THIS paper reviews the experience of one company over a period of years in developing its product to give better fuel economy in spite of the demand for increased performance and the rising trend of car weight which has been occasioned by advance styling and appearance items.
The data presented indicate how air-fuel ratios have been improved and compression ratios increased over a period of years, and some of the other factors influencing fuel economy. The effects of compression-ratio increase are discussed along with the use of higher-octane fuel and the necessity of proper choice of performance factors to obtain maximum benefit of these factors to get the best economy. Among other things discussed are the effect of high versus lower performance factors and the effect of different rear-axle gear ratios.
A comparison of a small, high-speed engine versus a large, low-speed engine is made along with data on the effects of engine friction and mechanical efficiency, since it is evident that any fuel economy obtained by reducing engine speed has really been due to the reduction of engine friction along with higher throttle operation for a given car speed.