A determination unit in an ECU of a rough terrain vehicle determines a reverse running state in a case that an engine rotational speed of an engine decreases when a traveling drive force is generated in the rough terrain vehicle. Further, if the determination unit determines occurrence of the reverse running state, the ECU refers to a clutch hydraulic pressure map, and sets a target hydraulic pressure so as to decrease gradually over time.

In a rough terrain vehicle, at a time of preparing to start movement, in a case that a left paddle switch and a right paddle switch are operated together with an accelerator pedal, an ECU disengages a clutch of an automatic transmission, and causes an output of an engine to increase. On the other hand, at a time of starting movement, in a case that the left paddle switch and the right paddle switch are returned to their initial positions, the ECU engages the clutch and transmits the output of the engine from the engine to vehicle wheels via the automatic transmission, to thereby rapidly start movement of the rough terrain vehicle.

An upper limit charging rate is limited when a speed position of an automatic transmission is high as compared to when the speed position is low, so an engine is hard to enter a high torque state even when the speed position is high. Thus, it is possible to suppress vibrations and noise that tend to occur at the time when the engine is driven at a low rotation speed and high torque. On the other hand, the upper limit charging rate increases when the speed position is low as compared to when the speed position is high, with the result that a charging rate increases, so it is possible to keep a state of charge of a battery within an appropriate range.

The present invention relates to a work machine, in particular in the form of a dump truck or truck, comprising a traction drive unit and/or main work unit which can be driven by a drive apparatus comprising at least one electric motor. The invention further relates to a method for operating such a work machine, in accordance with the invention, the drive apparatus comprises at least one hydraulic motor supporting the electric motor, the hydraulic motor being switched in for starting the drive apparatus and being decoupled on an exceeding of a predefined speed.

A power transmission system includes first differential mechanism connected to an engine, and second differential mechanism. The first differential mechanism includes a first rotating element connected to the engine, and second and third rotating elements. The second differential mechanism includes a fourth rotating element connected to second rotating element, fifth rotating element connected to a first electric rotary machine, and sixth rotating element that is an output element of the second differential mechanism. The power transmission system further includes at least one of a first clutch and brake, and a second clutch. The first clutch is configured to releasably couple two of the first, second and third rotating elements to each other. The brake is configured to releasably couple the third rotating element to a stationary element. The second clutch is configured to releasably couple the third rotating element to one of the fifth and sixth rotating elements.

A startup control device includes a vehicle temperature sensor configured to sense a temperature of the vehicle, a vehicle startup controller configured to select the second vehicle startup mode in a low temperature state in which the temperature of the vehicle is equal to or smaller than at least a first temperature judgment value when the request of the startup of the vehicle is sensed, and to select the third vehicle startup mode in an extremely low temperature state in which the temperature of the vehicle is equal to or smaller than a second vehicle temperature judgment value which is smaller than the first temperature judgment value when the request of the startup of the vehicle is sensed.

A transmission includes an input shaft coupled to a prime mover, a countershaft, main shaft, and an output shaft, with gears between the countershaft and the main shaft. A shift actuator selectively couples the input shaft to the main shaft by rotatably coupling gears between the countershaft and the main shaft. The shift actuator is mounted on an exterior wall of a housing including the countershaft and the main shaft. A controller controls the shift actuator utilizing an actuating pulse and an opposing pulse.

A multimode clutch may be adapted for selectively connecting and disconnecting front and/or rear axles from respective internal combustion engine and electric motor powertrains connected to such front and rear driving axles in a through-the-road hybrid vehicle. For example, the engine may be part of a front axle driven powertrain connected to the front wheels, while the motor may be part of a separate rear axle driven powertrain connected to the rear wheels, or vice versa. By selective disconnection of an axle not being actively driven, a real time reduction in parasitic losses may be achieved, leading to higher overall operating efficiencies. The multimode clutch offers greater flexibility over the use of standard friction clutches; each multimode clutch may provide four distinct operational modes for accommodating a wide diversity of driving conditions. For example, bi-rotational freewheeling of the rear axle may occur whenever the motor is not in use.

A method for controlling a drivetrain of a motor vehicle is disclosed. Either a start mode for starting the reciprocating engine is activated via the driving vehicle wheel, or a coasting mode is activated for driving the reciprocating engine via the driving vehicle wheel. At least one volume-reducing stroke is executed that follows an intake stroke for at least one cylinder of the reciprocating engine with at least intermittently open cylinder. Alternately at least one volume-enlarging stroke is executed for at least one cylinder of the reciprocating engine, which is followed by a compression stroke of this cylinder, and at least one volume-reducing stroke of this cylinder, which follows an expansion stroke that follows the compression stroke, with a cylinder that is closed, if possible, in this operating mode.

A drive unit for a hybrid vehicle includes a drive assembly with an internal combustion engine and an electric motor, and a transmission featuring several sub-transmissions shifting between the drive assembly and an output. Through a planetary transmission, the electric motor is coupled to an input shaft of a first sub-transmission and an input shaft of a second sub-transmission. Through a separating clutch, the internal combustion engine is to the input shaft of the first sub-transmission and, if the separating clutch is locked, is coupled to the same element of the planetary transmission as the input shaft of the first sub-transmission. A bypass shift element works with the planetary transmission such that, with a locked bypass shift element, a torque-proof connection between the electric motor, the input shaft of the first sub-transmission and the input shaft of the second sub-transmission exist, while, with an open bypass shift element, this torque-proof connection between the electric motor and the two input shafts of the two sub-transmissions does not exist. The separating clutch is formed as a frictional-locking or positive-locking separating clutch, and the bypass shift element is formed as a frictional-locking bypass shift element.