Calculating Air Bag Inflation Rate for Exhaust Powered Vehicle Jack

[faiz513]

I am designing an exhaust powered vehicle car jack air bag. I have calculated the mass flow rate and velocity of the exhaust gases leaving the vehicles exhaust pipe. I need to calculate the amount of time it will take to inflate an air bag of a particular size. What equations do I need to be using in order to calculate the rate of inflation? Also I need to calcuate the stresses the air bag will have to withstand in order to lift the vehicle. I have taken fluid mechanics but I am having trouble figuring out which equations to use.

Thanks for the help...

 

[mgb_phys]

PV = nRT

 

[faiz513]

how would I get (n) for the above equation?

 

[mgb_phys]

n is the number of moles.
Mostly coming out of the exhaust is unburnt N2 (80%) of air, CO2 an H2O
You said you know the mass flow of exhaust, you can probably lookup the chemical composition of exhaust (it's probably in the clean air act etc) otherwise just assume air.
The tricky part is probably water, it will come out as a gas but condense in the bag.