An Investigation of Fuel Economy Potential of Four 1977-Model Vehicles

A vehicle testing program was conducted to determine the inherent fuel economy potential of current (1977) technology engines given freedom to optimize engine adjustment for best fuel economy with no constraint on engine-out emissions. The average city/highway fuel economy of four car models with optimized air-fuel ratio and spark timing was improved by 4.1% as compared to the fuel economy of the baseline values found for the vehicles with air-fuel ratio and spark timing at manufacturer's specifications.