Design and Development of Heat Recovery Steam Generation System for Automotive Engines

In view of the increasing energy demand due to rapid development in all the sectors, and a relative shortage of energy, the energy management with respect to internal combustion engines have gained more importance recently. Out of the total heat supplied to the engine in the form of fuel, approximately, 30 to 40% is converted into useful mechanical work. About 60% of the generated energy is still lost, half of which being exhaust heat, with the remaining half as heat absorbed by the engine cooling system resulting in an entropy rise and serious environmental degradation. This is so even after implementing the various technologies such as direct fuel injection, variable valve timing, exhaust-driven turbo charging, brake energy regeneration etc. Hence it is required to utilize this waste heat into useful work. The recovery and utilization of waste heat not only conserves fuel but also reduces the amount of waste heat and greenhouse gases which dampen the environment. A heat recovery steam generation system designed for 3.0 Liter BMW engine and amount of heat energy that can be utilized is discussed in this paper. It is found that around 20 to 30% of the engine brake power requirement may be met from this regeneration system at different engine loads and speeds of the engine.