| 摘要 |
PCT No. PCT/GB92/02346 Sec. 371 Date Jun. 17, 1994 Sec. 102(e) Date Jun. 17, 1994 PCT Filed Dec. 17, 1992 PCT Pub. No. WO93/11983 PCT Pub. Date Jun. 24, 1994.An apparatus and method for controlling an electrically driven vacuum pump (16) for a motor vehicle provides that below a predetermined level of vacuum (approaching atmospheric pressure) the pump (16) runs at a first speed, and above that level of vacuum the pump (16) runs at a lower speed or is stopped. Pump control is by switching of a single pressure switch (21) between two states, switching from the first state to the second state being accompanied by a time delay to ensure a minimum running period at the first speed.
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