Development of a 4-Cylinder Gasoline Engine with a Variable Flow Turbo-charger

A newly developed 2.3L 4-cylinder gasoline turbo engine was designed to achieve high fuel economy and low tailpipe emissions, along with maximum torque equivalent to that of a 3.5L naturally aspirated engine to provide superior driving force for a compact class SUV. The production of this engine started in August of 2006, mounted on a new SUV in the U.S. market. This engine features an i-VTEC mechanism combined with a newly developed variable flow turbo-charger that delivers top-in-class fuel economy and superior dynamic performance while achieving the U.S. ULEV2 standard. In this paper, an outline of the newly developed gasoline turbo engine is described along with several key technologies employed to significantly enhance the steady state and transient characteristics of turbo-charged engines and methods to reduce the tailpipe emissions to meet U.S. ULEV2 standards.