Volvo tests various range extender concepts for e-cars

July 15, 2011 // By Christoph Hammerschmidt
Volvo is taking the next step in the company's electrification strategy by producing test cars with range extenders - electric cars that are fitted with a combustion engine to increase their effective range. The projects encompass three potential technology combinations. Tests will get under way in the first quarter of 2012.

The company regards range extenders as the best way to overcome the range limits of electric vehicles operating solely on battery power. Derek Crabb, Volvo's Vice President Powertrain Engineering, said he expects that the additional combustion engines could extend the driving range to more than 1000 kilometers - operated on battery power alone, the driving range of e-cars typically does not exceed the 200 km mark.

Volvo's technological developments in this area currently encompass three different technology combinations, with three-cylinder petrol engines being installed to complement electric drive to the front wheels. All the variants feature brake energy regeneration. The engines can run on both petrol and ethanol (E85).

Two of the solutions are based on the Volvo C30 Electric. In both cases, the standard battery pack has been somewhat reduced in size to make room for the combustion engine and its fuel tank.

Concept I is based on a C30 Electric with a three-cylinder combustion engine producing 60 horsepower (45 kW) installed under the rear load compartment floor. The car also has a 40 litre fuel tank.

The combustion engine is connected to a 40 kW generator. The power it generates is used primarily to drive the car's 111 horsepower (82 kW) electric motor, but the driver can also choose to let the generator charge the battery, thus increasing the car's operating range on electricity.

The range extender increases the electric car's range by up to 1,000 km - on top of the 110 km range provided by the car's battery pack.

In concept II, the car gets a more powerful three-cylinder combustion engine at the rear and a 40 litre fuel tank. The difference between this and the first solution is the parallel connection, whereby the turbocharged 190 horsepower engine primarily drives the rear wheels via an automatic transmission. This gives a better fuel efficiency rating when driving with the combustion engine cruising on the highway. A 40kW