Abstract
Engine encapsulation is one of the effective measures to reduce engine noise that shares mainly part of accelerating noise of diesel truck. In this study, an open-frame capsule system encapsulation was applied to the engine and transmission, and a noise-absorbing measure was implemented on the rear surface of the carrying platform floor to reduce the noise emitted from the opening for permeability. As a result, it was confirmed by onboard test that acceleration running noise could be remarkably reduced while the cooling capacity required for actual running was maintained.