| 摘要 |
<p>PURPOSE: To avoid damages of a soot-particle filter by moving a throttle valve from the full-open position to the minimum opening position immediately after shifting into the deceleration mode, and then, continuously returning the position to the full- open position. CONSTITUTION: An electronic control device 13 controls a shut-off valve 7, a vent valve 11 and a vacuum pump 5 based on the signal corresponding to the load signal XRS, the rotation signal (n), and the position of a limit switch 12. When an internal combustion engine is shifted into the deceleration mode and instantaneously operated under no load, the vent valve 11 is closed, and as soon as the shut-off valve 7 is opened, the vacuum pump 5 is regulated to the maximum carrying flow rate. The negative pressure in a pneumatic piping system 4 is introduced to a negative pressure cell 3, and a throttle valve 2 is moved to the minimum opening position 2'. The shut-off valve 7 is closed by the signal from the limit switch 12, the pneumatic piping system 4 is gradually vented through a throttling hole 10. The throttle valve 2 is continuously returned to the full-open position. The overheat of a soot-particle filter can thus be avoided.</p> |
