JPH11141380A - Idle speed control system for vehicle internal combustion engine - Google Patents

Abstract

(57) [Summary] [Problem] To facilitate a transition from a normal idle state to an idle-up state or a transition from an idle-up state to a normal idle state in any state of an automobile An idle speed control device for an internal combustion engine is provided. When an air conditioner switch of an automobile is switched from off to on (from on to off), the expected correction amount of the fuel injection amount is increased at a stretch by the expected correction amount for a load change caused by the operation (stop) of the air conditioner ( After that, the expected correction amount is gradually increased (gradually reduced) with time, and the engine speed NE is gradually increased (gradually reduced), and is set as the target speed in an idle-up state (normal idle state). The gradual increase and the gradual deceleration of the stopped state of the vehicle are set to be larger than the gradual increase and the gradual deceleration of the traveling state.

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 controlling an idle speed of an in-vehicle internal combustion engine, and more particularly, to controlling an idle speed in accordance with a normal idle state or an idle-up state. The present invention relates to an apparatus for performing the above.

[0002]

2. Description of the Related Art In general, the control of the number of revolutions of an engine of an automobile or the like in an idle state is performed in order to improve the efficiency of an external load such as an air conditioner (hereinafter referred to as an "air conditioner") in addition to a normal idle state. The operation is executed in a state where the rotation speed is increased by a predetermined amount from the normal idle state, that is, in an idle-up state.

The transition from the normal idle state to the idle-up state or the transition from the idle-up state to the normal idle state is performed, for example, when the air conditioner switch is turned on and the idle-up operation condition is satisfied. Alternatively, the control is performed when the switch is turned off and the idle-up stop condition is satisfied. At this time, first, an estimated control amount according to a load change due to an operation of the air conditioner and the like and an estimated control amount according to the idle-up rotation speed are obtained.
Next, a target engine speed is calculated depending on whether the engine is in a normal idle state or in an idle-up state, and an integral control amount is obtained based on a deviation between the target engine speed and the actual engine speed. Then, by subtracting the integral control amount and the expected control amount from the actual engine speed to obtain a corrected speed, the governor pattern for obtaining the fuel injection amount is moved in accordance with the corrected speed to obtain the actual engine speed. Is controlled to coincide with the target rotation speed.

Conventionally, various methods have been used for such a transition from the normal idle state to the idle-up state or from the idle-up state to the normal idle state. For example, a method using an apparatus described in Japanese Patent Application Laid-Open No. H6-129292 is known. FIG. 12 and FIG. 13 show an outline of a transition method adopted by the device described in the publication. 12 and 13, each figure (a) shows the transition of the air conditioner switch, each figure (b) shows the transition of the expected control amount (correction amount), and each figure (c) shows the transition of the engine speed. Each is shown.

That is, in the device described in the above publication, when the air conditioner switch is switched from off to on at time t1, as shown in FIG. The up operation condition is satisfied, and the estimated correction amount is increased at a stretch by the estimated correction amount NIP corresponding to the load change caused by operating the air conditioner switch.

Subsequently, from time t1 to time t2, the expected correction amount for the idle-up is gradually increased by an increase / decrease amount ΔNIPAC over time, and further increased by the estimated correction amount NIPACMX in the idle-up state. . At this time, in response to the gradual increase of the expected correction amount for the idle-up, the engine speed NE gradually increases,
At time t2, the engine speed NE becomes the target engine speed NTRG.
Reach one.

On the other hand, at the time of transition from the idle-up state to the normal idle state, as shown in FIG. 13, the idle-up stop condition is satisfied based on the switching of the air conditioner switch from on to off at time t3. Then, the estimated correction amount is reduced at once by the estimated correction amount NIP corresponding to the load variation caused by stopping the air conditioner.

Subsequently, during the period from time t3 to time t4, the idle-up expected correction amount is gradually decreased by an increase / decrease amount ΔNIPAC with time, and further reduced to the normal idle state expected correction amount. At this time, in response to the gradual decrease in the idle-up expected correction amount, the engine speed NE gradually decreases, and at time t4, the engine speed NE reaches the target speed NTRG2.

As described above, the transition from the normal idle state to the idle-up state or the transition from the idle-up state to the normal idle state is performed gradually with the elapse of time, so that the engine speed increases rapidly. The change in the number of revolutions is suppressed, and the occupant of the vehicle is prevented from feeling a shock.

[0010]

By the way, in the above-mentioned conventional apparatus, the magnitude of the increase / decrease amount ΔNIPAC, that is, the transition from the normal idle state to the idle-up state or the idle-up state to the normal idle state Is set to the same value regardless of whether the vehicle is stopped or running. However, in practice, if the speed of the gradual change is too fast while the car is running, a sense of rapid acceleration or deceleration is accompanied. It has been confirmed by the inventor that the occurrence of an unpleasant sensation or an uncomfortable feeling with respect to the change in the engine speed.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object the transition from a normal idle state to the idle-up state or the idle-up state in any state of the vehicle. It is an object of the present invention to provide an idling speed control device for an in-vehicle internal combustion engine which facilitates a transition from a normal state to a normal idle state.

[0012]

In order to achieve the above object, according to the first aspect of the present invention, the engine speed is increased by a predetermined amount from a normal idle state accompanying the operation of an external load when the internal combustion engine is idle. In the transition to the state, and the transition from the state in which the engine speed is increased by the same predetermined amount due to the non-operation of the external load to the normal idle state, the control of the engine speed is performed by gradually changing the engine speed. The idle speed control device further includes detection means for detecting a stop state and a running state of the vehicle. The detection means detects when the stop state of the vehicle is detected and when the travel state is detected. The gist of the invention is to make the gradual change speed of the engine speed different.

According to this structure, the gradual change speed of the engine speed when the stop state of the vehicle is detected by the detection means and the engine speed when the traveling state of the vehicle is detected by the detection means. Different from the rate of gradual change. That is, by setting a suitable gradually changing speed of the engine speed according to the stop state or the running state of the vehicle, the engine speed is increased from the normal idle state accompanying the operation of the external load by a predetermined amount. And the transition from the state in which the engine speed is increased by the same predetermined amount due to the non-operation of the external load to the normal idle state can be suitably performed.

According to a second aspect of the present invention, in the idle speed control device for an on-vehicle internal combustion engine according to the first aspect, the gradual change speed of the engine speed when the stop state is detected is equal to the running state. The point is that the engine speed is faster than the gradual change speed of the engine speed when is detected.

According to a third aspect of the present invention, the gradual change of the engine speed is based on a gradual change of a fuel injection amount supplied to the engine. Is the gist.

According to the second or third aspect of the present invention, the gradual change speed of the engine speed when the stop state of the vehicle is detected by the detection means is determined by detecting the traveling state of the vehicle. Is faster than the gradual change speed of the engine speed when the engine is running. Therefore, in a stopped state of the vehicle, a transition from the normal idle state accompanying the operation of the external load to the state in which the engine speed is increased by a predetermined amount in a relatively short time, and the same predetermined amount accompanying the non-operation of the external load, The transition from the state where the engine speed is increased to the normal idle state is completed. For this reason, for example, when calculating the integral control amount based on the deviation between the current engine speed and the target engine speed for each predetermined period, the gradual change of the engine speed due to each of the above-mentioned transitions of the engine is performed. The influence can be eliminated in a relatively short time.

Further, the engine shifts from the normal idle state accompanying the operation of the external load of the engine to a state where the engine speed is increased by a predetermined amount, and the engine speed is increased by the same predetermined amount due to the non-operation of the external load. Since the change in the engine speed due to the transition from the idle state to the normal idle state is recognized in a relatively short time by the driver of the vehicle, the sense of discomfort with the engine speed can be eliminated. .

On the other hand, the gradual change speed of the engine speed when the traveling state of the vehicle is detected by the detection means is smaller than the gradual change speed of the engine speed when the stop state of the vehicle is detected. Is also slow. Therefore, the transition from the normal idling state accompanying the operation of the external load of the engine to the state in which the engine speed is increased by a predetermined amount relatively slowly, and the engine rotation speed by the same predetermined amount accompanying the non-operation of the external load are performed relatively slowly. The transition from the raised state to the normal idle state is completed.
Therefore, it is possible to prevent the driver of the vehicle from feeling sudden acceleration or deceleration when the engine speed fluctuates due to each of the transitions.

[0019]

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

FIG. 1 is a schematic configuration diagram showing an idle speed control device of a diesel engine mounted on a vehicle, and FIG. 2 is an enlarged sectional view of the distribution type fuel injection pump 1 of FIG.

As shown in FIG. 1, the diesel engine 2 includes a fuel injection pump 1 for supplying fuel to the engine 2. The fuel injection pump 1 has a drive pulley 3 and a drive shaft 5 which are drivingly connected to a crankshaft 40 of the engine 2 via a belt or the like. The fuel injection pump 1 is driven by the rotation of the drive pulley 3 and injects fuel from a fuel injection nozzle 4 provided in each cylinder of the diesel engine 2.

The diesel engine 2 is provided with an auto-matching transmission (not shown) so as to be drivingly connected to the crankshaft 40. In this diesel engine 2, the cylinder bore 4
1, a main combustion chamber 44 corresponding to each cylinder is formed by the piston 42 and the cylinder head 43. A sub-combustion chamber 45 communicating with each main combustion chamber 44 is provided corresponding to each cylinder. Then, the fuel injected from the fuel injection nozzle 4 is supplied to each sub combustion chamber 45.

The diesel engine 2 has an intake passage 47
And an exhaust passage 48 are provided. The intake passage 47 is provided with a compressor 50 of a turbocharger 49 constituting a supercharger, and the exhaust passage 48 is provided with a turbine 51 of the turbocharger 49. The exhaust passage 48 is provided with a waste gate valve 52 for adjusting the supercharging pressure. As is well known, the turbocharger 49 uses the energy of the exhaust gas to rotate the turbine 51, and rotates the compressor 50 on the same axis to increase the pressure of the intake air. By this action, a high-density air-fuel mixture is transferred to the main combustion chamber 44.
To burn a large amount of fuel to increase the output of the diesel engine 2.

The diesel engine 2 is provided with an exhaust gas recirculation device (EGR). The device includes an EGR passage 54 that recirculates a part of the exhaust gas in an exhaust passage 48 to an intake port 53 of an intake passage 47,
It comprises a diaphragm type EGR valve 55 provided in the middle of the passage 54. Further, in order to adjust the opening of the EGR valve 55 by adjusting the introduction of a negative pressure, an electric vacuum regulating valve (EVR) whose opening is adjusted by a duty-controlled electric signal.
V) 56 are provided. And this EVRV56
The opening degree of the EGR valve 55 is adjusted by the operation of, and the EGR amount guided from the exhaust passage 48 to the intake passage 47 through the EGR passage 54 is adjusted by this adjustment.

Further, in the middle of the intake passage 47, there is provided a throttle valve 58 which opens and closes in conjunction with the depression amount of an accelerator pedal 57. A bypass passage 59 is provided in parallel with the throttle valve 58, and a bypass throttle valve 60 is provided in the bypass passage 59. The opening and closing of the bypass throttle valve 60 is controlled by an actuator 63 having a two-stage diaphragm chamber driven by the control of two VSVs (vacuum switching valves) 61 and 62. This bypass throttle valve 6
0 is controlled to open and close according to various operating conditions. For example, it is controlled to a half-open state during idle operation to reduce noise and vibration, to a fully opened state during normal operation, and to a fully closed state during smooth operation to stop smoothly.

As shown in FIG. 2, a drive shaft 5 provided in the fuel injection pump 1 has a drive pulley 3 at a distal end thereof and a disk-shaped pulsar 7 at a proximal end thereof.
On the outer peripheral surface of the pulsar 7, the same number of cutting teeth as the number of cylinders of the diesel engine 2 (FIG. 1) are formed at equal angular intervals, and a plurality of projections are formed at equal angular intervals between each cutting tooth. ing. In the middle of the drive shaft 5, there is provided a fuel feed pump (developed 90 degrees in this figure) 6 composed of a vane type pump. A roller ring 9 is provided at the base end of the drive shaft 5 so as to be rotatable relative to the shaft 5, and the roller ring 9 has a cam roller 10 along the circumference thereof.

The fuel injection pump 1 has a plunger 12 provided coaxially with the drive shaft 5.
A cam plate 8 is attached to the base end of the plunger 12. The cam plate 8 has the same number of cam faces 8 a as the number of cylinders of the engine 2. Here, a coupling (not shown) is accommodated in the roller ring 9, which couples the drive shaft 5 and the cam plate 8 so as to be integrally rotatable, and moves the cam plate 8 and the plunger 12 in the axial direction. Tolerate. The cam plate 8 is always urged toward the cam roller 10 by the spring 11.

Here, when the drive shaft 5 is rotated, the cam plate 8 is rotated integrally with the shaft 5 via the coupling, and the engagement with the cam roller 10 causes the cam plate 8 to rotate by the same number as the number of cylinders. It is reciprocated in the direction. As the cam plate 8 reciprocates, the plunger 12 reciprocates in the axial direction while rotating. That is, the plunger 12 is moved while the cam face 8a of the cam plate 8 rides on the cam roller 10 of the roller ring 9.
Is moved forward (lift), and conversely, the plunger 12 is moved back while the cam face 8a rides on the cam roller 10.

The plunger 12 is fitted into a cylinder 14 formed in the pump housing 13, and a high pressure chamber 15 is formed between a tip surface of the plunger 12 and a bottom surface of the cylinder 14.
It has become. The same number of intake grooves 16 as the number of cylinders of the diesel engine 2
And a distribution port 17 are formed. Further, the pump housing 13 includes the suction groove 16 and the distribution port 17.
, A distribution passage 18 and a suction port 19 are formed.

In the fuel injection pump 1, the drive shaft 5 is rotated to drive the fuel feed pump 6, so that the fuel is supplied from the fuel tank (not shown) to the fuel chamber 21 through the fuel supply port 20. Is supplied with fuel. Also, during the suction stroke in which the plunger 12 is moved back and the high-pressure chamber 15 is depressurized, one of the suction grooves 16 communicates with the suction port 19, so that the high-pressure chamber 1
Fuel is introduced into 5. On the other hand, during the compression stroke in which the plunger 12 moves forward and the high-pressure chamber 15 is pressurized, the fuel is pressure-fed from the distribution passage 18 to the fuel injection nozzle 4 (FIG. 1) of each cylinder and injected.

Further, the high pressure chamber 15 has a fuel chamber 21
An oil passage 22 for fuel overflow (spill) communicating with the spill valve is formed, and an electromagnetic spill valve 23 for adjusting a spill timing is provided in the middle of the oil passage 22. The electromagnetic spill valve 23 is a normally open valve having a solenoid 24. When the solenoid 24 is not energized and the valve 23 is open, the high-pressure chamber 15 communicates with the fuel chamber 21. And the high-pressure chamber 15
The inside is maintained at a reduced pressure. On the other hand, solenoid 2
4 is energized, the electromagnetic spill valve 23 is closed,
The spill oil passage 22 is closed. That is, the electromagnetic spill valve 23 is closed before the forward movement of the plunger 12 corresponding to each fuel injection nozzle 4 and the plunger 12 is closed.
By opening the electromagnetic spill valve 23 during the forward movement of the fuel, the pressure in the high-pressure chamber 15 is reduced, and the fuel injection from the fuel injection nozzle 4 is immediately stopped. Therefore, plunger 1
By controlling the valve opening timing of the electromagnetic spill valve 23 during the forward movement to 2, the end timing of fuel injection from the fuel injection nozzle 4 is changed, and the fuel injection amount is adjusted.

On the other hand, below the pump housing 13, there is provided a timer device (developed at 90 degrees in the figure) 26 for controlling the fuel injection timing. The timer device 26 changes the position of the roller ring 9 with respect to the rotation direction of the drive shaft 5, thereby changing the timing at which the cam face 8a engages with the cam roller 10, that is, the reciprocating timing of the cam plate 8 and the plunger 12. It is for.

The timer device 26 is driven by control hydraulic pressure. A timer housing 27, a timer piston 28 fitted in the housing 27, and a low pressure chamber 29 on one side of the timer housing 27. It includes a timer spring 31 for urging the piston 28 toward the other pressure chamber 30 and the like. The timer piston 28 is connected to the roller ring 9 via a slide pin 32.

In the pressurizing chamber 30 of the timer housing 27,
The fuel pressurized by the fuel feed pump 6 is introduced. The position of the timer piston 28 (hereinafter, referred to as “timer piston position”) is determined based on the balance between the fuel pressure and the urging force of the timer spring 31. Further, by determining the timer piston position, the position of the roller ring 9 is determined, and the reciprocating timing of the plunger 12 via the cam plate 8 is determined.

The timer device 26 is provided with a timer control valve (TCV) 33 for adjusting the fuel pressure acting as the control oil pressure of the timer device 26. That is, the pressurizing chamber 30 and the low-pressure chamber 29 of the timer housing 27 communicate with each other through the communication path 34, and the TCV 33 is provided in the communication path 34. The TCV 33 is an electromagnetic valve that is controlled to open and close by a duty-controlled energization signal.
The fuel pressure inside is adjusted. Then, by adjusting the fuel pressure, the lift timing of the plunger 12 is controlled, and the fuel injection timing from each fuel injection nozzle 4 is controlled.

On the other hand, a rotation speed sensor 35 composed of an electromagnetic pickup coil is mounted on the upper part of the roller ring 9 so as to face the outer peripheral surface of the pulser 7. The rotation speed sensor 35 detects the passage of the projections of the pulsar 7 when they cross, and outputs a timing signal corresponding to the engine rotation speed NE, that is, an engine rotation pulse for each constant crank angle. The rotation speed sensor 35 detects an instantaneous rotation speed for each engine rotation pulse. Further, since the rotation speed sensor 35 is integrated with the roller ring 9, the rotation speed sensor 35 outputs a reference timing signal to the plunger lift at a constant timing regardless of the control operation of the timer device 26.

In addition to the rotational speed sensor 35, the diesel engine 2 is provided with various sensors for detecting the operating state of the engine 2. As shown in FIG. 1, an intake air temperature sensor 72 for detecting an intake air temperature THA is provided near an air cleaner 64 provided at an inlet of the intake passage 47. Also, the throttle valve 58
Near the opening and closing position of the throttle valve 58,
Accelerator opening A corresponding to the load of diesel engine 2
An accelerator sensor 73 for detecting CCP is provided. In the vicinity of the suction port 53, a turbocharger 49 is provided.
An intake pressure sensor 74 for detecting the intake air pressure after supercharging, that is, the intake pressure PM is provided. Further, a water temperature sensor 75 for detecting a cooling water temperature THW of the engine 2 is provided in a water jacket of the engine 2. The engine 2 has a crankshaft 4
A crank angle sensor 76 for detecting a zero engine rotation re-reference position is provided. In addition, the transmission is provided with a vehicle speed sensor 77 for detecting a vehicle speed (vehicle speed) SPD by turning a reed switch 77b on and off by a magnet 77a rotated by rotation of the gear.

Further, the accelerator pedal 57 is provided with an idle switch 36 for detecting that the accelerator pedal 57 is not operated. Further, a neutral switch 66 for detecting that the transmission is neutral is provided.

Further, the air conditioner 37 which is an external load
An air conditioner switch 65 for switching the operation / non-operation of the air conditioner is provided. That is, by turning on / off the air conditioner switch 65, the drive connection / disconnection of the compressor (not shown) of the air conditioner 37 and the crankshaft 40 is performed, and the operation / non-operation of the air conditioner 37 is switched. The air conditioner switch 65 also detects on / off information of the air conditioner 37.

As described above, the electromagnetic spill valve 23 provided in the fuel injection pump 1 and the diesel engine 2, the TCV
33, the EVRV 56, the VSVs 61 and 62, the various sensors 35, 72 to 77, and the switches 36, 65 and 66 are connected to an electronic control unit (hereinafter referred to as "ECU") 71. Then, the ECU 71 determines that each of the sensors 35, 72 to 77
And the electromagnetic spill valve 23, the TCV 33, the EVRV based on the detection signals output from the switches 36, 65, and 66.
56 and the VSVs 61 and 62 are suitably controlled.

Next, the configuration of the ECU 71 will be described with reference to FIG. As shown in the figure, the ECU 71 includes a central processing unit (CPU) 81, a read-only memory (ROM) in which a predetermined control program, function data, and the like are stored in advance.
82, a random access memory (RA) for temporarily storing the calculation result of the CPU 81 and data such as the engine speed NE.
M) 83, battery-backed nonvolatile RA
A backup RAM 84 as M is provided. The ECU 71 is configured as a logical operation circuit in which these units are connected to the input port 85, the output port 86, and the like via a bus 87.

The input port 85 is provided with the above-mentioned intake air temperature sensor 72, accelerator sensor 73, intake air pressure sensor 74 and water temperature sensor 75, and buffers 88, 89, 90, 91, respectively.
It is connected via a multiplexer 93 and an A / D (analog / digital) converter 94. Similarly, the input port 85 is provided with the rotation speed sensor 35, the crank angle sensor 76, and the vehicle speed sensor 77 described above.
Connected through. Further, the idle port 36 and the air conditioner switch 65 are connected to the input port 85.
And the neutral switch 66 is connected to each buffer 102,
They are connected via 103 and 104. And CP
U81 denotes each sensor 3 input via the input port 85.
The detection signals from the switches 5, 72 to 77 and the switches 36, 65, 66 are read as input values. Also, the output port 86
Are connected to the electromagnetic spill valve 23, the TCV 33, the EVRV 56, the VSVs 61, 62, and the like via drive circuits 96, 97, 99, 100, and 101, respectively.

Next, idle speed control (hereinafter referred to as "ISC control") executed by the ECU 71 is described.
Will be described with reference to FIGS. 4 to 9. 4 and 5 show a processing routine for "ISC control", and this processing is periodically executed by a periodic interruption every predetermined time, for example, every 64 ms (milliseconds).

When the process proceeds to this routine, first in step 101, the ECU 71 determines whether the engine speed N
E is read, and the routine proceeds to step 102. Here, the engine speed NE is a value calculated based on the output from the speed sensor 35.

In step 102, the ECU 71 determines whether or not the air conditioner operation determination flag XAC is on.
The air conditioner operation determination flag XAC is turned on when the air conditioner switch 65 is turned on. If it is determined that the air conditioner operation determination flag XAC is ON, the ECU 71 proceeds to step 103.

In step 103, the ECU 71 sets the target rotational speed NT when the air conditioner switch 65 is ON.
RG1 is calculated. The target rotation speed NTRG1 is, for example, the cooling water temperature TH detected by the water temperature sensor 75.
It is calculated based on the map stored in the ROM 80 in accordance with W and the range of the torque converter (D range or N range) set by the neutral switch 66 (higher than when the air conditioner switch 65 is off). Set). Then, the ECU 71 that has calculated the target rotation speed NTRG1 proceeds to step 104.

In step 104, the ECU 71 determines whether the operating state of the engine 2 is an idle state.
This determination is made, for example, by determining whether the idle switch 36 is on and the vehicle speed S detected by the vehicle speed sensor 77.
PD is “0 km / h (km / h)” and accelerator opening ACC detected by accelerator sensor 73
It is determined from whether P is “0 (%)”.

If it is determined in step 104 that the vehicle is in the idle state, the ECU 71 proceeds to step 105. In step 105, the ECU 71 determines a deviation NEDL (= NTRG1) between the target rotational speed NTRG1 and the engine rotational speed NE read in step 101.
-NE), and the routine goes to Step 106.

In step 106, the ECU 71 calculates the deviation NEDL calculated in step 105 according to
The integral correction amount ΔQII is calculated based on a map stored in the ROM 80. Then, the ECU 71 that has calculated the integral correction amount ΔQII proceeds to step 107.

In step 107, the ECU 71 adds the calculated integral correction amount ΔQII to the previous integral correction amount QII (i-1) to obtain the current integral correction amount QII.
(I) is calculated. And the current integral correction amount QII
The ECU 71 that has calculated (i) calculates the same integral correction amount QII
(I) is stored in the RAM 83 as the integral correction amount QII, and the routine proceeds to step 108.

If it is determined in step 104 that the vehicle is not in the idle state, the ECU 71 proceeds to step 108 without calculating the current integral correction amount QII (i).

In step 108, the ECU 71 calculates a load variation expected correction amount QIPB. This expected load variation correction amount QIPB is calculated based on a map stored in the ROM 80 according to the range (D range or N range) of the torque converter set by the neutral switch 66. Here, the expected load variation correction amount QIPB is a correction amount for increasing the fuel injection amount at a stretch when the air conditioner switch 65 is switched from off to on. Therefore, the increase in the correction amount QIPB cancels the increase in the load at the time of operating the air conditioner, thereby avoiding the fluctuation of the engine speed NE. The ECU 71 that has calculated the load variation expected correction amount QIPB
The load variation expected correction amount QIPB is stored in the RAM 83, and the process proceeds to step 109 shown in FIG.

In step 109, the ECU 71 calculates the upper limit value QIPAMX of the expected correction amount for the idle-up due to the turning on of the air conditioner switch 65. The upper limit value QIPACMX is calculated by using the correction terms tKQPA, tKQPAC and the water temperature correction coefficient MNTTTW, as follows: QIPACMX = tKQPA−tKQPAC × MNTTT
It is calculated by W. Here, the correction term tKQPA, t
As the KQPAC, a predetermined value corresponding to the range (D range or N range) of the torque converter set by the neutral switch 66 is selected. These values are all stored in the ROM 80. Further, the water temperature correction term MNTTW is the detected cooling water temperature T.
This is calculated based on the HW using the map shown in FIG. The above correction term tKQPAC and water temperature correction coefficient MNT
The correction of the upper limit value QIPACMX by TW is performed for the following reason.

That is, when the air conditioner switch 65 is in the warm state,
The correction amount necessary for the idle-up due to turning on of the engine is the above-mentioned correction term tKQPA. A small amount of correction is sufficient.
Therefore, the correction term tKQPAC and the water temperature correction coefficient MNTTW are set as correction values corresponding to the cooling water temperature THW in order to subtract a small amount of the correction at the time of cold.

In step 109, the upper limit value QIP
After calculating the ACMX, the ECU 71 proceeds to step 110. Then, in step 110, the change amount ΔQIPAC is calculated based on a routine (to be described later) (change amount ΔQIPAC calculation routine), and the routine proceeds to step 111.

In step 111, the ECU 71 adds the increase / decrease amount ΔQIPAC calculated in step 110 to the previous expected correction amount QIPAC (i-1) for the idle-up due to the turning on of the air conditioner switch 65, and calculates Calculate the quantity QIPAC (i).
The ECU 71 then calculates the calculated expected correction amount QIP
AC (i) is stored in the RAM 83, and the process proceeds to step 112.

In step 112, the ECU 71 calculates the current estimated correction amount QIPAC (i) calculated above.
Upper limit value QIPA calculated in step 109
It is determined whether or not the size is larger than CMX. Here, the current estimated correction amount QIPAC (i) is equal to the upper limit value QIPAC.
If it is determined that it is smaller than MX, the ECU 71 proceeds to step 114, and the idle-up expected correction amount Q
The IPAC is set to the current expected correction amount QIPAC (i), and the subsequent processing is temporarily terminated.

If it is determined in step 112 that the current expected correction amount QIPAC (i) is equal to or larger than the upper limit value QIPACMX, the ECU 71 proceeds to step 11.
3 and the idle-up expected correction amount QIPAC
Is set to the upper limit value QIPACMX, and the subsequent processing is temporarily ended.

On the other hand, if it is determined in step 102 (FIG. 4) that the air conditioner operation determination flag XAC is off, the ECU 71 proceeds to step 115. In step 115, the ECU 71 calculates a target rotation speed NTRG2 when the air conditioner switch 65 is off. The target rotation speed NTRG2 is determined by the air conditioner switch 6
Similarly to the calculation of the target rotation speed NTRG1 in a state in which the cooling water temperature THW is ON, for example, the cooling water temperature THW detected by the water temperature sensor 75 and the neutral switch 66
Range (D range or N)
(The range) is calculated based on the map stored in the ROM 80 (set lower than when the air conditioner switch 65 is on). And the target rotation speed N
After calculating the TRG2, the ECU 71 proceeds to step 116.

In step 116, the ECU 71 determines whether the operating state of the engine 2 is an idle state.
This determination is made in the same manner as in step 104, for example, when the idle switch 36 is turned on, the vehicle speed SPD detected by the vehicle speed sensor 77 is "0 km / h (km / h)", and the accelerator sensor 73 detects the vehicle speed SPD. It is determined based on whether or not the obtained accelerator opening ACCP is “0 (%)”.

If it is determined in step 116 that the vehicle is in the idle state, the ECU 71 proceeds to step 117. Then, in step 117, the ECU 71 determines a deviation NEDL (= NTRG2) between the target rotational speed NTRG2 and the engine rotational speed NE read in step 101.
-NE), and the routine goes to Step 118.

In step 118, the ECU 71 calculates the deviation NEDL calculated in step 117,
The integral correction amount ΔQII is calculated based on a map stored in the ROM 80. Then, the ECU 71 that has calculated the integral correction amount ΔQII proceeds to step 119.

In step 119, the ECU 71 adds the calculated integral correction amount ΔQII to the previous integral correction amount QII (i-1), and adds the current integral correction amount QII.
(I) is calculated. And the current integral correction amount QII
The ECU 71 that has calculated (i) calculates the same integral correction amount QII
(I) is stored in the RAM 83 as the integral correction amount QII, and the routine proceeds to step 120.

If it is determined in step 116 that the vehicle is not in the idle state, the ECU 71 proceeds to step 120 without calculating the current integral correction amount QII (i).

In step 120, the ECU 71 calculates the expected load variation correction amount QIPB in the same manner as in step 108. Here, the load variation expected correction amount QIPB is a correction amount for reducing the fuel injection amount at a stretch when the air conditioner switch 65 is switched from on to off. Therefore, the decrease in the correction amount QIPB cancels the load decrease when the air conditioner is stopped, thereby avoiding the fluctuation of the engine speed NE. The ECU 71 that has calculated the expected load variation correction amount QIPB stores the expected load variation correction amount QIPB in the RAM 83, and proceeds to step 121 shown in FIG.

In step 121, the ECU 71 determines the amount of change ΔQ based on the aforementioned amount of change ΔQIPAC calculation routine.
The IPAC is calculated, and the process proceeds to step 122. In step 122, the ECU 71 determines that the previous expected correction amount Q
The current expected correction amount QIPAC (i) is calculated by subtracting the increase / decrease amount ΔQIPAC calculated in step 121 from IPAC (i−1). And the ECU 71
The calculated expected correction amount QIPAC (i) is stored in RAM 8
3 and go to step 123.

In step 123, the ECU 71 calculates the estimated correction amount QIPAC (i) calculated this time as
It is determined whether or not the value is “0” or less. Here, if it is determined that the current estimated correction amount QIPAC (i) is larger than “0”, the ECU 71 proceeds to step 125, and sets the idle-up expected correction amount QIPAC to the current estimated correction amount QIPAC (i). After setting, the subsequent processing is temporarily terminated.

If it is determined in step 123 that the current expected correction amount QIPAC (i) is equal to or less than "0", the ECU 71 proceeds to step 124 and sets the idle-up expected correction amount QIPAC to "0". Then, the subsequent processing is temporarily ended.

Next, the calculated integral correction amount QII,
The fuel injection amount control based on the load variation expected correction amount QIPB and the idle-up expected correction amount QIPAC will be described with reference to FIG. FIG. 6 shows a processing routine for "fuel injection amount control", and this processing is executed by an angle interruption for each predetermined crank angle.

When the process proceeds to this routine, first, in step 201, the ECU 71 determines the current engine speed NE, the accelerator opening ACCP, the integral correction amount QII calculated during idling, and the expected load correction amount QI.
The values of the PB and the idle-up expected correction amount QIPAC are read from the RAM 83, and the process proceeds to step 202.

In step 202, the ECU 71 obtains the idle governor injection amount tQ from the two-dimensional map shown in FIG. 9 relating to the engine speed NE and the accelerator opening ACCP.
GOV1 and travel governor injection amount tQGOV2 are calculated.
As can be seen from FIG. 9, the idle governor injection amount tQGOV1 is an injection amount when the engine is in a low rotation region, that is, when the vehicle is mainly in an idle rotation state, and is indicated by a broken line in FIG. Also, the traveling governor injection amount tQG
OV2 is the injection amount when the engine is in a high rotation range, that is, when the vehicle is mainly in a running state, and is indicated by a solid line in FIG. The governor injection amounts tQGOV1, tQG
After calculating the OV2, the ECU 71 proceeds to step 203.

In step 203, the ECU 71 calculates a value obtained by adding the calculated integral correction amount QII, the estimated load correction amount QIPB and the estimated idle-up correction amount QIPAC to the idle governor injection amount tQGOV1, and the travel governor injection amount. A value obtained by adding the expected correction amount QIPB for the load variation to the amount tQGOV2 is compared, and the larger value is calculated as the governor injection amount QGOV. Therefore, as roughly determined from FIG. 9, in the low rotation range of the engine 2, that is, when the engine 2 is mainly in the idling state, the idle governor injection amount tQGOV1 has the integral correction amount QII and the load fluctuation expected correction amount QIPB. And the value obtained by adding the idle-up expected correction amount QIPAC tends to be selected as the governor injection amount QGOV,
On the other hand, when the engine 2 is in a high rotation range, that is, when the vehicle is mainly in a traveling state, the traveling governor injection amount tQGOV2
The value obtained by adding the expected variation QIPB to the load variation tends to be selected as the governor injection amount QGOV.

In step 203, the governor injection amount QG
After calculating the OV, the ECU 71 proceeds to step 204 and calculates the maximum injection amount QFULL. Incidentally, the maximum injection amount QFULL is an upper limit value of the amount of fuel to be supplied to each combustion chamber 21 and is a limit value for suppressing a sudden increase in smoke discharged from the combustion chamber 21 and an excessive torque. I have. In step 204, the maximum injection amount QFU
After calculating LL, the ECU 71 proceeds to step 205.

Then, at step 205, the ECU 7
1 is the smaller of the calculated maximum injection amount QFULL and governor injection amount QGOV as the final injection amount QFI.
N is calculated, and the routine proceeds to step 206.

In step 206, the ECU 71 calculates an injection amount command value (time converted value) TSP corresponding to the final injection amount QFIN, and proceeds to step 207. Then, in step 207, the calculated injection amount command value TSP is output, and the subsequent processing is temporarily terminated.
The output of the injection amount command value TSP controls the drive of the electromagnetic spill valve 23 of the fuel injection pump 1 to execute fuel injection.

Next, a description will be given, with reference to FIG. 7, of an “increase / decrease amount calculation routine” for calculating and determining the above-mentioned increase / decrease amount ΔQIPAC in the present embodiment. When the process proceeds to this routine, first in step 301, E
The CU 71 reads the idle stability flag XISTBL. This idle stability flag XISTBL indicates that the torque converter of the neutral switch 66 is in the N range,
And when the idle switch 36 is on, or when the torque converter of the neutral switch 66 is in the D range, the idle switch 36 is on, and the vehicle speed S detected by the vehicle speed sensor 77.
When the PD is “0 km / h”, the flag is set to indicate that the vehicle is in a stopped state. The ECU 71 that has read the idle stability flag XISTBL
Moves to step 302.

In step 302, the ECU 71 determines whether or not the idle stability flag XISTBL is on. If it is determined that the idling stability flag XISTBL is ON, the process proceeds to step 303 assuming that the vehicle is currently in a stopped state. Then, in step 303, the ECU 71 sets the increase / decrease amount ΔQIPAC to a larger value (1.172 in the present embodiment), and terminates the subsequent processing once.

On the other hand, if it is determined in step 302 that the idling stability flag XISTBL is off, it is determined that the vehicle is currently in a running state and step 3
Move to 04. Then, in step 304, the ECU 71 sets the increase / decrease amount ΔQIPAC to a smaller value (0.078 in the present embodiment), and terminates the subsequent processing once.

Next, the control mode of the ISC control according to the present embodiment executed through each of these routines will be described with reference to FIGS. 10 and 11. FIG. FIGS. 10 and 11 show the transition from the normal idle state to the idle-up state accompanying the turning on and off of the air conditioner switch 65 at the time of stopping and running of the vehicle, respectively, and the normal state from the idle-up state to the normal state. It shows a manner of shifting to an idle state. In FIGS. 10 and 11, each figure (a) shows an air conditioner switch 65.
(B) shows the expected control amount (correction amount) QI
The transition of PB + QIPAC, and each diagram (c) shows the transition of the engine speed NE.

First, when shifting from the normal idle state to the idle-up state when the vehicle is stopped, as shown in FIG. 10, the air conditioner switch 65 is turned on from time off at time t11 when the vehicle is stopped. When the switching is performed, the estimated correction amount increases at a stretch by the estimated correction amount QIPB corresponding to the load variation due to the operation of the air conditioner. At this time, although the air conditioner is operated, the expected correction amount is increased by the load increase of the air conditioner, so that the engine speed NE does not change.

Subsequently, between time t11 and time t12, the idle-up expected correction amount is gradually increased by the calculated increase / decrease amount ΔQIPAC over time. Then, due to the gradual increase in the idle-up expected correction amount from time t11 to time t12, the engine speed NE also gradually increases. Since FIG. 10 shows a case where the vehicle is in a stopped state, the larger value (1.172) is adopted as the increase / decrease amount ΔQIPAC.

When the estimated correction amount gradually increases to the upper limit value QIPACMX at time t12 due to the gradual increase of the estimated correction amount, the same upper limit value QIPACCM is set after time t12.
Holds the value of X. That is, at time t12, the engine speed NE reaches the target speed NTRG1 and thereafter maintains the target speed NTRG1.

As described above, when the amount of increase / decrease ΔQIPAC is set to the larger value when the vehicle is stopped, the engine speed NE can be reduced to the target speed NT in a relatively short time.
RG1 is reached. Therefore, in the calculation of the integral correction amount QII when the vehicle is in the idling state,
The effect of the gradual increase in the engine speed NE due to the operation of the air conditioner is eliminated in a relatively short time.

Further, since the increase in the engine speed NE due to the operation of the air conditioner is recognized by the driver of the automobile in a relatively short time, the sense of discomfort with the engine speed NE is eliminated.

On the other hand, when shifting from the idle-up state to the normal idle state when the vehicle is stopped, as shown in FIG. 10, the air conditioner switch 65 is turned on from off at time t13 when the vehicle is stopped. , The expected correction amount is reduced at a stretch by the load correction expected correction amount QIPB due to the stoppage of the air conditioner. At this time, although the air conditioner is stopped, the expected correction amount is reduced by the load reduction of the air conditioner, so that the engine speed NE does not change.

Subsequently, from time t13 to time t14, the idle-up expected correction amount is gradually reduced by the calculated increase / decrease amount ΔQIPAC as time passes. Then, due to the gradual decrease of the idle-up expected correction amount from the time t13 to the time t14, the engine speed NE also gradually decreases. Since FIG. 10 shows a case where the vehicle is in a stopped state, the larger value (1.172) is adopted as the increase / decrease amount ΔQIPAC.

When the estimated correction amount reaches “0” at time t14 due to the gradual decrease of the estimated correction amount, the value of “0” is held after the same time t14. That is, at time t14, the engine speed NE becomes the target engine speed NTR.
G2 is reached, and thereafter, the target rotation speed NTRG2 is maintained.

As described above, by setting the increase / decrease amount ΔQIPAC to a larger value when the vehicle is stopped, the engine speed NE can be reduced to the target speed NT in a relatively short time.
RG2 is reached. Therefore, in the calculation of the integral correction amount QII when the vehicle is in the idling state,
The effect of the gradual decrease in the engine speed NE due to the stoppage of the air conditioner is eliminated in a relatively short time.

Further, since the driver of the vehicle recognizes the decrease in the engine speed NE due to the stoppage of the air conditioner in a relatively short time, the sense of discomfort with the engine speed NE is eliminated.

On the other hand, when shifting from the normal idle state to the idle-up state when the vehicle is running, as shown in FIG. 11, at time t21 when the vehicle is in the running state, the air conditioner switch 65 is turned on from off. When the switching is performed, the estimated correction amount increases at a stretch by the estimated correction amount QIPB corresponding to the load variation due to the operation of the air conditioner. At this time, although the air conditioner is operated, the expected correction amount is increased by the load increase of the air conditioner, so that the engine speed NE does not change.

Subsequently, between time t21 and time t22, the idle-up expected correction amount is gradually increased by the calculated increase / decrease amount ΔQIPAC over time. Then, due to the gradual increase of the idle-up expected correction amount from time t21 to time t22, the engine speed NE also gradually increases. Since FIG. 11 shows the case where the automobile is in a running state, the smaller value (0.078) is adopted as the increase / decrease amount ΔQIPAC.

When the estimated correction amount gradually increases to the upper limit value QIPACMX at time t22 due to the gradual increase of the expected correction amount, the same upper limit value QIPACM is set after the same time t22.
Holds the value of X. That is, at time t22, the engine speed NE reaches the target engine speed NTRG1, and thereafter, the engine speed NERG1 is maintained.

As described above, when the increase / decrease amount ΔQIPAC is set to a smaller value in the running state of the automobile, the engine speed NE relatively gradually decreases to the target engine speed NT.
RG1 is reached. Therefore, it is possible to prevent the driver of the vehicle from feeling a sudden acceleration due to the increase in the engine speed NE caused by the operation of the air conditioner.

When the vehicle shifts from the idle-up state to the normal idle state when the vehicle is running, as shown in FIG. 11, the air conditioner switch 65 is turned on from off at time t23 when the vehicle is in the running state. , The expected correction amount is reduced at a stretch by the load correction expected correction amount QIPB due to the stoppage of the air conditioner. At this time, although the air conditioner is stopped, the expected correction amount is reduced by the load reduction of the air conditioner, so that the engine speed NE does not change.

Subsequently, between time t23 and time t24, the idle-up expected correction amount is gradually reduced by the calculated increase / decrease amount ΔQIPAC with the passage of time. Then, due to the gradual decrease in the idle-up expected correction amount from time t23 to time t24, the engine speed NE also gradually decreases. Since FIG. 11 shows the case where the automobile is in a running state, the smaller value (0.078) is adopted as the increase / decrease amount ΔQIPAC.

When the estimated correction amount reaches "0" at time t24 due to the gradual decrease of the estimated correction amount, the value of "0" is maintained after the same time t24. That is, at time t24, the engine speed NE becomes the target engine speed NTR.
G2 is reached, and thereafter, the target rotation speed NTRG2 is maintained.

As described above, when the amount of increase / decrease ΔQIPAC is set to a smaller value in the running state of the automobile, the engine speed NE relatively gradually decreases to the target engine speed NT.
RG2 is reached. Therefore, the driver of the vehicle is prevented from feeling a sudden deceleration due to the decrease in the engine speed NE due to the stoppage of the air conditioner.

As described in detail above, according to the present embodiment, the following effects can be obtained. When the vehicle is in a stopped state, in the calculation of the integral correction amount QII when the vehicle is in an idling state, the influence of a gradual change in the engine speed NE due to the operation or stop of the air conditioner is relatively short. Can be eliminated.

When the car is in a stopped state, the engine speed NE is determined by the operation or stoppage of the air conditioner.
Is recognized by the driver of the vehicle in a relatively short time, so that the sense of discomfort with respect to the engine speed NE can be eliminated.

When the car is in a running state, the engine speed NE is determined by operating or stopping the air conditioner.
Is relatively gradual, it is possible to prevent the driver of the vehicle from feeling a sudden acceleration or deceleration.

The present embodiment is not limited to the above, but may be modified as follows. As the increase / decrease ΔQIPAC in the present embodiment, 1.172 or 0.078 is adopted according to the time of stopping or running of the vehicle, respectively.
Is set to a value larger than the increase / decrease amount ΔQIPAC during traveling, any other value may be used.

In the present embodiment, the detection result of the idle switch 36 is used to determine the stop state of the vehicle. However, the detection result of the accelerator sensor 73 may be used.

In the present embodiment, an automatic transmission is employed, and the target rotation speeds NTRG1 and NTR are set according to the range (D range or N range) of the torque converter set by the neutral switch 66.
G2, load variation expected correction amount QIPB and correction term tK
QPA and tKQPAC were set or calculated, respectively. On the other hand, a manual transmission may be employed. In this case, the target rotation speeds NTRG1 and NTRG2, the load variation expected correction amount QIPB, and the correction terms tKQPA and tKQPAC may be set or calculated as values unique to the vehicle. Incidentally, in this case, the determination that the vehicle is in the stopped state is made, for example, by the vehicle speed sensor 7.
7 is performed when the vehicle speed SPD detected by step 7 is "0 km / h" and the idle switch 36 is ON.

In this embodiment, when the air conditioner switch 65 is turned on / off, the amount of increase / decrease ΔQIPAC is set for each of the time when the vehicle is stopped and the time when the vehicle is running. On the other hand, when the load other than the air conditioner, for example, the operation of the power steering, is operated, the increase / decrease amount ΔQIPAC is similarly distinguished between when the vehicle is stopped and when the vehicle is running.
May be set.

In this embodiment, the ISC control of the diesel engine has been described, but this may be a gasoline engine. In this case, the engine speed may be adjusted according to the amount of air supplied to the engine.

Next, technical ideas other than the claims that can be grasped from the above embodiment will be described below together with their effects. An idle speed control apparatus for an on-board internal combustion engine according to claim 2, wherein the gradual change in the engine speed is caused by a gradual change in the amount of air supplied to the engine. apparatus. According to this configuration, the same effect as in claims 1 and 2 can be obtained by controlling the amount of air supplied to the engine, that is, controlling the air-fuel ratio.

According to the third aspect of the present invention, in the idle speed control apparatus for an on-vehicle internal combustion engine, a shift from a normal idle state accompanying the operation of the external load to a state in which the engine speed is increased by a predetermined amount, and a control of the external load. At the time of the transition from the state in which the engine speed is increased by the same predetermined amount due to the non-operation to the normal idle state, the fuel injection amount is controlled at a stroke corresponding to the load fluctuation accompanying the transition, and then the same fuel An idle speed control device for an in-vehicle internal combustion engine, characterized in that the injection amount is controlled in a gradual manner. According to this configuration, the control of the fuel injection amount corresponding to the load variation corresponding to the operation or non-operation of the external load is performed at a stretch. Therefore, it is possible to avoid a change in the engine speed due to a load change due to the operation or non-operation of the external load.

[0108]

According to the first aspect of the present invention, by setting a suitable gradually changing speed of the engine speed in accordance with the stop state or the running state of the vehicle, the normal idle speed accompanying the operation of the external load is set. It is possible to suitably perform the transition from the state to the state in which the engine speed is increased by a predetermined amount, and the transition from the state in which the engine speed is increased by the same predetermined amount due to the non-operation of the external load to the normal idle state. it can.

According to the second or third aspect of the present invention, for example, when the integral control amount is calculated based on the deviation between the current engine speed and the target engine speed every predetermined period, the external load of the engine is calculated. From the normal idle state associated with the operation of the engine to a state in which the engine speed is increased by a predetermined amount, and from the state in which the engine speed is increased by the same predetermined amount due to the non-operation of the external load, to the normal idle state Thus, the influence of the gradual change of the engine speed due to the above-mentioned operation can be eliminated in a relatively short time.

Further, the engine shifts from the normal idle state accompanying the operation of the external load of the engine to a state where the engine speed is increased by a predetermined amount, and the engine speed is increased by the same predetermined amount due to the non-operation of the external load. Since the change in the engine speed due to the transition from the idle state to the normal idle state is recognized in a relatively short time by the driver of the vehicle, the sense of discomfort with the engine speed can be eliminated. .

Further, a transition from the normal idling state accompanying the operation of the external load of the engine to a state in which the engine speed is increased by a predetermined amount, and a change of the engine speed by the same predetermined amount accompanying the non-operation of the external load. When the engine speed fluctuates due to the transition from the raised state to the normal idle state, it is possible to prevent the driver of the vehicle from feeling a sudden sense of acceleration or a sense of deceleration.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a diesel engine idle speed control device according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a configuration of a fuel injection pump of the diesel engine.

FIG. 3 is a block diagram showing a circuit configuration of an ECU.

FIG. 4 is a flowchart showing an ISC control routine according to the embodiment;

FIG. 5 is a flowchart showing an ISC control routine according to the embodiment;

FIG. 6 is a flowchart showing a fuel injection amount control procedure according to the embodiment;

FIG. 7 is a flowchart showing an increase / decrease amount calculation procedure according to the embodiment;

FIG. 8 is a map showing a relationship between a cooling water temperature and a water temperature correction coefficient.

FIG. 9 is a map showing a relationship between an engine speed and a governor injection amount.

FIG. 10 is a time chart showing a control mode of the engine speed according to the embodiment.

FIG. 11 is a time chart showing a control mode of the engine speed according to the embodiment.

FIG. 12 is a time chart showing a control mode of an engine speed of a conventional device.

FIG. 13 is a time chart showing a control mode of an engine speed of a conventional device.

[Explanation of symbols]

1. Fuel injection pump 2. Diesel engine 35.
Revolution speed sensor, 36 ... idle switch, 37 ... air conditioner, 40 ... crankshaft, 65 ... air conditioner switch, 66 ... neutral switch, 71 ... ECU, 73
... accelerator sensor.

Claims (3)

[Claims] 1. A transition from a normal idle state accompanying an operation of an external load when the internal combustion engine is idling to a state in which the engine speed is increased by a predetermined amount, and an engine speed only by the same predetermined amount due to non-operation of the external load In the idle speed control device of the vehicle-mounted internal combustion engine, which performs the control of the engine speed in a gradual manner at the time of transition from the raised state to the normal idle state, a detecting means for detecting a stop state and a running state of the vehicle An idling speed of the vehicle-mounted internal combustion engine, wherein the speed of change of the engine speed is made different between when the stopped state of the vehicle is detected and when the traveling state is detected by the detecting means. Speed control device. 2. The gradual change speed of the engine speed when the stop state is detected is faster than the gradual change speed of the engine speed when the traveling state is detected. An idle speed control device for an on-board internal combustion engine. 3. The idle speed control device for an on-vehicle internal combustion engine according to claim 2, wherein the gradual change of the engine speed is caused by a gradual change of a fuel injection amount supplied to the engine.