July 29, 2011
The development of fuel efficient cars was primarily in response to the OPEC oil
crisis of the nineteen-seventies and the dramatic rise in gasoline prices for American
motorists. Centuries ago, Americans drove gas guzzling cars. The price of gasoline was cheap and consumers were not interested in purchasing fuel efficient cars, so automakers did not produce fuel efficient cars. But today gas prices have skyrocketed; fuel efficient cars have become a necessity.
New concerns about the threat of global warming, the shortage of crude oil, and the stringent emission standard stimulate automobile manufactures to provide customers with fuel saving, environment-friendly, and affordable vehicles without sacrificing performance, safety, and reliability. Hybrid electric vehicles combined with more than one power source are assumed to be one of the most promising alternatives to engine only vehicles (Qiang, Zhong, Mao, Yang, Zhuo, 2007).
Hybrid electric vehicles combined with more than one power source offer additional flexibility to improve the fuel economy and to reduce pollutant emissions. The dynamic programming based supervisory presented here investigates the fuel-economy improvement and emissions of nitrogen oxides for a state of charge sustaining parallel HEV (Dave, 2009).