Volvo’s Flywheel KERS (Kinetic Energy Recovery System) hybrid system was the first of many gas-electric experiments for the Scandinavian automaker. Now the focus is on range extenders for electric vehicles. Volvo is working on three different combinations of gas engines and electric motors which it claims can push the electric car’s at least 620 miles (1000 km) further than on battery power alone. All three versions use three-cylinder engines that can run on gasoline or E85 combined with electric generators and motors.
The first two systems are based on the Volvo C30 Electric and the third is based on the V60 wagon. Both systems for the C30 necessitate a smaller battery pack to fit the internal combustion engine installed under the rear load compartment floor and its 10.5 gallon (40 liter) fuel tank. All three systems feature brake energy regeneration.
The first C30 Electric-based concept uses a series-connected range extender which utilizes a naturally-aspirated 60-hp three-cylinder engine. The I-3 is connected to a 40 kW generator which drives the car’s 111-hp (82 kW) electric motor. The system offers a driver selectable option to let the generator charge the battery pack, increasing the car’s operating range on electric power alone. Volvo claims this range extender increases the electric car’s range by as much as 620 miles (1000 km) over the 69-mile (110 km) range of the battery pack.
The second C30 Electric range extender system is parallel-connected; this concept uses a turbocharged 190-hp three-cylinder engine hooked to a six-speed automatic which drives the rear wheels. Volvo claims this system gives better fuel efficiency when cruising on the highway with the internal combustion engine. This system also hooks a 40kW generator to the gas/E85 engine to charge the battery pack which provides power to the 111-hp (82kW) electric motor connected to the front wheels. Volvo claims the combined rating of the engine and motor total 301-hp which helps the C30 Electric reach 62 mph (100 km/h) in less than six seconds. This range extender increases the car’s range by more than 620 miles (1000 km) past the 46.5-mile (75 km) range.
The Volvo V60 concept also uses a parallel-connected range extender similar to the aforementioned C30, but in this application the entire drive package installed under the hood. It uses the same turbocharged 190-hp three-cylinder engine, 40kW generator and 111-hp (80 kW) electric motor as the C30 Electric parallel system. The car can travel up to 31 mph (50 km/h) on electric power alone. Once the car exceeds 31 mph power from the force-inducted three-banger powers the front wheels through a two-stage automatic transmission. The gas engine also recharges the battery pack when its charge drops below a predetermined level. The battery pack located under the rear load floor can give the car a range of 31 miles (50 km) on electric power alone. Volvo claims the V60’s total range exceeds 620 miles (1000 km) and is fitted with an 11.9 gallon (45 liter) fuel tank.
"This is an exciting expansion of our increasing focus on electrification,” said Derek Crabb, Vice President of Powertrain Engineering, Volvo Car Corporation. "Battery cost and size mean that all-electric cars still have a relatively limited operating range. With the Range Extender, the electric car has its effective range increased by a thousand kilometers - yet with carbon dioxide emissions below or way below 50 g/km."
The series-hybrid range extender in the C30 is part of an EU project of eight partners -- Volvo being the only automaker in the group. The two parallel-hybrid range extenders are being developed with a grant of nearly $1.7 million (EUR 1.2 million) from the Swedish Energy Agency.