Mathematical equation help

[227bhp]

I've never been great at maths, but first off what does this ^ in an equation mean? I looked it up on Wikis list of symbols and it makes no sense to me, it states:

"logical conjunction or meet in a lattice
and;
min;
meet
propositional logic, lattice theory
The statement A ∧ B is true if A and B are both true; else it is false.

For functions A(x) and B(x), A(x) ∧ B(x) is used to mean min(A(x), B(x)). n < 4 ∧ n > 2 ⇔ n = 3 when n is a natural number.
wedge product
wedge product;
exterior product
exterior algebra
u ∧ v means the wedge product of any multivectors u and v. In three-dimensional Euclidean space the wedge product and the cross product of two vectors are each other's Hodge dual. "

Which doesn't sound right or mean much to me.

And er, secondly would anyone know how to do this?




Provided it's metric the answer will be somewhere around 700, if it needs to be imperial it's going to get even harder.
PI is probably 3.14 , * is presumably multiply

NInV = 2
InVD = 36
Throat % = 88
VSTD = 5.5

So I've got this far:
2 x 3.14 x ((36 x 88 divide 100) ^ 2 minus 5.5 ^ 2) divide 4

Any help muchly appreciated

[Vaud]

Raised to the power of. i.e. 2^2 = 2 squared = 4

I get 1528 but I may have made an error.

Edited by Vaud on Friday 30th November 10:09

[Vaud]

Is CSA = cross sectional area?

[droopsnoot]

Vaud said:

I get 1528 but I may have made an error.

I get that too, or 1529 really as I got 1528.9697

[Mammasaid]

droopsnoot said:

Vaud said:

I get 1528 but I may have made an error.

I get that too, or 1529 really as I got 1528.9697

1528.194668 using Pi as 3.14

[227bhp]

Vaud said:

Is CSA = cross sectional area?

Yes it is. The equation claims to give me the area of a port throat by using the valve dimensions and number of valves (per cylinder). Valve head is 36, stem 5.5 and throat (just before valve seat) is the percentage of the valve head (36).
Initially when I found it late last night I thought it was giving me the min CSA of a port ( which is much further upstream of the valve) which is what I want, but now in the cold light of day I think it's to work out the throat of a 2 inlet valve per cylinder engine in comparison to that of a one IVPC which isn't actually what I set out to find.

[PugwasHDJ80]

droopsnoot said:

Vaud said:

I get 1528 but I may have made an error.

I get that too, or 1529 really as I got 1528.9697

This- 1528.9697 (then an inifinite number of decimal places)

its very close to 1529.

[Vaud]

227bhp said:

Yes it is. The equation claims to give me the area of a port throat by using the valve dimensions and number of valves (per cylinder). Valve head is 36, stem 5.5 and throat (just before valve seat) is the percentage of the valve head (36).
Initially when I found it late last night I thought it was giving me the min CSA of a port ( which is much further upstream of the valve) which is what I want, but now in the cold light of day I think it's to work out the throat of a 2 inlet valve per cylinder engine in comparison to that of a one IVPC which isn't actually what I set out to find.

There is a different calculation here:

http://garage.grumpysperformance.com/index.php?thr... . (no PI)

[227bhp]

Mammasaid said:

droopsnoot said:

Vaud said:

I get 1528 but I may have made an error.

I get that too, or 1529 really as I got 1528.9697

1528.194668 using Pi as 3.14

Take an average: 1528.5 and then calculate the diameter from that, what would the figure be?
I can see a short cut here by simply using 88% of 36 = 31.68 which gives me an area of 788 x 2 = 1576 which is showing I need to scale down the % a bit.
I'm a bit confused now as to what the equation is actually working out...

[weeredmetro]

Its basically calculating the area that opens:

Area of valve surface is pi times the square of the radius. Radius is half the diameter

A = pi(Opening diameter/2)^2 = pi*(Opening diameter^2)/4

Diameter of the opening is the diameter of the valve times the throat percentage
Opening diameter = InVD*Throat%/100

Putting these two together gives

A = pi*((InVD*Throat%/100)^2) /4

When it's open, the valve stem blocks part of it, so this area has to be subtracted
Valve stem area = pi(VSTD/2)^2 = pi*(VSTD^2)/4

So total area is opening area minus valve stem area

Area = pi*( (InVD*Throat%/100)^2)/4 - pi*(VSTD^2)/4

This can be simplified by taking out pi/4 and sticking the rest in brackets (I've used square brackets to try to make it clearer):

Area = pi*[(InVD*Throat%/100)^2 - (VSTD^2)] /4

That's for one valve, if there are multiple valves, multiply by N

Area = N*pi*[(InVD*Throat%/100)^2 - (VSTD^2)] /4

Provided InVD and VSTD are in the same units (millimetres?), the answer will be in that unit squared (mm^2 ?)

Do the bits in brackets first!

[smithyithy]

X^2 is X².

I think ' ^ ' is just used when whoever is writing the text can't do the shortcut for ² (it's Alt 0178)

[funkyrobot]

£62.50.

[Krikkit]

smithyithy said:

X^2 is X².

I think ' ^ ' is just used when whoever is writing the text can't do the shortcut for ² (it's Alt 0178)

Correct - the whole formula is written lazily as they either a) couldn't be arsed or b) were too limited to do it in correct notation.

Either way, it's written with lazy variable names too.

Edited by Krikkit on Friday 30th November 14:49