Abstract: The invention relates to a process of ending a clutch protection function against overload of an automated clutch. The clutch protection function is ended when, by actuating the gas- and brake pedals, an absolute value of a brake pedal signal falls below a default threshold value and the time derivative of the brake pedal signal is negative.

Abstract: A twin clutch controlling apparatus including a shift motor for carrying out a smooth changeover of a shift stage of a multi-speed transmission having a plurality of gear trains between a main shaft and a countershaft, a twin clutch configured from an odd number stage side clutch and an even number stage side clutch, a clutch actuator for controlling the twin clutch, and a manual operation clutch capacity arithmetic operation section for arithmetically operating, based on an operational amount of a clutch lever, a manual operation clutch capacity arithmetic operation value (tqc1tmt) corresponding to the manual operation. The twin clutch controlling apparatus further includes a manual operation clutch decision section for determining with a clutch capacity of which one of the odd number stage side clutch or the even number stage side clutch the manual operation clutch capacity arithmetic operation value (tqc1tmt) is to be interlocked.

Abstract: A twin clutch controlling apparatus wherein a clutch lever is operated during a deceleration operation in which an auto mode (Auto) is selected, then a shift down action from a gear position “N-2” at which a driving force can be transmitted only by one of an odd number stage side clutch CL1 and an even number stage side clutch CL2 to another position “1-2” at which the transmission gear for transmitting a driving force is switched in response to switching control of the clutch is carried out in response to the operation of the clutch lever. After the shift down action, if re-connection of the clutch is to be carried out by the clutch lever, then the clutch (CL1, CL2) on the side to be driven in response to a manual operation clutch capacity arithmetic operation value (tqcltmt) is determined in response to a vehicle speed V.

Abstract: A twin clutch controlling apparatus wherein an interposition of a manual operation into an automatic control clutch can be executed smoothly. The twin clutch controlling apparatus includes an AMT controlling unit for controlling a shift actuator and a clutch actuator, and a shift pedal P for carrying out a shifting request to the AMT controlling unit. If, after driving of the shift actuator is started in response to the shifting request by the shift pedal, a clutch lever is operated in a connection direction before a next stage gear is placed into an in-gear state, then the controlling section drives one of an odd number stage side clutch and an even number stage side clutch which corresponds to the gear before the shifting in a corresponding relationship to a manual operation clutch capacity arithmetic operation value.

Abstract: In a method for engaging a clutch having at least one previously known touch point position, the clutch is engaged according to a speed profile, the course of which depends on at least one of the previously known touch point positions.

Abstract: A control device for controlling an engagement state of a lock-up clutch is provided. A plurality of target slip ratio maps include a normal slip ratio map having a characteristic line of a target slip ratio defined in accordance with an engine load at a normal vehicle running condition and a modified slip ratio map having a characteristic line of the target slip ratio to become a facing calorific value lower than a facing calorific value corresponding to the slip ratio retrieved from the normal slip ratio map. In the case where an estimate value of the facing temperature continues to exceed first threshold temperature for more than predetermined time when to carry out slip control using the normal slip ratio map, control to switch the target slip ratio map from the normal slip ratio map to the modified slip ratio map is carried out.

Abstract: Apparatus (control device) and a method for controlling a torque transmitting device such as a brake, wet clutch, dry clutch (10) during a filling and slip phase is provided, e.g. for coupling a first shaft (12) to a second shaft (14) via the wet clutch (10). A reference profile (52) for a control variable is provided, wherein the chronological progress of said control variable influences the position of a piston (22) for actuating clutch elements (16, 18). Each clutch element (16, 18) is connected to the first shaft (12) or the second shaft (14), with respect to a cylinder (20) of the wet clutch (10), and the control variable is determined during each coupling and a valve (38) for applying a pressure source to the piston (22) is operated, wherein the valve (38) is controlled during each coupling by means of a feed forward closed loop control (54) such that the control variable follows the reference profile (52).

Abstract: A clutch control device for controlling a clutch installed between an engine and a transmission in a power transmission device for a vehicle includes a clutch actuator driven by a working fluid, a stroke sensor for detecting a movement of the clutch actuator, a flow rate control valve for controlling an amount of the working fluid in the clutch actuator, and a flow rate control valve control device for controlling a position of a valve body of the flow rate control valve responsive to a detection signal from the stroke sensor.

Abstract: A twin-clutch type hybrid transmission is configured to include an input shaft 10, an odd-numbered stage shift mechanism 30, an even-numbered stage shift mechanism 60, a motor power mechanism 20, and an output mechanism 90. The shift mechanisms 30 and 60 include transmission gear trains 32 and 62, and main clutches 34 and 64, respectively, the main clutches 34 and 64 for selectively transmitting the power of the transmission gear train 32 and the power of the transmission gear train 62 to transmission shafts 40 and 70, respectively. The shift mechanisms 30 and 60 also include shift gear trains 41, 43, 45, 47, 72, 74, 76, and 78 provided to the transmission shafts 40 and 70 to transmit rotation to the output mechanism 90, respectively, and mechanical clutches 50, 52, 80, and 82 for selectively engaging the corresponding shift gear trains and the transmission shafts 40 and 70, respectively. As a result, a compact twin-clutch type hybrid transmission having high transmission efficiency can be obtained.

Abstract: A clutch control device that controls a clutch by driving a piston using a working fluid, having: stroke start determining means (S1) for determining that a stroke of the piston has started and detecting a stroke start oil pressure at that time; stroke end determining means (S4) for determining that the stroke of the piston is complete and detecting a stroke end oil pressure at that time; stroke end range estimating means (S3) for estimating a range of the stroke end oil pressure from the stroke start oil pressure detected by the stroke start determining means; and learning means (S5, S6) for learning the stroke end oil pressure detected by the stroke end determining means when the stroke end oil pressure is within the estimated range of the stroke end oil pressure. Learning precision of the stroke end oil pressure can be improved.

Abstract: The present invention relates to a method for actuating the stop & start function in a moving vehicle, especially an industrial or commercial or special vehicle, said vehicle being equipped with hybrid drive of the parallel type, comprising a thermal engine (1), an electric motor-generator (2), a single clutch unit (3) placed between the two engines, a transmission system (6) comprising an automated manual transmission, a hybrid power steering both hydraulic and electric, the method comprising the steps of enabling of the stop phase, activation of the stop phase, maintaining of the stop phase, activation of the start phase.

Abstract: The invention relates to a control device and to a method for controlling an automated clutch, which includes a hydraulic clutch actuating system, which has a hydrostatic actuator, which is driven by and electric-motor actuating drive having an incremental displacement sensor in such a way that the actuator moves in a translatable manner. The invention includes an absolute displacement sensor, which detects the actuator position.

Abstract: In an idle stop system for an engine mounted in a vehicle, when it is determined predetermined stop conditions are met, the engine is automatically stopped. During the engine stop, when it is determined that predetermined restart conditions are met, the engine is automatically restarted. Further, it is determined whether or not a predetermined period of time has elapsed since the restart of the engine. When it is determined that the predetermined period of time has elapsed, the clutch mechanism is controlled into the connection thereof at and after a time instant when it is determined that the predetermined period of time has elapsed. Hence, the connected state of the clutch mechanism is realized after a controlled delay.

Abstract: A clutch unit (47) comprises a wet friction clutch for controllable transmission of a torque from an input element (41) to an output element (45), housing that contains the friction clutch and oil for cooling the friction clutch, and an actuator (51) for actuating the friction clutch. The actuator is attached to the housing in a thermally conductive way and has a temperature sensor (108) for sensing a temperature of the actuator. In order to computationally determine the oil temperature (TÖl) in the clutch unit (47), a thermal input power to the clutch unit is determined as a function of at least a speed of the input element and/or of the output element. The difference between the thermal input power and the thermal output power is determined, and the oil temperature is determined as a function of the difference that was determined.

Abstract: A hybrid powertrain includes a plurality of torque generative devices, a transmission input shaft, and a planetary gear set connecting the torque generative devices to the transmission input shaft. A method to control the powertrain includes monitoring a desired configuration of the powertrain and selectively grounding a gear of the planetary gear set with a selectable one way clutch based upon the desired configuration of the powertrain.

Abstract: A control apparatus and a control method for a vehicular drive apparatus that includes a driving power source, and a power transmission device that transmits power from the driving power source to a drive wheel are provided. It is determined that a malfunction occurs in the power transmission device, when a comparison value remains equal to or above a predetermined value for a predetermined period. The comparison value is obtained by making a comparison between an actual value and a theoretical value that relate to a rotational speed of a predetermined rotational member that constitutes at least a part of the vehicular drive apparatus. The predetermined period is set according to an operating state of the power transmission device. Thus, it is possible to reduce the possibility that it is erroneously determined that a malfunction occurs, and to quickly determine that a malfunction occurs.

Abstract: A vehicle includes a cruise control section arranged and programmed to perform control to maintain the vehicle speed at a prescribed vehicle speed while a clutch is engaged. A clutch actuator control section performs control to disengage the clutch when the value of a parameter becomes equal to or lower than a first threshold value, in the case where the cruise control section is determined to not be performing the control to maintain the vehicle speed at a prescribed vehicle speed; and performs the control to disengage the clutch when the value of the parameter becomes equal to or lower than a second threshold value, which is lower than the first threshold value, in the case where the cruise control section is determined to be performing the control to maintain the vehicle speed at a prescribed vehicle speed.

Abstract: A method for controlling a clutch unit for a drive train of a motor vehicle wherein the temperature in the friction clutch is ascertained and a characteristic curve of the friction clutch is adapted as a function of the ascertained temperature.

Abstract: A method of detecting synchronizer misalignment in a vehicle transmission, includes: applying an engagement force to an input side of a synchronizer or output side of the synchronizer; monitoring a performance characteristic of a power source configured to apply the engagement force; and determining a misalignment based on the performance characteristic exceeding or not achieving a predetermined threshold.

Abstract: A control device of a vehicle drive device in which an output of a power source is input from a hydraulic power transmission device via a friction engagement device to a continuously variable transmission and transmitted toward drive wheels after speed is changed by the continuously variable transmission, the control device includes: an abnormality detecting portion configured to make a determination of abnormality indicating that the friction engagement device is in a complete release state or a slip state; and an abnormality distinguishing portion, if the abnormality detecting portion makes a determination of abnormality, configured to judge that the friction engagement device is in the slip state when an input/output rotation speed difference between an input rotation speed and an output rotation speed of the hydraulic power transmission device is equal to or greater than a predetermined slip determination value and that the friction engagement device is in the complete release state when the input/output

Abstract: A machine is described that includes an engine, a multi-clutch transmission and a controller. The controller is configured with computer-executable instructions for managing operation of the multi-clutch transmission to avoid autoengagement of a disengaged clutch. The computer-executable instructions configure the controller to receive sensor signals indicative of current operating status of the machine; determine, based upon the sensor signals, a configured minimum engine speed needed to avoid autoengagement of the disengaged clutch; and conditionally increase an engine speed based upon a comparison of the configured minimum engine speed and a sensed current engine speed.

Abstract: A vehicle control method for a vehicle having an internal combustion engine coupled to a torque converter is described. In one embodiment, the engine air flow and spark are adjusted to control torque converter operation. The method can improve vehicle response to driver accelerator commands.

Abstract: A system and method for determining a required throttle position and operating a throttle in the required throttle position to attain a required engine speed for fuel cut acquisition is disclosed. A lock-up clutch may be engaged without a shock if a required engine speed is achieved that corresponds to a current transmission speed. Fuel economy may be increased by cutting fuel to the engine when a lock-up clutch is engaged.

Abstract: A vehicle includes an engine, an automatic transmission, and a controller. The transmission includes a neutral idle (NI) state and a designated NI clutch which is selectively actuated to exit the NI state. The controller executes instructions from tangible memory to shift out of the NI state and into a drive state. The controller includes a slip model which generates a desired clutch slip profile as a differentiable time function, and a desired slip derivative of the desired slip profile. The desired profiles are used to calculate a clutch pressure command for controlling the designated NI clutch. The time function may be at least a third order/cubic equation. A method includes executing the slip model to generate the desired clutch slip profile, calculating a desired slip derivative of the desired slip profile, and using the desired slip profile derivative to calculate a clutch pressure command for the designated NI clutch.

Abstract: A clutch arrangement for a transmission which comprises a wet separating clutch having a clutch housing, in which a clutch piston separates an interior space from a pressure chamber. The separating clutch is engaged by pressurizing the pressure chamber with an actuating pressure so that the clutch piston moves into an actuation position and, as a result, two clutch halves, located in the interior space and surrounded by fluid, frictionally engage one another. So as to reliably engage the separating clutch without impairing the surrounding components with the fluid, the actuating pressure includes at least one compensation pressure portion that corresponds to the counter pressure depending on the fluid located in the interior space opposing the clutch piston during transfer into the actuation position. A method of controlling a separating clutch, and a computer program product and a data medium incorporating the computer program product are also disclosed.

Abstract: A method is provided for controlling an electromechanical clutch system in a motor vehicle. The motor vehicle includes, but is not limited to a clutch and a clutch pedal uncoupled mechanically from the clutch. The system is configured to determine a gear input rotation speed (nG), determine a pedal travel (w) covered by the clutch pedal, compare a maximum rotation speed (nmax) of the engine with the gear input rotation speed (nG), actuate the clutch independently of the pedal travel (w), when the gear input rotation speed (nG) is greater than the maximum rotation speed (nmax) of the engine, and the pedal travel (w) is so small that an actuation of the clutch (12) dependent on the pedal travel (w) would lead to an exceeding of the maximum rotation speed (nmax).

Abstract: A system is provided for managing torque in a vehicle driveline coupled to an internal combustion engine and to a hybrid motor/generator. An engine control circuit provides to a transmission control circuit an engine torque value corresponding to torque applied by the engine to the driveline. A hybrid control circuit provides to the transmission control circuit a motor torque value corresponding to torque applied by the hybrid motor/generator to the driveline. The transmission control circuit controls operation of at least one friction device and controls shifting of the transmission, and also manages torque applied to the drive line by the engine and by the hybrid motor/generator based on the engine torque value and the motor torque value such that the friction device control and shift schedule instructions do not require modification to accommodate inclusion of the hybrid motor/generator in the system or exclusion of the hybrid motor/generator from the system.

Abstract: An on-demand-type drive state control apparatus for a vehicle is provided. In the case where acceleration slippage occurs at drive wheels (rear wheels) of a vehicle when a drive system is in a two-wheel drive state, the drive system is switched from the two-wheel drive state to a four-wheel drive state. That is, the maximum transmittable torque of a multi-disc clutch mechanism increases from “0” to a predetermined value. In the four-wheel drive state, the maximum transmittable torque decreases stepwise from the present value by a predetermined value every time the vehicle travels over a predetermined distance in a state in which none of the wheels cause acceleration slippages. That is, the clutch drive current supplied to the multi-disc clutch mechanism decreases gradually (stepwise or in a plurality of steps), and the drive torque distributed to the front wheels (rear wheels) decreases (increases) gradually.

Abstract: An apparatus and method of controlling a torque transmitting apparatus having multiple selectively engageable couplers is provided. The multiple couplers may be selectively engaged and disengaged to provide a mechanical, friction or fluid coupling between portions of the torque transmitting apparatus and other components of a vehicle powertrain during various operational stages. The control apparatus includes a fluid pressure control device and a fluid flow control device.

Abstract: A transmission includes an electro-hydraulic controller that includes redundancy in the hydraulic circuit that permits single fault failures to be compensated for by changing the flow path of hydraulic fluid to bypass the single fault failure. The redundancy results in the ability of the transmission to maintain full operation in all modes.

Abstract: An automotive electronic control system for a motor vehicle is provided. The automotive electronic control system is designed to cause the motor vehicle to enter a freewheel running condition with internal combustion engine off if the automotive electronic control system determines, based on received quantities indicative of operative conditions of the motor vehicle, occurrence of a driver-performable action indicative of the will of the driver to enter a freewheel running condition with internal combustion engine off and occurrence at or within a given time from the occurrence of the driver-performable action and the maintaining for a given time of specific predetermined entry conditions. The automotive electronic control system is further designed to cause the motor vehicle to leave a freewheel running condition with internal combustion engine off if the automotive electronic control system determines, based on the received quantities, occurrence of at least one of specific predetermined exit conditions.

Abstract: A vehicle includes a transmission, a motor configured to provide a motor torque to the transmission, and an engine configured to provide an engine torque to the transmission. A torque converter is operably disposed between the transmission and the motor, the engine, or both. The torque converter is configured to at least partially transfer at least one of the motor torque and the engine torque to the transmission in accordance with a plurality of k-factors. The torque converter includes a clutch configured to at least partially engage to change the effective k-factor applied by the torque converter. A control processor is configured to blend the plurality of k-factors and at least partially engage the clutch based on the blended k-factor.

Abstract: An electro-hydraulic clutch system for a motor vehicle includes a clutch mechanism that selectively engages an engine of the motor vehicle with a gear box, an actuator that pumps and retrieves hydraulic fluid to and from the clutch mechanism to activate the clutch mechanism, and a solenoid with a valve and/or a check ball that is disposed in the path of the hydraulic fluid between the actuator and the clutch mechanism. The solenoid has a normally closed position to prevent flow of the hydraulic fluid back to the actuator in the event of a system failure. The solenoid can also be used to reduce energy consumption in steady state conditions.

Abstract: An estimating method for transmitting torque of a dry type clutch in a vehicle, may include a slip determining step of determining by a processor whether only one clutch slips between an engine and a transmission, a transmitting torque estimating step of estimating a current transmitting torque of the dry type clutch by using a torque observer when the only one clutch slips as a result of performing the slip determining step, and an updating step of reflecting the current transmitting torque of the dry type clutch estimated in the transmitting torque estimating step and an actuator torque in the transmitting torque estimating step to a T-S (Torque-Stroke) curve.

Abstract: A method for processing a signal originating from a position sensor of a motor vehicle control member, to produce a processed signal relating to the position of the control member. The method includes: a filtering phase in which the signal originating from the sensor is filtered using a first filter to obtain a first filtered signal, and a substitution phase in which the first filtered signal is supplied as the processed signal, a second signal being added to the first filtered signal if the instantaneous value thereof is greater than the value of a first threshold parameter, and, in the opposite case, the signal originating from the sensor is provided as the processed signal.

Abstract: A control system for a transmission includes a memory module, a position module, an error module, an integral module, and an adjustment module. The memory stores a control value as a function of clutch torque. The position module controls a position of a clutch based on the control value. The error module periodically determines a slip speed error based on a difference between a target slip speed and an estimated slip speed of the clutch. The integral module periodically determines an integral of the slip speed error. The adjustment module adjusts the control value based on the integral. A method for controlling a transmission is also provided.

Abstract: A device, system, and method for controlling transmission torque to provide hill ascent and/or descent assistance to a vehicle includes applying a clutch hold pressure to one or more clutches of a transmission to lock an output shaft of the transmission to resist roll-back of the vehicle. The clutch hold pressure is applied based on one or more of a transmission output speed signal, an engine throttle signal, and a vehicle brake signal.

Abstract: A device, system, and method for controlling transmission torque to provide hill ascent and/or descent assistance to a vehicle includes applying a clutch hold pressure to one or more clutches of a transmission to lock an output shaft of the transmission to resist roll-back of the vehicle. The clutch hold pressure is determined as a function of the tractive effort of the vehicle and is applied based on one or more of a transmission output speed signal, an engine throttle signal, and a vehicle brake signal.

Abstract: First and second clutches correspond to systems which include “first gear” and “second gear,” respectively. When the temperature of the first clutch at the time of start of the vehicle is lower than a first temperature, only the first clutch is used as a start clutch for driving the vehicle. When the temperature of the first clutch is not lower than the first temperature but is lower than a second temperature, both the first and second clutches are used as the start clutch. When the temperature of the first clutch is equal to or higher than the second temperature, only the second clutch is used as the start clutch. Thus, the higher the temperature of the first clutch, the smaller the load acting on the first clutch. When the temperature of the second clutch is high, engine torque is reduced, and a warning is issued.

Abstract: A method for setting the engagement point of a friction clutch of a multi-step transmission for a motor vehicle. The friction clutch can be activated, controlled, by means of a clutch actuator. A set point value of the clutch actuator is set for the engagement point of the friction clutch as a function of a time profile of a physical variable which occurs starting from a transition state after activation of the friction clutch to a transition value. An electric machine is connected to the multi-step transmission. Influencing of the multi-step transmission by the electric machine is taken into account in the setting of the engagement point of the friction clutch.

Abstract: A touch point calibration method for a motor vehicle is disclosed. The method includes steps for determining if the touch point can be calibrated. The method also includes steps for determining the touch point when the system can be calibrated.

Abstract: A method of adapting control of clutches of a double clutch transmission, including: during a shifting process, controlling torque transmittable by an opening clutch and torque transmittable by a closing clutch according to nominal curves; during a shifting process, determining a difference between a nominal value and an actual value; and adapting a nominal curve of at least one of the clutches for a following shifting process by reducing a difference between the nominal value and the actual value.

Abstract: A working fluid medium temperature control system comprises an actuator operable on a working fluid medium, a pump for the working fluid medium, a fluid passage structure for the working fluid medium, an electric motor drivingly connected to the pump, and a control unit for the electric motor, the control unit including an inverter and an inverter controller. The inverter and the electric motor are integrated in such a way that the inverter is in heat transfer communication with the electric motor. The fluid passage structure is in heat transfer communication with the inverter.

Abstract: A method of controlling a drivetrain of a vehicle in which the drivetrain comprises a motor, a transmission with starting gears and a clutch located between the motor and transmission, a manual shift lever, and a control unit, for controlling the transmission and clutch, that communicates with a speed sensor, and an accelerator pedal and shift lever actuation sensors. When starting off from coasting, a starting gear is determined in a manner that can be influenced by the driver via actuating the manual shift lever. To assist the driver, it is checked whether the transmission is in neutral and the clutch is engaged, if the vehicle speed is within a specified speed range. If so, the clutch is disengaged, another gear is engaged, and starting is initiated in combination with situation-dependent clutch engagement and carried out as a function of accelerator pedal actuation, provided the shift lever has not been actuated.

Abstract: A vehicle includes a motor/generator, a starter motor, a disconnect clutch disposed between the engine and the motor/generator, and at least one clutch disposed between the motor/generator and the vehicle drive wheels. When an engine start is requested, various parameters are controlled to ensure a smooth engine start wherein driveline torque disturbances are minimized. The starter motor is used to crank the engine upon an engine start request, thereby eliminating the need to transfer torque from the motor/generator to the engine. This helps to further reduce torque disturbances in the driveline when the engine is started.

Abstract: A vehicle has an engine having a crankshaft, a hydraulically controlled multi-plate clutch operatively connected to the crankshaft, and an output shaft operatively connected to the clutch. The clutch selectively transmits power from the crankshaft to the output shaft. A propulsion element is operatively connected to the output shaft. A hydraulic fluid supply system is fluidly connected to the clutch for supplying pressurized hydraulic fluid to the clutch. A controller is connected to the hydraulic fluid supply system. The controller receives a torque signal indicative of engine torque and controls the hydraulic fluid supply system based at least in part on the torque signal. A clutch control method and system are also disclosed.

Abstract: A method for reducing occurrence of clutch slip in electromechanical transmission adapted to selectively transmit mechanical power to an output member through selective application of a hydraulically actuated clutch includes monitoring operation of said clutch, identifying an indication of clutch wear based upon said monitoring said operation, and increasing a minimum clamping force applied to said clutch based upon said indication of clutch wear.

Abstract: A power transfer mechanism control device that controls a power transfer mechanism which is mounted on a vehicle including an automatically stoppable and automatically startable motor and which transfers power from the motor to an axle side via a friction engagement element actuated by a fluid pressure from a fluid pressure actuator, wherein during neutral control performed while the motor is in operation, a neutral control amount, which is a control amount for causing the friction engagement element to stand by in a neutral state with pressure lower than a complete engagement pressure, is set on the basis of a power transfer state of the power transfer mechanism to control the fluid pressure actuator, and learned, and while the motor is automatically stopped, the fluid pressure actuator is controlled using the learned neutral control amount such that the friction engagement element stands by in the neutral state.

Abstract: A method of actuating a clutch of a hydrodynamic torque converter in a self-propelling working machine such that when the clutch is engaged and thereby connects a drive input of the hydrodynamic torque converter to a drive output of the hydrodynamic torque converter, and when a service brake is actuated, the clutch is disengaged thereby separating a drive input of the hydrodynamic torque converter from a drive output of the hydrodynamic torque converter. The method comprises the steps of, when the service brake is actuated, actuating the clutch in the engaging direction, and maintaining engagement of the clutch if a device for recognizing a driving status of the working machine detects that the working machine is driving downhill.

Abstract: This invention is a lock-up clutch control device for an automatic transmission, comprising lock-up clutch control means for controlling a slip amount of the lock-up clutch to a target slip amount. When a variation rate in a required load of an engine reaches or exceeds a predetermined threshold, the target slip amount is increased at a predetermined increase rate, whereupon the target slip amount, having been increased by target slip amount increasing means, is reduced at a predetermined reduction rate. At this time, the predetermined reduction rate is set to decrease as an operating condition when the variation rate of the required load reaches or exceeds the predetermined threshold approaches an operating condition in which an increase rate of a rotation speed on the automatic transmission side of a torque converter relative to an increase in the required load is low.