CN1313462A - Automatic choke control - Google Patents

Abstract

An automatic choke control device is provided, which can improve the control precision without increasing the cost. When the engine speed detected by the speed detection sensor 49 is equal to or higher than the set speed, the microcomputer 46 controls the energization time of the PTC type heater 42 as the auto choke heater by the pulse control of the transistor 47, so that the external resistor for adjusting the voltage applied to the auto choke heater, which has been conventionally used, can be eliminated. When such an automatic choke valve is applied to engines having different characteristics, the width of the on pulse in the microcomputer 46 can be changed according to the characteristics of the engine to be used, so as to correspond to the engine having various characteristics.

Description

Automatic choke control

The present invention relates to an automatic choke control device, and more particularly to an automatic choke control device capable of easily changing the energization time of a heater for an automatic choke.

Among the carburetors of the vehicle, there is a carburetor equipped with an automatic choke valve, which automatically obtains good starting and warm-up operation according to the outside air temperature and the engine warm-up state. In the automatic choke, there is a heater for the automatic choke, which is provided integrally with the carburetor.

The automatic choke equipped with a heater for the automatic choke applies a part of the voltage generated by the flywheel type permanent magnet generator to the heater for the automatic choke to heat the ceramic plate. Furthermore, the hot wax is expanded by the heat of the ceramic plate, and the starting plunger is operated to adjust the fuel supply amount.

As an example showing this kind of automatic choke control device, for example, in Japanese Patent Application Laid-Open No. 8-42398, the resistance value of the resistor for voltage adjustment as an external resistor is variable, and the voltage applied to the heater for automatic choke is adjusted. Voltage.

That is, as shown in FIG. 8, one end of the heater 1 for the automatic choke valve is connected to the control transistor 3 via the resistor 2 for voltage adjustment. The automatic choke heater 1 is a heater that uses heat to expand hot wax that performs a closing operation of a starter plunger (not shown). In addition, the resistor 2 for voltage adjustment has a predetermined resistance value in order to adjust the voltage to the heater 1 for automatic choke valves.

The control transistor 3 inputs the ignition signal of the ignition coil 4a of the three-phase magnet 4 as the engine speed, and applies a voltage to the automatic choke heater 1 side when the engine speed is input. An ignition spark plug 6 is connected to the ignition coil 4a via a capacitive discharge igniter (CDI) 5 .

In addition, on the other side of the automatic choke heater 1 , a three-phase magnet 4 is connected via a regulator 7 . A battery 9 is provided between the automatic choke valve heater 1 and a light switch 8 for turning on a lamp 8a.

In this configuration, when the engine speed is input to the control transistor 3 when the engine is started, a voltage is applied to the automatic choke valve heater 1 due to the conduction operation of the control transistor 3 . At this time, since the voltage applied to the automatic choke valve heater 1 can be lowered by adjusting the voltage with the voltage adjusting resistor, the expansion of the thermal wax (not shown) becomes slow. As a result, since the closing operation of the unillustrated starter plunger is performed slowly, sudden changes in the fuel supply amount can be avoided, and the occurrence of engine stall can be prevented.

However, in the above-mentioned conventional automatic choke control device, the voltage applied to the automatic choke heater 1 is adjusted by using the voltage adjustment resistor 2 which is an external adjustment resistor. In this case, since the resistance value of the resistor 2 for voltage adjustment is constant, it is necessary to set a resistance value consistent with the characteristics of the installed engine. Resistor 2, for voltage adjustment. Therefore, if the solution is to replace the resistor 2 for voltage adjustment of this kind, there is a problem of causing an increase in cost.

In addition, if the voltage applied to the heater 1 for automatic choke is adjusted only by the resistor 2 for voltage adjustment, since the resistance value of the resistor 2 for voltage adjustment is constant, the automatic choke control that adapts to the engine temperature cannot be performed. , Therefore, there is also the problem that the mixed gas is temporarily too rich to waste fuel, and on the contrary, the mixed gas is too lean to increase the warm-up time, which reduces the accuracy of the automatic choke valve control.

The present invention is proposed in view of this situation, and provides an automatic choke control device that can improve the control accuracy of the automatic choke without increasing the cost.

The automatic choke valve control device of claim 1 is an automatic choke valve heating device that uses a battery as a power source to heat and expand a sliding throttle valve for driving the opening and closing of a fuel passage for starting a carburetor. At the same time, the automatic choke control device for controlling the electric energization of the heater for the automatic choke from the above-mentioned battery is characterized in that it includes a pulse control device. Use heater energization time.

Further, the pulse control device may include: a transistor for intermittently energizing the automatic choke valve heater from the battery; and a microcomputer for applying an ON pulse with a modulated pulse width to a base of the transistor.

In addition, the above-mentioned microcomputer adjusts the width of the above-mentioned on-on pulse according to the engine temperature detected by the temperature detection sensor. When the detection temperature is low, the width of the on-pulse to the base of the transistor is reduced.

In the automatic choke control device of the present invention, instead of using an external resistor to adjust the voltage applied to the heater for the automatic choke, a pulse control device is used to control the heating to the heater for the automatic choke when the engine speed is above the set speed. At the same time, the width of the on-pulse is variable according to the detected temperature.

Fig. 1 is an equivalent circuit diagram showing an embodiment of the automatic choke control device of the present invention.

Fig. 2 is a diagram for explaining the operation of the automatic choke valve control device of Fig. 1 .

Fig. 3 is a view showing an example of an engine of a motorcycle to which the automatic choke control device shown in Fig. 1 is applied.

FIG. 4 is a sectional view showing the automatic choke of FIG. 3 .

FIG. 5 is a cross-sectional view showing the automatic choke valve of FIG. 4 along line a-a.

Fig. 6 is a cross-sectional view showing a specific configuration of the automatic choke door of Fig. 4 .

FIG. 7 is a diagram showing another embodiment of the automatic choke control device of FIG. 1 .

FIG. 8 is an equivalent circuit diagram showing an example of a conventional automatic choke valve control device.

Embodiments of the present invention will be described below.

Fig. 1 is an equivalent circuit diagram showing one embodiment of the automatic choke control device of the present invention, Fig. 2 is a diagram for explaining the operation of the automatic choke control device in Fig. 4 to 6 are diagrams showing an automatic choke valve installed on the carburetor shown in FIG.

First, an engine to which the automatic choke valve control device of FIG. 1 is applied will be described with reference to FIGS. 3 to 6 .

Inside the cylinder block 10 of the engine shown in FIG. 3 , a piston 12 connected to a connecting rod 11 is provided. On the upper portion of the cylinder block 10, a cylinder head 15 is provided between the piston 12 and a combustion chamber.

The cylinder head 15 is provided with an intake valve 18 and an exhaust valve 19 which are opened and closed by a camshaft 16 and a rocker arm 17 . In addition, an intake manifold 20 is connected to the cylinder head 15 . The intake manifold 20 is provided with a carburetor 21 that generates an air-fuel mixture that is fed into the combustion chamber.

On the other hand, in the carburetor 21 , for example, an automatic choke valve 22 as shown in FIG. 4 is provided. On the automatic choke valve 22 shown in FIG. 4 , a starting fuel adjustment device A and a temperature-sensitive driving device B are provided. Further, on the starting fuel adjustment device A, a starting air passage 28 and a starting mixed gas passage 29 are provided.

In addition, the air passage 28 for starting, for example, as shown in FIG. The downstream side of flow valve 26. Further, between the starting air supply passage 28 and the starting mixed gas passage 29 , a slide throttle valve 31 of the starting fuel adjustment device A is provided, and the slide throttle valve 31 is communicated with the float chamber 24 .

The specific configurations of the starting fuel adjusting device A and the temperature-sensitive driving device B of the automatic choke valve 22 in FIG. 4 are as shown in FIG. 6 . That is, the starting fuel adjusting device A is installed on the carburetor main body 23 , and the temperature-sensitive driving device B is installed on the upper side of the starting fuel adjusting device A.

At the lower part of the carburetor main body 23, a starting well 25 communicating with the float chamber 24 is provided. In addition, the carburetor main body 23 is provided with the above-mentioned starting air-fuel mixture passage 29 built therein.

A metering needle valve 33 incorporated in a starting fuel nozzle 32 is attached to the slide throttle valve 31 of the starting fuel adjusting device A. As shown in FIG. The sliding throttle valve 31 is loaded downward by the spring 35 interposed between it and the fixed ring 34 on the side of the temperature-sensitive driving device B.

A case 38 housing a piston 36 and a fluid substance 37 such as rubber or silicone is incorporated in the fixed ring 34 . A cap 40 for accommodating thermal wax 39 is attached to the housing 38 . The fluid 37 and the hot wax 39 are separated by a diaphragm 41 .

A PTC heater 42 , which is an automatic choke heater of the automatic choke control device that expands the hot wax 39 by heat, abuts against the upper portion of the cap 40 . Power is supplied to the PTC type heater 42 through a female connector 45 connected to the terminals 43 , 44 .

That is, the automatic choke control device includes, as shown in the equivalent circuit diagram of FIG. Here, the pulse control means is constituted by the microcomputer 46 and the transistor 47 .

The rotational speed detection sensor 49 supplies the ECU 48 with a detection signal from ACG or the crank pulse generator 81 generated when the engine rotates. The temperature detection sensor 50 detects the engine temperature (the temperature in the water-cooling jacket), and sends the detection signal to the ECU 48 .

One end of the PTC heater 42 is connected to a power line 51 connected to a storage battery (not shown). The other end of the PTC heater 42 is connected to the terminal side of the transistor 47 . A PWM-controlled (pulse width modulation) on pulse is applied by the microcomputer 46 to the base of the transistor 47 .

The microcomputer 46, for example, when the engine speed obtained by the speed detection sensor 49 is above the set speed, applies the on-pulse 51a of the width after PWM (pulse width modulation) shown in FIG. 2 to the base of the transistor 47, so that Transistor 47 is turned on.

That is, such PWM (Pulse Width Modulation) control operates according to the characteristics of the engine according to the preprogrammed operation, so that the characteristics of the engine during the warm-up operation show the same characteristics for the same model.

Hereinafter, the operation of the automatic choke valve control device having such a configuration will be described.

First, when the engine is started, the thermal wax 39 shown in FIG. 6 is in an expanded state corresponding to the ambient air temperature, and the protrusion amount of the piston 36 from the housing 38 also corresponds to the ambient air temperature. Accordingly, the operating position of the slide throttle valve 31 also corresponds to the ambient air temperature.

In this state, when the main switch (not shown) is turned on and the engine is turned at the starting position, the fuel supplied to the engine is supplied to the engine through the starting air passage 28 and the starting air mixture passage 29 as the starting fuel passage. The concentration of the mixed gas becomes rich, and the engine is easy to start cold.

When the engine is started, the rotational speed is detected by the rotational speed detection sensor 49. If the rotational speed is above the set rotational speed, the microcomputer 46 shown in FIG. 1 controls the drive transistor 47 by PWM (pulse width modulation). As a result, the transistor 47 is turned on, and the current from the power supply line 51 is supplied to the PTC heater 42 .

At this time, due to the heat from the PTC heater 42, the volume of the hot wax 39 shown in FIG. Then, when the warm-up operation of the engine ends, the starting fuel nozzles 32 are all closed. As a result, the amount of fuel supplied to the engine through the starting air passage 28 and the starting air-fuel mixture passage 29 as the starting fuel passage decreases as the warm-up state progresses, and becomes equal to the required mixture concentration.

Furthermore, during engine warm-up, if the engine temperature (temperature in the water-cooling jacket) rises, the temperature is detected by the temperature detection sensor 50 . Therefore, even when the engine is stopped during warm-up, the microcomputer 46 can control the driving of the sustain transistor 47 by the aforementioned PWM (pulse width modulation) when the engine temperature is equal to or lower than a predetermined value.

Then, after the engine is stopped, when the engine temperature is high and restarted, fuel is not supplied through the starting air passage 28 and the starting mixed gas passage 29 as the starting fuel passage, and the concentration of the mixed gas supplied to the engine is the same as that of the normal operation. It is the same at the same time, which is consistent with the required concentration of the mixed gas.

Also, after the engine stops, if the engine temperature drops below a predetermined value, the hot wax 39 gradually shrinks, and the state of the starting fuel nozzle 32 closed by the metering needle valve 33 is gradually released. Therefore, when the engine is restarted after a considerable period of time has elapsed after the engine has been stopped, the concentration of the air-fuel mixture increases similarly to the above-mentioned startup of the ambient air temperature.

In this way, in this embodiment, because it is set to be controlled by the pulse of the transistor 47 by the microcomputer 46, when the engine speed detected by the speed detection sensor 49 is above the predetermined speed, the control is directed to the PTC type heater as an automatic choke valve heater. The energization time of the heater 42 is reduced, so the external resistor used in the past to adjust the voltage applied to the automatic choke valve heater can be eliminated. Furthermore, when this automatic choke is applied to engines with different characteristics, it is easy to respond by changing the on-pulse width in the microcomputer 46 according to the characteristics of the used engine, and cost increase can be avoided.

In addition, the automatic choke control using the PWM (pulse width modulation) control of the transistor 47 can reduce the variation in the automatic choke operating time compared with the conventional voltage adjustment using an external resistor. This is because the PWM (pulse width modulation) control of the transistor 47 is smaller than the variation in the resistance value of the conventional external resistor.

Furthermore, in this embodiment, when the engine speed is above the set speed, the pulse control of the transistor 47 is used to control the energization time of the PTC heater 42, but it is not limited to this example, and it can also be used with The detection signal from the temperature detection sensor 50 which detects the temperature of the engine is combined to control the PWM (Pulse Width Modulation) of the transistor 47 .

In this case, for example, as shown in FIG. 7 , the microcomputer 46 has a map showing the relationship between the detected temperature and the width of the ON pulse 51 a supplied to the base of the transistor 47 . Furthermore, when the temperature detected by the temperature detection sensor 50 is high, since the width of the ON pulse 51a supplied to the base of the transistor 47 is widened, the automatic choke control time can be shortened.

In addition, when the temperature detected by the temperature detection sensor 50 is low, by reducing the width of the ON pulse 51a supplied to the base of the transistor 47, the automatic choke control time can be increased. As a result, the automatic choke valve control accuracy can be improved because there is no situation where the mixture gas is temporarily rich to waste fuel, or conversely, the time required for warming up the machine is increased when the mixture gas becomes lean.

In addition, when detecting the engine temperature, a method of directly detecting the temperature of a cylinder body such as a cylinder block and a cylinder head, or a method of detecting the temperature of cooling water in a water-cooled engine may be used. In addition, by using a FET (Field Effect Transistor) for the transistor 47, the output of the automatic choke valve control device can be improved, and the versatility can be further improved.

As mentioned above, if the automatic choke valve control device of the present invention is adopted, because it is set so as not to use an external resistor for adjusting the voltage applied to the heater for the automatic choke valve, but to use a pulse control device, when the engine speed is above the set speed, , the pulse control is applied to the heater for the automatic choke valve. At the same time, the width of the ON pulse can be changed according to the detected temperature. Therefore, the accuracy of the automatic choke valve control can be improved without causing an increase in cost.

Claims (3)

1. automatic choke valve controlling device, possesses the Choke Openner heater that as power supply the hot wax heating of the sliding throttle valve of the switching that is used to drive the starting fuel path that carries out Carburetor is made its expansion with storage battery, and control is characterized in that: comprise from the energising of above-mentioned storage battery to above-mentioned Choke Openner usefulness heater

Pulse control unit, it is setting rotating speed when above when engine speed, and pulse control storage battery is to the energising of above-mentioned Choke Openner with heater.

2. automatic choke valve controlling device as claimed in claim 1 is characterized in that:

Above-mentioned pulse control unit possesses:

Transistor is intermittently used the energising of heater to above-mentioned Choke Openner from above-mentioned storage battery;

Microcomputer applies by the make pulse after the Sampling above-mentioned transistorized base stage.

3. automatic choke valve controlling device as claimed in claim 2 is characterized in that:

Above-mentioned microcomputer, according to temperature from the detected engine of temperature detection sensor, adjust the width of above-mentioned make pulse, make the variable-width of above-mentioned make pulse, make when above-mentioned detected temperatures is high, increase the width be applied to the make pulse on the above-mentioned transistorized base stage, when above-mentioned detected temperatures is low, reduce to impose on the width of the make pulse of above-mentioned transistorized base stage.

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