Browse Publications Technical Papers 2004-01-0036

Turbocharging Concepts for Downsized DI Gasoline Engines 2004-01-0036

Reducing engine swept volume (so-called ‘downsizing’) offers the potential to meet future tighter CAFÉ standards and reduced CO2 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 DI gasoline engine:
  • Conventional stoichiometric operation, with reduced compression ratio (CR)
  • Lean Boost DI (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 I3 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.


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