THE TRANSPORT AND ROAD RESEARCH LABORATORY QUIET HEAVY VEHICLE PROJECT

Research into means of reducing noise from diesel-engined goods vehicles of 30-40 tonnes gross vehicle weight has shown that engine re-design can reduce noise from this component by 5-10 dB(A) within reasonable production, performance and cost constraints. Attention to the exhaust system, cooling package, engine covers and chassis design has resulted in a 10 dB(A) reduction in noise in the cab. Results are quoted from a number of experimental vehicle builds and the basis for a demonstration vehicle built to production standards which should meet a target drive-past noise level of 80 dB(A) is described.