DESCRIPTION
The HCU (Hybrid Control Unit) controls whole hybrid systems and is connected with each control modules (ECM, TCM, MCU, BMS ECU etc.) by CAN interface. In addition this system uses the brake switch and Clutch Pressure Sensor (CPS) signals for controlling the hybrid system.
Note. CAN interface is divided into hybrid and chassis CAN lines.
Scheme 15
The HCU controls power & torque distribution of the engine and motor, regenerative brake, and fail-safe mode based on the vehicle information, driver's demand, engine information and high voltage battery information.
Scheme 16
[HCU Main Functionalities]
| Item | Functionality |
|---|---|
| Demand Torque Determination | Driver Creep Demand Torque Calculation Driver Acceleration/Deceleration Torque Calculation Driver Total Demand Torque Calculation |
| Regeneration Brake Control | Regeneration Brake Demand Torque Control Regeneration Brake Estimated Torque Calculation |
| EV/HEV Mode Determination | Engine Crank Condition Determination Engine Target Operating Status Determination |
| Battery SOC Balancing | Electric Power Limitation Charge/Discharge Power Determination Auxiliary System Power Limitation and Compensation |
| Engine Operating Point Determination | Engine Target Speed Determination in Idle Load Engine Target Torque Determination in Part Load Engine Target Torque Determination in Full Load Engine Target Torque Determination in Engine Stop or Passive Run |
| Idle/Racing Charge Control | Idle Charge Control Racing Charge Control |
| Engine Start/Stop Control | Crank Method Selection Speed Control for Cranking Engine Fuel Injection Control Engine Stop Control Engine Firing Complete Determination |
| Engine Clutch Engage/Slip/Release Control | Synch Engage Control Launch Engage Control Engine Brake Engage Control Engage in Shift Release Control |
| Torque Coordination Control | Engine Torque Determination in Transient State Motor Torque Determination in Transient State Generator Torque Determination in Transient State |
| Torque Invention Control | Torque Increase/Decrease Determination |
| Anti-Shock Control | Parabolic Torque Restriction Shift Assist Control Engine Clutch Slip Control Anti-jerk Control |
| System Limit Control | Battery Charge/Discharge Limit Control Engine, Hybrid Drive Motor, HSG Torque Limit Control |
| Torque Monitoring | Hybrid powertrain torque monitoring |
| Fail-Safe | Hybrid control system fail-safe control |
| Auxiliary System Control | Electric Oil Pump Control Variable Voltage Control of Low Voltage DC/DC A/C & Heater Control Brake Boost Control Cluster Display |
HCU MAIN FUNCTIONALITIES
The Hybrid Power Control Unit (HPCU) is an integrated power conversion unit which consists of the two inverters, LDC, and HCU.
Scheme 17
The Brake Switch is installed on the brake pedal and linked with the HCU and stop lamp. It sensors the status of the brake pedal (Release, Push) and transmits the signal to the HCU.
Scheme 18
The engine clutch is installed inside the hybrid drive motor assembly and operated by hydraulic pressure. It mechanically connects or disconnects the engine drive power to the transaxle and its oil pressure is sensed by the Clutch Pressure Sensor (CPS). The HCU can recognize the vehicle driving mode (EV Mode, HEV Mode) by using this signal. This sensor is located beside the electric oil pump in the transaxle housing.
