Variable Geometry Compressors for Heavy Duty Truck Engine Turbochargers

Abstract

This paper presents the development approach, design, and evaluation of three turbocharger compressors with variable geometry for heavy duty engines. The main goal is the improvement of fuel economy without sacrifices regarding any other performance criteria. In a first step, a vaned diffuser parameter study shows that efficiency improvements in the relevant operating areas are possible at the cost of reduced map width. Concluding from the results, three variable geometries with varying complexity based on vaned diffusers are designed. Results from the hot gas test stand and engine test rig show that all systems are capable of increasing compressor efficiency and thus improving fuel economy in the main driving range of heavy duty engines. The most significant differences can be seen regarding the engine brake performance. Only one system meets all engine demands while improving fuel economy.

Experimentally Validated Extension of the Operating Range of an Electrically Driven Turbocharger for Fuel Cell Applications

“…They showed that a reduction in the leading edge angle results in a shift of the compressor operating range towards lower mass flow rates. By implementing an actuation mechanism, which allows the flexible pivoting of the diffuser vanes, the operating range of the compressor can be adjusted depending on the operating conditions [13,14]. However, gaps between end walls and diffuser vanes, which are necessary for a flexible pivoting concept, cause aerodynamic losses and thus reduce efficiency.…”