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Some special features of the turbocharged gasoline engine are discussed in comparison with the turbocharged Diesel engine. The influence of compression-ratio, temperature of the charge air, air/fuel-ratio and ignition-timing on combustion, fuel economy and power output is shown. A combined compressor- and engine air-flow-map of the turbocharged gasoline-engine is developed and the features of a compressor matching the special requirements of a TC gasoline engine are deduced from this map. The position of the throttle in the intake-system, which has great influence on governing-qualities and load-change-responce of a turbocharged gasoline engine is discussed and the problems and disadvantages of a waste-gate governed turbocharger especially in connection with a gasoline engine are figured out.

The main noise sources of a diesel passenger car are determined and possible noise level reductions are assessed. Primary damping measures such as influencing it by means of modifying the combustion itself as well as secondary measures such as encapsulation are described. A vehicle-supported encapsulation of the engine utilizing parts of the body is discussed in more detail. A research vehicle was built. A description of design function, and practical realization of such a vehicle-supported encapsulation including the necessary development of a new cooling system is given. Finally, the maximum possible reduction of the external noise levels using this design as well as the problems connected with encapsulation - such as the resulting increase in internal vehicle noise and vehicle weight, reduced ground clearance and maintenance accessibility - are reported and critically evaluated.

For study purposes, an improved Pressure-Wave Supercharger (PWS), without belt drive, was investigated and adapted to a Mercedes-Benz passenger car diesel engine. Tests were performed both on the test bench and in a car of the Mercedes-Benz compact class. Characteristics, advantages and drawbacks of the new system will be shown and discussed.