Engine Powered Machine

Abstract

An engine powered machine is provided with an economical exhaust gas purification system capable of avoiding overheating. The engine powered machine is provided with an exhaust gas purification system that injects a reducing agent into an exhaust pipe of an engine by a reducing agent feeder to detoxify nitrogen oxides in exhaust gases. A cooling fan, the driving or stopping of which is controlled by a controller, is arranged as a cooling device for a reducing agent tank in which the reducing agent to be injected by the reducing agent feeder is stored. When a detected temperature signal output from a reducing agent temperature detector has become higher than a cooling initiation temperature stored in a storage unit, the controller drives the cooling fan to initiate cooling of the reducing agent tank.

1 . An engine powered machine provided with an NOx removal catalyst arranged in an exhaust passage of an engine to selectively subject to reduction treatment nitrogen oxides that flow through the exhaust passage, a reducing agent tank for storing a reducing agent, a reducing agent feeder for injecting into the exhaust passage the reducing agent stored in the reducing agent tank, a reducing agent temperature detector for detecting a temperature of the reducing agent stored in the reducing agent tank, a cooling fan for cooling the reducing agent tank, and a controller for receiving a detected temperature signal outputted from the reducing agent temperature detector and controlling drive of the cooling fan, wherein:
 the controller has an input port for receiving the detected temperature signal, a storage unit in which a cooling initiation temperature for the reducing agent tank is stored, a computing unit for comparing the detected temperature signal with the cooling initiation temperature and, when the detected temperature signal has become equal to or higher than the cooling initiation temperature, outputting a drive signal for the cooling fan, and an output port for outputting the drive signal.   
     
     
         2 . The engine powered machine according to  claim 1 , wherein the reducing agent is a urea water, and the cooling initiation temperature is +35° C. 
     
     
         3 . The engine powered machine according to  claim 1 , wherein the reducing agent tank is provided on an outer wall thereof with cooling fins. 
     
     
         4 . The engine powered machine according to  claim 1 , wherein an electric motor or hydraulic motor is used as a power source for the cooling fan.