JPS5857038A - Control mechanism of dashpot - Google Patents

Abstract

PURPOSE:To realize improvement of drivability of an engine while preventing its emission from worsening, by limiting the opening of a throttle valve through a dashpot and changing a condition of the dashpot operative or inoperative in accordance with a condition of the engine. CONSTITUTION:In case of low temperature of cooling water when a water temperature switch 40 is turned on, an electric current is conducted to flow in a coil 39, and a shifting valve 37 is moved leftward against a spring 38 to close a selector passage 34. In consequence, when a throttle valve 7 is closed, a chamber 14 in a dashpot 9 is communicated to the outside air through an orifice 49 in a delay valve 46, and a piston 15 is gradually lowered to prevent a rapid close of the throttle valve 7. While in case of high cooling water temperature, if the water temperature switch 40 is turned off, the shifting valve 37 both opens the selector passage 34 and closes a selector passage 35. In consequence, negative pressure in an intake passage 43 is introduced into the chamber 14, and the piston 15 is lowered through a diaphragm 12 to a position the piston is not contacted to a cam body 8, then the dashpot 9 is changed to an inoperative condition.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dashpot that regulates the opening of a throttle valve, and in particular, to improve the drivability of a vehicle by controlling the dashpot so that it does not operate in unavoidable cases. Regarding the control mechanism of the dashpot that can be used.

First, the configuration of a conventional dashpot will be explained with reference to FIG. Carburetor 1 (In this example, it is a two-barrel type)
A primary intake passage 2 and a secondary intake passage 3 are formed inside the intake passage 2, and venturi portions 4 and 5 are provided in both intake passages 2 and 3, respectively.

A shaft 6 that is linked to the accelerator pedal is pivotally supported at the lower part of the primary suction passage 2. A throttle valve l is fixed in the primary suction passage 2 of the shut 6, and the carburetor 1 of the shaft 6 A fan-shaped cam body 8 is fixed to the outside of the cam body. A dashpot 9 is located at the lower side of the carburetor 1, and the outer shell of the dashpot 9 is formed by a hemispherical upper cover 10 and a lower cover 11. Both ends are engaged and kept airtight from the outside. A rubber diaphragm 12 is installed between the upper cover 10 and the lower cover 11.
is positioned and the diaphragm 12 closes the cover 1.
0.11 is divided into a pressure chamber 13 and a diaphragm chamber 14. A piston 15 that contacts the cam body 8 is inserted into the upper part of the upper cover 10, and the lower end of the piston 15 is inserted into the center of the diaphragm 12.
Actuators 16 and 17 are in contact with the center of the upper and lower surfaces of 2, respectively, and a nut 1 screwed in from the lower end of the piston 15
8 fixes the diaphragm 12 and actuator 16,17. A spring 19 is interposed between the lower cover 11 and the actuator 11, and the spring 19 urges the piston 15 upward. FIG. 2 is an enlarged view of the center of the diaphragm 12. The outer circumference of the lower actuator [117] is raised, and the diaphragm 12 sandwiched between the two actuators 16 and 17 is vertically moved. It is given the freedom to vibrate. The actuator 11
A plurality of ports 20 and 21 are opened at corresponding positions on the diaphragm 12, and a port 22 is opened on the upper actuator 16 at a position that does not overlap with the port 21. A groove-shaped orifice 23 is formed, and a passage 24 communicating with the A-recess 23 is formed at a position near the piston 15 at the center of the diaphragm 12.

To explain the operation of this conventional dashpot 9,
Si1? When the foot 6 is rotated by the accelerator pedal, the throttle valve 7 and the cam body 8 are rotated, the piston 15 and the cam body 8 do not contact each other, and the piston 15 is urged upward by the spring 19 to a predetermined position. It stands out. When the accelerator pedal is released, shaft 6 and throttle valve 7
, the cam body 8 rotates in the opposite direction, and the piston 1 is attached to the cam body 8.
5 comes into contact with each other, and the throttle valve 7 is gradually returned to its original position, thereby preventing its sudden closing. When the piston 15 is pressed down by the cam body 8, the die hair flamm 1.2 is in the state shown in FIG.
It flows in the order of orifice 23 and through 1] 22, and is provided with resistance. Therefore, the piston 15 moves slowly due to the resistance caused by the air flow in addition to the spring 19, and the cam body 8,
Since the rotation of the throttle valve 1 is also regulated by the operation of the piston 15, afterburn is prevented. Then, when the accelerator pedal is depressed again, the contact between the cam body 8 and the piston 15 is released, and the piston 15 is moved upward by the spring 19. At this time, the diaphragm 12 is in the position shown in FIG. The spring 19 causes it to move rapidly and wait for the next operation.

As described above, the movement of the throttle valve 7 is regulated by the dashpot 9, preventing it from closing suddenly, and the occurrence of afterburn can be prevented. However, since this dashpot 9 operates all the time regardless of the temperature of the engine cooling water, etc., some shelves impair self-help type drivability. For this reason, a mechanism has been proposed that operates the dashpot 9 only when necessary to improve drivability.

For example, Japanese Patent Publication No. 54-11858 is given as a specific example. In this proposed configuration, the dashpot is controlled by I according to the vehicle speed, and when the vehicle speed is ^ speed, the dashpot is held at a predetermined opening degree. Regardless of whether the throttle valve y@maro is large or small, it is possible to prevent the deterioration of the engine. However, even with this configuration, the dashpot was in constant operation, impairing drivability.

In view of the above-mentioned drawbacks, the present invention provides a dashpot control III structure that does not operate the dashpot when unnecessary to improve drivability, and operates the dashpot when necessary to prevent deterioration of emissions. There is something to offer.

In other words, in the present invention, unnecessary and necessary points are set at high and low engine cooling water temperatures, and when the water temperature is low, the intake air-fuel mixture is rich due to the action of the choke, etc., and the ignition timing is also low. Even if the temperature of the exhaust system is not extremely high, the engine is likely to misfire.
Unburnt gas passes through the engine and burns out in the exhaust system.
So-called afterburn is likely to occur.

Therefore, in order to prevent afterburn at low temperatures and to prevent the discharge of unburned gas, the dash: 1 pot is operated at low temperatures to solve the problems that occur during deceleration.

An embodiment of the present invention will be described below with reference to FIG.

In this embodiment, the same members as those in the conventional configuration shown in FIG. 1 are denoted by the same reference numerals, and their explanations are omitted. In the embodiment of FIG. 3, neither the diaphragm 12 nor the actuator 16.
3 and the diaphragm chamber 14 are configured not to communicate with each other, and a communication pipe 30 is installed at the lower part of the diaphragm chamber 14. Reference numeral 31 denotes an electrically operated three-way switching valve, and the main body 32 of the three-way switching valve 31 has an elongated operating space 33.
is formed, and a switching path 3 is formed at both ends of this working space 33.
4 and 35 are open, and an operating path 36 is open at the side of the operating space 33. A metal moving valve 37 is enclosed within this working space 33, and this moving valve 31
is constantly urged in the direction of the switching path 35 by a spring 38.

A coil 39 is wound around the outer periphery of the main body 32, and this coil 39 has an F.
An IA degree switch 40 and a battery 41 are connected in series. The communication pipe 30 and the operating path 36 are connected by a pipe 42, and the switching path 34 is connected to a manifold pipe 43.
It is connected by a communicating path 44 and a pipe 45 formed in the. Further, 46 is a delay valve, and inside this delay valve 46 is a cavity 4.
7 is formed, and the cavity 47 and the switching path 35 are connected to the pipe 4.
8 is continuous. A partition wall 52 is formed in the cavity 41, and a filter 51 is further formed in the cavity 47.
is connected.

Next, the operation of this embodiment will be explained.

When the cooling water temperature is low.

The water temperature switch 40 is on, a current flows through the =1 ile 39, and the movable valve 37 moves to the left against the spring 38, closing the switching path 34. Therefore, the diaphragm chamber 14 includes the pipe 42, the operating path 36, and the switching path 35.
, communicates with the cavity 47 via the via 148.

External air flows through the orifice 49 or the one-way valve 50, and when the piston 15 descends, the air flows through the orifice 4.
Since the one-way valve 50 is closed, the piston 15 gradually descends due to the restriction resistance of the orifice. When the piston 15 is pushed up by the spring 19, the volume of the orifice 49 and the diaphragm chamber 14 increases, and the one-way valve 50 also opens, so air flows into the diaphragm chamber 14 with little resistance, and the piston 15 rises rapidly. In this way, the dashpot 9 controls the movement of the piston 15 to prevent the throttle valve 7 from closing suddenly.
This prevents deterioration of emissions and afternoon that occurs when the engine is in low humidity.

When the cooling water temperature is high.

The water temperature switch 40 is turned off, the current flowing through the coil 39 is cut off, and the moving valve 37 is pushed rightward by the spring 38 to close the switching path 35. Therefore, the diaphragm chamber 14 communicates with the manifold vibe 43 via the pipe 42, the working path 36, the working space 33, the switching path 34, the pipe 45, and the communication path 44. The pressure is transmitted, and the diaphragm 12 descends against the biasing force of the spring 19, and the piston 15 also descends to a position where it does not come into contact with the cam rest 8. Therefore, even if the throttle valve 7 is opened or closed by the shaft 6, the movement of the throttle valve 7 is limited to the piston 15.
The throttle valve 7 opens and closes in response to the accelerator pedal, and can be quickly closed from a fully open state, making engine braking effective.

Although the present invention uses a three-way switching valve to control the dashpot using a water temperature switch as described above, it is not limited to this configuration, and a thermo valve may be used, or a vacuum delay valve or the like may be built into the three-way switching valve. It can also be integrated.

Since the present invention is configured as described above, it is possible to operate the dashpot when necessary to prevent sudden closing of the throttle valve, thereby preventing deterioration of the engine engine and 7-fever burn, and preventing the sudden closing of the throttle valve when necessary. can disable the dashpot and control the throttle valve to close quickly, allowing the engine brake to be more effective during deceleration.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the configuration of a conventional dashpot, and FIG. 2 is an enlarged view showing the vicinity of the diaphragm. FIG. 3 is a sectional view showing one embodiment of the present invention. 7... Throttle valve, 9... Dashpot,
12...Diaphragm, 14...Diaphragm chamber,
15... Piston, 31... Three-way switching valve, 43...
・Manifold pipe, 46...delay valve. Patent Applicant Fuji Heavy Industries Co., Ltd. Representative Patent Attorney Jundo Kobashi Patent Attorney Susumu Murai Figure 1

Claims (1)

[Claims] The diaphragm forms a diaphragm chamber in which the internal space is connected to the outside. A piston is connected to this diaphragm, and the movement of the piston is controlled by the air resistance flowing into the diaphragm chamber. This piston causes the rapid closing of the throttle valve. In the dashpot that prevents
A common opening of the three-way switching means is passed through the diaphragm chamber, one switching opening of the three-way switching means is connected to a vacuum delay means, the other switching opening is connected to a manifold pipe, and the three-way switching means is connected to the cooling water temperature. is below a predetermined value, transmits the atmosphere to the diaphragm chamber to prevent sudden closing of the throttle valve, and when the cooling water temperature is above a predetermined value, switches to transmit suction negative pressure to the diaphragm chamber,
A dashpot control mechanism that can suddenly release the throttle valve from locking.