| 摘要 |
Before a large amount of PM is deposited in a filter, an exhaust gas cleaning system for a construction machine regenerates the filter to avoid a decrease in output due to the exhaust gas pressure rise occurring immediately before the filter is regenerated, and to reduce the likelihood of unusual increases in the internal temperature of the filter due to the combustion of the PM, associated with the execution of the regeneration, and consequential thermal damage to the filter. In a case where operator has a rest in the cabin of a hydraulic excavator during his or her work with the construction machine, when an operator maintains all internal operating devices in the cabin in a non-operational state with the engine 1 of the machine left running for a certain time, the controller 4 monitors the non-operational state. After this state continues for a predetermined time Ta, when the pressure sensed by a differential pressure sensor 36 is higher than a second predetermined pressure level P2, the controller 4 controls the rotating speed of the engine 1 to a predetermined speed Na before starting forced regeneration to burn off the PM deposited in a filter 32. When the pressure sensed by the differential pressure sensor 36 decreases below a first predetermined pressure level P1, the controller 4 terminates the regeneration automatically and returns the engine to normal control mode. |
