F1 engine mountings and stiffness.

[xpensive]

I couldn't help noticing the rather solid-looking mounting brackets on the CA2010 valvecovers.
Does anyone know more about engine mounting practices and stiffness in F1 cars? Scarbs?

[WhiteBlue]

Does anyone know more about mounting practices and stiffness in F1 cars? Scarbs?

It used to be a big issue for engines prior to the present minimum weight and CoG rule. Now you have to be dumb to screw up from the engine side. The tubs usually have inherent stiffness but the big opening templates and the high fuel loads may give reason to look at those figures as well. They have been given 15 kg more to cope with that and again they would be dumb to fail the rigidity requirements considering carbon fibre properties in honeycomb design. Designing for deflection targets is the most basic CAD task.

[xpensive]

Obviously, F1 designers are not as clever as yourself WB, however I doubt if any of them would be regarded as dumb.

It would be intersting though, if someone had something constructive to share on preferred methods of engine mounting?

[riff_raff]

xpensive,

As I'm sure you're well aware, F1 engines are a stressed chassis member. So the bending and torsional stiffness of the engine structure is of great importance. The most efficient way of maximizing the MOI of the engine structure is to transfer loads through the outer most parts of the engine (ie. the cam covers and sump). However, the difficulty in accomplishing this results from the deflections in the camshaft journals, crank main journals, and cylinder bores arising from these chassis loads.

The situation is compounded by the thermal mismatch that exists between a hot aluminum engine structure that has a large expansion rate, and the cool composite tub structure that has a much lower expansion rate. Many years ago, F1 designers got around this problem by attaching the engine to the tub with "blades" that were soft in bending but stiff in tension/compression.

Regards,
riff_raff

[xpensive]

All this makes a lot of much sense rr, but bolting to the valve cover still seems somewhat...I don't know.
Would be interesting to learn more about the lower attachements though, where most of the loads are likely to be?

Anyway that thermal xpansion is not to be played around with, if you imagine the distance between upper and lower boltings is 400 mm, Alu from 20 to 120 C will xpand roughly one millimeter.

[marcush.]

All this makes a lot of much sense rr, but bolting to the valve cover still seems somewhat...I don't know.
Would be interesting to learn more about the lower attachements though, where most of the loads are likely to be?

Anyway that thermal xpansion is not to be played around with, if you imagine the distance between upper and lower boltings is 400 mm, Alu from 20 to 120 C will xpand roughly one millimeter.

To map the thermal expansion of the engine is a straightforward job ,given you have one of the lumps in real ....
So the theory and reality will they match up ?
given you will really end up with something like 1 mm of grow you need to build a mount very stiff in bending but movable laterally for half a mill without any axial backlash.I´d say this is not a real tough one.
If you design the thing in a ways that you only reach the required clamping force at working temps (maybe a long steel bolt in an Aluminiumhousing) you are already creating a simple but possible solution..or not?

[riff_raff]

xpensive,

To give you an idea of how much of a problem chassis-induced loads are in an F1 engine structure, take a look at this picture of a Cosworth TJ V10 cylinder head. It vividly illustrates the difficulties in designing a long engine cylinder head structure for a stressed engine chassis like in F1:



Notice the big hollow beam section running the length of the cylinder head? And the vertical split lines for the cam journals? This engine was designed to take bending loads thru the head structure and not thru the cam covers.

Regards,
riff_raff

[marcush.]

xpensive,

To give you an idea of how much of a problem chassis-induced loads are in an F1 engine structure, take a look at this picture of a Cosworth TJ V10 cylinder head. It vividly illustrates the difficulties in designing a long engine cylinder head structure for a stressed engine chassis like in F1:



Notice the big hollow beam section running the length of the cylinder head? And the vertical split lines for the cam journals? This engine was designed to take bending loads thru the head structure and not thru the cam covers.

Regards,
riff_raff

this example obviously shows that the cam cover will be simply that ,a cover.
and the bearing caps have to go on separately ,no ladder .
I´m wondering if it were not possible to find a better solution and instead of having a bag of pieces do more integration and give parts more tasks to fulfill (bearings combined to a ladderframe increasing stiffness and doubling up as cam cover at the same time for example..just an idea.