Quote:
Originally Posted by srishiva  Regarding the question about density and volume, wasn't there a article a year ago wherein it was mentioned that petrol stations made crores of rupees by not adjusting the volume to temperature ? |
Since the fuel is stored on an average 2 meters below the surface, the temperature is relatively constant and is not likely to affect the volume of fuel delivered from the nozzle. We lose more money by other sharp practices done by the petrol stations; e.g. it is possible to trickle out about 0.5-1 litre of fuel from the filling pipe without the meter reading the trickle - the next guy in loses that much petrol but pays for the meter reading, which assumes fuel was full till the filling nozzle. Better to go to a station where they know you and wouldn't try tricks, or wait in a queue, rather than going to a station where there is no one.
What stumped absar was a common phenomenon called 'gas lock'. The pump attendant musn't have inserted the filler far enough into the filling inlet: the fuel going in must have foamed in the filling pipe leading to the car's gas tank. This must have resulted in fuel rushing back out and causing the spill. Foaming does not cause enough back pressure to trigger the fuel to stop. Try filling a narrow neck bottle from a tap full on and you will realize what happens!
The reduction in density with increase in temperature is more apparent in gas / vapour and less apparent in liquids (water is at it's densest at 4 DegC!). That is the reason for using Intercooler between a turbocharger and intake manifold - turbo compresses air increasing it's temperature and reducing the density of air (and oxygen); the intercooler reduces the temperature of the pressurized air to get more air (and oxygen) into the intake manifold. More oxygen = better burning = better power and burning efficiency = better FE (fuel as well as forex efficiency: we import fuel!
).
For naturally aspirated engines, the difference is easily noticeable between winter and summer in North India.