Sounds of Vehicle Internal Combustion Engines

Database DescriptionBy applying a specially developed acquisition system at the entrance to an underground garage, a total of 350 cars were sampled over four iterations. Based on the collected samples, a database containing 475 sound samples was formed.In the first three iterations, different approaches were applied regarding sample duration. Within all three approaches, one or two audio recordings per vehicle were obtained for most vehicles, where the first recording consistently represented the stationary engine idle mode without exception. In most samples, the second recording (in some cases the last one) partially contained the engine idle mode followed by an increase in crankshaft speed and a partial engine load mode for the purpose of vehicle acceleration. There were no cases in which the partial engine load mode appeared in the recordings before the idle mode.By applying an algorithm for extracting the idle mode from sound samples that, in addition to idle mode, also contained a change in operating mode, the moments up to which the signal remained stationary were determined. A smaller number of recordings were discarded as too short, while some recordings were shortened by extracting only the idle mode segment.After applying the idle mode extraction algorithm, which also eliminated electric vehicles, the final number of usable samples was 320.