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Turbocharged DISI engines with four cylinders have established in the market and provide a performance comparable to larger six-cylinder engines in the smaller compartment of a four-cylinder engine. In the Japanese market, also turbo gasoline engines with 500 - 660 cm₃ displacement have a long tradition in Kei-Cars. However, those engines show a lower specific performance as would be required for propelling typical small or compact vehicles in Europe. Recently, two-cylinder turbo engines have come to market, which are found attractive with respect to sound, package, and also enable low vehicle fuel consumption in NEDC test. The paper presents a turbocharger layout study on 2- and 3-cylinder engines. It discusses the influence of cylinder displacement volume on the sizing of turbines and compressors, and how specific flow phenomena in the turbine can be captured in the simulation model.

This paper describes an alternative catalyst aging process using a hot gas test stand for thermal aging. The solution presented is characterized by a burner technology that is combined with a combustion enhancement, which allows stoichiometric and rich operating conditions to simulate engine exhaust gases. The resulting efficiency was increased and the operation limits were broadened, compared to combustion engines that are typically used for catalyst aging. The primary modification that enabled this achievement was the recirculation of exhaust gas downstream from catalyst back to the burner. The burner allows the running simplified dynamic durability cycles, which are the standard bench cycle that is defined by the legislation as alternative aging procedure and the fuel shut-off simulation cycle ZDAKW. The hot gas test stand approach has been compared to the conventional engine test bench method.