Fuel and bhp calculations

[Swiss_Tony]

Does anyone know of the formula to work out how much fuel is required for a given amount of bhp?

 

And how much fuel a fuel pipe of a given size can flow at a set pressure?

 

Thanks in advance

 

James

Su77on Se7ens

 

[Colin Mill]

There is some info here. You will need to do some units conversion as its an American web page!

 

The volume flow rate down a pipe under laminar flow conditions is given by

 

Volume/second = (Pi*P*R^4)/(8*Eta*L)

 

Where Pi = 3.142, P = the pressure drop between the ends of the pipe( in Pascals), R is the internal radius of the pipe (in metres), Eta = the dynamic viscosity of the fluid(in Pascal.seconds), and L is the length of the pipe (in metres).

 

From a couple of sources I have that for viscosity conversion 1 cP = 0.001 Pascal·second

Petrol (gasoline) has a viscosity of around 0.6 cP at room temperature or 0.0006 Pascal.second but is a strong function of temperature.

 

Colin

 

Edited by - Colin Mill on 26 Jun 2007 20:16:38

[Peter Carmichael]

One of the easiest ways to check this is to run the fuel return to a bucket and measure the flow there. By definition, the FPR is setting the appropriate pressure and the pump is doing what it has to do to pump as much as poss at that pressure (at the fuel rail).

 

The simple rule of thumb is 0.5 lbs/hp/hour.

 

Fuel density is... .73722 kg/l according to wikipedia.

 

Therefore...

0.5/2.2/.73722=0.30763 litres/hp/hr

 

Or... 307cc/hp/hr

 

Or... 5.13cc/hp/min

 

So if you run your pump for a minute and you get 1.538 litres of fuel in your bucket then you have enough fuel flow at the set pressure for 300bhp.

 

You don't really have to worry about the fuel pressure drop in the supply pipe as long as the pressure drop across the fuel rail is low.

 

 

 

 

 

 

[Dickie Normuss]

What are you up to James? 😬

 

VX HPC - Loud and proud here

Watch out, whatever hits the fan will not be distributed evenly

[Swiss_Tony]

Thanks guys

 

I will get in the garage at the weekend 😬

 

Matt

 

As you know I have a large garden and my ride on petrol mower is playing up. I think it has a fuel starvation issue so I am trying to sort it so it runs nicely

 

James

Su77on Se7ens

 

[Colin Mill]

my ride on petrol mower is playing up

I feel slightly conned 😬 😬

[Swiss_Tony]

Dont Colin

ric is having a bit of a wind up as he knows perfectly well what the info is for

 

James

Su77on Se7ens

 

[Peter T]

Your strimmer?

 

R500 260 BHP Mango Madness

Project 'X' underway

[Colin Mill]

Hi James

 

Let me know if you need any help with the sums - I'm a cr@p driver but I do sums 😬

[Swiss_Tony]

Peter

 

Its for Project Y

 

Colin

 

Thanks YHM

 

James

Su77on Se7ens

 

[Doug phillips]

Hmmmmmmmmmmm ........................ so your van is playing up again James .

 

😬

 

Joint Surrey AR and Su77on Se7ener