Exhaust gas cleaning system for engineering vehicle

Abstract

An exhaust gas cleaning system is provided in an engineering vehicle such as a hydraulic excavator. During automatic regeneration, when a gate lock lever 5 is in a locked state and work is not performed, the exhaust gas temperature detected by the exhaust temperature detecting device 37 may be lower than the threshold value, so temperature-rising assistance is started as follows. The minimum engine output PS 1 (pump discharge pressure P 1 and pump discharge amount Q 1 ) is brought to engine output PS 2 (pump discharge pressure P 2 and pump discharge amount Q 2 ). In this way, a hydraulic load is applied to an engine to thereby increase exhaust gas temperature. When the work is resumed during the regeneration, an operator pulls down the gate lock lever to the first position A, and the engine output is returned to PS 1. Thus, the temperature-rising assistance is stopped, however the automatic regeneration is continued.

What is claimed is: 
     
         1 . An exhaust gas cleaning system for an engineering vehicle including a diesel engine, a driven body driven by power of the engine, operating means for commanding the driven body to operate, and operation stopping means for stopping the operation of the driven body, the system comprising:
 a filter device disposed in an exhaust system of the engine and including a filter for capturing particulate matter contained in exhaust gas;   a regeneration device adapted to increase temperature of the exhaust gas to burn and remove particulate matter deposited on the filter;   a regeneration control device adapted to control the start and stop of operation of the regeneration device; and   temperature-rising assistance means for assisting temperature-rising of the regeneration device;   wherein the regeneration control device starts the operation of the temperature-rising assistance means when the operation stopping means is operated to stop the operation of the driven body during the operation of the regeneration device.   
     
     
         2 . The exhaust gas cleaning system for an engineering vehicle according to  claim 1 , further comprising:
 an exhaust temperature detecting device adapted to detect temperature of the exhaust gas;   wherein the regeneration control device starts the operation of the temperature-rising assistance means when the operation stopping means is operated to stop the operation of the driven body and the exhaust temperature detecting device detects temperature lower than a threshold value during the operation of the regeneration device.   
     
     
         3 . The exhaust gas cleaning system for an engineering vehicle according to  claim 1 ,
 wherein the regeneration control device stops the operation of the temperature-rising assistance means when the operation stopping means is operated to release the stop of the operation of the driven body.   
     
     
         4 . The exhaust gas cleaning system for an engineering vehicle according to  claim 1 ,
 wherein the engineering vehicle includes a hydraulic pump driven by the engine, and   the temperature-rising means regulates at least one of the discharge pressure and discharge amount of the hydraulic pump and applies a hydraulic load to the engine.   
     
     
         5 . The exhaust gas cleaning system for an engineering vehicle according to  claim 1 ,
 wherein the engineering vehicle includes an engine control device adapted to control the engine, and   the temperature-rising assistance means commands the engine control device to bring the rotation number of the engine to a predetermined rotation number higher than an idle rotation number during the operation of the regeneration device.   
     
     
         6 . The exhaust gas cleaning system for an engineering vehicle according to  claim 1 ,
 wherein the operation stopping means is a gate lock lever selectively operated between the first position where the operation of the driven body is enabled and the second position where the operation of the driven body is disabled.   
     
     
         7 . The exhaust gas cleaning system for an engineering vehicle according to  claim 1 ,
 wherein the operation stopping means is a parking brake operated to brake travel motion during parking of the engineering vehicle.   
     
     
         8 . The exhaust gas cleaning system for an engineering vehicle according to  claim 1 ,
 wherein the operation stopping means is a shift lever selectively switched among a forward movement position, a neutral position and a rearward movement position.