| 摘要 |
PURPOSE:To have at low costs a secondary air supply device with simple construction, good durability and easy servicing by providing a reduction of CO or HC generation owing to secondary air supply in the exhaust passage which does not require equipment of any special supply pump or the like. CONSTITUTION:Part of the air pressurized at a turbo-charger 5 and supplied to a prechamber 6 is fed into an exhaust pipe 3 through a secondary air supply line 11 and a check valve 12, where the CO and HC contained in the exhaust gas are combusted perfectly in the exhaust pipe 3 by this secondary air. When the pressure in the upper chamber 12b of check valve 12 is higher than that in the lower chamber 12c, i.e. when the pressure in the prechamber 6 is higher than that in the exhaust pipe 3, a reed 12e is opened to feed secondary air to the exhaust pipe 3 and when, by contraries, the pressure in the lower chamber 12c is higher than that in upper chamber 12b, the reed 12e is closed to prevent counterflow of the exhaust gas into prechamber 6. |
