Hot Surface Ignition of Performance Fuels

Ignition of flammable and combustible liquids by hot surfaces is a well-known hazard in motorsports where high-speed collisions and mechanical failures are common. In this paper, we present the results of 900 ignition tests of high performance fuels commonly used in motorsports applications including high-octane gasolines, nitromethane, and methanol. The results of the testing show that hot surface ignition is probabilistic in nature and cannot be defined by a single ignition temperature. It was found that hot surface ignition temperatures for the high-octane gasolines and methanol were several hundred degrees higher than published auto ignition temperatures for these fuels. While methanol has a higher octane number than standard gasolines, its hot surface ignition temperature was lower than gasoline. Nitromethane displayed ignition characteristics markedly different than the other fuels tested, igniting more than 200°C lower than gasoline blends and alcohols, and less than 50°C above its published auto ignition temperature.