The piston of the free-piston internal combustion engine pumps hydraulic fluid into the accumulator. It stores the energy by compressing the gas bladder inside. The engine will be turned off automatically when the accumulator is filled – and turned on again automatically shortly before it becomes empty.

The pressurized fluid drives the wheelmotors, one in each wheel. Their driving power is continuously variable from zero to maximum speed.

The wheelmotors are reversed during braking and become pumps. They are powerful enough to stop the car like disk brakes, while recuperating the entire braking energy. The energy is stored in the accumulator and used again for driving. The ‘round-trip-efficiency’ during braking is 70% to 85%. The energy is stored in the accumulator and will be used again to drive the car.

The powertrain computer controls the functioning of the engine and the wheelmotors. It also manages the state of charge of the accumulators for driving and braking.

The wheel is driving the car.

The wheel is driven by the energy from the accumulator.

The engine charges the accumulator with pressurized fluid

Animation of the engine.

The car has four wheels. All wheels have a wheelmotor.

Animation of the INGOCAR.