DEVICE FOR DISTINGUISHING LIQUID REDUCING AGENT AND EXHAUST EMISSION PURIFIER OF ENGINE

摘要

A device for distinguishing a liquid reducing agent which judges empty with higher precision as compared with prior art. The device for distinguishing a liquid reducing agent is provided with a concentration sensor and a water level sensor in a storage tank of liquid reducing agent, and characterized in that empty is judged by utilizing the water level based on the water level sensor in addition to the concentration based on the concentration sensor (step 3 and step 5). Even if a bubble is adhering to the concentration sensor and a wrong signal indicative of empty is delivered although the residual quantity of liquid reducing agent is sufficient, the water level sensor does not deliver a signal indicative of empty. Consequently, wrong judgment is prevented and accurate judgment can be made as compared with prior art.