A control apparatus includes a first determination section determining whether a power-supply voltage has decreased below a first threshold value, an interruption section interrupting a current flow to an inverter if the voltage has decreased below the first threshold value, a second determination section that determining whether the power-supply voltage has increased above a second threshold value, an interruption releasing section releasing the interruption based on the fact that the voltage has increased above the second threshold value, a count section counting the number of interruptions, a limiting section determining whether the decrease in the power-supply voltage is caused by a first factor of an electric rotating machine or a second factor, and limits the counting if the decrease in the power-supply voltage is caused by the second factor, and a third determination section determining whether the interruption is allowed to be released based on the number of interruptions.

A method and an apparatus for controlling a mild hybrid electric vehicle are provided. The method includes detecting data for operating the vehicle and determining a target torque of an engine based on the detected data. Additionally, the method includes determining whether an operating condition of a limiting logic of a combustion torque of the engine is satisfied based on a temperature of coolant of the engine and operating the limiting logic when the operating condition of the limiting logic is satisfied. A first available combustion torque of the engine is determined based on a speed of the engine and the temperature of the coolant when the limiting logic is operated and a target torque of a MHSG is determined based on the target torque of the engine and the first available combustion torque of the engine. The MHSG is then operated to generate the target torque of the MHSG.

A driving mode control method and apparatus of a hybrid electric vehicle are provided. The driving mode control method includes decreasing a torque of an engine when a first driving mode in which both the engine and a first motor are driven is switched to a second driving mode driven by the first motor and applying a torque of a second motor. A clutch is then opened when a difference between the engine torque and the second motor torque is less than a first threshold torque.

An engine starting control system for hybrid vehicles is provided to prevent a temporal drop in drive force when starting an engine. The control system maintains an operating mode of a switching mechanism when starting the engine by the first motor, in a case that the vehicle is propelled in the forward direction by the first motor and that the switching mechanism is in a second mode, or in a case that the vehicle is propelled in the reverse direction by the first motor and that the switching mechanism is in the first mode. Thereafter, the control system increases a rotational speed of the engine to a self-sustaining speed, switches the operating mode of the switching mechanism, and increases torque of the engine.

At the time of starting up an engine (9) using an assist motor generator (10), a main controller (28) lowers a lower limit value in a charge/discharge range of an electricity storage device (19) from a first lower limit value (min1) to a second lower limit value (min2) through an energy management control part (28B). The main controller (28) heightens the lower limit value in the charge/discharge range of an electricity storage device (19) from the second lower limit value (min2) to the first lower limit value (min1) when the start of the engine (9) is completed. Further, the main controller (28) displays engine stop prohibition information on a display device (30) when the start of the engine (9) is completed and when an SOC of the electricity storage device (19) falls below the first lower limit value (min1).

A hybrid vehicle system includes: an engine that is capable of outputting a torque to be transmitted to a driving wheel; a first motor generator that is provided in a coupled manner to the engine and that is capable of outputting a torque to be transmitted to the driving wheel; a transmission that converts a torque output from one or both of the engine and the first motor generator at a predetermined transmission gear ratio; a transmission clutch that is capable of switching on and off power transmission between the first motor generator and the transmission; a second motor generator that is capable of outputting a torque to be transmitted to the driving wheel in a state where the transmission clutch is disengaged; and an oil pump that is coupled to a motor shaft of the first motor generator and that is driven by rotation of the motor shaft.

A motive power system includes a first energy storage, a second energy storage, an actuator, an internal combustion engine, a power transmission circuit, and circuitry. The circuitry is configured to control the power transmission circuit in a charge-depleting mode such that the first energy storage supplies to the actuator a first electric energy that is stored in the first energy storage with a first charge rate range and the second energy storage supplies to the actuator a second electric energy that is stored in the second energy storage with a second charge rate range. The first charge rate range is larger than the second charge rate range.

When an engine start command is generated to an engine that is in a stopped state, engine start control for cranking the engine and starting fuel combustion after increasing the engine speed is performed. In the engine start control, one of a first start pattern in which an initial combustion speed is higher than a resonance speed of the engine, and a second start pattern in which the initial combustion speed is lower than the resonance speed of the engine is selected according to the speed ratio (gear position) of a transmission. Cranking torque in the second start pattern is lower than the cranking torque in the first start pattern.

A hybrid power module efficiently delivers both hydraulic power and electric power. The hybrid power module may regenerate and store energy for later use. The module includes and engine and an electric motor for driving a hydraulic pump. The electric motor is operable as a starter motor for the engine and as an assist motor cooperating with the engine to power the hydraulic pump to improve dynamic response of the hydraulic pump. The module also includes an electric power source which may have an energy storage unit, and the electric motor may be operated as an electric generator providing electric energy to the energy storage unit.

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.