A catalytic emission control apparatus of an internal combustion engine that has an engine stop mode of stopping the internal combustion engine during a run of a vehicle utilizes an oxygen absorption-storage action of an emission control catalyst disposed in an exhaust passage of the internal combustion engine. The wireless device identifies other wireless devices that service based upon transmission characteristics of wireless signals received from other wireless devices andor relative positions of the other wireless devices with respect to itself. Performance control occurs via addition of one or more additives to the fuel to adjust combustion characteristics.