High-Performance Rear- and Mid-Engine Vehicle Exhaust System Temperatures

Hot surface ignition of combustible material is a known cause of vehicle fires. Although the detailed mechanisms of hot surface ignition are highly complex, the surface temperature is known to play a crucial role in this process. There has been limited previous work in the literature on this topic, much of which has focused on engine or exhaust system surface temperatures of the most common types of passenger vehicles. Also, much of this work was done in an unrepeatable manner and suffered from measurement technique induced errors. The focus of the present work is on repeatable and low measurement technique induced error temperature measurements of exhaust system surface temperatures of rear- and mid-engine sports cars. Temperature measurements were made at several points along the exhaust systems of vehicles both with and without turbo chargers on a 5-mile oval track. The exhaust system surface temperatures were examined under conditions of transient acceleration and steady-state driving for vehicle speeds of up to 125 mph (201 km/h). Finally, the effect of engine rotation speed for a constant vehicle speed on exhaust surface temperature was examined. It was found that the exhaust temperatures of rear- and mid-engine sports cars have maximum surface temperatures that are within the range of temperatures reported in literature for passenger vehicles in the range of speeds for which comparison data exists. It was also found that increased engine rotation speed for a constant vehicle speed results in increased surface temperatures for all measured locations.