JP2527727B2 - Internal combustion engine speed control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides an intake air adjustment using a loop for adjusting an intake air amount to a target value during no-load operation and a loop for adjusting a rotation speed to a target value in combination. While speeding up the speed adjustment operation,
The present invention relates to a rotation speed control device for an internal combustion engine that suppresses fluctuations in rotation speed after shifting to a load operating state.

[Conventional technology]

2. Description of the Related Art Conventionally, constant value control of the unloaded engine speed of an internal combustion engine has been performed to a predetermined engine speed. The purpose of this rotation speed control is to set the no-load rotation speed low so as to suppress fuel consumption when there is no load as much as possible, and to suppress rotation speed fluctuations due to external disturbances. Sex is required.

The factors that change the rotational speed are roughly classified into the primary factor due to the fluctuation of the no-load loss of the engine itself and the fluctuation of the thermal efficiency of the engine, and the adjustment gain inherent in the intake adjustment means used to adjust the rotational speed fluctuation due to this primary factor. It is classified as a secondary factor due to fluctuations in the air temperature and fluctuations in the density of the air that is the intake source.

Therefore, as seen in Japanese Patent Laid-Open No. 59-162340, an adjustment signal based on the deviation from the target intake air amount or the intake pipe pressure in accordance with the adjustment signal based on the deviation between the target value and the actual value of the rotational speed. There is a method of controlling the rotation speed to a target value by controlling the intake air adjusting means in accordance with the above.

According to this method, the adjustment signal (rotation speed adjustment signal) based on the deviation between the target value and the actual value of the rotation speed responds to the primary cause of the rotation fluctuation, and corresponds to the secondary factor. Is responsive to an adjustment signal (intake adjustment signal) based on the target value and the actual value of the intake air amount or intake pipe pressure, so it is possible to adjust the rotation fluctuation with high accuracy and speed, rather than controlling the feedback control only by the rotation speed. It is self-evident.

[Problems to be solved by the invention]

As described above, the conventional example shown in the above publication shows the intake air amount adjustment loop for the purpose of self-correcting the error in the rotation speed control means itself.

However, the above-mentioned conventional example as a rotation speed control device has the following practical problems. That is, in the no-load state, the rotation speed is controlled to the target value, but when the throttle valve is slightly opened and the engine is in the load state, the primary factor and the secondary factor are adjusted if the adjustment becomes inoperative. As a result, the intake air amount of the engine suddenly changes discontinuously, causing an abnormal decrease in rotation or increase in rotation, which significantly impairs drivability.

In particular, with respect to secondary factors, there is a large change over time due to initial variations and clogging of the control means, which is a problem that cannot be ignored.

The present invention has been made to solve such a problem, and an object of the present invention is to obtain an engine speed control device for an internal combustion engine capable of preventing fluctuations in engine speed during transition from an unloaded state to a loaded state. To do.

[Means for solving problems]

The engine speed control device for an internal combustion engine according to the present invention is arranged in an intake passage of the engine, and a rotation speed regulator that generates a target intake air amount of the engine in relation to a deviation between the engine speed and the target rotation speed. An intake air amount sensor that generates an electrical output corresponding to the intake air amount of the engine, an intake air regulator that generates a control signal in relation to the deviation between the output of the intake air amount sensor and the target intake air amount, and the engine in response to the control signal Intake control means for increasing / decreasing the intake air amount, load state detecting means for detecting the no-load operating state and load operating state of the engine, and a response signal to the detection signal of the load state detecting means in response to the engine's no-load operation. Switching means for operating the rotation speed regulator and the intake air regulator to match the rotation speed with the target rotation speed and stopping the operation of the rotation speed regulator and the intake air regulator when the engine is in a load state, and the engine no-load Destroying control signals when driving A memory for holding control signal during load operation proceeds updates stored and institutions provided, intake air control means, during the load operation of the engine, is intended to be actuated by a control signal stored in the memory.

[Action]

In the present invention, the engine speed regulator and the intake regulator are operated when the engine is unloaded, and the final value or the average value of the control signal from the intake regulator when the engine is unloaded is held in the memory, and the engine load condition is set. The values held in the memory by stopping the operation of the rotation speed adjuster and the intake air adjuster are applied as a signal for operating the intake control means in the load state.

〔Example〕

An embodiment of a rotation speed control device for an internal combustion engine according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of one embodiment. In FIG. 1,
Reference numeral 1 denotes an internal combustion engine, and an intake pipe 2 is connected to the internal combustion engine 1.

A throttle valve 3 is arranged at a predetermined position of the intake pipe 2. The throttle valve 3 controls the rotational speed according to the load. Bypass passages 91 and 92 are provided in the intake pipe 2 before and after the throttle valve 3.

A solenoid valve 8 having a linear characteristic is arranged as an intake control valve between the bypass passages 91 and 92. The solenoid valve 8 is driven and controlled by the output of the driving device 7.

On the other hand, the internal combustion engine 1 is provided with a gear 41. The gear 41 is adapted to interlock with the rotation of the internal combustion engine 1. The rotation of the gear 41 is detected by the rotation speed sensor 42. The rotation speed sensor 42 detects the rotation of the gear 41 and outputs the engine rotation speed ne to the error amplifier 61.

The output nT of the target speed generator 5 is also input to the error amplifier 61, and the error amplifier 61 outputs an error Δ between the output ne of the speed sensor 42 and the output nT of the target speed generator 5.
n is calculated and output to the rotation speed adjuster 62.

The target speed generator 5 generates a target value of the target no-load speed corresponding to various conditions such as the engine temperature, and the speed regulator 62 receives the output of the error amplifier 61. , A rotation speed adjustment signal is generated in a direction to eliminate the error Δn by proportional, integral or differential operation.

The output of the rotation speed adjuster 62 is sent to the limiter 12 via the memory 171. This limiter 12
Is to limit the output of the rotation speed adjuster 62 to a predetermined value or less.

The output of the limiter 12 becomes the target intake air amount QT of the engine. The target intake air amount QT is sent to the error amplifier 111. The error amplifier 111 includes a hot-wire intake air amount sensor 10
The intake air amount Qe from is also input.

The hot-wire intake air amount sensor 10 is provided in the intake pipe 2,
Responsiveness is good. With respect to the intake air amount Qe output from the hot-wire intake air amount sensor 10 and the target intake air amount QT output from the limiter 12, an error amplifier 111 calculates an error ΔQ and outputs it to the intake air regulator 112. There is.

The intake air regulator 112 receives the error ΔQ and generates an intake air adjustment signal in a direction to eliminate the error ΔQ by proportional, integral or differential operation, and the limiter 13 is supplied via the memory 172.
It is designed to output to.

The limiter 13 adjusts the output of the intake air regulator 112 to a predetermined value or less. The output of the limiter 13 is sent to the drive unit 7. The drive device 7 receives the output of the limiter 13 and sends a drive signal to the solenoid valve 8,
The opening area of the solenoid valve 8 is controlled to be increased or decreased by this drive signal.

Further, the unloaded switch 15 is interlocked with the throttle valve 3, and the switches 161 and 162 are controlled by the output of the unloaded switch 15.
The output of 62 controls the rotation speed regulator 62 and the intake air regulator 112, respectively.

Next, the operation of the rotation speed control device for an internal combustion engine of the present invention configured as described above will be described. No load switch
When the no-load condition of the engine is detected by 15, the switching device 16
1 and 162 control the rotation speed regulator 62 and the intake air regulator 112 to the operating state.

On the other hand, the gear 41 rotates in conjunction with the rotation of the internal combustion engine,
The rotation sensor 42 detects the rotation of the gear 41,
Output ne to the error amplifier 61. The error amplifier 61 calculates an error Δn with the output nT of the target rotation speed generator 5, that is, a rotation speed error Δn. The rotation speed regulator 62 is actuated by the rotation speed error Δn to generate an output.

The rotation speed adjuster 62 generates a target intake air amount of the internal combustion engine 1 in association with the rotation speed of the engine 1 and the target rotation speed. The output of the rotation speed adjuster 62 is output from the error amplifier 61. Since the output error Δn is generated in the direction of decreasing, it is settled when the error Δn of the rotation speed becomes minimum. Speed regulator
The output of 62 is input to the memory 171 every moment.

The output of the memory 171 is given to the limiter 12 every second. The characteristic of the limiter 12 is that the input X is
In the range of Xmin <X <Xmax, the output Y proportional to the input X is generated, and the purpose is to limit the excessive output.

The output of the limiter 12 is used as the target value QT of the intake air amount of the engine 1 and sent to the error amplifier 111. This error amplifier 1
The output Qe of the hot-wire intake air amount sensor 10 is also input to 11.
This hot-wire intake air amount sensor 10 has good responsiveness, and the internal combustion engine 1
The electric output corresponding to the intake air amount is generated.

The error amplifier 111 obtains an error ΔQ between the output Qe and the target value QT of the intake air amount and outputs it to the intake air regulator 112. Due to the error ΔQ in the intake air amount, the intake air regulator 112 operates to generate an output.

This output is a duty signal related to the intake air amount Qe output from the hot-wire intake air amount sensor 10 and the target intake air amount QT.

Since the output of the intake air regulator 112 is generated in the direction in which the error ΔQ decreases, it is settled when the error ΔQ becomes minimum. The output of the intake air regulator 112 is input to the memory 172 every moment. The output of the memory 172 is given to the tick limiter 13. The characteristics of the limiter 13 are similar to those of the limiter 12. This limiter
The output of 13 is converted into an electric signal by the driving device 7.

This electric signal is sent to the solenoid valve 8 having a linear characteristic. The solenoid valve 8 is for obtaining an intake air amount adjusting loop together with the hot-wire intake air amount sensor 10 having good responsiveness.

An electric signal output from the drive device 7 causes the solenoid valve 8 to operate so as to have an opening area corresponding to the electric signal, and the valve position changes in proportion to the input voltage.

In this way, by opening the solenoid valve 8 in response to the electric signal, the flow rate of air taken into the intake pipe 2 flows through the bypass passages 91 and 92, and the intake air amount of the internal combustion engine 1 increases or decreases.

Thus, the rotation speed of the internal combustion engine 1 is settled at the target value, and at this time, the intake air amount is also settled at the target value. The intake adjustment signal in this settling state adjusts the error ΔQ to a minimum.

This is due to variations in the amount of leaked air at the unloaded position of the throttle valve 3, characteristic fluctuations of the solenoid valve 8 due to initial characteristic error and temperature, power supply voltage dependency of the drive unit 7, or gain dependency due to atmospheric density, etc. This is because the intake adjustment signal adjusts the error inherent in each component for adjusting the.

The limiter 13 has an extremely limited value corresponding to a value obtained by substantially accumulating the errors inherent in the respective components for adjusting the intake air amount. Therefore, if the hot-wire intake air amount sensor 10 fails and the intake air amount Qe is no longer returned, even if the intake air adjustment signal diverges, the adjustment is limited by the limiter 12 and the intake air amount diverges. As a result, engine speed divergence (runaway or stop) is prevented.

Next, the rotation speed adjustment signal adjusts the error Δn to a minimum,
To make the engine speed ne approximately match the target speed nT,
The target intake air amount QT is being adjusted. This is because the rotation speed adjustment signal adjusts the load fluctuations due to various components such as lamps and motors, as seen in internal combustion engines for automobiles, etc. Is.

Further, the limiter 12 is set with an appropriate limit value corresponding to a value obtained by substantially accumulating errors due to the loss and load fluctuation of each part of the engine. Therefore, when the rotation speed sensor 42 or the like fails and the rotation speed is no longer fed back, the limiter 12 limits the adjustment even if the rotation speed adjustment signal diverges.
Since the target value of the intake air amount does not diverge, the engine speed is prevented from diverging.

Next, when the throttle valve 3 is opened and the engine is in a loaded state, the unloaded switch 15 detects this, and the switching devices 161 and 162.
Operates to stop the operation of the rotation speed adjuster 62 and the intake air adjuster 112.

Therefore, the outputs of the rotation speed regulator 62 and the intake regulator 112 stored in the memories 171 and 172, that is, the adjustment signals are held at the final values when there is no load, and the solenoid valve 8 is controlled based on these values. To be done.

Since the held value is a value corresponding to the fluctuation of the rotational speed due to various factors, the control state of the solenoid valve 8 at the time of shifting from the no-load state to the load state does not suddenly change.

As described above, when both the rotation speed feedback control and the intake air amount feedback control are used in combination, the intake air amount feedback control amount has an error specific to the engine (such as clogging of the intake air control passage) and the atmospheric environment (atmospheric pressure, etc.). The effect of is reflected, and an error that does not change within a short operating time (about 1 hour) is reflected. Therefore, it is of great significance to reflect the intake air amount feedback control amount when no load is applied.

In the embodiment shown in FIG. 1 described above, the adjustment signal is generated only on the basis of the difference between the target value and the actual value. However, in the term proportional to the target value and the difference between the target value and the actual value, It is also possible to generate an adjustment signal by combining with the term based.

Further, in order to further enhance the effect of the present invention, it is preferable that the adjustment speed of the intake air regulator 112 is faster than that of the rotation speed regulator 62, so that the intake air regulator 112 and the rotation speed regulator 6 are
It is preferable to set the proportional, integral or derivative adjustment gain of 2 higher than that of the former.

Furthermore, although the hot wire type is used as the intake air amount sensor in the embodiment of FIG. 1, other types of sensors can be applied. Similarly, as the intake adjustment control means, the solenoid valve 8
Alternatively, other types of actuators can be applied.

Further, although the example in which the intake air amount is controlled to be increased / decreased by the bypass passage has been shown, the control means of the system of directly opening / closing the throttle valve can be applied.

Next, as the no-load detection means, the no-load switch 15 is applied, but it is possible to perform the same control even if the no-load is detected by other various sensors such as the throttle valve opening sensor. is there.

Two switching devices 161 and 162 are provided corresponding to each of the rotation speed adjuster 62 and the intake air adjuster 112, but it is also possible to share one by sharing them.

Further, although the memories 171 and 172 of the embodiment hold the final value of the adjustment signal at the time of no load, as a method of holding an average value corresponding to an appropriate time interval at the time of no load, variation in the held value is suppressed. It is also possible.

Although the two memories 171 and 172 corresponding to the rotation speed adjuster 62 and the intake air adjuster 112, respectively, are provided, at least the memory 112 should be provided because the intake adjustment control signal is used during load operation. Good.

〔The invention's effect〕

As described above, the present invention provides a rotation speed regulator that generates a target intake air amount of an engine in relation to a deviation between the engine speed and a target rotation speed, and an intake air amount of the engine that is arranged in an intake passage of the engine. An intake air amount sensor that generates a corresponding electrical output, an intake air regulator that generates a control signal in relation to the deviation between the output of the intake air amount sensor and the target intake air amount, and the intake air amount of the engine is increased or decreased in response to the control signal. Intake control means for controlling, and a load state detecting means for detecting a no-load operating state and a load operating state of the engine,
In response to the detection signal of the load state detection means, when the engine is in the load state when the engine speed regulator and the intake air regulator are operated in order to match the engine speed with the target engine speed during no-load operation of the engine. A switching means for stopping the operation of the rotation speed regulator and the intake air regulator, and a memory for sequentially updating and storing the control signal at the time of no-load operation of the engine and holding the control signal at the time of load operation of the engine are provided. Since the intake control means is operated by the control signal stored in the memory during operation, the adjustment operation in the no-load operation state can be speeded up, and the engine speed and the intake air amount during the no-load of the engine can be adjusted. A memory for holding the quantity is provided, and the value holding that state is applied in the load state to control the intake control means, so that the transition from the no-load state to the load state is performed. And sudden change in the intake air amount is prevented, it does not occur abnormal increase or were One had been reduced inconvenience speed.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of a rotation speed control device for an internal combustion engine of the present invention, and FIG. 2 is a diagram showing an example of a characteristic of a limiter in the rotation speed control device for an internal combustion engine. 1 ... Internal combustion engine, 2 ... Intake pipe, 3 ... Slot valve,
5 ... Target speed generator, 7 ... Drive device, 8 ... Solenoid valve, 10 ... Hot wire type air intake sensor, 12,13 ... Limiter, 15 ... No load switch, 62 ... Rotation speed adjustment Bowl, 11
2 …… Intake regulator, 61,111 …… Error amplifier, 161,162 ……
Switch, 171, 172 ... Memory.

Claims (1)

(57) [Claims] 1. A rotation speed regulator that generates a target intake air amount of the engine in relation to a deviation between the engine speed and a target rotation speed, and an intake air amount of the engine that is disposed in an intake passage of the engine. An intake air amount sensor that generates a corresponding electric output, an intake air regulator that generates a control signal in association with a deviation between the output of the intake air amount sensor and the target intake air amount, and an intake air regulator of the engine in response to the control signal. Intake control means for increasing / decreasing the intake air amount, load state detecting means for detecting a no-load operating state and a load operating state of the engine, and a detection signal of the load state detecting means in response to the no-load operation of the engine. The rotation speed regulator and the intake air regulator are operated to match the rotation speed of the engine with the target rotation speed, and the rotation speed regulator and the intake air regulator are stopped when the engine is loaded. Cut off Means, and a memory for sequentially updating and storing the control signal during no-load operation of the engine and holding the control signal during a load operation transition of the engine, the intake control means, during a load operation of the engine ,
An engine speed control device for an internal combustion engine, which is operated by the control signal stored in the memory.