Summary of Recent Research in Crash-Induced Vehicle Fire Safety

The research reported in this paper is a follow-on to a five year research program conducted by General Motors in accordance with an administrative Settlement Agreement reached with the US Department of Transportation. This paper is the fourth in a series of technical papers intended to disseminate the results of the ongoing research [Digges 2003, 2004, 2005]. This paper summarizes progress in several of the projects dealing with underhood fires and testing of a hydrogen fuel tank.

Calorimeter tests of underhood materials found a wide range of flammability for the structural plastics as well as the underhood sound insulation. Calorimeter tests of underhood fluids (lubricants and hydraulic fluid) showed that their flash points were less than 188°C and the minimum temperature of a hot surface to cause ignition was less than 325°C. Tests of four different vehicles to determine the exhaust manifold operating temperatures found a range between 241°C and 550°C. Analysis of state accident data indicated that pickups of the same model had higher fire rates when equipped with V-8 engines, compared to inline six engines.

A FMVSS-304-like bonfire test of a 5000 psi type 4 composite hydrogen tank documented the mechanical and chemical energy released when a tank bursts. Overpressures were large and this experiment demonstrated that the pressure relief device must work with very high reliability.