JPH1193747A - Idle speed controller for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide such an idle speed controller as being capable of satisfactorily controlling rotation in terms of noise and fuel consumption during starting an engine. SOLUTION: Only when an idle stabilized condition judging means M3 judges an idle stabilized condition and learns integration controlled variables, an integration control initial value setting means M4 sets an initial value for the integration controlled variables in the feedback control of learned values for the integration controlled variables by the next engine speed control means M2. The integration control initial value setting means M4, however, prohibits the integration controlled variables increased and corrected when the idle stabilized condition judging means M3 judges the idle stabilized condition during starting an internal combustion engine 2, from being initial values in the next idle stabilized condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an idle speed control device for an internal combustion engine.

[0002]

2. Description of the Related Art As a technique for controlling the number of revolutions of an internal combustion engine at the time of idling, for example, Japanese Unexamined Patent Publication No.
And JP-A-8-114144, the engine speed is feedback-controlled using an integral correction amount obtained based on a difference between a target idle speed and an actual engine speed. is there. In this type of feedback control, a target idle speed corresponding to the operating state of the internal combustion engine is calculated, and an integral correction amount is obtained based on a difference between the calculated target idle speed and the actual engine speed. Further, an expected control amount according to a load change of an air conditioner, a transmission, or the like is obtained. The governor pattern is moved by changing the corrected rotational speed obtained by subtracting the integral correction amount and the expected control amount from the actual engine rotational speed, and control is performed to match the actual engine rotational speed with the target idle rotational speed.

According to the technique disclosed in Japanese Patent Application Laid-Open No. 64-60752, even when the engine speed becomes lower than the lower limit of the target idle speed other than at the time of idling, the integral correction amount accumulated at the time of idling. Is added to increase the fuel supply amount. Therefore, control is performed so that the actual engine speed exceeds the target idle speed. The integral correction amount at this time is updated and stored as it is. Thereafter, when the engine speed becomes lower than the lower limit value of the target idle speed, the stored integral correction amount is adopted as an initial value.

When the vehicle speed is reduced while the engine driving force is transmitted to the wheels, the engine speed may be lower than the lower limit of the target idle speed. Again, in this case,
In the technique disclosed in Japanese Patent Application Laid-Open No. 64-60752, the integral correction amount is increased to increase the fuel supply amount, and the value of the increased integral correction amount is stored and held. Thereafter, when the engine speed is lower than the lower limit value of the target idle speed in a state where the engine driving force is not transmitted to the wheels, the value of the integrated correction amount stored and used is used as an initial value. The degree of increase of the integral correction amount used as the initial value is a value when the engine driving force is transmitted to the wheels, and is very large when the engine driving force is not transmitted to the wheels. As a result, the engine speed in the idle state abnormally increases, resulting in deterioration of noise, fuel consumption, and exhaust emission.

In the technique disclosed in Japanese Patent Application Laid-Open No. 8-114144, the engine speed falls below the target idle speed by at least a predetermined amount in a state other than the idle stable state.
Even if the learning of the integral correction amount is performed and the fuel injection amount is feedback-controlled, the learning value of the integral correction amount at this time is not stored. The idling stable state is defined as a state where the engine driving force is not transmitted to the wheels, a vehicle speed is zero, and an accelerator opening is zero. Then, in the idle stable state thereafter, the learned value of the integral correction amount in the previous idle stable state is adopted as an initial value. The degree of increase in the integral correction amount in the idling stable state is not large, and the engine speed in the idling stable state does not abnormally increase.

[0006]

Problems to be Solved by the Invention
In the technology disclosed in Japanese Patent Application Laid-Open No. 4 (1999) -1995, when the engine speed at the start of the engine rises toward the target idle speed, the accelerator is depressed and the idling becomes unstable. Keep the value. Then, when the accelerator pedal is released and the engine is shifted to the idle stable state, the engine speed is reduced. However, since the integral correction amount is started from the value at the start of accelerator pedal depression, the engine speed is higher than the target idle speed. The state lasts for a long time. That is, the deceleration of the engine speed is poor, and the rotation control immediately after the start of the engine is not satisfactory with respect to noise and fuel efficiency.

In particular, when the engine is in a very low temperature state when the engine is started, it takes time for the engine speed to reach the target idle speed. Therefore, the learning of the integral correction amount is performed until the learning value becomes a large value, and the deceleration of the engine speed described above is further deteriorated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an idle speed control device in which the rotation control at the time of starting the engine is satisfactory with respect to noise and fuel consumption.

[0009]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a speed adjusting means for adjusting a fuel supply amount to adjust a speed of an internal combustion engine, and a target idle speed for setting a target idle speed of the internal combustion engine. Number setting means, a number of rotations detecting means for detecting the number of rotations of the internal combustion engine, and a difference between the target idle speed set by the target idle speed setting means and the number of rotations detected by the number of rotations detecting means. 2. An idle speed control device for an internal combustion engine, comprising: a speed control means for performing feedback control of the speed control means using an integral correction amount obtained based on the idle speed control apparatus. Idle stable state determining means for determining whether or not is in an idle stable state, the idle stable state determining means determines that the idle stable state, and Only when the learning of the minute correction amount is performed, the learning value of the integral correction amount is set as the initial value of the integral correction amount in the feedback control by the next rotation speed control means, and when the internal combustion engine is started, the idle stabilization is performed. An idle speed control device comprising: an integral control initial value setting unit that is not used for the initial value in the next idle stable state with respect to the integral correction amount that is increased when the state determining unit determines that the idle stable state is established. Was configured.

The integral control initial value setting means determines the learning value of the integral correction amount for the next rotation speed control only when the idling stable state determining means determines that the engine is in the idling stable state and when the integral correction amount is learned. The initial value of the integral correction amount in the feedback control by the means is set. However, the integral control initial value setting means sets the integral correction amount increased and corrected when the idle stable state determining means determines that the engine is in the idle stable state at the time of starting the internal combustion engine, as the initial value in the next idle stable state. do not do. Therefore, the initial value of the integral correction amount in the idling stable state again after the start of the engine does not increase, and the state where the engine speed is higher than the target idle speed does not continue for a long time.

In the invention of claim 2, the integral control initial value setting means sets the integral correction amount increased when the idle stable state determining means determines that the engine is in the idling stable state at the time of starting the internal combustion engine. Save processing is not performed.

At the time of starting the internal combustion engine, when the idle stable state determining means shifts from the idle stable state determined as the idle stable state to the non-idle stable state,
The increase correction integrated correction amount is not stored. Therefore, the integral correction amount that has been increased and corrected does not become the initial value of the integral correction amount in the idling stable state again after the engine is started.

According to a third aspect of the present invention, there is provided a cooling water temperature detecting means, wherein the integral control initial value setting means detects the idling stable state judging means by the cooling water temperature detecting means at this time when the idling stable state judging means judges the idling stable state. The integral correction amount set based on the set cooling water temperature is adopted as the initial value.

The integral correction amount set based on the cooling water temperature is preferable as the initial value.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is embodied in a diesel engine idle speed control device will be described below with reference to FIGS.

FIG. 2 shows a distribution type fuel injection pump 1 and a diesel engine 2. The fuel injection pump 1 obtains a driving force via the crankshaft 40 of the diesel engine 2 and the drive pulley 3 on the side of the fuel injection pump 1.

As shown in FIG. 3, a drive shaft 5 connected to the drive pulley 3 has a fuel feed pump 6
And a disk-shaped pulsar 7 are attached. The drive shaft 5 is connected to a cam plate 8. A plurality of cam rollers 10 are mounted on a roller ring 9 disposed between the pulsar 7 and the cam plate 8. Each cam roller 10 faces the cam face 8 a of the cam plate 8, and the cam plate 8 is pressed against the cam roller 10 by a spring 11.

A plunger 12 for pressurizing fuel is rotatably accommodated in a cylinder 14 of the pump housing 13, and the plunger 12 is attached to the cam plate 8 so as to be integrally rotatable. The cam plate 8 and the plunger 12 are reciprocally driven in the left-right direction in FIG. 3 while integrally rotating by transmission of rotational force from the drive shaft 5 to the cam plate 8. A high-pressure chamber 15 is provided between the distal end surface of the plunger 12 and the cylinder 14.

When the fuel feed pump 6 is driven based on the rotation of the drive shaft 5, fuel in a fuel tank (not shown) is supplied into the fuel chamber 21 through the fuel supply port 20. In the suction stroke in which the plunger 12 moves to the left in FIG.
One of a plurality of suction grooves 16 (the same number as the number of cylinders of the diesel engine 2) at the end communicates with a suction port 19 in the pump housing 13, and the fuel in the fuel chamber 21 is introduced into the high-pressure chamber 15. In the compression stroke in which the plunger 12 moves to the right in FIG.
Fuel is pressure-fed from the distribution passage 18 in the cylinder 3 to the fuel injection nozzle 4 of each cylinder.

Spill passage 22 in pump housing 13
Above is provided an electromagnetic spill valve 23 as a rotation speed adjusting means. In the non-energized state, the valve body 2 of the electromagnetic spill valve 23
5 is opened, and the fuel in the high-pressure chamber 15 overflows to the fuel chamber 21. In the energized state, the valve body 25 of the electromagnetic spill valve 23 closes,
Fuel overflow from the high-pressure chamber 15 to the fuel chamber 21 is stopped.
The overflow of fuel from the high-pressure chamber 15 to the fuel chamber 21 is adjusted by controlling the energization time in the coil 24 of the normally-open electromagnetic spill valve 23. When the electromagnetic spill valve 23 is energized during the compression stroke of the plunger 12, the pressure in the high-pressure chamber 15 is reduced, and the fuel injection from the fuel injection nozzle 4 is stopped. If the opening / closing timing of the electromagnetic spill valve 23 is controlled during the compression stroke of the plunger 12, the fuel injection amount from the fuel injection nozzle 4 is controlled.

A timer device 26 is provided below the pump housing 13. The timer device 26 includes a timer housing 27, a timer piston 28 that partitions the inside of the timer housing 27 into a low-pressure chamber 29 and a pressurizing chamber 30, and a timer spring that urges the timer piston 28 from the low-pressure chamber 29 to the pressurizing chamber 30. 31, a slide pin 32 for connecting the timer piston 28 to the roller ring 9 is provided. The position of the timer piston 28 is determined by the pressure opposition between the pressurizing chamber 30 into which the fuel pressurized by the fuel feed pump 6 is introduced and the spring force of the timer spring 31. By this position determination, the position of the roller ring 9 in the rotation direction of the drive shaft 5 is determined, and the reciprocating timing of the plunger 12 is determined. Therefore, by controlling the reciprocating timing of the plunger 12, the engagement timing between the cam roller 10 and the cam face 8a is controlled, and the fuel injection timing at the fuel injection nozzle 4 is adjusted. The pressure in the pressurizing chamber 30 is controlled by a communication passage 34 connecting the pressurizing chamber 30 and the low-pressure chamber 29.
It is adjusted by controlling the duty ratio of the timing control solenoid valve 33 above.

A rotation speed sensor 35 as rotation speed detection means installed opposite to the peripheral surface of the pulsar 7 detects passage of a projection on the peripheral surface of the pulsar 7 and outputs a timing signal corresponding to the engine rotation speed. I do.

As shown in FIG. 2, a sub-combustion chamber 45 communicates with a main combustion chamber 44 formed between a cylinder 41 accommodating a piston 42 and a cylinder head 43. The injected fuel is supplied to the sub combustion chamber 45. 46 is a glow lamp.

An intake pipe 47 connected to the diesel engine 2 is provided with a compressor 49 of a turbocharger 48, and an exhaust pipe 50 connected to the diesel engine 2 is provided with a turbine 51 of the turbocharger 48 and a supercharging pressure. An adjustment wastegate valve 52 is provided. An EGR valve 55 is provided on the recirculation pipe 54 for recirculating a part of the exhaust gas in the exhaust pipe 50 to the suction port 53 of the intake pipe 47 for adjusting the exhaust gas recirculation amount. EGR valve 5
5 is a vacuum switching valve 56 (VSV56)
Open / close control.

An intake pipe 47 for accommodating a throttle valve 58 which is opened and closed in conjunction with depression of an accelerator pedal 57.
A bypass path 59 is provided in parallel with the above-mentioned portion, and a throttle valve 60 is provided in the bypass path 59. The throttle valve 60 is controlled to be opened and closed by an actuator 63, and the actuator 63 is controlled by two vacuum switching valves 61, 62 (VSVs 61, 62). The vacuum switching valves 61 and 62 are controlled by an electronic control unit 71 (ECU 71) according to the operation state.

As shown in FIG. 2 and FIG.
5, 66, 67 and various sensors 35, 72, 73, 7
4, 75, 76, 77 are signal-connected to the electronic control unit 71.

An air conditioner switch 65 detects the operating state of an air conditioner (not shown), and a neutral switch 66
Detects whether the shift position of the transmission is neutral. The starter switch 67 is for operating a starter 68 for starting the engine, and an ON signal of the starter switch 67 is sent to the electronic control unit 71. The intake air temperature sensor 72 detects the temperature of the air taken into the intake pipe 47 via the air cleaner 64, and the accelerator opening sensor 7
3 detects the accelerator opening Ac from the position where the throttle valve 58 is depressed. The suction pressure sensor 74 is connected to the suction port 5
The water temperature sensor 75 detects the cooling water temperature Tw of the diesel engine 2 by detecting the suction pressure in the engine 3. The crank angle sensor 76 detects a rotation reference position of the crankshaft 40, and the vehicle speed sensor 77 detects a vehicle speed Sp.

The electronic control unit 71 includes a central processing unit 79
(CPU 79), read-only memory 80 (ROM 80) for storing a predetermined control program, central processing unit 79
Random access memory 8 for temporarily storing the calculation result of
1 (RAM 81), backup memory 82 for storing pre-stored data, input port 83, output port 8
4, a bus 85, and a clock 78 (CLOCK 78). The sensors 72 to 75 are buffers 86,
Signals are connected to an input port 83 via 87, 88, 89, a multiplexer 93 and an A / D converter 94.
Switches 65, 66, 67 are buffers 90, 91, 92
, And the sensors 35, 76, and 77 are connected to the input port 83 via a waveform shaping circuit 95.

The electromagnetic spill valve 23, the timing control electromagnetic valve 33, the glow lamp 46, and the vacuum switching valves 56, 61, 62 are composed of drive circuits 96, 97, 9
The signal is connected to the output port 84 via 8, 99, 100 and 101.

The central processing unit 79 includes sensors 35, 72 to
77 and the detection signals of the switches 65 and 66 are read as input values, and based on the read input values, the electromagnetic spill valve 23, the timing control electromagnetic valve 33, the glow lamp 46, and the vacuum switching valves 56, 61, 6
2 is controlled.

As shown in FIG. 1, the electronic control unit 71
Target idle speed setting means M1, speed control means M
2. It constitutes idle stable state determination means M3 and integral control initial value setting means M4. The rotation speed adjusting means is constituted by the electromagnetic spill valve 23. The operating state detecting means includes a rotational speed sensor 35, an accelerator opening sensor 73, a water temperature sensor 75, and a vehicle speed sensor 77, which are the rotational speed detecting means. The internal combustion engine is a diesel engine 2.

The flowcharts of FIGS. 5 to 8 show a fuel injection amount calculation routine executed by the central processing unit 79, and this processing is interrupted every predetermined time (for example, 50 ms). Hereinafter, the fuel injection amount control will be described based on the flowcharts of FIGS.

In step S1, a rotation speed sensor 35, an accelerator opening sensor 73, a water temperature sensor 75, a vehicle speed sensor 7
Based on the detection signal from the controller 7, various operation states such as the engine speed Ne, the accelerator opening Ac, the water temperature Tw, and the vehicle speed Sp are read.

In step S2, a target idle speed Ni is calculated based on the various operating states. The target idle speed Ni is set to be lower as the water temperature Tw is higher. The target idle speed Ni is also corrected by the shift position of the transmission.

In step S3, various operations read this time are executed.
Based on the water temperature Tw of the rotation state and the shift position of the transmission.
Accordingly, the proportional correction amount P is calculated. In step S4,
Engine speed Ne read twice and a preset start
The magnitude comparison with the reference rotation speed α is performed. In step S5
Indicates whether the accelerator opening Ac read this time is zero or not.
Is determined. In step S6, this time read
It is determined whether the vehicle speed Sp is zero. Step
The determination results in steps S4 to S7 are all positive.
If it is determined, the starter ON flag is set in step S7.
X_ONIs determined to be 1 or not. Flag X_ON=
1 indicates that the starter switch 67 was ON in the previous routine
Indicates that it was in a state. Flag X _ON= 1
The flag X in step S8._OFFIs the process where
Will be Flag X_OFFIs the starter switch 67 OF
The engine speed Ne after F becomes the target idle speed Ni
Indicates whether it has been reached. Flag X_OFF= 1 is engine rotation
State in which the number Ne has not reached the target idle speed Ni.
Flag X_OFF= 0 means that the engine speed Ne is the target
This shows a state where the idle speed Ni has been reached. In step S9
Is the integral correction amount Q (T
w) is set based on the water temperature Tw. After that, the process
The process moves to step S1 of the next routine.

If the flag X _ON is not equal to 1, a process for incrementing the count value Ct of the counter by a predetermined value β based on the clock signal from the clock 78 is performed in step S10. In step S11, a magnitude comparison between the count value Ct and a preset time Ct1 is performed. If Ct> Ct1, ie, Ne> α, Ac =
0, Sp = 0 and Ct> Ct1 are set to the idle stable state.

If a negative determination is made in any of steps S4 to S7, the count value Ct of the counter is cleared to zero in step S12. Ne> α, Ac = 0, S
It is set that a state where any of p = 0 is not established is an idle unstable state.

If Ct> Ct1 at step S11, that is, if it is determined that the current state is the idle stable state, the processing from step S13 to step S31 described below is performed.

In step S13, the currently read engine speed N is calculated from the target idle speed Ni calculated this time.
The deviation ΔN = Ni−Ne obtained by subtracting e is set. In step S14, a correction term t (ΔN) is calculated based on the set deviation ΔN. The correction term t (ΔN) is the deviation Δ
It is set to take a larger value as N increases.

In step S15, it is determined whether or not the flag X _OFF is 1. If the flag X _OFF = 1, that is, if the engine speed Ne has not reached the target idle speed Ni in the previous routine, step S
At 16, the engine speed Ne and the target idle speed Ni
Is compared with. If Ne ≧ Ni, the process proceeds to step S18 after the process of setting the flag X _OFF to 0 in step S17, and if Ne <Ni, the process proceeds to step S18 with the flag X _{OFF set} to 1. The transition to is performed.

In step S18, it is determined whether the learning flag Y is 0 or not. When the starter switch 67 is turned on, the starter 68 is driven, and the diesel engine 2 is started. The learning flag Y is set to OFF after the explosion in the diesel engine 2 turns on the starter switch 67.
This shows whether the learning of the integral correction amount is performed in a state where the spontaneous explosion of the diesel engine 2 has not occurred after the execution of F. If the learning flag Y = 0, that is, if the learning of the integral correction amount has been performed in the previous routine, the integral correction amount Q determined based on the water temperature Tw in step S19.
(Tw) is set as the initial value Q _old of the next integral control. After setting the initial value in step S19, step S2
After performing the process of setting the learning flag Y to 1 at 0, the process proceeds to step S21. If the learning flag Y is not 0, that is, if the learning of the integral correction amount has not been performed in the previous routine, the process proceeds to step S24 with the learning flag Y being set to 1.

If the flag X _OFF is not equal to 1 in step S15, that is, if the engine speed Ne has reached the target idle speed Ni in the previous routine, whether or not the learning flag Z is 0 is determined in step S21. Is determined.
The learning flag Z indicates whether learning of the integral correction amount has been performed after the explosion in the diesel engine 2 has led to the spontaneous explosion of the diesel engine 2 after the starter switch 67 has been turned off after being turned on. . Learning flag Z
If = 0, that is, if the learning of the integral correction amount has been performed in the previous routine, the integral correction amount Q (Tw) determined based on the water temperature Tw in step S23 is the initial value of the next integral control. Set as value Q _old . Step S22
After setting the initial value in step S23, the process of setting the learning flag Z to 1 is performed in step S23, and then the process proceeds to step S24. If the learning flag Z is not 0, that is, if the learning of the integral correction amount has not been performed in the previous routine,
The process proceeds to step S24 with the learning flag Z set to 1.

In step 24, it is determined whether or not the idle unstable flag Fo for setting the initial value of the integral correction amount is 1. If the idle unstable flag Fo is 1, the integral correction amount of the previous routine is set as the integral correction amount Q in step S25, and the idle unstable flag Fo is set to 0 in step S26. In step S27, it is determined whether or not the current engine speed Ne is equal to the target idle speed Ni. Ne
If = Ni, there is no need to perform integral control, so the flow shifts to step S39.

In step 24, the idle unstable flag F
If o is not 1, the flow shifts to step S27. If Ne ≒ Ni, the engine speed Ne and the target idle speed Ni are compared in step S28. If Ne <Ni, a value [Q + t (ΔN)] obtained by adding the correction term t (ΔN) to the currently set integral correction amount Q in step S29 is set as a new integral correction amount Q. If Ne ≧ Ni, step S3
0, the correction term t (Δ
The value [Q−t (ΔN)] obtained by subtracting N) is set as a new integral correction amount Q. Then, steps S29 and S3
The new integral correction amount Q set at 0 is set at step 31 as the previous integral correction amount Q _old (that is, the initial value in the next integral control).

If Ct ≦ Ct1 in step S11, or after the process of setting the count value Ct to 0 in step S12, that is, if it is determined that the current state is not the idling stable state, The processing from step S32 to step S38 is performed.

In step 32, a magnitude comparison is made between a value (Ni-δN) obtained by subtracting a predetermined amount δN from the target idle rotation speed Ni and the engine rotation speed Ne. Ne ≧ (Ni
In the case of -δN), there is no need to increase the engine speed in order to prevent engine stall, so the process proceeds to step S40. If Ne <(Ni−δN),
Step S because engine stall may occur
At 33, the engine idle speed Ne to the target idle speed N
The value (Ne-Ni) obtained by subtracting i is set as a deviation ΔN, and a correction term t based on the deviation ΔN is set in step S34.
(ΔN) is calculated.

In step S35, it is determined whether or not the idle unstable flag Fo is 0. If the idle unstable flag Fo is 0, the previous integral correction amount Q _old is set as the integral correction amount Q in step S36, and the idle unstable flag Fo is set to 1 in step S37. In Step S38, the correction term t calculated in Step 34 is added to the currently set integral correction amount Q.
The value [Q + t (ΔN)] obtained by adding (ΔN) is set as a new integral correction amount Q. If the idle unstable flag Fo is not 0 in step 35, step S38
The transition to is performed.

After the processing in step S31, step S27
After the determination of Ne = Ni is made in or at step S3
After the process of 8, the sum (P + Q) of the proportional correction amount P calculated in step S3 and the currently set integral correction amount Q is set as the total correction amount ΣQ.

After step S32 or step S39, in step S40, a value obtained by subtracting the total correction amount ΣQ from the current engine speed Ne (Ne- 現在 Q) is set as the injection amount calculation rotation speed Nz. And step S
At 41, the final injection amount Rz is calculated based on the total correction amount ΣQ and the currently read accelerator opening Ac. The final injection amount Rz is set to increase as the accelerator opening Ac increases, and to decrease as the injection amount calculation rotation speed Nz increases. This setting relationship is shown in the governor pattern of FIG. 9, and the final injection amount Rz is smaller than the injection amount Ro corresponding to the actual engine speed Ne by the total correction amount ΣQ
Is set to be larger by ΔR.

In the first embodiment, the following effects can be obtained. (1-1) Curves E1 and C1 in FIG. 10A are from time t1 when the starter switch 67 is turned on to time t2 when the starter switch 67 is turned off.
It shows changes in the engine speed Ne and the integral correction amount Q in a state where the accelerator opening Ac remains zero when the engine speed subsequently increases. The curves Eo and Co in FIG.
In the present embodiment, the engine speed N when the accelerator pedal 57 is depressed when the engine speed increases after the time t2 when the starter switch 67 is turned on from the time t1 when the starter switch 67 is turned off, and the accelerator opening Ac is returned to zero again.
e and changes in the integral correction amount Q. Curves E2 and C2 in FIG. 10B are obtained by turning the starter switch 67 ON and then OFF in the conventional device disclosed in Japanese Patent Application Laid-Open No. 8-114144.
7 shows changes in the engine speed Ne and the integral correction amount Q in a state where the accelerator pedal 57 is depressed when the engine speed increases and the accelerator opening Ac is returned to zero again.

In the conventional device, the learning of the integral correction amount Q is not performed at time t3 when the accelerator pedal 57 is depressed, but the integral correction amount Q1 at this time is changed to the previous integral correction amount Q
This is stored as _old , and this integral correction amount Q1 is adopted as an initial value in the next integral control. Therefore, the integration correction amount Q1 is adopted also at the time point t4 when the accelerator opening Ac is returned to zero, that is, when shifting from the non-idle stable state in which the accelerator pedal 57 is depressed to the idle stable state. Therefore, the deceleration of the engine speed Ne after the accelerator opening Ac is returned to zero is poor, and the rotation control immediately after the start of the engine is not satisfactory with respect to noise and fuel efficiency.

In this embodiment, the integral correction amount Q1 up to the time t1 when the accelerator pedal 57 is started to be _depressed is not stored as the previous integral correction amount _Qold , and this integral correction amount Q1 is used for the next integral correction. It is not used as an initial value for control. That is, steps S19 and S22
As shown in the figure, as an initial value for the next integral control, the integral correction amount Q (T is determined based on the water temperature Tw at the time of transition from the non-idle stable state to the idle stable state.
w) is adopted. Therefore, based on the water temperature Tw at the time of transition from the non-idle stable state to the idle stable state when the accelerator opening Ac is returned to zero, that is, when the accelerator pedal 57 is depressed and the non-idle stable state is shifted to the idle stable state. Correction amount Q determined by
(Tw) is adopted. This integral correction amount Q (Tw) is
Since this is an initial value for learning the integral correction amount in the idling stable state, the integral correction amount is the smallest. Therefore, the deceleration of the engine speed Ne after the accelerator opening Ac is returned to zero is much better than that of the conventional device, and the rotation control immediately after the start of the engine is satisfactory with respect to noise and fuel efficiency. it can. (1-2) Regardless of whether the engine is in the idling stable state or not, when the engine speed Ne becomes somewhat lower than the target idle speed Ni, integral control is performed, and the fuel injection amount increases. As a result, the engine speed is increased. Then, only in the idling stable state and when learning of the integral correction amount Q is performed, the integral correction amount Q is stored as the previous integral correction amount Q _{old and is set} as an initial value of the next integral control. That is, when the integration control is not being performed when the idle control is not being performed,
Integral correction amount Q at this time is not to be stored as the previous integral correction amount Q _old, the previous integral correction amount Q _old in the previous idle stable state is adopted as the initial value in the next integral control. Since the previous integral correction amount Q _old in the idling stable state is not too large as the initial value in the idling stable state, the engine speed does not abnormally increase in the idling stable state. Therefore, the noise of the diesel engine 2 in the idle state other than the time of starting the engine does not become excessive and the fuel efficiency does not deteriorate.

In the present invention, the following embodiments are also possible. (1) Central processing unit 7 serving as idle stable state determination means
9 adopts the integral correction amount when the starter switch 67 is turned on as an initial value when it is determined that the idle state is in the next stable state. (2) A fixed value is used as the integral correction amount when the starter switch 67 is turned on. (3) When shifting from the idle unstable state to the idle stable state at the time of engine start, the integral correction value Q set when the starter switch 67 is turned on is adopted as an initial value. (4) The integral correction amount Q1 at the time point t1 when the accelerator pedal 57 is depressed is stored until the time point t2 when the accelerator opening Ac is returned to zero, that is, when the accelerator pedal 57 is depressed and the non-idle stable state shifts to the idle stable state. To do. (5) When the idle stable state determining means determines that the engine is in the idle stable state, the integral correction amount set based on the cooling water temperature detected by the cooling water temperature detecting means at this time is employed as an initial value. In addition, an integral correction amount set in consideration of the engine speed and the engine load is adopted as an initial value. (6) The present invention is applied to idle speed control of a gasoline engine.

[0054]

As described above in detail, in the present invention, only when the learning of the integral correction amount is performed in the idling stable state, the learning value of this integral correction amount is used as the integral correction amount in the next feedback control. Although the initial correction value is set as an initial value, the integrated correction amount that has been increased and corrected when the internal combustion engine is in the idle stable state is not used as the initial value in the next idle stable state. In this case, there is an excellent effect that noise and fuel consumption can be reduced.

[Brief description of the drawings]

FIG. 1 is a conceptual configuration diagram illustrating a conceptual configuration of the present invention.

FIG. 2 is a cross-sectional view showing the idle speed control device for the diesel engine according to the first embodiment.

FIG. 3 is an enlarged sectional view of the fuel injection pump.

FIG. 4 is a control block diagram.

FIG. 5 is a flowchart showing a fuel injection amount calculation routine.

FIG. 6 is a flowchart showing a fuel injection amount calculation routine.

FIG. 7 is a flowchart illustrating a fuel injection amount calculation routine.

FIG. 8 is a flowchart showing a fuel injection amount calculation routine.

FIG. 9 is a graph of a governor pattern showing a relationship between an engine speed and a fuel injection amount.

FIGS. 10A and 10B are timing charts showing a relationship among an engine speed, an integral correction amount, an accelerator opening, and a starter signal.

[Explanation of symbols]

2 ... Diesel engine which is an internal combustion engine; 23 ... Electromagnetic spill valve which constitutes a revolution speed adjusting means; 35 ... A revolution speed sensor which becomes a revolution speed detecting means; 79 ... Target idle revolution speed setting means; A central processing unit 79 serving as state determination means and integration control initial value setting means;

Claims (3)

[Claims] A rotation speed adjusting means for adjusting a fuel supply amount to adjust a rotation speed of the internal combustion engine; a target idle speed setting means for setting a target idle rotation speed of the internal combustion engine; and a rotation speed of the internal combustion engine. A rotational speed detecting means for detecting the number of rotations, and an integral correction amount obtained based on a difference between the target idle rotational speed set by the target idle rotational speed setting means and the rotational speed detected by the rotational speed detecting means. An idle speed control device for an internal combustion engine, comprising: a speed control device that feedback-controls the speed control device.The idle stable state determining device that determines whether the internal combustion engine is in an idle stable state. The learning of the integral correction amount is performed only when the idle stable state determination means determines that the engine is in the idle stable state and the learning of the integral correction amount is performed. The value is set as the initial value of the integral correction amount in the feedback control by the next rotation speed control means, and the integral correction is increased and corrected when the idle stable state determining means determines that the engine is in the idle stable state at the time of starting the internal combustion engine. An idle speed control apparatus for an internal combustion engine, comprising: an integral control initial value setting means that does not use the initial value in the next idle stable state. 2. The integral control initial value setting means does not perform a storage process for an integral correction amount that has been increased and corrected when the idle stable state determining means determines that the engine is in an idle stable state when the internal combustion engine is started. The idle speed control device for an internal combustion engine according to claim 1. 3. A cooling water temperature detecting means, wherein the integral control initial value setting means determines the cooling water temperature detected by the cooling water temperature detecting means at this time when the idling stable state judging means judges the idling stable state. 2. An integral correction amount set based on the initial value is adopted as the initial value.
An idle speed control device for an internal combustion engine according to any one of claims 2 and 3.