Abstract
Recently, the oxygen storage capacity of TWC is focused on, and a purification of an engine exhaust gas is achieved fairly high level. However, the control system is seemed to be complicated to use such ability. To take advantage of this ability conveniently, a new control algorithm was investigated. The fuel injection mass was modulated periodically and the air excess ratio was detected at the TWC by an EGO sensor. The detected value was filtered by a moving average method and it was used for the periodic modulation control. Furthermore, two FF control system were equipped for fast response and stability. This simple and convenient control algorithm was investigated at transient state in many driving condition, good experimental results were obtained.
