Test Measurement Technique for Vehicle Cool Down Thermal Noises (Tick, Ping, Tink, Crinkle, Crackle)

Vehicle cool down noises are receiving more attention as the NVH quality standards rise. The typical observer describes these noises as ping/ting, tick/tink and crinkle/crackle. A new test procedure is presented that measures audible metallic type noises during vehicle cool down (after the engine has been shut off). Vehicle run conditions are recommended for noise replication in the field and for measurement standardization. An objective measurement system is described using sound pressure level. In the past, a measurement has been very difficult to quantify. A recommended report format concisely communicates this critical vehicle quality characteristic. It is a valuable tool for vehicle NVH comparison, ranking and benchmarking.