QHV90 Project: Reduction of noise from lorry exhausts and air intakes (prediction program: lamps)

The work described in this report forms part of the Quiet Heavy Vehicles (QHV) for the 1990's project (QHV90) set up by the UK goverment in 1981. The project described in this report specifically deals with air intakes and exhaust silencers for heavy diesel engines. The objectives were to (i) develop test methods by which the acoustic performance of intake and exhaust silencers can be defined, with particular reference to vehicle external noise test conditions; (ii) to compare the predicted acoustic performance of silencers with measured performance, to improve the accuracy of predictions and to cover a range of silencer elements; (iii) to examine the effect of certain engine design parameters on the acoustic performance of silencers; and (iv) to develop computer programs (PRELAMPS AND LAMPS) to predict acoustic performance of silencers and to recommend a design and development procedure for air intake and exhaust silencers. Results were obtained on a naturally aspirated 6 litre diesel engine and a turbocharged 8 litre diesel engine.