| 摘要 |
Provided is an SCR sensor that does not degrade a measurement accuracy of a quality sensor even when a remaining amount of a urea tank is reduced. A quality sensor 122 is installed between a minimum remaining amount liquid level S and a bottom portion 105b of a urea tank 105; a drop pipe 131 is installed from a ceiling portion of the urea tank 105 to a top space in the urea tank 105; a support 174 is installed from the bottom portion to the ceiling portion of the urea tank 105; the quality sensor 122 and the drop pipe 131 are integrated through the support 174; and a bubble diffusion region B caused by the urea aqueous solution dropping from the drop pipe 131 is out of a sensitive region F of the quality sensor 122. |
