Question

An ic engine consuming 20 liters of fuel per hour develops 60 kw power. Specific gravity of the fuel is 0.8 and its calorific value is 50 mj/kg. The thermal efficiency of the engine (in percentage) is

Answer 1

Indicated thermal efficiency

=total indicated power / energy in fuel per sec

=IP / mass*calorific value


Please don't forget to convert specific gravity of fuel into mass

Specific gravity=density of fuel/density of water

=mass of fuel/mass of water
Mass of fuel=specific gravity*mass of water


Thank u