Volvo developing extended-range electric vehicle concepts with three different technology combinations

Volvo is taking the next step in its electrification strategy by producing test electric vehicles with range extenders. Supported by the Swedish Energy Agency and the EU, the project comprises three potential technology combinations: one a series-hybrid range extender configuration; and two parallel-hybrid range extender configurations. Tests of the concepts will get under way in the first quarter of 2012.

The concepts all use three-cylinder flex fuel (gasoline and E85) engines to complement the front-wheel electric drive. 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.

This is an exciting expansion of our increasing focus on electrification. 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.

—Derek Crabb, Vice President Powertrain Engineering at the Volvo Car Corporation

Technical concept I. Click to enlarge.

Technical concept I: Volvo C30 with series-connected range extender. This is based on a C30 Electric with a three-cylinder combustion engine producing 60 hp (45 kW) installed under the rear load compartment floor. The car also has a 40 liter 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 hp (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 (621 miles),on top of the 110 km (68-mile) range provided by the car’s battery pack.

Technical concept II. Click to enlarge.

Technical concept II: Volvo C30 with parallel-connected range extender. In this implementation, the car gets a more powerful three-cylinder combustion engine at the rear and a 40 liter 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 a six-speed automatic transmission.

This gives a better fuel efficiency rating when driving with the combustion engine cruising on the highway. Via a 40 kW generator the battery can also be charged to give the car increased range on electricity alone.

Here too the electric motor is a 111 hp (82 kW) unit. The two power sources give the car more than 300 hp in total, and acceleration from 0-100 km/h of less than six seconds.

The range extender increases the electric car’s range by more than 1,000 km in addition to the range of up to 75 km (47 miles) provided by the car’s battery pack.

Technical concept III. Click to enlarge.

Technical concept III: Volvo V60 with parallel-connected range extender. This is a solution whereby the entire drive package is installed under the hood at the front. The 111 hp (80 kW) electric motor is supplemented with a three-cylinder turbo engine producing 190 hp (140 kW), a two-stage automatic transmission and a 40 kW generator. Power from the combustion engine drives the front wheels via the gearbox and recharges the battery pack whenever needed.

Up to 50 km/h (31 mph), the car is always powered solely by electricity. The combustion engine is activated at higher speeds and charges the battery pack when its charge drops below a predetermined level.

The battery pack is located under the rear load floor and it gives the driver a range of 50 km on electricity alone. The car also has a 45 liter tank.

The range extender increases the car’s total range by more than 1,000 kilometers.

The series-hybrid range extender in the C30 is part of an EU project in which the Volvo Car Corporation is the only car manufacturer among eight partners. The company’s two parallel-hybrid range extender solutions are being developed with a grant of SEK 10.8 million (US$ 1.7 million) from the Swedish Energy Agency.

Source: Green Car Congress