An HV-ECU calculates requested output torque Tec based on requested power and compares the requested output torque with controlled upper limit torque Teth. When requested output torque Tec has attained to controlled upper limit torque Teth, the HV-ECU restricts output torque of engine to controlled upper limit torque Teth and calculates actual output torque Ter at that time. Then, the HV-ECU calculates a difference (differential torque Te) between controlled upper limit torque Teth and actual output torque Ter. The HV-ECU learns controlled upper limit torque Teth based on differential torque Te.

An engine includes a turbocharger that boosts suctioned air to be fed to the engine. A boost line is determined on a map representing a relationship between the rotation speed of the engine and torque generated by the engine, and the turbocharger boosts suctioned air when the torque generated by the engine indicated by an operating point on the map exceeds the boost line. An HV-ECU controls the engine and a first MG to increase the rotation speed of the engine, depending on the atmospheric pressure, before the torque generated by the engine indicated by the operating point exceeds the boost line, and when the HV-ECU increases the rotation speed of the engine, for lower atmospheric pressure the HV-ECU controls the engine and the first MG to increase the rotation speed more than for higher atmospheric pressure.

An HV-ECU performs processing including calculating estimated engine torque based on a previous value of a time constant, setting as the time constant, a first value corresponding to a forced induction range when engine torque is determined as being in the forced induction range, setting as the time constant, a second value corresponding to a non-forced induction range when engine torque is determined as not being in the forced induction range, calculating a feedforward term Tgff, calculating a feedback term Tgfb, calculating a torque command value for a first MG, and outputting a first MG torque command.

An engine system may include an engine including a plurality of intake lines through which outside air supplied to combustion chamber flows, a first electric supercharger and a second electric supercharger disposed respectively in the plurality of intake lines, a first exhaust gas recirculation (EGR) device including a first EGR line branched from an exhaust manifold and joining an intake manifold and a first EGR valve disposed in the first EGR line, and a controller determining an engine target torque according to a driving condition of the engine, setting an engine torque within an operation region of the first EGR device when the engine target torque is in a torque dead band between the operation region of the first EGR device and a non-operation region thereof, and compensating a difference value between the engine target torque and the engine torque by a hybrid electric vehicle (HEV) motor.

System and methods are provided for improving fuel economy of a hybrid vehicle. A hybrid vehicle may include an EV driving mode, where the motor alone powers the hybrid vehicle. However, use of such a driving mode may be limited to conditions involving low drive force and power requests due to motor and battery power specifications. In some circumstances, the conditions during which the motor can be used to power the hybrid vehicle can be expanded. Such conditions may include instances where the driver only seeks light accelerations for a short period of time. Such an expanded EV mode may be triggered when the hybrid vehicle is travelling a downhill grade.

A control device for a vehicle includes an opening degree sensor to detect an opening degree of a wastegate valve disposed in a bypass passage bypassing a turbine. Circuitry is configured to stop an internal combustion engine while the vehicle is driven by a motor in a motor drive mode. The circuitry is configured to calculate a target opening degree of the wastegate valve to be larger than a maximum error between the opening degree detected by the opening degree sensor and an actual opening degree of the wastegate valve. The circuitry is configured to control the wastegate valve such that the opening degree detected by the opening degree sensor is equal to the target opening degree while the vehicle is driven in the motor drive mode.

Methods and systems are provided for enabling vehicle speed control without overfilling a system battery. In one example, braking energy is applied (or recuperated) by applying a negative torque from BISG until a system battery has been sufficiently charged. Thereafter, the electrical power generated by the BISG is used to operate an electric boost assist motor, and the energy is recuperated in the form of stored compressed air.

A vehicle is a series hybrid vehicle that drives drive wheels using a travel motor by utilizing power of a power generation motor, which generates power by being driven by motive power of an internal combustion engine provided with a turbo charger. A method for controlling the vehicle includes executing a fuel cut of the internal combustion engine when excess power is greater than at least power that can be inputted in the system and the internal combustion engine is being supercharged.

A method for controlling a mild hybrid vehicle may include determining, by a controller, whether an engine of the mild hybrid vehicle operates based on a demand torque of a driver of the mild hybrid vehicle; determining, by the controller, a torque of a starter-generator of the mild hybrid vehicle that assists a torque of the engine according to the demand torque of the driver based on a temperature of a turbocharger of the mild hybrid vehicle when the engine is operated; and operating, by the controller, the starter-generator to assist the torque of the engine based on the determined torque of the starter-generator.

A method for controlling a mild hybrid vehicle may include determining, by a controller, whether an engine of the mild hybrid vehicle operates based on a demand torque of a driver of the mild hybrid vehicle; determining, by the controller, a torque of a starter-generator of the mild hybrid vehicle that assists a torque of the engine according to the demand torque of the driver based on a temperature of a turbocharger of the mild hybrid vehicle when the engine is operated; and operating, by the controller, the starter-generator to assist the torque of the engine based on the determined torque of the starter-generator.