5 replies to this topic

[Ben]

Has anyone had any experience of using an accumulator in place of a header tank to lower CG and/or run at higher pressure.

I remember a book published many years ago about Lola's 1993 F1 car that describes an "air spring tank" used ipo a header tank. The only thing I can find on the web is:

http://www.vaportrai...y-cell-psc.html

Ben

[Ben]

I've been sent an installation diagram by the supplier, and it indicates that yes it does blow-off from the unit into a catch tank. But isn't this the same as blowing the cap on a header tank?

So overall the advantage is running a lower CG of your water system because you don't need the head of water from an elevated header tank to maintain system pressure.

I'll find a pic of the Lola system from the book I mentioned and post that.

Ben

Edited by Ben, 15 December 2010 - 10:45.

[Tony Matthews]

So overall the advantage is running a lower CG of your water system because you don't need the head of water from an elevated header tank to maintain system pressure.


Ben

I may be missing something here, but how does the raised header tank contribute significantly to the overall system pressure? A couple of litres 150mm above the cylinder head, or in most cases, at the same height... Surely its position is mainly just helpful in filling and topping up.

[murpia]

That Vapor Trail PSC looks like a commercial version of the systems I've seen on many V engine single seaters (F1 & hillclimb) where the highest point of the whole coolant system is the cylinder heads.

I imagine getting the right amount of water into the engine could be tricky, and a bleed is required on the highest point(s) of the engine / coolers. Once filled & bled the normal pitlane procedure is to pre-heat the engine and then set the air spring pressure. The only air in the system should be in the air spring above the water column.

The advantages would be increased coolant pressure & low CoG.

Regards, Ian

[Fat Boy]

I think Ian pretty much has it. Another advantage is that because the water and air (nitrogen, pre-pressured) are separated that you aren't trying to use a liquid/gas froth to cool the car, just a liquid. With pre-pressuring things you can reduce the possibility of localized boiling because of the overall higher system pressure.

I've used several of the Vapor Trail products in the past, but not this particular one. In general, it's pretty good stuff. Be careful calling, you'll get your ear talked off.

[J. Edlund]

A normal engine cooling system use a coolant expansion tank where usually a lid with built in pressure relief valve is placed. As the coolant expand when the temperature increase the coolant level in the expansion tank will raise and shoud the pressure inside the tank become too high, the relief valve will open.

I suppose this system use some sort of accumulator instead, such as the bladder accumulator on the picture shown below which are very common in hydraulic systems. Using a accumulator instead of an expansion tank I suppose the system will be fully filled with water before the bladder in the accumulator is pressurized with air pressuring also the coolant system. As the coolant expand as it gets hotter the volume of the bladder will shrink in volume to compensate.