Patent ID: 9228474
Filing Date: 2016-01-05
CPC Classification: B60W,F01N,Y02A,Y02T

Claim Text:
1. A method of determining failure of a urea quality sensor, comprising: determining, by a control unit, whether a urea temperature detected by a urea temperature sensor is higher than a predetermined temperature; determining by the control unit, if the urea temperature is higher than the predetermined temperature, whether a vehicle speed detected by a vehicle speed sensor is faster than a predetermined vehicle speed; determining by the control unit, if the vehicle speed is faster than the predetermined vehicle speed, whether a difference between a current urea quality and a previous urea quality, each detected by a urea quality sensor, is higher than a predetermined urea quality; determining, by the control unit, whether a failure occurs based on a signal transmitted to the control unit from the urea quality sensor relating to the current and previous urea qualities; storing by the control unit, a failure code if the difference between the current urea quality and the previous urea quality is higher than the predetermined urea quality; and the control unit warning the driver and restricting the engine output, restricting the vehicle speed, or prohibiting starting.