Controller and control method for hybrid electric vehicle

A controller for a hybrid electric vehicle, wherein

• the hybrid electric vehicle includes an engine and a motor generator as a power source, the engine including a crankshaft, and the motor generator including a driving shaft,
• the hybrid electric vehicle further includes a clutch between the crankshaft and the driving shaft,
• the controller comprises circuitry that controls the engine, the motor generator, and the clutch, and
• the circuitry is configured to execute:
• a first starting process that starts, when starting the engine under a condition in which an increase amount of a torque request value is less than an increase amount determination value, combustion in the engine after increasing an engine rotation speed to a motor rotation speed by engaging the clutch, the torque request value being a request value of torque for the power source, the engine rotation speed being a rotation speed of the crankshaft, and the motor rotation speed being a rotation speed of the driving shaft;
• and
• a second starting process that starts, when starting the engine under a condition in which the increase amount of the torque request value is greater than or equal to the increase amount determination value, combustion in the engine after the crankshaft starts to be rotated by engaging the clutch, the combustion being started before the engine rotation speed reaches the motor rotation speed.