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Turbocharging Concepts for Downsized DI Gasoline Engines

2004; Linguagem: Inglês

10.4271/2004-01-0036

2688-3627

T. H. Lake, John Stokes, R. Murphy, Richard H. Osborne, Andreas Schamel,

Electric and Hybrid Vehicle Technologies

Reducing engine swept volume (so-called 'downsizing') offers the potential to meet future tighter CAFE standards and reduced CO 2 vehicle emissions in Europe. In downsizing the gasoline engine, a key challenge is controlling octane requirement without sacrificing fuel economy. The authors have investigated five alternative approaches on a turbocharged Dl gasoline engine: ○ Conventional stoichiometric operation, with reduced compression ratio (CR) ○ Lean Boost Dl (LBDI) with lean operation at full-load to control octane requirement while maintaining a high CR ○ EGR Boost with cooled EGR dilution rather than excess air to control octane requirement ○ Miller cycle concept, where valve-timing strategies are employed to reduce the effective compression ratio at high load ○ Dual injection strategies to control octane requirement Each approach has been investigated using engine performance and vehicle simulation codes. Experimental investigations have been carried out using a 1.125L 13 multi-cylinder engine. The most promising concept, LBDI, has been further developed using the multi-cylinder engine installed in a Ford Focus C-class vehicle.