JPS6312870A - Air bleed controller for carburetor - Google Patents

Abstract

PURPOSE:To enable accurate setting of a motor to a referential condition without requiring a referential position detecting sensor, in a system having a step motor for controlling the opening of an air bleed control valve, by providing a plurality of output means and means for setting the number of referential rotation steps. CONSTITUTION:A flow control means 2 the opening of which is controlled by a step motor 3 which is controlled by a rotation steps control means 6 is arranged in a path 1c communicated to a Venturi 1b. First and second output means 7a, 7b which output signals for rotating the motor 3 in the direction for minimizing the opening of the flow control means 2 when a complete combustion condition is detected by a complete combustion detecting means 8 and at the start of engine are provided. Furthermore, means for setting the data value stored in a memory means 4 to a referential rotation steps from the start of engine until the setting control of the rotation steps is started by the rotation steps control means 6 is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an air bleed control device for a carburetor. , Improvement of an air bleed control device for a carburetor that controls the amount of air bleed flowing from the atmosphere into the main fuel supply passage or the slow fuel supply passage communicating with the intake passage of the carburetor according to the operating state of the engine. Regarding.

[Prior art]

As shown in Japanese Patent Application Laid-Open No. 57-26240, a conventional device of this kind is designed to reduce the amount of air bleed flowing from the atmosphere into the main system fuel supply passage and the slow system fuel supply passage that communicate with the intake passage of the carburetor. An air bleed amount control valve that controls the opening degree according to the opening degree, a step motor that sets and controls the opening degree of this control valve according to the number of rotation steps from a reference state, and an electric control device that controls the rotation of this step motor. and a position sensor disposed within a housing housing the air bleed amount control valve and the step motor to detect a reference state of the step motor. When the engine is started, the electric control device works with the position sensor to set the step motor to the reference state, and at the same time monitors the number of rotation steps from the reference state of the step motor. The control device initializes the reference value with a count value that increases (or decreases) in accordance with By outputting a rotation drive signal to the step motor according to the difference from the monitor count value, the number of rotation steps from the reference state of the motor is set to the target rotation step number, and the air bleed amount control valve is controlled. The air bleed amount is controlled according to the opening degree of the air bleed.

[Problem that the invention seeks to solve]

However, in the above-mentioned conventional device, in order to initialize the count value for the monitor, a position sensor for detecting the reference state of the step motor is disposed inside the housing containing the air bleed amount control valve and the step motor. This arrangement complicates the structure of the air bleed control device, increases the size of the device, and increases the manufacturing cost of the device. In addition, if this position sensor fails, it becomes impossible to detect the reference state of the step motor, so the count value for the monitor is not properly initialized (as a result, the count value is Since it is no longer possible to monitor the number of rotational steps from the reference state set by the step motor, the number of rotational steps from the reference state of the step motor is no longer set to the target number of rotational steps calculated by the electric control device, and the amount of air bleed is There has been a problem in that the air bleed amount set by the opening degree of the control valve, that is, the air-fuel ratio of the air-fuel mixture supplied from the carburetor to the engine, becomes incorrect.

The present invention has been devised in view of the above problems, and its purpose is to accurately set the step motor to the reference state immediately after starting the engine without using a position sensor to detect the reference state of the step motor. The present invention aims to provide an air bleed control device for a carburetor that solves the above-mentioned problems by making it possible to set the number of rotational steps from the reference state of the step motor at all times. be.

[Means for solving problems]

In order to solve such problems and achieve the above objectives, this book 1
The structural feature of the invention is as shown in FIG.
The amount of air bleed that flows from the atmosphere into the venturi 1b or the downstream part thereof through the communication passage 1c that is interposed in the communication passage IC that communicates the venturi 1b provided in the intake passage 1a or its downstream part with the atmosphere. A flow rate control means 2 that controls according to the opening degree, and a flow rate control means 2 that is connected to the flow rate control means 2 and that responds to an increase in the number of rotation steps in one direction based on the time when the opening degree of the flow rate control means 2 is the minimum. a step motor 3 for increasing the opening degree of the flow rate control means 2; and a storage means 4 for storing data representing the current number of rotational steps in the one direction that is actually set by the step motor 3.
and target rotation step number determining means 5 for determining the target rotation step number in the one direction to be set by the step motor 3 based on the operating state of the engine after complete explosion;
A rotation drive signal corresponding to the difference between the determined target number of rotation steps and the current number of rotation steps represented by the data stored in the storage means 4 is output to the step motor 3 to cause the step motor 3 to move in the one direction. A carburetor 1 comprising a rotation step number control means 6 for controlling and setting the number of rotation steps to the determined target number of rotation steps and updating the stored data value of the storage means 4 to the determined target number of rotation steps.
In this air bleed control device, a rotational drive signal is sent to the step motor to minimize the opening degree of the flow rate control means 2 by rotating the step motor 3 in a direction opposite to the one direction when starting the engine. The first output to 3
an output means 7a; a complete explosion detection means 8 for detecting a complete explosion state of the engine; and when the complete explosion state is detected, the stepping motor 3 is rotated in the opposite direction to minimize the opening degree of the flow rate control means 2. a second output means 7b for outputting a rotational drive signal to the step motor 3 for the purpose of controlling the number of rotational steps; A reference rotation step number setting means 9 is provided for setting the stored data value of No. 4 as the reference rotation step number.

[Action of the invention]

In the present invention configured as described above, when the engine is started, the first output hand 117a outputs a rotational drive signal for minimizing the opening degree of the flow rate control means 2 to the step motor 3. 3 is driven and controlled to a reference state corresponding to the minimum opening degree of the flow rate control means 2. Through this drive control, the opening degree of the flow rate control means 2 is brought to the minimum or close to the minimum state, and the amount of air bleed supplied to the venturi 1b of the intake passage 1a of the carburetor 1 or the downstream part thereof is reduced. 1, the mixture supplied to the engine becomes richer, and the engine is quickly started and reaches a complete explosion state.

This complete explosion is detected by the complete explosion detection means 8, and when this complete explosion is detected, the second output means 7b controls the step motor 3 to the minimum opening degree of the flow rate control means 2, as in the case of the first output means 7a. Drive control to the corresponding reference state. These first and second
As a result of the drive control by the output means 7a and 7b, the battery voltage increases (decreases) as the engine starts, for example, when the viscosity of the engine oil is high in cold weather, that is, when the load on the starter for starting the engine is large. When the engine is started, a large drive current flows from the battery to the starter at the time of starting, and the battery voltage at the time of starting drops significantly, so that the step motor 3 is reliably driven to rotate to the reference state when the engine is started. Even if there is no motor 3,
When the battery voltage returns to its normal value due to the complete explosion of the engine, it is rotated again to return to the reference state, so after the complete explosion of the engine, the step motor 3 corresponds to the minimum opening of the flow rate control means 2. This means that the setting control will be reliably set to the reference state that has been set.

On the other hand, the reference rotation step number setting means 9 sets the stored data value of the storage means 4 to the reference rotation step number from the time the engine is started until the rotation step number setting control by the rotation step number control means 6 starts. Therefore, at the time when the rotation step number control means 6 starts controlling the setting of the rotation step number, the current rotation step number represented by the stored data in the storage means 4 is initially set to the reference rotation step number. . From this state, the rotation step number control means 6 controls the rotation step number according to the difference between the target rotation step number determined by the target rotation step number determination means 5 and the current rotation step number represented by the data stored in the storage means 4. The rotation drive signal is output to the step motor 3, and the step motor 3
Since the number of rotation steps is controlled and the stored data value of the storage means 4 is updated to the target number of rotation steps,
The number of rotational steps of the step motor 3 is accurately monitored by the stored data value of the storage means 4, that is, the current number of rotational steps, which is sequentially updated from the reference number of rotational steps, so that the number of rotational steps of the step motor 3 accurately matches the target number of rotational steps. will be controlled by.

Since the opening degree of the flow rate control means 2 is controlled according to the precisely controlled number of rotational steps of the step motor 3, the venturi 1b provided in the intake passage 1a of the carburetor 1
Alternatively, the amount of air bleed supplied from the atmosphere to the downstream portion thereof via the communication path IC can be accurately controlled.

〔Effect of the invention〕

As can be understood from the above description of the action, according to the present invention,
Even without using a position sensor to detect the reference state of the step motor 3 as in the conventional device described above, the step motor 3 can be reliably set and controlled to the reference state immediately after the engine is started by simple, purely electrical processing. Furthermore, when controlling the amount of air bleed after the engine has completely exploded, the number of rotational steps of the step motor 3 is reliably monitored and the control of the amount of air bleed does not become inaccurate, so the position sensor is no longer required. , compared to the above conventional air bleed control device,
The structure of the device becomes simpler and at the same time it becomes possible to downsize the device. As a result, the manufacturing cost of the air bleed control device can be reduced compared to the conventional method.

Further, according to the present invention, as described above, the step motor 3
As a result, as in the conventional device described above, when the position sensor fails, the amount of air bleed, that is, the air-fuel ratio of the mixture supplied from the carburetor to the engine, becomes incorrect. This reduces harmful exhaust gas components emitted from the engine, improves drivability, and improves fuel efficiency.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows an example in which the air bleed control device according to the present invention is used in the main fuel system of the main and slow fuel systems of the carburetor 20. It shows.

The carburetor 20 has an intake body 21, and the intake body 21 is connected between an intake pipe (not shown) extending from the air cleaner and an intake pipe (not shown) extending from the engine. Allows tracheal communication. A fixed venturi 23 is assembled on the inner periphery of the intake cylinder 21 upstream of the throttle valve 22, and a float chamber 2 is installed on the outer periphery of the intake cylinder 21.
4 are provided. A fuel passage 21a is formed in the peripheral wall of the intake body 21 and the base of the fixed venturi 23,
The road 21a has a main jet 2 fitted at one end.
5 to the float chamber 24, and communicates to the inside of the intake cylinder 21 via a main nozzle 26 fitted to the other end. In the middle of this fuel passage 21a, an intake cylinder 21
An air bleed passage 21b formed in the peripheral wall of the fuel passage 21 and the base of the fixed venturi 23 is open, so that the air flow supplied through the passage 21b flows out into the fuel passage 21a. In addition, the throttle valve 22 of the intake cylinder 21
A slow boat 21c and an idle boat 21d that are open inside the intake shell 21 are provided at positions facing the intake shell 21, and slow system fuel is sucked into the intake shell 21 through these boats 21C921d. ing.

Note that special numbers 27 and 28 indicate a slow boat plug and an idle adjustment screw, respectively.

The air bleed control device has a control valve device 30 that controls the flow rate of air flowing into the air bleed passage 21b of the carburetor 20 from the atmosphere.
and a cup-shaped upper case 32 fitted into the same case 31. The lower case 31 houses a step motor 33 and a plunger 34. step motor 33
is a stator 33 fixed to the inner peripheral surface of the lower case 32.
a, and a cylinder disposed on the inner periphery of the stator 33a coaxially with the stator 33a, and assembled into the lower case 31 via a bearing 35 so as to be rotatable and immovable in the vertical direction in FIG. It consists of a rotor 33b of a shape. The plunger 34 has a male thread formed on its base 34a that is engaged with a female thread formed on the inner circumferential surface of the rotor 33b, and its tip 34b cannot rotate inside the lower case 31 but is movable in the vertical direction in FIG. The distal end portion 34b penetrates the upper wall 31a of the lower case 31 and enters the upper case 32.

The upper case 31b accommodates a needle-shaped valve body 36 disposed coaxially with the plunger 34.

The valve body 36 is received by the plunger 34 via a retainer 37 fixed to its lower end, and is pushed downward in FIG. Forced. The tip of the valve body 36 is connected to the cylindrical body 32 provided above the upper case 32.
a, and the annular area between the annular valve seat portion 32b provided on the intermediate inner peripheral surface of the cylindrical body 32a and the outer peripheral surface of the distal end of the valve body 36 is as shown in FIG. 2 of the valve body 36. It becomes smaller (or larger) as it moves in the (or downward) direction. The upstream part of the cylinder 32a is connected to the atmosphere through a hose 39a connected to an input boat 32c, and the downstream part of the cylinder 32a is connected to the air bleed of the carburetor 20 by a hose 39b connected to an output port 32d. Passage 21c
is connected to.

The air bleed control device also includes an electric control device 40 that controls the rotation of the step motor 33 of the control valve device 30. The electric control device 40 includes an engine rotation speed sensor 41, a water temperature sensor 42, an oxygen concentration sensor 43, and various sensors 41, 42 for detecting the operating state of the engine.
．． A microcomputer 44 that controls the number of rotation steps of the step motor 33 according to each detection signal from the motor 43, and a battery that supplies power to the microcomputer 44 and a starter (not shown) for starting the engine via an ignition switch 45. 46.

The engine rotation speed sensor 41 detects the rotation of the camshaft in the distributor attached to the engine, forms an engine rotation speed signal representing the engine rotation speed Ne based on the detected rotation angle, and transmits the rotation speed signal to the microcomputer. 4
Output to 4. The water temperature sensor 42 detects the coolant temperature Tw in the engine cooling system and outputs a water temperature signal representing the detected coolant temperature Tw to the microcomputer 44.

The oxygen concentration sensor 43 detects the oxygen concentration in the exhaust gas discharged from the engine, and becomes high level when the air-fuel ratio of the air-fuel mixture at that time is higher than the stoichiometric air-fuel ratio (rich), and when the air-fuel ratio is higher than the stoichiometric air-fuel ratio. An oxygen concentration detection signal that becomes low level when the air-fuel ratio is lower (lean) than the air-fuel ratio is output to the microcomputer 44.

The microcomputer 44 has a read-only memory (hereinafter referred to as R).
(hereinafter referred to as OM) 44a, central processing unit (hereinafter referred to as CPU) 44b, writable memory (hereinafter referred to as RAM) 4
4c, input/output interface (hereinafter referred to as I10) 4
4d, and these ROM44a, CPU44b, RA
A bus 44 that commonly connects M44c and l1044d.
Consists of e. The ROM 44a stores a program corresponding to the flowchart shown in FIG. The CPU 44b executes the program in response to the closing of the ignition switch 45. The RAM 44c temporarily stores data necessary for executing the program. l1044d is
Signals from the engine speed sensor 41, water temperature sensor 42, and oxygen concentration sensor 43 are input, and the input signals are converted into a format that can be processed by the program. Further, a drive circuit 47 is connected to the l1044d, and the circuit 47 is controlled by the microcomputer 44 to output a drive pulse train signal for driving the step motor 33. A battery 46 is also connected to this drive circuit 47 via the ignition switch 45, and power from the battery 46 is supplied to the circuit 47 when the ignition switch 45 is closed.

The operation of the embodiment configured as described above will be explained below with reference to the flowchart of FIG.

First, to explain the general operation, when the ignition switch 45 is closed and the engine is started and controlled by the starter, the CPU 44b starts executing the program in step 50, and executes the program consisting of steps 60 to 68. The step motor 33 is set to the reference state by setting the step motor 33 to the reference state, and the current rotational step number data 5NOW is set to the reference value "0". After the processing of the "initial control routine", steps 70 to While repeatedly executing the process of "air bleed control routine" consisting of 79 and updating the current rotation step number data 5NOW,
The number of rotation steps of the step motor 33, that is, the amount of air bleed flowing into the carburetor 20 from the atmosphere via the control valve device 30 is controlled according to the operating state of the engine.

Note that the reference state of the step motor 33 means that the rotor 33
The left rotation of b causes the plunger 34 to push up the retainer 37 to the highest point, and the valve body 36 is placed in the fully closed state of the control valve device 30 seated on the valve seat 32b, that is, the upstream and downstream portions of the cylinder body 32a. This means a state in which communication with the air is prohibited and air is not allowed to flow into the fuel passage 21a of the carburetor 20 from the atmosphere through the air bleed passage 21b. In this embodiment, this state of the step motor 33 is expressed as the number of rotational steps "0". In addition, by clockwise rotation of the step motor 33, the plunger 34 and the retainer 37
moves downward from the above state in FIG. 2 and flows from the atmosphere into the annular area between the valve body 36 and the valve seat 32b, that is, into the fuel passage 21a of the carburetor 20 via the air bleed passage 21b. In a state where the amount of air bleed increases, the number of rotational steps of the step motor 33 is expressed as a value that increases by "1" from "0", and the number of rotation steps of the step motor 33 is
When the retainer 37 is at the lowest point and the annular area and air bleed amount are maximum, the number of rotational steps of the step motor 33 is expressed as rlooJ.

Next, the processing operations in the "initial control routine" consisting of steps 60 to 68 will be described in detail. In this "initial control routine", the CPU 44b sets the rotation step number data 5NOW to rl in step 60.
Various data stored in the RAM 44c are initialized, such as setting to 10J.

After the initial setting in step 60, the CPU 44b performs step 6.
1, a control signal for rotating the rotor 33b by one step in the left direction, that is, in the closing direction of the control valve device 30, is sent to the I/Q.
44d to a drive circuit 47, and the circuit 47 outputs a drive signal to the step motor 33 to rotate the rotor 33b one step in the left direction in response to this control signal.

After the processing in step 61, the CPU 44b updates the data 5NOW to "109" by subtracting "1" from the current rotation step number data 5HOW set in rl 10J by the above initial setting in step 62. At step 63, based on the current rotational step number data 5HOW set in the rlO9J, it is determined that rNOJ, that is, the current rotational step number data 5HOW, is not "0", and the program returns to step 61. And the CPU
44b again executes the same steps 61 and 62 as described above to control the rotation of the rotor 33b one step leftward, and subtracts "1" from the current rotational step number data 5NOW. In this case, the current rotation step number data 5
Since NOW is updated to r108J, the CPU 44b determines that rNOJ, that is, the current rotation step number data 5HOW (-r108J) is not "0" in step 6-3, and returns the program to step 61 again, and from then on, the current rotation The cyclic processing of steps 61 to 63 is continued until the step number data 5NOW becomes "0". When the current rotation step number data 5NOW becomes "0" through this circulation process,
The CPU 44b determines rYEsJ in step 63 and advances the program to step 64.

Through the circulation process of steps 61 to 63, the rotor 33b is rotated leftward one step at a time, and the plunger 34 moves the retainer 37 upward in FIG. The annular area between the valve seat portion 32b and the valve seat portion 32b is reduced. In this case, first rl 10J
The current rotation step number data 5NOW set to rOJ
The above-mentioned circulation process is executed until the step motor 33 is rotated. Regardless of the value of the step number from "0" to rloOJ, the step motor 33 is set to the reference state, and as a result,
The control valve device 30 is set to a fully closed state. Note that during the circulation process, if the step motor 33 reaches the reference state before the current rotation step number data 5NOW becomes "0", the drive signal from the drive circuit 47 is changed to the same motor by the process of step 61. 33, but in this state, since the valve body 36 is seated on the valve seat portion 32b, the plunger 3
4 is prohibited from moving upward in FIG. 2, and the rotor 33b
does not rotate.

In addition, the engine is started in a state where the viscosity of the engine oil is high in cold and cold conditions, that is, in a state where the load on the starter for starting the engine is large, and during the circulation process consisting of steps 61 to 63, the engine oil is supplied to the drive circuit 47. The battery voltage decreases as shown in FIG. 4, and the thrust obtained by this decreased voltage is applied to the rotor 33b as shown in FIG.
When the step motor 33 becomes so small that it cannot be reliably driven, that is, when the step motor 33 becomes inoperable, the step motor 33 cannot be reliably set to the reference state by the circulation process. However, even in this case, the rotor 33b is rotationally driven at least in the left direction, that is, in the closing direction of the control valve device 30, and the step motor 33 is set to a state close to the reference state.

By controlling the step motor 33, the annular area between the valve body 36 and the valve seat portion 32b becomes zero or a small value, and the hose 39a, the cylinder body 32a of the control valve device 30, the hose 39b, and the vaporizer 20 are removed from the atmosphere. The amount of air bleed flowing into the fuel passage 21a via the air bleed passage 21b is reduced. As a result, the amount of fuel sucked out from the float chamber 24 into the intake shell 20 through the main jet 25, the fuel passage 21a, and the main nozzle 26 increases, and the amount of fuel sucked out into the intake shell 20 increases.
Since the air-fuel ratio of the air-fuel mixture mixed with air and supplied to the engine becomes rich at zero, the engine is in a state where it is easy to start, so the engine is started smoothly by the starter.

After the process in step 63, the CPU 44b executes step 64.
An engine rotation speed signal is taken in from the engine rotation speed sensor 41 via l1044d, and it is determined whether or not the engine rotation speed Ne represented by the signal is greater than 600 revolutions per minute. This 600 revolutions per minute is the engine revolution number that the engine reaches when it is fully detonated, and if the engine is not yet in a complete explosion state and the engine revolution number Ne is less than 600 revolutions per minute, the CPU 44b performs step 64. “NO
J is determined, and the determination process of step 64 continues to be repeatedly executed. In addition, if the engine is already in a complete explosion state at the time of "YESJ" determination in step 63 above, or if the engine becomes a complete explosion state during the repeated process of step 64, the engine rotational speed Ne at that time is 600 revolutions per minute. If it is larger, the CPU 44 b sends rYEs in step 64.
J is determined, and in step 65, the current rotation step number data 5NOW is determined as in the above initial setting (step 60).
set rl 10J and run the program at step 66.
Proceed to the circular processing routine consisting of ~68.

In this circulation processing routine, the CPU 44b performs control to set the step motor 33 to the reference state by rotating the rotor 33b in the left direction one step at a time through the processing in step 66 in the same manner as in the circulation processing routine in steps 61 to 63 above. Then, through the processing in step 67, the current rotational step number data 5NOW is subtracted by "1" and set to "0". As a result, if the step motor 33 is not yet in the standard state and is in a state where it can rotate to the left, the rotor 33b is rotated to the left again by the processing in steps 61 to 63.
The rotation is controlled by 1OJ steps, and the step motor 33 is set to the reference state. Note that rYEs in step 68
After the determination of J, the current rotation step number data 5NOW is set to "0" by the processing of steps 67 and 68.

As a result, the engine is started in cold weather, and as described above, the step motor 33 is not set to the reference state by the circulation process consisting of steps 61 to 63 (even after the engine complete combustion is determined in step 64). , the battery voltage has returned to its normal value as shown in Fig. 4, and the thrust due to this restored voltage has become a sufficiently high value to rotate the rotor 33b, as shown in Fig. 5. , the rotor 33b rotates in the left direction, that is, in the closing direction of the control valve device 30, by the required number of steps to ensure that the step motor 33 is set to the reference state.As a result, the control valve device 30 is reliably set to the fully closed state. Settings controlled.

Next, the "air bleed control routine" consisting of steps 70 to 79 will be explained.
After determining YESJ, the CPU 44b takes in the water temperature signal from the water temperature sensor 42 via the 11044d in step 70, and determines whether the cooling water temperature Tw represented by the signal is higher than 20 degrees Celsius. In this determination, if the engine has not yet warmed up and the detected coolant temperature Tw is 20 degrees Celsius or lower, the CPU 44b determines rNOJ in step 70 and repeatedly executes the size/window processing in step 70. continue. Also, rYEs in step 68 above
At the time of determination J, the engine has already warmed up and the detected coolant temperature Tw is higher than 20 degrees Celsius, or the engine has warmed up during the repeated processing of step 70 and the detected coolant temperature Tw is higher than 20 degrees Celsius (if so, the CPU 44b is determined to be rYEsJ at step 70, and the program is executed at step 7.
Proceed to 1.

At step 71, the CPU 44b performs the step 70 described above.
The water temperature signal is read from the water temperature sensor 42 in the same manner as in the process described above, and it is determined whether or not the cooling water temperature Tw represented by the signal is less than 60 degrees Celsius.

In this case, if the engine has just been started and the cooling water temperature Tw is less than 60 degrees Celsius, the CPU 44
b is determined to be rYEsJ in step 71, and step 7
In step 2, based on the water temperature signal taken in by the processing in step 71, a target rotation step number 5GET corresponding to the cooling water temperature Tw represented by the signal is calculated. This target rotation step number 5 GET, even if the cooling water temperature Tw changes,
The control valve device 3 is controlled from the atmosphere so that the air-fuel ratio of the air-fuel mixture supplied to the engine from the carburetor 20 is always maintained at an appropriate value.
0 represents the number of rotation steps from the reference state of the step motor 33 for controlling the amount of air bleed flowing into the fuel passage 21a of the carburetor 20 through the reference state.

After calculating the target rotation step number 5GET in step 72, the CPU 44b calculates the current rotation step number data 5NO from this target rotation step number 5GET in step 73.
The number of rotational steps of the step motor 33 represented by W is subtracted from the reference state, and the subtraction result is 5GET-3NO.
It is determined whether W is greater than "0". In this case, the target rotational step number 5GET can take a value between "0" and r100J corresponding to the range of the movable rotational step number of the step motor 33, and the current rotational step number data 5NOW is the same as the step 60 described above. Since it is set to "0" by the processing of the "initial control routine" consisting of steps 68 to 68, if the calculated target rotation step number 5GET is positive, the subtraction result 5GET-3NOW is positive, and C
The PU 44b determines rYEsJ in step 73, and in step 74 outputs a control signal for rotating the rotor 33b one step in the right direction to the drive circuit 47 via 11044d. The drive circuit 47 outputs a drive signal to the step motor 33 to rotate the rotor 33b one step in the right direction, and the rotor 33b rotates one step in the right direction. After the process of step 74, the CPU 44b
In step 75, 1 is added to the current rotational step number data 5NOW, which is set to 0 as described above, to update the same data 5NOW to 1, and the current rotational step number data is While making 5NOW match the number of rotational steps from the reference state of the step motor 33,
Return the program to step 73.

Now, the calculated target rotation step number 5GET is “1”.
”, the new subtraction result 5GET-3NOW in step 73 becomes rOJ, so the CPU 44b
The determination at step 73 is "NO" and the program proceeds to step 76. Further, if the calculated target rotation step number 5GET is larger than "1", the new subtraction result 5GET-3NOW obtained by the processing in step 73 is positive, so the CPU 44b executes rY in step 73.
EsJ is determined, and the same process as above in steps 74 and 75 rotates the rotor 33b one step in the right direction, and sets the current rotational step number data 5NOW to match the number of rotational steps from the reference state of the step motor 33. In order to do so, "1" is added to the same data 5NOW, and the program returns to step 73. From then on, as mentioned above,
Subtraction result 5GET-3NOW by processing in step 73
The circular process consisting of steps 73 to 75 continues to be executed until rOJ becomes rOJ, and when the subtraction result 5GET-3NOW becomes rOJ, the CPU 44b executes rN in step 73.
It is determined that it is OJ and the program proceeds to step 76. Through such circulation processing, when the determination is "NO" in step 73, the current rotation step number data 5NOW
is set to the target rotation step number 5GET, and the rotation step number of the step motor 33 is set to the target rotation step number 5.
Set to GET.

As described above, by rotating the rotor 33b clockwise, the number of rotational steps of the step motor 33 in the reference state is set to "0".
As a result of setting the larger target rotation step number 5 GET, the plunger 34 at the highest point is moved to the step motor 3.
When the retainer 37 descends to a position corresponding to the number of rotation steps of 3, the retainer 37 also descends to a position corresponding to the same number of rotation steps by the action of the spring 38, and the valve body 36 and the valve seat part 3
2b, that is, the hose 39a from the atmosphere, the cylinder body 32a1 of the control valve device 30, the hose 39b1, the carburetor 20
The amount of air bleed flowing into the fuel passage 21a through the air bleed passage 21b is set and controlled according to the target rotation step number 5GET.

The air-fuel ratio of the air-fuel mixture formed in the intake shell 21 of the carburetor 20 is set to the optimum value by this set and controlled air bleed amount, so that the air-fuel ratio of the air-fuel mixture that is supplied from the carburetor 20 to the engine is The air-fuel ratio is controlled to the optimum value according to the cooling water temperature Tw.

Note that if the target rotational step number 5GET calculated above is rOJ in step 72, the current rotational step number data 5NOW is set to rOJ by the processing of the above-mentioned "initial control routine".
Since it is set to OJ, the subtraction result 5GET-3NOW in the process of step 73 becomes "0", and the CPU 4
4b, after the processing of the stave 72, the determination in step 73 is "NO" and the program proceeds to step 76. In this case, since the processing of steps 74 and 75 is not executed, the current rotational step number data 5NOV remains set to rOJ equal to the target rotational step number 5GET, and the step motor 33 also remains set to the reference state. .

After determining "NO" in step 73 as described above, the CPU 44b determines the current rotation step number data 5 from the target rotation step number 5 GET calculated above in step 76.
The number of rotational steps of the step motor 33 represented by NOW is subtracted, and the subtraction result 5GET-3NOW is rOJ
Determine whether it is smaller. In this case, step 73
Through the processing of ~75, the subtraction result 5GET-3NOW is r
Since it is OJ, the CPU 44b executes r at the same step 76.
The determination is NOJ and the program returns to step 70. In step 70, the CPU 44b determines whether the detected cooling water temperature Tw is higher than 20 degrees Celsius, as described above. In this case, the cooling water temperature Tw once exceeds 20 degrees Celsius is
As long as the engine is operating, the temperature will not normally fall below 20 degrees Celsius, so the CPU 44b makes a determination of "rYES" at step 70 and advances the program to step 71. Note that when the cooling water temperature Tw falls below 20 degrees Celsius, the CPU 44b continues to repeatedly execute the process of step 70 as described above, and when the cooling water temperature Tw exceeds 20 degrees Celsius during this execution, , the program advances to step 71.

At step 71, the CPU 44b, as described above,
It is determined whether the detected cooling water temperature Tw is less than 60 degrees Celsius. And if the water temperature Tw is less than 60 degrees Celsius,
As described above, the CPU 44b calculates the target rotation step number 5 GET based on the cooling water temperature TV in step 72, and advances the program to step 73. Step motor 33 represented by step number index 5NOW
If the number of rotation steps is greater than
44b determines "YESJ" in step 73 and continues executing the circulation process consisting of steps 73 to 75. As a result of the execution of this circulation process, as described above, the rotor 33b is , is rotated one step in the right direction, that is, in the opening direction of the control valve device 30, and the current rotation step number data 5NOW is incremented by "1" by the process of step 75 and is always set equal to the rotation step number of the step motor 33. be done. During this circulation process, when the current rotation step number data 5NOW, which increases with the clockwise rotation of the rotor 33b, becomes equal to the target rotation step number 5GET, the CPU 44b proceeds to step 73.76 as described above. The determination is "NO" in each case, and the program returns to step 70.

On the other hand, the target rotation step number 5 calculated in step 72
GET, contrary to the above, the current rotation step number data 5N
If it is smaller than the number of rotational steps of the step motor 33 represented by OW, the subtraction result 5GET-3NOW obtained by the processing in step 73 becomes negative, and the CPU 44b determines rNOJ in step 73 and advances the program to step 76. At step 76, the CPU 44 b
As mentioned above, the subtraction result 5GET-3NOW is "0"
In this case, as mentioned above, the subtraction result 5GET-3NOW is negative, so rYE
It is judged as sJ. After this determination, in step 77, the CPU 44b moves the rotor 33b in the left direction, that is, in the closing direction d1 of the control valve device 30, contrary to the process in step 74.
A control signal for step rotation is output to the drive circuit 47 via 11044d. The drive circuit 47 connects the rotor 3
A drive signal for rotating the rotor 33b one step to the left is output to the step motor 33, and the rotor 33b rotates one step to the left. After processing in step 77, CPU4
4b is the current rotation step number data 5 at step 78.
By subtracting "1" from HOW, the current rotational step number data 5NOW is made to match the number of rotational steps accompanying the left rotation of the step motor 33, and the program returns to step 76. Then, the CPU 44b performs step 76.
The current number of rotational steps of the step motor 33 represented by the updated current rotational step number data 5NOW is subtracted from the target rotational step number 5GET, and the new subtraction result 5GET-3NOW is compared with "0". Step 7 until the subtraction result 5GET-3NOW becomes "0".
The cyclic processing consisting of steps 6 to 78 continues to be executed. As a result of this circulation process, contrary to the circulation process consisting of steps 73 to 75, the rotor 33b is
The control valve device 30 is rotated one step in the left direction, that is, in the closing direction of the control valve device 30, and the current rotation step number data 5NOW is
"1" is subtracted by step 78 and the step motor 3
It is always set equal to the number of rotation steps of 3. and,
During this circulation process, when the current rotation step number data 5NOW, which decreases as the rotor 33b rotates to the left, becomes equal to the target rotation step number 5GET, the CPU 44b
As described above, in step 7-6, it is determined as NOJ, and as long as the cooling water temperature TW is less than 60 degrees Celsius, the circulation process of steps 70 to 78 is executed.

Note that the target rotation step number 5 calculated in step 72
If GET is equal to the number of rotational steps of the step motor 33 represented by the current rotational step number data 5NOW, the CPU 44b outputs rNO in steps 73 and 76.
J is determined and the program returns to step 70. In this case, the number of rotation steps of the step motor 33 and the current number of rotation steps data 5NOW are not updated. From then on, as above, as long as the cooling water temperature Tw is less than 60 degrees Celsius, CP
U44b executes the cyclic processing of steps 70-78.

During the circulation process, the CPU 44b controls the rotor 33b to rotate clockwise through the processes of steps 73 to 75, or controls the rotor 33b to rotate counterclockwise through the processes of steps 76 to 78, thereby directing the rotor 33b to the fuel passage 21a of the carburetor 20. Since the inflowing air bleed amount is set and controlled according to the target rotation step number 5 GET, the air-fuel ratio of the air-fuel mixture formed in the intake cylinder 21 of the carburetor 20 is set to an optimal value. the result,
In a state where the cooling water temperature Tw is between 20 degrees Celsius and 60 degrees Celsius, the air-fuel ratio of the mixture supplied from the carburetor 20 to the engine is adjusted according to the cooling water temperature Tw by the circulation processing in steps 71 to 78. Optimally controlled.

Further, during such circulation processing, if the cooling water temperature Tw rises to 60 degrees Celsius or higher, the CPU 44b executes step 7.
1 is determined as "NO", and in step 79, an oxygen concentration detection signal is fetched from the oxygen concentration sensor 43 via 1044d, and by integral and proportional control according to the detection signal,
The number of rotational steps of the step motor 33 is controlled. That is, while the oxygen concentration detection signal continues to be at a high level (or low level), the rotor 33b gradually moves one step at a time in the right (or left) direction, that is, in the opening (or closing) direction of the control valve device 30. The number of rotational steps of the step motor 33 is integrally controlled according to the oxygen concentration detection signal. Further, at the time when the oxygen concentration detection signal changes from low level (or high level) to high level (or low level), the rotor 33b moves in the right (or left) direction, that is, in the opening (or closing) direction of the control valve device 30. The rotation of several steps is controlled almost simultaneously, and the step motor 3
The number of rotation steps of 3 is proportionally controlled according to the oxygen concentration detection signal. Through such integral and proportional control, if the air-fuel mixture supplied to the engine is rich (or lean), the amount of air bleed flowing into the fuel passage 21a of the carburetor 20 is controlled to be large (or small). , the air-fuel ratio of the air-fuel mixture is controlled to be the stoichiometric air-fuel ratio. Note that when controlling the number of rotational steps of the step motor 33, the current rotational step number data 5NOW is also
The current rotation step number data 5NOW is always maintained to represent the rotation step number of the motor 33.

After the processing in step 79, the CPU 44b advances the program to step 71 and determines that the cooling water temperature Tw is 60 degrees Celsius.
As long as the oxygen concentration is higher than the oxygen concentration, the circulation processing in steps 71 and 79 continues to be performed, and the air-fuel ratio of the air-fuel mixture supplied to the engine is feedback-controlled to the stoichiometric air-fuel ratio based on the oxygen concentration detection signal.

As can be understood from the above explanation of the operation, according to the above embodiment, the step motor 33 like the above conventional device
Immediately after the engine starts, the step motor 33 can be reliably operated by only the program processing corresponding to the "initial control routine" consisting of steps 60 to 68 stored in the ROM 44a, without using a position sensor to detect the reference state of the engine. The current rotational step number data 5HO is set to the reference state and is used to monitor the rotational step number of the motor 33.
W is set to a reference value rOJ corresponding to the reference state. After the processing of this "initial control routine", the air bleed amount of the engine is determined based on the current rotation step number data set as the reference value by the processing of the "air bleed control routine" consisting of steps 70 to 79. Since the control is performed according to the operating state, the cost of the air bleed control device according to the above embodiment is reduced by eliminating the need for the position sensor. In addition, as the position sensor is no longer necessary, improper control of the air bleed amount due to failure of the position sensor as in the conventional device described above is eliminated, and the air-fuel ratio of the air-fuel mixture supplied from the carburetor to the engine is eliminated. is always accurately controlled, reducing harmful exhaust gas components emitted from the engine, improving drivability, and improving fuel efficiency.

In the above embodiment, the air bleed amount was controlled only based on the engine cooling water temperature and the oxygen concentration in the exhaust gas, but in addition to these controls, the amount of air bleed flowing into the carburetor 20 from the air cleaner The amount of air bleed may be controlled in accordance with other factors representing the operating state of the engine, such as the temperature of the air flow and the negative pressure within the carburetor 20. In this case, the temperature and negative pressure correction rotation step number of the step motor 33 is determined based on the detected temperature signal from the temperature sensor that detects the temperature of the air flow and the detected negative pressure signal from the negative pressure sensor that detects the negative pressure. The number of rotational steps of the step motor 33 may be corrected according to each corrected number of rotational steps by using the current rotational step number data 5NOW. As a result, the amount of air bleed flowing into the carburetor 20, that is, the air-fuel ratio of the air-fuel mixture supplied from the carburetor 20 to the engine, is appropriately controlled depending on the engine operating conditions such as the temperature and negative pressure of the air flow. It becomes like this.

Further, in the above embodiments, an example in which the air bleed control device according to the present invention is applied to a main fuel system has been described, but the air bleed control device according to the present invention can also be applied to a slow fuel system. In this case, slow port plug 2
7 is provided with an air bleed passage that penetrates the plug 27 and communicates the outside of the carburetor 20 with the slow port 21c,
The passage is communicated with the atmosphere through a control valve device having a step motor as in the above embodiment, and the micro combinator 44 controls the step motor when starting the engine as in the above embodiment. It is preferable to set the reference state to the reference state, and then control the number of rotational steps of the step motor according to the operating state of the engine.

[Brief explanation of drawings]

FIG. 1 is a diagram corresponding to the configuration of the invention described in the claims, FIG. 2 is a diagram showing an embodiment of the invention, and FIG.
FIG. 4 is a flowchart corresponding to the program executed by the microcomputer shown in the figure, FIG. FIG. Description of symbols 20... Carburizer, 21... Intake cylinder, 21a... Fuel passage, 21b... Air bleed passage, 23... Fixed venturi, 24... Float chamber, 30... Control valve device, 32a...Cylinder body, 32b...Valve seat portion, 33
... Step motor, 36... Valve body, 40... Electric control device, 41... Engine rotation speed sensor, 42...
...Water temperature sensor, 43...Oxygen concentration sensor, 44...
・Microcomputer, 46...Battery. Applicant Aisan Kogyo Co., Ltd. (1 other person) Agent Patent attorney Teru Hase - (1 other person) Figure 4 V At the start of startup → Time 5rjA

Claims (1)

[Claims] The vent lily provided in the intake passage of the carburetor or its downstream part is interposed in a communication passage that communicates with the atmosphere, and the opening degree controls the amount of air bleed that flows from the atmosphere into the bench lily or its downstream part through this communication passage. a flow rate control means that is connected to the flow rate control means and controls the flow rate control means in response to an increase in the number of rotation steps in one direction based on the minimum opening degree of the flow rate control means; a step motor that increases the opening degree; a storage means that stores data representing the current number of rotation steps in the one direction that is actually set by the step motor; a target number of rotational steps determining means for determining a target number of rotational steps in the one direction to be set by the step motor; and a current number of rotational steps represented by the determined target number of rotational steps and data stored in the storage means. outputs a rotational drive signal to the step motor in accordance with the difference between the step motor and controls the number of rotational steps of the step motor in the one direction to the determined target number of rotational steps, and also sets the stored data value of the storage means to the determined number of rotational steps. In the air bleed control device for a carburetor, the step motor is rotated in a direction opposite to the one direction when the engine is started, and the flow rate control means is configured to rotate the step motor in a direction opposite to the one direction when the engine is started. a first outputting a rotational drive signal to the step motor to minimize the opening degree of the step motor;
an output means, a complete explosion detection means for detecting a complete explosion state of the engine, and a rotation for rotating the step motor in the opposite direction to minimize the opening degree of the flow rate control means when the complete explosion state is detected. a second output means for outputting a drive signal to the step motor; and a second output means for outputting a drive signal to the step motor; 1. An air bleed control device for a carburetor, comprising: a reference rotation step number setting means for setting a step number.