| 摘要 |
<p>An additive supply system includes an addition valve (6) for injecting additive into a catalyst (8), a main passage (2) for supplying additive in a tank (1) to the addition valve (6), a pump (4) provided in the main passage (2), a return passage (3) connected to the tank (1) and branching off the main passage (2), and a check valve (5), which prevents the additive from flowing from the return passage (3) to the main passage (2) and opens when the pressure in the main passage (2) is higher than or equal to a predetermined valve opening pressure. An electronic control device (10) performs draw-back control for drawing additive in the main passage (2) back into the tank (1) by rotating the pump (4) in reverse. Moreover, the electronic control device (10) drives the pump (4) to rotate forward with the addition valve (6) closed when executing filling control for filling the main passage (2) with additive after the draw-back control has been performed, and then opens the addition valve (6) and drives the pump (4) to rotate forward.</p> |
