AT the heart of the Insight's hybrid system is an ultra-thin (60mm) 10kW permanent-magnet electric motor mounted between the engine and transmission and providing additional power assistance under certain conditions. During acceleration, power to the front wheels is supplied jointly by the petrol/electric motor the petrol engine does the work during cruising, while deceleration and braking enables the electric motor to act as a generator and recharge the battery pack. The IMA system also has an "Auto Stop" feature, which shuts off the petrol engine at idle to save fuel and minimise emissions. The pack of 120 D-sized nickel-metal hydride batteries (total voltage 144V, amp-hours 6.6) is stored at the rear of the vehicle.