A control system for preventing engine stall due to slippage of a wheel during propulsion in a fixed mode in which an engine and the wheel are rotated at a fixed ratio. When a wheel slips in a first mode in which an engine and the wheel are rotated at a predetermined ratio, an operating mode is shifted to a second mode in which a torque transmission between the engine and the wheel is interrupted and the vehicle is propelled by torque of driving machine connected to the wheel, or to a third mode in which the vehicle is propelled by delivering torque of the engine to the wheel while establishing a reaction torque by a predetermined rotary member.

To inhibit clutch engagement during an engine restart from affecting cooperative regenerative braking control and switching of braking in a hybrid vehicle having a P2 module onboard, a control system for the hybrid vehicle includes an engine, a motor, a K0 clutch, drive shafts, a hydraulic friction brake system, and a controller capable of performing cooperative regenerative braking control. When start of the engine is requested during the cooperative regenerative braking control, the controller performs a first process of transitioning to braking only by the frictional brake system, a second process of raising an engine revolution speed while engagement of the K0 clutch is initiated after completion of transitioning to the braking, and a third process of controlling the engine to resume operating at a timing after the engine revolution speed increases to match a motor revolution speed after the engagement of the K0 clutch is initiated.

A system comprises a generator and an engine coupled thereto. The engine is configured to provide mechanical power to the generator. A controller is coupled to the engine and the generator and is configured to compare an engine operating parameter value to a load demand value indicative of a load exerted by the generator on the engine. The controller determines that the engine operating parameter value fails to match the load demand value. The controller determines an engine operating parameter threshold value at which the engine operating parameter value failed to match the load demand value, and sets the engine operating parameter threshold value as a maximum allowable engine operating parameter value for the engine.

A slip control method and arrangement for a driveline is described herein. The driveline includes a clutch that is so controlled as to slip when a torque higher than the usable torque attempts to pass through. Accordingly, the clutch prevents the prime mover from stalling.

Since a supercharging pressure from a supercharger decreases when an actual rotation speed difference is equal to or less than a margin rotation speed difference, a response delay of an engine torque due to a response delay of the supercharging pressure in a high rotation curbing control unit can be appropriately curbed. A shortage of the engine torque with respect to a required engine torque due to a decrease in the supercharging pressure by a supercharging pressure decreasing unit is compensated for using an torque of a second rotary machine. Accordingly, it is possible to curb a decrease in power performance due to a decrease in the supercharging pressure and to prevent an engine rotation speed from falling into a high-rotation state in which the engine rotation speed exceeds a maximum rotation speed.

A method of substantially preventing road speed excursions while traversing a road grade event includes receiving, by a controller, vehicle operations data regarding operation of a vehicle and road grade data regarding an upcoming road grade of a path ahead of the vehicle. The method additionally includes determining, by the controller, an amount of braking power that substantially prevents the vehicle from exceeding a speed threshold regarding operation of the vehicle based on the road grade and vehicle operations data, and determining an amount of engine braking power based on a current transmission setting. The method further includes controlling, by the controller, a transmission setting in response to a determination that the amount of engine braking power is less than the amount of braking power.

When it is determined that there is a likelihood of occurrence of an abnormality in a supercharger, a maximum engine rotation speed and a maximum MG2 rotation speed are changed to a low rotation speed side and operating points of an engine and a rotary machine are controlled such that an engine rotation speed and an MG2 rotation speed are respectively within ranges which do not exceed the changed maximum rotation speeds. Accordingly, even when the supercharger does not operate normally and an abnormal increase in a supercharging pressure occurs, it is possible to curb a high-rotation state of the engine rotation speed and the MG2 rotation speed. As a result, even when an abnormal increase in the supercharging pressure occurs, it is possible to curb a decrease in durability of components.

Since a maximum rotation speed is set to a lower value when a supercharging pressure from a supercharger is high than when the supercharging pressure is low, an engine torque is decreased at a relatively low engine rotation speed and the engine rotation speed is less likely to fall into a high-rotation state. Since the maximum rotation speed is set to a relatively high value when the supercharging pressure is relatively low and the engine rotation speed is less likely to fall into a high-rotation state, the engine torque is not decreased at a relatively high engine rotation speed and power performance can be easily secured. Accordingly, it is possible to curb a decrease in power performance due to a decrease in the engine torque and to prevent the engine rotation speed from falling into a high-rotation state.

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.

A method of substantially preventing road speed excursions while traversing a road grade event includes receiving, by a controller, vehicle operations data regarding operation of a vehicle and road grade data regarding an upcoming road grade of a path ahead of the vehicle. The method additionally includes determining, by the controller, an amount of braking power that substantially prevents the vehicle from exceeding a speed threshold regarding operation of the vehicle based on the road grade and vehicle operations data, and determining an amount of engine braking power based on a current transmission setting. The method further includes controlling, by the controller, a transmission setting in response to a determination that the amount of engine braking power is less than the amount of braking power.