IMA System The IMA (integrated motor assisted) system is a highly-efficient parallel hybrid drive system consisting of a main power unit (gasoline-fueled engine) and the assist unit (electric IMA motor).The engine is an in-line 4-cylinder 8-valve power plant that has a displacement of 1.339 liters. To reduce fuel consumption, the engine is equipped with I-DSI and a valve pause system that reduces engine pumping loss and increases the regeneration of electric energy during deceleration. The IMA motor, directly connected to the engine crankshaft, functions as a generator during deceleration, an engine starter, and a motor to assist the engine that drives the wheels.The IMA system contains the 100 V (approx.) DC battery, control system, and related accessories. For safety, the intelligent power unit (IPU) is located under the trunk compartment. The IMA system can reduce fuel consumption by regenerating energy during deceleration that is not usually used to electric energy. Also, the assist of motor increases output by about 10 %. IMA Operating Condition 1Engine start: The IMA system drives the IMA motor and starts the engine during normal starts and when re-starting from an idle stop. The IMA motor is linked directly to the engine crankshaft, providing quieter and smoother starts than a starter.2Start running (Engine Operation and Motor Assist): The IMA motor assists running with the engine.3Slow acceleration (Engine-only Operation): Running with engine only.4Low speed Cruise (Motor-only Operation): When running at a constant speed of about 40 km/h (25 mph), all engine cylinders are deactivated and running is performed by motor only.5Acceleration (Engine Operation and Motor Assist): The IMA motor assists running with the engine.6High Acceleration (Engine Operation and Motor Assist): The IMA motor assists running with the engine.7High speed Cruise (Engine-only Operation): Running with engine only. When the state of charge (SOC) drops, the IMA motor begin to charge the battery module.8Deceleration (Battery module Charging): All engine cylinders are deactivated and the IMA motor regenerates deceleration energy and charges the battery module.9Stop (Auto Idle Stop): When conditions are satisfied, the PCM stops the engine automatically. When the battery module charge is at or above the specified value When the SOC* of the battery module is at or above the specified value, regeneration volume is restricted to prevent overcharging. Since regenerative braking force is insufficient at this time, the PCM cancels full cylinder deactivation and increases engine braking power. When the battery module charge is at or below the specified value When the SOC* of the battery module drops, idle speed is increased in accordance with each shift position and the battery module state of charge in order to charge the battery module. When the battery module SOC* value is drops, selecting the L range mode triggers charge priority control to give priority to battery module charging by lowering the IMA motor assist level, increasing the idle speed, and increasing the regeneration volume . Charge priority control is cancelled when the battery module state of charge reaches about 40% or greater, which returns control to the normal L range mode and changes the idle speed to 750 min －1 (RPM). 5 position SOC of Battery module (%)less than 30%about 30－39%more than 40%positionP or N1200 min －1 (rpm)750 min －1 (rpm)750 min －1 (rpm)D, S, R1100 min －1 (rpm)750 min －1 (rpm)750 min －1 (rpm)L1100 min －1 (rpm)1100 min －1 (rpm)750 min －1 (rpm)6 position SOC of Battery module (%)less than 30%about 30－39%more than 40%positionP or N1200 min －1 (rpm)750 min －1 (rpm)750 min －1 (rpm)D, S, R1100 min －1 (rpm)750 min －1 (rpm)750 min －1 (rpm)S－L mode1100 min －1 (rpm)1100 min －1 (rpm)750 min －1 (rpm) When the engine cannot be started with the Based on signals from the MCM when the SOC* value drops, when temperature is low, or when there is trouble with the IMA system, the PCM judges that the engine cannot be started by the IMA motor and so engine starting is performed by the starter. SOC* State of Charge IMA Electric Motor The IMA motor is a synchronous AC type that converts electrical energy into kinetic energy and vice versa. It assists the engine during acceleration, runs the vehicle itself during low speed cruise, and starts the engine.The motor is located between the engine and the transmission. It consists of a 3-phase coil stator and a permanent magnet rotor that is directly connected to the engine crankshaft. A IMA motor rotor position sensor is mounted on the back of the engine block to detect the position of the rotor. The IMA motor is reduced in thickness and weight compared to the previous model.