A Study of Parameters Affecting Noise on a Heavy Duty DI Engine

On a 13 liter Direct Injection Heavy duty diesel engine, noise and cylinder pressure have been measured in order to investigate if noise can be estimated from cylinder pressure. The idea of filtering cylinder pressure to obtain noise has been tested. This idea implies that the engine works as a linear filter. The linear relation between cylinder pressure frequencies and noise frequencies seems quite poor and the method probably does not work on the engine tested.

When measuring noise, on the other hand, multivariate low order polynomials work well to study the trade-off between measured noise, fuel consumption, NOx and Soot. This implies that the huge datasets gathered with modern electronically controlled engines can be handled this way.