From a view point of environment protection and energy saving on the world-wide basis low pollution, quieter and light-weight direct injection diesel engines for automotive use have been strongly requested. In order to meet these social requirements we have endeavoured to develop design methods for such engines available at the design stage.
Firstly, we have clarified relationship between vibration and radiated noise using simple 2 cylinder block model (1).
Secondary, we have successfully developed light-weight, better fuel economy and quieter multi-cylinder research engines which have potential to be able to meet more stringent legislative standards for noise and gas emissions to be expected in the late 80’s. This paper summarises mainly the process to develop multicylinder engine to be lighter and quieter and also refers to the effects compared to current ones.