What Is An E-REV?

This article is from a General Motors Media site.  For more information about the Chevrolet Volt, visit

http://media.gm.com/volt

WHAT IS AN E-REV?

The 2011 Chevrolet Volt is a front-wheel-drive, four-passenger Extended-Range Electric Vehicle (E-REV) that uses electricity as its primary power source and gasoline as its secondary power source to propel the vehicle. 

An E-REV like the Chevrolet Volt represents a significant departure from conventional hybrids. In a E-REV, the wheels are turned by an electric drive unit, whereas in conventional hybrids the wheels are turned by an electric motor, a gasoline engine, or both.  For short trips, E-REVs will run on battery power alone. For longer trips, additional electricity can be supplied by an internal combustion engine or a fuel cell. The battery and propulsion systems are sized so that when sufficient energy is available from the battery, the engine (or fuel cell) is not required for operation.  During this electric only phase of driving, the battery, motor, and power electronics are designed to deliver full performance, acceleration, top speed, hill climbing on electric power alone.

HOW VOLT WORKS:
Energy is stored on board in a 16-kWh, “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 40 miles (64 km) (based on EPA city cycle) without using a drop of gas. For longer trips, the Volt’s on-board range-extending engine is used to drive an electric generator when the battery’s energy has been depleted. The range extender, which can be powered by gas/E85 Ethanol, is able to generate additional electricity to power the car for hundreds of miles.

A new and distinct propulsion system category that would comprehend E-REVs has been proposed by the California Air Resources Board, which GM expects that the Chevrolet Volt will become the first to qualify.  Other government agencies are also considering the unique benefits of E-REVs.

BENEFITS:
There are many benefits of an E-REV like the Chevrolet Volt. The main benefits include energy diversification, reduced oil consumption, and reduced emissions.

According to a Society of Automotive Engineers study published by GM in April 2008, an E-REV will consume, on average, less than half of the gasoline compared to a plug-in hybrid and substantially reduce regulated emissions resulting from initial trip starts. According to a 2003 Omnibus Household survey by the U.S. Department of Transportation, nearly 80 percent (76 percent) of U.S. drivers commute 40 miles or less daily. 

GM estimates that the Chevy Volt will save about 500 gallons (1,892 liters) of gasoline based on 40 miles of daily driving and 15,000 miles annually. For drivers that commute 60 miles (96 km) per day or 21,000 miles annually, about 550 gallons (2,081 liters) of gasoline could be saved.

As a baseline comparison, GM estimates that the cost per mile to operate an E-REV like the Chevy Volt is approximately two cents per mile electrically versus 12 cents per mile using gasoline priced at $3.60 per gallon.

NOT A “HYBRID”:
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 maneuvers 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 like the Chevrolet Volt is unique from a hybrid or plug-in hybrid in that the vehicle’s wheels are always driven electrically by an electric drive unit.

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2011 Chevrolet Volt Propulsion System Image

Jeremy Lloyd – Jay the Car Guy

Bancroft Motors LTD

http://www.bancroftmotors.ca

j.lloyd@bancroftmotors.ca

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General Motors – Research and Development – Milestones

GM R&D has a long history of innovation.

2000s: First automotive use of nanocomposite materials; industry first quick-plastic-formed aluminum panels; VehSim virtual chassis/driveline controls simulation; first virtual crash laboratory; SIMTHRU manufacturing throughput simulation; industry first vehicle-to-vehicle communications system demonstration; six-speed transmissions; industry first FEA-compatible front crash sensing algorithm; FlexFuel and hybrid vehicle technologies; AUTOnomy, Hy-wire, and Sequel fuel cell/by-wire concept vehicles; electric wheel-hub motors; high-power density fuel cell stack and propulsion system; E-Flex flexible electric drive system.

1990s: StabiliTrak electronic stability control system; magneto-rheological fluid-controlled suspension; EV1 electric vehicle; OnStar safety & security service; industry’s first virtual design environment.

1980s: Magnequench rare-earth magnets; first engine oil-change indicator.

1970s: First catalytic converter; first production airbag; first computer crash simulation.

1960s: Energy-absorbing steering column; electric and fuel cell vehicle concepts.

1950s: America’s first turbine-powered car; first computer operating system;
GMR-Dodrill mechanical heart, first such device successfully used during surgery.

1940s: First high-compression internal combustion engines.

1930s: First non-flammable, low-pressure refrigerants, which made vehicle and home refrigeration practical.

1920s: First anti-knock gasoline additives, which led to high-performance fuels.