A method of substantially preventing road speed excursions while traversing a road grade includes: determining, by a controller, a predicted over speed for a vehicle during an upcoming downhill grade based on a difference between a predicted engine braking power of the vehicle and an amount of braking power that substantially prevents a speed of the vehicle from exceeding a speed threshold; and responsive to the determination, controlling, by the controller, one or more components of the vehicle to substantially prevent the vehicle from exceeding the speed threshold.

A transmission control device (4) includes: a gear ratio calculating unit (4a) for calculating a target gear ratio of a transmission (2) based on a gear ratio control mode, to thereby control the transmission; an electric motor drive torque calculating unit (4b) for calculating a drive torque of an electric motor (9) based on the gear ratio control mode when drive of the electric motor (9) is permitted; and an engine torque calculating unit (4c) for calculating an output torque of an engine (1) based on the gear ratio control mode so as to achieve a best fuel efficiency operation state. The gear ratio calculating unit (4a) switches processing of calculating a gear ratio based on whether or not the drive of the electric motor (9) is permitted.

An apparatus and a method for controlling an engine operating point of a hybrid electric vehicle are provided to determine charging and discharging tendency based on a moving average of an engine torque and a demand torque as well as a dynamical event capture. The method includes detecting a demand torque of a driver and determining a charging and discharging tendency by calculating a moving average based on the demand torque. System efficiency is then reflected using a dynamical event capture and the charging and discharging tendency is leveled. A compensation amount of the operating point is also determined based on the leveling of the charging and discharging tendency and the operating point of the hybrid electric vehicle is adjusted based on the compensation amount of the operating point.

A control device for a continuously variable transmission includes first, second, and third controllers. The first controller controls, in response to a first speed control request for controlling a traveling speed of a vehicle for a predetermined state, a gear ratio of the continuously variable transmission such that a rotational speed of a drive power source approaches a set rotational speed. The second controller controls, in response to a second speed control request issued while the first controller is controlling the gear ratio, the gear ratio based on the rotational speed and the gear ratio. The third controller changes, when the rotational speed changes as a result of the second controller controlling the gear ratio, torque of the drive power source based on torque and the rotational speed of the drive power source before the gear ratio is changed and a target rotational speed of the drive power source.

A hybrid vehicle includes an engine, a first motor, a planetary gear mechanism, a second motor, a battery, and an electronic control unit. The electronic control unit is configured to: control the engine, the first motor, and the second motor such that the hybrid vehicle travels using a required driving force; set a target rotation speed on a basis of the depression amount of the accelerator pedal, the vehicle speed, and a shift stage such that the target rotation speed of the engine increases as the depression amount of the accelerator pedal increases; set an upper-limit driving force; and control the engine, the first motor, and the second motor such that the engine operates at the target rotation speed and the smaller driving force of the upper-limit driving force and the required driving force is output to the drive shaft.

A hybrid vehicle includes an engine, a first motor, a planetary gear mechanism, a second motor, a battery, and an electronic control unit. The electronic control unit is configured to: set a shift stage based on a depression amount of an accelerator and a vehicle speed or a driver's operation; set a base driving force based on the degree of the depression amount of the accelerator, the vehicle speed, and a target rotation speed; set a correction driving force such that the correction driving force increases with an increase in elapsed time after upshifting or an increase in the vehicle speed after upshifting when the shift stage upshifts; and control the engine, the first motor, and the second motor such that a driving force obtained by correcting the base driving force using the correction driving force is output to the drive shaft.

A transmission controller includes a processor configured to set acceleration/deceleration start timing at which a vehicle starts accelerating or decelerating, based on at least one of a sensor signal representing the situation around the vehicle, the current position of the vehicle, a map including information on a road being traveled by the vehicle, and operation of the vehicle by a driver, downshift a second transmission of a power train including two motors and an engine before the acceleration/deceleration start timing, and control the power train to vary first and second gear ratios of a first transmission so as to keep the RPM of the engine constant. The first transmission is capable of steplessly varying the first and second gear ratios, which are gear ratios between one of the motors and the engine and between the other motor and the engine, respectively.

A method for operating a powertrain of a hybrid vehicle is provided. The method includes outputting via a controller an engine speed command that is based on a predicted impeller speed of a torque converter and corresponds to the accelerator tip-in to output a torque from the engine to wheels of the vehicle in response to detection of an accelerator pedal tip-in greater than a predetermined threshold. The method may also include accessing a history of impeller speed outputs of the hybrid vehicle to obtain the predicted impeller speed. The engine speed command may set engine speed substantially equal to or greater than the predicted impeller speed. The predetermined threshold may be based on a driver requested torque output of the wheels in which torque from the torque converter to the wheels results in saturation.

Methods and systems are provided for an electric drive train of a hybrid electric vehicle (HEV). In one example, the electric drive train may include a four-node planetary gear set with a first motor coupled to a first input node, a second motor coupled to a second input node and an engine coupled to a third input node of the planetary gear set. The third node is positioned between the first and second input nodes. Torque delivered to each input node is summed at an output node of the four-node planetary gear set.

Systems and methods for improving operation of a driveline disconnect clutch for a hybrid vehicle shifting are presented. In one example, pressure of a working fluid supplied to the driveline disconnect clutch is adjusted in response to a rate of change in accelerator pedal position. Further, pressure of the working fluid may be decreased responsive to selected operating conditions.