Consumer and Manufacturer Design Factors for Use of Compressed Natural Gas (CNG) in American Automobiles

Despite significant research and development during the past quarter century, there has been an insignificant transition to use of compressed natural gas (CNG) vehicles. Although CNG automobiles reduce harmful emissions and reduce consumption of foreign oil, the nation has not successfully transitioned away from gasoline and diesel fuels. Therefore, the pros and cons of owning and operating CNG vehicles are explored from the consumer’s perspective. Included in this paper are isentropic compression models for single stage, 4 stage isentropic, and 4 stage with a constant temperature increase between cylinders. The models are then used to predict charging times for both residential and industrial compressors for an energy basis of 1MMBtu (1.055 GJ). The impact of CNG vehicles on US air emissions is discussed, with qualitative comparisons of CNG and oil-based emissions.Copyright © 2009 by ASME