The EURO-3 emission regulation will be enforced in the EU in 2006. To meet the regulation, emission reduction technologies were developed by using a test motorcycle with a water-cooled, four-cylinder, 1100cm3 engine. In order to reduce HC during cold-start cycle, catalyst was activated early and the fuel spray was atomized by means of combining Idle Air Control Valve System (IACV) with ignition retard. In order to reduce NOx during extra-urban driving cycle, number of cells and capacity of three-way catalyst were optimized, and air-fuel ratio was also optimized. However, the increase of catalyst capacity caused increase of exhaust resistance, and reduced engine power. In order to solve this problem, location of the catalyst was optimized. By these measures, the EURO-3 regulation value was sufficiently attained without detriment to the engine power and drivability.
Article of Honda R&D Technical Review Vol.16 No.2 (127 - 132)