JPS6038546B2 - Engine startability improvement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to a carburetor, and more particularly to an engine startability improving device incorporated in a carburetor.

The carburetor in a car is cooled by the running wind, intake air, fuel vaporization heat, etc. while the engine is running, but when the car is idling or the engine is stopped after driving, the running wind disappears and the engine compartment and Since the engine body becomes hot, naturally the carburetor also becomes hot, and the fuel in the carburetor also becomes hot, and the intake passage becomes filled with a rich air-fuel mixture due to fuel vapor and percolation.

If you try to restart the engine in such a case, fuel from the carburetor's slow fuel system will be added to the rich mixture described above, creating an even richer mixture that exceeds the flammable air-fuel ratio. As a result, restartability becomes poor, and sometimes restarting becomes impossible. When the fuel is in a high temperature state, the intake passage is filled with a rich mixture, so there is no need for fuel to be supplied from the slow system when starting the engine, and as mentioned above, fuel is supplied from the slow system at such times. Not only does this impair starting performance, but it is also uneconomical in terms of fuel consumption. The main purpose of the present invention is to improve the startability of an engine when the fuel temperature is high.More specifically, in order to achieve the above main purpose, the present invention aims to The detailed objective is to improve the slow fuel supply system.

These objects, according to the present invention, include a valve device provided in the middle of a fuel passage leading to a slow boat and an idle boat of a carburetor to selectively shut off the passage; a temperature sensor that senses the temperature at which the ignition switch is operated; and a control device that controls the operation of the valve device to open the valve device only when the ignition switch is closed based on the operation of the ignition switch. The control device further responds to the operation of the temperature sensor, and when the temperature sensed by the temperature sensor is above a predetermined value, the control device further controls the temperature to be substantially lower than when the temperature sensed by the temperature sensor is below the predetermined value. This is achieved by an engine startability improving device which operates to delay the opening of the valve device by a significantly longer period of time than the closing of the ignition switch.

With this configuration, fuel from the slow fuel supply system is temporarily cut off when the engine is started when the fuel temperature is high, thereby preventing the air-fuel mixture in the intake passage from becoming even richer due to percolation or the like due to slow fuel. The mixture is used to start the engine, and the engine can then continue to operate normally using fuel from the slow fuel supply system that is supplied with a delay.

As the valve device, in order to prevent run-on when the engine is stopped, a solenoid valve conventionally provided in the middle of the fuel passage leading to the slow boat and idle boat of the carburetor can be used as is. The present invention can be implemented relatively easily even in conventional vaporizers by simply providing a sensor and a control device.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings.

The attached figure is a sectional view showing one embodiment of the startability improving device according to the present invention.

In the figure, 1 is a carburetor body, and a throttle valve 3 is provided in an intake passage 2 passing through the carburetor body. As shown in the figure, there is a strip at a position opposite to one end of the throttle valve 3 which is in the closed position. - port 4 is provided, and an idle boat 5 is provided somewhat downstream from this port. These slow boats 4 and idle boats 5 are supplied with fuel from a float chamber 8 through a slow fuel passage 7 which is branched from the main fuel passage 6 midway. A float 9 is disposed within the float chamber 8, and fuel supplied to a fuel intake port 101 is introduced through a needle valve device 11 controlled by the float 9. The fuel in the float chamber 8 flows out from the main jet 12, passes through the main fuel passage 6, and is mainly supplied to the main nozzle that opens into the venturi section (not shown in the figure), and a part of it flows into the slow fuel passage. 7, and is supplied to the slow boat 4 and idle boat 5 while its flow rate is adjusted by a slow jet 13 provided along the way. Further, the fuel flow rate from the idle boat 5 is adjusted by an adjustment screw 14.
Further, in the carburetor body 1, a valve seat 15 and a needle valve body 1 are provided across the middle of the slow fuel passage 7.
A solenoid valve 17 including 6 is provided.

When the electromagnetic valve 17 is energized, the needle valve body 16 is raised upward as shown in the figure to establish operation of the slow fuel passage 7, whereas when it is not energized, it is pushed down as shown in the figure. It is configured to block the flow of the slow fuel passage 7. The electromagnetic valve 17 is selectively supplied with current from a battery power source 18 via an ignition switch 19 and a control device 20 such as a computer. The control device 20 should sense the temperature of the fuel in the float chamber 8 (receives a temperature signal from the temperature sensor 21 attached to the carburetor body, and if the temperature signal is above a predetermined value, the ignition is activated). switch 19
and the solenoid valve 17 are connected through a delay circuit within the control device 20, and if the temperature signal is below a predetermined value, the two are directly electrically connected. The delay circuit is configured to remain open until several seconds have elapsed after the ignition switch 19 is closed, and then close the circuit. When the fuel temperature in the float chamber 8 is not very high and percolation does not occur, closing the ignition switch 19 closes the solenoid valve 1.
7 is immediately energized, and the solenoid valve 17 establishes full communication of the slow fuel passage 7.

Therefore, at this time, the fuel in the float chamber 8 flows through the slow fuel passage 7 to the slow boat 4 or the idle boat 5, and the fuel necessary for starting is secured. When the fuel temperature in the float chamber 8 is high and a relatively rich mixture exists in the intake passage 2 due to fuel vapor or percolation, the temperature sensor 21 detects that the fuel temperature is high. It senses and transmits the signal to two control devices.

When the ignition switch 19 is closed to start the engine in such a state, the delay circuit of the control device 20 suspends the energization of the solenoid valve 17 and maintains its de-energized state. The slow fuel passage 7 continues to be blocked. Therefore, in such a case, no fuel is supplied from the slow boat 4 or the idle boat 5, and the engine is started using the air-fuel mixture that has filled the intake passage 2. When a predetermined time determined by a delay circuit of the control device 20 after the ignition switch 19 is closed, preferably a time period during which the air-fuel mixture filling the intake passage 2 is consumed, the control device 20
The solenoid valve 17 is energized by the action of the solenoid valve 17, and the solenoid valve 17 establishes the operation of the slow fuel passage 7. Therefore, at this time, fuel is supplied from the slow boat 4 or the idle boat 5 into the intake passage 2, and the engine continues to operate with the fuel. From the above description, it will be understood that the engine startability improving device according to the present invention can be easily implemented by effectively utilizing the run-on prevention valve device, and exhibits excellent performance.

BRIEF DESCRIPTION OF THE DRAWINGS The attached drawing is a sectional view showing one embodiment of the engine startability improving device according to the present invention. 1-Carburetor body, 2-Intake passage, 3-Throttle hull, 4-Slow boat, 5-Idle boat, 6-Main fuel passage, 7-Slow fuel passage, 8-Float chamber, 9
~Float, 10~Fuel intake, 11~Needle valve device, 12~Main jet, 13~Slow jet, 1
4 ~ Adjustment screw, 15 ~ Valve seat, 16
~ Needle valve body, 17 ~ Solenoid valve, 18 ~ Battery power supply,
19~ignition switch, 20~control device, 21
~Temperature sensor.

Claims (1)

[Claims] 1. A valve device provided in the middle of a fuel passage leading to the slow port and idle port of the carburetor to selectively shut off the passage, and a temperature sensor that senses a temperature representative of the fuel temperature in the float chamber of the carburetor. a control device that controls the operation of the valve device so as to open the valve device only when the ignition switch is closed based on the operation of the ignition switch; In response to the operation of the temperature sensor, when the temperature sensed by the temperature sensor is above a predetermined value, the ignition switch is closed for a substantially longer time than when the temperature sensed by the temperature sensor is below the predetermined value. 1. A device for improving startability of an engine, characterized in that the device operates to delay the point in time when the valve device opens from the point in time when the valve device opens.