JPS6323376B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in valve opening control during warm-up operation of a choke valve and a throttle valve of a carburetor.

Generally, the valve opening control device for the carburetor of an internal combustion engine such as an automobile uses an electrothermal choke mechanism, that is, a heat generating member such as a nichrome wire that generates heat due to the power supplied from an on-board battery, and a bimetal that physically deforms due to the heat generated by the heat generating member. A mechanism that controls the opening and closing operations of the throttle valve by physically deforming the temperature sensing member, and a mechanism that controls the opening and closing operations of the throttle valve to increase the idle to speed up warm-up. It is equipped with a fast idle mechanism to control the engine.

By the way, improving fuel efficiency in automobiles and the like has recently become an important issue, and one method of achieving fuel efficiency improvement is being considered to improve fuel efficiency by opening the chiyoke valve as early as possible.

However, in the conventional carburetor valve opening control device, (1) the electrothermal choke mechanism is configured to receive power directly from the battery via the engine key switch, and (2) the first・Because the idle mechanism is connected to the electrothermal choke mechanism mentioned above through a power transmission means such as a lever or cam, the configuration of the electrothermal choke mechanism was changed in order to open the choke valve earlier. Even so, it is difficult to satisfactorily achieve the different required characteristics of the chiyork valve opening at room temperature and low temperature, and the early opening of the chiyork valve can easily cause the above-mentioned first idle mechanism to malfunction. In the case of
It has been difficult to achieve a sufficient improvement in fuel efficiency because the valves are released undesirably early and the engine malfunctions.

The present invention aims to solve the above points,
The aim is to achieve sufficient fuel efficiency improvement with a simple configuration. Therefore, the valve opening control device for a carburetor of the present invention changes the opening characteristics of the choke valve and throttle valve during warm-up operation depending on the atmospheric temperature, so that the To ensure stable warm-up characteristics even when the temperature changes dramatically, or even when the same car is used in frigid Alaska or tropical Africa, each temperature is controlled by the output of a temperature sensor that detects atmospheric temperature. It is characterized by individually controlling the duty ratio of the valve-driven heaters for heating the temperature-sensitive member.

Next, the configuration of an embodiment of the present invention will be explained with reference to the drawings.

Fig. 1 is an overall configuration diagram of the valve opening control device for a carburetor according to this embodiment, Fig. 2 is a cross-sectional view of the actuator shown in Fig. 1, and Fig. 3 is the control circuit section shown in Fig. 1. FIG. 4 is an electrical circuit diagram specifically showing the control circuit section, and FIGS. 5 and 6 are
The figures show duty ratio-atmosphere temperature characteristic diagrams for the choke system and first idle system, respectively, and FIG. 7 shows the valve opening degree curve obtained in this example.

In FIG. 1, 100 is the vaporization main body, 200
300 is a battery installed in a vehicle and is grounded to the body; 40 is a control circuit section;
0 is an actuator that is a component of the fast idle mechanism, 500 is a temperature sensor that detects the atmospheric temperature, 600 is a key switch, and 101 is a throttle valve that adjusts the amount of fuel sucked by its opening and closing operations. , 102
is a lever that is engaged with the throttle valve and is connected to the shaft 40 of the actuator 400.
1 is configured to be rotatable by axial movement; 103 is a chiyoke valve which limits the amount of air supplied into the carburetor body 100 by opening and closing operations; 104 is a shaft; 103 and is configured to be rotatable in the direction of arrow B in the figure; 105 is the first
The temperature sensing member 106 is made of a coiled bimetal, for example, and the first heat generating member 106 is a nichrome wire resistor, a ceramic resistor or
Those composed of PTC heaters, etc., 10
7 is a power transmission means and the first temperature sensing member 10
108 and 109 are lead wires that supply power from the control circuit section 200 to the first heat generating member 106; A float, 111 is a liquid fuel such as gasoline, 112 is a main nozzle, 113 is a slow port, 114 is an idle port, 401 is a shaft of the actuator 400, and 402 is a lead wire that connects the output of the control circuit 200 to the actuator. 400 respectively.

The internal structure of the actuator 400 is as shown in FIG. In Figure 2, 4
01 is the shaft corresponding to the symbol in FIG. 1, 402
403 is a first storage case, 403 is a second storage case that is fitted into the first storage case 402, and 404 is a second heat generating member, which is a nichrome wire resistor, a ceramic resistor, or a PTC heater. 405 is a second temperature-sensitive member made of bimetal or wax-type displacement member, 406 is a terminal portion to which the lead wire shown in FIG. 1 is connected, and 407 is an electrode. Each represents a board.

When the key switch 600 is turned on to start the engine, the control circuit section 200 turns on the battery 3.
00 to a corresponding power level based on the detected output by the temperature sensor 500, and the reduced power is applied to the lead wire 10 on the one hand.
8, 109 to the first heat generating member 106 of the electrothermal choke mechanism;
02, the heat is supplied to the second heat generating member 404 of the fast idle mechanism via the terminal portion 406 and the electrode 407.

The first heat-generating member 106 that receives the electric power starts generating heat, and the generated thermal energy causes the first temperature-sensitive member 1 disposed close to the heat-generating member 106 to emit heat.
05 undergoes physical deformation, and in accordance with the deformation action of the temperature sensing member 105, the check valve 105, which is in a fully closed state before starting the engine, begins to open.

On the other hand, the second heat-generating member 404 starts generating heat due to the power supply, and the second temperature-sensitive member 405 disposed close to the heat-generating member 404 is contracted in the axial direction of the shaft 401 by the thermal energy. In response to the contraction, the shaft 401 connected to the temperature sensing member 405 starts moving in the direction of arrow A shown in FIGS.
2, the throttle valve 101 starts its closing operation from the throttle valve opening depending on the ambient temperature before starting the engine.

Here, the throttle valve opening degree before starting the engine is set to a value corresponding to the ambient temperature (for example, a value as shown in Fig. 7) so that an appropriate amount of fuel can be supplied to the engine room according to the ambient temperature. It is set in advance, and this initial setting is determined mainly based on the deformation state of the second temperature sensing member 405 according to the ambient temperature before starting the engine.

Note that when the key switch 600 is turned on, the engine is started at the same time as power supply to the electric heating type choke mechanism and the above-mentioned fast idle mechanism is started, and the negative pressure generated by starting the engine causes the fuel 11 to be turned on.
1 is slow port 113 and idle port 1
14 and is supplied to the engine room.

The control circuit section 200 has a configuration as shown in FIG.

In the figure, 200, 300, 500, 600, 10
6 and 404 correspond to the same symbols in FIGS. 1 and 2, respectively, 201 is an amplifier, and 2
02 is an attenuator, 203 is a triangular wave oscillator, 20
4 is the first comparator, 205 is the second comparator, 20
6 is a stabilized power supply circuit, 207 is a first power circuit,
208 represents second power circuits, respectively.

In FIG. 3, a temperature sensor 500 is composed of, for example, a thermistor whose resistance value decreases as the ambient temperature rises (hereinafter, the temperature sensor 500 will be appropriately referred to as a thermistor 500).
The 0 output is amplified by the amplifier 201, and the amplified output is input to one input terminal of the first comparator 204, and the amplified output is input to the attenuator 202.
The attenuated signal is input to one input terminal of the second comparator 205,
04, the amplified output and the triangular wave oscillator 203
At the same time, the second comparator 205 processes the attenuated output and the reference output with a duty ratio, and the duty ratio changes from the first comparator 204 shown in FIG. The first power circuit 207 is controlled by the corresponding on/off output to determine the amount of power to be supplied from the battery 300 to the first heat generating member 106, and the output from the second comparator 205 shown in FIG. The battery 300 is controlled by controlling the second power circuit 208 with on/off output corresponding to changes in duty ratio.
The amount of power to be supplied to the second heat generating member 404 is determined from. Note that the stabilized power supply circuit 206 uses a reference voltage
The reference voltage V0 is applied to the amplifier 201, the oscillator 203, and the like.

FIG. 4 shows an example of an electric circuit specifically representing the control circuit section 200 having a block configuration as shown in FIG. R1 to R21 each represent a switching transistor, R1 to R21 each represent a resistor, C represents a capacitor, and other symbols correspond to the same symbols in FIG.

The processing and operation of the circuit will be described below, taking as an example the case where the ambient temperature is low when the key switch 600 is turned on.

When the key switch 600 is turned on, a preset reference voltage V0 is output from the stabilized power supply circuit 206, and the amplifier 201 and the triangular wave oscillator 20
Supplied to 3rd class.

Therefore, current is supplied to the thermistor 500 via the resistor R1 of the amplifier 201, and the thermistor 500
A high voltage, that is, a thermistor high output voltage, is generated at the 0 output terminal due to the high resistance of the thermistor 500 based on the low ambient temperature, and the thermistor high output voltage is input to the inverting input terminal side of the operational amplifier A1 via the resistor R4, R2, resistor R3 and resistor R5
The divided voltage of the reference voltage V0 input to the other non-inverting input terminal side is subjected to operational amplification processing in the operational amplifier A1, and a low-level amplified voltage is output from the operational amplifier A1. Then, it is input to the non-inverting input terminal side of the operational amplifier A4 via the resistor R16 of the first comparator 204, and on the other hand, it is divided by the resistors R7 and R8 of the attenuator 202 and converted to a low-level divided voltage. The signal is inputted to the non-inverting input terminal side of the operational amplifier A5 via the resistor R18 of the second comparator 205. On the other hand, the oscillator 203 to which the reference voltage V0 is applied generates a preset reference signal, for example, a reference triangular wave voltage signal. R17, R19
The signal is input to the respective inverting input terminals of operational amplifiers A4 and A5.

The operational amplifier A4 of the first comparator 204 performs operational amplification processing on the low-level amplified voltage and the reference triangular wave voltage signal, and outputs the switching transistor TR.
1 performs a switching operation in which the ratio of the on period to the off period (duty ratio) is small in accordance with the control voltage of the transistor RT1, and low level power is supplied to the first heat generating member 106. Further, the operational amplifier A5 of the second comparator 205 performs operational amplification processing on the low-level divided voltage and the reference triangular wave voltage signal, and similarly to the above case, the switching transistor TR2 has a small on-off ratio. A switching operation is performed, and low level power is supplied to the second heat generating member 404.

When the ambient temperature rises as the engine rotates, the thermistor 5 responds to the temperature rise.
00 resistance decreases, and as the resistance decreases, the thermistor 500 output voltage gradually decreases.

Therefore, the output voltage of the amplifier 201 increases from the low level amplified voltage at low ambient temperature, the divided voltage by the attenuator 202 increases, and both the switching transistor TR1 and the switching transistor TR2 are As shown in FIG. 6, a switching operation is performed in which the duty ratio tends to increase, and the amount of power supplied to the first heat generating member 106 and the second heat generating member 404 increases.

In this way, as the ambient temperature rises, both the duty ratio of the switching transistor TR1 and the duty ratio of the other switching transistor TR2 increase, and the duty ratio of the switching transistor TR1 increases.
The duty ratio characteristic of transistor TR1 is as shown in FIG. 5, for example, and the duty ratio characteristic of the other transistor TR2 is as shown in FIG. 6, for example.

Under predetermined conditions, the choke valve opening characteristic and the throttle valve opening characteristic obtained using the control circuit section 200 as shown in FIG. 4 are as shown in FIG. 7.

Next, the effects of the present invention will be explained.

The present invention provides a carburetor equipped with a throttle valve whose valve opening is controlled by a first temperature-sensitive member and a throttle valve whose valve opening at first idle is controlled by a second temperature-sensitive member. In the device, the first heat-generating member heats the first temperature-sensitive member to displace the throttle valve from the closed state to the open state, and the second heat-sensitive member heats the throttle valve to open the throttle valve. a second heat generating member that is displaced in the valve closing direction from the state, a temperature sensor that generates an output corresponding to the ambient temperature around the vaporizer, and a reference voltage determined based on the output from the temperature sensor and a voltage from an oscillator. a first comparator that receives a triangular wave voltage signal and generates an output signal with a duty ratio corresponding to the output from the temperature sensor; and a reference voltage and oscillator that are determined based on the output from the temperature sensor. from 3
a second comparator that receives a square wave voltage signal and generates an output signal with a duty ratio corresponding to the output from the temperature sensor; and a second comparator that generates an output signal with a duty ratio corresponding to the output from the temperature sensor; a first power circuit that supplies the first heat generating member; and a second power circuit that supplies the second heat generating member with power corresponding to the duty ratio output signal from the second comparator. This is in a valve opening control device for a vaporizer equipped with.

As a result, the present invention changes the opening characteristics of the throttle valve and the throttle valve during warm-up operation depending on the atmospheric temperature. Moreover, even if the same car is used in extremely cold Alaska and tropical Africa, stable warm-up characteristics can always be obtained.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the carburetor control system according to the present invention, FIG. 2 is a cross-sectional view of the actuator shown in FIG. 1, and FIG. 3 is a configuration diagram of the control circuit section shown in FIG. 1. FIG. 4 is an electrical circuit diagram of one embodiment, FIGS. 5 and 6 are duty ratio-atmosphere temperature characteristics diagrams corresponding to the choke system and fast idle system, respectively, and FIG. 7 is the result obtained by implementing this embodiment. The throttle and valve opening curves obtained are shown respectively. In the figure, 100 is the carburetor main body, 200 is the control circuit section, 300 is the battery, 400 is the actuator which is a component of the fast idle mechanism, 5
00 is a temperature sensor, 101 is a throttle valve, 103 is a choke valve, 105 is a first temperature sensing member, 106 is a first heat generating member, 204 is a first comparator, 205 is a second comparator, 207 is a first power circuit, 208 is a second power circuit, 404
405 is a second heat generating member, 405 is a second temperature sensitive member,
203 represents an oscillator, and 202 represents an attenuator.

Claims (1)

[Claims] 1. In a carburetor equipped with a throttle valve whose valve opening is controlled by a first temperature-sensitive member and a throttle valve whose first idle valve opening is controlled by a second temperature-sensitive member, A first heat-generating member that heats a first temperature-sensitive member to displace the throttle valve from a closed state to an open state, and a second heat-generating member that heats a second temperature-sensitive member to shift the throttle valve from an open state to A second heat generating member that is displaced in the closing direction, a temperature sensor that generates an output corresponding to the ambient temperature around the vaporizer, a reference voltage determined based on the output from the temperature sensor, and a triangular wave from an oscillator. a first comparator that receives a voltage signal and generates an output signal with a duty ratio corresponding to the output from the temperature sensor; a second comparator that receives a square wave voltage signal and generates an output signal with a duty ratio corresponding to the output from the temperature sensor; and a second comparator that generates an output signal with a duty ratio corresponding to the output from the temperature sensor; a first power circuit that supplies the first heat generating member; and a second power circuit that supplies the second heat generating member with power corresponding to the duty ratio output signal from the second comparator. A valve opening control device for a carburetor, comprising: