No abstract

Single Cylinder Diesel Engines are simple and very economical in manufacturing. Their multipurpose usability and the capability to deliver the maximum power possible within a given envelope makes them very demanding engines in the market. Simulation tools are widely used nowadays to minimize the energy and time needed for a real engine design and development. Zero-dimensional models are very suitable and reliable to observe the engine operation under different conditions. Contrary to the previous studies, this paper presents a comparison between the practical and simulation model data of a single cylinder Diesel Engine. The purpose of this research was to investigate the fundamental variations between the simulation and experimental results with the help of characteristic engine performance maps. Experiments were conducted on a practical 1.16 L Diesel Engine under variable conditions which were then repeated on the simulation model to analyze and evaluate the differences between the obtained results. Zero-dimensional modelling was performed using GT-Power, a powerful commercial engine simulation software. This study also involved the prediction of optimum speed (RPM) of the engine by performing a vibration analysis using a wireless accelerometer. The maximum torque of the 1.16 L Erin Engine is given to be 80 Nm @ 1,800 RPM, while the simulation model indicated it to be 78 Nm at the same RPM value. Likewise, maximum power output was indicated to be 18 kW @ 2,400 RPM, while the experimental results showed it to be 15 kW @ 2,400 RPM. These results laid down a liable basis for the prediction of several operating parameters of the engine which could act as a solid rung for further studies on this subject.

No abstract

With emission legislation becoming ever more stringent, declining fossil resources and an increase in greenhouse effect caused by CO 2 emissions, manufacturers are exploring new ways to match the emissions regulations without compromising on the performance of the engine. This study included development of zero-dimensional model of a 2.0 L turbocharged diesel engine and then study the effects of changing its compression ratio in the numerical model. This paper gave a framework in determining the effect of compression ratios in different operational conditions of the engine. Implementation of variable compression ratio technology on a numerical model proved to be very cost-effective, time saving and validated the fact that numerical models can be used to study different parameters of the engines during the development stage. The main effect of an increase in compression ratio, was found to be as expected, a decrease in brake specific fuel consumption and an increase in thermal efficiency with a greater impact at low rpm-low load regions. Assuming, that the variable compression ratio technology can be utilized in the engine, this work found the best combination of compression ratios around the engine map, giving a best fit of trade-offs between the emissions and performance of the engine. This study also validates the fact that variable compression ratio technology, if implemented in the engine could not only reduce emissions of the engine but can be given as an option to the end-user to switch to more economic fuel consumption values during idling or cruising at long distant journeys.

Engines have improved a lot and reached a new state of the art in terms of combustion technology, but they alone still fall short in achieving emission limitations without any trade-off on performance. Selective Catalytic Reduction (SCR) is the key technology used to meet the increasingly strict Nitrogen Oxides (NOx) emission regulations. The injection of Urea Water Solution (UWS-32.5% urea solution) upstream the catalyst is currently the leading technique for reducing the emission of NOx from the exhaust (DeNOx). A uniform distribution of the spray droplets is very crucial to achieve a good conversion efficiency. Therefore, the size and velocity distribution of the droplets are of high importance in deciding the fate of the DeNOx process. This article describes an approach of modelling the UWS spray and its validation against experimental data collected under realistic exhaust-like conditions. Droplet size distributions and velocities were recorded using Phase Doppler Anemometry (PDA) in a high-temperature wind tunnel. Simulations of the spray were performed using a commercial Computational Fluid Dynamics (CFD) code, ANSYS Fluent, in Lagrangian solver framework under the same flow conditions.The results show that initializing the droplets with the correct diameter and velocity distributions is a vital element in determining the fate of droplets and their impingement location. Using the proposed methodology, validation of diameter and velocity distributions were performed and the average deviations in Sauter Mean Diameter (SMD) were found to be less than 8%. Deviations in velocity distributions were recorded with larger differences appearing in planes closer to the nozzle. It was seen that the simulation initiated with the correct momentum had an average difference of around 8% whereas the simulation initiated with a single velocity value had an average difference of around 32%, when compared with the actual measurement data.