College of Engineering and Computer Science Mechanical Engineering Department Mechanical Engineering 370
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2 An automobile engine consumes fuel at a rate of 28 L/h and delivers 60 kW of power to the wheels. If the fuel has a heating value of 44,000 kJ/kg and a density of 0.8 g/cm3, determine the efficiency of the engine. We start with the basic definition of cycle efficiency,  , and we have to compute the heat input rate as the product of the fuel rate, and the heating content of the fuel. (We need the density to convert from a volume flow rate of fuel to a mass flow rate of fuel. Thus, we compute the heat input as follows.
We divide this into the power (work rate) of 60 kW to compute the efficiency.  = 21.9%
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