THROTTLELESS OTTO-CYCLE NATURAL GAS ENGINES. FINAL REPORT, JUNE 1, 1988-JANUARY 31, 1991

The report presents the results of an Exploratory Research contract aimed at establishing the feasibility of using preheated intake air for power and torque control in place of conventional throttling. The Throttless Otto-Cycle Natural Gas Engine (TONE) concept was proposed as a way to make vehicular use of natural gas-fueled engines more competitive. This research has shown that it is possible to increase operating efficiency, and therefore fuel efficiency and range using the TONE concept. In addition, and perhaps more importantly, TONE operation is accompanied by a substantial reduction in NOx emissions. This result was not predicted, and makes the TONE concept attractive beyond the potential for increased operating efficiency.