Electric Powertrain System Description
For locations of each component on vehicle, refer to Component Location Index .
The electric powertrain system is powered by high voltage motors and the engine. The system switches the driving power depending on driving conditions or by the manual operation of the EV switch and enables driving with the use of optimal available power. Major components are the engine, the two high voltage motors, the power control unit (PCU), the high voltage battery, and the battery power cable.
Control
The electric powertrain system operates during EV driving mode and hybrid driving mode. When EV driving mode is selected, the PCU sends power from the high voltage battery to the traction motor located within the transmission (e-CVT), and the vehicle is propelled by the traction motor. The engine drives the generator motor to generate electrical power. The generated electric power is supplied to the traction motor and charging of the high voltage battery depends on current driving conditions. While driving with the electric powertrain system, the high voltage battery is recharged depending on driving conditions. When recharging, the inverter sends the power that was generated from the high voltage motor in the transmission (e-CVT) to the high voltage battery.
EV Switch
The EV switch allows the driver to select EV driving mode when vehicle conditions allow for the use of EV driving mode. When the EV switch is pressed, the PCM determines if the current vehicle condition is capable of driving in EV driving mode. If EV driving mode drive is possible, the driving mode changes to EV driving mode, and the EV mode indicator on the gauge control module illuminates. If EV driving mode is not possible, the vehicle is kept in current hybrid driving mode, and the reason is displayed in the gauge control module.
Driving Modes
The electric powertrain system has the following driving modes: EV driving mode, HV driving mode, and engine driving mode. The available driving modes are determined and selected by the PCM depending on the vehicle's current condition. EV driving mode can be manually selected by the driver and is available based on current vehicle condition. When the vehicle is driven at low speeds, and during regenerative braking, the electric powertrain system operates in the EV driving mode. During high-load conditions such as acceleration, the system switches to an HV driving mode that uses both the electric motor and the internal combustion engine. At high speeds, the system enters the engine driving mode, using the gasoline engine to propel the vehicle.
EV Driving Mode
When EV driving mode has been selected, the vehicle's drive propulsion and regenerative braking is performed by the traction motor only. The EV driving mode operates at a specific vehicle speed range and during low load conditions. The EV driving mode maximum speed is 81 mph (130 km/h), depending on the battery state of charge.
EV Idle Stop Mode
During EV idle stop mode, the traction motor, generator motor, and engine are all stopped. At this time, the high voltage battery supplies power to various devices of the vehicle.
EV Drive Mode
During EV drive mode, the traction motor supplies driving force. The generator motor and the engine do not operate. At this time, the high voltage battery energizes the traction motor.
Regeneration Mode
The regeneration mode is used during deceleration. The engine and generator motor are in a stopped condition, and the traction motor generates power that is supplied to the high voltage battery.
HV Driving Mode
While driving in the HV driving mode during acceleration, the engine powers the vehicle by activating the generator motor to generate power. The generated power is used to activate the traction motor to drive the vehicle. Depending on the battery's state of charge and the load condition of the traction motor, the high voltage battery is recharged while driving.
e-CVT Charge Mode
The e-CVT charge mode is used at vehicle speed ranges suitable for charging, and its activation range varies depending on the state of charge of the high voltage battery. During e-CVT charge mode, the engine energizes the generator motor to send electric power to the high voltage battery. The traction motor provides driving power to the drive wheel, using the electric power from generator motor. The engine is actively controlled to operate at optimum RPM ranges according to driving conditions. The generator motor generates more power than what is required by the traction motor to drive the vehicle. Generated power not used by the traction motor is used to recharge the high voltage battery.
e-CVT Assist Mode
The e-CVT assist mode is primarily used during acceleration, and its activation range varies depending on the high voltage battery state of charge. The driving power during e-CVT assist mode is similar to that of the e-CVT drive mode. The engine energizes the generator motor, and the traction motor provides the driving power to the drive wheel. During e-CVT assist mode, the traction motor sends a large amount of torque to the drive wheel, therefore requiring more electric power as compared with other modes. The engine activates the generator at optimum RPM ranges, and available electric power is used directly by the traction motor. If the generator motor generates insufficient power to accommodate the needs of the traction motor, additional power is supplied from the high voltage battery.
Engine Driving Mode
The engine driving mode uses the power of the engine only at high speeds and low loads. The engine driving mode is primarily used during high-speed cruising. The operating range of the engine driving mode varies depending on the high voltage battery state of charge, driving force conditions and current speed of the vehicle.
Engine Drive Mode
During engine drive mode, the engine output is supplied to the drive wheel and the traction motor. This allows the vehicle to be mechanically driven by the engine, while the high voltage battery is charged with power created by the traction motor. The generator motor is not operated during engine drive mode.