CONCENTRATION OF LIQUID REDUCING AGENT AND REMAINING AMOUNT DETECTION DEVICE

摘要

PROBLEM TO BE SOLVED: To ensure detection precision of both of concentration and remaining amount of liquid reducing agent when mounting a sensor outputting a signal related to concentration and remaining amount of liquid reducing agent by heat transfer characteristic between two apart points on a moving vehicle.

SOLUTION: When measurement trigger outputted per predetermined time after starting an engine is detected (S31), detection of concentration and remaining amount of liquid reducing agent is started by driving the sensor (S32) to read a vehicle condition indicating whether the condition continues for determining time after stopping the vehicle or not (S33). If the vehicle condition is stable (S34), concentration is calculated based on a signal from the sensor (S35) and is displayed in a densitometer visibly (S37) after updating concentration stored in a memory (S36). An alarm device is operated (S40) to urge replenishment of liquid reducing agent if remaining amount is zero after updating remaining amount stored in the memory (S39) by determining remaining amount based on a signal from the sensor (S38) irrespective of a vehicle condition.

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