Variable Displacement pumps

[treetotreef]

hi

Can someone explain to me how a variable displacement pump works in a power steering system and the benifits of it, if any?

cheers

rich

 

[GregLocock]

The benefit is fuel consumption, and reduced pointless heating of the fluid (same thing really). You might even be able to do away with an oil cooler on a large vehicle.

I don't know how they vary the flow rate, there's probably some sort of variable dead volume in the pump, or they could be really nasty and just short the output back to the input (which is what a conventional pump does to limit the pressure). They could use a swash plate design, but that sounds a little esoteric for the cheap and nasty world of PAS pumps.






Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[patprimmer]

If it is a sliding vane pump, they could move the axle relative to the swept surface of the housing.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[GregLocock]

Cheap ones seem to be sliding vane

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.