Exhaust gas cleaning device for internal combustion engine, has reverse suction controller device which propels pump in reducing agent reverse suction mode and varies reducing agent pumping mode

摘要

The exhaust gas cleaning device has a reducing agent container (21) to store a liquid reducing agent, and a pump (22) for pumping the reducing agent in the reducing agent container. A reverse suction controller device propels the pump in a reducing agent back suction mode and varies the reducing agent pumping mode, after the internal-combustion engine is stopped. The reducing agent is an aqueous urea solution is and nitrogen oxide reduction reaction for the reduction of nitrogen oxides is performed in the catalytic converter (13).