Hybrid Control System System Description
SYSTEM
HYBRID CONTROL SYSTEM : System Description
SYSTEM DIAGRAM
HPCM INPUT/OUTPUT SIGNAL CHART
Input Signal Item
Output Signal Item
SYSTEM DESCRIPTION
HPCM controls the output of the hybrid system generated by the engine and traction motor based on the signals from the sensors and control modules. In addition, it monitors and controls the conditions of the Li-ion battery and high-voltage circuit, performs cooperative regenerative braking with the electrically-driven intelligent brake system, and performs the complete range of various hybrid system controls.
HYBRID SYSTEM OUTPUT CONTROL
To control the drive force, HPCM detects the vehicle conditions based on information from the sensors and control modules, and controls the engine and traction motor.
HPCM judges the driving conditions based on the throttle position, vehicle speed, selector lever position, and other signals, and calculates the target drive force for those conditions. Based on the calculated target drive force and the status of each system, it distributes the required output between the engine and traction motor, and transmits the command signals to each control module. When each control module receives the signal, it performs control based on the command signal from the HPCM.
NOTE:
The status of each system control can be checked from "Energy monitor" on either the "Navigation display" or combination meter "Information Display". System Description
or Base Audio.
Functions of Primary Control Modules
[EXAMPLE OF ENGINE AND TRACTION MOTOR OUTPUT CONTROL ACCORDING TO DRIVING CONDITIONS]
HPCM controls the driving mode according to a range of driving conditions. Examples of vehicle driving modes under different driving conditions are shown below.
Hybrid System Activation
When the ignition switch is turned ON, HPCM turns ON the self shut-OFF relay and activates the hybrid system.
When Vehicle is READY
- When the vehicle is READY, HPCM controls the system main relay and connects the high-voltage circuit.
System Main Relay Control System Description.
- The combination meter activates the READY to drive indicator lamp, informing the driver that the vehicle is ready to drive.
- HPCM detects the engine and Li-ion battery status based on signals from the ECM and Li-ion battery controller.
When engine is cold and Li-ion battery level is low, in order to warm the engine or charge the Li-ion battery, clutch 1 is engaged and the traction motor output is used to start the engine.
NOTE:
Even after the engine is warm or the Li-ion battery level is sufficient, in some cases the engine still may not start due to other conditions.
Normal Driving
- When starting and driving at low speed (motor driving)
- When starting and driving at low speed, the mode is motor driving in which the electrical power from the Li-ion battery is used to drive the vehicle using traction motor output torque only.
NOTE:
Motor driving may not be engaged when engine is cold and Li-ion battery level is low, or due to other conditions.
- HPCM transits the engine stop command signal to the ECM, stopping the engine and disengaging clutch 1.
It also transmits the drive command signal to the traction motor inverter, controlling the traction motor output.
- HPCM transmits the EV indicator lamp signal to the combination meter via CAN communication. When the combination meter receives the signal, it activates the EV indicator lamp.
- Low-load driving
- During low-load driving, the vehicle is driven by engine output torque, and the traction motor generates power to charge the Li-ion battery (when the Li-ion battery level is low).
- HPCM engages clutch 1 and starts the engine.
- HPCM detects the Li-ion battery status from the Li-ion battery controller, and transmits the output torque signal to the ECM to control the engine output. The traction motor inverter controls the power generation by the traction motor and charges the Li-ion battery.
Vehicle Stopped
- When the Li-ion battery level is low, engine output is used to generate power from the traction motor and charge the Li-ion battery.
NOTE:
When the Li-ion battery level is sufficient, or due to other conditions, the engine may stop.
- HPCM detects the Li-ion battery status from the Li-ion battery controller, and transmits the output torque signal to the ECM to control the engine output.
- HPCM engages clutch 1 and disengages clutch 2.
Accelerating or Load is High
- When the accelerator pedal is fully depressed, the engine output torque assists the output torque from the traction motor.
- HPCM engages clutch 1 and clutch 2 and transmits the output torque signal to the ECM and the drive command signal to the traction motor inverter, and controls the engine and traction motor output.
Deceleration Driving
When decelerating, regenerative braking uses the motive power of the drive wheels to generate power from the traction motor and charge the Li-ion battery.
Cooperative control with the electrically-driven intelligent brake system increases the amount of power generated by regenerative braking. Brake System Cooperation Control System Description for details.
Hybrid System Stop
HPCM detects the traction motor status (speed) via CAN communication from the traction motor inverter.
When the ignition switch is turned OFF, then after the traction motor stops, the self shut-OFF relay turns OFF
and the hybrid system stops.
CONDITIONS FOR MOTOR DRIVING
When all of the conditions below are met, HPCM stops the engine and transitions to motor driving.
*: Even if there is a malfunction in the hybrid system, in some cases the fail-safe function may allow motor driving.
NOTE:
When the select lever is in the P position the driver seatbelt is unbuckled, and the driver seat door is opened, the engine starts.
CLUTCH FUNCTION
Clutch 1 Function
- Clutch 1 is installed between the engine and traction motor.
- When the engine is running and engine output torque is transmitted to the transmission, the clutch is engaged.
- During motor driving, the clutch is disengaged in order to reduce the load on the traction motor.
For the clutch structure and operation, Description and Operation.
Clutch 2 Function
- Clutch 2 is a component inside the transmission. It is used for engine start, starting from a stop, and shifting speeds.
For the clutch structure and operation, Cross-Sectional View.
- For engine start, starting from a stop, and changing speeds, clutch 2 is allowed to slip, controlling the drive force that is transmitted to the drive wheels and providing smooth driving.
SYSTEM DISPLAY FUNCTION
HPCM controls the information display on the combination meter and the navigation monitor based on the signals from the sensors and control modules in order to inform the driver of the vehicle conditions.
Energy Monitor
- The operating status of each system can be checked by displaying the energy monitor on the navigation display or on the information display in the combination meter.
- HPCM transmits the status of each system to the AV control unit and combination meter via CAN communication. When the AV control unit and combination meter receive the signals, the energy monitor and fuel economy history are each displayed on the navigation display and information display.
For the displayed screen, Base Audio.
Li-ion Battery State of Charge
- The level of the Li-ion battery can be checked by displaying the Li-ion battery state of charge on the information display in the combination meter.
- HPCM receives the Li-ion battery level from the Li-ion battery controller via CAN communication, and transmits the Li-ion battery state of charge signal to the combination meter via CAN communication. When the combination meter receives the signal, it displays the value indicated by the HPCM on the Li-ion battery state of charge.
Assist Charge Gauge
- The operating status of the traction motor inverter can be checked from the assist charge gauge located in the combination meter.
- HCPM transmits the assist charge signal to the combination meter via CAN communication. When the combination meter receives the signal, it activates the assist charge display and displays the traction motor status.