JPH08158943A - Choke valve control device of engine - Google Patents

Abstract

PURPOSE: To prevent a rich engine stop by automatically holding a choke valve at a lean opening after the cold start of the engine. CONSTITUTION: This choke valve control device has an interlocking member 5 that engages with the choke valve 3 of an engine, a diaphragm 6a connected to the interlocking member, and a diaphragm chamber 6A partitioned by the diaphragm. Also, the choke valve control device includes a pressure reacting device 6 which, when negative pressure works on the diaphragm chamber, permits the interlocking member to displace the choke valve in an opening direction; communicating passages 18, 19 each having one end communicated with an intake passage 1 downstream of a throttle valve 2 and the other end communicated with the diaphragm chamber; a check valve 15 provided in the communicating passages to stop the circulation of gases from one end to the other; and a flow regulation means 11b provided in the communicating passages to regulate the flow of gases.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine choke valve control device.

[0002]

2. Description of the Related Art In a vehicle equipped with a carburetor in a fuel supply system for an engine, at the time of cold start, a choke valve provided in an intake passage is closed to obtain a high-concentration air-fuel mixture to improve ignition performance while warming up. When restarting later, open the choke valve from the idle opening to the set opening on the open side to increase the intake air amount,
A choke valve control device equipped with an automatic thinning mechanism for improving the ignition performance by leaning the air-fuel ratio (leanizing) of the air-fuel mixture is installed.

As shown in FIG. 1, a choke valve control device having an automatic thinning mechanism engages a choke lever 4 for opening and closing a choke valve 3 provided upstream of a throttle valve 2 in an intake passage 1 of an engine. Lever 5, choke breaker 6 that drives this lever 5, and this choke breaker 6
It is constituted by a delay (orifice) 8 which is interposed in a communication passage 7 between the diaphragm chamber 6A and the intake passage 1 of the engine and which adjusts the flow rate of gas flowing through the communication passage 7.

The choke valve 3 is fully closed when the engine is cold started, and the fuel sprayed from the nozzle 9 is supplied to the engine in a high-concentration air-fuel mixture (air-fuel ratio is rich). After the engine is started (after the complete explosion), the negative pressure generated in the intake passage 1 gradually acts on the diaphragm chamber 6A of the choke breaker 6 through the communication passage 7 and the delay 8, and the diaphragm 6a resists the spring force of the spring 6b. Then, the lever 5 is gradually displaced to the right in the figure to pull the lever 5, and the choke lever 4 is displaced in this direction to drive the choke valve 3 in the opening direction. As a result, the amount of intake air in the intake passage 1 increases, the mixture is diluted, and the air-fuel ratio becomes lean.

[0005]

When the accelerator pedal is depressed after the engine is started and the vehicle is started, and then the accelerator pedal is released for some reason, the negative pressure in the intake passage 1 decreases, and Along with this, the negative pressure acting on the diaphragm chamber 6A of the choke breaker 6 decreases, the diaphragm 6a is displaced leftward as shown in FIG. 2 by the spring force of the spring 6b, and the choke valve 3 is fully closed. That is, when the temperature is low, the friction of the engine and the mission is large, the low speed side output of the engine is small, and the internal pressure of the intake passage 1 remains reduced even after the accelerator pedal is returned depending on the green state and the variation of the valve clearance. The automatic thinning mechanism does not operate and the choke valve 3 is fully closed. As a result, the air flow rate in the intake passage 1 is reduced, the mixture becomes highly concentrated (rich), and so-called rich engine stall occurs.

Another example of a choke valve control device having an automatic thinning mechanism is a carburetor disclosed in Japanese Utility Model Laid-Open No. 57-20548. This carburetor is transmitted by being delayed by an orifice, a choke valve provided in an intake passage of an engine, a first control means for opening the choke valve to a first opening in response to a negative pressure of an intake pipe, and an orifice. According to the negative pressure of the intake pipe, the choke valve is provided with the second control means for opening the choke valve from the first opening to the second opening larger than the first opening.

However, in this carburetor, when the negative pressure in the intake pipe remains in a reduced state even after the accelerator pedal is returned, as in the case described above, the first control means controls the first opening degree. There is a risk that the engine cannot be held and a rich engine stall will occur. The present invention has been made in view of the above points,
(EN) Provided is an engine choke valve control device for preventing rich engine stall by preventing the choke valve from becoming below the same automatic thinning opening after starting the engine to prevent the mixture from over-concentrating. The purpose is to

[0008]

To achieve the above object, according to the present invention, an interlocking member that engages with a choke valve of an engine, a diaphragm connected to the interlocking member, and a diaphragm chamber partitioned by the diaphragm are provided. A pressure responsive device that displaces the choke valve in the valve opening direction when a negative pressure acts on the diaphragm chamber; one end communicates with an intake passage downstream of the throttle valve; A communication passage communicating with the diaphragm chamber, a check valve provided in the communication passage for blocking the flow of gas from the one end side to the other end side, and a flow rate adjustment provided in the communication passage for adjusting the flow rate of gas. And means.

According to another aspect of the present invention, there is provided an atmosphere opening portion provided in the communication passage on the other end side of the check valve or in the diaphragm chamber, and a valve device opening the atmosphere opening portion when the engine is stopped. It is configured. According to the third aspect, the check valve and the flow rate adjusting means are provided in the same chamber.

According to a fourth aspect of the present invention, the check valve comprises a filter for filtering the fluid. In the present invention, the valve device is an electromagnetic valve.

[0011]

[Function] The negative pressure generated in the intake passage after the engine is started (after the complete explosion) acts on the diaphragm chamber of the pressure responsive means through the check valve and the flow rate adjusting means to displace the interlocking member and automatically open the choke valve. Open to the degree position. When the accelerator pedal is depressed and the vehicle starts, and then the accelerator pedal is released for some reason and the negative pressure in the intake passage decreases, the check valve closes and the negative pressure acting on the diaphragm chamber is reduced. Accumulated and held. As a result, the diaphragm holds the interlocking member at the displacement position, and the choke valve is held at the automatic thinning opening position. As a result, the air-fuel mixture supplied to the engine is prevented from falling into excessive concentration, and rich engine stall is eliminated.

According to the second aspect of the present invention, the valve device provided in the atmosphere opening portion provided in the communication passage between the check valve and the diaphragm chamber is opened when the engine is stopped so that pressure is accumulated in the diaphragm chamber. Release pressure to atmosphere. This ensures the choke effect at the next start.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The same members as those in FIG. 1 are designated by the same reference numerals. In FIG. 3, the choke breaker 6 is divided into a diaphragm chamber 6A and an atmosphere chamber 6B by a diaphragm 6a, and a spring 6b is provided in the diaphragm chamber 6A.
Are compressed to urge the diaphragm 6a toward the atmosphere chamber 6B. The lever 5 has one end engageable with the choke lever 4 and the other end penetrating the center of the atmosphere chamber 6B of the choke breaker 6 and fixed to the diaphragm 6a.

The delay 10 is of a pressure-accumulating type and accumulates the negative pressure generated in the intake passage 1 at the time of starting the engine to keep the choke breaker 6 in an operating state, that is, keep the choke valve 3 open. It is a thing. The pressure-accumulation type delay 10 is configured as shown in FIG. 5, and the container body 11 is divided into two chambers 11A and 11B by a partition wall 11a, and an orifice 11b is formed in the partition wall 11a. ing. The partition 11a has an orifice 11
A hole 11c is formed near b.

The valve body 14 is made of, for example, a rubber member having elasticity, and is formed in an umbrella shape. The shaft portion is inserted into and fixed to the hole 11c of the partition wall 11a from the chamber 11A side to the chamber 11B side. The orifice 11b is closed by the elastic force in close contact with the partition wall 11a. Filters 16 and 17 are housed at the open ends of the chambers 11A and 11B. End plates 12, 1
3 is attached to the open ends of the chambers 11A and 11B, and cooperates with the main body 11 to fix and hold the filters 16 and 17. These end plates 12, 13 have chambers 11A, 11 in the center.
Ports 12a and 13a communicating with B are provided.

The orifice 11b is for applying the negative pressure generated in the intake passage 1 to the diaphragm chamber 6A of the choke breaker 6. The valve body 14 is for holding the negative pressure applied to the diaphragm chamber 6A, and the check valve 15 is constituted by the orifice 11b and the valve body 14. The check valve 15 allows the gas flow only from the chamber 11B to the chamber 11A, that is, the chamber 11A.
To apply a negative pressure only in the direction of the chamber 11B.

Returning to FIG. 3, the port 12a of the delay 10
Is connected through a boost hose 18 to a small hole 1a formed in the intake passage 1 on the downstream side of the throttle valve 2,
The port 13a is connected to the three-way joint 19 via a boost hose.
Is connected to the inlet 19a of the. Exit 19b of the three-way joint 19
Is connected to the inlet of the diaphragm chamber 6A of the choke breaker 6 via the boost hose. An open / close valve, for example, a solenoid valve 20 is connected to the atmosphere opening port 19c of the three-way joint 19. This solenoid valve 20 is a normally-open type on / off solenoid valve which is opened when the solenoid 20a is deenergized so that the atmosphere opening port 19c communicates with the atmosphere opening port 20c, and when energized, the valve body 20b is opened. Closes the air release port 19c. The solenoid valve 20 is closed by energizing the solenoid 20a when the ignition switch is turned on, that is, when the engine is started.

The operation will be described below. In FIG. 3, the choke valve 3 is fully closed when the engine is cold started,
The air-fuel ratio of the air-fuel mixture is rich. At this time, the solenoid valve 20 is energized and closed. The negative pressure generated in the intake passage 1 after the engine is started (after the complete explosion) acts on the chamber 11A of the pressure-accumulation delay 10 through the boost hose 18 and the filter 16, and the valve element 14 resists its elastic force. Then, it is separated from the orifice 11b and opened. That is, the check valve 15 opens. The negative pressure in the chamber 11A acts on the chamber 11B through the orifice 11b, and further acts on the diaphragm chamber 6A of the choke breaker 6 to cause the spring 6
The diaphragm 6a is displaced rightward in the figure against the spring force of b. Along with the displacement of the diaphragm 6a, the lever 5 is pulled as shown by the arrow to move the choke lever 4 to the right in the figure, and the choke valve 3 is automatically thinned to the opening position.

Now, when the accelerator pedal is released for some reason after the vehicle has started and the throttle valve 2 returns to the idle position as shown in FIG. 4, the negative pressure in the intake passage 1 decreases, and with this, Chamber 11A of pressure accumulation type delay 10
The negative pressure of is reduced. On the other hand, the chamber 11B side of the delay 10 is under negative pressure, and the valve body 14 closes the return orifice 11b by its elastic force. That is, the check valve 15 is closed. As a result, the chamber 11B of the delay 10 to the three-way joint 19
~ Negative pressure is accumulated between the diaphragm chambers 6A of the choke breaker 6, the diaphragm 6a is held at that position, and the choke valve 3 is held at the automatic thinning opening position. As a result, the mixture is prevented from falling into excessive concentration, and rich engine stall is prevented. Thus, after the start, the choke valve 3 is always prevented from becoming less than the automatic thinning opening, and the rich engine stall is eliminated.

When the ignition switch is turned off or the engine is stopped due to engine stall or the like, the solenoid 20a of the solenoid valve 20 is deenergized, the valve body 20b is opened, and the atmosphere opening port 19c of the three-way joint 19 is opened to the atmosphere. Be communicated to. As a result, the negative pressure accumulated between the chamber 11B of the delay 10 to the three-way joint 19 to the diaphragm chamber 6A of the choke breaker 6 is released to the atmosphere, and the diaphragm chamber 6a of the choke breaker 6 is opened by the spring force of the spring 6b. Displaces to the left and returns to the original position. As a result, the choke lever 4 is released from the lever 5, and the choke valve 3 is closed to wait for the next start. This prevents the choke valve 3 from opening too much when restarting the engine, and ensures the choke effect.

In the above embodiment, the valve body 14 for opening and closing the orifice 11b is provided in the pressure accumulating delay 10, and the check valve 15 is constituted by the orifice 11b and the valve body 14, but the invention is not limited to this. Instead of the orifice 11b, a check valve may be provided in the communication passage between the diaphragm chamber 6A of the choke breaker 6 and the intake passage 1, for example, in the middle of the boost hose 18.

FIG. 6 shows another example of use of the present invention, in which a thermo valve is further provided so that the choke valve 3 does not act when the engine water temperature is high. In the figure, a choke breaker 21 includes two diaphragm chambers 21A and 21B, a lever 5 engaging the choke valve 3 is connected to a first diaphragm 21a, and a first three-way joint 19 is connected to the first diaphragm chamber 21A. Solenoid valve 2
0 and the chamber 11B of the delay 10 are connected, the chamber 11A of the delay 10 is connected to the intake passage 1 via the boost hose 18, and the second diaphragm chamber 21B is opened / closed according to the boost hose 22 and the engine cooling water temperature. The configuration is such that it is connected to the intake passage 1 via a thermo valve 23.

The thermo-valve 23 is closed when the engine water temperature is low to shut off the second diaphragm chamber 21B of the choke breaker 21 from the intake passage 1 and render the second diaphragm 21b inoperative to bring the choke valve 3 into operation. Close
When the engine water temperature is high, the valve is opened so that the second diaphragm chamber 21B communicates with the intake passage 1, and the second diaphragm 21b is operated to open the choke valve 3 so that the choke valve 3 does not operate.

[0024]

As described above, according to the present invention, the negative pressure acting on the diaphragm chamber is retained when the depression of the accelerator pedal is released after the engine is started and the vehicle is started. By maintaining the choke valve at the automatic thinning opening position, the mixture supplied to the engine is prevented from falling into excessive concentration, and rich engine stall is eliminated.

According to the second aspect of the present invention, when the engine is stopped, the negative pressure stored in the atmosphere opening portion provided between the check valve and the diaphragm chamber is released to the atmosphere, whereby the choke valve returns to the closed position and the next The choke effect at engine start is secured. In the third aspect, by providing the check valve and the flow rate adjusting means in the same chamber, the number of parts of the device can be reduced and the device can be made compact.

According to the present invention, the check valve is provided with the filter for filtering the fluid, so that the operation of the valve body is well ensured. According to the fifth aspect, the solenoid valve is used as the valve device, so that the control can be performed easily and quickly.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a conventional engine choke valve control device.

FIG. 2 is a diagram showing the operation of the control device of FIG. 1 when the engine is started and the accelerator pedal is released after the vehicle has started.

FIG. 3 is a configuration diagram showing an embodiment of an engine choke valve control device according to the present invention.

FIG. 4 is a diagram showing the operation of the control device of FIG. 2 when the engine is started and the accelerator pedal is released after the vehicle has started.

5 is a cross-sectional view showing the configuration of the pressure-accumulation delay shown in FIG.

FIG. 6 is an explanatory view showing another example of use of the choke valve control device according to the present invention.

[Explanation of symbols]

 1 Intake passage 2 Throttle valve 3 Choke valve 4 Choke lever 5 Lever 6, 21 Choke breaker 9 Nozzle 10 Accumulation type delay 11 Main body 11b Orifice 12, 13 End plate 14 Valve body 15 Check valve 16, 17 Filter 18, 22 Boost hose 19 Three-way joint 20 Solenoid valve 23 Thermo valve

Claims (5)

[Claims] 1. An interlocking member that engages with a choke valve of an engine, a diaphragm connected to the interlocking member, and a diaphragm chamber partitioned by the diaphragm, and the interlocking member when a negative pressure acts on the diaphragm chamber. A member for displacing the choke valve in a valve opening direction; a communication passage having one end communicating with an intake passage downstream of the throttle valve and the other end communicating with the diaphragm chamber; and a communication passage provided in the communication passage, A choke valve control device for an engine, comprising: a check valve for blocking the flow of gas from one end side to the other end side; and a flow rate adjusting means provided in the communication passage for adjusting the flow rate of gas. 2. An atmosphere opening portion provided in the communication passage on the other end side of the check valve or in the diaphragm chamber, and a valve device opening the atmosphere opening portion when the engine is stopped. The choke valve control device for the engine according to. 3. The engine choke valve control device according to claim 1, wherein the check valve and the flow rate adjusting means are provided in the same chamber. 4. The engine choke valve control device according to claim 1, wherein the check valve includes a filter for filtering fluid. 5. The engine choke valve control device according to claim 2, wherein the valve device is a solenoid valve.