How Efficient is an Internal Combustion Engine?
There is a lot of concern nowadays about the efficiency of the internal combustion engine (ICE), and a lot of research is being done to improve it. But what exactly is the efficiency of the internal combustion engine and how do we measure it? The efficiency of any engine is simply calculated from the energy of the fuel supplied per unit time to do work and the output at the shaft of the engine after subtracting all losses. The input power of the fuel can be obtained from the mass of the fuel and its calorific value. The shaft output can be measured from a brake dynamometer. Simply put efficiency is Output/Input. The average ICE has an efficiency between 20 to 30%, which is very low. If we see a heat balance sheet of the internal combustion engines for a spark ignition or gasoline engine we find that the brake load efficiency is between 21 to 28%, whereas loss to cooling water is between 12 to 27%, loss to exhaust is between 30 to 55 %, and loss due to incomplete combustion is between 0
