JPH0457856B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic no-load rotation speed control device for an internal combustion engine (particularly an automobile engine).

Recently, in order to improve the exhaust purification performance, fuel efficiency, etc. of automobiles, it has become necessary to precisely control the rotational speed of the engine when it is under no load (idling). Therefore, an arithmetic circuit using a microcomputer or the like is installed, and the arithmetic circuit compares the actual no-load rotation speed with a value stored in advance in the memory of the arithmetic circuit, and the actual rotation speed is memorized. If it exceeds the value, outputs a signal to reduce the air supply amount,
In the opposite case, a method has been developed in which a signal to increase the rotational speed is outputted, and the air supply amount is controlled in accordance with the signal, thereby controlling the rotational speed in a feedback manner. Note that since the amount of fuel supplied to the engine (for example, the amount of fuel injection) is determined according to the amount of air supplied, the rotation speed can be controlled by controlling the amount of air supplied.

However, in the conventional feedback control method as described above,
There is a problem in that the response to small load fluctuations when no load is applied is slow.

In other words, in the case of a car, even when there is no load (when the vehicle is not being driven), the shift position of the automatic transmission (the load changes between the neutral position and the drive position), the compressor for the cooler (car cooler compressor), etc. Some load fluctuations occur depending on whether or not auxiliary equipment such as In the conventional feedback control method, the control amount changes only when the rotational speed changes due to load fluctuations, so the deviation from the target rotational speed until the rotational speed stabilizes is large and the response is slow. Furthermore, if the gain of feedback control is increased in order to speed up the response, there are problems such as unstable control.

The present invention detects minute load fluctuations and predicts rotation speed changes resulting from them, and adds predictive control to conventional feedback control to automatically control rotation speed during no-load conditions and suppress rotation speed fluctuations during minute load fluctuations. The purpose is to provide a control device.

The present invention will be explained in detail below based on the drawings.

FIG. 1 is a block diagram illustrating the functionality of the present invention.

In FIG. 1, reference numeral 100 indicates a rotation sensor for detecting the rotation speed of the engine, such as rotation sensor 2 shown in FIG. 2, which will be described later. Further, 101 is a sensor for detecting engine operating variables (such as engine temperature) other than the rotational speed, such as the temperature sensor 1 shown in FIG. 2, which will be described later.
Reference numeral 102 denotes a detection means for detecting changes in the shift position of the automatic transmission and the presence or absence of operation of auxiliary equipment (such as a car cooler), which may cause minute load fluctuations in the engine. For example, the cooler operation sensor 3 shown in FIG. , the shift position sensor 4, etc.

The deviation detection means 103 detects the actual rotation speed detected by the rotation sensor 100 and the target rotation speed constant means 107.
The deviation from the target rotation speed given by (details will be described later) is detected.

The control means 104 outputs a control amount according to the above deviation.

When the detection means 102 detects a cause of variation, the correction means 105 reads a correction control amount corresponding to the cause of variation from the storage means 108 (details will be described later),
A value obtained by adding the corrected control amount to the control amount of the control means 104 is output.

The target rotation speed setting means 107 normally sets the target rotation speed according to the output of the sensor 101, for example, the engine temperature, but when the detection means 102 detects the occurrence of a cause of variation, the target rotation speed is set according to the cause of the variation. The number is read from the storage means 108 and set.

The storage means 108 stores in advance a target rotational speed corresponding to the cause of variation and a correction control amount that increases or decreases by a value corresponding to the amount of load variation caused by the cause of variation.

Further, the throttle fully closed detection means 110 detects that the throttle valve opening of the internal combustion engine is fully closed (so-called idle opening), and for example, the throttle valve opening sensor 6 shown in FIG. It can be used.

Further, the stop detection means 111 detects that the vehicle is stopped, and for example, the second
The vehicle speed sensor 5 shown in the figure can be used.

Further, the neutral detection means 112 detects that the transmission is in the neutral position, and for example, the shift position sensor 4 shown in FIG. 2, which will be described later, can be used. Note that the throttle fully closed detection means 110 is always necessary, but the stop detection means 11
1 and the neutral detection means 112, either one or both may be provided.

Next, the switching means 109 determines whether the throttle valve is fully closed based on the signals from the throttle fully closed detecting means 110, the stop detecting means 111, and the neutral detecting means 112 (at least one of the stop detecting means 111 and the neutral detecting means 112). When the engine is closed and the vehicle is stopped or the transmission is in the neutral position, it is determined that the internal combustion engine is under no load, and the air supply valve 106 (e.g. The air supply valve 14) shown in Fig. 2 below is controlled to perform feedback control, and in other cases, it is determined that it is not a no-load condition and the above-mentioned feedback control is stopped, and the control is determined according to the engine temperature. The air supply valve 106 is controlled according to the amount 113.

Note that the deviation detection means 103 and the control means 1 described above
04, correction means 105, target rotation speed setting means 10
7. The storage means 108 and the switching means 109 are comprised of, for example, the microcomputer 8 shown in FIG. 2, which will be described later.

With the above configuration, when a minute load fluctuation occurs, the control amount is changed by the sum of the correction control amount that has a value corresponding to the cause of the fluctuation, so the amount of load fluctuation that differs depending on the cause of the fluctuation is changed. It is possible to perform corrections that are well suited to the load fluctuations, and even when a plurality of fluctuation causes occur simultaneously, it is possible to effectively compensate for load fluctuations caused by them. In addition, since it is configured to perform corrections corresponding to increases and decreases in load, accurate rotational speed control can always be performed whether the load increases or decreases.

Additionally, when the vehicle is running at deceleration (the throttle valve is closed while the vehicle is running), the engine is driven by the vehicle in a so-called engine braking state, and the actual rotation speed is higher than the target rotation speed. Since the air supply amount is always large, if feedback control is performed, the air supply amount is controlled to the minimum, and as a result, the air supply amount may decrease too much and cause engine stall or rotational fluctuation when idling after deceleration driving is completed. However, in the present invention, By configuring the feedback control to be performed when the throttle valve is fully closed and the vehicle is stopped or the transmission is in the neutral position, the feedback control is performed when the vehicle is decelerating. Since this reliably prevents the above problems from occurring, it is possible to prevent the above problems from occurring.

Hereinafter, the present invention will be explained based on Examples.

FIG. 2 is a diagram showing an embodiment of the automatic control device of the present invention, and FIG. 3 is a flowchart of control.

In FIG. 2, 1 is a temperature sensor that detects the engine temperature and outputs a temperature signal _S1 . As the temperature sensor 1, for example, cooling water temperature, combustion chamber wall temperature,
A thermistor or the like that detects lubricating oil temperature, exhaust gas temperature, engine outer wall temperature, etc. can be used.
Further, 2 is a rotation sensor that detects the engine rotation speed. The rotation sensor 2 includes, for example, a magnetic gear that rotates in synchronization with the crankshaft, and a magnetic detector that outputs a pulse every time the teeth of the gear pass, and outputs a pulse signal with a frequency proportional to the number of rotations. A device that outputs can be used.

Reference numeral 3 designates a cooler operation sensor, which is, for example, a switch that is turned on when the compressor of the cooler is activated. Reference numeral 4 designates a shift position sensor, which is, for example, a switch that is turned on when the shift position of the transmission is in the drive position (including forward and reverse) and turned off when it is in other positions (neutral, parking, etc.). Further, 5 is a vehicle speed sensor that determines whether the vehicle is running or stopped, and is, for example, a switch that is turned on when the vehicle is stopped and turned off when it is running.
Reference numeral 6 denotes a throttle opening sensor, which is a switch that is turned on when the throttle valve (or accelerator pedal) is in a fully closed position (during idling) and turned off at other times.

Further, the A/D converter 7 converts the analog temperature signal _S1 output from the temperature sensor 1 into a digital temperature signal _S2 .

8 is a microcomputer (hereinafter μ-
9 is an input/output device, 10 is a central processing unit (hereinafter abbreviated as CPU), and 11 is a memory.

The μ-COM 8 receives signals from the sensors 1 to 6 described above via the input/output device 9, and outputs a control signal _S3 corresponding to their states.

On the other hand, the upstream and downstream parts of the throttle valve 13 provided in the intake pipe 12 of the engine are the air supply valve 1.
They are connected by a bypass via 4. Also, solenoid valve 1
8 intermittently disconnects the atmospheric pipe 19 and the negative pressure pipe 20 according to the opening and closing of the valve. Therefore, the air supply valve 1 connected between the negative pressure pipe 20 and the solenoid valve 18
The pressure in the air chamber 15 of No. 4 changes depending on the opening/closing time of the solenoid valve 18 (the longer the opening time is, the higher the pressure is; the shorter the opening time is, the lower the pressure is).
and the valve 17 connected thereto move up and down, thereby changing the amount of air supplied to the engine via the air supply valve 14. Therefore, by changing the duty ratio of the pulse signal (hereinafter referred to as control pulse) that controls the solenoid valve 18, the air supply amount can be freely controlled. If the aforementioned control signal _S3 is used as this control pulse, the air supply amount (and therefore the rotational speed) during no-load conditions can be controlled by μ-COM8.

Note that the memory 11 in FIG. 2 includes various different memories depending on the contents to be stored, namely (a) memory for target rotational speed data for engine temperature, (b) memory for target rotational speed, c) memory for engine temperature, and (d) memory for cooling. Contains memory for machine operating status, E memory for control pulse width, F memory for control pulse width for engine temperature, memory for current rotation speed, memory for total number of control cycles, memory for re-shift position, etc. .

Next, the contents of calculations in μ-COM 8 will be explained with reference to the flowchart shown in FIG. In this flowchart, the flowchart signals (A) to (R) marked on the left are one cycle of control, and control is performed, for example, one cycle per revolution in synchronization with the rotation of the engine.

When the engine starts and the calculation of μ-COM 8 starts, the temperature signal S ₂ is first input (A), and this temperature signal S ₂ is stored in the memory 11 (a memory for target rotation speed data for engine temperature). The target rotation speed N _M of the engine is calculated from the stored target rotation speed data corresponding to each temperature, and it is stored in the memory 11 along with the temperature value (N _M is the memory for the target rotation speed, temperature value is stored in the engine temperature memory) (B). Note that the idling speed takes different values depending on the engine temperature; for example, when warming up immediately after starting, the speed is set to a higher value than during normal times, and as the temperature rises, it gradually approaches the normal value. It's becoming like that.

Next, check the operation of the chiller compressor.
(C). While the compressor is operating, the load on the engine increases somewhat, and in order to fully utilize the compression ability of the compressor, it is necessary to increase the no-load rotational speed by a certain value. Therefore, when the cooler operation sensor 3 indicates "operation", the value of the target rotation speed N _M stored in the memory 11 (above-mentioned target rotation speed memory) is increased by a certain value. The above constant value uses a value stored in the memory in advance. Furthermore, since this alone will slow down the response, it is necessary to change the control amount in advance by an amount commensurate with the load fluctuation (predictive control). Therefore, judging from the signal of the cooler operation sensor 3 and the signal of the cooler operation sensor 3 of the previous calculation cycle stored in the memory 11 (secondary cooler operation state memory),
When switching from "stop" to "operation", the control pulse width calculated up to the previous cycle and stored in the memory 11 (E control pulse width memory) is increased by a certain value, and conversely, from "operation" to " When switching to "Stop", the same value is decreased. Also memory 11
The information stored in (e) control pulse width memory is updated at this point (D), (E). Note that the above-mentioned constant value uses a value stored in advance in the memory.

Next, it is determined whether the engine is in a no-load state based on the signals from the shift position sensor 4, vehicle speed sensor 5, and throttle opening sensor 6 (F), (G), (H), (I),
(J).

First, when the throttle opening sensor 6 indicates "open," and even when the throttle opening sensor 6 indicates "fully closed," the shift position sensor 4 indicates the "drive position," and the vehicle speed sensor 5 indicates "driving." If it shows "medium", it is judged that it is not in a no-load state, and the engine temperature at that time stored in the memory 11 (c memory for engine temperature) and the memory 11 (f memory for control pulse width for engine temperature) are stored. ) The control pulse width initial value is calculated from the control pulse data corresponding to each engine temperature stored in ), and the value is stored again in the memory 11 (control pulse width memory) as the control pulse width.

Furthermore, when the throttle opening sensor 6 indicates "fully closed" and the shift position sensor 4 indicates "drive position", the vehicle speed sensor 5 indicates "stopped".
, and when the throttle opening sensor 6 indicates "fully closed" and the shift position sensor 4 indicates "neutral position", it is determined that there is no load. signal changes from “drive position” to “neutral position”,
Or vice versa, the load changes somewhat due to the change in resistance within the transmission. Therefore, the control pulse width stored in the memory 11 (E memory for control pulse width) is set to the "neutral position".
When changing from to "drive position" (judged from the signal of the shift position sensor 4 of the previous calculation cycle stored in the re-shift position memory), it is increased by a certain amount, and in the opposite case, it is decreased by the same amount. (Memory 1
The determination is made from the signal of the shift position sensor 4 of the previous control cycle stored in No. 1 and the signal of the shift position sensor 4 of the current control cycle. ) to perform predictive control. The above-mentioned fixed amount uses a value stored in the memory in advance.

Further, when the throttle opening sensor 6 indicates "fully open", when the vehicle speed sensor 5 indicates "stopping" even when the shift position sensor 4 indicates "drive position", and when the throttle opening sensor 6 indicates "stopping",
When the shift position sensor 4 indicates "fully closed" and the shift position sensor 4 indicates "neutral position," it is determined that there is no load, and the control pulse width is determined by performing feedback control in the following order.

First, the data of the rotation speed N given from the rotation sensor 2 is stored in the memory 11 (memory for the current rotation speed).
Store in (K).

Next, the target rotation speed N _M already stored in the memory 11 (memory for target rotation speed data for the engine temperature) and the actual rotation speed N stored in the memory 11 (memory for the current rotation speed data) It is determined whether there is a significant difference, that is, whether the deviation between N _M and N is greater than or equal to a predetermined value N ₀ (L).
If there is no significant difference, the control pulse width is maintained at the previous value and the opening degree of the air supply valve is fixed. If there is a significant difference, and the actual rotation speed N is larger, increase the value of the cumulative number of control cycles in the memory 11 (memory for cumulative number of control cycles) by 1 (M), (O) . This increased value is K (usually 5 to 10
If the total number of control cycles reaches 0, the control pulse width is reduced by a certain amount and stored in the memory 11 (control pulse width memory) (P).

Conversely, if the actual rotation speed N is smaller, the cumulative number of control cycles is reduced by 1, and when the reduced value reaches -K, the cumulative number of control cycles is returned to 0, and the control pulse width is reduced by a certain amount. Increase memory 1
1 (E control pulse width memory)
(M), (N), (Q).

With the above operation, the control pulse width is corrected if the actual rotation speed is higher or lower than the target rotation speed K times in a row (or every K rotations if the control cycle is synchronized with the rotation speed). Ru. In addition, if no-load operation is not performed, if there is no significant difference between the actual rotation speed and the target rotation speed, or if the magnitude relationship between the actual rotation speed and the target rotation speed is reversed, the cumulative control cycle will be 0. be returned.

Through the above calculations, the control pulse width is calculated and stored in the memory 11 (control pulse width memory) both in the case of no-load operation and in other cases. and a control signal with a pulse width corresponding to that value.
_S3 is output via the input/output device 9, and the solenoid valve 18
Sent to (R).

As described above, according to the control device of the present invention, minute load fluctuations are detected by the signals of the cooler operation sensor 3 and the shift position sensor 4, and predictive control corresponding to the load fluctuation is performed. control responsiveness improves.

FIG. 4 is a comparison diagram of responsiveness during load fluctuations.

In the figure, in the case of conventional feedback control only, if the load a changes at time _t1 , the rotational speed c changes, and control is performed only after that change is detected, and the air supply valve opening b changes. Therefore, as shown in the figure, the rotational speed c fluctuates greatly when the load fluctuates.

On the other hand, in the present invention, since the air supply valve opening degree d is changed by performing predictive control when the load fluctuates, fluctuations in the rotational speed e can be made extremely small.

As explained above, the present invention is configured to detect the cause of minute load fluctuations and add a correction control amount that increases or decreases by a value corresponding to the amount of load fluctuation caused by the cause of the fluctuations. It is possible to reduce the amount of deviation from the target rotational speed when a fluctuation occurs, and it is also possible to shorten the time until the rotational speed returns to the target rotational speed.

In addition, since the control amount is changed by the sum of the correction control amounts that have values corresponding to each cause of variation, it is possible to perform corrections that are well suited to load fluctuations that differ depending on the cause of variation, and also to compensate for multiple fluctuations. Even when the causes occur simultaneously, the load fluctuations caused by the causes can be effectively compensated for. In addition, since it is configured to perform corrections corresponding to increases and decreases in load, accurate rotational speed control can always be performed whether the load increases or decreases.

Further, by configuring the target rotation speed to be set according to the cause of variation, the rotation speed during no-load operation can be controlled to a desired value depending on the presence or absence of a minute load.

In addition, since the feedback control is performed when the throttle valve is fully closed and the vehicle is stopped or the transmission is in the neutral position, the feedback control is performed when the vehicle is decelerating. Since the feedback control is performed during deceleration driving, it is possible to prevent the air supply amount from decreasing too much and causing engine stalling or rotational fluctuation when idling after deceleration driving, etc. Many excellent effects can be obtained.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing the functions of the present invention, Figure 2 is a block diagram showing the functions of the present invention.
The figure is an embodiment of the present invention, FIG. 3 is a flow chart showing an embodiment of the calculation in the present invention, and
The figure is a comparison diagram of responsiveness during load fluctuations. Explanation of symbols, 1...Temperature sensor, 2...Rotation sensor, 3...Cooler operation sensor, 4...Shift position sensor, 5...Vehicle speed sensor, 6...Throttle opening sensor, 7...A-D converter, 8...Micro Computer, 9... Input/output device, 10... Central processing unit, 11
...memory, 12...intake pipe, 13...throttle valve,
14... Air supply valve, 15... Air chamber, 16... Diaphragm, 17... Valve, 18... Solenoid valve, 19... Atmospheric pipe, 20... Negative pressure pipe, 100... Rotation sensor, 101
...Sensor for detecting engine operating variables, 102...Detection means, 103...Difference detection means, 104...Control means, 105...Correction means, 106...Air supply valve, 1
07...Target rotation speed setting means, 108...Storage means,
109...Switching means, 110...Throttle fully closed detection means, 111...Stop detection means, 112...Neutral detection means, 113...Control amount determined according to engine temperature.

Claims (1)

[Claims] 1. Compare the actual rotation speed with a target rotation speed at no-load, which is preset according to the temperature of the internal combustion engine, etc., and make the actual rotation speed match the target rotation speed. In an automatic no-load rotation speed control device for an internal combustion engine that calculates a control amount and feedback-controls the opening degree of an air supply valve that adjusts the amount of air supplied to the internal combustion engine according to the control amount, Detection means for detecting at least two of the causes of minute load fluctuations assumed in advance, and a detection means for detecting at least two of the causes of minute load fluctuations, and a target rotation speed corresponding to each of the above fluctuation causes, and an increase/decrease by a value corresponding to the amount of load fluctuation caused by each of the fluctuation causes. a storage means for storing in advance a corrected control amount to be set; a deviation detection means for detecting a deviation between a target rotation speed and an actual rotation speed; control means that stops feedback control when the deviation is greater than a set value, performs feedback control and outputs a controlled amount according to the deviation; target rotation speed setting means for reading and setting the target rotation speed to a value corresponding to the cause of the variation; and when the detection means detects the occurrence of the cause of variation, reading out from the storage means a correction control amount corresponding to the cause of the variation. a correction means for adding the control amount to the control amount of the control means and outputting the result; a throttle fully closed detection means for detecting that the throttle valve opening of the internal combustion engine is fully open; and a throttle fully closed detection means for detecting that the vehicle is stopped. When the throttle valve is fully closed and the vehicle is stopped based on signals from at least one of the stop detection means and the neutral detection means for detecting that the transmission is in the neutral position, and each of the above means. Or, when the transmission is in the neutral position, it is determined that the internal combustion engine is under no load, and the air supply valve is controlled by the signal from the correction means to perform feedback control, and it is determined that the internal combustion engine is not under no load. An automatic no-load rotation speed control device for an internal combustion engine, comprising: a switching means for controlling the air supply valve with a control amount determined according to engine temperature when the air supply valve is in a controlled state;