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Exhaust gases from diesel engines can be an adequate source of energy to run a bottoming Rankine cycle to increase the overall efficiency of the engine as it contains a significant portion of input energy. In this research, an automotive diesel engine was tested to estimate the available energy in the exhaust gas. Shell and tube heat exchangers were used to extract the heat from the exhaust gas and the performance of the two shell and tube heat exchangers were investigated with parallel and counter flow arrangements using water as the working fluid. The results obtained were below satisfactory as these heat exchangers were purchased from the marketplace and not optimized for this particular application. Thus attempts were made to optimize the design of the heat exchanger by computer simulation using the available experimental data.

In this paper, a waste heat recovery (WHR) system is designed to recover heat from the exhaust of a diesel-gen-set having an engine of 26.57 kW. The Rankine Cycle (RC) and the Organic Rankine Cycle (ORC) are used to produce additional power using water, R113, R124 and R245fa as the working fluids. Water as the working fluid gives the best improvement of 13.8% power improvement with 12.2% bsfc reduction, but fails to produce any power at the lowest operating power of 5.8 kW due to lower exhaust temperature and higher boiling point of water. This is when the WHR system is designed at the rated power of 26.57 kW. Designing at lower power of 20.0 kW improves the enhancements at this and lower powers but reduces the improvement at the rated power of 26.57 kW. This design again fails to produce any power at the lowest power.

Design of the intake system of an internal combustion (IC) engine is one of the critical parameters to improve the performance of an engine. Induction pressure waves (compression and rarefaction waves) are created in the intake runner due to valve operations. If the intake runner is tuned correctly, a compression wave can boost the intake air flow improving the volumetric efficiency which increases the torque and power of the engine. In this research, the intake runner diameter and valve timing were varied individually, after which both were varied together to achieve optimum volumetric efficiency. A single-cylinder, four-stroke spark-ignited 510 cc naturally aspirated engine was used for the analysis. Simulations were carried out using engine simulation software Ricardo Wave to find the effect of intake runner diameter and timing on the engine performance.

To comply with the new Corporate Average Fuel Economy (CAFE) standards, automakers are expected to increase the average fuel economy of their vehicles to 54.5 miles per gallon from the current 24.8 miles per gallon by 2025. This research aims at proposing a feasible solution to narrow down the gap between the current and expected fuel economy of the vehicles, yet maintaining the engine’s original performance. A standard model of the KTM 510 cc single cylinder, fuel injected, internal combustion engine (IC) engine is modelled and simulated in Ricardo Wave software package to map the stock engine performance and specific fuel consumption at wide open throttle (WOT). The baseline simulation model is validated against the experimental readings with 98% accuracy.

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.

In this study, a 1.1 MW diesel-gen-set is used to design a Waste Heat Recovery (WHR) system to generate additional power using Rankine cycle (RC). A computer code is written in commercial Engineering Equation Solver (EES) software to solve equations of overall energy and mass balance, heat transfer, evaporation, condensation, frictional and heat losses for heat exchangers, turbine, pumps, cooling tower and connecting pipes connecting different components. After initial design of the WHR system, manufacturers are contacted to find out the availability of parts, and then, accordingly the design is changed. There are several heat exchangers required to heat the water from liquid to superheated steam and then, it is passed to the turbine. Then, after the expansion in the turbine, it is passed to the condenser to condense the steam to water. Optimization is done on the heat exchangers, focusing on the tube length and diameter.

The waste heat recovery (WHR) system appears to lower overall fuel consumption of the engine by producing additional power and curtailing greenhouse emissions per unit of power produced. In this project, a 25.5 kW diesel engine is used and simulated, which has an exhaust temperature of about 470°C. During optimization of the heat exchangers, the overall weight of the heat exchangers is kept low to reduce the final cost. Additionally, the overall pressure drops across the superheater, boiler, and economiser are kept at around 200 kPa to expel the exhaust gas into the atmosphere easily. To accomplish high heat-transfer across the heat exchangers, the pinch temperature of the hot and cold fluids is kept above 20°C. In this project, under the design constraints and available heat at the exhaust gases, the WHR system has enhanced the power and reduced the break specific fuel consumption by around 6.2% and 5.8%, respectively at 40 bar pressure.

Waste Heat Recovery System (WHRS) is used to extract heat from the exhaust gas from internal combustion (IC) engines to produce additional power with increase in overall efficiency of the engine. Amongst various WHRS, this paper focuses on WHRS using Rankine Cycle (RC) and Organic Rankine Cycle (ORC). A 100 kVA (80 kW engine) diesel generator was used for this research. Water, R245fa, and R134a were used as the working fluids for the cycle. To assess the performance of WHRS, the system was designed for 80 kW, 70 kW and 60 kW loads and then, for each designed load the WHRS was run for other loads and then compared. Assessment provide simulation results of RC and ORC using Engineering Equation Solver (EES) software. It was found that using water as the working fluid around 20% additional power was achieved. But it limited the working range of the system making it unsuitable for lower loads of 10 and 20 kW for this generator.