SEVERAL POSSIBLE PATHS TO IMPROVED PART-LOAD ECONOMY OF SPARK-IGNITION ENGINES

Due to the many losses in the conversion of heat to mechanical energy a gallon of fuel provides less than 1/4 of its mechanical equivalent of useable energy at the flywheel. These losses are described and an attempt is made at cataloguing them and appraising their magnitude at one speed and road load corresponding to the speed and road load of a compact car operating at 40 miles per hour on a level road. Some areas where improvements in efficiency may be obtainable through future research and development are discussed. A speculative estimate is made as to possible future efficiency increases based on this study.