DESCRIPTION

Control Apparatus and Control Method for Powertrain

Technical Field

The present invention relates to a control apparatus and a control method for a powertrain, particularly to a technique for controlling a drive source using a target value of an output value converted from the target revolution number.

Background Art

Conventionally, there is a known engine in which a value of output torque and the like are determined by an opening position of a throttle valve (hereinafter, also referred to as a throttle opening position) or the like. In general, the throttle opening position is actuated so as to chiefly correspond to a position of an accelerator pedal (hereinafter, also referred to as an accelerator pedal position). However, when the throttle opening position and the accelerator pedal position always chiefly correspond to each other, drive force of a vehicle or the like is not easily controlled irrespective of an intention of a driver for example in the case where an action of the vehicle is disordered. Therefore, there is a vehicle provided with an electronic throttle valve actuated by an actuator in an engine so as to be capable of controlling output torque and the like not depending on the accelerator pedal position. In the vehicle provided with the electronic throttle valve, it is possible to set target engine torque based on the action of the vehicle or the like in addition to the accelerator pedal position and control the engine so that actual engine torque is the set target engine torque. Japanese Patent Laying-Open No. 2006-297993 discloses a drive force control apparatus provided with a first target drive force calculating unit for calculating first target drive force based on control input for an accelerator pedal of a driver, a second target drive force calculating unit for calculating second target drive force so that a

vehicle keeps a fixed vehicle speed or a predetermined relative distance or a relative speed relationship with regard to an object around the vehicle, an intention judging unit for judging an intention of acceleration/deceleration of the driver, an adjusting unit for adjusting the first target drive force and the second target drive force based on the drive force while in consideration of the intention of acceleration/deceleration of the driver judged in the intention judging unit, and a drive force controlling unit for controlling a drive force generation apparatus based on the target drive force adjusted in the adjusting unit.

According to the drive force control apparatus described in Japanese Patent Laying-Open No. 2006-297993, it is possible to make adjustment based on the drive force while properly making adjustment in accordance with the intention of acceleration/deceleration of the driver. It should be noted that in Japanese Patent Laying-Open No. 2006-297993, the drive force is converted into the target engine torque. However, in the case of making adjustment based on the drive force as in the drive force control apparatus described in Japanese Patent Laying-Open No. 2006- 297993, for example when a transmission is in a neutral state, it is not possible to give reactive force from the transmission to the engine. Therefore, the engine revolution number is unstable. Consequently, output torque of the engine, that is, the drive force is easily changed, and control is not easily performed based on the drive force.

Disclosure of the Invention

An object of the present invention is to provide a control apparatus and a control method for a powertrain capable of improving control accuracy. A control apparatus for a powertrain according to one aspect is a control apparatus for a powertrain provided with a drive source and a transmission coupled to the drive source. This control apparatus comprises a first setter that sets a first target value of an output value of the drive source, the output value being different from a

revolution number, a second setter that sets the target revolution number, a converter that converts the target revolution number into a second target value of the output value of the drive source, a third setter that sets a third target value based on the first target value and the second target value, and a controller that controls the drive source in accordance with the third target value.

According to this configuration, the first target value of the output value of the drive source (such as output torque or drive force) is set and the target revolution number is also set. The target revolution number is converted into the second target value of the output value of the drive source. The third target value is set based on the first target value of the output value and the second target value converted from the target revolution number. The drive source is controlled in accordance with the third target value. Accordingly, in the case where the drive source is preferably controlled so as to satisfy a demand on the output value of the drive source, the drive source can be controlled based on the output value. In the case where the drive source is preferably controlled so as to satisfy a demand on the output shaft revolution number, the drive source can be controlled based on the output shaft revolution number. As a result, it is possible to improve the control accuracy.

Preferably, the third setter sets a smaller value of the first target value and the second target value as the third target value. According to this configuration, the smaller value of the first target value and the second target value is set as the third target value. Accordingly, it is possible to set the target value of the output value so that output of the drive source does not easily become excessive. When switching between a state where the first target value is set as the third target value and a state where the second target value is set as the third target value, it is possible to maintain continuity of the third target value.

Further preferably, the first setter sets the first target value so as to be larger than the second target value in a predetermined operation state.

According to this configuration, the first target value of the output value of the

drive source is set so as to be larger than the second target value in a predetermined operation state. For example, in the case where there is no demand on the output value of the drive source, the first target value is set so as to be larger than the second target value in order to set the second target value as the third target value. Accordingly, in the case where control based on the output shaft revolution number is obviously preferable, it is possible to unexecute control based on the output value. Therefore, it is possible to further improve the control accuracy of the drive source.

Further preferably, the second setter sets the target revolution number so that the second target value is larger than the first target value in a predetermined operation state. According to this configuration, the target revolution number is set so that the second target value is larger than the first target value in a predetermined operation state. For example, in the case where there is no demand on the output shaft revolution number of the drive source, the target revolution number is set so that the second target value is larger than the first target value in order to set the first target value as the third target value. Accordingly, in the case where the control based on the output value is obviously preferable, it is possible to unexecute the control based on the output shaft revolution number. Therefore, it is possible to further improve the control accuracy of the drive source.

Further preferably, the control apparatus for the powertrain further includes a determiner that determines whether an input shaft and an output shaft of the transmission are shut off or coupled to each other. The first setter sets the first target value so as to be larger than the second target value in the case where it is determined that the input shaft and the output shaft of the transmission are shut off. The second setter sets the target revolution number so that the second target value is larger than the first target value in the case where it is determined that the input shaft and the output shaft of the transmission are coupled to each other.

According to this configuration, in the case where it is determined that the input shaft and the output shaft of the transmission are shut off, the first target value is set so

as to be larger than the second target value. Accordingly, in a state where reactive force cannot be given to the output shaft of the drive source and in the case where the control based on the output shaft revolution number is obviously preferable, it is possible to unexecute the control based on the output value. In the case where it is determined that the input shaft and the output shaft of the transmission are coupled to each other, the target revolution number is set so that the second target value is larger than the first target value. Accordingly, in a state where the reactive force can be given to the output shaft of the drive source and in the case where the control based on the output value is obviously preferable, it is possible to unexecute the control based on the output shaft revolution number. Therefore, it is possible to further improve the control accuracy of the drive source.

Further preferably, the determiner determines that the input shaft and the output shaft of the transmission are shut off in the case where one of a neutral range and a parking range is selected as a shift range of the transmission. According to this configuration, it is possible to accurately determine whether or not the input shaft and the output shaft of the transmission are shut off based on the fact that any of the neutral range and the parking range is selected as the shift range.

Further preferably, the determiner determines whether the input shaft and the output shaft of the transmission are shut off or coupled to each other based on the input shaft revolution number and the output shaft revolution number of the transmission.

According to this configuration, it is possible to accurately determine whether the input shaft and the output shaft of the transmission are shut off or coupled to each other based on the input shaft revolution number and the output shaft revolution number of the transmission. Further preferably, the output value is output torque. The converter calculates first output torque required for maintaining the output shaft revolution number of the drive source, calculates second output torque required for changing the output shaft revolution number of the drive source to the target revolution number, and converts the

target revolution number into the second target value by adding the second output torque to the first output torque.

According to this configuration, it is possible to accurately convert the target revolution number into the second target value of the output torque by adding the second output torque required for changing the output shaft revolution number of the drive source to the target revolution number to the first output torque required for maintaining the output shaft revolution number of the drive source.

Further preferably, a hydraulic coupling is provided between the drive source and the transmission. The converter calculates the first output torque in accordance with a capacity coefficient of the hydraulic coupling and the output shaft revolution number of the drive source.

According to this configuration, it is possible to accurately calculate the first output torque required for maintaining the output shaft revolution number of the drive source based on the capacity coefficient of the hydraulic coupling and the output shaft revolution number of the drive source.

Further preferably, the converter calculates the first output torque in accordance with torque due to resistance determined depending on the output shaft revolution number of the drive source.

According to this configuration, it is possible to accurately calculate the first output torque based on the torque due to the resistance determined depending on the output shaft revolution number of the drive source.

Further preferably, the converter calculates the second output torque in accordance with inertia from the drive source to the input shaft of the transmission.

According to this configuration, the second output torque required for changing the output shaft revolution number of the drive source to the target revolution number is calculated in accordance with the inertia from the drive source to the input shaft of the transmission. Accordingly, it is possible to calculate the second output torque used for converting the target revolution number into the second target value of the output

torque based on the inertia accurately corresponding to inertia to be considered in a state where the reactive force cannot be given to the output shaft of the drive source. Therefore, the second output torque accurately corresponding to a situation in which the control based on the output shaft revolution number is preferable can be obtained. Consequently, it is possible to accurately convert the target revolution number into the target value of the output torque.

Further preferably, the control apparatus for the powertrain further includes a corrector that corrects the second target value in accordance with a difference between the target revolution number and the actual output shaft revolution number of the drive source.

According to this configuration, it is possible to reduce the difference between the target revolution number and the actual output shaft revolution number by feedback control of correcting the second target value in accordance with the difference between the target revolution number and the actual output shaft revolution number of the drive source.

Brief Description of the Drawings

Fig. 1 is a schematic configuration diagram showing a powertrain of a vehicle.

Fig. 2 is a skeleton diagram showing a planetary gear unit of an automatic transmission.

Fig. 3 is a working table of the automatic transmission.

Fig. 4 is a diagram showing an oil hydraulic circuit of the automatic transmission.

Fig. 5 is a function block diagram of an ECU.

Fig. 6 is a diagram showing a controller that converts the target engine revolution number into second target engine torque.

Fig. 7 is a table showing a control state of the automatic transmission.

Fig. 8 is a table showing an actual state of the automatic transmission.

Fig. 9 is a table showing a value set as the target engine revolution number NET.

Fig. 10 is a diagram showing a power train driver model.

Fig. 11 is a map and a model used for setting target engine revolution number NET.

Fig. 12 is a diagram showing target engine revolution number NET.

Best Modes for Carrying Out the Invention

An embodiment of the present invention will be described below with reference to the drawings. In the following description, the same parts are given the same reference numerals. Names and functions thereof are all the same. Therefore, a detailed description thereof will not be repeated.

With reference to Fig.1, a vehicle with a control apparatus according to the embodiment of the present invention installed will be described. This vehicle is an FR (Front engine Rear drive) vehicle. It should be noted that this vehicle may be a vehicle other than the FR vehicle. The vehicle includes an engine 1000, an automatic transmission 2000, a torque converter 2100, a planetary gear unit 3000 constituting part of automatic transmission 2000, an oil hydraulic circuit 4000 constituting part of automatic transmission 2000, a propeller shaft 5000, a differential gear 6000, rear wheels 7000, and an ECU (Electronic Control Unit) 8000. Engine 1000 is an internal combustion engine for combusting an air-fuel mixture of fuel injected from an injector (not shown) and the air in a combustion chamber of a cylinder. A piston in the cylinder is pushed down by the combustion and a crankshaft is rotated. An auxiliary machine 1004 such as an alternator and an air conditioner is driven by engine 1000. Output torque of engine 1000 (engine torque TE) is changed in accordance with an actuated amount of an electronic throttle valve 8016, that is, a throttle opening position or the like. It should be noted that a motor may be used as a power source instead of or in addition to engine 1000. Alternatively, a diesel engine may be used. In the diesel engine, output torque is changed in accordance with the

valve opening time of the injector (the actuated amount), that is, a fuel injection amount.

Automatic transmission 2000 is coupled to engine 1000 with torque converter 2100 interposed therebetween. Automatic transmission 2000 implements a desired gear so as to shift the revolution number of the crankshaft to a desired revolution number. It should be noted that a CVT (Continuously Variable Transmission) for continuously changing a gear ratio may be installed instead of the automatic transmission implementing a gear. Further, another automatic transmission configured by an constant-meshing type gear shifted by an oil hydraulic actuator or an electric motor may be installed. Torque outputted from automatic transmission 2000 is transmitted to right and left rear wheels 7000 through propeller shaft 5000 and differential gear 6000.

A position switch 8006 of a shift lever 8004, an accelerator pedal position sensor 8010 of an accelerator pedal 8008, an air flow meter 8012, a throttle opening position sensor 8018 of electronic throttle valve 8016, an engine speed sensor 8020, an input shaft speed sensor 8022, an output shaft speed sensor 8024, an oil temperature sensor 8026, and a water temperature sensor 8028 are connected to ECU 8000 with a harness and the like interposed therebetween.

A position of shift lever 8004 (a shift position) is detected by position switch 8006, and a signal representing a detection result is transmitted to ECU 8000. The gear of automatic transmission 2000 is automatically implemented in response to the position of shift lever 8004. A driver may select a manual shift mode in which the driver can select any gear in accordance with operations of the driver.

Accelerator pedal position sensor 8010 detects a position of accelerator pedal 8008 and transmits a signal representing a detection result to ECU 8000. Air flow meter 8012 detects an amount of air to be taken in engine 1000 and transmits a signal representing a detection result to ECU 8000.

Throttle opening position sensor 8018 detects an opening position of electronic throttle valve 8016 adjusted by an actuator and transmits a signal representing a

detection result to ECU 8000. The amount of air to be taken in engine 1000 is adjusted by electronic throttle valve 8016.

It should be noted that the amount of air to be taken in engine 1000 may be adjusted by a variable valve lift system of changing the lift amount or opening/closing phase of an inlet valve (not shown) or an outlet valve (not shown) instead of or in addition to electronic throttle valve 8016.

Engine speed sensor 8020 detects the revolution number of an output shaft (the crankshaft) of engine 1000 (hereinafter, also referred to as engine revolution number NE) and transmits a signal representing a detection result to ECU 8000. Input shaft speed sensor 8022 detects the input shaft revolution number NI of automatic transmission 2000 (the turbine revolution number NT of torque converter 2100) and transmits a signal representing a detection result to ECU 8000. Output shaft speed sensor 8024 detects the output shaft revolution number NO of automatic transmission 2000 and transmits a signal representing a detection result to ECU 8000. Oil temperature sensor 8026 detects a temperature (an oil temperature) of oil used for actuating and lubricating automatic transmission 2000 (ATF: Automatic Transmission Fluid) and transmits a signal representing a detection result to ECU 8000. Water temperature sensor 8028 detects a temperature of coolant of engine 1000 (a water temperature) and transmits a signal representing a detection result to ECU 8000.

ECU 8000 controls devices so that the vehicle is in a desired travelling state based on the signals transmitted from position switch 8006, accelerator pedal position sensor 8010, air flow meter 8012, throttle opening position sensor 8018, engine speed sensor 8020, input shaft speed sensor 8022, output shaft speed sensor 8024, oil temperature sensor 8026, water temperature sensor 8028, and the like, a map and a program stored in a ROM (Read Only Memory) 8002. It should be noted that the program to be executed by ECU 8000 may be stored in a recording medium such as a CD (Compact Disc) and a DVD (Digital Versatile Disc) and distributed on the market.

ECU 8000 may be divided into a plurality of ECUs.

In the present embodiment, ECU 8000 controls automatic transmission 2000 so that any of first to eighth forward gears is implemented in the case where a D (drive) range is selected as a shift range of automatic transmission 2000 by placing shift lever 8004 at a D (drive) position. Since friction engagement elements (a clutch and a brake) described later are engaged in a predetermined combination so as to couple an input shaft and an output shaft of automatic transmission 2000, the gear is implemented. When any gear among the first to eighth forward gears is implemented, the torque can be transmitted to rear wheels 7000. It should be noted that a gear of a higher speed than the eighth gear may be implemented in the D range. A gear to be implemented is determined based on a shift map preliminarily prepared by an experiment or the like taking the vehicle speed and the accelerator pedal position as parameters.

By placing shift lever 8004 at an N (neutral) position or a P (parking) position, in the case where an N (neutral) range or a P (parking) range is selected as the shift range of automatic transmission 2000, the friction engagement elements are disengaged, and automatic transmission 2000 is in a neutral state. In the neutral state, the input shaft and the output shaft of automatic transmission 2000 are shut off.

With reference to Fig. 2, planetary gear unit 3000 will be described. Planetary gear unit 3000 is connected to torque converter 2100 having an input shaft 2102 coupled to the crankshaft.

Planetary gear unit 3000 includes a front planetary 3100, a rear planetary 3200, a Cl clutch 3301, a C2 clutch 3302, a C3 clutch 3303, a C4 clutch 3304, a Bl brake 331 1, a B2 brake 3312, and a one-way clutch (F) 3320.

Front planetary 3100 is a planetary gear mechanism of a double pinion type. Front planetary 3100 includes a first sun gear (Sl) 3102, a pair of first pinion gears (Pl) 3104, a carrier (CA) 3106, and a ring gear (R) 3108.

First pinion gears (Pl) 3104 are meshed with first sun gear (Sl) 3102 and first ring gear (R) 3108. First carrier (CA) 3106 supports first pinion gears (Pl) 3104 so

that first pinion gears (Pl) 3104 can be rotated around an outer axis and also around their own axes.

First sun gear (Sl) 3102 is fixed to a gear case 3400 so as not to rotate. First carrier (CA) 3106 is coupled to an input shaft 3002 of planetary gear unit 3000. Rear planetary 3200 is a Ravigneaux type planetary gear mechanism. Rear planetary 3200 includes a second sun gear (S2) 3202, a second pinion gear (P2) 3204, a rear carrier (RCA) 3206, a rear ring gear (RR) 3208, a third sun gear (S3) 3210, and a third pinion gear (P3) 3212.

Second pinion gear (P2) 3204 is meshed with second sun gear (S2) 3202, rear ring gear (RR) 3208, and third pinion gear (P3) 3212. Third pinion gear (P3) 3212 is meshed with third sun gear (S3) 3210 in addition to second pinion gear (P2) 3204.

Rear carrier (RCA) 3206 supports second pinion gear (P2) 3204 and third pinion gear (P3) 3212 so that second pinion gear (P2) 3204 and third pinion gear (P3) 3212 can be rotated around an outer axis and also around their own axes. Rear carrier (RCA) 3206 is coupled to one-way clutch (F) 3320. Rear carrier (RCA) 3206 cannot be rotated when driving in the first gear (when the vehicle travels by using drive force outputted from engine 1000). Rear ring gear (RR) 3208 is coupled to an output shaft 3004 of planetary gear unit 3000.

One-way clutch (F) 3320 is provided in parallel to B2 brake 3312. That is, an outer race of one-way clutch (F) 3320 is fixed to gear case 3400, and an inner race is coupled to rear carrier (RCA) 3206.

Fig. 3 shows a working table illustrating a relationship between the shift gears and working states of the clutches and the brakes. First to eighth forward gears and first and second reverse gears are implemented by actuating the brakes and the clutches in combinations shown in this working table.

With reference to Fig. 4, a principal portion of oil hydraulic circuit 4000 will be described. It should be noted that oil hydraulic circuit 4000 is not limited to the one described below.

Oil hydraulic circuit 4000 includes an oil pump 4004, a primary regulator valve

4006, a manual valve 4100, a solenoid modulator valve 4200, an SLl linear solenoid

(hereinafter, indicated as SL (I)) 4210, an SL2 linear solenoid (hereinafter, indicated as

SL (2)) 4220, an SL3 linear solenoid (hereinafter, indicated as SL (3)) 4230, an SL4 linear solenoid (hereinafter, indicated as SL (4)) 4240, an SL5 linear solenoid

(hereinafter, indicated as SL (5)) 4250, an SLT linear solenoid (hereinafter, indicated as

SLT) 4300, and a B2 control valve 4500.

Oil pump 4004 is coupled to the crankshaft of engine 1000. Oil pump 4004 is driven by rotation of the crankshaft so as to generate oil pressure. The oil pressure generated in oil pump 4004 is regulated by primary regulator valve 4006 so as to generate line pressure.

Primary regulator valve 4006 is actuated taking throttle pressure regulated by

SLT 4300 as pilot pressure. The line pressure is supplied to manual valve 4100 through a line pressure oil channel 4010. Manual valve 4100 includes a drain port 4105. The oil pressure of a D range pressure oil channel 4102 and an R range pressure oil channel 4104 is discharged from drain port 4105. In the case where a spool of manual valve 4100 is at a D position, line pressure oil channel 4010 communicates with D range pressure oil channel 4102.

Therefore, the oil pressure is supplied to D range pressure oil channel 4102. At this point, R range pressure oil channel 4104 communicates with drain port 4105.

Therefore, R range pressure of R range pressure oil channel 4104 is discharged from drain port 4105.

In the case where the spool of manual valve 4100 is at an R position, line pressure oil channel 4010 communicates with R range pressure oil channel 4104. Therefore, the oil pressure is supplied to R range pressure oil channel 4104. At this point, D range pressure oil channel 4102 communicates with drain port 4105.

Therefore, D range pressure of D range pressure oil channel 4102 is discharged from drain port 4105.

In the case where the spool of manual valve 4100 is at an N position or a P position, both D range pressure oil channel 4102 and R range pressure oil channel 4104 communicate with drain port 4105. Therefore, the D range pressure of D range pressure oil channel 4102 and the R range pressure of R range pressure oil channel 4104 are discharged from drain port 4105.

The oil pressure supplied to D range pressure oil channel 4102 is eventually supplied to Cl clutch 3301, C2 clutch 3302, and C3 clutch 3303. The oil pressure supplied to R range pressure oil channel 4104 is eventually supplied to B2 brake 3312.

Solenoid modulator valve 4200 regulates the oil pressure to be supplied to SLT 4300 (solenoid modulator pressure) to a constant level taking the line pressure as source pressure.

SL ( 1 ) 4210 regulates the oil pressure supplied to C 1 clutch 3301. SL (2) 4220 regulates the oil pressure supplied to C2 clutch 3302. SL (3) 4230 regulates the oil pressure supplied to C3 clutch 3303. SL (4) 4240 regulates the oil pressure supplied to C4 clutch 3304. SL (5) 4250 regulates the oil pressure supplied to B 1 brake 3311.

SLT 4300 regulates the solenoid modulator pressure in accordance with a control signal from ECU 8000 based on the accelerator pedal position detected by accelerator pedal position sensor 8010 so as to generate the throttle pressure. The throttle pressure is supplied to primary regulator valve 4006 through an SLT oil channel 4302. The throttle pressure is used as the pilot pressure of primary regulator valve 4006.

SL (1) 4210, SL (2) 4220, SL (3) 4230, SL (4) 4240, SL (5) 4250, and SLT 4300 are controlled by the control signal sent from ECU 8000.

B2 control valve 4500 selectively supplies the oil pressure from one of D range pressure oil channel 4102 and R range pressure oil channel 4104 to B2 brake 3312. D range pressure oil channel 4102 and R range pressure oil channel 4104 are connected to B2 control valve 4500. B2 control valve 4500 is controlled by the oil pressure supplied from an SLU solenoid valve (not shown) and the urge of a spring.

In the case where the SLU solenoid valve is ON, B2 control valve 4500 attains the left side state of Fig. 4. In this case, B 2 brake 3312 is supplied with oil pressure obtained by regulating the D range pressure taking the oil pressure supplied from the SLU solenoid valve as the pilot pressure. In the case where the SLU solenoid valve is OFF, B2 control valve 4500 attains the right side state of Fig. 4. In this case, B2 brake 3312 is supplied with the R range pressure.

With reference to Fig. 5, ECU 8000 serving as a control apparatus according to the present embodiment will be further described. "F" indicates the drive force, "TE" indicates engine torque and "N" indicates the revolution number in Fig. 5. It should be noted that functions of ECU 8000 described below may be implemented by either hardware or software.

As shown in Fig. 5, ECU 8000 is mounted with an engine controller 9000, a power train manager (PTM) 9100, an ECT (Electronic Controlled Transmission) part 9200, a power train driver model (PDRM) 9300.

Engine controller 9000 controls the devices provided in engine 1000 for controlling the output torque (the engine torque) of engine 1000 such as electronic throttle valve 8016, spark, and an EGR (Exhaust Gas Recirculation) valve in order to realize target engine torque inputted from power train manager 9100. Power train manager 9100 sets the target engine torque of engine 1000 based on the operations of the driver, an action of the vehicle, a demand from ECT part 9200, or the like. More specifically, in a setter 9102, smaller target engine torque of first target engine torque set in consideration of target drive force of the vehicle and second target engine torque set in consideration of the target engine revolution number NET is set as final target engine torque to be outputted to engine controller 9000. It should be noted that larger target engine torque may be set as the final target engine torque.

Power train manager 9100 accommodates target drive force set by power train driver model 9300 and target drive force set through VDIM (Vehicle Dynamics

Integrated Management), damping control, maximum vehicle speed restricting control or the like in a drive force accommodator 9110 in order to set the first target engine torque in consideration of the target drive force of the vehicle. For example, the minimum target drive force or the maximum target drive force is selected in drive force accommodator 9110.

The VDIM is a system for integrating VSC (Vehicle Stability Control), TRC (TRaction Control), ABS (Anti lock Brake System), EPS (Electric Power Steering), and the like. The VDEvI calculates a difference between a traveling image of the driver with regard to control input for an accelerator, steering and the brake and a vehicle action with regard to various sensor information, and controls the drive force of the vehicle, braking oil pressure, or the like so as to reduce the difference.

The VSC is control of automatically setting the braking oil pressure of wheels, the target drive force of the vehicle, or the like so as to ensure stability of the vehicle in the case where a sensor detects a state in which front and rear wheels are likely to skid. The TRC is control of automatically setting the braking oil pressure of the wheels, the target drive force of the vehicle, or the like so as to ensure optimal drive force when a sensor senses idling of drive wheels at the time of starting and accelerating the vehicle on a slippery road surface.

The ABS is a control system of automatically setting an optimal value of the braking oil pressure so as to prevent locking of the wheels. The EPS is a control system of assisting an operation of a steering wheel by force of an electric motor.

The damping control is control of setting target drive force for reducing pitting and bouncing of the vehicle calculated using a vehicle model from actual drive force of the vehicle or the like. A generally known technique may be used for a method of setting the drive force for reducing the pitting and the bouncing of the vehicle. Therefore, a further detailed description will not be repeated here.

The maximum vehicle speed restricting control is control of setting target drive force for restricting the vehicle speed to be predetermined maximum vehicle speed or

lower in accordance with a current acceleration and a vehicle speed for example.

The target drive force accommodated in drive force accommodator 9110 is converted into the target engine torque in a torque converting part 9112. For example, the drive force is converted into the torque using a radius of rear wheels 7000, a gear ratio of differential gear 6000, a current gear ratio of automatic transmission 2000, a torque ratio of torque converter 2100, or the like. It should be noted that a generally well-known technique may be used for a method of converting the drive force into the torque. Therefore, a further detailed description will not be repeated here.

One of the target engine torque converted from the target drive force and the target engine torque set by ECT part 9200 is set as the first target engine torque in a torque accommodator 9114. The engine torque to be set as the first target engine torque is determined in accordance with an operation state of the vehicle, a shift state of automatic transmission 2000, or the like.

Power train manager 9100 accommodates target engine revolution number NET set by power train driver model 9300 and target engine revolution number NET set by ECT part 9200 in a revolution number accommodator 9120 in order to set the second target engine torque in consideration of target engine revolution number NET. The target engine torque to be selected is determined in accordance with the operation state of the vehicle or the like. Target engine revolution number NET accommodated in revolution number accommodator 9120 is inputted to a controller 9130.

Controller 9130 converts target engine revolution number NET into the second target engine torque. In the present embodiment, controller 9130 sets the second target engine torque suitable for a state in which the input shaft and the output shaft of automatic transmission 2000 are shut off, that is, the neutral state. This is due to the fact that a function of controller 9130 is to control engine 1000 based on target engine revolution number NET particularly in the neutral state of automatic transmission 2000.

With reference to Fig. 6, a method of converting target engine revolution number NET into the target engine torque by controller 9130 will be described.

Controller 9130 includes a feed forward controller 9132 and a feedback controller 9134.

Feed forward controller 9132 converts target engine revolution number NET into the second target engine torque by adding engine torque required for changing engine revolution number NE to target engine revolution number NET to engine torque required for maintaining engine revolution number NE.

In the present embodiment, the sum of engine torque lost due to friction resistance of engine 1000 itself and a load of oil pump 4004 and engine torque required for maintaining the revolution number of an input shaft of torque converter 2100 is calculated as the engine torque required for maintaining engine revolution number NE. It should be noted that the engine torque required for maintaining engine revolution number NE is not limited thereto.

The engine torque lost due to the friction resistance of engine 1000 itself and the load of oil pump 4004 has engine revolution number NE as a parameter and is calculated, for example, according to a map preliminarily made by an experiment or the like. The engine torque required for maintaining the revolution number of the input shaft of torque converter 2100 is calculated using, for example, torque capacity τ (the engine torque required for maintaining the revolution number of the input shaft/the engine revolution number NE ² ) determined by a speed ratio e (turbine revolution number NT/engine revolution number NE) of torque converter 2100 and engine revolution number NE. Torque capacity τ is also called as capacity coefficient.

The engine torque required for changing engine revolution number NE to target engine revolution number NET is calculated using inertia and a change rate of target engine revolution number NET (an angular acceleration). The product of the inertia and the change rate of target engine revolution number NET is calculated as the engine torque required for. changing engine revolution number NE.

Inertia from engine 1000 to the input shaft of automatic transmission 2000 is used as the above inertia. More specifically, the inertia is inertia of a member positioned on the side of engine 1000 relative to a forward clutch (particularly Cl clutch

3301) over a torque transmission route among engine 1000, a drive plate, torque converter 2100, and automatic transmission 2000. That is, the inertia in the case where automatic transmission 2000 is in the neutral state (the state in which the input shaft and the output shaft are shut off) is used. The inertia is preliminarily stored as data. Feedback controller 9134 executes feedback control using target engine revolution number NET and actual engine revolution number NE and corrects the second target engine torque. More specifically, PID (Proportion Integration Differential) control is executed with regard to a difference between target engine revolution number NET and actual engine revolution number NE, and a correction amount of the engine torque is calculated so as to reduce the difference between target engine revolution number NET and actual engine revolution number NE. The calculated correction amount is restricted so as to be a predetermined lower limit value or more and a predetermined upper limit value or less.

The feedback control is executed only in the case where the second target engine torque converted from target engine revolution number NET is set (selected) as the final target engine torque. An initial value of the correction amount of the torque when the feedback control is started is, for example, zero.

In the case where the difference between target engine revolution number NET and actual engine revolution number NE is a threshold value or more, an integrator of the PID control is not actuated. That is, only proportional control and derivative control are performed. This is due to the fact that in the case where the difference between target engine revolution number NET and actual engine revolution number NE is the threshold value or more, automatic transmission 2000 is highly possibly not in the neutral state, in other words, not in a state in which engine 1000 is to be controlled based on target engine revolution number NET.

As mentioned above, controller 9130 calculates the second target engine torque suitable for the case where automatic transmission 2000 is in the neutral state. Therefore, the second target engine torque calculated by controller 9130 is favorable for

the time when automatic transmission 2000 is in the neutral state, performs shifting, executes neutral control, or the like.

Meanwhile, the second target engine torque calculated by controller 9130 is improper for the time when the input shaft and the output shaft of automatic transmission 2000 are coupled to each other through the clutch or the brake and the torque can be transmitted to rear wheels 7000.

However, when the first target engine torque set in consideration of the target drive force of the vehicle is smaller than the second target engine torque calculated by controller 9130, the first target engine torque is set as the final target engine torque. Therefore, control of engine 1000 is not disordered.

Even in the case where the second target engine torque is set as the final target engine torque, smaller target engine torque is set. Therefore, the actual engine torque does not become excessive.

Even in the case where the shift range is erroneously recognized as the neutral range in spite of the fact that the shift range is actually the drive range, the engine torque (the drive force) does not become excessive.

Returning to Fig. 5, ECT part 9200 performs shifting control of automatic transmission 2000 and sets the target engine torque of engine 1000 and target engine revolution number NET demanded for controlling a state of automatic transmission 2000.

The target engine torque set by ECT part 9200 is set so as to realize torque- down or torque-up, for example, for reducing shift shock. ECT part 9200 sets target engine revolution number NET depending on the fact that the input shaft and the output shaft of automatic transmission 2000 are shut off or coupled to each other. ECT part 9200 determines the state of the input shaft and the output shaft of automatic transmission 2000 while distinguishing a control state and an actual state as shown in tables of Figs. 7 and 8. As shown in Figs. 7 and 8, ECT part 9200 determines whether the input shaft and the output shaft of automatic transmission 2000 are shut off

or coupled to each other based on input shaft revolution number NI, output shaft revolution number NO, and the shift range of automatic transmission 2000.

ECT part 9200 sets target engine revolution number NET depending on the control state and the actual state of the input shaft and the output shaft of automatic transmission 2000 as shown in a table of Fig. 9.

It should be noted that an invalid value in Fig. 9 indicates a value determined so that one of the first target engine torque and the second target engine torque is always larger than the other. Therefore, in the case where the invalid value is set as the target drive force, the first target engine torque is larger than the second target engine torque. Similarly, in the case where the invalid value is set as target engine revolution number NET, the second target engine torque is larger than the first target engine torque.

As shown in Fig. 9, in the case where the control is performed so that the input shaft and the output shaft of automatic transmission 2000 are coupled to each other (the control is performed so as to implement any of the gears) and the input shaft and the output shaft are actually coupled to each other, the invalid value is set as target engine revolution number NET.

In the case where the control is performed so that the input shaft and the output shaft of automatic transmission 2000 are coupled to each other and the input shaft and the output shaft are actually shut off, a value determined so as to be preferable for the case where the input shaft and the output shaft of automatic transmission 2000 are actually coupled to each other is set as the target engine revolution number. Target engine revolution number NET at this time is on the premise that the input shaft and the output shaft of automatic transmission 2000 are coupled to each other. Therefore, the value is a value such that actual engine revolution number NE does not become excessive.

Accordingly, when the input shaft and the output shaft are actually coupled to each other, the first target engine torque is set as the final target engine torque, and it is possible to perform the control favorable for the state in which the input shaft and the

output shaft are actually coupled to each other. In the case where the input shaft and the output shaft are actually shut off against the control, the second target engine torque is set as the final target engine torque, and it is possible to control engine 1000 so that actual engine revolution number NE does not become excessive. As shown in Fig. 9, in the case where the control is performed so that the input shaft and the output shaft of automatic transmission 2000 are shut off, a value determined so as to be favorable for the case where the input shaft and the output shaft of automatic transmission 2000 are actually shut off is set as the target engine revolution number. It should be noted that although a value not favorable for the case where the input shaft and the output shaft of automatic transmission 2000 are actually coupled to each other is set as the target engine revolution number, the correction amount of the target engine torque is limited in feedback controller 9134 of controller 9130. Therefore, the control does not fail. In addition, in the case where it is not in the operation state to set the target engine torque or the target engine revolution number, ECT part 9200 sets the invalid value as the target engine torque or the target engine revolution number Therefore, ECT part 9200 always sets and outputs the target engine torque or the target engine revolution number. Returning to Fig. 5, power train driver model 9300 is a model (function) used for setting the target drive force of the vehicle and target engine revolution number NET based on the operations of the driver.

In the present embodiment, as shown in Fig. 10, the target drive force is set from the accelerator pedal position according to the predetermined map based on results of an experiment and simulation or the like. Further, target engine revolution number NET is set based on the accelerator pedal position.

As shown in Fig. 11, target engine revolution number NET is obtained by setting the engine revolution number NEL to be finally reached in accordance with the

accelerator pedal position and processing set engine revolution number NEL in consideration of a delay due to inertia using, for example, a model G (s) represented by a primary delay function. It should be noted that a model represented by a secondary delay function may be used. In model G (s), a calculation using the following equation 1 is executed.

Current NET = previous NET + (current NEL - previous NET)/coefficient (1)

Actual engine revolution number NE at the time of starting the control is used as an initial value of target engine revolution number NET.

Accordingly, as shown in Fig. 12, target engine revolution number NET gradually changing in accordance with the accelerator pedal position is obtained from engine revolution number NE at the time of starting the control.

In order to prevent interference with ISC (Idle Speed Control), the invalid value is set as target engine revolution number NET at the time of idling engine 1000. Other than the time of idling, target engine revolution number NET is set so as not to be lower than the target idling revolution number at the time of executing the ISC.

Further, in a state where the input shaft and the output shaft of automatic transmission 2000 are coupled to each other, more specifically in a state where the driver recognizes that the input shaft and the output shaft are coupled to each other, the target drive force is set in accordance with the accelerator pedal position and the invalid value is set as target engine revolution number NET. Therefore, during the neutral control, during the shifting, and in a state where turbine revolution number NT is excessive, the input shaft and the output shaft are not actually coupled to each other. However, the target drive force is set in accordance with the accelerator pedal position and the invalid value is set as target engine revolution number NET. In a state where the input shaft and the output shaft of automatic transmission

2000 are shut off, more specifically, in a state where the driver recognizes that the input shaft and the output shaft are shut off, the invalid value is set as the target drive force, and target engine revolution number NET is set in accordance with the accelerator pedal

position.

For example, in the case where the neutral range or the parking range is not selected as the shift range (in the case where a traveling range such as the drive range is selected), it is determined that the input shaft and the output shaft of automatic transmission 2000 are coupled to each other (the driver recognizes that the input shaft and the output shaft of automatic transmission 2000 are coupled to each other).

In the case where the neutral range or the parking range is selected as the shift range, it is determined that the input shaft and the output shaft of automatic transmission 2000 are shut off (the driver recognizes that the input shaft and the output shaft are shut off).

It may be determined whether the input shaft and the output shaft of automatic transmission 2000 are shut off or coupled to each other based on input shaft revolution number NI and output shaft revolution number NO of automatic transmission 2000. In addition, power train driver model 9300 sets the invalid value as the target drive force or the target engine revolution number in the case where it is not in the operation state to set the target drive force or the target engine revolution number. Therefore, power train driver model 9300 always sets and outputs the target drive force or the target engine revolution number.

As mentioned above, according to the control apparatus of the present embodiment, one of the first target engine torque set from the target drive force of the vehicle and the second target engine torque converted from the target engine revolution number is set as the final target engine torque used for controlling the engine Accordingly, in the case where the engine is preferably controlled so as to satisfy a demand on the output torque of the engine, that is, a demand on the drive force of the vehicle, the engine can be controlled based on the output torque. In the case where the engine is preferably controlled so as to satisfy a demand on the engine revolution number, the engine can be controlled based on the engine revolution number. As a result, it is possible to improve control accuracy of the engine.

It should be noted that the target turbine revolution number and target turbine torque may be set instead of the target engine revolution number and the target engine torque. That is, it can be regarded that a drive source is configured by the engine and the torque converter. Engine 1000 may be controlled without converting the drive force into the torque.

It is clearly understood that the embodiments shown here are by way of illustration and example in all respects and are not to be taken by way of limitation. The scope of the present invention is interpreted by the terms of the appended claims and not by the above description, and all changes and modifications are to be encompassed without departing from the equivalent meaning and scope of the appended claims.