摘要 |
A secondary air system providing a regeneration air pump wherein the vanes of the impeller are tapered from a point along the length of the vane to the root of the vane inside the air pump. The tapered vanes create desirable flow characteristics. The tapered vanes create a non-linear flow versus pressure characteristic. Thus, the tapered vanes in combination with a divider that extends circumferentially around the impeller and through the vanes causes the flow to increase. This non-linear characteristic created by the tapered vanes allows the secondary air system to maintain suitable operation at lower flow and pressure levels. Due to the tapered feature on the impeller, a dead head pressure is obtained at a lower pressure. The impeller arrangement also provides overall pump efficiency improvements.
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