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.