With the legislation on environmental issues in Automotive Industry downsizing is one solution to reduce emissions. Engine and turbocharger manufacturers have made some significant improvement by selecting the suitable turbochargers for several different applications. Due to the increasing demands, the necessity for higher exhaust gas temperatures arose over the last decade. This has resulted in higher turbine stage temperatures. The material used to manufacture the housing for the turbine stage of the turbocharger has to retain its structural integrity at the elevated temperatures. However due to the design constraints there are some cracks which occur during the engine thermal cycle test in some locations in the turbine housings. If these cracks leak exhaust gases, the criterion for housing qualification has not been fulfilled. Therefore there is a need to validate the design before tooling and manufacturing of the turbine housing.
The current paper presents the results from a comprehensive set of experimental tests on a prototype active control turbocharger. This is a continuing series of test work as part of the development of this new type of turbocharger. Driven by the need to comply to increasingly strict emissions regulations as well as a continuing strive for better overall performance the active control turbocharger is intended to provide an improvement over the current state-of-the-art in turbocharging. In this system, the nozzle is able to alter the throat inlet area of the turbine according to the pressure variation of each engine exhaust gas pulse thus imposing a substantially more ‘active’ form of control of the conditions at the turbine rotor inlet.