Vehicle drive system and vehicle controlling method

A drive system for a vehicle, comprising:

• an engine,
• a drive wheel,
• a generator connected to the engine,
• a motor connected to the drive wheel,
• a battery electrically connected to the generator and the motor,
• a sensor which detects an accelerator depression amount,
• a sensor which detects a vehicle speed,
• a sensor which detects an engine rotation speed,
• a sensor which detects a motor rotation speed and
• a controller functioning to:
• compute a target drive power based on the accelerator depression amount and vehicle speed,
• compute a required motor power by correcting the target drive power by the efficiency of the motor,
• set a target generated power according to the required motor power,
• compute a target engine power by correcting the target generated power by the efficiency of the generator,
• set a reserve drive power in preparation for an acceleration demand,
• compute a minimum needed power by adding the reserve drive power to the target engine power,
• compute a best fuel cost-performance rotation speed based on the target engine power and best fuel cost-performance power characteristics of the engine,
• compute a minimum needed rotation speed based on the minimum needed power and maximum power characteristics of the engine,
• compare the best fuel cost-performance rotation speed and minimum needed rotation speed, and select the larger as the target rotation speed of the generator,
• control the torque of the motor based on the motor rotation speed and target drive power,
• control the rotation speed of the generator based on the target rotation speed, and
• control the torque of the engine based on the engine rotation speed and target engine power.

A drive system for a vehicle, comprising:

• an engine,
• a drive wheel,
• a continuously variable transmission provided between the engine and the drive wheel,
• a motor connected to either one of the engine and drive wheel,
• a battery electrically connected to the motor,
• a sensor which detects an accelerator depression amount,
• a sensor which detects a vehicle speed,
• a sensor which detects an engine rotation speed, and
• a controller functioning to:
• compute a target drive power based on the accelerator depression amount and vehicle speed,
• set a target engine power according to the target drive power,
• set a reserve drive power in preparation for an acceleration demand,
• compute a minimum needed power by subtracting an available discharge power of the battery from a value obtained by adding the reserve drive power to the target engine power,
• compute a best fuel cost-performance rotation speed based on the target engine power and the best fuel cost-performance power characteristics of the engine,
• compute a minimum needed rotation speed based on the minimum needed power and the maximum power characteristics of the engine,
• compare the best fuel cost-performance rotation speed and minimum needed rotation speed, and select the larger as the target input rotation speed of the transmission,
• compute the maximum power of the engine based on the engine rotation speed,
• compare the target engine power with the maximum engine power, and select the smaller as a final value of the target engine power,
• control the torque of the motor based on the target drive power and the final value of the target engine power, and
• control the torque of the engine based on the engine rotation speed and the final value of the target engine power.

A drive system for a vehicle, comprising:

• an engine,
• a drive wheel,
• a continuously variable transmission provided between the engine and the drive wheel,
• means for detecting an accelerator depression amount,
• means for detecting a vehicle speed,
• means for detecting an engine rotation speed,
• means for computing a target drive power based on the accelerator depression amount and vehicle speed,
• means for setting a reserve drive power in preparation for an acceleration demand,
• means for computing a minimum needed power by adding the reserve drive power to the target drive power,
• means for computing a best fuel cost-performance rotation speed based on the target drive power and best fuel cost-performance power characteristics of the engine,
• means for computing a minimum needed rotation speed based on the minimum needed power and maximum power characteristics of the engine,
• means for comparing the best fuel cost-performance rotation speed and minimum needed rotation speed, and selecting the larger as the target input rotation speed of the transmission,
• means for controlling the speed ratio of the transmission based on the vehicle speed and target input rotation speed, and
• means for controlling the torque of the engine based on the engine rotation speed and target drive power.

A drive system for a vehicle, comprising:

• an engine,
• a drive wheel,
• a generator connected to the engine,
• a motor connected to the drive wheel,
• a battery electrically connected to the generator and the motor,
• means for detecting an accelerator depression amount,
• means for detecting a vehicle speed,
• means for detecting an engine rotation speed,
• means for detecting a motor rotation speed,
• means for computing a target drive power based on the accelerator depression amount and vehicle speed,
• means for computing a required motor power by correcting the target drive power by the efficiency of the motor,
• means for setting a target generated power according to the required motor power,
• means for computing a target engine power by correcting the target generated power by the efficiency of the generator,
• means for setting a reserve drive power in preparation for an acceleration demand,
• means for computing a minimum needed power by adding the reserve drive power to the target engine power,
• means for computing a best fuel cost-performance rotation speed based on the target engine power and best fuel cost-performance power characteristics of the engine,
• means for computing a minimum needed rotation speed based on the minimum needed power and maximum power characteristics of the engine,
• means for comparing the best fuel cost-performance rotation speed and minimum needed rotation speed, and selecting the larger as the target rotation speed of the generator,
• means for controlling the torque of the motor based on the motor rotation speed and target drive power,
• means for controlling the rotation speed of the generator based on the target rotation speed, and
• means for controlling the torque of the engine based on the engine rotation speed and target engine power.

A drive system for a vehicle, comprising:

• an engine,
• a drive wheel,
• a continuously variable transmission provided between the engine and the drive wheel,
• a motor connected to either one of the engine and drive wheel,
• a battery electrically connected to the motor,
• means for detecting an accelerator depression amount,
• means for detecting a vehicle speed,
• means for detecting an engine rotation speed,
• means for computing a target drive power based on the accelerator depression amount and vehicle speed,
• means for setting a target engine power according to the target drive power,
• means for setting a reserve drive power in preparation for an acceleration demand,
• means for computing a minimum needed power by subtracting an available discharge power of the battery from a value obtained by adding the reserve drive power to the target engine power,
• means for computing a best fuel cost-performance rotation speed based on the target engine power and the best fuel cost-performance power characteristics of the engine,
• means for computing a minimum needed rotation speed based on the minimum needed power and the maximum power characteristics of the engine,
• means for comparing the best fuel cost-performance rotation speed and minimum needed rotation speed, and select the larger as the target input rotation speed of the transmission,
• means for computing the maximum power of the engine based on the engine rotation speed,
• means for comparing the target engine power with the maximum engine power, and selecting the smaller as a final value of the target engine power,
• means for controlling the torque of the motor based on the target drive power and the final value of the target engine power, and
• means for controlling the torque of the engine based on the engine rotation speed and the final value of the target engine power.

A vehicle control method used for a vehicle including an engine, a drive wheel and a continuously variable transmission provided between the engine and the drive wheel, the method comprising:

• computing a target drive power based on an accelerator depression amount and vehicle speed,
• setting a reserve drive power in preparation for an acceleration demand,
• computing a minimum needed power by adding the reserve drive power to the target drive power,
• computing a best fuel cost-performance rotation speed based on the target drive power and best fuel cost-performance power characteristics of the engine,
• computing a minimum needed rotation speed based on the minimum needed power and maximum power characteristics of the engine,
• comparing the best fuel cost-performance rotation speed and minimum needed rotation speed, and selecting the larger as the target input rotation speed of the transmission,
• controlling the speed ratio of the transmission based on the vehicle speed and target input rotation speed, and
• controlling the torque of the engine based on an engine rotation speed and target drive power.

A vehicle control method used for a vehicle including an engine, a drive wheel, a generator connected to the engine, a motor connected to the drive wheel and a battery electrically connected to the generator and the motor, the method comprising:

• computing a target drive power based on an accelerator depression amount and vehicle speed,
• computing a required motor power by correcting the target drive power by the efficiency of the motor,
• setting a target generated power according to the required motor power,
• computing a target engine power by correcting the target generated power by the efficiency of the generator,
• setting a reserve drive power in preparation for an acceleration demand,
• computing a minimum needed power by adding the reserve drive power to the target engine power,
• computing a best fuel cost-performance rotation speed based on the target engine power and best fuel cost-performance power characteristics of the engine,
• computing a minimum needed rotation speed based on the minimum needed power and maximum power characteristics of the engine,
• comparing the best fuel cost-performance rotation speed and minimum needed rotation speed, and selecting the larger as the target rotation speed of the generator,
• controlling the torque of the motor based on a motor rotation speed and target drive power,
• controlling the rotation speed of the generator based on the target rotation speed, and
• controlling the torque of the engine based on an engine rotation speed and target engine power.

A vehicle control method used for a vehicle including an engine, a drive wheel, a continuously variable transmission provided between the engine and the drive wheel, a motor connected to either one of the engine and drive wheel and a battery electrically connected to the motor, the method comprising:

• computing a target drive power based on an accelerator depression amount and vehicle speed,
• setting a target engine power according to the target drive power,
• setting a reserve drive power for vehicle acceleration in preparation for an acceleration demand,
• computing a minimum needed power by subtracting an available discharge power of the battery from a value obtained by adding the reserve drive power to the target engine power,
• computing a best fuel cost-performance rotation speed based on the target engine power and the best fuel cost-performance power characteristics of the engine,
• computing a minimum needed rotation speed based on the minimum needed power and the maximum power characteristics of the engine,
• comparing the best fuel cost-performance rotation speed and minimum needed rotation speed, and select the larger as the target input rotation speed of the transmission,
• computing the maximum power of the engine based on an engine rotation speed,
• comparing the target engine power with the maximum engine power, and selecting the smaller as a final value of the target engine power,
• controlling the torque of the motor based on the target drive power and the final value of the target engine power, and
• controlling the torque of the engine based on the engine rotation speed and the final value of the target engine power.