JPH0849602A - Valve controller - Google Patents

Abstract

PURPOSE:To certainly start an engine by opening the movable valve body of a carburetor after confirming that an engine speed is enough built up at an engine starting time. CONSTITUTION:A valve controller is provided with a frequency signal generating means 10, a frequency discriminating circuit 12, a reversing circuit 14, a D type flip-flop 16 and an NPN type power transistor 18. When the reference frequency fs in the frequency discriminating circuit 12 is set to, for example, 600 rpm, the transistor 18 stays under its OFF condition until an engine speed reaches 600 rpm at a starting time and a PTC element 20 develops no heat so that a choke valve 104 is closing, while a bimetallic coil 120 keeps its shrinking. Hereby, a rich air-fuel mixture GA is supplied to a cylinder during an engine warming up period. When the engine speed reaches 600 rpm, the transistor 18 is switched on, the PTC element 20 is electrified and develops heat, and this heat is transmitted to the bimetallic coil 120 which is deformed in its extending direction so as to open the choke valve 104.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve control device for controlling the position of a movable valve body inside a carburetor.

[0002]

2. Description of the Related Art Carburettors are generally used in engine fuel supply systems for motorcycles and light vehicles. The carburetor is located in the intake passage of the gasoline engine,
It is a device that atomizes gasoline, mixes it with air, and sends it to the cylinder.

FIG. 6 shows the structure of a carburetor. A Venturi tube 100a having a reduced diameter is formed in an intermediate region of a cylindrical carburetor body 100 having an air cleaner 102 attached to an upper end thereof.
A choke valve 104 and a throttle valve 106 are provided upstream and downstream of a, respectively, and a float chamber 108 is provided outside thereof. Float chamber 108
In the inside, gasoline G is stored at a constant oil level, and the nozzle 1
It communicates with the Venturi tube 100a through 10.

When the air supplied from the air cleaner 102 passes through the venturi pipe 100a, the gasoline G is atomized at the tip of the nozzle 110 due to the Venturi effect, and the atomized mixture GA of the air and gasoline GA forms the throttle valve 106.
And is preheated by the honeycomb heater 112 and then distributed to the cylinders through the intake manifold 114.

By the way, the ignition condition of the engine when it is started at a cold temperature is in the worst state. When it is cold, the engine speed does not increase even if cranking is performed by the starting motor, and the compression temperature does not increase, so that atomization or vaporization of gasoline is poor. Therefore, at the cold start, the choke valve 104
Is closed to increase the negative pressure of the Venturi pipe 100a and increase the air-fuel ratio of the air-fuel mixture GA to supply it to the cylinder.

In the illustrated carburetor, the choke valve 104
In order to perform opening / closing control of the choke valve 104, a spiral bimetal coil 120 is provided outside the carburetor main body 100 adjacent to the choke valve 104, and a movable end 120 a of the bimetal coil 120 is connected to the choke valve via a lever 122 and a link 124. It is connected to 104. During cranking immediately after turning on the ignition key, the bimetal coil 120 is contracted (in the original position), the choke valve 104 is closed, and the mixture gas GA having a high concentration is generated in the venturi pipe 100a. When the engine starts, P
A heating means (not shown) such as a TC element is energized to generate heat,
The heat is transmitted to the bimetal coil 120 via the thermally conductive stud portion 126, and is deformed or displaced in the extending direction of the bimetal coil 120 to gradually open the choke valve 104, and when the engine temperature rises. The choke valve 104 is configured to be fully opened.

[0007]

However, conventionally, at the time of cold start, the bimetal coil 120 operates (deforms) to open the choke valve 104 before the engine warms up to a sufficient number of revolutions, and the so-called fog phenomenon occurs. In many cases, the engine could not be started, such as when the

Further, many carburetor engines for light automobiles and the like do not have an ECU (engine control unit) mounted therein, and even if the engine speed rises abnormally when the accelerator is depressed too much or the engine is out of order (for example, 6000 rpm). However, it was dangerous because there was no fail-safe function to automatically stop it, and fuel consumption was uneconomical.

The present invention has been made in view of the above problems, and it is a first object of the present invention to provide a valve control device for controlling the fuel supply amount to the engine based on the engine speed. To do.

A second object of the present invention is to provide a valve control device for opening the movable valve body of the carburetor to surely start the engine after confirming that the engine speed has risen sufficiently at the time of starting. To provide.

A third object of the present invention is to provide a valve control device which automatically suppresses excessive fuel supply when the engine speed becomes too high due to overrun or engine malfunction. It is in.

[0012]

In order to achieve the above first object, the first valve control device of the present invention is a frequency signal generating means for generating a frequency signal having a frequency corresponding to the engine speed. A frequency discriminating means for discriminating whether or not the frequency of the frequency signal is higher than a set value by inputting the frequency signal from the frequency signal generating means, and a movable valve in the carburetor according to the discrimination result of the frequency discriminating means. And a means for controlling the position of the body.

In order to achieve the above-mentioned second object, a second valve control device of the present invention comprises a heat-sensitive deformable member which is connected to a movable valve element in a carburetor and deforms according to a temperature change, and the heat-sensitive deformation. Heating means for heating the member, frequency signal generating means for generating a frequency signal having a frequency corresponding to the engine speed, and inputting the frequency signal from the frequency signal generating means, the frequency of the frequency signal is A frequency discriminating means for discriminating whether or not the frequency is higher than a set frequency, and the heat-sensitive deformation according to the discriminating result of the frequency discriminating means so as to open the movable valve body when the frequency of the frequency signal exceeds the set frequency. And a control means for starting the heating of the heating means with respect to the member.

In order to achieve the above-mentioned third object, a third valve control device of the present invention comprises a heat-sensitive deformable member connected to a movable valve element in a carburetor, which deforms in response to a temperature change, and the heat-sensitive deformation. Heating means for heating the member, frequency signal generating means for generating a frequency signal having a frequency corresponding to the engine speed, and inputting the frequency signal from the frequency signal generating means, the frequency of the frequency signal is Frequency determining means for determining whether or not the frequency is higher than a set frequency, and the heat-sensitive deformation according to the determination result of the frequency determining means for closing the movable valve body when the frequency of the frequency signal exceeds the set frequency. And a control means for stopping the heating of the heating means to the member.

[0015]

In the first valve control device, the frequency signal generating means and the frequency determining means determine (monitor) whether or not the engine speed is higher than the set value, and the inside of the carburetor is determined according to the result of the determination (monitoring). Control the position of the movable valve body.
In this way, by controlling the position of the movable valve element in the carburetor based on the engine speed, it is possible to supply fuel in proportion to the engine speed.

In the second valve control device, the movable valve element (for example, a choke valve) in the carburetor is closed until the engine speed reaches the set value, and after confirming (detecting) the time when the set value is reached, Since the movable valve body (choke valve) is opened via the heat sensitive member by starting the heating of the heating means, the engine can be reliably started without causing the fog phenomenon even at low temperatures.

In the third valve control device, the movable valve element (for example, a choke valve) in the carburetor is opened until the engine speed reaches the set value, and after confirming (detecting) the time when the set value is reached, Since the movable valve body (choke valve) is closed via the heat sensitive member by stopping the heating of the heating means, it suppresses the excessive supply of fuel to the engine during high-speed operation or during abnormalities, thus ensuring safety and economy. Can be improved.

[0018]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 is a block diagram showing a circuit configuration of a valve controller according to an embodiment of the present invention. This valve control device is applicable to the carburetor shown in FIG. 6, and includes a frequency signal generating means 10, a frequency discriminating circuit 12, an inverting circuit 14, a D-type flip-flop 16, and an NPN-type power transistor 18. Have

The emitter terminal of the NPN type power transistor 18 is grounded, and the collector terminal is connected via the PTC element 20 to the power supply voltage terminal Vcc of 12V, for example. The PTC element 20 is a heating means for heating the bimetal coil 120, and is thermally connected to the bimetal coil 120 via an appropriate heat conductive member 22 and the stud member 126, which are simply shown by chain lines. There is.

The frequency signal generating means 10 is, for example, an engine speed sensor constructed by attaching an optical sensor, a semiconductor Hall effect type sensor, a power generation type sensor or the like to a crank, and corresponds to the engine speed (identical). Or generate a pulse ES having a frequency f (proportional).

The frequency discriminating circuit 12 receives the pulse signal ES from the frequency signal generating means 10, and the frequency f of the pulse signal ES has a set value fs (for example, 600 rpm).
A circuit for determining whether or not it is higher, and when f ≦ fs, an output voltage DS of a pulse signal having the same frequency as the pulse signal ES but a different phase is generated as shown in FIG. , F> fs, the H-level output voltage DS is constantly generated as shown in FIG.

Here, FIG. 2 shows a specific configuration example of the frequency discriminating circuit 12. The frequency discriminating circuit 12 includes a general-purpose linear IC 12a having a built-in flip-flop and a resistor R
A, RL, capacitors C1 and C2, and a PNP transistor Tr are externally connected as shown. The input terminal 12b is connected to the trigger input terminal (TRIGGER) of the linear IC 12a, and the transistor T
It is connected to the base terminal of r.

FIG. 3 shows the operation of the frequency discrimination circuit 12 in an easy-to-understand manner. As shown in FIG. 3, every time the input pulse signal ES (INPUT) falls from the H level to the L level, the transistor Tr is turned on and the capacitor C1 is discharged. When the period T of the input pulse signal ES is shorter than the time constant Ts determined by the capacitor C1 and the resistor RA, that is, when the frequency f of the input pulse signal ES is higher than fs (1 / Ts), the voltage of the capacitor C1 ( Before the DISCHARGE) reaches a predetermined threshold value VH, the capacitor C1 is discharged and the flip-flop inside the IC is set, and the output voltage (OUTPUT) constantly maintains the H level. However, when the cycle T of the input pulse signal ES becomes longer than the time constant TS, that is, the frequency f of the input pulse signal ES becomes fs (1 /
When it becomes lower than Ts), the charging voltage (DISCHARGE) of the capacitor C1 reaches the threshold value VH, the flip-flop inside the IC is reset, and the output voltage (OUTP
UT) becomes L bell. By appropriately selecting the capacitance of the capacitor C1 or the resistance value of the resistor RA, the desired time constant TS or the reference frequency fs (1 / Ts) can be set.

In this way, the frequency signal generating means 10
Depending on whether or not the frequency f of the pulse signal ES from is higher than a set value fs (for example, 600 rpm), the output voltage DS of the frequency discriminating circuit 12 is in a state (f≤fs) as shown in FIG. Case) or the state shown in FIG. 4B (when f <fs).

Referring again to FIG. 1, the D-type flip-flop 16 constitutes a latch circuit for reading the discrimination result of the frequency discrimination circuit 12, and the pulse signal ES from the inverting circuit 14 inputted to the clock input terminal (CLK). _- (a signal obtained by inverting the pulse signal ES) and the strobe signal, the strobe signal ES _- captures the logic level of the output voltage DS from the frequency discrimination circuit 12 is input to the data input terminal (D) at the rising, this takes An output voltage having a different logic level is output from the non-inverting output terminal (Q).

However, when the frequency f of the pulse signal ES from the frequency signal generating means 10 is lower than the set value fs (f≤fs), as shown in FIG. An L-level output voltage is obtained at the non-inverting output terminal (Q). At this time, the transistor 18 is in the off state, and the PTC element 20 is not energized and does not generate heat. Further, when the frequency f of the pulse signal ES is higher than the set value fs (f> fs), as shown in FIG. 4B, the non-inversion output terminal (Q) of the D-type flip-flop 16 is at H level. A level output voltage is obtained. At this time, the transistor 1
8, the PTC element 20 is energized to generate heat.

When the valve control device as described above is applied to the carburetor shown in FIG. 5, the reference frequency fs is, for example, 600r.
If set to pm, the engine speed will be 600r at startup.
Since the PTC element 20 does not generate heat until reaching pm, the bimetal coil 120 remains contracted (in the original position) and the choke valve 104 is closed. This allows the Venturi tube 10 to warm up while the engine is warming up.
Air-fuel mixture GA richer than 0a is supplied to the cylinder, and the engine speed (idling speed) rises smoothly. Then, when the engine speed reaches 600 rpm, the PTC element 20 is energized to generate heat, and the heat is transmitted to the bimetal coil 120, and the bimetal coil 12
When the temperature of the engine becomes sufficiently high, the choke valve 104 is fully opened when it deforms in the direction in which 0 extends.

As described above, in the present embodiment, the choke valve is closed until the engine speed reaches the set value (600 rpm), and the time when the set value (600 rpm) is reached is confirmed (detected) before the PTC element. 20 energization heat generation (heating)
Since the bimetal coil 120 is heated to open the choke valve 104, the engine can be reliably started without causing a fog phenomenon even at low temperature.

The frequency discriminating circuit according to the present invention can be used not only for detecting the engine speed at the time of starting as in the above embodiment, but also for detecting the engine speed at the time of abnormality.

For example, it is possible to configure a valve control device having a circuit configuration as shown in FIG. 5 for a carburetor type engine such as a light vehicle without an ECU (engine control unit). In the figure, the same parts as those in FIG. 1 are designated by the same reference numerals. In this embodiment, in addition to the structure of the first embodiment, a frequency discriminating circuit 30, an inverting circuit 32 and a D-type flip-flop 34 are provided.

The frequency discrimination circuit 30 is the frequency discrimination circuit 12
Although the circuit configuration is the same as the above, its reference frequency fs' is set to, for example, 6000 rpm. On the output side of the D-type flip-flop 34, the inverting output terminal (Q ₋ ) is connected to the base terminal of the NPN transistor 18.

[0033] According to such a configuration, while the engine speed is less than 6000 rpm, the output voltage DS 'is L level of the frequency discriminating circuit 30, the inverted output terminal of the D-type flip-flop 34 (Q _-) output voltage of H level, N
The ON / OFF state of the PN transistor 18 depends on the voltage level state of the non-inverting output terminal (Q) of the D-type flip-flop 34, that is, the voltage level state of the output voltage DS of the frequency discrimination circuit 12. That is, as described above, N
The engine speed of the PN transistor 18 is 600 rp
When it is m or less, it is in an off state, and when it is 600 rpm or more, it is in an on state.

However, the engine speed rises abnormally due to excessive depression of the accelerator, engine malfunction, etc.
When it exceeds 0 rpm, the output voltage D of the frequency discrimination circuit 30
S ′ becomes H level, and the voltage level state of the inverting output terminal (Q ₋ ) of the D flip-flop 16 becomes L level. Then, the NPN transistor 18 changes from the ON state to the OFF state, the PTC element 20 does not generate heat, the bimetal coil 120 is displaced (returned) to the original position, and the choke valve 104 is closed. As a result, the amount of air or fuel supplied to the engine is reduced, and the engine speed is reduced.

As described above, according to the present embodiment, it is possible to automatically suppress an abnormally high engine speed by a simple valve control mechanism without using an ECU, thereby improving safety and fuel efficiency. You can improve.

In the fail-safe function described above,
Although the choke valve is configured to be closed when an abnormality occurs, it is also possible to configure another movable valve such as the throttle valve 106 to be closed.

The heating means in the present invention is not limited to the PTC element 20, and other resistance heating element or other heating element may be used. It is also possible to use a high power relay circuit to energize the heating means. The heat-sensitive deformable member may have any structure and shape.

[0038]

As described above, according to the first valve control device of the present invention, the position of the movable valve element in the carburetor is controlled based on the engine speed, so that the engine condition can be met. Fuel can be supplied.

According to the second valve control device of the present invention, the movable valve element (eg, choke valve) in the carburetor is closed until the engine speed reaches the set value, and the time when the set value is reached is detected. After that, the heating of the heating means is started and the movable valve body (choke valve) is opened via the heat sensitive member, so that the engine can be reliably started without causing the fog phenomenon even at low temperatures. it can.

According to the third valve control device of the present invention, the movable valve element in the carburetor is kept open until the engine speed reaches the set value, and the heating means is detected when the set value is reached. Since the heating is stopped and the movable valve body is closed via the heat sensitive member, it is possible to suppress the excessive supply of fuel to the engine during high speed operation or during an abnormality, and improve safety and economy.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of a valve control device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a specific configuration example of a frequency discriminating circuit in the embodiment.

FIG. 3 is a signal waveform diagram showing waveforms of signals of respective parts for easily explaining the operation of the frequency discrimination circuit in the example.

FIG. 4 is a timing chart showing the operation of each part of the valve control device in the embodiment.

FIG. 5 is a block diagram showing a circuit configuration of a valve control device according to a second embodiment.

FIG. 6 is a cross-sectional view showing a configuration of a carburetor.

[Explanation of symbols]

 10 frequency signal generating means 12,30 frequency discriminating circuit 14,32 inverting circuit 16,34 D-type flip-flop 18 NPN type power transistor 20 PTC element 100 carburetor body 104 choke valve 106 throttle valve 120 bimetal coil

Claims (3)

[Claims] 1. A frequency signal generating means for generating a frequency signal having a frequency corresponding to an engine speed, and the frequency signal input from the frequency signal generating means,
A frequency discriminating means for discriminating whether or not the frequency of the frequency signal is higher than a set value, and means for controlling the position of the movable valve element in the carburetor according to the discrimination result of the frequency discriminating means. Valve control device. 2. A heat-sensitive deformable member which is connected to a movable valve element in a carburetor and deforms in response to a temperature change, a heating means for heating the heat-sensitive deformable member, and a frequency corresponding to an engine speed. Frequency signal generating means for generating a frequency signal, and inputting the frequency signal from the frequency signal generating means,
Frequency determining means for determining whether the frequency of the frequency signal is higher than a set value, and the frequency determining means for opening the movable valve body when the frequency of the frequency signal exceeds the set value. And a control unit that starts heating of the heating unit with respect to the heat-sensitive deformable member according to a result. 3. A heat-sensitive deformable member which is connected to a movable valve element in a carburetor and deforms in response to a temperature change, a heating means for heating the heat-sensitive deformable member, and a frequency corresponding to an engine speed. Frequency signal generating means for generating a frequency signal, and inputting the frequency signal from the frequency signal generating means,
A frequency discriminating means for discriminating whether or not the frequency of the frequency signal is higher than a set value, and discriminating by the frequency discriminating means so as to close the movable valve body when the frequency of the frequency signal exceeds the set value. And a control unit that stops heating of the heating unit with respect to the heat-sensitive deformable member according to the result.