, the stabilizer piston 16 moves rapidly due to a large negative pressure generated in the intake passage 12, and the governor valve 14 closes too far to the fully closed position as shown by the broken line in FIG. However, according to the air governor 11 according to the present embodiment, the first
And the second throttle portion, the first throttle portion 18b is provided near the head side chamber 13b, and the second throttle portion 18c is provided at the outlet of the scavenging passage spaced apart from the first throttle portion. At the time of deceleration, the head-side chamber 13b functions as an air spring to suppress a sudden increase in the differential pressure between the head-side chamber 13a and the chamber 13a, thereby preventing the governor valve 14 from being over-closed. Therefore, if the air governor 11 according to the present embodiment is applied to the ignition timing control device shown in FIG. 2, it is possible to prevent a response delay in the switching operation of the vacuum control valve at the time of sudden deceleration. And the fuel economy can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of an air governor according to an embodiment of the present invention,
FIG. 2 is a configuration diagram schematically showing a conventional ignition timing control device provided with an air governor. 11 ... air governor, 12 ... intake passage, 13 ... cylinder,
13a …… Rod side chamber, 13b …… Head side chamber, 14 …… Governor valve, 16 …… Stabilizer piston, 17 …… Rod,
18a: Scavenging passage, 18b, 18c ... Restrictor

Claims (1)

(57) [Scope of request for utility model registration] 1. A stabilizer piston rotatably provided in an intake passage and resiliently biasing a governor valve for adjusting a flow area of the passage in an opening direction and slidably fitted to a cylinder. A plug having a union nipple protruded from an open end of the head side chamber of the cylinder is connected to an air governor which is connected via a rod and connects the rod side chamber of the cylinder to the intake passage and the head side chamber to the atmosphere. A scavenging passage that penetrates the nipple portion is formed in the plug, and a first throttle portion is provided in the scavenging passage at a base end thereof, that is, at a position close to the head side chamber, and a second throttle portion is provided in the nipple portion. Provided, 1
An air governor wherein two throttle portions are integrally formed at both ends of each plug.