JPH06213045A - Internal combustion engine speed controller - Google Patents

Abstract

PURPOSE:To prevent a driver from feeling any shock by checking any variation in sudden engine speed at the time of transition between a normal idling state and an idle-up state. CONSTITUTION:After an air conditioner is selected from the stopped state to the operating state (time t1), if an apparent compensation value NIP is gradually altered, an integral control variable NII to be found after integrating a learning compensation value to be found out of a deviation between target engine speed and actual engine speed is suddenly altered as shown in a broken line because the actual engine speed is gradually altered. Contrary to this, in addition to the apparent compensation value NIP of an idle-up portion, the target engine speed NTRG is also gradually altered along with a secular span, whereby the deviation between the target engine speed NTRG and the actual engine speed NE becomes lessened, and the integral control variable NII will in no case suddenly be altered in a temporary way. In consequence, engine speed is prevented from being suddenly changed, so that any shock based on an unnecessary vibration in a diesel engine 1 is not felt to a driver at all.

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, which controls the speed of the internal combustion engine at idle.

[0002]

2. Description of the Related Art Conventionally, as a technique for controlling the rotational speed of an in-vehicle engine at an idle time, for example, Japanese Patent Laid-Open No. 57-57157 is available.
There is one disclosed in Japanese Patent Laid-Open No. 181940. In this technology, first, a target rotation speed according to the operating state of the diesel engine is calculated, a learning correction amount is obtained based on the deviation between this target rotation speed and the actual rotation speed, and this learning correction amount is added and integrated. To obtain the integral control amount. Next, the expected control amount according to the load fluctuation of the air conditioner (air conditioner), automatic transmission, etc. is obtained. Then, the integrated control amount and the expected control amount are subtracted from the actual rotation speed to obtain the corrected rotation speed, and the governor pattern that determines the fuel injection amount is moved according to the corrected rotation speed to set the actual rotation speed as the target. Control to match the rotation speed.

Such idle speed control is carried out not only during normal idling, but also during idling up, in which the rotational speed is increased by a predetermined amount from that during normal idling in order to improve the effectiveness of the air conditioner, for example. Is executed similarly. The transition from the normal idle state to the idle up state or the return from the idle up state to the normal idle state is performed, for example, when the air conditioner is turned on and the idle up operation condition is satisfied, Is turned off and the idle-up stop condition is satisfied.

According to the above-mentioned technique, the rotational speed at the time of normal idle or idle up is operated regardless of variations among fuel injection pumps, magnitude of engine load, change over time, etc., and without using a special actuator. The target rotation speed can be controlled according to.

On the other hand, the applicant of the present invention, with respect to the above technique, gradually changes the estimated correction amount with time at the time of transition from the normal idle state to the idle up state or at the time of returning from the idle up state to the normal idle state. We proposed a changing structure (Japanese Patent Application No. 3-130007). With this configuration, a sudden change in the rotation speed at the time of idle-up operation or stop switching is suppressed, and the occupant is prevented from feeling a shock.

[0006]

However, with the technique for gradually changing the estimated correction amount, the actual rotation speed of the engine cannot be changed as intended. Because, at the time of idle up operation or stop switching,
When the estimated correction amount is gradually changed, the actual rotation speed gradually changes.However, the learning correction amount obtained from the deviation between the target rotation speed and the actual rotation speed temporarily increases, and the learning correction amount is integrated. This is because the integral control amount obtained by the above suddenly changes. As a result, even if the estimated correction amount is gradually changed, the fuel injection amount is increased or decreased at once, and the actual rotation speed is not gradually changed as intended. Therefore, at the same time when the idle-up operation condition or the stop condition is satisfied, the engine speed rapidly increases or decreases, causing a problem of shocking the occupant.

For example, in the case where the vehicle is equipped with an automatic transmission, if the operating condition for idle-up is satisfied by turning on the air conditioner while the vehicle is stopped in the drive range, the engine speed rapidly increases and the occupant receives the vehicle. It gave a feeling of popping out. Also, if the vehicle is a vehicle equipped with a manual transmission and the idle-up operating condition is satisfied while the vehicle is stopped,
The engine rotation speed increased sharply, deteriorating the vehicle's sensitivity.

The present invention has been made in view of these problems, and suppresses a rapid change in the rotation speed even when the idle-up operation condition is satisfied or the idle-up stop condition is satisfied, The purpose is to prevent passengers from feeling shock.

[0009]

In order to achieve such an object, the following constitution is adopted as a means for solving the above problems.

That is, as shown in FIG. 1, the rotation speed control apparatus for an internal combustion engine of the present invention includes a rotation speed detecting means M2 for detecting the rotation speed of the internal combustion engine M1 and the internal combustion engine M1.
Rotational speed adjusting means M3 for adjusting the rotational speed of the internal combustion engine and operating state detecting means M4 for detecting the operating state of the internal combustion engine M1.
And a target rotation speed setting means M5 for setting a target rotation speed according to the detected operating state, and a control amount based on the set target rotation speed and the rotation speed detected by the rotation speed detecting means M2. Is calculated and the rotation speed adjusting means M3 is controlled in accordance with the control amount to rotate the rotation speed to the target rotation speed. A mode change detecting means M7 for detecting a transition to the up mode or a return from the idle up mode to the normal idle mode as a mode change, and, when the mode change is detected by the mode change detecting means M7, a correction accompanying the mode change Control amount correction means M8 for calculating the amount and correcting the control amount calculated by the rotation speed control means M6 by the correction amount. Further, the correction amount gradually changing means M9 for gradually changing the correction amount calculated by the control amount correcting means M8 so that all or a part of the correction amount gradually changes with time, and the mode change detecting means M7. When a mode change is detected, a target rotation speed gradually changing means M10 for gradually changing the target rotation speed set by the target rotation speed setting means M5 so as to reach the target rotation speed by gradually changing with time. The point is that it is provided.

[0011]

In the internal-combustion-engine rotational speed control device of the present invention configured as described above, the target rotational speed according to the operating state of the internal combustion engine M1 is set by the target rotational speed setting means M5,
The rotation speed control means M6 calculates a control amount based on the target rotation speed and the rotation speed detected by the rotation speed detection means M2, and controls the rotation speed adjustment means M3 according to the control amount. , The rotation speed is shifted to the target rotation speed. Further, when the mode change detection means M7 detects the transition of the internal combustion engine M1 from the normal idle mode to the idle up mode or the return from the idle up mode to the normal idle mode as the mode change, the control amount correction means M8 causes A correction amount associated with the mode change is calculated, and the control amount calculated by the rotation speed control means M6 is corrected by the correction amount.

Moreover, the correction amount is adjusted by the correction amount gradual changing means M.
9, the whole amount or a part of the amount is gradually changed so as to gradually change with time, and when the mode change detection means M7 detects the mode change, the target rotation speed is gradually changed. The means M10 gradually changes with the passage of time and gradually changes to reach the target rotation speed.

As a result, when the mode is changed between the normal idle mode and the idle up mode,
The control amount calculated by the rotation speed control means M6 gradually increases or decreases with time, and the target rotation speed also gradually increases or decreases with time. Therefore, when the control amount is gradually changed and the actual rotation speed is gradually changed, the integrated control amount, which is the integrated value of the learning correction amount obtained from the deviation between the target rotation speed and the actual rotation speed, suddenly changes temporarily. Suppress things.

[0014]

Preferred embodiments of the present invention will be described below in order to further clarify the structure and operation of the present invention described above. FIG. 2 is a schematic configuration diagram of a diesel engine 1 equipped with a rotation speed control device for an internal combustion engine according to an embodiment of the present invention and peripheral devices thereof.

As shown in FIG. 2, the diesel engine 1
Is supplied with fuel from the fuel injection pump 2. First, the fuel injection pump 2 will be described. Fuel injection pump 2
Includes a drive gear 3 drivingly connected to the crankshaft 1a of the diesel engine 1 via a gear or the like. The fuel injection pump 2 is driven by the rotation of the drive gear 3, and the fuel is pressure-fed to the fuel injection nozzle 4 provided for each cylinder of the diesel engine 1 to inject the fuel.

A drive shaft 5 is connected to the drive gear 3. On the drive shaft 5, a vane type fuel feed pump 6 (deployed 90 ° in the figure)
A disk-shaped crank rotation angle pulsar 7 having a plurality of teeth is attached to the outer peripheral surface thereof. The base end portion (right end portion in the figure) of the drive shaft 5 is connected to the cam plate 8 via a coupling (not shown). A roller ring 9 is provided between the crank rotation angle pulsar 7 and the cam plate 8.
And a plurality of cam rollers 10 facing the cam face 8a of the cam plate 8 are attached to the roller ring 9. The cam plate 8 is constantly urged and engaged with the cam roller 10 by the spring 11.

A plunger 12 for fuel pressurization is integrally rotatably attached to the cam plate 8, and the rotational force of the drive shaft 5 is transmitted to the cam plate 8 via a coupling, whereby the cam plate 8 is rotated. And the plunger 12 is reciprocally driven in the left-right direction in the drawing while rotating. The plunger 12 is fitted into a cylinder 14 formed in the pump housing 13, and the plunger 12
A high-pressure chamber 15 is formed between the tip surface (right end surface in the figure) of the cylinder and the inner bottom surface of the cylinder 14. Intake grooves 16 and distribution ports 17 as many as the number of cylinders of the diesel engine 1 are formed on the outer periphery of the plunger 12 on the front end side. Also,
A distribution passage 18 and a suction port 19 are formed in the pump housing 13 so as to correspond to the suction groove 16 and the distribution port 17.

When the fuel feed pump 6 is driven based on the rotation of the drive shaft 5, fuel from a fuel tank (not shown) is supplied into the fuel chamber 21 through the fuel supply port 20. Further, in the suction stroke in which the plunger 12 moves (returns) to the left in the drawing and the high pressure chamber 15 is depressurized, one of the suction grooves 16 communicates with the suction port 19,
Fuel is introduced from the fuel chamber 21 into the high pressure chamber 15. on the other hand,
In the compression stroke in which the plunger 12 moves (forward) in the right direction in the drawing to pressurize the high-pressure chamber 15, the distribution passage 1
Fuel is pressure-fed from 8 to the fuel injection nozzle 4 for each cylinder for injection.

A spill passage 22 for connecting the high pressure chamber 15 and the fuel chamber 21 is formed in the pump housing 13,
An electromagnetic spill valve 23 is provided on the way. The electromagnetic spill valve 23 is a normally open type valve, and when the coil 24 is de-energized (off), the valve body 25 is opened and the high pressure chamber 15 is closed.
The fuel inside overflows into the fuel chamber 21. When the coil 24 is energized (ON), the valve body 25 is closed and the overflow of fuel from the high pressure chamber 15 to the fuel chamber 21 is stopped.

By controlling the energization timing of the electromagnetic spill valve 23, the electromagnetic spill valve 23 is controlled to open and close, and the overflow amount of fuel from the high pressure chamber 15 to the fuel chamber 21 is adjusted. Then, by opening the electromagnetic spill valve 23 during the compression stroke of the plunger 12, the fuel inside the high pressure chamber 15 is depressurized and the fuel injection from the fuel injection nozzle 4 is stopped. That is, even if the plunger 12 moves forward, the fuel pressure in the high pressure chamber 15 does not rise while the electromagnetic spill valve 23 is open, and fuel injection from the fuel injection nozzle 4 is not performed. Further, the amount of fuel injection from the fuel injection nozzle 4 is controlled by controlling the timing of opening and closing the electromagnetic spill valve 23 while the plunger 12 is moving forward.

Below the pump housing 13, there is provided a timer device (developed by 90 degrees) 26 for controlling the fuel injection timing. The timer device 26 is operated by hydraulic pressure, and has a timer housing 27, a timer piston 28 fitted in the timer housing 27, and a timer piston 28 in the low pressure chamber 29 on one side of the timer housing 27. It is composed of a timer spring 31 and the like that presses and urges the pressure chamber 30 on the side. Then, the timer piston 28 has the slide pin 32.
It is connected to the roller ring 9 via.

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 is determined by the equilibrium relationship between the fuel pressure and the urging force of the timer spring 31. Further, the position of the roller ring 9 is determined by determining the position of the timer piston 28, and the plunger 1 is moved through the cam plate 8.
2 reciprocating timing is determined.

In order to control the fuel pressure of the timer device 26, a timing control valve 33 is provided in the communication passage that connects the pressurizing chamber 30 and the low pressure chamber 29. The timing control valve 33 is an electromagnetic valve whose opening and closing is controlled by a duty-controlled energization signal, and the fuel pressure in the pressurizing chamber 30 is adjusted by the opening and closing control of the timing control valve 33. Then, the lift timing of the plunger 12 is controlled by the fuel pressure adjustment, and the fuel injection timing from each fuel injection nozzle 4 is adjusted.

A rotation speed sensor 35 composed of an electromagnetic pickup coil is attached to the upper part of the roller ring 9 so as to face the outer peripheral surface of the pulsar 7. Rotation speed sensor 3
When the protrusion of the pulsar 7 crosses, 5 detects the passage and outputs a timing signal indicating the rotation speed of the diesel engine 1. Further, the rotation speed sensor 35 outputs a reference timing signal at a constant timing with respect to the plunger lift.

Next, the diesel engine 1 will be described. In the diesel engine 1, the cylinder 41, the piston 42, and the cylinder head 43 form a main combustion chamber 44 corresponding to each cylinder. Each of the main combustion chambers 44 is connected to a sub combustion chamber 45 that is also provided corresponding to each cylinder. Fuel injected from each fuel injection nozzle 4 is supplied to each auxiliary combustion chamber 45. A well-known glow plug 46 as a start-up assist device is attached to each sub-combustion chamber 45.

An intake pipe 47 and an exhaust pipe 48 are connected to the diesel engine 1, and a return pipe 54 for returning a part of exhaust gas to the intake port 53 of the intake pipe 47 is connected to the exhaust pipe 48. It is provided. Reflux pipe 5
In the middle of 4, EGR valve 55 for adjusting the exhaust gas recirculation amount
The EGR valve 55 is opened / closed by controlling a vacuum switching valve (VSV) 56.

Further, in the middle of the intake pipe 47, there is provided a throttle valve 58 which is opened / closed in association with the depression amount of the accelerator pedal 57. Further, a bypass passage 59 is formed in parallel with the throttle valve 58, and a bypass throttle valve 61 whose opening and closing is controlled by an actuator 60 according to various operating states is provided in the middle of the bypass passage 59.
The actuator 60 is driven by the control of the two VSVs 62 and 63.

The electromagnetic spill valve 23, the timing control valve 33, the glow plug 46, and each VSV 5 provided on the diesel engine 1 and the fuel injection pump 2.
6, 62 and 63 are electronic control units (hereinafter, simply referred to as “ECU
ECU 70 electrically connected to each
The drive timings thereof are controlled by.

As a sensor for detecting the operating state of the diesel engine 1, the following sensors are provided in addition to the rotation speed sensor 35. That is, an intake air temperature sensor 72 that detects the temperature of the air taken into the intake pipe 47 via the air cleaner 71, and an accelerator opening sensor that detects the accelerator opening corresponding to the load of the diesel engine 1 from the opening / closing position of the throttle valve 58. 73, diesel engine 1
, A crank angle sensor 75 for detecting a rotation reference position of the crankshaft 1a (in this embodiment, a rotation position of the crankshaft 1a with respect to the top dead center of a specific cylinder), and a suction port 53. An intake pressure sensor 76 for detecting the supercharging pressure inside the vehicle, a vehicle speed sensor 77 for detecting the vehicle speed by turning on / off the reed switch 77b by a magnet 77a rotating in synchronization with the rotation of a gear of an automatic transmission (not shown), and the like are provided. ing.

Further, in addition to the various sensors, an air conditioner switch 78 for discriminating the operating state and the stopped state of the air conditioner, not shown, and a neutral switch 79 for indicating that the range position of the automatic transmission is neutral are provided. . Each of these sensors is E
The electromagnetic spill valve 23, the timing control valve 33, the glow plug 46, and the VS are respectively connected to the CU 70 and are based on the signals output from the respective sensors.
The drive control of V56, 62, 63 and the like is performed. The air conditioner is of a type that is automatically activated / deactivated according to the temperature in the room when the push button switch on the front of the instrument panel is turned on, and works in conjunction with the magnetic clutch of the compressor of the air conditioner. The air conditioner switch 78 determines its operating state.

Next, the configuration of the ECU 70 will be described with reference to the block diagram of FIG. As shown in FIG.
Reference numeral 70 denotes a central processing unit (CP that executes various arithmetic processing.
U) 80, read-only memory (ROM) 81 in which a predetermined control program, maps, etc. are stored in advance, CPU 8
A random access memory (RAM) 82a for temporarily storing the operation result of 0, a backup RAM 82b for storing previously stored data, an input port 83 and an output port 84 are connected as a logical operation circuit by a bus 85.

The input port 83 has an intake air temperature sensor 72,
The accelerator opening sensor 73, the water temperature sensor 74, and the intake pressure sensor 76 are connected via the buffers 86, 87, 88, 89, the multiplexer 90, and the A / D converter 91. Further, an air conditioner switch 78 and a neutral switch 79 are connected to the input port 83 by a buffer 9
2, 93 are connected. Further, the rotation speed sensor 35, the crank angle sensor 75, and the vehicle speed sensor 77.
Are connected via the waveform shaping circuit 94. And
The CPU 80 reads the detection signal of each sensor input via the input port 83 as an input value.

The output port 84 has a driving circuit 96,
The electromagnetic spill valve 23, the timing control valve 33, the glow plug 46, the VSV 56, 62, 63, etc. are connected via 97, 98, 99, 100, 101. The CPU 80 controls the electromagnetic spill valve 23, the timing control valve 33, the glow plug 46, and the VSV based on the input values read from the sensors and switches.
56, 62, 63 etc. are suitably controlled.

Next, the ECU 70 constructed as described above.
The main routine of the engine speed control executed by the CPU 80 will be described in detail with reference to the flowchart of FIG. It should be noted that this processing routine is executed by interruption every predetermined time.

When the processing is started, the CPU 80 first reads the engine rotation speed NE detected by the rotation speed sensor 35 (step S110). Next, the read engine rotation speed NE and the integral control amount NII and the estimated correction amount NIP obtained by the interrupt routine described later.
Therefore, the corrected rotational speed NEI is calculated based on the following equation (1).
SC is calculated (step S120). NEISC = NE- (NIP + NII) (1)

After that, the corrected rotational speed NEISC and the accelerator opening ACC detected by the accelerator opening sensor 73 are detected.
Based on and, the fuel injection amount Q is obtained by map search or calculation (step S130). As a result, the governor pattern on the map appears, and NIP + N in the rotation speed axis direction.
It means that only II is translated. Then, the fuel injection time corresponding to the fuel injection amount Q is output to the drive circuit 96 of the electromagnetic spill valve 23 (step S140). As a result, the electromagnetic spill valve 23 is driven to open for the fuel injection time. After that, the procedure returns to "return" and this main routine is repeatedly executed.

Next, 8 is applied to the above main routine.
The interrupt routine executed by the CPU 80 at each msec interrupt will be described in detail with reference to the flowchart of FIG. This 8 msec interrupt routine is performed by the integral control amount NII and the estimated correction amount N used in step S120 of FIG.
IP is calculated.

As shown in FIG. 5, when the processing is started, the CPU 80 first determines whether or not the idle-up control execution condition is satisfied, based on whether or not the air conditioner is in an operating state (step). S200). Specifically, this determination is made based on the output signal from the air conditioner switch 78.

When it is determined in step S200 that the air conditioner is in the operating state, a process of calculating the estimated correction amount NIP in the idle-up state based on the following equation (2) is performed (step S210). NIP = NIFOF + NIPON + NIPAC (2) That is, the predetermined offset amount NIPOF and the estimated correction amount N corresponding to the load variation due to the operation of the air conditioner.
IPON and the estimated correction amount NIPAC corresponding to the increase in the rotation speed required to enhance the cooling capacity of the air conditioner
The expected correction amount NIP is calculated by adding and.

The offset amount NIPOF and the expected correction amount NIPON corresponding to the load fluctuation amount are respectively predetermined values. On the other hand, the estimated correction amount NIPAC corresponding to the idle-up amount takes an arbitrary value obtained by another interrupt routine described later.

On the other hand, if it is determined in step S200 that the air conditioner is not in operation, that is, is in a stopped state, a process for calculating the expected correction amount NIP in the normal idle state is performed (step S220). Specifically, as shown in the following equation (3), a predetermined offset amount NI
The estimated correction amount NIP is calculated by adding the POF and the estimated correction amount NIPAC corresponding to the increase in the rotation speed due to the operation of the air conditioner. NIP = NIFOF + NIPAC (3)

The expected correction amount N for idle up
The IPAC normally takes a value of 0 when the idle-up stop condition in which the air conditioner is stopped is satisfied, but takes an arbitrary value only for a predetermined time after switching from the idle-up state to the idle-up stop state. The estimated correction amount NIPAC for the idle-up is obtained by another interrupt routine described later.

After execution of step S210 or S220, a process for calculating the target rotational speed offset amount NTRG0 is subsequently performed (step S230). This target rotation speed NTRG0 is calculated based on, for example, the cooling water temperature THW of the diesel engine 1 detected by the water temperature sensor 74, the shift range of the torque converter (D range or N range), the operating state of the air conditioner, and the like. Specifically, a map in which the target rotation speed NTRG0 is set according to the states of these events is prepared in the ROM 81 in advance, and the map is searched to obtain the map.

After that, the target rotational speed offset amount N
Add the target rotation speed correction amount NTRAC to TRG0,
The target rotation speed NTRG is calculated (step S24).
0). The target rotational speed correction amount NTRAC referred to here is
It is a gradual change component of the target rotation speed calculated by another interrupt routine described later, and takes a value of 0 to 100 [rpm].

Subsequently, the engine speed NE detected by the speed sensor 35 is read (step S25).
0). Then, it is determined whether the operating state of the diesel engine 1 is the idle state (step S260). This determination is made based on whether or not all the following conditions are satisfied. The conditions include, for example, that the accelerator opening ACC detected by the accelerator opening sensor 73 is 0, the vehicle speed detected by the vehicle speed sensor 77 is 0, and the shift range of the automatic transmission is N range or D range. That is, the idle switch is on and the starter is off, and the idle switch has been on for more than a predetermined time. When it is determined in step S260 that the vehicle is in the idle state, the following processing is performed.

First, a deviation ΔNE between the target rotation speed NTRG calculated in step S240 and the engine rotation speed NE read in step S250 is calculated (step S).
270). Then, based on the deviation ΔNE, the learning correction amount Δ
NII is calculated (step S280). The learning correction amount ΔNII is calculated by a map prepared in advance in the ROM 81 or by calculation. Then, the learning correction amount ΔNII calculated in step S280 is added to the previous integrated control amount NII to calculate the current integrated control amount NII (step S290).

After executing step S290, "return"
Then, the processing of this interrupt routine is temporarily terminated. On the other hand, if it is determined in step S260 that the vehicle is not in the idle state, steps S270 to S290 are skipped,
After that, exit to "return".

Next, the interrupt routine executed by the CPU 80 at an interrupt every 50 msec with respect to the main routine shown in FIG. 4 will be described in detail with reference to the flowchart of FIG. This 50msec interrupt routine is shown in Fig. 5.
The estimated correction amount NIPAC for idle-up used in steps S210 and S220 and the target rotational speed correction amount NTRAC used in step 240 are calculated.

As shown in FIG. 6, when the processing is started, the CPU 80 first determines whether or not the idle-up control execution condition is satisfied, based on whether or not the air conditioner is in an operating state (step). S300). Here, if it is determined that the air conditioner is in the operating state, the following processing is executed.

First, a predetermined update amount ΔNIPAC is added to the estimated correction amount NIPAC for the idle-up calculated at the time of the previous process execution (which has been cleared to 0 in advance when the CPU 80 is started), and this idle-up amount is added. A process of calculating the estimated correction amount NIPAC of is performed (step S310). Next, the upper limit value NIPACMX of the estimated correction amount for idle-up is calculated (step S32).
0). Here, a process of calculating the upper limit value NIPACMX according to the cooling water temperature THW detected by the water temperature sensor 74 and the like is performed.

Subsequently, the expected correction amount for idle-up calculated in step S310 is compared with the upper limit value NIPACMX calculated in step S320 (step S330). If it is determined that the estimated correction amount NIPAC for idle-up is larger than the upper limit value NIPACMX, the upper limit value NIPACMX is set as the estimated correction amount NIPAC for idle-up (step S34).
0). On the other hand, if it is determined in step S330 that the estimated correction amount NIPAC for idle-up is less than or equal to the upper limit value NIPACMX, step S340 is skipped and the estimated correction amount NIPAC for idle-up is left as it is.

Thereafter, a predetermined update amount ΔNTRA is added to the target rotational speed correction amount NTRAC calculated at the time of the previous process execution (which is previously cleared to 0 when the CPU 80 is started).
A process of calculating the target rotational speed correction amount NTRAC of this time by adding C is performed (step S350). Next, it is determined whether or not the calculated target rotation speed correction amount NTRAC is larger than a predetermined rotation speed (in the present embodiment, the upper limit value NIPACMX calculated in step S320) (step S360), and it is determined here that it is larger. Then, the target rotation speed correction amount NTRAC is set to the upper limit value NIPAMX. On the other hand, the target rotation speed correction amount NTRAC is the upper limit value N
If it is determined to be equal to or lower than IPACMX, step S3
70 is skipped and the target rotation speed correction amount NTRAC is left as it is. After that, the procedure returns to "return" to end the processing of this routine once.

On the other hand, if it is determined in step S300 that the air conditioner is not in operation, the following processing is executed.
First, a predetermined update amount ΔNIPAC is calculated from the estimated correction amount NIPAC for idle-up calculated at the time of the previous processing execution.
By subtracting the expected correction amount NI for this idle up
A process of calculating PAC is performed (step S380).
Next, it is determined whether or not the calculated expected correction amount for idle-up is smaller than the value 0 (step S390).
If it is determined to be small, the estimated correction amount NIPAC for idle-up is set to 0 (step S400).
On the other hand, if it is determined in step S390 that the estimated correction amount NIPAC for idle-up is 0 or more,
The step S340 is skipped, and the estimated correction amount NIPAC for idle-up is left as it is.

After that, a predetermined update amount ΔNTRA is calculated from the target rotational speed correction amount NTRAC calculated during the previous processing execution.
A process of subtracting C and calculating the target rotational speed correction amount NTRAC this time is performed (step S410). Next, it is determined whether or not the calculated target rotation speed correction amount NTRAC is smaller than the value 0 (step S420), and if it is determined to be smaller, the target rotation speed correction amount NTRAC is set to 0 [rp].
m]. On the other hand, the target rotation speed correction amount NTRAC is 0
If it is determined that the above is the case, the step S430 is skipped and the target rotational speed correction amount NTRAC is left as it is. After that, the procedure returns to "return" to end the processing of this routine once.

By repeating the above main routine and both interrupt routines, the actual engine speed N
E is feedback-controlled to the target rotation speed NTRG. Hereinafter, how the engine speed NE and various control amounts change with time will be described based on the timing chart of FIG. 7.

As shown in the figure, when the air conditioner is switched from the stopped state to the operating state (time t1), the estimated correction amount NIP is only the estimated correction amount NIPON corresponding to the load change due to the load change caused by the operation of the air conditioner. It grows up all at once. Next, the estimated correction amount NI
P gradually increases by ΔNIPAC (time t1 to t
2) When the gradually changed size becomes the estimated correction amount NIPACMX for idle-up (time t2), the estimated correction amount NIP holds that value thereafter. On the other hand, time t
After 1, the target rotation speed NTRG is the offset amount NTRG.
When the value of 0 gradually increases by ΔNTRAC and the gradually changed magnitude reaches the upper limit value NIPACMX, the target rotation speed NTRG holds the value thereafter.

The expected correction amount NI between the times t1 and t2
When only P is gradually changed, the actual rotation speed gradually changes. Therefore, the integral control amount NII obtained by integrating the learning correction amount obtained from the deviation between the target rotation speed and the actual rotation speed is
In the figure, it suddenly changes as shown by the broken line. On the other hand, according to the present embodiment, as described above, the target rotation speed NTRG is also gradually changed at the same time as the estimated correction amount NIP.
The deviation between the target rotation speed NTRG and the actual rotation speed NE becomes small, and the integrated control amount NII does not temporarily change suddenly.

Since the fuel injection amount Q is determined according to the integrated control amount NII, the engine speed (actual speed) NE has conventionally sharply increased as shown by the broken line in the figure. According to the present embodiment, since the integrated control amount NII does not change suddenly temporarily, the engine rotation speed NE does not increase sharply but gradually increases to settle at the target rotation speed NTRG at idle-up.

On the other hand, when the air conditioner is switched from the operating state to the stopped state (time t3), the estimated correction amount NIP is adjusted from the estimated correction amount at the time of idling up due to the load change due to the load change caused by the stop of the air conditioner. Only the amount NIPON decreases at once. Next, the estimated correction amount NIP gradually decreases by ΔNIPAC with time (time t3 to t4), and the offset amount NIPOF.
(The estimated correction amount NIPAC for idle-up becomes a value 0: time t4). After that, the offset amount N
Holds the value of IPOF. On the other hand, after this time t3, the target rotation speed NTRG gradually decreases by ΔNTRAC, and when the offset amount NTRG0 is reached, the target rotation speed NTRG is reduced.
TRG holds the offset amount NTRG0.

The estimated correction amount NI between the times t3 and t4
When P is gradually changed, the integral control amount NII is conventionally set in the same manner as when the air conditioner is switched from the operating state to the stop state.
Changes suddenly as shown by the broken line in the figure. On the other hand, according to the present embodiment, since the target rotation speed NTRG is also gradually changed at the same time as the expected correction amount NIP, the deviation between the target rotation speed and the actual rotation speed becomes small, and the integrated control amount NII is reduced.
Does not change suddenly. Therefore, conventionally, the engine rotation speed (actual rotation speed) NE sharply decreases as shown by the broken line in the figure, but according to the present embodiment, the integral control amount NII does not temporarily change suddenly. The engine speed NE does not decrease sharply but gradually decreases to a target speed NTRG during normal idle (700 [rpm] in the example shown in FIG. 7).

As described above, in this embodiment, when the normal idle state is shifted to the idle up state, the estimated correction amount NIPAC for the idle up and the target rotational speed NTR are set.
By gradually increasing G and time, the sudden change of the integrated control amount NII is suppressed and the engine speed NE is gradually increased with time. Therefore, even if the idle-up operation condition such as the operation of the air conditioner is satisfied, the rotation speed does not suddenly change. As a result, the occupant does not feel a shock due to unnecessary vibration of the diesel engine 1. In particular, it is possible to prevent the vehicle from feeling popping out when the air conditioner is operating while the vehicle is stopped.

Further, in the present embodiment, when the idle-up state is returned to the normal idle state, the estimated correction amount NIPAC for the idle-up and the target rotation speed NTRG are gradually decreased with the lapse of time, whereby the integral control amount is increased. N
By suppressing the sudden change of II, the engine speed NE is gradually decreased with time. Therefore, even if the idle-up stop condition such as the stop of the air conditioner is satisfied, the rotation speed does not suddenly decrease. As a result, the occupant does not feel a shock due to unnecessary vibration of the diesel engine 1.

Further, since the change of the integrated control amount NII is suppressed, other control such as control of the EGR correction amount based on the integrated control amount NII can be performed with high accuracy.

In this embodiment, the rotational speed is gradually increased with the passage of time from the normal idle state to the idle up state, and the rotational speed is gradually increased with the passage of time from the idle up state to the normal idle state. However, any one of these controls may be omitted.

Further, in this embodiment, the estimated correction amount N when the mode is changed between the idle-up state and the normal idle state.
Although the idle-up portion NIPAC in the IP is configured to be gradually changed, it may be configured to gradually change both the idle-up portion NIPAC and the load fluctuation portion NIPON instead.

Further, in the present embodiment, the idle-up operating condition is set when the air conditioner is in the operating state. However, in place of this, when the power steering is fully set up, the idle-up operating condition is required. May be Furthermore, although the rotational speed control of the diesel engine has been described in the present embodiment, the present invention can be applied to a gasoline engine, in which case the rotational speed of the engine may be adjusted by the fuel injection amount, Alternatively, the rotation speed of the engine may be adjusted according to the intake air amount.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to such an embodiment and can be implemented in various modes without departing from the scope of the present invention. Of course, you can.

[0068]

As described above, in the engine speed control system for an internal combustion engine of the present invention, the engine speed is controlled when the normal idle state is shifted to the idle up state or when the idle up state is returned to the normal idle state. It is possible to suppress a sudden change in the integrated control amount that shifts to the target rotation speed. Therefore, a sudden change in the rotation speed can be suppressed, and the occupant will not feel a shock.

Further, since the change of the integrated control amount is suppressed, various controls such as the control of the EGR correction amount performed based on the integrated control amount can be performed with high accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a rotation speed control device for an internal combustion engine of the present invention.

FIG. 2 is a schematic configuration diagram of a diesel engine 1 equipped with a rotation speed control device for an internal combustion engine that is an embodiment of the present invention and peripheral devices thereof.

FIG. 3 is a block diagram showing an electrical configuration of a control system centered on an ECU 70.

FIG. 4 is a flowchart showing a main routine of engine rotation speed control processing executed by a CPU 80 of the ECU 70.

FIG. 5 is a flowchart showing an interrupt routine executed every 8 msec by the CPU 80.

FIG. 6 is a flowchart showing an interrupt routine executed every 50 msec by the CPU 80.

FIG. 7 is a timing chart showing an operation based on the above-described various routines executed by the CPU 80.

[Explanation of symbols]

 M1 ... Internal combustion engine M2 ... Rotational speed detection means M3 ... Rotational speed adjustment means M4 ... Operating state detection means M5 ... Target rotational speed setting means M6 ... Rotational speed control means M7 ... Mode change detection means M8 ... Control amount correction means M9 ... Correction Quantity gradual change means M10 ... Target rotation speed gradual change means 1 ... Diesel engine 2 ... Fuel injection pump 4 ... Fuel injection nozzle 23 ... Electromagnetic spill valve 35 ... Rotation speed sensor 70 ... ECU 73 ... Accelerator opening sensor 74 ... Water temperature sensor 78 ... Air conditioner switch 79 ... Neutral switch 80 ... CPU 81 ... ROM NE ... Engine rotation speed NEISC ... Corrected rotation speed NII ... Integral control amount NIP ... Expected correction amount NIPON ... Expected correction amount for load fluctuation NIPAC ... Expected correction for idle up Quantity NTRG ... Target rotation speed NTRAC ... Target rotation speed Correction amount Q ... fuel injection amount

Claims (1)

[Claims] 1. A rotation speed detecting means for detecting a rotation speed of an internal combustion engine, a rotation speed adjusting means for adjusting a rotation speed of the internal combustion engine, an operating state detecting means for detecting an operating state of the internal combustion engine, Target rotation speed setting means for setting a target rotation speed according to the detected operating state, and a control amount based on the set target rotation speed and the rotation speed detected by the rotation speed detection means, By controlling the rotation speed adjusting means according to the control amount, a rotation speed control means for shifting the rotation speed to the target rotation speed, and a shift or idle from a normal idle mode of the internal combustion engine to an idle up mode. A mode change detecting means for detecting a return from the up mode to the normal idle mode as a mode change, and a mode change detecting means for detecting the mode change. And a control amount correction means for correcting the control amount calculated by the rotation speed control means based on the correction amount when the control amount is corrected. Correction amount gradual changing means for gradually changing the calculated correction amount so that all or a part of the correction amount gradually changes with time; and the target rotation when the mode change is detected by the mode change detecting means. A rotation speed control device for an internal combustion engine, comprising: a target rotation speed gradually changing means for gradually changing a target rotation speed set by a speed setting means so as to reach the target rotation speed by gradually changing with time.