JPH0239619B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is an engine equipped with an alternator, which is capable of controlling the engine rotational speed by preventing the engine rotational speed from decreasing when an electrical load is applied. This relates to a control device.

(Prior art) Conventionally, in automobiles, the engine speed is controlled to a constant value by detecting the input timing of the engine load of an air conditioning compressor or the like during idling operation, and correcting the intake air amount, fuel, etc. accordingly. There is an engine speed control device designed to do this.

Among them, for example, Japanese Patent Application Laid-Open No. 54-98413 is an attempt to prevent the engine speed from decreasing when the engine load suddenly increases due to turning on an air conditioning compressor or changing the shift lever of an automatic car. There is something shown in the publication.

This conventional technology provides a separate intake control valve to directly and forcibly correct the intake air amount without going through the normal engine control loop in order to speed up the response on the engine side. It is designed to operate according to load input timing such as turning on or switching the shift lever.

However, in the case of this conventional technology, even if the amount of air supplied to the engine is quickly determined at the load input timing, it takes a long time before the engine can actually respond.
After all, a certain amount of time is required, which inevitably causes a follow-up delay. As a result, drawbacks such as a momentary drop in engine speed and stalling cannot be completely eliminated. Therefore, in order to solve this problem, we first detect the input timing of the above load, and from the time of detection until the engine side actually takes action (until the rotation speed increases), the above load is not operated. There was one that applied a delay to prohibit.

However, although this configuration that delays load operation can prevent a temporary drop in engine speed, the delay in load operation itself is not a good thing; Depending on the type of load, it may not be possible to adopt the above configuration.

(Object of the Invention) The present invention has been made in view of the above-mentioned points. In particular, in a device in which an alternator is driven by an engine, it is possible to cause a delay in the operation of the load when an electrical load is input. It is an object of the present invention to provide an engine rotation speed control device that can prevent even a temporary decrease in engine rotation speed.

(Means for Achieving the Object) In order to achieve the above object, the present invention provides a battery that serves as a power supply source for the load when the generated voltage of the alternator is lower than the load voltage, and the generated voltage is lower than the battery voltage. In an engine equipped with an engine-driven alternator that serves as a power supply source for the load when the electrical load is large, a load input detection means for detecting that an electrical load is input; An engine control means for increasing the intake air amount of the engine in response to an electrical load, and a field current control means for controlling an alternator field current to increase in accordance with the input load current value required to drive the electrical load. and operates when the load input detection means detects a load input, and it takes a predetermined time until the engine output reaches a value that can maintain the drive of the input electrical load due to an increase in the engine intake air amount by the engine control means. a field current adjustment that fixes the control value of the field current control means so as to maintain the value of the field current controlled by the field current control means at a predetermined value before the electrical load is input; and means.

(Function) According to the above configuration, when an electrical load is input in the idling operating state, the intake air amount is first corrected to increase the engine, and at the same time the engine speed reaches a predetermined value corresponding to the correction amount. Until this point is reached, the control value of the field current control means is fixed, and the value of the feed current is maintained at the predetermined current value before the load input.

Therefore, even when an electrical load is input, the field current does not increase until the engine speed reaches a sufficient corresponding value, and the alternator no longer becomes a factor in reducing the engine speed. On the other hand, voltage is supplied from the battery to the electrical load at the same time as the input, and the electrical load immediately becomes operational.

(Example) In the drawings, FIGS. 1 to 3 show a first embodiment of the present invention, and FIGS. 4 to 6 show a second embodiment of the present invention.

First, a first embodiment shown in FIGS. 1 to 3 will be explained.

First, FIG. 2 is a system block diagram showing a schematic configuration of the engine speed control device in the first embodiment, FIG. 1 is an electric circuit diagram of the main part thereof, and FIG. This is a time chart of the main parts of the signal in the figure.

In FIG. 2, reference numeral 1 indicates an engine, 2 a cylinder, 3 an intake pipe, and 4 an exhaust pipe. In the intake pipe 3, there is an intake air temperature sensor 6 located in the air cleaner section 5, an air flow meter 7 on the intake downstream side of the air cleaner section 5, and a throttle valve 8 and a throttle opening sensor 9 on the intake downstream side. are provided respectively, and the other exhaust pipe 4 is provided with an O ₂ sensor 10. Further, reference numeral 11 is a fuel injector provided at the engine side end of the intake pipe 3, 12 is a water temperature sensor for detecting the temperature of cooling water, 13 is a solenoid valve for controlling intake air amount, 1
4 is an air valve for fast idle up. The solenoid valve 13 and the fast idle up air valve 14 are each provided in a bypass passage 41 that bypasses the throttle valve 8 in the intake pipe 3. moreover,
Reference numeral 15 is a pressure sensor that uses negative pressure within the intake pipe 3, and reference numeral 16 is an alternator driven by the engine.

Each of the above-mentioned members indicated by reference numerals 6 to 16 is connected to the engine electronic control device 17, and
Based on a predetermined control program, various controls are performed depending on the operating state and load amount of the engine.

On the other hand, the engine electronic control unit 17 is further connected to a load input detection means 20 for detecting input of electrical loads such as a distributor 18 for engine ignition, an igniter 19, and a headlight. Note that the reference numeral 21 is a battery.

Here, the basic operation of the engine 1 shown in FIG. 2 during idling operation will be explained.
The throttle opening degree signal from the engine and the engine speed signal from the distributor 18 (which in this embodiment also serves as the engine speed detecting means in the claims) are input to the engine electronic control device 17, and Therefore, when it is determined that the engine 1 is in the idle operating state, the intake air amount is controlled by the solenoid valve (corresponding to engine control means in the claims) 13 provided in the bypass passage 41, At the same time, the fuel injection amount is also controlled and the idle speed is controlled.

That is, when the engine 1 is in an idling operating state, if the rotational speed of the engine 1 deviates from the set idle rotational speed by turning on and off various loads, the opening degree of the solenoid valve 13 is feedback-controlled, and accordingly The intake air amount and fuel injection amount are controlled so that the engine speed converges to the target speed. In this case, the loads that cause the engine speed to fluctuate include mechanical loads such as air conditioning compressors, and electrical loads such as headlamps and power window motors. Even if there is a load, when the engine speed during idling operation deviates from the set idle speed by turning the load on or off, the above-described feedback control of the speed is performed. In addition, the air valve 1 for fast idle up is provided in parallel with the solenoid valve 13.
4 is maintained at a constant opening independently of the solenoid valve 13 when the engine 1 is in a low temperature state, such as immediately after starting (detected by the water temperature signal from the water temperature sensor 12), and controls the idle speed of the engine 1. It functions to maintain the rotational speed above a predetermined rotational speed, which is higher than the normal idle rotational speed.

Next, the main control circuits of the engine control system shown in FIG. 2 that are relevant to the present invention will be described with reference to FIG. 1.

In FIG. 1, the reference numeral 20 is the load input detection means described above, which detects that the load switch 23 of the electrical load 22 such as a headlight or a motor for a power seat is turned on (see FIG. 3a). A predetermined load detection signal (see FIG. 3b) consisting of, for example, a differential pulse is generated. This load detection signal is supplied to a load correction circuit 24 provided in the engine control circuit shown in FIG. .

The load correction circuit 24 operates in response to the input of the load detection signal, determines a correction amount (increase) in the amount of intake air supplied to the engine, generates an output corresponding to the correction amount, and controls the engine rotation speed control circuit 28. supply to. The engine speed control circuit 28 operates to increase the engine speed by controlling the opening degree of the solenoid valve 13 (FIG. 2) according to the correction amount.

The battery voltage comparison circuit 25 compares the actual battery voltage at the time of load input with reference to the battery voltage limit value required for normal operation of the engine electronic control device 17, and when the actual battery voltage is higher than the reference value, It generates an H output to set the timing adjustment circuit 29 in the next stage, and on the other hand, when the actual battery voltage is below the reference value, it generates an L output to reset the timing adjustment circuit 29.

Further, the engine rotation speed detection circuit 26 detects whether or not the load on the engine side due to the operation of the load correction circuit 24 can be handled, that is, detects the engine rotation speed corresponding to the load amount, and determines whether or not the response state is possible. is determined, and an output is generated (in the embodiment shown in FIG. 1, an H output is generated when the corresponding state is negative).

The timing adjustment circuit 29 has a function as, for example, an AND circuit, and generates an output at the timing when the outputs of the battery voltage comparison circuit 25 and the engine rotation speed detection circuit 26 are both in the H state, and The movable terminal 30 is switched from the contact 27a side to the contact 27b side. On the other hand, the contact 27a of the switching circuit 27 is directly connected to the monostable multivibrator circuit 32, and the other contact 27b is connected to the monostable multivibrator circuit 32 via the field current adjusting means 31. Therefore,
The load detection signal of the load input detection means 20 converted into a differential pulse is generated when the actual battery voltage is equal to or higher than the reference voltage necessary for operating the electronic control unit 17 and the engine speed is at the time of load input as described above. If it does not correspond to the load, the field current is adjusted to the value before the load input by fixing the control value via the field current adjustment means 31 during the time required to respond to the engine (increase in engine speed). After adjustment, it is supplied as a trigger signal to the monostable multivibrator circuit 32, and even if the actual battery voltage is lower than the reference voltage, if the engine speed sufficiently corresponds to the load, it is triggered as is. It will be supplied as a signal to the monostable multivibrator circuit 32. On the other hand, monostable multivibrator circuit 3
2, an engine rotational speed detection signal is supplied from the engine rotational speed detection circuit 26 as a variable duty ratio signal of the oscillation output, and a pulse signal with a duty ratio corresponding to the signal value (Fig. 3c) is supplied.
(see) occurs.

That is, the field current adjusting means 31
drives the monostable multivibrator circuit 32 so as to maintain the value of the field current supplied to the field coil 35 of the alternator 16, which will be described later, at the value before the load input. Then, an output pulse (see Fig. 3c) corresponding to the field current application time corresponding to the load is obtained, and the field current control means 33 is newly activated by this pulse signal, and the field current control means 33 is actuated in response to the load input. Control the current.

On the other hand, the movable terminal 30 of the switching circuit 27
In the normal state on the a side, the field current adjusting means 31 is cut off, and the field current is normally controlled in accordance with the load current.

Next, numeral 34 is a voltage regulating circuit (IC regulator) for the generated voltage of the alternator 16, numeral 35 is a field coil of the alternator 16, and numeral 36 is a diode trio circuit for full-wave rectification of the alternator 16. The L terminal of the voltage adjustment circuit 34 is connected to one side of the field coil 35 and the load side, the F terminal is connected to the other side of the field coil 35, and the E terminal is connected to the ground side. In this example,
The field current control means 33 includes, for example, a resistor R ₁
Drives the transistor Q ₁ inserted on the ground side of the voltage divider circuit consisting of and R ₂ , and this transistor Q ₁
The voltage generated across the resistor _R2 depending on the conduction state of the zener diode ZD (the voltage applied to the Zener diode ZD is controlled in relation to the L point voltage).

That is, considering the low speed rotation state, under normal conditions, transistor _Q1 is ON, and in that case, as is well known, the generated current from alternator 16 is passed through auxiliary diodes _D1 to _D3 . It is supplied to the feed coil 35 and the terminal, and L
It is supplied to the resistors R ₁ and R ₂ on the Zener diode ZD side through the terminal. If the engine speed is still low and the Zener diode ZD does not conduct due to the current value flowing through the resistor _R2 , the current flowing through the field coil 35 as the engine speed increases will remain the same accordingly. Rise. Then, when the voltage across resistor _R2 rises to a value sufficient to make Zener diode ZD conductive, Zener diode ZD becomes conductive, transistor _Q4 turns on, while transistors _Q2 and _Q3 turn off. Therefore, the field current rapidly decreases, and the voltage generated by the alternator 16 also decreases. Thereafter, when the voltage across the resistor _R2 decreases, the Zener diode ZD is turned off again, and the above-described operation is repeated again.

Now, for example, in the above state, when a predetermined control output (for example, L output) is generated from the field current control means 33, the transistor _Q1 is turned OFF, and the field current of the voltage adjustment circuit 34 is (see Figure 3d). In this holding state, the switching circuit 27
This continues until the movable terminal 30 is switched to the contact 27a side, that is, until the engine speed becomes a state corresponding to the load input (see FIGS. 3e and 3f).

In this case, if another load is input outside the field current adjustment time, the corresponding load input detection means 20 generates a differential pulse at the rising edge each time, and at that point The field current adjusting means 31 is configured to operate anew from then on.

Therefore, with the above configuration, even if an electrical load such as a headlamp or a power seat motor is input, the field current will not increase at all until the engine is able to adequately respond to it. does not act as a factor for lowering the engine speed, so the engine speed does not decrease when the electrical load is input.

During this time, current is supplied from the battery 21 to the input electrical load, and the electrical load becomes operational at the same time as the input. Note that the operation of the electrical load by the battery 21 is a temporary reduction until the engine is able to respond to the electrical load (the engine speed actually increases), and normally the time is less than 1 second at most. It is.

When the rotational speed of the engine increases to a predetermined set rotational speed to correspond to the electrical load, a field current corresponding to the electrical load current is supplied as described above. In that case, the engine output required to drive the alternator 16 also increases, but at that time the engine speed is increased to a speed that can sufficiently handle the electrical load, so the input of the electrical load is increased. Problems such as poor idle speed and engine stalling caused by this can be prevented.

In the above description, the field current adjustment time is determined by detecting the engine rotation speed, but a predetermined time may be set using a timer.

Next, a second embodiment of the present invention shown in FIGS. 4 to 6 will be described. This second embodiment realizes the same functions as the first embodiment described above as a control program for an electronic control device. FIG. 4 shows a block diagram of the control circuit of the engine speed control device according to the second embodiment, FIGS. 5A and 5B show a flowchart of its control operation, and FIG. 3 shows a time chart of operating signals of main parts of the control circuit shown in the figure.

First, in FIG. 4, reference numeral 37 is energized by turning on the load switch 23 (see FIG. 6 a), and produces a differential pulse in its rising state (see FIG. 6 b).
This is a differentiating circuit as a load input detection means for obtaining the load input (see reference), and its output pulse is supplied to the monostable multivibrator circuit 38 as a trigger signal.
The monostable multivibrator circuit 38 is triggered by the differential pulse and has a variable transmission time constant by an engine rotation speed detection signal supplied from an engine electronic control device 39, which will be described later. Output pulse (6th
(see FIG. c) and inputs this pulse signal to the engine electronic control device 39.

The engine electronic control device 39 further includes a first
A field current (see FIG. 6d) is detected and supplied from a voltage regulating circuit 36 similar to that in the embodiment, and a battery voltage detecting circuit 40
A battery voltage detection signal is supplied from.

In FIG. 4, the voltage adjustment circuit indicated by the reference numeral 36, as well as the alternator 16, field coil 35, battery 21, etc., have exactly the same configuration as those of the first embodiment shown in FIG. , works similarly.

Next, the above control operation will be explained.

Figure 5A shows the field current detection signal.
The first one performs interrupt operation by turning ON or OFF.
FIG. 5B is a flowchart showing a second control operation in which an interrupt operation is performed by the output signal of the differential circuit 37 as the load input detection means.

Now, if the Zener diode ZD of the voltage adjustment circuit 36 in FIG. 4 is ON, the transistors Q ₂ ,
Since Q ₃ is OFF, no field current flows,
The field current detection signal becomes H, and this H signal indicates that the field current is OFF. On the other hand, the above Zener diode
When ZD is OFF, transistors Q ₂ and Q ₃
Since it is ON, the field current detection signal is L, indicating that the field current is ON, and the detection signal becomes a signal in which these H and L are continuous (see FIG. 6d).

When the field current is turned on, the control program of the engine electronic control unit 39 is interrupted and the first control operation is started.

When the control operation starts, first, in step _S1 , a predetermined interrupt time is set in consideration of the engine response time, and in the next step _S2 , it is determined whether the field current is rising or falling. According to the determination result, in the case of a rise, the L level time (OFF time) from the load input time of the field current to a predetermined time before that is counted (step S ₃ ). next,
Each cycle (OFF time) of each L level signal within the counting time is individually calculated (step S ₄ ).
Then, the average value of the OFF time is calculated by dividing the total value by the number of pieces (step _S5 ).

On the other hand, if the judgment result in step _S2 is falling, first, in step _S6 , the existence time (ON time) of the H level signal from the time of load input to a predetermined time before that is counted, and then in step S6. Count their individual times in _S7 . Then, in step _S8 , the average value thereof is calculated in the same manner as in step _S5 , and in step _S9 , the duty ratio of the two is calculated.

Finally, in step _S10 , the past duty ratio calculated separately in a similar manner is replaced as the current duty ratio. The control operation then returns to its original state.

On the other hand, a second control operation is performed in parallel to the first control operation. In this second control operation, the battery voltage is first detected as in the first embodiment, and the interrupt operation is started on the condition that the detected voltage is equal to or higher than a certain value.

That is, first, in step _S11 , it is determined whether or not the battery voltage is above a certain value, and if it is below the certain value, the duty ratio generating operation of the first control operation is reset (step S12) and the step _S12 is started. At _S13 , the field current control signal (see FIG. 6e) is always maintained in the H state (normal charging state).

On the other hand, if the battery voltage is above a certain value as a result of the battery voltage determination, the monostable multivibrator circuit 3 is triggered by the output of the differentiation circuit 37 as the load input detection means described above.
The interrupt operation is started by the output signal No. 8 (see FIG. 6c), and first, in step _S14 , it is determined whether the signal is rising or falling. Then, in the case of falling, step _S12 is performed in the same way as when the battery voltage is below a certain value with no load input.
Transistor Q ₁ is turned on by S ₁₃ .

On the other hand, when the output of the monostable multivibrator circuit 38 is rising, the data signal is replaced with the past duty ratio (before load input) calculated in the first control operation described above (see T in FIG. 6d). The field current control signal as above transistor
Supply to _Q1 . The transistor _Q1 is driven ON and OFF by the duty ratio of this signal, and when viewed as an average value within a predetermined time until the engine is ready, the field current is ultimately maintained at the constant value before the load input.

Therefore, even when an electrical load is input,
The alternator 16 itself does not immediately become a factor in lowering the engine speed, and the engine speed does not decrease. Moreover, the field current that corresponds to the load current is actually applied only after the correction of the intake air amount on the engine side has been completed and the engine is in a state that can sufficiently handle the load. The decrease in the number can also be sufficiently suppressed. During this time, voltage is supplied from the battery 21 to the electrical load, so it goes without saying that the electrical load itself becomes operational at the same time as the voltage is input.

(Effects of the Invention) As explained above, the present invention provides a battery that serves as a power supply source for the load when the generated voltage of the alternator is lower than the load voltage, and a battery that serves as the power supply source for the load when the generated voltage of the alternator is higher than the battery voltage. In an engine equipped with an engine-driven alternator serving as a power supply source, a load input detection means for detecting that an electrical load is input; an engine control means that performs an increase correction of the corresponding engine intake air amount; a field current control means that increases and controls the field current of the alternator in accordance with the load current value required to drive the input electrical load; and the load input. The field current control is activated when the detection means detects a load input, and the field current is controlled within a predetermined period of time until the engine output reaches a value that can maintain the drive of the input electrical load due to an increase in the engine intake air amount by the engine control means. and field current adjusting means for fixing the control value of the field current controlling means so as to maintain the value of the field current controlled by the means at a predetermined value before the electrical load is input. It is characterized by:

Therefore, according to the present invention, even during idling operation, it is possible to operate the electrical load at the same time as the electrical load is input, and the engine corrects the intake air amount accordingly. On the other hand, the field current is held at the value before the load input until the engine side takes measures against the electrical load. Therefore, even if an electrical load such as a headlight or a power seat motor is applied during idling, the alternator itself will not cause a drop in engine speed, and the engine speed will not drop when the load is input. . Also,
When the field current is finally applied in accordance with the load current value, the engine side has already taken sufficient measures, so the drop in engine speed in that case can be suppressed to a minimum, and when idling Problems such as rotational problems and engine stalling can be prevented.

[Brief explanation of drawings]

FIG. 1 is a control circuit diagram of main parts of an engine rotation speed control device according to a first embodiment of the present invention, and a second embodiment of the present invention is shown in FIG.
The figure is a system diagram showing the overall configuration of the control circuit of the engine rotation speed control device in the above embodiment;
FIG. 3 is a time chart of the signals of the main parts of the control circuit shown in FIG. 1, and FIG. 5A and 5B are flowcharts for explaining the control operation of the control circuit shown in FIG. 4, and FIG. 6 is a time chart of signals of the main parts of the control circuit shown in FIG. 4. 1...Engine, 16...Alternator, 17
... Engine electronic control device, 20 ... Load input detection means, 21 ... Battery, 22 ... Electric load, 24 ... Load correction circuit, 28 ... Engine speed control circuit, 31 ... Field current adjustment means , 32, 38... monostable multivibrator circuit, 35... field coil, Q ₁ ... transistor.

Claims (1)

[Claims] 1. An engine equipped with a battery that serves as a power supply source for the load when the generated voltage of the alternator is lower than the load voltage, and an engine-driven alternator that serves as the power supply source for the load when the generated voltage is higher than the battery voltage. In particular, a load input detection means for detecting that an electrical load is input, and an engine control means for correcting an increase in the engine intake amount corresponding to the load amount of the electrical load when the electrical load is input. , field current control means for increasing and controlling the field current of the alternator in accordance with the input load current value required to drive the electrical load; and the engine control means, which operates when the load input detection means detects a load input. The field current value controlled by the field current control means remains unchanged for a predetermined period of time until the engine output reaches an output value that can maintain the driving state of the input electrical load due to an increase in the engine intake air amount. An engine rotation speed control device comprising field current adjusting means for fixing a control value of the field current controlling means so as to maintain it at a predetermined value before an electrical load is input.