Civic Hybrid: IMA Electric Motor
Providing supplemental power boost to the 1.3-liter 4-cylinder engine and giving the Civic Hybrid the capability to cruise on its electric motor in certain cruising situations, the IMA's electric motor is designed to provide up to 20 horsepower (15 kW) and 66 lb-ft. of additional torque to the Civic Hybrid's engine. Mounted between the engine and the CVT transmission, the IMA motor is an ultra-thin (70 mm) DC brushless design and provides a substantial amount of low-end torque to aid acceleration, while also assisting in steady-state cruising and hill climbing.

In addition to providing supplemental motive power, the IMA motor acts as a generator during deceleration and braking to recapture kinetic energy and recharge the IMA's battery pack during regenerative braking. For this fourth generation of IMA motor, a new internal permanent magnet was designed to increase output density and make the motor more efficient than previous motors. It also uses flat wire construction to increase wire density. The electric motor has increased output horsepower by 50 percent and maximum torque by 14 percent compared with the 2005 Civic Hybrid IMA motor. The electric motor is also more efficient, now converting 96 percent (versus 94.6 percent efficiency of the 2005 Civic Hybrid IMA motor) of the available electricity into motive energy in assist mode.

Civic Hybrid: IMA Intelligent Power Unit (IPU)
Power for the IMA system is controlled through the Civic Hybrid's Intelligent Power Unit. Located directly behind the rear seatback, the IPU consists of the Power Control Unit (PCU) – or the IMA's command center, a rechargeable Nickel Metal-Hydride battery module, and an integrated cooling unit.

The Power Control Unit (PCU) electronically controls the flow of energy to and from the IMA's electric motor. Using the latest in computer chip technology, the PCU's response time is quickened over previous versions, and a new inverter and DC/DC Converter help contribute to the IMA's overall increase in peak power.

The battery pack stores electricity in a bank of Nickel Metal-Hydride cells. This bank of 132 1.2-volt units stores up to 158 volts of electrical energy for the IMA motor compared to 144 in previous versions. A new Panasonic® dual module casing reduces weight from previous hybrid battery packs and also allows it to increase efficiency of the electrical flow. The 12 percent smaller volume of the battery pack accommodates more cargo space.

The Integrated Cooling Unit offsets the heat generated by the constant flow of electricity to and from the battery pack with an integrated cooling system mounted directly on the battery pack's outer box. Interior cabin air is continually flowed over the battery pack and re-circulated via a small vent placed on the rear seat shelf.

Source: Honda PR