Abstract: A hybrid vehicle includes: an engine; a motor; a drive system battery connected to a drive system power line; an auxiliary system battery connected to an auxiliary system power line; a bidirectional power converter configured to step down power on the drive system power line to supply the stepped-down power to the auxiliary system power line, and configured to boost power on the auxiliary system power line to supply the boosted power to the drive system power line; and a control device. The control device is configured to, upon a cold start in which the engine is started, control the engine, the motor, and the bidirectional power converter to cause the motor to crank the engine while causing the bidirectional power converter to boost the power on the auxiliary system power line to supply the boosted power to the drive system power line.

Abstract: A hybrid vehicle includes: an engine; a motor; a drive system battery connected to a drive system power line; an auxiliary system battery connected to an auxiliary system power line; a bidirectional power converter configured to step down power on the drive system power line to supply the stepped-down power to the auxiliary system power line, and configured to boost power on the auxiliary system power line to supply the boosted power to the drive system power line; and a control device. The control device is configured to, upon a cold start in which the engine is started, control the engine, the motor, and the bidirectional power converter to cause the motor to crank the engine while causing the bidirectional power converter to boost the power on the auxiliary system power line to supply the boosted power to the drive system power line.

Abstract: In a state of reverse driving with load operation of an engine, an upper limit torque Temax of the engine is set to cause a total torque of a torque demand Tr* and a cancellation torque for cancelling a torque applied to a driveshaft accompanied with load operation of the engine to be output from a second motor to the driveshaft. A product of the upper limit torque Temax of the engine and an upper limit rotation speed Nemax of the engine is set to an upper limit power Pemax. A target power Pe* of the engine is then set in a range of not greater than the upper limit power Pemax. The engine, a first motor and the second motor are then controlled such as to cause the target power Pe* to be output from the engine and such as to output the torque demand Tr* to the driveshaft.

Abstract: In a state of reverse driving with load operation of an engine, an upper limit torque Temax of the engine is set to cause a total torque of a torque demand Tr* and a cancellation torque for cancelling a torque applied to a driveshaft accompanied with load operation of the engine to be output from a second motor to the driveshaft. A product of the upper limit torque Temax of the engine and an upper limit rotation speed Nemax of the engine is set to an upper limit power Pemax. A target power Pe* of the engine is then set in a range of not greater than the upper limit power Pemax. The engine, a first motor and the second motor are then controlled such as to cause the target power Pe* to be output from the engine and such as to output the torque demand Tr* to the driveshaft.

Abstract: When the temperature of coolant in an engine is greater than or equal to a half-warm-up determination value, an engine cooling control section opens a valve to mix the coolant in two coolant circuits. Accordingly, even if the temperature of the coolant in the engine fluctuates due to mixing coolants at different temperatures, such fluctuation occurs in a temperature range lower than the determination value for the warm-up completion of the engine. This prevents a control procedure for the time before the warm-up completion and a control procedure for the time after such completion from being performed in a repeating, alternating manner. As a result, when the coolant circulating in the first coolant circuit and the coolant circulating in the second coolant circuit are mixed together, control that should be performed based on the coolant temperature in the engine is carried out without hindrance.

Abstract: The coolant of the first coolant circuit is mixed with the coolant of the second coolant circuit when the temperature detected by the coolant temperature sensor becomes greater than or equal to a semi-warm-up determination value, which is set to a temperature that is lower than a warm-up completion determination value of the engine. Accordingly, when the heat generated by the engine and the heat recovered by the exhaust heat recovery device from the in-vehicle heat source are independently used to increase the temperature of the coolant, control can be executed without any trouble based on the coolant temperature even when mixing the coolant of the engine with the coolant of the exhaust heat recovery device, in which the temperatures have been increased independently.

Abstract: When the temperature of coolant in an engine is greater than or equal to a half-warm-up determination value, which is set to a value smaller than a determination value for warm-up completion of the engine, an engine cooling control section opens a valve to mix the coolant in two coolant circuits. Accordingly, even if the temperature of the coolant in the engine fluctuates due to mixing coolants at different temperatures, such fluctuation occurs in a temperature range lower than the determination value for the warm-up completion of the engine. This prevents a control procedure for the time before the warm-up completion and a control procedure for the time after such completion from being performed in a repeating, alternating manner. As a result, when the coolant circulating in the first coolant circuit and the coolant circulating in the second coolant circuit are mixed together, control that should be performed based on the coolant temperature in the engine is carried out without hindrance.