FUSO 4M4 – HYBRID ELECTRIC VEHICLE SYSTEM – STRUCTURE AND OPERATION – Outline

1.1 Hybrid electric vehicle system

• Respective electronic control units, which constantly send and receive input and output data through controller area network communication, take their shares of control to ensure the normal operation of the hybrid electric vehicle system.

1.2 Driving
•The engine and motor generator are operated, independently or combined, by the torque (drive force) distribution command of the INOMAT-II electronic control unit in accordance with the vehicle running condition and high voltage battery state of charge.

(1) When starting
• The motor generator is used to start the vehicle.

(2) When running (high voltage battery state of charge: Normal)
• With the clutch engaged, the vehicle runs using the engine only.

(3) When running (high voltage battery state of charge: High)
• The engine is assisted by the motor generator.

(4) When running (high voltage battery state of charge: Low)
• The motor generator is operated as a dynamo by the engine.

(5) When running (during gear shifting)
• The motor generator is used to facilitate the synchronized gear shifting.

(6) When braking
• The motor generator is operated as a dynamo to charge the high voltage battery with braking energy regenerated. At the same time, braking force equal to that of engine brake is generated.
• When large braking force is required, engine or exhaust braking is activated with the clutch engaged.

1.3 Motor generator and drive line

• The motor generator is located in the back of the clutch housing.
• By the command of the motor electronic control unit, direct current high voltage output from the high voltage battery is converted to a three-phase alternating current through the inverter and flows into the stator assembly to produce a magnetic field in it. As a result, the rotor is turned to send the torque (drive force) to the transmission.
• During braking, the motor generator operates as a dynamo. The rotor is turned to produce three-phase alternating current in the stator assembly. Three-phase alternating current is converted to direct current high voltage through the inverter to charge the high voltage battery.
• The smoothing capacitor in the motor electronic control unit stabilizes direct current high voltage.

(1) Drive line (when motor generator operates alone)
• The engine is in the idling state with the clutch disengaged.
• The motor generator operation drives the drive pinion to run the vehicle.
* The illustration at the left outlines the structure and operation of the drive line. For the actual clutch-related operation, see Gr21.

(2) Drive line (when engine operates alone)
• The clutch is engaged and engine output torque (drive force) is directly transmitted to the drive pinion.

(3) Drive line (when engine and motor generator operate)
• The clutch is engaged and engine output torque (drive force) is transmitted to the drive pinion along with motor generator output torque (drive force).

1.4 High voltage battery box

1.5 High voltage cooling system