| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device suitable for a construction machine having a hydraulic pump driven by an engine. <P>SOLUTION: The exhaust emission control device has: a urea water tank 10 provided in a hydraulic excavator and storing urea water to be supplied to an exhaust gas control means 9 performing processing for eliminating nitrogen oxides in exhaust gas exhausted from the engine 1; and a residual quantity detecting means 11 detecting a residual quantity of the urea water stored in this urea water tank 10, and also has a warning lamp 12 turned on when the residual quantity of the urea water reduces up to a first predetermined quantity A, and an engine speed limiting means provided in a controller 7 and gradually reducing a maximum engine speed of the engine 1 up to a predetermined value in a range for operating a hydraulic actuator included in a hydraulic driving circuit 8, for example, a limiting engine speed (n) being 70% of a maximum engine speed N at normal work, in response to reduction in its residual quantity, as the residual quantity of the urea water is reduced from the first predetermined quantity A. <P>COPYRIGHT: (C)2008,JPO&INPIT |
