JP2003138966A - Engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the rotation convergence of the rotational frequency of an engine when a load is applied in the idling period. SOLUTION: In the idling period, during a set period of time just after a load (an air-conditioner load, a power steering load, or a running range load) is applied to the engine 1 when the drastic increase of the load on the engine 1 is expected, each correction quantity (the air-conditioner correction quantity KAC, the power steering correction quantity KPW, or the running range correction quantity KD) is set at a value suitable for the transition time when the load is drastically increased and relatively higher than the value when the load is constant after the set period elapses, and each target rotational frequency correction quantity NUPAC, NUPPW, or NUPD is set at a value suitable for the transition time when the load is drastically increased and relatively higher than the value when the load is constant after the set period elapses. Accordingly, the engine torque is accurately increased in response to the drastic increase of the load just after the load is applied to the engine, so that the engine stall and variation of the engine rotation can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device, and more particularly to an engine control device for improving the rotational convergence of the engine speed when a load is applied during idling.

[0002]

2. Description of the Related Art Conventionally, during idling, a target throttle opening degree is increased / decreased according to a load applied to an engine, and a throttle valve is drive-controlled so that an engine speed at load application becomes a target idle speed. Various proposals have been made regarding techniques for converging. For example,
For example, in Japanese Patent Laid-Open No. 7-197828, an external load is determined by using an engine output torque obtained from the engine speed and a throttle opening and a load torque stored in advance for driving an external load. A technique is disclosed in which an engine speed is converged to a target idle speed by setting a target throttle opening such that an output torque sufficient to offset the load torque is further output when applied.

[0003]

However, as in the technique disclosed in the above-mentioned Japanese Patent Laid-Open No. 7-197828, the goal is to further output the output torque that simply cancels the load applied to the engine. In the control for setting the throttle opening, it becomes difficult to converge the engine speed early at the transition of the sudden increase in load immediately after the load is applied to the engine (see the broken line in FIG. 5), and the engine speed falls. Or engine stall may occur.

In view of the above circumstances, it is an object of the present invention to provide an engine control device capable of improving the rotational convergence of the engine speed when a load is applied during idling.

[0005]

In order to solve the above-mentioned problems, the invention according to claim 1 is to provide:
The target throttle opening is feedback-corrected by comparing the engine speed with the target speed, and the target throttle opening is compared with the actual throttle opening. The load correction amount for correcting the target throttle opening according to the load is set within a set time from when the load is applied to when the load reaches a steady state, relative to a value after the set time has elapsed. The load correction means for setting a high value, and the target rotation speed correction for setting the target rotation speed relatively higher than the value after the lapse of the above-mentioned set time within the set time from the time when the load is applied to the steady state And means.

According to a second aspect of the present invention, in the first aspect of the present invention, the load correction means increases the load correction amount according to an increase in the load applied to the engine.

That is, according to the first aspect of the invention, the load correction amount based on the load is a value after the set time elapses during the set time until the load applied to the engine reaches a steady state when the engine is idle. Is set to a value relatively higher than the above to correct the target throttle opening, and the target speed based on the load is set to a value higher than the value after the set time has elapsed, so that the engine speed when the load is turned on is increased. To improve the convergence of.

In this case, according to the second aspect of the invention, the load correction amount is increased according to the increase of the load applied to the engine.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The drawings relate to an embodiment of the present invention. FIG. 1 is a schematic configuration diagram of an engine control system, FIG. 2 is a flowchart of a throttle valve control routine, and FIGS.
FIG. 6 is a flowchart of a load correction amount / target rotation speed setting routine, and FIG. 6 is a time chart showing an example of changes in the load correction amount and target rotation speed due to load application during idling.

In FIG. 1, reference numeral 1 is an engine,
The present embodiment is an in-cylinder injection engine that directly injects fuel into a cylinder and burns an air-fuel mixture by spark ignition.
The engine 1 is a horizontally opposed four-cylinder gasoline engine in the figure. Cylinder heads 2 are provided on the left and right banks of the cylinder block 1a, and an intake port 3 and an exhaust port 4 are provided for each cylinder of each cylinder head 2. And are formed.

The engine 1 of the present embodiment is a four-valve engine having two intake valves and two exhaust valves for each cylinder, and one of the intake manifolds 5 communicating with each of the two intake ports 3 is provided. The branch pipe is provided with a swirl control valve 6 for generating a swirl flow in the combustion chamber in a low / medium load operation region to improve the combustion efficiency of the engine, and the upstream manifold of each branch pipe of the intake manifold 5 is installed. A throttle valve 8 is provided in the air chamber 7, which is a part of the engine.

Further, the upstream side of the air chamber 7 is connected to an intake pipe 10 via an electronically controlled throttle body having a throttle valve 8 and a throttle actuator 9 for driving the throttle valve 8, and the intake pipe 10 is connected to the intake pipe 10. An air box 12 for storing an air cleaner is communicated with the upstream side, and fresh air is taken in through an air intake chamber 13.

Further, an exhaust pipe 15 is connected to each exhaust port 4 of each cylinder of the engine 1 through an exhaust manifold 14, and a catalyst having a three-way catalyst at a confluence portion of the exhaust pipe 15 from both left and right banks. Converter 16 is interposed,
Further, a catalytic converter 17 having a NOx storage catalyst is provided downstream of the catalytic converter 16 to provide a muffler 18
Is in communication with.

A blow-by gas passage 23 communicating with the crank chamber of the engine 1 extends from the cylinder block 1a side and is branched midway to communicate one with the intake pipe 10 upstream of the throttle valve 8 and the other with the other. The blow-by gas control valve 24 communicates with the downstream side of the throttle valve 8. Further, a fresh air introduction passage 25 for introducing fresh air into the crankcase extends from the intake pipe 10 upstream of the throttle valve 8 and communicates with the cylinder head 2 of each bank.

An electronically controlled EGR control valve for controlling the EGR amount by a control signal from the electronic control unit 100 is provided in the middle of an exhaust gas recirculation (EGR) passage 26 which connects the air chamber 7 and the exhaust port 4. 27 is interposed.

An in-cylinder injector 28 is exposed to the combustion chamber 1b of each cylinder of the engine 1. Further, the injector 28 for in-cylinder injection serves as an injector that is used as an auxiliary when starting at low temperature. An intake pipe injection injector 29 for injecting fuel into the intake pipe is arranged upstream of the swirl control valve 6 of the intake manifold 5 for each bank.

Fuel tank 3 for storing fuel for in-cylinder injector 28 and intake pipe injector 29
0 is provided with an in-tank type fuel pump 31 having a built-in fuel regulator, and a fuel line 32 extending from a discharge port of the fuel pump 31 is branched into two via a fuel filter 33, one of which is for each bank. It is connected to each intake pipe injection injector 29, and the other is connected to the high-pressure fuel pump unit 35.

The high-pressure fuel pump unit 35 includes a high-pressure fuel pump driven via the cam shaft of the engine 1, a high-pressure regulator for adjusting the discharge pressure of the high-pressure fuel pump to the injection pressure for in-cylinder injection, and the like. A fuel return line 36 to the fuel tank 30 and a high-pressure line 37 that communicates with a fuel distribution pipe 38 for each bank that distributes fuel to the in-cylinder injector 28 of each cylinder are provided.

A fuel pressure switching solenoid valve 39 is connected to the high pressure line 37 for in-line air purging, and a fuel return line 41 of a pressure regulator 40 connected to the fuel pressure switching solenoid valve 39 is connected to the high pressure fuel pump. The fuel return line 36 from the unit 35 is joined and connected to the fuel tank 30.

The fuel pressure switching solenoid valve 39 is opened at the time of air purging, and by bypassing the high pressure line 37 to the fuel tank 30 via the pressure regulator 40, the fuel pressure in the high pressure line 37 is lowered to reduce the fuel flow rate. The air in the high pressure line 37 or the evaporative gas is quickly discharged by increasing the volume.

Further, in order to release the vaporized gas in the fuel tank 30, a purge passage 42 is extended from the upper portion of the fuel tank 30 as shown by a broken line in the figure, and a fuel leak due to a vehicle overturning should be performed. It is communicated with a canister 45 having an adsorbing portion made of activated carbon or the like through a rollover valve 43 and a two-way valve 44 for preventing the above. The downstream side of the canister 45 in the purge passage 42 is connected to the air chamber 7 via a canister purge control valve 46 for controlling the amount of evaporated fuel purged from the canister 45.

On the other hand, an ignition plug 47 for exposing the discharge electrode at the tip to the combustion chamber 1b is provided for each cylinder of the cylinder head 2 of the engine 1, and the ignition plug 47 for each cylinder is provided with
An ignition coil 48 containing an igniter is connected in series. Further, in the cam sprocket that drives each intake cam shaft in each cylinder head 2, a well-known method is used in which the intake cam pulley and the intake cam shaft are relatively rotated to continuously change the rotational phase of the intake cam shaft with respect to the crank shaft. A hydraulically driven variable valve timing actuator 49 is provided. The variable valve timing actuator 49 is drive-controlled by hydraulic pressure via an oil flow control valve 50 that operates by a drive signal from the electronic control unit 100.

Next, the arrangement of sensors for detecting the operating condition will be described. The intake air temperature sensor 51 faces the air box 12 that stores the air cleaner, and the intake pipe 1
Immediately downstream of the 0 air box 12, a thermal type intake air amount sensor 5 using a hot wire or a hot film is used.
2 is installed.

A throttle sensor 53 is connected to the throttle valve 8 provided in the throttle body.
An accelerator sensor 55 is connected to the accelerator pedal 54 via a cable in order to detect the depression amount of the accelerator pedal 54 as an output request from the driver for controlling the engine 1.

In the fuel distribution pipe 38 of one bank,
A fuel pressure sensor 56 for detecting the fuel pressure is attached, and an air-fuel ratio sensor 57 for detecting the air-fuel ratio in the exhaust gas in the entire operating range is provided on the upstream and downstream sides of the catalytic converter 16 having a three-way catalyst, respectively. An air temperature sensor 58 is provided, and an O2 sensor 59 for detecting the oxygen concentration in the exhaust gas passing through the NOx storage catalyst is provided downstream of the catalytic converter 17 having the NOx storage catalyst.

On the other hand, the cylinder block 1a of the engine 1
The knock sensor 60 is attached to the cylinder block 1
A cooling water temperature sensor 62 is exposed to the cooling water passage 61 that connects the left and right banks of a. Further, a crank angle sensor 64 is provided on the outer periphery of a crank rotor 63 that is axially attached to the crank shaft of the engine 1, and the crank angle sensor 64 is 1/1
A cylinder discrimination sensor 65 is provided on the back surface of the intake cam pulley that rotates twice.
Are opposite to each other. Further, a cam position sensor 66 for detecting the intake cam position, which is the valve timing control information, is provided on the outer circumference of the cam rotor fixed to the rear end of the intake cam shaft.
Are opposite to each other. It should be noted that in the present embodiment, the cylinder discrimination sensor 65 is provided only in one bank.

The sensors and actuators in the engine 1 described above are connected to an electronic control unit (ECU) 100 composed of a microcomputer and peripheral circuits, and signals from the sensors are processed by the ECU 100 so that the actuators are controlled. It is driven and the engine 1 is electronically controlled. The ECU 100 of this embodiment is composed of a main control unit section 100a and an ETC control unit section 100b. In the main control unit section 100a, air-fuel ratio control including fuel injection control, ignition timing control, EGR control, variable valve timing control, etc. The ETC control unit section 100b exclusively performs electronic control of the throttle valve 8 via the throttle actuator 9.

The main control unit section 100a is connected to a dedicated injector drive unit 101 for driving the in-cylinder injector 28, and an injector driver for turning on / off the power supply to the injector drive unit 101. The relay coil of the relay 102 and the relay coil of the fuel pump relay 103 for turning on and off the power source to the fuel pump 31 are connected, and the ignition power source is supplied through the relay contact of the ignition relay 104.

As the sensors connected to the main control unit 100a, the above-mentioned sensors, that is, the intake air temperature sensor 51, the intake air amount sensor 52, the accelerator sensor 55, the fuel pressure sensor 56, the air-fuel ratio sensor 5 are used.
7, an exhaust gas temperature sensor 58, an O2 sensor 59, a knock sensor 60, a cooling water temperature sensor 62, a crank angle sensor 64, a cylinder discrimination sensor 65, a cam position sensor 66, a master bag pressure sensor 67, and the like. Further, the main control unit section 100a includes a refrigerant pressure sensor 70 for detecting a refrigerant pressure PAC of an air conditioner (not shown) and an O air conditioner for the air conditioner.
An air conditioner switch 71 for performing N / OFF switching, a power steering switch that is turned on by determining the operation of the power steering when the power steering oil pressure exceeds a predetermined value by steering and the drive load of the power steering oil pump increases above a predetermined value. 72 and an inhibitor switch 73 for detecting the range position of a select lever (not shown) are connected.

As the actuators connected to the main control unit 100a, the above-mentioned actuators, that is, the swirl control valve 6, the EGR control valve 27, the intake pipe injection injector 29, and the fuel pressure switching solenoid valve 39. , A canister purge control valve 46, an igniter built in the ignition coil 48, an oil flow control valve 50 for hydraulically driving the variable valve timing actuator 49, and the like. However, the in-cylinder injector 28 is connected to a dedicated injector drive unit 101 and is drive-controlled by a control command from the main control unit section 100a to the injector drive unit 101.

On the other hand, the ETC control unit 100b is connected to the relay coil and the relay contact of the ETC power supply relay 105 as well as to the throttle actuator 9 and the throttle sensor 53 in order to turn on and off the ETC power supply. , Main control unit section 100
In order to make the throttle opening according to the control command from a,
The throttle actuator 9 is driven based on the signal from the throttle sensor 53. That is, the throttle valve 8 throttles the actual throttle opening to the target throttle opening THVTGT based on the comparison between the target throttle opening THVTGT (described later) and the actual throttle opening detected by the throttle sensor 53. The drive is controlled via the actuator 9.

The ECU 100 calculates various control amounts on the basis of operating states obtained by processing signals from various sensors and switches, and outputs drive signals corresponding to the controlled amounts to various actuators to set the operating states. The control is performed so that the air-fuel ratio in the corresponding combustion mode is always an appropriate air-fuel ratio. In such engine control, the ECU 100 sets the basic target average effective pressure PeB based on the engine speed NE and the accelerator position AP, and sets the target throttle opening THVTGT based on the basic target average effective pressure PeB. At that time, the correction amount (KTW) based on the engine cooling water temperature TW is set, and the air conditioner operation, the power steering operation, and the N range of the automatic transmission are changed to D
A load correction amount (KAC, KPW, KD) based on each load applied to the engine 1 in accordance with the shift to the range, etc. is set, and the basic target average effective pressure P is set by these load correction amounts.
By correcting eB, the target throttle opening THVTG
Correct T. Further, when the engine 1 is idle, the target rotational speed NTGT is corrected based on each load, and the target throttle opening THVTGT is feedback-corrected so that the engine rotational speed NE becomes the target rotational speed NTGT.

That is, the ECU 100 has the functions of the load correction means and the target rotation speed correction means according to the present invention. Specifically, the functions of the respective means are realized by the flowcharts of FIGS. 2 to 5.

The throttle valve control processing by the ECU 100 will be described below with reference to the flowcharts of FIGS.

FIG. 2 shows a throttle valve control routine executed at a predetermined cycle of, for example, 10 msec.
In step S101, the engine speed NE detected based on the signal from the crank angle sensor 64 and the accelerator position AP detected by the accelerator sensor 55 are used as parameters to refer to the table with interpolation calculation to determine the basic target average effective pressure. Set PeB.

Next, in step S102, the water temperature correction amount KTW for the basic target average effective pressure PeB is set using the engine cooling water temperature TW detected by the cooling water temperature sensor 62 as a parameter.

Next, at step S103, each target throttle opening is corrected in response to a change in engine load due to air conditioner operation, steering (power steering operation), and shift of the automatic transmission from N range to D range. Air conditioner correction amount KAC, which is load correction amount, power steering correction amount KP
The W and D range correction amount KD is read. Here, each of these load correction amounts is set in a load correction amount / target rotation speed setting routine described later.

In step S104, the basic target average effective pressure PeB is corrected by the water temperature correction amount KTW and each load correction amount (KAC, KPW, KD) to calculate the target average effective pressure Pe (Pe = PeB + KTW + KAC +).
KPW + KD).

After that, in step S105, the target average effective pressure Pe and the engine speed NE are used as parameters to refer to the table with interpolation calculation to determine the target throttle opening TH.
Set VTGT.

In the following step S106, it is checked whether the engine 1 is in the idle state. In this case, in step S106, for example, when the vehicle speed VSP = 0 and the accelerator release is detected by the accelerator sensor 55, it is determined that the engine 1 is in the idle state.

When it is determined in step S106 that the engine 1 is not in the idle state, step S11
After jumping to 1 and setting the target throttle opening THVTGT set in step S105 as the final target throttle opening THVTGT, the routine exits.

On the other hand, when it is determined in step S106 that the engine 1 is in the idle state, step S10
7, the target engine speed NTGT of the engine 1 is read out. Here, the target rotation speed NTGT is set in a load correction amount / target rotation speed setting routine described later.

Next, at step S108, the target rotation speed NT
The deviation ΔN of the engine speed NE with respect to GT is calculated (ΔN = NTGT-NE), and in step S109, the feedback correction amount THVC is set by referring to a table using the deviation ΔN as a parameter. Here, this embodiment is
As the feedback control of the idle speed, the feedback correction amount is set by integral control, but, for example, proportional integral (PI) control, proportional derivative (PD) control, proportional integral derivative (PID) control may be adopted. .

Thereafter, in step S110, the target throttle opening THVTGT set in step S105 described above is set.
Is corrected by the feedback correction amount THVC (THVTG
T ← THVTGT + THVC), in step S111,
After setting the corrected target throttle opening THVTGT as the final target throttle opening THVTGT, the routine exits.

Here, each load correction amount (KAC, KPW, K used when correcting the basic target average effective pressure PeB).
D) and the target engine speed NTGT of the engine 1 are shown in FIG.
It is set by the load correction amount / target rotation number setting routine shown in FIG.

This routine is executed every predetermined cycle of 10 msec, for example, and steps S201 to S2 are executed.
By the process of 13, the air conditioner correction amount KAC, the air conditioner O
A target revolution speed correction amount NUPAC for N hours is set. First,
In step S201, it is checked whether the air conditioner switch 71 is turned on. Then, if it is determined in step S201 that the air conditioner switch 71 is off and the load (air conditioner load) by the compressor of the air conditioner is not applied to the engine 1, step S201
In step 202, the air conditioning correction amount KAC is set to zero corresponding to no correction (KAC ← 0).

In subsequent steps S203 and S204, a flag FLGAC indicating that the air conditioner (compressor) operation load is stable and the air conditioner operation is steady, and the time from when the air conditioner is turned on until the air conditioner load is in a steady state are set. Both the count values CNTAC to be clocked are cleared (FLGAC ← 0, CNTAC ← 0), and step S2
In 05, after setting the target rotation speed correction amount NUPAC for correcting the target rotation speed when the air conditioner is ON to zero corresponding to no correction (NUPAC ← 0), step S21
Go to 4.

Accordingly, when the air conditioner switch 17 is off and the air conditioner (compressor) is stopped, the air conditioner correction amount K
The target rotation correction amount NUPAC when AC and the air conditioner are both turned on is set to zero, and no correction is made by the correction amounts KAC and NUPAC.

On the other hand, if it is determined in step S201 that the air conditioner switch 71 is turned on and the air conditioner load is applied to the engine 1, step S20 is performed.
6, the process proceeds to step S206 and step S207 to determine whether or not it is a transient time of a sudden load increase until the air conditioner load after the air conditioner is turned on reaches a steady state. That is, the value of the flag FLGAC is referred to in step S206, and when FLGAC = 0, the process proceeds to step S207, the count value CNTAC is compared with a preset value C1 that can be regarded as a transient time of a sudden increase in air conditioner load, and the air conditioner It is checked whether or not a set time (for example, 1 to several seconds) determined by the set value C1 has passed since the switch 71 was turned on.

Then, in steps S206 and S207,
If FLGAC = 0 and CNTAC <C1, and during a transient increase in the air conditioner load from the start of the air conditioner operation when the air conditioner switch 71 is turned on until the set time determined by the set value C1 elapses, the process proceeds to step S208, and the count value CNTAC Is counted up (CNTAC ← C
NTAC + 1), then in step S209, the refrigerant pressure P
Table TBL with AC as the parameter of air conditioner load
With reference to KAC1, an air conditioner correction amount KAC suitable for a transition of a sudden increase in air conditioner load due to the start of air conditioner operation is set. Here, the table value of the table TBLKAC1 is obtained in advance by experiments, simulations, etc., and the target average effectiveness is dealt with in response to a transient increase in the air conditioner load with the refrigerant pressure PAC as a parameter to prevent engine stall and engine speed fluctuation. It is set to an optimum value for increasing the pressure Pe (target throttle opening THVTGT) and stored in the memory of the ECU 100. In this case, the air conditioner correction amount KAC set in the table TBLKAC1 is set to a high value according to the rise of the refrigerant pressure PAC, and the air conditioner correction amount KAC set by the table TBLACN to be described later when the air conditioner operation is stationary after the set time has elapsed. Is set to a value relatively higher than.

Then, in step S210, the target revolution speed correction amount NUPAC is set by a proper set value NUPAC1 which is suitable for increasing the target revolution speed in a transient state of a sudden increase in air conditioner load accompanying the start of operation of the air conditioner. It proceeds to S214. Here, the set value NUPAC1 is obtained in advance by experiments, simulations, etc., and the ECU 10
It is stored as fixed data in memory 0. It should be noted that the set value NUP suitable for the transition of the sudden increase in air conditioner load
AC1 is set to a value relatively higher than a set value NUPACN that is suitable when the air conditioner operation is stationary, which will be described later.

On the other hand, in step S206, FLGAC =
1 or CNTAC ≧ C1 in step S207
When the air conditioner operation is stable in which the load by the air conditioner (compressor) is stable after the elapse of the set time determined by the set value C1, the process proceeds to step S211, and the flag FLGA is set.
After setting C (FLGAC ← 1), step S21
Go to 2.

In step S212, the table TBLKAC is set with the refrigerant pressure PAC as an air conditioner load parameter.
With reference to N, the air conditioner correction amount KAC suitable for the air conditioner load when the air conditioner is operating normally is set. Here, the table value of the table TBLKACN is obtained by experiments or simulations performed in advance, and similarly, the target average effective pressure Pe corresponding to the steady state of the air conditioner load is maintained in order to maintain the engine speed with the refrigerant pressure PAC as a parameter. It is set to an optimum value for increasing (target throttle opening THVTGT) and stored in the memory of the ECU 100. In this case, the air conditioner correction amount KAC set in the table TBLKACN is set to a high value as the refrigerant pressure PAC rises.

Then, in step S213, the target rotational speed correction amount NUPAC is set to an appropriate set value NU so as to increase the target rotational speed by adapting to the air conditioner load when the air conditioner is operating normally.
After setting by PACN, the process proceeds to step S214.
Here, the set value NUPACN is obtained in advance by experiments, simulations, etc., and is stored as fixed data in the memory of the ECU 100.

When the process proceeds from step S205, step S210, or step S213 to step S214,
Through the processing of steps S214 to S226, the power steering correction amount KPW, the target rotation speed correction amount NUPPW during power steering ON.
Is set.

First, in step S214, it is checked whether or not the power steering switch 72 is turned on by steering. Then, in step S214, if it is determined that the power steering switch 72 is turned off and the amount of load (power steering load) due to the operation of the power steering oil pump to the engine 1 is equal to or less than the predetermined value, the process proceeds to step S215. , Power steering correction amount K
Set PW to zero corresponding to no correction (KPW ←
0).

Then, in steps S216 and S217,
A flag FLGPW indicating that the power steering (power steering oil pump) is in a stable power steering operation in a stable operating state, and until the power steering load is in a steady state after the power steering switch 72 is turned on by steering. Both the count value CNTPW for measuring the time of are cleared (FLGPW ← 0, CNTP
W ← 0), power steering O in step S218
After setting the target rotation speed correction amount NUPPW for increasing and correcting the target rotation speed at N (zero) corresponding to no correction (NUPPW ← 0), the process proceeds to step S227.

Therefore, the power steering switch 72
When is OFF, power steering correction amount KPW, power steering O
Both the N-hour target rotation speed correction amount NUPPW are set to zero, and no correction is made by the correction amounts KPW and NUPPW.

On the other hand, if it is determined in step S214 that the power steering switch 72 is turned on and the power steering load of a predetermined value or more is applied to the engine 1, the process proceeds to step S219, and the determinations in steps S219 and S220 are made. Thus, it is checked whether or not the power steering load after the power steering is turned on is in a transient state of a sudden increase in load until it reaches a steady state. That is, in step S219, the value of the flag FLGPW is referred to, and FL
When GPW = 0, the process proceeds to step S220, the count value CNTPW is compared with a preset setting value C2 that can be regarded as a transient time of a rapid increase in power steering load, and the setting is determined by the setting value C2 after the power steering switch 72 is turned on. It is checked whether or not a time (for example, 1 to several seconds) has passed.

Then, in steps S219 and S220,
When the flag FLGPW = 0 and CNTPW <C2, the power steering load suddenly increases from when the power steering switch 72 is turned on by the start of steering until the set time determined by the set value C2 elapses, the process proceeds to step S221.
Count up the count value CNTPW (CNTPW
(← CNTPW + 1), and in the subsequent step S222, the power steering correction amount KPW is set by the set value KPW1 adapted at the transition of the power steering load sudden increase. Here, the set value KP
W1 is obtained in advance by experiments, simulations, etc., and is used to increase the target average effective pressure Pe (target throttle opening THVTGT) in response to a transient power load sudden increase in order to prevent engine stall and engine speed fluctuation. It is set to an optimum value and stored as fixed data in the memory of the ECU 100. The set value KPW1 suitable for a transient power steering load sudden increase is set to a value relatively higher than a set value KPWN suitable for a steady power steering operation described later.

Then, in step S223, the target rotational speed correction amount NUPPW is set appropriately so that the target rotational speed can be increased by adapting the target rotational speed correction amount NUPPW during a transition of a sudden increase in power steering load.
After setting by 1, proceed to step S227. Here, the set value NUPPW1 is obtained in advance by experiments, simulations, etc., and is stored as fixed data in the memory of the ECU 100. Further, a set value NUPPW1 suitable for a transition of the power steering load sudden increase is set to a value relatively higher than a set value NUPPWN suitable for a steady power steering operation described later.

On the other hand, in step S219, FLGPW =
1 or CNTPW ≧ C2 in step S220
When the power steering operation is in a steady state in which the power steering load state is stable after the lapse of the set time determined by the set value C2, the process proceeds to step S224, sets the flag FLGPW (FLGPW ← 1), and then proceeds to step S225.

In step S225, the power steering correction amount K
PW is a set value KPWN that is suitable when the power steering load is steady.
Set to. Here, the set value KPWN is obtained in advance by experiments, simulations, etc., and is optimal for increasing the target average effective pressure Pe (target throttle opening THVTGT) in response to steady power steering load in order to maintain the engine speed. And is stored as a fixed data in the memory of the ECU 100.

Then, in step S226, the target rotational speed correction amount NUPPW is set by the appropriate set value NUPPWN that can be adjusted when the power steering load is steady and the target rotational speed can be increased, and then the process proceeds to step S227. Here, the set value NUPPWN is obtained in advance by experiments, simulations, etc. and is similarly stored as fixed data in the memory of the ECU 100.

When the process proceeds from step S218, step S223, or step S226 to step S227, the D range correction amount KD and the D range target rotational speed correction amount NUPD are set by the processing of steps S227 to S239.

First, in step S227, it is checked based on the signal from the inhibitor switch 73 whether or not the range position of the select lever is the D range (running range). Then, when it is determined that the load by the torque converter (D range load) is not applied to the engine 1 in the non-driving range, the process proceeds to step S228, and the D range correction amount KD is set to zero corresponding to no correction (KD). ←
0).

Then, in steps S229 and S230,
The flag FLGD indicating that the operating load by the torque converter after the traveling range transition is stable and the traveling range load is in a steady state, and until the traveling range load reaches a steady state after shifting from the non-traveling range to the traveling range Clear the count value CNTD that counts the time of (F
LGD ← 0, CNTD ← 0), and in step S231, after setting the target rotation speed correction amount NUPD for correcting the target rotation speed after the shift to the running range to zero corresponding to no correction (NUPD ← 0), It proceeds to step S240.

Therefore, when the load from the transmission side is not acting due to the non-driving range, the D range correction amount K
Both the target rotation speed correction amount NUPD in the D and D ranges are set to zero, and there is no correction by the correction amounts KD and NUPD.

On the other hand, in step S227, the select lever is shifted to the traveling range, and the engine 1
When the driving range load is applied to step S23
2, the process proceeds to step S232 and step S233, and it is determined whether or not the load of the traveling range after transitioning to the traveling range is in a transient state of rapid load increase to a steady state. That is, in step S232, the flag FL
Referring to the value of GD, when FLGD = 0, step S2
In step 33, the count value CNTD is compared with a preset setting value C3 that can be regarded as a transient time of a sudden increase in the running range load, and the set value C is set after shifting from the non-running range to the running range.
It is checked whether or not a set time (for example, 1 to several seconds) determined by 3 has passed.

Then, in steps S232 and S233,
If FLGD = 0 and CNTD <C3, and during the transition of the sudden increase in the running range load after the transition from the non-running range to the running range until the elapse of the set time determined by the set value C3, the process proceeds to step S234, and the count value is increased. The CNTD is counted up (CNTD ← CNTD + 1), and in a succeeding step S235, the traveling range correction amount KD is set by the set value KD1 adapted at the transition of the sudden load increase accompanying the traveling range transition. Here, the set value KD1 is obtained in advance by experiments, simulations, etc., and in order to prevent engine stall and engine speed fluctuation, the target average effective pressure P corresponding to the transition of a sudden increase in load accompanying the travel range shift.
It is set to an optimum value for increasing e (target throttle opening THVTGT) and is stored as fixed data in the memory of the ECU 100. The set value KD1 suitable for a transition of a sudden increase in the running range load is set to a value relatively higher than a set value KDN suitable for a steady running range load described later.

Then, in step S236, the target rotational speed correction amount NUPD is set by a proper set value NUPD1 which is adapted to increase the target rotational speed in a transient state of a rapid increase in the traveling range load accompanying the traveling range shift. Step S2
Proceed to 40. The set value NUPD1 is obtained in advance by experiments, simulations, or the like and is stored as fixed data in the memory of the ECU 100. The set value NUPD1 suitable for a transient transient load increase in the driving range is a setting suitable for a steady running range load described later. It is set to a value relatively higher than the value NUPDN.

On the other hand, in step S232, the flag FLGD is set.
= 1 or CNTD ≧ C3 in step S233
When the traveling range load is steady after the lapse of the set time determined by the set value C3, the process proceeds to step S237, the flag FLGD is set (FLGD ← 1), and then the step S
Proceed to 238.

In step S238, the travel range correction amount KD is set to the set value KDN which is suitable when the travel range load is steady.
Set to. Here, the set value KDN is obtained in advance by experiments, simulations, etc., and is used to increase the target average effective pressure Pe (target throttle opening THVTGT) in response to a steady running range load in order to maintain the engine speed. It is set to an optimum value and stored as fixed data in the memory of the ECU 100.

Then, in step S239, the target rotation speed correction amount NUPD is set to a proper set value NUPDN that can be increased when the running range load is steady and the target rotation speed can be increased, and then the process proceeds to step S240. Here, the set value NUP
The DN is obtained in advance by experiments, simulations, etc., and is similarly stored as fixed data in the memory of the ECU 100.

When the process proceeds from step S231, step S236, or step S239 to step S240,
The basic target rotation speed NTGTB is set by referring to the table with the engine cooling water temperature TW as a parameter with interpolation calculation.

Then, in step S241, the basic target engine speed NTGTB is added to each target engine speed correction amount NUPAC, N.
After setting UPW and NUPD to set the target rotation speed NTGT (NTGT ← NTGTB + NUPAC + NUP
PW + NUPD), exit routine.

Next, an example of the operation of the above control will be described with reference to the time chart shown in FIG.

As shown in FIG. 6, when idle,
When the transition from OFF to ON of the air conditioner switch 71 is detected, the ECU 100 causes the air conditioner correction to be performed during the set time immediately after the air conditioner switch 71 is turned on (that is, the set time determined by the set value C1) in which a rapid increase in the air conditioner load is assumed. The amount KAC and the target rotational speed correction amount NUPAC are set to values that are suitable for a transient increase in air conditioner load and that are relatively higher than the values during steady operation of the air conditioner after the set time has elapsed. Then, when the air conditioner operation is stationary after the lapse of the set time, the air conditioner correction amount KAC and the target rotation speed correction amount NUPAC are set to values that are suitable when the air conditioner load is stationary. At that time, the air conditioner correction amount KAC should be increased in order to increase the throttle opening in response to the higher load of the air conditioner compressor as the refrigerant pressure PAC increases.
It is set to a high value according to the rise of the refrigerant pressure PAC.

Therefore, at the time of transition due to a sudden increase in load at the start of operation of the air conditioner, the air conditioner correction amount KAC suitable for the transient condition
As a result, the throttle opening is increased, and the target rotation speed is increased by the target rotation speed correction amount NUPAC, so that the engine torque is accurately increased in response to a sudden increase in load when the air conditioner starts operating, and engine stall and engine rotation fluctuations occur. To be prevented.

Further, when the transition of the power steering switch 72 from OFF to ON is detected, the power steering switch 72O is expected to have a rapid increase in power steering load.
During the set time immediately after N (that is, the set time determined by the set value C2), the power steering correction amount KPW and the target rotational speed correction amount NUPPW are values that are suitable at the transition of the power steering load sudden increase, and after the set time has elapsed. Set to a value that is relatively higher than the value when the power steering operation is stationary. Then, when the power steering operation is stationary after the lapse of the set time, the power steering correction amount KPW and the target rotation speed correction amount NUP are set.
PW is set to a value that is suitable when the power steering load is steady.

Therefore, during a transition due to a sudden increase in the power steering oil pump drive load due to steering, the throttle opening is increased by the power steering correction amount that matches this and the target rotation speed is increased by the target rotation speed correction amount NUPPW. The engine torque is accurately increased in response to a sudden increase in the power steering oil pump drive load due to steering, and engine stall and engine speed fluctuation are prevented.

Similarly, when the shift of the shift lever from the non-traveling range to the traveling range is detected, the vehicle travels during the set time (that is, the set time determined by the set value C3) in which a sudden increase of the running range load is expected. The range correction amount KD and the target rotational speed correction amount NUPD are set to values that are suitable for the transient transition of the sudden increase in the traveling range load and that are relatively higher than the values for the steady traveling range load after the set time has elapsed. Then, when the traveling range load is steady after the elapse of the set time, the traveling range correction amount KD and the target rotation speed correction amount NUPD are set to values that are suitable when the traveling range load is steady.

Therefore, during a transition in which the load rapidly increases due to the shift from the non-running range to the running range, the throttle opening is increased by the running range correction amount KD adapted to this and the target rotation speed by the target rotation speed correction amount NUPD is also increased. By increasing the engine torque, the engine torque is appropriately increased in response to a sudden increase in load accompanying the shift from the non-running range to the running range, and engine stall and engine speed fluctuation are prevented.

According to the present embodiment, each load (air conditioner load, power steering load, running range load) during idling.
When the load suddenly increases immediately after the engine is put into the engine 1, the load is corrected by the load and the target rotation speed correction amount is set higher than the steady-state value to perform throttle control, so that the engine stall or the engine rotation is stopped. It is possible to prevent the fluctuation of the engine speed and improve the convergence and stability of the engine speed when the load is applied.

At that time, the refrigerant pressure PAC (air conditioner load)
As the drive load of the air conditioner compressor increases as the value increases, the air conditioner correction amount KAC is set to a high value in accordance with the increase in the refrigerant pressure PAC. Therefore, the engine speed when the air conditioner load is turned on is effectively increased. The rotational convergence of can be improved.

In the present embodiment, the example in which the throttle opening during idling is corrected based on the air conditioner load, the power steering load, and the driving range load has been described, but the present invention is not limited to this, and the air conditioner is not limited to this. The throttle opening during idling may be corrected based on at least one of the load, the power steering load, and the traveling range load.

Further, in the present embodiment, an example in which only the air conditioner correction amount KAC is variably set according to the air conditioner load (refrigerant pressure PAC) when setting the load correction amount has been described, but the present invention is not limited to this. Not, for example,
The power steering correction amount KPW may be variably set according to the power steering load (driving load of the power steering oil pump).

The present invention can also be applied to the well-known electric load correction when the drive load of the generator suddenly increases due to an increase in power consumption, as the load correction during idling.

The present invention is not limited to the in-cylinder injection engine, but can be applied to the in-cylinder injection engine (intake system injection engine).

[0090]

As described above, according to the present invention, at the time of idling, the load correction amount and the target rotational speed within the set time until the load applied to the engine becomes a steady state are set after the set time elapses. By setting the value higher than the value and performing the throttle control, it is possible to improve the rotation convergence of the engine speed when the load is applied.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an engine control system.

FIG. 2 is a flowchart of a throttle valve control routine.

FIG. 3 is a flowchart (part 1) of a load correction amount / target rotation speed setting routine.

FIG. 4 is a flowchart of a load correction amount / target rotation speed setting routine (part 2).

FIG. 5 is a flowchart of a load correction amount / target rotation speed setting routine (part 3).

FIG. 6 is a time chart showing an example of changes in the load correction amount and the target rotation speed when the load is applied during idling.

[Explanation of symbols]

1 ... Engine 100 ... ECU (load correction means, target rotation speed correction means) C1, C2, C3 ... Set value (set time) KAC ... Air conditioner correction amount (load correction amount) KPW ... Power steering correction amount (load correction amount) KD ... Travel range correction amount (load correction amount) NE ... Engine speed NTGT ... Target speed THVTGT ... Target throttle opening

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3G065 AA04 AA06 AA07 CA15 DA04                       EA03 FA12 GA00 GA05 GA08                       GA09 GA16 GA27 GA33 GA41                       GA46 HA06 HA21 HA22 JA04                       JA11 KA02                 3G084 BA03 BA05 CA03 DA05 EB12                       EC01 EC03 FA18 FA33                 3G301 HA01 JA03 KA07 LA01 ND03                       NE23 PA17Z PE01Z PF11Z                       PF13Z PF14Z

Claims (2)

[Claims] 1. When the engine is idle, the target throttle opening is feedback-corrected by comparing the engine speed and the target speed, and the throttle valve is driven and controlled by comparing the target throttle opening and the actual throttle opening. In the engine control device, the load correction amount for correcting the target throttle opening according to the load applied to the engine is set within the set time from the application of the load to the steady state. The load correction means for setting the value relatively higher than the value after the passage of time, and the target rotation speed within the set time from when the load is applied to when the load reaches a steady state is higher than the value after the set time has elapsed. A control device for an engine, comprising: a target rotational speed correction means for setting a relatively high value. 2. The engine control device according to claim 1, wherein the load correction means increases the load correction amount in accordance with an increase in the load applied to the engine.