Optimum Design Point to Recover Maximum Possible Exhaust Heat Over the Operating Range of a Small Diesel Truck Using Bottoming Rankine Cycle
Abstract This paper focuses on waste heat recovery (WHR) system, which is an efficient technology to reduce fuel and vehicle carbon dioxide (CO2) emissions per kW of power produced. Wide variations of power of a vehicle make it difficult to design a WHR system which can operate optimally at all powers. The exhaust temperature from the engine is critical to design a WHR system. Higher the temperature higher will be the gain from the WHR system. However, as power drops the exhaust temperature drops which makes the WHR system perform poorly at lower powers. In this research, a small diesel truck engine was used to design a WHR system to produce additional power using a Rankine cycle (RC). The WHR system was designed at the rated power and speed of 42.8 kW and 2600 rpm, respectively. At this design point, around 15% additional power improvement was achieved resulting around 13% break specific fuel consumption reduction.