Patent ID: 7829024
Filing Date: 2010-11-09
Classification: F01N,G01N,Y02T

Abstract:
1. A urea concentration identification device for identifying a urea concentration in urea solution stored in a tank, comprising: a concentration identification sensor unit; and a support unit having one end to which the concentration identification sensor unit is attached and the other end provided with a mounting unit to be attached to an opening of the tank, wherein the concentration identification sensor unit includes an indirectly-heated concentration detector having a heating element and a temperature sensing element, and a liquid temperature detector for measuring the temperature of urea solution, the indirectly-heated concentration detector has a heat transfer member for concentration detector for exchanging heat with the urea solution, the liquid temperature detector has a heat transfer member for liquid temperature detector for exchanging heat with the urea solution, and a cover member is attached to the concentration identification sensor unit so as to surround the heat transfer member for concentration detector and the heat transfer member for liquid temperature detector, the cover member forming a urea solution induction passage with an open upper end and an open lower end, the passage formed to allow the urea solution to flow from one of the open ends to the other of the open ends of the cover member while passing through the heat transfer member for concentration detector and the heat transfer member for liquid temperature detector, the urea solution induction passage extending in the longitudinal direction of the support unit, which is directed from one end to the other end thereof, wherein the concentration identification sensor unit is provided with an enclosure which three dimensionally encloses the periphery of the urea solution induction passage without covering both the ends of the urea solution induction passage, the enclosure is provided with a first communication hole and a second communication hole formed on one end plate and the other end plate thereof separated in the longitudinal direction, respectively, the first and second communication hole are located away from the extension of the urea solution induction passage so as to allow the urea solution to pass therethrough, and the second communication hole is so provided as to be separated away from a line which passes through the first communication hole and extends in the longitudinal direction, wherein a single-pulse voltage is applied to the heating element of the indirectly-heated concentration detector to make the heating element generate heat, and an identification operation unit identifies the urea concentration based on an output of a concentration detection circuit including the temperature sensing element of the indirectly-heated concentration detector and the liquid temperature detector, and wherein the identification operation unit identifies the urea concentration using a concentration correspondence voltage value corresponding to the difference between the initial temperature and the peak temperature of the temperature sensing element when the heating element generates heat.