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KF_BZ Brake Cylinder table

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    KF_BZ Brake Cylinder table

    Hey guys,

    I'm trying to figure out how the DME controls the air shut-off valve for the suction jet pump which provides additional vaccuum to the brake master cylinder. The shut off valve closes off fresh air from the intake plenum pre-throttle (not under vacuum).

    I found this table, KF_BZ_WDK_VL which I believe controls this valve. I'm guessing this is a throttle angle threshold vs. RPM to shut off the valve?

    I could see it working two different ways, one where the valve would close during high vacuum (when additional vacuum is not needed and to prevent an additional (metered) vacuum leak, or that it would close at full throttle to prevent vacuum from escaping the master cylinder/booster, although this seems less likely as I believe there is a check valve on the booster side. It would make the most sense for this valve to be *open* during conditions where there is only small vacuum after the throttle (part load) as the suction jet pump helps increase vaccuum to the booster. Anyone have any more info?

    That's not a Brake Cylinder map (BZ - Betriebszustaende = Operating Condition). It is the % throttle position at which the maps switch from partial to full load.