JP2653843B2 - Engine idle rotation control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION (Field of Industrial Application) The present invention relates to an idle rotation control device for an engine, and more particularly, to increasing the air supply amount to the engine during idling operation after starting the engine and reducing the engine rotation speed. The present invention relates to a system in which feedback control is performed at a predetermined rotation speed.

(Prior Art) Conventionally, as an idle rotation control device for an engine, for example, as disclosed in Japanese Patent Publication No. 63-18015, a throttle valve for adjusting an intake flow rate is provided in an intake passage of an engine, The throttle valve is provided with a bypass passage, and a control valve is provided in the bypass passage. During idle operation in which the throttle valve is closed, the engine speed is feedback-controlled to the target speed by adjusting the opening of the control valve. Are known.

In (INVENTION Problems to be Solved) such idle speed control, in order to feedback control the engine speed with the engine stable, as shown in FIG. 9 (b), than the target rotational speed N _O also high-th place in the feedback start rotational speed (N _O + N ') have set up, the engine speed is feedback start rotational speed (N _O + N') rows to start the feedback control from getting below Will be

On the other hand, since the combustion state is unstable immediately after the start of the engine, as shown in FIG. 9 (a), the amount of air supplied to the engine is increased at the same time as the start of the engine, and is decreased at a predetermined gradient. By performing "tailing"
Techniques for activating combustion are known. When the increase is performed after the start, the increase in the air supply amount is determined, for example, in accordance with the engine coolant temperature.

By the way, when performing the increase after the start and performing the idle rotation control as described above, when the increase amount of the air supply amount is set large due to a low engine coolant temperature or the like, the engine rotation speed is reduced. The air supply amount is increased by the tailing even after the rotation speed becomes equal to or lower than the feedback start rotation speed. Therefore, as shown in FIG. 9 (c), the feedback amount is largely reduced to the negative side in order to reduce the air supply amount. Will be done.
In this case, since the correction speed of the feedback amount cannot be set so fast to prevent hunting, the correction of the feedback amount is delayed and the erroneous correction is performed even after the engine rotational speed becomes equal to or lower than the target rotational speed. As a result, as shown in FIG. 9 (b), there is a problem that "rotation drop" occurs in which the engine speed is significantly lower than the target speed.

The present invention has been made in view of such a point, and an object thereof is to set the engine speed to be equal to or less than the feedback start speed when the increase in the air supply amount is set to be large due to the increase in the amount after starting. An object of the present invention is to prevent the feedback amount from being overcorrected and, hence, from being erroneously corrected by making it difficult to enter the feedback region.

(Means for Solving the Problems) In order to achieve the above object, according to the present invention, the larger the increase amount of the air supply amount in the post-start increase, the lower the feedback start rotation speed in the idle rotation control is to be corrected.

Specifically, as shown in FIG. 1, the solution taken by the present invention includes an air adjusting means 11 for adjusting the amount of air supplied to the engine during idling operation, and increasing the amount of air supplied after starting the engine. Air increasing control means 41 for controlling the air adjusting means 11 so as to decrease at a predetermined gradient afterwards,
A rotational speed detecting means 24 for detecting the rotational speed of the engine, and a rotational speed for feedback-controlling the engine rotational speed by the air adjusting means 11 when the output of the rotational speed detecting means 24 reduces the engine rotational speed to or below the feedback start rotational speed. A control means 42, and a feedback start rotation speed correction means 43 for correcting the feedback start rotation speed in the rotation speed control means 42 to be lower as the increase amount of the air supply amount in the air increase control means 41 is larger. It was done.

(Operation) With the above configuration, in the present invention, the air increase control means 41
As a result, the air supply amount to the engine increases after the engine is started and then decreases at a predetermined gradient, so that the combustion is activated immediately after the engine is started and the combustion state is stabilized.

Further, based on the detection of the engine rotation speed by the rotation speed detection unit 24, when the engine rotation speed becomes equal to or lower than the feedback start rotation speed by the control of the air adjustment unit 11 by the rotation speed control unit 42, the engine rotation speed is controlled by the air adjustment unit 11. Is feedback-controlled, so that feedback control of the engine speed is performed in a stable state of the engine.

In this case, the feedback start rotation speed in the rotation speed control means 42 is corrected to be lower as the increase amount of the air supply amount in the air increase correction means 41 is increased by the correction of the feedback start rotation speed correction means 43. When the increase amount of the air supply amount is set to be large due to the increase, the engine speed becomes difficult to enter the feedback region, and the feedback amount is prevented from being overcorrected and erroneously corrected, thereby preventing "rotation drop".

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 2 shows an engine provided with an idle rotation control device according to an embodiment of the present invention. In the figure, 1 is an engine body, 2 is a cylinder formed in the engine body 1,
Reference numeral 3 denotes a piston slidably fitted in the cylinder 2, and a combustion chamber 4 is formed in the engine body 1 by the cylinder 2 and the piston 3.

An intake passage 7 is connected to the combustion chamber 4, and the intake passage 7 is opened to the atmosphere via an air cleaner 8. The intake passage 7 is provided with a throttle valve 9 for adjusting an intake flow rate, that is, an air supply amount to the engine. Further, a bypass passage 10 for bypassing the throttle valve 9 is provided in the intake passage 7.
Is provided with a control valve 11. The control valve 11 constitutes air adjusting means for adjusting the amount of air supplied to the engine during idling operation when the throttle valve 9 is closed.
Reference numeral 13 denotes an exhaust passage connected to the combustion chamber 4.

The operation of the control valve 11 is controlled by the control unit 20. Reference numeral 21 denotes an air flow sensor provided in the intake passage 7 for detecting an intake air flow rate.
Reference numeral 22 denotes an idle switch that is turned on when the throttle valve 9 is fully closed. Reference numeral 23 denotes a water temperature sensor provided on a water jacket of the engine body 1 for detecting a cooling water temperature. Reference numeral 24 denotes a rotation speed sensor for detecting an engine rotation speed. , 25 is a starter switch for turning on a starter (not shown), 26 is an MT switch for detecting whether or not the transmission is a manual type transmission, 27 is a manual type transmission in a neutral position Neutral switch for detecting whether or not
28 is a clutch switch for detecting whether or not a clutch (not shown) is engaged, 29 is an automatic switch
ND switch for detecting whether the transmission of the type is in a neutral range position or a drive range position, a vehicle speed switch 30 that operates according to the vehicle speed, and these sensors and switches 21 to 30
Is input to the control unit 20. The rotation speed sensor 24 constitutes a rotation speed detecting means for detecting the rotation speed of the engine.

Next, the operation of the control unit 20 is controlled by a third control.
A description will be given based on the flowchart of FIG. 4 and FIG. Figure 3 is a flowchart for determining whether the engine is in the feedback condition, first, it is determined whether or not the vehicle equipped with manual type transmission in step S _1, the manual type engine is equal to or no load is disconnected from the driving system in step S ₂ in the case of YES at step so as to prohibit the engine idle speed control when the NO which is connected to the driving system S _{In step 3} , the feedback control flag F _{ID is set} to "0" and the routine returns.

On the other hand, the process proceeds to step S ₄ the determination in Step S ₁ determines that when NO is the transmission of the automatic type, or a range position in said step is in the neutral range position, or and the vehicle speed in the drive range position It is determined whether it is 3 km / h or less. Then, when the determination at step S ₄ NO, the feedback control flag F _ID at step S ₅ so as to prohibit it is determined that is under load to the engine idle speed control
To "0" and return.

Further, when the determination in step S ₂ is YES, or when the determination is YES step S _4, either be determined that the engine is unloaded, the idle switch 22 is turned on operation in the next step S ₆ and it is judged whether or not the that the feedback control flag F _ID at step S ₃ in order to prohibit the idling speed control when not in oN operation and then returns to "0". On the other hand, if larger than the increase amount Q _SW of the air supply amount is "0" in the step S ₇ determines that the throttle valve 9 is idling have fully closed when the determination in step S ₆ is YES whether Is determined. Then, it has not been increased after the start-up _{"Q SW B = 0" N} E at step S ₈ to set the feedback start rotation speed N _O + N _B "when of whether equal to or less than the feedback start rotational speed or not. then, the feedback control flag F _ID at step S ₅ so as to prohibit the idling speed control, if not in the feedback region when the nO is _{"N E> N O + N} B""0" in the returns. Meanwhile , the _{"N E ≦ N O + N} B" in a step S ₉ to declare the establishment of feedback execution conditions in the feedback control flag F _ID in order to perform an idle rotation control as entered in the feedback region when the YES "1" the process returns to stand. Then, so that the engine rotational speed N _E is feedback controlled to the target rotational speed N _O based on the feedback control flag F _ID.

On the other hand, the after-start increment is made when the determination in Step S ₇ is YES, the as shown in FIG. 7, and change settings in the feedback start rotational speed _{"N O + N A" (} N B> N A) N _E at step S ₁₀ Te determines whether equal to or less than the feedback start rotational speed. _{Then, "N E> N O +} N A"
And then returns to the feedback control flag F _ID at step S ₃ in order to prohibit the idling speed control "0" if not in the feedback region when the NO is. On the other hand, “N
_{When E} ≦ N _O + N _A "YES, it is determined that the vehicle is in the feedback range and the step for executing the idle rotation control is performed.
Declare the establishment of feedback execution condition S ₉ returns after made a "1" to the feedback control flag F _ID.

Further, FIG. 4 is a flowchart for executing the after-start increment and the engine rotational speed feedback control when the after-start increment execution, first, in the "0" after-start increment flag F _ST at step S ₂₁ , it is determined whether the starter is turned on operates at step S _22, is on working YE
Because when the S is starting to return to step S _21,
Engine speed is determined whether a predetermined rotation speed α or on-operation to have no step S ₂₃ when the NO, "N _E <
"Returning to step S ₂₁ as in the case of a NO engine is not complete explosion, on the other hand," alpha N executing the after-start increment is determined that is the engine complete explosion when _E ≧ alpha "is YES I do.

That is, it is determined whether post-increase flag F _ST is "1" or start in the next step S _24, since at this stage is "0", the process proceeds to step S _25, as the increase amount Q _SW of the air supply amount set Q _SW1, sets a "1" to the after-start increment flag F _ST in step S _26. Here, the increase amount Q _SW of the air supply amount is determined based on FIG.

Then, the feedback control flag F _ID at step S ₂₇
It is determined whether or not. In that case, immediately after the start of the increase in the engine speed, the engine speed _NE is still the feedback start speed “N _O
"Is greater than, the flow proceeds to step S _28, the feedback amount Q _NFB" + N _B to 0 ", the air supply amount Q in step S _29, a basic supply quantity Q _B, the load supply quantity Q corresponding to the load _L and
And the feedback amount Q _NFB, by the increase amount Q _SW by after the start increase, calculated in _{"Q = Q B + Q L} + Q NFB + Q SW", and outputs the air supply amount Q in step S _30, the control valve (Air adjustment means) Adjusts the opening of 11.

Then, the process returns to step S _22, when reaching the step S _24,
Since the after-start increment flag F _ST is "1", in step S _31, to reduce the increase in Q _SW of the air supply amount Delta] Q _S only performs the "tailing", this in the next step S ₃₂ increases the amount Q _SW is determined whether less than _{"0", "Q SW ≧} 0" when NO is the the process proceeds directly to step S ₂₇ it is determined to be in "tailing", "Q _SW < when the YES 0 "in the step S ₃₃ as the after-start increment is terminated Q _SW
The process proceeds to step S ₂₇ from and to "0".

When the engine rotational speed N _E is feedback start rotational speed "N _O + N _B" becomes less the determination in step S ₂₇ becomes to YES, calculated on the basis of the target rotational speed N _O in Figure 6 in step S ₃₄ , the engine speed at step S ₃₅ N _E and the target rotation speed N
Comparing the _{O, "N O> N E} "" in the step S ₃₆ at the time of Q
_NFB = Q _NFB + _ΔQ "by increasing the correction amount of feedback Q _NFB," N _O <"in the step S ₃₇ at the time of," N _E Q _NFB = Q
_NFB + ΔQ "to reduce and correct the feedback amount Q _NFB ,
When the "N _O = N _E" will maintain the feedback amount Q _NFB, respectively to calculate the air supply amount Q in step S _29, and outputs the air supply amount Q in step S _30, the control valve (air adjustment means Adjust the opening of 11).

In each flow above, steps S ₂₄ ~ Step S ₂₆
And in step S ₃₁ ~ step S _33, since by increasing the air supply to the engine after the start of the engine, the air adjustment means so as to reduce at a predetermined gradient (control valve 1
It constitutes an air increase control means 41 for controlling 1). Further, in step S ₂₇ ~ step S ₃₀ and step S ₃₄ ~ step S _37, the rotational speed detection means (rotation speed sensor 2
When the output of 4) is received and the engine speed becomes equal to or lower than the feedback start speed, the air adjusting means (control valve) 11 constitutes a speed control means 42 for feedback controlling the engine speed. In addition, step S ₇ ~ step
The S _10, constitute a feedback start rotational speed correction means 43 for correcting low feedback starting speed for the rotational speed control means 42 the larger the increase of the air supply amount of the air amount increase control means 41.

Therefore, in the above embodiment, the air supply amount to the engine increases after the engine is started by the control of the air adjusting means (control valve) 11 by the air increase control means 41 and then decreases at a predetermined gradient. Immediately after starting, combustion is activated and the combustion state is stabilized.

Further, based on the detection of the engine speed by the speed detecting means (speed sensor) 24, the engine speed becomes equal to or less than the feedback start speed by the control of the air adjusting means (control valve) 11 by the speed control means 42. Since the engine speed is feedback-controlled by the air adjusting means (control valve) 11, feedback control of the engine speed is performed in a stable state of the engine.

In this case, the feedback start rotation speed in the rotation speed control unit 42 is corrected to be lower as the increase amount of the air supply amount in the air increase control unit 41 is increased by the correction of the feedback start rotation speed correction unit 43. When the increase amount of the air supply amount is set to be large by the increase, the engine speed becomes difficult to enter the feedback region. As a result, as shown in FIG. 8, overcorrection of the feedback amount and hence erroneous correction are prevented, and "drop of rotation" is prevented.

(Effect of the Invention) As described above, according to the engine idle rotation control device of the present invention, after the engine is started, the air supply amount to the engine is increased and then reduced at a predetermined gradient, and the engine speed is reduced. When the engine speed becomes equal to or less than the feedback start rotation speed, the engine speed is feedback-controlled by adjusting the supply amount, and the feedback start rotation speed is corrected to be lower as the increase amount of the air supply amount is larger. When the increase amount of the air supply amount is set to be large, it becomes difficult for the engine speed to enter the feedback region, and overcorrection of the feedback amount and hence erroneous correction can be prevented, so that "rotation drop" can be effectively prevented.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of the present invention. Also,
2 to 8 exemplify an embodiment of the present invention, FIG. 2 is an overall schematic configuration diagram, FIGS. 3 and 4 are flow chart diagrams showing operation control of a control unit, and FIG. FIG. 6 is a characteristic diagram showing a target rotational speed, FIG. 7 is an explanatory diagram showing a feedback execution rotational speed, and FIG. 8 is a diagram showing an engine rotational speed according to the present invention and the conventional example. It is explanatory drawing which compared fluctuation | variation. FIG. 9 is an explanatory view showing "rotation drop" according to the conventional example. 11 ... air adjustment means (control valve), 24 ... rotation number detection means (rotation number sensor), 41 ... air increase control means, 42 ... rotation number control means, 43 ... feedback start rotation number correction means.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-63158 (JP, A) JP-A-60-19937 (JP, A) JP-A-57-59040 (JP, A) JP-A-61-59 49147 (JP, A)

Claims (1)

(57) [Claims] 1. An air adjusting means for adjusting an air supply amount to an engine during an idling operation, and controlling the air adjusting means so as to increase the air supply amount after the engine is started and then decrease the air supply amount at a predetermined gradient. Air increase control means, rotation number detection means for detecting the number of rotations of the engine, and feedback control of the engine rotation number by the air adjustment means when the output of the rotation number detection means becomes lower than the feedback start rotation number. And a feedback start rotation speed correction means for correcting the feedback start rotation speed in the rotation speed control means to be lower as the increase amount of the air supply amount in the air increase amount control means is increased. Characteristic engine idle rotation control device.