The more and more worldwide downside concerning speedy economy development and a relative shortage of energy, the interior combustion engine exhaust waste heat and environmental pollution has been a lot of stressed heavily recently. Out of the overall heat equipped to the engine within the sort of fuel, around, thirty to four-hundredth is born-again into helpful mechanical work; the remaining heat is expelled to the atmosphere through exhaust gases and engine cooling systems, leading to entropy rise and high environmental pollution, therefore it's needed to use waste heat into helpful work. The recovery and utilization of waste heat not solely conserves fuel (fossil fuel) however additionally reduces the number of waste heat and greenhouse gases damped to atmosphere. The study shows the supply and risk of waste heat from combustion engine, additionally describe loss of exhaust gas energy of an indoor combustion engine. Many ways to recover the waste heat from combustion engine and performance and emissions of the interior combustion engine. Waste heat recovery system is that the best thanks to recover waste heat and saving the fuel.