Thursday, November 13, 2008

Chevrolet volt,the plug-in concept electric car

The Chevrolet Volt is a plug-in series hybrid vehicle to be produced by General Motors,and expected to be launched as a 2011 model with production currently slated to begin in Q:3 2010.The Volt's propulsion system will be based on GM's new E-Flex platform.

Since the definition of a "hybrid vehicle" as outlined by the Society of Automotive Engineers includes only vehicles having "two or more energy sources directly providing propulsion, either individually or shared" the company has avoided the use of the term "hybrid" when describing the Volt- preferring to call it an electric vehicle equipped with a "range extending" gasoline powered internal combustion engine (ICE) as a genset and therefore dubbed an "Extended Range Electric Vehicle" or EREV. However the combination of an internal combustion engine and electric motors in such a configuration is most often referred to as a series hybrid.
Unlike conventional hybrids, the Volt is designed to operate its propulsion system entirely on electric power. Assuming a full-charge, this electric power will initially be sourced exclusively from its on-board Lithium Ion batteries for up to 40 miles (64 km), a distance capable of satisfying the daily commute of 75% of Americans, which averages around 33 miles (53 km).
After 40 miles, the range of the Volt will need to be extended through the use of a small 3-cyl internal combustion engine which drives a 53kW generator. This arrangement creates a sustaining charge current to the HV batteries and permits them to continue powering the 111kW electric drive motor. This effectively extends the Volt's potential range to as much as 640 miles (1,030 km) on a single tank of fuel. (and which could be potentially extended for longer trips through conventional refueling).
The Volt's 16kWhr Lithium-Ion battery pack can also be fully charged (technically ~85% SOC) by plugging the car into a 120-240VAC residential electrical outlet using the provided SAE J1772 compliant charging cord. No external charging station will be required.

The Volt concept vehicle had four doors with a rear liftgate, and it is capable of carrying four passengers. This is a significant change in design philosophy when compared to the General Motors’ EV1 of the 1990s, which only seated two. The top speed has also been increased on the Volt, from 80 miles per hour (130 km/h) to 120 miles per hour (190 km/h). The battery pack size has also been reduced, from about 300 L in volume in the EV1, to just 100 L in the Volt. The weight of the battery pack in the Volt will also be significantly less (reportedly ~375lbs) , primarily because the Volt will use lithium-ion batteries while the EV1 used heavier lead-acid and nickel metal hydride batteries.

GM executives report that battery technology will have a large impact in determining the success of the car.

To help spur battery research, GM selected two companies to provide advanced lithium-ion batterypacks: Compact Power, which uses manganese oxide based cells made by its parent company, LG Chemical, and Continental Automotive Systems, which uses nanophosphate based cylindrical cells made by A123Systems. However, on August 9, 2007, GM established a more close-knit relationship with A123Systems so that the two companies could co-develop a Volt-specific battery cell. This cell was later unveiled at the EVS23 industry convention in Anaheim, CA. Work with CPI has continued at a rapid pace, and in late 2007 CPI delivered two fully-functional prototype battery packs to GM's testing facilities. On January 31, 2008, A123 and Continental delivered their first prototype to GM's European test facilities. GM will likely use both suppliers for the Volt, although this remains a matter of speculation.

GM expects ten years of life out of the batteries. As of early 2008, they had started extensive battery testing and planned to have 10-year battery results in two years. Batteries were placed in Chevrolet Malibus for further real-world testing.
In February 2008, Andrew Farah, the car's chief engineer, said that design and production was ten weeks behind the original schedule, and that further slippage would mean that the 2010 deadline could not be met.
In April 2008, GM Vice Chairman Bob Lutz said that the first battery test mule was now running with a lithium battery pack.
In July 2008, GM confirmed that a non-turbocharged, 1.4 liter 4-cylinder engine will be used as the range extender, and that the intention is to build it in Flint Michigan.
In August 2008, Andrew Farah, the car's chief engineer, said that the 10 week delay mentioned in February had been "erased" as work on mechanical parts took place during that time. Farah further states the project remains on-track to hit the 2010 deadline saying "at this point, there’s nothing standing in our way of continuing to do what we said we’re going to do."
In early September 2008 Autoblog reports and posts potentially "leaked" photos of the production version of the Chevrolet Volt along with various members of its development team found their way onto the Net Significant changes from the original design concept is met with mixed reviews.
On Sept 16 2008 General Motors officially revealed the production version of the Volt.
Also in September 2008, Bob Lutz indicated on an episode of the Colbert Report that they will offer an optional thermovoltaic solar power roof, allowing the owner to charge the battery by leaving the vehicle in sunlight.
As of August 2008, General Motors Chairman and Chief Executive Officer Rick Wagoner was quoted saying that the price of the Volt in the U.S. market would likely be in "the mid to high 30's." Initially, the GM vice president wanted it at about US$30,000.

The indicated price for the UK market is GBP20,000.

For trips less than about 40 miles (64 km) per charging cycle, the Volt will not use any onboard gas, so assigning a fuel consumption value which only referred to onboard fuel might not be appropriate. Once the Volt's battery has discharged to its lower limit set-point, the Volt's range-extending gasoline engine is expected to get from approximately 50 mpg-US (4.7 L/100 km) to as much as 150 mpg-US (1.6 L/100 km) depending on its "run-time" duty cycles. This is because once the battery has been recharged to an upper limit set-point (by the engine driven 53kW onboard generator), the internal combustion engine will again shut off.Therefore the variables that contribute to the specific duty cycle periods of the internal combustion engine run-times, will need to be factored in to the Volt's final fuel economy rating as determined by the EPA.