This paper presents the results of an analytical study to identify the essential features of a futuristic engine for cars. A combination of several advanced features in one engine package results in a dramatic increase in the fuel economy of the car while maintaining all other essential features at comparable levels to current cars on the market. This advanced adiabatic diesel (AAD) engine is expected to give 78.8 mpg in the Federal Combined Driving cycle in a 3,000-pound vehicle. This compares to 37.7 mpg and 30.0 mpg obtained in current diesel and gasoline engine powered cars, respectively. The study identified the research and development efforts needed to bring this concept to fruition and concluded that an aggressive 10-year program will result in production availability of these cars.