JP2519989Y2 - Vaporizer acceleration controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a carburetor for an engine, and more particularly to a carburetor acceleration control device for improving accelerating properties at low temperature without increasing fuel.

[Prior Art] Since the intake pipe is cold at low temperature, atomization of fuel introduced into the combustion chamber is poor, which causes a large response delay of fuel during acceleration, resulting in deterioration of drivability. In order to deal with this, in an engine having a carburetor, fuel is increased at the time of acceleration, but this method covers the amount of fuel that causes a response delay of the fuel, and thereby, the intake pipe is However, there is a problem that the remaining fuel increases and causes overrich during deceleration. The overrich causes an increase in the amount of discharged gas and causes smoldering of the plug, which causes a start failure due to the influence of the smoldering.

Therefore, in order to perform good acceleration at low temperatures,
An apparatus such as the one disclosed in Japanese Patent No. 61964 has been proposed. In this device, a sub-valve is provided downstream of the throttle valve in the intake passage, and the fuel introduced to the fuel chamber is reduced by reducing the flow passage cross-sectional area of the intake passage by the sub-valve during acceleration (high intake air amount). I try to increase the vaporization of.

[Problems to be Solved by the Invention] However, in the case of the device disclosed in the above publication, since the sub-valve is opened when a negative pressure is introduced into the diaphragm chamber of the actuator, a negative pressure introduction passage (generally, a hose or the like is used. If) is damaged, the atmosphere will enter the diaphragm chamber. Therefore, the sub-valve remains closed, and the sub-valve increases the flow passage resistance in the intake passage, which deteriorates the engine performance.

The present invention focuses on the above problems and improves the acceleration performance of the engine at low temperature, and even if the negative pressure introducing passage for introducing the negative pressure to the sub-valve driving actuator is damaged, the flow passage of the intake passage is made by the sub-valve. An object of the present invention is to provide an acceleration control device for a carburetor capable of preventing an increase in resistance.

[Means for Solving the Problem] An acceleration control device for a carburetor according to the present invention which meets this object is provided with a sub-valve with an adjustable opening degree downstream of a throttle valve, and the sub-valve is used for intake at the initial stage of acceleration at low temperature. In a carburetor acceleration control device for reducing the flow passage cross section of a passage, the sub-valve is connected to a control means for rotating the sub-valve in a valve closing direction by introducing a negative pressure in the intake passage.

[Operation] In the acceleration control device for the carburetor thus configured, the flow passage cross-sectional area of the intake passage is made small by the sub-valve at the initial stage of acceleration at low temperature. Therefore, a large negative pressure is provided on the downstream side of the sub-valve, and the vaporization property of the fuel in the intake passage is remarkably enhanced by the same principle as the depressurization boiling.

Further, since the control means for driving the sub-valve has a function of rotating the sub-valve in the valve closing direction by introducing the negative pressure, the negative pressure introducing passage for introducing the negative pressure to the control means is damaged, and the control means is controlled. Even if atmospheric air enters the sub-valve, the sub-valve can be rotated in the valve opening direction. for that reason,
A large flow passage cross-sectional area of the intake passage is secured, and flow passage resistance is prevented from increasing.

[Embodiment] A preferred embodiment of the carburetor acceleration control device according to the present invention will be described below with reference to the drawings.

1 to 3 show an embodiment of the present invention. In the figure, reference numeral 1 indicates an carburetor of an engine mounted on a vehicle. The carburetor 1 has a float chamber 2 for storing the fuel F, and a float 3 for adjusting the fuel level is arranged in the float chamber 2. The fuel in the float chamber 2 is measured by the main jet 4 and then ejected from the main nozzle 5. A throttle valve 6 that controls the amount of air-fuel mixture is provided on the downstream side of the main nozzle 5, and the throttle valve 6 is connected to an accelerator cable 7 that works together with an accelerator pedal (not shown).
A choke valve 8 that performs rich correction of the air-fuel mixture at low temperatures is provided on the upstream side of the throttle valve 6.

A sub valve 11 is provided on the downstream side of the throttle valve 6. The sub-valve 11 is composed of a butterfly valve, and its opening degree can be adjusted. In this embodiment, the sub-valve 11 is a housing that can be separated from the carburetor 1.
It is stored in 12. A lever 13 is directly connected to the sub valve 11, and the lever 13 is located outside the housing 12.

A control means 15 is connected to the lever 13 of the sub valve 11. The control means 15 is composed of a diaphragm type actuator 16, a temperature sensing valve 17, and a check valve (VTV) 18. The actuator 16 includes a rod 16a, a diaphragm 16b, a diaphragm chamber 16c, and a spring 16d. One side of the rod 16a is connected to the diaphragm 16b, and the other side of the rod 16a is connected to the lever 13 of the sub valve 11 described above. A spring 16d for urging the diaphragm 16b toward the rod 16a side is arranged in the diaphragm chamber 16c partitioned by the diaphragm 16b. The diaphragm chamber 16c of the actuator 16 can communicate with the inside of the intake passage 10 having a negative pressure via a temperature sensing valve 17 and a check valve 18 which are provided in the middle of the negative pressure introducing passage 20. In the present embodiment, negative pressure is introduced into the diaphragm chamber 16c from the port A located between the throttle valve 6 and the sub valve 11. Temperature sensitive valve 1
The 7 and the check valve 18 are connected in series, and one port of the temperature sensitive valve 17 is connected to the diaphragm chamber 16c. The temperature sensitive valve 17 has a function of guiding the atmosphere from the port B to the diaphragm chamber 16c after warming up and keeping the sub valve 11 fully open. Further, the check valve 18 has an orifice 18a inside, and performs a pressure delay operation (T) for fully opening the sub-valve 11 after a predetermined time of acceleration, and has a function of immediately opening the valve portion 18b during deceleration. Have.

In this embodiment, the sub-valve 11 driven by the actuator 16 has a diaphragm chamber as shown in FIG.
When the negative pressure introduced to 16c is smaller than a predetermined value, the sub-valve 11 is fully opened. Conversely, when the negative pressure becomes large,
It is rotated in the closing direction. For example, if air enters the diaphragm chamber 16c, the sub valve 11
It is rotated in the valve opening direction by the urging force of.

An adjusting screw 9 that can come into contact with the lever 13 is provided in the vicinity of the sub valve 11, and the position of the sub valve 11 in the valve closing direction can be variably adjusted by the adjusting screw 9.

Next, the operation of the acceleration control device for the carburetor will be described.

When the engine is started at low temperature, the temperature of the cooling water has not reached the predetermined temperature, and in this state, the temperature sensitive valve 17 connects the diaphragm chamber 16c and the port A. Since the check valve 18 is provided with the orifice 18a, even if the engine acceleration is started at a low temperature and the opening of the throttle valve 6 becomes large, the opening of the sub valve 11 does not immediately become large. Therefore, in this state, the negative pressure in the intake pipe on the downstream side of the sub-valve 11 becomes large, and the vaporization property of the fuel is enhanced by the same principle as the reduced pressure boiling. Therefore, atomization of the fuel introduced into the combustion chamber is promoted, and the acceleration performance at low temperatures is improved.
Then, a predetermined time after the acceleration is started, that is, the VTV18
When the delay operation of introducing the atmosphere into the diaphragm chamber 16c by the above is completed, the sub-valve 11 starts the opening operation as shown in FIG. After warming up, since the atmosphere is guided to the diaphragm chamber 16c by the operation of the temperature sensitive valve 17, the sub valve 11 is rotated in the fully open direction by the urging force of the spring 16d.

Thus, the sub-valve 11 is, as shown in FIG.
Since the closed state is maintained in advance to the extent that it does not hinder steady running, it is not necessary to consider the delay in closing the sub valve 11 immediately after acceleration, that is, immediately after the opening operation of the throttle valve 6. This makes it possible to further reduce the fall of the intake pipe negative pressure immediately after acceleration, which is advantageous for improving the acceleration performance.

Further, even if the negative pressure introduction passage 20 is damaged, the sub-valve 11 is forcibly opened by the urging force of the spring 16d, so that the reduction of the engine performance due to the reduction of the flow passage cross-sectional area of the intake passage 10 is prevented, and the normal running is performed. There is no hindrance to.

Further, in the case of the present embodiment, since the warm-up state of the engine is detected via the temperature sensitive valve 17 which senses the cooling water temperature, it is possible to more accurately detect the value close to the temperature of the intake pipe wall. it can. In addition, the acceleration state is detected by the intake pipe negative pressure that changes with the opening of the throttle valve 6, and the detected negative pressure is used to drive the sub-valve 11. Good and responsiveness can be improved.

[Effects of the Invention] As described above, in the acceleration control device for a carburetor according to the present invention, the sub-valve provided downstream of the throttle valve is rotated in the closing direction by introducing a negative pressure in the intake passage. Since the control means for moving is connected, the sub valve can be rotated in the valve opening direction even if, for example, the negative pressure introducing passage is damaged and the atmosphere enters the control means. Therefore, it is possible to prevent the flow passage cross-sectional area of the intake passage from being reduced by the sub-valve unlike the conventional device, and it is possible to prevent deterioration of engine performance due to an increase in flow passage resistance.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an acceleration control device for a carburetor according to an embodiment of the present invention, FIG. 2 is an operation characteristic diagram of a sub valve in the device of FIG. 1, and FIG. 3 is a throttle in the device of FIG. FIG. 6 is a characteristic diagram showing an operational relationship between a valve and a sub valve. 1 carburetor 6 ...... Throttle valve 10 ...... Intake passage 11 ...... Sub valve 15 ...... Control means 16 ...... Actuator 17 ...... Temperature sensing valve 18 ...... Check valve 20 ...... Negative pressure introduction passage

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takao Nonoyama 1 Toyota-cho, Toyota-shi, Aichi Toyota Motor Corporation (72) Inventor Masaharu Hayakawa 1-chome, 1-chome, Kyowa-cho, Obu-shi, Aichi Aisan Industry Within the corporation

Claims (1)

(57) [Scope of utility model registration request] 1. An acceleration controller for a carburetor, wherein a sub-valve whose opening can be adjusted is provided downstream of a throttle valve to reduce the flow passage cross section of an intake passage by the sub-valve at the initial stage of acceleration at low temperature. An acceleration control device for a carburetor, characterized in that a control means for rotating the sub-valve in a closing direction by introducing a negative pressure in the intake passage is connected.