JPS59185853A - Mixture gas regulator of carburettor - Google Patents

Abstract

PURPOSE:To have sure and quick return to the normal revolving speed of an engine from eventual drop of the speed likely to occur during idling, by opening a throttle valve to a specific angle in immediate response thereto. CONSTITUTION:A mixture gas regulator of a carburettor is equipped with a comparator 180, No.7 memory 181, mono-multi 182, No.8 memory 183 and an adding device 184. In said No.7 memory 181 is stored a lower limiation value Ne1 which shall serve as reference for the opening control for throttle valve in the event of excessive drop of the number of revolutions of the engine. The comparator 180 compares the number of revolutions of the engine Ne with said lower limitation value Ne1, and if the former is smaller an output will be emitted to trigger the mono-multi 182. The No.8 memory 183 supplies the number of correction pulses to said adding device 184 in response to the output pulse from the monomulti 182, and the adding device 184 adds the number of correction pulses to the output given by No.4 memory 136.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mixture adjustment device for a carburetor, and in particular, a choke valve is provided on the upstream side of the intake path and a throttle valve is provided on the downstream side of the venturi portion where the main fuel nozzle opens. In the installed carburetor, the opening degrees of the choke valve and the throat valves are controlled by two cams fixed to the electric output shaft or its reduction type output shaft. The present invention relates to a mixture adjustment device for a container.

As mentioned above, the J3 is installed in a carburetor with a choke valve installed on the upstream side of the intake passage and a throttle valve installed on the downstream side, with the venturi part where the main combustion nozzle opens as the boundary,
The choke valve is linked with a first rotary cam means that can operate the choke valve from a fully open position to a fully open position, and the throttle valve has a second rotary cam means that can operate the throttle valve to a predetermined fast idle opening degree. These first
and a second rotary cam means connected to an electric motor whose rotational position is determined depending on the operating conditions of the internal combustion engine, the electric motor adjusting the air-fuel mixture from a home position as a boundary. Can be rotated and reversed,
The first and second rotary cam means are configured such that when the electric motor rotates forward from a home position, the choke valve is held at a substantially fully open position, while the throttle valves 1 to 1 increase their opening degrees; In addition, the shape of the choke valve is selected such that when the electric motor is reversed from the home position, the choke valve decreases its opening degree, while the throttle valves increase their opening degree. Regarding the structure of the carburetor part of the carburetor mixture adjustment device and the configuration and operation of the electrical control circuit, see, for example, Japanese Patent Application No. 57-1148.
It is explained in detail in the specification of No. 06.

FIG. 1 is a block diagram of an electrical control circuit of a conventional air-fuel mixture adjustment device for a carburetor, and FIG. 2 is a flowchart for explaining its operation. First, with reference to FIGS. 1 and 2, an overview of the operation of the conventional example will be described below.

When the ignition switch (not shown) is turned on when starting the engine, the ignition switch detector 1
24 detects this, and the output of the edge detection circuit 130 sets the 1711th block flop 145.

This causes the first AND gate 149 to be heard. Further, since the seventeenth lip flop 145 is set, the memory selector 139 selects the fifth memory 137.

On the other hand, at this time, in step S1 of FIG. 2, the open/closed state of the home position switch (not shown) is determined.

That is, for example, if the Bauhm position switch is closed, the Bauhm position switch detector 125 is '1'.
This signal is applied to the output controller 141 via the first AND gate 149.

As a result, the output controller 141 outputs a pulse in the direction of reversing the stepping motor 142 (
Step S2 in FIG. 2).

When the stepping motor rotates in reverse, the stepping motor 142 passes through a predetermined Baum position, and at this time the home position switch is opened.

As a result, the output of the home position switch detector 125 becomes 0'', and the first AND gate 149 is closed.As a result, the output controller 141 outputs a pulse that causes the stepping motor 142 to rotate forward (as shown in FIG. Step 83).

When the stepping motor 142 rotates normally, it is determined when the home position switch changes from open to closed (step 84 in FIG. 2).

In the circuit of FIG. 1, this change is detected by the first differentiating circuit 131, the first flip-flop 145 is reset, and the first ANDs 1-149 are closed.

In addition, in the determination of step S1, if the home position switch is not closed, the first AND gate 1
Since the output of 49 is '0'', the stepping motor 142 rotates forward and when it reaches the home position,
The home position switch changes from closed to closed, and the same operation as described above is performed.

On the other hand, at the same time as the first flip-flop 145 is reset by the output of the first differentiating circuit 131, the preset value (value for initial setting) of the fifth memory 137 is set in the U/D counter 143.

In this way, the initialization of this device is completed.

That is, the home position of the stepping motor 142 and the preset value (initial value) of the U/D counter 143 are accurately matched (step 85 in FIG. 2).
. At the same time, in step S5 of FIG. 2, the hot flag is reset.

When initialization is complete, engine speed sensor 1
The output of No. 21 is applied to the complete explosion detector and delay circuit 126, and it is determined that the complete explosion state has not been reached - that is, that the engine speed Nc is smaller than the set value Neo (second Step 86) in the figure.

Further, the output of the engine temperature sensor 123 is compared with the set value TO in a first comparator 127 to determine whether the engine is in a cold state or a hot state (
Step S7 in FIG. 2).

When the engine temperature is lower than the set value TO of the first comparator 127 and is in a cold state, the first comparator 1
The output of 27 becomes P O''' and the second flip-flop 1
46 is reset. In response, the memory selector 139 selects the first memory 133 for cold start (step S8 in FIG. 2).

Since the first memory 133 stores the rotational position data of the stepping motor 142 corresponding to the engine temperature, the data most detrimental to the engine temperature at that time is output and supplied to the third comparator 140. .

The third] comparator 140 compares the data with the count value of the U/D (up/down) counter 143, and sends an output according to the difference to the output controller 1/11 and the U/D counter 143, respectively. Provided as reverse signal and up/down count signal.

Thereby, the stepping motor 142 is rotated to a position equal to the read data of the first memory 133.

Therefore, a cam plate (not shown) fixed to the output shaft of the stepping motor 142 rotates, and as each cam rotates, the choke valve and throttle valve (both not shown) operate at the respective times. The opening degree is set to be optimal for cold starting according to the engine temperature (steps S8→S11→533 in FIG. 2).

An example of the relationship between the rotational position of the stepping motor 142 and the opening degrees of the choke valve and throttle valve is shown in FIG.

In the figure, the horizontal axis indicates the rotational position of the stepping motor 1/i2, and the Δ mark indicates the home position. The vertical axis is the throttle valve opening θth and the choke valve opening θch.
It is. If the stepping motor 142 is rotated in the opposite direction from the home position, the valve opening degree suitable for a cold state can be obtained. Further, if the valve is rotated in the forward direction, a valve opening degree suitable for a hot state can be obtained.

Further, in the determination in step S7 of FIG. 2, if the engine temperature is higher than the set value TO of the first comparator 127, the engine is in a hot state.

At this time, the output of the first comparator 127 becomes 1'', and in response to this, the memory selector 139 sets the third memory 135 for hot starting () and sets the hot flag (step 2' in Figure 2'). S9-→810).

The rotational position data of the stepping motor 142 for hot starting is stored in the third memory 135 and is supplied to the third comparator 140. This causes the stepping motor 142 to operate in the same manner as described above.
is rotated to a position equal to the data (L outlet) of the third memory 135 (step 59-) 310 → S in FIG.
11 → 833).

When the starter switch (not shown) is closed in this state, the engine is started and its rotational speed increases.

The engine speed is detected by an engine speed sensor 121, and a complete explosion detector and delay circuit 126 determines whether the engine is in a complete explosion state (i.e., step S6 in FIG. 2). As shown, it is determined whether the engine rotational speed Neh is greater than the stall detection value NeO.

Steps S6→S7−→S8→ until the complete explosion state is reached.
Is it a loop of S11 → 833?
6→S7→S9→810-Saki511-) Repeat the loop of S33.

When the complete explosion state is reached, the determination bX in step S6 is established, so the process advances to step 321. After the complete explosion delay time has elapsed, the process proceeds to step 822, where it is determined whether the hot flag is set or not.

When the engine is started in a cold state (well, since the hot flag is not set, proceed to step S24,
It is determined whether the engine temperature has risen above the cold/hot boundary temperature TO.

If the engine temperature is below the cold boundary temperature To, the process proceeds to step 825 and the second memory 134 for warm-up is selected.

In the device of FIG. 1, this means that the complete explosion detector and delay circuit 126 produces an output and that the first comparator
This is done by causing the memory selector 139 to select the second memory 134 under the two conditions that the output of 7 is '0''.

As is clear from FIG. 1, the second memory 134 includes the intake air temperature sensor 122 and the engine temperature
3 is supplied as a parameter, and the rotational position data of the stepping motor 142 is read out.

Then, as described above, the stepping motor 142 is driven according to this read data, and the opening degree control of the choke valve and throttle valve is executed (step 533 in FIG. 2).

As the engine continues to rotate, its temperature gradually rises. If the engine temperature rises by the time the determination in step S24 in FIG. Determine whether the

If the accelerator switch is not closed, step 82
5, proceed to step 833 and do not repeat the above operation.

When the accelerator switch is closed, step 3
Proceed to 27. Then, the engine rotation speed Ne becomes a predetermined value N
It is further determined whether it is greater than el. If the determination is not satisfied, the process similarly advances to steps 825 and 833 to execute a warm-up cycle.

Once the determinations in steps S26 and S27'c are established, the process proceeds to step 828. That is, the initial idle value stored in the sixth memory 138 in FIG.
, and further controls the rotational position of the stepping motor in step S33.

'Mh exploding size rod 1a-y = r to → size ha 1
−〜・−! --I can sleep.

When the engine temperature rises, the engine temperature sensor 123
The output of the first comparator 127 is inverted and becomes ll 1 I+. On the other hand, when the engine speed increases, the output of the engine speed sensor 121
becomes larger, and the output of the second comparator 132 becomes 1''.
become.

Therefore, the output of the accelerator switch detector 128 is 1″
, the second AND gate 144 generates an output of ``1'', and the second flip-flop 146 is turned on. As a result, the memory selector 139 selects the fourth memory 136 for idle speed correction. .

Roughly speaking, the selection output of the memory selector 139 is the second
It is also supplied to a differentiating circuit 148 at the same time, and a third flip-flop 147 is set by its output.

The output of the flip 70 tube 147 is inverted and fed to the third AND gate 150, which closes it. Therefore, the read data of the fourth memory 136 is not supplied to the output controller 1/11.

On the other hand, the output of the third flip-flop 147 activates the sixth memory 138 for idle initial value setting, and the read data is supplied to the third comparator 140. In this way, the stepping motor 142 is driven to the rotation angle for setting the idle initial value stored in the sixth memory 138.

When the stepping motor 142 actually rotates and reaches the initial idle value, the output of the third comparator 140 is generated, thereby resetting the third flip-flop 147. As a result, the third AND gate 150 is heard, so that the data in the fourth memory 136 is supplied to the output controller 141.

As described above, the fourth memory 136 stores the rotational position correction data of the stepping motor 142 using the engine speed as a parameter, so if the engine speed deviates from the predetermined idle speed, , the stepping motor rotation amount or the number of drive pulses necessary to correct this is supplied to the output controller 141.

However, even if the stepping motor 142 is driven to adjust the opening degrees of the choke valve d5 and the throttle valve, the rotation speed does not change suddenly due to the inertia of the engine. For this reason, after changing the rotational position of the stepping motor, it is desirable not to perform the next control for a certain period of time.

Step 831 in FIG. 2 is for setting such a grace period, and the rotation angle correction of the stepping motor in step 833 is not executed until the scheduled time has elapsed, and the process returns to step S6.

In FIG. 1, a similar grace period can be provided by controlling the operation timings of the output controllers 1 to 1/11 and/or the third AND gate 150 using an appropriate timer or sequencer.

If it is determined in step S31 that the scheduled time has elapsed, a timer for measuring the scheduled time is cleared in step 832, and step S33
Proceed to. Then, step 83
It is driven according to the data read from the M4 memory 136 at 0.

As described above, the transition from cold control to idle operation is performed.

As is clear from the above explanation, in the conventional carburetor air-fuel mixture adjustment device A5, the transition from the cold region to the Bauhm position to the hot region or idling region requires that the accelerator switch be turned on. It is done while it is happening.

Therefore, the opening degree of the throttle valve is set to the initial idle value in the hot region without decreasing to the lowest value near the home position. Therefore, during the above-mentioned transition, there is no fear that the opening surface of the throttle valve will be insufficient and the rotational speed will drop too much or that the engine will stop.

In this way, in the conventional carburetor mixture adjustment device, the driving direction and driving amount of the stepping motor 142 are directly retrieved from memory according to the deviation of the engine speed from the set value, and the idling is adjusted based on this data. Since the rotation speed during operation is controlled, an extremely stable idle rotation speed can be achieved.

Furthermore, since the opening degrees of the throttle valve and choke valve can be controlled by uniaxial drive, the structure can be simplified and costs can be reduced.

Note that the above-mentioned carburetor air-fuel mixture adjustment device may be modified and implemented as follows.

(+) Initial setting of the U/D J counter 143 is performed at a timing between when the Bauhm position switch is closed.

(2) The first memory 133 for cold starting stores the opening degree of the throttle valve using the output of at least one of the intake air atmosphere temperature sensor 122 and the engine temperature sensor 123 as a parameter.

(3) The second memory 134 for warming up stores the opening degree of the throttle valve using at least two of the outputs of the engine speed sensor 121, the intake atmosphere temperature sensor 122, and the engine temperature sensor 123 as parameters.

(4) The third memory 135 for hot starting stores the opening degree of the throttle valve using at least one of the outputs of the intake air atmosphere temperature sensor 122 and the engine temperature sensor 123 as a parameter.

(5) The sixth memory 138 for idle initial value setting uses at least one of the outputs of the intake air temperature sensor 122 and the engine temperature sensor 123 as a parameter.
Store the opening degrees of the throat valves 1 to 1.

The sixth memory 138 stores the rotational position of the stepping motor 142 immediately before shifting to idle operation and the opening degrees of the C1 throttle valves using the data in the fourth memory 136 as parameters.

(6) Instead of detecting the activation of the accelerator switch, it detects that the thrower lever is not engaged with the interlocking lever.

(7) The conditions for transition from the cold region to the hot region are: (a) the engine temperature is higher than the scheduled value, and (b) the rate of increase in J5 and engine speed is higher than the scheduled value. One may be adopted.

(8) A hysteresis characteristic is provided to the transition condition from the cold region to the hot region, or vice versa, to prevent hunting near the boundary between the cold and hot regions.

As mentioned above, in the conventional carburetor mixture adjustment device,
After executing control switching from cold area to hot area,
Correction control of the throttle valve opening is performed using the deviation of the engine speed from the target value as a parameter. As a result, the engine speed is maintained at the predetermined idle speed.

However, if some kind of disturbance occurs while the engine is idling, and as a result the engine speed drops rapidly and significantly, the control response will be delayed, and the speed will not recover immediately, resulting in the engine stopping, etc. It may come to that.

In order to avoid this, it is possible to set the response speed of the control system to be high, but in this case, when the rotation speed deviation is large, it is likely to overreact and cause hunting, which may actually reduce the stability of the control system. This has the drawback that the engine's operating performance is reduced.

The present invention has been made to improve the above-mentioned drawbacks, and its purpose is to reduce the normal response delay of the control system when the engine speed suddenly decreases during engine idling. Another object of the present invention is to provide a mixture adjustment device for a carburetor that can quickly return the engine speed to a target value and effectively prevent hunting from occurring in the engine speed.

In order to achieve the above object, in the present invention, during engine idling, the engine speed is set to a predetermined lower limit value (this value is, of course, a reference engine speed for detecting a complete explosion). The throttle valve is opened by a predetermined angle unconditionally when the engine speed drops below (chosen larger than the number). This prevents the engine speed from dropping abnormally and reduces the engine speed and stepping motor. This prevents hunting from occurring.

The present invention will be explained below with reference to the drawings. FIG. 4 is a block diagram of one embodiment of the present invention, and 1 and 2 in FIG. 5 are flowcharts for explaining the operation of FIG. 4.

In these figures, the same reference numerals as in FIGS. 1 and 2 represent the same or equivalent parts.

As is clear from comparing FIG. 4 with FIG. 1, this embodiment has a comparator 180,
7th memory 181, monomulti 182, 8th memory 18
3 and an adder 184 are added.

The seventh memory 181 stores a lower limit value Ne1 that serves as a reference for controlling the amount of the throttle valve when the engine speed drops below that value.

The comparator 180 sets the engine rotation speed NO to the lower limit value Ne1.
When the former becomes smaller, an output is generated and the monomulti 182 is triggered.

The eighth memory 183 stores the number of correction pulses necessary to adjust the throttle valve to a predetermined angle when the engine speed becomes lower limit value Ne1 or less.

Then, the eighth memory 183 supplies the corrected pulse number to the adder 184 in response to the output pulse of the monomulti 182. The adder 184 adds the number of corrected pulses to the fourth
Add to the output from memory 136.

In addition, FIG. 5 shows each processing step of the conventional example in FIG.
This corresponds to the addition of steps 522A, 822B, and 522C.

During operation, after the engine is started and transitioned from cold control to hot control as described above, in other words, while the stepping motor 142 is being controlled by the output of the fourth memory 136, the engine rotation is The engine speed signal from the number sensor 121 and the seventh memory 181
A comparator 180 compares the lower limit value Ne1 from .

While the engine speed signal is greater than the lower limit Ne1, the comparator 180 does not produce any output, and the output from the 8th'' memory 183 to the adder 184 is O, so the operation is as usual.

In FIG. 5, in step 522A, the lower limit value Ne1 is read from the seventh memory, and in step 322B,
This is done by comparing the lower limit value Nel and the engine speed Ne.

If the engine speed Ne is not smaller than the lower limit Ne1,
The process advances to step S30 and is exactly the same as the conventional process.

When the engine speed Ne becomes smaller than the lower limit Ne1, the comparator 180 produces an output, which triggers the monomulti 182 and activates the eighth memory 183. Accordingly, the eighth memory 183 outputs a predetermined number of correction pulses to the adder 184.

Therefore, the fourth memory 136
The number of correction pulses is added to the number of idle rotation speed correction output pulses output from the stepping motor 142.
is driven to open the throttle valve an additional predetermined angle.

The above operations are performed in step 822G in FIG.

That is, if it is determined in step 322B that the engine speed is smaller than the lower limit value Ne1, the number of correction pulses for increasing the throttle valve opening by a predetermined amount is set from the eighth memory. . Subsequently, in step 833, the stepping motor is driven based on the settings.

As is clear from the above description, according to the present invention, the following effects are achieved.

(1) Even if the engine speed suddenly drops due to some kind of disturbance during idling, the throttle valve is opened by the predetermined angle in response immediately, so the engine speed can be returned to normal speed quickly and reliably. This prevents the engine from stopping (stall).

(2) Since there is no need to make the sensitivity of the control system excessively high in the normal control state, the stability of the control system can be maintained well.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an example of a conventional air-fuel mixture adjustment device for a carburetor, Fig. 2 is a flowchart for explaining an example of its operation, and Fig. 3 shows the rotational position of the stepping motor and the position of the choke valve and throttle valve. 4 is a block diagram showing an embodiment of the present invention, and 1 and 2 in FIG. 5 are time charts of a lifting platform in which the present invention is implemented using software such as a computer. be. 121... Engine rotation speed sensor, 122... Intake atmosphere temperature sensor, 123... Engine temperature sensor,
124...Ignition switch detector, 125.
... Bauhm position switch detector, 126 ... Complete explosion detector and delay circuit, 128 ... Accelerator switch detector, 13o ... Edge detection circuit, 133 ... First memory, 134 ... No. 2 memory, 135...3rd
Memory, 136...Fourth memory, 137...Fifth memory, 138...Sixth memory, 139...Memory collector, 141...Output controller, 17!1.2
...Stepping motor, 143...U/D counter, 180...Comparator, 181 River 7th memory, 182
...Mono multi, 183...8th memory, 184.
・Adder representative patent attorney Michito Hiraki and 1 other person 3

Claims (2)

[Claims] (1) A choke valve is installed on the upstream side of the intake passage, and a throttle valve is installed on the downstream side of the intake path, with the venturi part where the main fuel nozzle opens as a boundary, and the throttle valve is set to a predetermined opening degree. interlocking rotary cam means that can
The rotating cam means is connected to an electric motor whose rotational position is determined according to the operating conditions of the internal combustion engine, and the electric motor can rotate forward and backward from a home position, and The cam means is a mixture adjusting device for a carburetor that causes the throttle valve to increase its opening when the electric motor rotates forward from a home position, and is selected when the internal combustion engine is in an idling operating state. ,
a first memory means for outputting a signal corresponding to the corrected rotation speed of the electric motor using a deviation of the engine rotation speed from a scheduled value as a parameter; a second memory means for outputting a correction signal for driving the electric motor by a predetermined amount in the normal rotation direction in response to the output of the comparison means; 1. A mixture adjusting device for a carburetor, comprising: means for adding output signals of the first and second memory means; and means for driving the electric motor based on the sum output signal of the adding means. (2) The air-fuel mixture adjusting device for a carburetor according to claim 1, wherein the lower limit value is larger than a rotational speed for determining complete explosion of the engine.