Unconventional thermal, mechanical, and nuclear low-pollution-potential power sources for urban vehicles. Paper presented at the International Automotive Engineering Congress, Detroit, Michigan, January 13-17, 1969.

This paper reviews a wide scope of unconventional thermal, mechanical, and nuclear systems and devices to determine which if any, might be suitable within the next 10 years for application as low-pollution-potential power sources for urban vehicles. It is concluded that of the many types of unconventional non-electrochemical power sources that are even conceptually possible as vehicle drives, only three appear to offer the near-future possibility of supplanting the I.C. engine in many urban automotive applications; Rankin-cycle engines (which includes steam), gas turbines, and Stirling-cycle engines.