JPH01190945A - Idle revolution speed controller for engine - Google Patents

Abstract

PURPOSE:To stabilize the idle revolution by calculating the standard revolution speed in idle state from the weighted mean value which is obtained by weighting the engine revolution speed in the past and at present and setting the ignition advance angle value according to the difference from the engine revolution speed at present. CONSTITUTION:When an engine is in idling state, an idling speed setting means sets an aimed idling speed, and an intake quantity control means controls the intake quantity of the basis of the aimed idling speed. Further, in idling, a standard revolution speed setting means calculates the weighted means to set the referential revolution speed, by emphasizing the engine speed in the past and at present, for example in the stationary revolution state, emphasizing the value in the past, while emphasizing the value at present for a prescribed time after the change from the aimed idling speed. Then, the ignition advance angle value is set according to the difference from the engine speed at that time, and the ignition timing is controlled by a control means. Therefore, the stable idling state can be obtained speedily.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is directed to adjusting the amount of intake air when the engine is in an idling state in order to keep the engine speed within a predetermined range including the target idle speed. Additionally, the present invention relates to an engine idle speed control device that controls ignition timing.

(Prior Art) In engines used in vehicles, for example, in order to keep the engine speed during idling within a predetermined range that includes the target idle speed, for example, the upstream and downstream parts of the throttle valve in the intake passage are A bypass section that communicates with the side portion is provided, and a flow rate regulating valve is interposed in this bypass section. The opening operation amount of the flow rate adjustment valve is changed,
It is known that so-called idle rotation speed control is performed in which the amount of intake air is controlled.

However, in the above-mentioned idle speed control device that controls the engine speed to match the target idle speed by changing only the amount of intake air, it is difficult to open the flow rate adjustment valve. It takes a certain amount of time for the engine speed to change after the operating amount is changed, so if the engine speed fluctuates in small increments with relatively short cycles, There is a possibility that there will be a delay in following the increase or decrease in the amount of intake air, making it impossible to obtain the stable operating state required of the engine.

Therefore, for example, as disclosed in Japanese Unexamined Patent Publication No. 56-121843, an idle speed control device has been proposed which controls the ignition timing in addition to the amount of intake air. In such an idle speed and number control device, when controlling the ignition timing, the ignition advance value is set according to the engine operating state, and the ignition advance value is set according to the engine operating state. It is set by adding a corrected ignition advance value according to the difference from the target idle rotation speed, and the ignition device is activated at a timing corresponding to the set ignition advance value.

However, in such an idle speed control device, the corrected ignition advance value is set according to the difference between the engine speed at that point and the target idle speed used in intake air amount control. There is a possibility that the control and the intake air amount control may interfere with each other, making it impossible to improve the operational stability of the engine. Therefore, the corrected ignition advance value is calculated by weighting the engine speed at that time and the past engine speed. An idle speed control device has been proposed that sets the speed according to the difference between the load average value and the load average value.

(Problem to be Solved by the Invention) However, in the idle speed control device as described above, the corrected ignition advance value used for controlling the ignition timing is based on the engine speed at that time and the past value. The difference between the load average value calculated based on the engine speed,
Since the engine speed is set according to As a result, the target idle speed is increased in accordance with changes in the load imposed on the engine, and as a result, when the engine speed fluctuates rapidly, it becomes the standard for setting the ignition advance value. Since the weight average value cannot be changed quickly, there is a problem in that it takes a relatively long time for the engine speed to approach the target idle speed.

In view of this, the present invention is designed to control the ignition timing in addition to the amount of intake air in order to keep the engine speed within a predetermined range including the target idle speed while the engine is idling. This can improve the operational stability when the engine is in a steady rotation state, and in addition, after the engine speed fluctuates rapidly due to the target idle speed being changed. The object of the present invention is to provide an engine idle speed control device that can quickly bring the engine speed close to the target idle speed and quickly obtain the stable operating state required for the engine. do.

(Means for Solving the Problems) In order to achieve the above-mentioned object, an engine idle speed control device according to the present invention, as shown in the basic configuration in FIG. an idle rotation speed setting means for setting the rotation speed; and an intake air amount control means for controlling the amount of intake air so that the engine rotation speed is within a predetermined range including the target idle rotation speed when the engine is in an idling state. and a reference rotation speed setting means for setting a reference rotation speed while the engine is in an idling state; an ignition advance value setting means for setting an ignition advance value set by the engine; ignition timing control means that operates at a timing corresponding to the ignition advance value set by the reference rotation speed setting means, and the reference rotation speed set by the reference rotation speed setting means is based on the past engine rotation speed and the engine rotation speed at that time. It is a weighted average value of , and is calculated by weighting the engine rotation speed at that time.

(Function) In the engine idle speed control device according to the present invention having the above-described configuration, the engine is in an idling state. When the engine speed is set within a predetermined range including the target idle speed (the intake air amount control means controls the intake air amount to the engine, and the ignition timing is adjusted to the ignition advance value setting means). In that case, the ignition advance value set by the ignition advance value setting means is controlled according to the reference rotation speed set by the reference rotation speed setting means and the ignition advance value set by the reference rotation speed setting means. The reference rotation speed, which is set according to the difference from the engine rotation speed, and is set by the reference rotation speed setting means in such a case, is a weighted average value of the past engine rotation speed and the engine rotation speed at that point. When the engine is in a steady rotation state, the past engine speed is weighted and calculated, and during a predetermined period after the target idle speed changes, the value is set at that point. It is set to the value calculated by weighting the engine rotation speed.

By doing this, the operational stability of the engine is improved when the engine is in a steady rotation state, and when the target idle speed changes and the engine speed suddenly changes, the ignition timing is adjusted to the engine speed. Since the engine rotation speed can be changed without causing a follow-up delay to fluctuations in the engine rotation speed, it is possible to quickly bring the engine rotation speed close to the target idle rotation speed, and the stable operating state required of the engine can be quickly obtained.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows an example of an engine idle speed control device according to the present invention, together with the main parts of an engine to which the device is applied.

In FIG. 2, an engine body 10 consisting of a cylinder head 11 and a cylinder block 13 is provided with a cylinder 14. A piston 16 is disposed in the cylinder 14, and intake air is taken in through an intake valve 18 and an exhaust valve 19. aisle 20
and an exhaust passage 22 are connected to each other. Also, cylinder 1
A combustion chamber 24 is formed above the piston 16 in the combustion chamber 4, and a spark plug 26 is provided in the combustion chamber 24.

In the intake passage 20, from the upstream side, air filters 28. Air flow meter 30 for detecting intake air amount. A throttle valve 32 that opens and closes the intake passage 20 in conjunction with the accelerator pedal, and a fuel injection valve 36 that injects fuel fed under pressure from a fuel supply system (not shown) toward the intake boat are provided. The throttle valve 32 is bypassed between the upstream and downstream portions of the throttle valve 32 in the passage 20.
Both ends of a bypass section 27 provided with a flow rate regulating valve 25 are connected to each other.

Further, a distributor 44 whose rotating shaft is rotationally driven by a crankshaft is attached to the engine body 10. The distributor 44 is provided with a rotation speed sensor 4G that detects the engine rotation speed, and is connected to an ignition coil section 42 that is integrated with the ignition timing control section 40. Furthermore, in addition to this configuration, a control unit 100 is provided.

The control unit 100 includes an air flow meter 3
A detection signal Sa that indicates the intake air amount obtained from 0, a detection signal Sn that indicates the engine rotation speed obtained from the rotation speed sensor 46, a detection signal Sw that indicates the engine cooling water temperature obtained from the water temperature sensor 38, and a detection signal Sw that indicates the engine rotation speed obtained from the water temperature sensor 38. A detection signal St corresponding to the opening degree of the throttle valve 32 obtained from the degree sensor 48, a detection signal sb corresponding to the pressure in the intake passage 20 obtained from the intake negative pressure sensor 49, etc. are supplied. When the load switch 31, which is operated to activate or stop a load such as an air conditioning compressor driven by an engine, is turned on,
A detection signal Sf is also supplied from the signal forming section 33. The control unit 100 controls these detection signals Sa, Sb,
Sf, Sn.

Based on St, Sw, etc., fuel injection control, intake air amount control, and ignition timing control are performed.

When controlling the fuel injection by the control unit 100, the detection signals Sa and Sn are used to set the basic fuel injection amount based on the amount of intake air and the engine speed, and the detection signal SW is used to set the basic fuel injection amount based on the amount of intake air and the engine rotation speed. A correction value is set according to the operating state of the engine based on the basic fuel injection amount, and the basic fuel injection amount is corrected by the correction value to set the effective fuel injection amount. Then, an injection drive pulse signal Cp having a pulse width corresponding to the set effective fuel injection amount is formed, and the injection drive pulse signal Cp is supplied to the fuel injection valve 36 at a predetermined timing.

As a result, the fuel injection valve 36 receives the injection drive pulse signal Cp.
The fuel injection valve 36 is opened for a period corresponding to the pulse width of the fuel injection valve 36, and fuel is injected from the fuel injection valve 36 toward the combustion chamber 24. It is controlled to a predetermined value.

In addition, when controlling the intake air amount by the control unit 100, if it is detected that the engine is not in an idling state based on the detection signals Sn and St based on the actual engine speed and throttle opening, the control unit 100 ) 100 to the flow rate regulating valve 25 is set to a fixed value Dt, and on the other hand, when it is detected that the engine is in an idling state, , the control value is set as follows.

First, a target idle rotation speed is set based on the operating state of the load switch 31 to which the detection signal Sf is generated. At this time, the target idle rotation speed is set to a larger value when the load switch 31 is in the on state than when it is in the off state. Next, a correction value Dr is set according to the difference between the target idle speed value and the engine speed at that point, and the correction value Df is used to correct the control value, and a new control value is set. is set.

Then, a valve drive pulse signal Ci having a pulse width corresponding to the set control value is generated and supplied to the flow rate regulating valve 25. As a result, the flow rate adjustment valve 25 is kept open for a period corresponding to the pulse width of the valve drive pulse signal Ci, and the amount of air passing through the flow rate adjustment valve 25 is adjusted. The rotation speed is controlled to be within a predetermined range including the target idle rotation speed.

Furthermore, when controlling the ignition timing by the control unit lOO, when it is detected that the engine is not in an idling state, the engine speed and the detection signal sb are set to the basic ignition advance value based on the intake negative pressure. θb is set, and a corrected ignition advance value θk is set according to the engine cooling water temperature, etc., and is added to the basic ignition advance value θb and the corrected ignition advance value θ to obtain an effective ignition advance value θ. is set. On the other hand, when it is detected that the engine is idling, the reference rotation speed is calculated as described below, and the engine rotation speed at that point is subtracted from the reference rotation speed. A correction point degree large advance value θi is set according to the difference, and the above-mentioned basic ignition advance value θb and corrected ignition advance value θi are added to set an effective ignition advance value θ. As a result, the effective ignition advance value θ is set to a smaller value when the current engine speed is higher than the reference speed than when it is lower.

Then, the ignition timing control signal Cq is supplied from the control unit 100 to the ignition timing control section 40 at a timing corresponding to the effective ignition advance value θ.

As a result, the ignition timing control signal C is output from the ignition coil section 42.
A secondary side high pressure pulse is obtained at a time corresponding to q, which is supplied to the ignition plug 26 via the distributor 44, and the ignition plug 26 ignites the air-fuel mixture in the combustion chamber 24 to cause combustion.

When such ignition timing control is performed, with the engine in an idling state, the specific value NAV of the reference rotation speed used in setting the effective ignition advance value θ is:
Formula: Calculated by ゛. In the above equation, NAV□ is a specific value of the already calculated reference rotation speed, Nx is a specific value of the engine rotation speed at that time, Ck is a variable, and KN is a constant. The variable Ck is 1. It is set to the value U when it is detected that the engine is in a steady rotation state. on the other hand,
For example, if the load switch 31 is turned on and the load imposed on the engine is suddenly increased, and it is detected that the absolute value of the fluctuation in engine speed is greater than a predetermined value, When a predetermined period of time has elapsed after the detection, the value y is set to be greater than the value U, and thereafter, each time a unit of time elapses, the value y is decreased by l until it becomes zero.

When the fuel injection, intake air amount, and ignition timing are controlled in this way by the control unit 100, when the engine is in an idling state, for example,
As shown in FIG. 3A, when the compressor is brought into operation from a stopped state at time tl and the level V of the detection signal S' changes from a low level to a high level, at time tl
Since the load imposed on the engine increases after t1, the target idle speed is increased from the value TN to the value TN2, as shown in FIG. 3B, and the actual engine speed before time t1 is increased. The target idle rotation speed takes a higher value than N. Therefore, the pulse width of the valve driving pulse signal Ci supplied to the flow rate regulating valve 25 is gradually increased, and the air passing through the bypass section 27 is increased. The amount is increased gradually.

In addition, as shown in FIG. 3B, immediately after time point 1, the engine speed N is rapidly reduced, and the absolute value of the amount of variation in the engine speed becomes greater than a predetermined value. Therefore, until the time point L2 when a predetermined period Ta has elapsed from the time point L1, the variable Ck is set to the value U as shown in FIG. At the time when the period Tb has elapsed from , it is gradually decreased until , and is returned to the value U at time t.

Therefore, until time t2, the value of the reference engine speed is the weighted average value of the engine speed calculated by weighting the past engine speed, and from time t2 to time t3, This is a weighted average value of the engine rotation speeds calculated by weighting the engine rotation speed N at the time.

As a result, the corrected ignition advance value θi changes from time 1 to 1, as shown in the third diagram. It assumes a relatively large value during the period Ta between and time t2, but after time t2 it assumes a value of zero or a value close to zero. Therefore, after time t2, the engine speed N rapidly approaches the target idle speed value TN2 (it is assumed that
After time t3, the value is assumed to be the value TN or a value close to it.

On the other hand, when the engine is in an idling state and the compressor is changed from an operating state to a stopped state at time t4 and the level ■ of the detection signal Sf changes from a high level to a low level, after time t4, the compressor is As the load decreases, the target idle speed decreases to the value T.
The target idle speed is lowered from Nt to the value TN1, and the target idle speed is lower than the actual engine speed N. Therefore, the pulse width of the valve drive pulse signal Ci supplied to the flow rate regulating valve 25 is gradually reduced, and the amount of air passing through the bypass section 27 is gradually reduced.

In addition, immediately after time L4, the engine speed N is sharply increased by 2, and the absolute value of the amount of variation in the engine speed becomes greater than or equal to a predetermined value. Therefore, the variable Ck is set to the value U until the predetermined period Ta has elapsed from the time t4, and is increased to the value y at the time L5, and when the period Tb has elapsed from the time t5, It is gradually decreased until reaching , and is returned to the value U at time t6.

Therefore, the value of the reference rotational speed is the weighted average value of the engine rotational speed calculated by weighting the past engine rotational speed from time 1 to time 1.
Until this point is reached, the weighted average value of the engine rotation speed is calculated by weighting the engine rotation speed N at that time. As a result, the corrected ignition advance value θi increases after taking a relatively small value during the period Ta between time 4 and time 4, but after time t, it increases to a value at or near zero. Therefore, from point 1- onwards,
The engine speed N rapidly changes to the target idle speed value TN.
, and the time point t approaches.

Hereinafter, it is assumed that the value TN or a value near it is assumed.

On the other hand, even if the weighted average value of the engine rotation speed, which is the reference rotation speed value, is a predetermined period Tb after the engine rotation speed N suddenly changes, no weight is given to the past engine rotation speed value. In the case where the corrected ignition advance value θi changes as shown by the broken line in Figure 3, the engine speed N changes as shown by the broken line in Figure 3B. Therefore, it takes a long time to reach the target idle speed.

In this way, when the engine speed is in a steady rotation state, the weighted average value of the engine speed, which is considered as the reference speed value, is calculated by weighting the past engine speed values. During the predetermined period Tb after the sudden change in engine speed, the current engine speed value is weighted and calculated, thereby ensuring operational stability of the engine when the engine speed is in a steady state. In addition, after a sudden change in engine speed due to an increase in the load imposed on the engine, the effective ignition advance value θ can be changed without causing a delay in following the sudden change in engine speed. Therefore, the engine speed can be quickly brought close to the target idle speed or a value in the vicinity thereof, and the stable operating state required of the engine can be quickly obtained.

Also, when the engine speed changes by 2, the variable C is immediately changed.
By not changing k from the value U to the value y, but changing it from the value U to the value y after a predetermined period Ta has elapsed, when the change in engine speed has a relatively short period, Since the ignition timing is not changed significantly, the operational stability of the engine is prevented from being impaired.

The control unit 100 that performs the above-described control is configured using, for example, a microcomputer, and an example of a program executed by the microcomputer in such a case is shown in the flowcharts of FIGS. 4 and 5. I will explain.

In the intake air amount control program shown in the flowchart of FIG. 4, after starting, in process 101, detection signals Sn, SL, and Sw are generated.

31, etc., and in decision 102, it is determined whether the engine is in an idling state or not based on the engine rotational speed indicated by the detection signal Sn and the throttle opening indicated by the detection signal St. If it is determined that the engine is not in an idling state, the control value is set to a fixed value Dt in process 103, and the process proceeds to process 110, where a valve driving pulse having a pulse width corresponding to the control value is generated. It forms a signal Ci, sends it to the flow regulating valve 25, and returns.

On the other hand, if decision 102 determines that the engine is idling, process 10
4, the load switch 31 to which the detection signal Sf is applied
The target idle speed value TN is set based on the operating state of the engine, etc., and in the subsequent process 105, the basic control value Db is set based on the engine cooling water temperature where the detection signal Sw occurs.
, and proceed to process 106. In process 106, the engine speed value N is subtracted from the target idle speed value TN to calculate the difference ΔN, and in process 107
In step 108, a correction value Df is set according to the difference ΔN, and in the subsequent process 108, the control value is set by adding the correction value Df to the basic control value Db. Process 110 is executed as described above to restore the original value. return.

In the program for ignition timing control shown in the flowchart of FIG. 5, after starting, in process 121, detection signals Sn, Sb, Sw, etc. are taken in, and in process 122, the basic ignition advance angle is determined based on the detection signals Sn and sb. After setting the value θb, the process proceeds to decision 123, where it is determined whether the engine is in an idling state. If it is determined that the engine is not in an idling state, a corrected ignition advance value θk is set in process 124 based on the detection signal Sw.

In the subsequent process 125, the effective ignition advance value θ is set by adding the corrected ignition advance value θk to the basic ignition advance value θb, and in the process 126, the ignition is started at the timing corresponding to the effective ignition advance value θ. The timing control signal Cq is sent to the ignition timing control section 40 and the process returns to the original state.

On the other hand, if decision 123 determines that the engine is idling, process 12
In B, the absolute value 1Δn1 of the amount of variation in engine speed is calculated based on the detection signal Sn. Then, in decision 129, it is determined whether or not the absolute value 1Δn1 is greater than or equal to a predetermined value α. If it is determined that the absolute value 1Δn1 is greater than or equal to the value α, the engine speed has suddenly changed, so step 131 is performed. While setting flag F to 1,
The count number Ct is set as KT and the process proceeds to decision 130. Also, in decision 129, the absolute value 1Δn1
is less than the value α, process 13
Proceed to decision 130 without going through step 1.

In decision 130, it is determined whether flag F is zero, and if flag F is determined to be zero, in decision 132, it is determined whether variable Ck is a predetermined value U. If it is determined that the variable Ck is the value U, in process 133, the value NAV of the reference rotation speed is calculated by the formula: using the already calculated NAV, and in the subsequent process 136. , the corrected ignition advance value θi is calculated using the formula: θi=Kig・Kig is a constant.
(NAV-N), and in process 137, the effective ignition advance value θ is set by adding the basic ignition advance value θb and the corrected ignition advance value θi, and then process 126 is performed as described above. Execute the same to return to the original state.

Further, if it is determined in decision 130 that the flag F is not zero, it is determined in decision 138 whether or not the count number Ct is zero, and the count number C
If it is determined that t is not zero, a new count number Ct is set by subtracting 1 from the count number Ct, and then the process proceeds to process 133, and processes 133, 136, 137, and 126 are executed in the same manner as described above. On the other hand, if it is determined that the count number Ct is zero in decision 138, the variable Ck is set to the value y in process 140, and the flag F is set to zero in the subsequent process 141, and then in process 133 Execute the following steps in the same way as above and return to the beginning. Also, in decision 132, the variable Ck
If it is determined that is not the value U, a new variable Ck is set by subtracting 1 from the variable Ck in process 135, and then processes 133 and subsequent steps are sequentially executed in the same manner as described above to return to the original state.

(Effects of the Invention) As is clear from the above description, according to the engine idle speed control device according to the present invention, the weighted average value of the engine speed, which is the value of the reference speed, is the same as when the engine speed is steady. When the engine is in a rotating state, the past engine speed is weighted and calculated, and during a predetermined period after the target idle speed changes, the engine speed at that time is weighted. In addition to improving operational stability when the engine is in a steady rotation state, the ignition timing can be adjusted earlier after the engine speed changes suddenly due to an increase in the load placed on the engine. Therefore, the engine speed can be quickly brought close to the target idle speed or a value close to it, and the stable operating state required of the engine can be quickly obtained.

[Brief explanation of the drawing]

FIG. 1 is a basic configuration diagram showing an engine idle speed control device according to the present invention in accordance with the claims, and FIG. 2 shows an example of the engine idle speed control device according to the present invention. A schematic configuration diagram showing the main parts of the applied engine, FIG. 3 is a time chart for explaining the operation of the example shown in FIG. 2, and FIGS. 4 and 5 are diagrams of the example shown in FIG. 2 is a flowchart showing an example of a program executed by a microcomputer when the control unit uses the microcomputer. In the figure, 10 is an engine body, 25 is a flow rate regulating valve, 26 is a spark plug, 27 is a bypass section, 40 is an ignition timing control section', 42 is an ignition coil section, and 44 is a distributor. Figure 3

Claims (1)

[Scope of Claims] Idle speed setting means for setting a target idle speed according to the operating state of the engine; and when the engine is in an idling state, the engine speed is set within a predetermined range including the target idle speed. In order to achieve this, an intake air amount control means for controlling the amount of intake air is used, and when the engine is in an idling state, the reference rotation speed is determined by comparing the past engine rotation speed and the engine rotation speed at that time. The weighted average value is set to a weighted value calculated by weighting the past engine speed when the engine is in a steady rotation state, and is set to a weighted average value calculated by weighting the past engine speed, and during a predetermined period after the target idle speed changes. is a reference rotation speed setting means that sets the engine rotation speed at that time to a weighted value, and a reference rotation speed set by the reference rotation speed setting means and the engine rotation speed at that time. ignition advance value setting means for setting an ignition advance value according to the difference between An engine idle speed control device comprising: ignition timing control means for operating the device at a timing corresponding to the ignition advance value set by the ignition advance value setting means.