Since a maximum rotation speed of a second rotary machine is set to a lower value when a supercharging pressure is high than when the supercharging pressure is low, an engine torque decreases with an rotation speed of the second rotary machine which is relatively low and the rotation speed is less likely to fall into a high-rotation state. When the supercharging pressure is relatively low and the rotation speed is less likely to reach an upper-limit rotation speed of the second rotary machine, the maximum rotation speed is set to a relatively high value. Accordingly, the engine torque does not decrease to the rotation speed which is relatively high and power performance can be easily secured. As a result, it is possible to prevent a decrease in power performance due to the decrease in the engine torque and to prevent the rotation speed from falling into a high-rotation state.

Vehicle designers are largely walking away from internal-combustion engines to battery and electric motors. Until infrastructure is developed to support total electrification, hybrid-electric vehicles (HEVs) which include both an internal combustion engine and an electric machine are a step toward electrification and higher system fuel efficiency while retaining the expected vehicle range. To obtain even higher system fuel efficiency combustion modes that provide higher efficiency than spark-ignition (SI) operation can be used in HEVs. A problem with such combustion modes is that they cannot be used over as wide an operating range as SI operation and transitions among modes is slow and cumbersome. By having the ICE installed into a HEV be a multi-combustion mode engine and having the EM to coordinate mode switches to be smooth, the high fuel-efficiency of alternative combustion modes can be exploited while providing smooth operation expected by vehicle users.

The hybrid vehicle includes an engine, a motor connected to the engine, and an electronic control unit configured to control the motor to execute motoring to rotate a crankshaft of the engine. The electronic control unit is configured to execute speed-drop offset control when a rotation speed of the engine falls below a first rotation speed that is lower than a self-sustaining rotation speed of the engine while the engine is operated in a self-sustaining manner at the self-sustaining rotation speed.

Methods and systems for a hydromechanical transmission are provided herein. In one example, a vehicle system is provided that includes a hydromechanical transmission with a power-take off (PTO) that is designed to rotationally couple to an implement. The vehicle system further includes an engine coupled to the hydromechanical transmission and a power-management control unit configured to, during a drive or coast condition, cause the power-management control unit to: determine a net available power for the hydromechanical transmission and manage a power flow between the hydromechanical transmission, a drive axle, and the implement based on the net available power.

In the solution put forth, a pressure level of a pump in a hydraulic transmission system of a hydraulic working machine, or power that is feedable to an electric drive motor of an electric working machine is monitored, and/or the rotation speed at the output of the drive motor of the working machine and the rotation of moving means of the working machine are monitored. The pressure level of the hydraulic power transmission pump, or the power feedable to an electric drive motor, is compared with a lower threshold value to detect a fault situation, and/or the rotation speed at the output of the drive motor is compared with the rotation of the moving means also to detect a fault situation. In case a fault situation is detected, the braking system of the working machine is controlled to apply the brakes.

A method in a control arrangement of a vehicle and a control arrangement for a vehicle for downshifting gears in an uphill slope are presented. The method comprises, when the vehicle is travelling in an uphill slope using an initial gear of the vehicle's automated manual transmission gearbox: simulating at least one speed profile for a downshift to, and a usage of, at least one gear; determining that a minimal speed of each one of the at least one simulated speed profile has a value indicating that the actual speed of the vehicle will be less than or equal to zero in the uphill slope; opening a clutch before is reduced to a value less than zero; activating at least one vehicle brake; shifting vehicle's automated manual transmission gearbox to a start gear; closing the clutch; and deactivating the at least one vehicle brake.

A vehicle includes a controller configured to switch between a constant speed traveling mode in which a vehicle speed is held constant and an inertial traveling mode in which a prime mover is stopped or in an idling state, and a clutch apparatus configured to connect and disconnect power transmission between the prime mover and an output target, and the controller controls the clutch apparatus and decreases a clutch capacity so as to transit to the inertial traveling mode when detected that the vehicle is traveling on a downhill road during the constant speed traveling mode, and the controller controls the clutch apparatus and increases the clutch capacity so as to transit to the constant speed traveling mode when detected that the vehicle traveling on the downhill road has terminated.

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 hydraulic system for a work machine includes a prime mover, a setup member, a hydraulic pump, an operation valve, a hydraulic device, and a memory. The memory stores first control characteristics indicating relations between the first pressure and an actual revolution speed of the prime mover, and stores a second control characteristic indicating a relation between the first pressure and the actual revolution speed of the prime mover. The hydraulic system includes a controller to set the first pressure based on the second control characteristic when a dropping amount of the actual revolution speed from the target revolution speed is less than a threshold value and to set the first pressure based on the first control characteristics determined corresponding to the target revolution speed when the dropping amount of the actual revolution speed from the target revolution speed is the threshold value or more.

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.