Advances in Turbocharging Technology and its Impact on Meeting Proposed California GHG Emission Regulations

The State of California considers greenhouse gases (GHGs) to be air pollutants and has directed the Air Resources Board to adopt cost effective regulations for GHG emissions from motor vehicles. The northeastern states and Canada through NESCCAF have worked closely with CARB and CO₂ equivalent emission regulations have been proposed. The eventual status of these regulations may not be clear, but what is clear is that there is a need to develop cost effective technology to reduce GHG emissions. This paper presents such technology.

Advances in turbocharging technology relevant to both gasoline and diesel engines are described. Turbocharging, as a technology has been around for 70 years, but just like the internal combustion engine itself, it is far from being mature. Conventional evolutionary development of turbocharging such as inertia reduction, aerodynamics and bearing improvements have been ongoing. More recent step improvements due to variable geometry technology both on the turbine and compressor side are now available. Work is under way on electrically assisted turbocharging as well as new concepts to meet the demands of exhaust gas recirculation. It is shown that turbocharging, applied to different classes of vehicles with appropriate choices of gasoline and diesel engines, provides a cost effective way of reducing GHG emissions well within the goals being considered by the California Air Resources Board.