JPS6263158A - Idling speed controller for engine - Google Patents

Abstract

PURPOSE:To prevent the reduction of the engine speed by setting the difference between the intake air quantity at that time point and the fundamental intake air quantity in feedback control as the feedback control quantity, when the engine is put into the idle speed region. CONSTITUTION:An intake air quantity adjusting means 1 adjusts the intake air quantity supplied into an engine. A feedback control means 2 feedback- controls the intake air quantity due to the means 1 so that the engine speed converges to a prescribed value in idle operation. Further, an intake air adding means 3 on start controls the means 1 so that a prescribed quantity of intake air is added on start, and the intake air quantity is gradually reduced through the lapse of time. In the above apparatus, when the engine is put into the idel speed region, the control of the intake air quantity is started by a means 2, having the difference between the intake air quantity at that time point and the fundamental take air quantity in feedback control as the feedback control quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine idle speed control device, and particularly to an engine idle speed control device that is equipped with a starting intake air adding means for adding a predetermined amount of intake air at starting. Related to numerical control devices.

(Prior art) In order to improve the fuel efficiency and exhaust performance of automobile engines, the amount of intake air is adjusted during idling operation, as disclosed in, for example, Japanese Patent Application Laid-Open No. 54-98413. Feedback the engine speed to the specified target speed! lit! In addition to such feedback control, in order to improve the startability of the engine, the basics of the feedback Add the specified intake air amount to the intake air amount and start! I7
In addition to setting the amount of intake air at 1:00, loop control may be performed while gradually reducing the added amount of intake air or the amount of intake air at startup as time passes. In that case, conventionally, when the intake air amount at startup is reduced to the basic intake air port (the intake air amount indicated by the symbol (B) in the figure) corresponding to the target rotation speed in feedback control, The system is configured to shift from the open-loop control to feedback control, and when the basic intake air amount accurately corresponds to the target rotation speed no shown in the figure (IV), the chain line in the figure (IV) As shown, the engine speed is converged to the target speed no at approximately the same time as the start time to of the feedback control. However, the above-mentioned basic intake air amount does not always correspond accurately to the target rotation speed no. because it is affected by changes in outside temperature and variations in engine performance.
is relatively smaller than the intake air amount corresponding to the target rotation speed no, the engine rotation speed reaches the target rotation speed no at the time of transition from open loop control to feedback control as shown in FIG. At the same time, when transitioning to feedback control [after 0 in the same figure (I
The feedback control amount must be continuously increased as shown by the symbol (C) in I), and the total intake air amount corresponds to the target-rotational speed no. shown by the symbol (D) in the same figure (III). It will take a relatively long time to reach the air volume. Therefore, as shown by the solid line in FIG. The stabilization of the engine rotational speed after starting is impaired, and furthermore, when the rotational speed drops sharply, the engine stalls.

(Object of the Invention) The present invention addresses the above-mentioned problems regarding engine idle speed control devices. In a configuration that performs open-loop control in which a predetermined amount of intake air is added at one time and the added intake air is gradually reduced over time, when the above-mentioned open-loop control is transitioned to feedback control during engine startup. To always start feedback control satisfactorily without being affected by variations in outside temperature or engine performance. The purpose of this is to improve the startability of the engine and to stabilize the engine speed by preventing the engine speed from dropping during the transition from startup to idling operation.

(Structure of the Invention) In order to achieve the above object, the engine idle speed control device according to the present invention is characterized by having the following structure.

That is, as shown in FIG. 1, in response to an intake air amount adjusting means 1 that adjusts the intake air port supplied to the engine and an idle region determination signal A indicating that the engine operating region is in the idle region, The intake air amount adjusting means 1 is arranged so that the actual engine speed converges to the idle target speed.
feedback control means 2 for feedback controlling the amount of intake air according to In a configuration including a starting intake air adding means 3 that gradually reduces the amount of intake air, the reduction of the intake air added by the starting intake air adding means 3 at the time of engine startup brings the operating range of the engine into an idle range. When the engine enters the engine, the feedback control means 2 starts controlling the intake air amount by using the difference between the intake air amount at that time and the basic intake air amount for the feedback control as a feedback control amount.

By the way, the feedback control means 2 adjusts the engine speed by adding or subtracting a feedback control amount (intake air amount) determined according to the deviation between the actual engine speed and the idle target speed to the basic intake air amount. According to the above configuration, the starting intake air adding means 3
The difference between the actual intake air amount supplied to the engine and the basic intake air amount when entering the idle area from the control area by the above feedback control amount, that is, when the engine speed drops to the idle target speed, is used as the feedback control amount. Control by the control means 2 is started.

Therefore, at the start of feedback control, the total of the basic intake air amount and feedback control ull, that is, the initial value of feedback control, accurately corresponds to the target idle rotation speed.

(Effects of the Invention) As described above, according to the engine idle speed control device according to the present invention, in addition to normal feedback control in the idle region, in order to reliably start the engine,
In a configuration that performs loop control while adding a predetermined amount of intake air at the time of starting and gradually reducing the added intake air, when the engine enters the idle region after starting, the actual intake air being supplied to the engine is Feedback control is started based on the difference between the air amount and the basic intake air amount for feedback control, so if the basic intake air amount is changed to a predetermined idle due to changes in outside temperature or variations in engine performance, etc. Even when the engine speed does not correspond exactly to the target engine speed, the feedback control is always started at an engine speed that is approximately equal to the target engine speed. This prevents the engine speed from dropping or becoming unstable at the start of feedback control, and also reliably prevents the engine from stalling, allowing the engine to smoothly transition from startup to idling operation.

(Example) Embodiments of the present invention shown in the figures will be described below.

As shown in FIG. 2, the combustion chamber 11 of the engine 10 includes:
An intake passage 14 and an exhaust passage 15 communicate with each other via intake and exhaust valves 12 and 13, and an air flow sensor 16 is connected to the intake passage 14 from the upstream side to detect the intake air sucked into the combustion chamber 11. , a throttle valve 17 that controls the intake air amount or engine output, and a fuel injection nozzle 18 that supplies fuel to the combustion chamber 11. Furthermore, the intake passage 14 is provided with a bypass passage 19 that communicates the upper and downstream sides of the throttle valve 17, and the intake passage 14 is provided with a bypass passage 19 through which air is supplied to the combustion chamber 11 through the passage 19 during idle. An electromagnetic control valve 20 is provided to adjust the amount of intake air.

On the other hand, this engine 10 is equipped with a control unit 21 that controls the electromagnetic control valve 20. The control unit 21 receives an engine rotation speed signal a output from an engine rotation sensor 22 that detects the rotation speed of the engine 10, and a throttle opening signal a output from a throttle opening sensor 23 that detects the opening degree of the throttle valve 17. It is determined whether the operating range of the engine 10 is in the idle range based on the engine speed signal C, and if the operating range is in the idle range, the idle control signal C is outputted to the control valve 20 and the bypass passage 19 is By adjusting the amount of intake air passing through the engine speed signal a
Feedback control is performed to converge the idle rotation speed indicated by to a predetermined target rotation speed. Further, this control unit 21 increases the intake air amount when the engine start signal d from the starter 24 that detects the start of the engine 10 is input, and gradually increases the intake air temperature by the amount of increase over time. 1 flit 1 control well 2 above to decrease
The starting control signal C' is output at 0. The control unit 21 sets the fuel injection amount based on the engine speed signal a and the intake flow rate signal e output from the air flow sensor 16, and also controls the fuel injection nozzle so as to achieve this injection amount. The idle control signal C or the starting control signal C' is corrected based on the load signal 0 from the load sensor 25 which outputs the fuel control signal `` to the fuel control signal 18 and also detects the operation of loads such as air conditioners and power steering.
By outputting this to the electromagnetic control valve 20, the intake air amount is corrected and controlled in accordance with the operation of the load.

In addition to the above-mentioned configuration, this control unit 21 also provides a starting control signal C to the electromagnetic control valve 20 when the engine 1 enters the idle region after starting.
When the increase in the intake air amount is gradually reduced by outputting ', and the engine rotation speed indicated by the engine rotation speed signal a falls to a predetermined target rotation speed, the intake air amount indicated by the starting control signal C' at that point in time is The feedback control is started using the difference between ff1 (duty ratio of the electromagnetic control valve 20) and a preset basic intake air amount as a feedback control amount.

Next, the operation of the control unit 21 will be explained according to the flowchart shown in FIG.

First, in step x1 in the flowchart, the control unit 21 detects the operating state of the engine 10 based on the engine rotational speed signal a, throttle opening signal, engine start signal d, etc., and in step x2, the control unit 21 detects the operating state of the engine 10. As a result of determining whether or not the engine has just started, if the engine has just started, step x3 is executed to set the intake air amount at startup ff1Q which is increased from the intake air amount at normal 111 aircraft time, After that, step x4~
Execute X6. In other words, by executing step x4, the starting intake air ff1 set in step x3 above is
The intake air (d) obtained by subtracting the predetermined intake air ffl and 6Q from Q is set as a new starting intake air ff1Q, and this starting air intake ff1Q is outputted to the electromagnetic control valve 20 as a starting control signal C', and step In Step 5, the actual engine rotation speed N is higher than the predetermined target rotation speed No (see Fig. 4 (IV)), and in step x6, the above-mentioned new starting intake air fiQ is set to the above-mentioned target rotation speed No. A predetermined basic intake IQO ((I) in the same figure) set to correspond to
If it is determined that the amount is higher than
The intake air amount obtained by subtracting a predetermined intake air m/JQ from Q is set as a new intake air faQ at startup. Then, until the actual engine speed N becomes lower than the target engine speed NO or the starting intake air ff1Q becomes lower than the predetermined basic intake air 2QO set to correspond to the target engine speed NO. By repeatedly executing the process of step x4 above, the intake air amount Q at the time of starting is gradually reduced as shown by the symbol (E) in FIG. 4(I), and this stepwise reduction is By outputting each starting intake air mQ to the electromagnetic control valve 20 as a starting control signal C' each time, the amount of intake air passing through the bypass passage 19 is gradually reduced.

As a result, as shown in the figure (IV), the engine speed N was effectively increased immediately after the start of the engine 10, ensuring the start of the engine 10, and the peak x1 shown in the figure was generated. The rear engine speed N is gradually reduced.

However, while the process of step x4 is being repeatedly executed, the engine speed N becomes equal to or less than the target engine speed NO, as shown by the symbol x2 in FIG. 4 (IV). If so, the control unit 21 executes steps x7 to x10. That is, the intake air ff1Q at the time of starting when the engine speed N is equal to or less than the target speed NO as described above, that is, Fig. 4 (I)
The starting intake air amount Q at the sign x 2′ shown in is set as the first coefficient , and after setting the difference between the first coefficient (See Figure 4 (If)). Here, the above-mentioned basic intake air amount QO is preset to correspond to the above-mentioned target rotation speed No. However, due to the influence of the outside temperature, variations in engine performance, degree of deterioration, etc. The basic intake air ff1Qo and the target rotational speed NO do not correspond accurately, which causes a difference as shown by the symbol Z in FIG. 4(I).

Next, the control unit 21 confirms that the operating range of the engine 10 has entered the idle range as the engine speed N has decreased to the target speed No as described above in step x11, and then performs step x12. X1
3 and calculate the actual rotation speed N of the engine 10 by the fourth coefficient
' and set the target rotational speed NO as the fifth coefficient Y', in step X14 this fourth coefficient
' is smaller than the fifth coefficient Y', and as a result, if the fourth coefficient X' is smaller, that is, if the actual rotation speed N of the engine 10 is smaller than the target rotation speed NO. Step x15 is executed, and the fourth coefficient X'
is larger, that is, when the actual rotation speed N of the engine 10 is larger than the target rotation speed No, step x16 is executed. That is, in step x15, the fourth
A control f;k corresponding to the deviation between the actual rotation speed N and the target rotation speed No.
By adding lUD1, a new feedback control lD+ is set, and similarly, in the above step x16, the control mAD1 corresponding to the deviation is subtracted from the feedback control 101 set to correspond to the difference 2. New feedback system tllllD
Set 1. Then, the control unit 21 executes step x17 to set the basic intake air amount QO as the basic control amount D2, and also performs step x18.
By executing this and adding this basic charge tllffiD2 and the feedback control 11Dt, the final control f
f1D is set, and this final control 10 is output as the idle control signal C to the electromagnetic control valve 20. Incidentally, while the operating state of the engine 10 is in the idle region, the processes of steps x11 to x1a are repeatedly executed. In this way, when the operating range of the engine 10 enters the idle range, the difference 2 between the actual intake air ff1Q and the basic intake air amount QO at the time of entry is set as the feedback control amount D1 as shown in FIG. 4 (IF). At the same time, the above-mentioned steps x11 to Xta are executed based on this feedback control ff1D1 and feedback control is started, so that the above-mentioned basic intake IQO is
Even when the predetermined target rotational speed NO does not correspond accurately due to the influence of outside temperature or variations in the performance of the engine 10, the bypass passage 19 as shown in FIG. 4 (III)
The total amount of intake air passing through the feedback tIII
Immediately after TO at the start of tIl, it becomes approximately equal to the intake IQ' which exactly corresponds to the target rotational speed No. Therefore, Fig. 4 (T
As shown in V), the engine speed N does not suddenly drop near the time TO at the start of the feedback control, but converges well to the target speed NO immediately after the time TO at the start of the feedback control, and the engine 10 A sudden change in the engine speed N after starting will reliably prevent engine stalling and the like.

Note that the control shown in the time chart of FIG. 4 is for the case where the preset basic intake air ff1Qo is less than the intake air ff1Q' that accurately corresponds to the target rotational speed NO, but on the contrary, If the basic intake air ff1Qo is greater than the intake mQ', the control unit 21 determines that the actual intake air ff1Q has become less than the basic intake mQO in step x6 in the flowchart, and then performs the same process as above. The processes of steps x7 to x18 will be executed, and therefore feedback control will be successfully started in this case as well.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing the basic concept of the present invention. Figures 2 to 4 show embodiments of the present invention, with Figure 2 being a control system diagram, Figure 3 being a flow chart showing the operation of the control unit, and Figures 4 (I), (II), (1 )
, (rV) are time charts of starting intake air volume,
They are a time chart of the feedback ilJm mother, a time chart of the total intake air amount, and a time chart of the engine rotation speed showing the action and effect. Also, Figure 5 (1)
. (II), (III), and (IV) are conventional time charts of the basic intake air amount, feedback control mum, total intake air amount, and engine speed, respectively. DESCRIPTION OF SYMBOLS 1... Intake air amount adjustment means, 2... Feedback control means, 3... Intake air addition means at startup, 10.
...Engine, 19...Bypass passage, 20...Solenoid control valve, 21...Control unit.

Claims (1)

[Claims] (1) An intake air amount adjusting means is provided to adjust the amount of intake air supplied to the engine, and the amount of intake air is adjusted by the intake air amount adjusting means so that the engine speed converges to the target idle speed during idling operation. Feedback control means for performing feedback control; and intake air addition at startup for controlling the intake air amount adjusting means to add a predetermined amount of intake air at startup and gradually reduce the added intake air over time. an idle speed control device for an engine, comprising means for controlling the engine idle speed, wherein at the time of starting the engine, the operating range of the engine enters the idle range due to a reduction in the amount of intake air added by the intake air adding means at startup. idling of an engine, characterized in that the control of the intake air amount by the feedback control means is started by using the difference between the intake air amount at that point in time and the basic intake air amount for the feedback control as a feedback control amount; Rotation speed control device.