Development of Second Generation of Gasoline P-ZEV Technolgy 2001-01-1310
This paper describes the second generation of the partial zero emission vehicle (P-ZEV) technology that was developed for use on the Nissan Sentra CA sedan sold in California.1,2 The second-generation engine has been adopted on a mass-produced model marketed in Japan. Besides continuing the super ultra low emission vehicle (SULEV) performance of the Sentra CA, the second-generation technology incorporates a compact, two-stage HC trap catalyst system. The system has been substantially reduced in size and cost as a result of improving the catalyst and the substrate and reducing the total catalyst volume by optimizing the control method.
Moreover, the second-generation P-ZEV technology includes an electrically actuated continuously variable swirl control valve of the high-speed jet type, a high-response electrically actuated EGR valve and catalyst model control based on the use of an air-fuel ratio sensor. Besides contributing to low emission levels, these components are also used to achieve the maximum fuel economy improvement through innovative control of the engine operating conditions. As a result, the improved engine greatly reduces both fuel consumption and CO2 emissions to comply with Japan fuel economy standards to be enforced in 2010. These various improvements have resulted in the development of a production engine that combines outstanding emission performance with superior fuel economy to meet the environmental requirements of the 21st century.