A control message transmittingreceiving method in an MBMS-supporting mobile communication system. The coolant circulating system has a metal connecting pipe held by a first bracket attached to an upper end part of a first cylinder unit of the engine. Thus, as the gas mixture flows through the housing, the first gas will be adsorbed onto the adsorbent and the second gas will exit the housing through the outlet port. The magnetic field draws the magnetized oil toward the boom.