| 摘要 |
<p>PURPOSE:To aim at enhancing the accuracy of detection by connecting a pressure sensor selectably to the upstream and downstream sides of both filter trap and muffler disposed in an exhaust pipe from an internal combustion engine so as to measure the pressure differential across each of the filter trap and the muffler by use of only one pressure sensor. CONSTITUTION:A filter trap 2 and a muffler 4 are disposed in an exhaust pipe 1 from an internal combustion engine. In this arrangement, one pilot pipe 13a from a pressure sensor 13 is connected to the exhaust pipe 1 between the filter trap 2 and the muffler 4, and the other pilot pipe 13b is connected selectively to a plurality of pilot pipes 15, 16 through a selector valve 14. Further, the pilot pipe 15 is connected to the exhaust pipe 1 upstream of the filter trap 2 while the pilot pipe 16 is connected to the exhaust pipe 16 downstream of the muffler 4. Accordingly, it is possible to measure the pressure differential across each of the filter trap 2 and the muffler 4 by use of the pressure sensor 13 alone by changing over the selector valve 14.</p> |
