A
Anonymous
Guest
Re: SG of diesel .....
Well, it is actually a measure of the overall efficiency of the engine, from the calories available in the fuel to shaft output. The work done is given by horsepower-hours (hp-hr) and the input chemical potential energy depends on the calorific value of the fuel, of course, and the quantity. Hence grammes per hp-hr. Other units could be used, but that's what Yanmar use. The SG is only needed if you want to equate grammes to litres and since most of us fill our tanks in litres, not grammes or Kg, that's pretty important if it is to be of any use. You could work with density rather than SG if you preferred, it's only a multiplier - all you are trying to do is convert the fuel quantity given in mass to volume.
Well, it is actually a measure of the overall efficiency of the engine, from the calories available in the fuel to shaft output. The work done is given by horsepower-hours (hp-hr) and the input chemical potential energy depends on the calorific value of the fuel, of course, and the quantity. Hence grammes per hp-hr. Other units could be used, but that's what Yanmar use. The SG is only needed if you want to equate grammes to litres and since most of us fill our tanks in litres, not grammes or Kg, that's pretty important if it is to be of any use. You could work with density rather than SG if you preferred, it's only a multiplier - all you are trying to do is convert the fuel quantity given in mass to volume.