Always Driven by an Electric Drive Unit: The New Opel Ampera

By dancurranjr On March 8th, 2009

opel-amperaThe Opel Ampera is an emission-free, electrically propelled automobile that runs on electricity stored in the 16 kWh lithium-ion battery up to 60 kilometres. When the battery’s energy is depleted, electricity from an on-board engine-generator extends the five-door, four-seat hatchback’s range to more than 500 kilometres. The battery of the Voltec motor can be charged at any household 230-volts power outlet. The new model, which derives from the Chevrolet Volt, debuts at the Geneva Motor Show. Additionally, the electric car will be offered with right-hand drive in the United Kingdom by Opel’s sister-brand, Vauxhall.

The Ampera’s battery pack will be manufactured by General Motors (GM) at the first lithium-ion production facility to be operated by a major automaker in the United States. More than 220 lithium-ion cells in the T-shaped pack provide ample power. The nearly silent electric drive unit delivers 370 Newton metres of instant torque, from standstill to 100 kilometres per hour acceleration in around nine seconds, and a top speed of 161 kilometres per hour.

Voltec is the brand name for GM’s Extended-Range Electric Vehicle (E-REV) technology that uses electricity as its primary power source and gasoline as its secondary power source to generate electricity. The main components of the Voltec electric propulsion system include a T-shaped battery pack, an 111 kilowatts electric drive unit, and an engine generator of electricity. Energy is stored on board in a 16 kilowatt-hours, T-shaped lithium-ion battery pack. The battery pack powers the electric drive unit, which is capable of meeting full vehicle speed and acceleration performance while driving the car electrically for up to 60 kilometres (MVEG cycle) without using a drop of gas. For longer trips, the E-REV’s on-board range-extending engine is used to drive an electric generator when the battery’s energy has been depleted.

Opel estimates that an electrically driven kilometre in the Ampera will cost about one-fifth compared to a conventional gasoline vehicle, at current fuel prices. According to the company, GM Europe is analysing the requirements of a recharging infrastructure for plug-in electric cars with energy companies, including Iberdrola of Spain.

While driving on electricity delivered by the battery, the Ampera emits zero CO2. When the battery’s energy is depleted, a gasoline/E85-fueled engine-generator seamlessly provides electricity to power the electric drive unit while simultaneously sustaining the charge of the battery. This mode of operation extends the range to 500 kilometres, until the battery can be charged by plugging the vehicle’s on-board charge system into a standard household 230-volts outlet.

The Ampera represents a departure from conventional hybrids. In practice, hybrid vehicles typically require both sources – engine and battery – to provide full vehicle performance capability. In a hybrid vehicle, the combustion engine is typically the larger of the two propulsion sources, and provides most of the power during high power vehicle manoeuvres like off-line starts and freeway cruising. A plug-in hybrid operates the same way, but can be recharged by plugging in. Even with useful energy in the battery, the engine will often be operating to achieve vehicle peak loads. An E-REV is unique from a hybrid or plug-in hybrid in that the vehicle’s wheels are always driven electrically by an electric drive unit.

The vehicle, whose exterior design takes up cues from the Opel Flextreme and GTC Concept show cars, will go into production in late 2011.


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