After summarizing the experiences achieved with noise reducing enclosures of conventionally designed engines, the paper presents the design concept of a new low noise engine, being developed in the course of an external research and development project with the aim of creating an environmental projecting Diesel engine. The concept is characterized essentially by a vibration isolation between the vibration excited internal engine structure and the external engine casing, this isolation being effected by an especially developed elastic element. External engine casing and flywheel housing are designed as one part where transmission flow can be bolted on usually.The description of the results of fundamental investigation used for designing the vibration isolating element and the external engine housing as well as test results achieved on a prototype engine with the new designing principle represent a mean part of the paper.The prototype engine is a water-cooled 2,2 l Diesel engine with a direct injection system. Due to special designing details being described in another paper, the weight per HP is very low, lower compared to a conventionally designed engine of some output and speed without enclosure.The last part of the paper concerns the installation of the new engine type in vehicles. In this connection, some solutions for further simplification and increasing of the efficiency are demonstrated and discussed.