Department of Mechanical and Mechatronic Engineering

Permanent URI for this community

https://scholar.sun.ac.za/handle/10019.1/109

Browse

Browsing Department of Mechanical and Mechatronic Engineering by Author "Albertyn, Louis Andre"

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    Influence of exhaust gas recirculation on performance of a turbocharged diesel engine running on biofuels blends.
    (2018-03) Albertyn, Louis Andre; Haines, Richard Walter; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
    ENGLISH ABSTRACT: Exhaust gas recirculation technology has been implemented with success in the automotive industry in reducing nitrogen oxides in diesel exhaust gas. Given that South Africa’s Clean Fuels programme currently adheres to Euro II fuel and emissions standards, research into the influence of exhaust gas recirculation on a more modern TDI engine running on locally sourced biofuel blends is done for this project. In this research project the existing engine test bench is upgraded by equipping the exhaust gas recirculation system as well as the compressor of the variable geometry turbocharger with various sensors and instrumentation. All the data acquired from the sensors is logged by a graphical user interface program developed in LabVIEW. National Instruments data acquisition devices USB 6351 and USB 4350 are interfaced with LabVIEW to obtain the recorded data. Further improvements include the addition of a water-to-air intercooler developed in-house to control the charge air temperature. An eddy current dynamometer replaces the previous hydraulic dynamometer to improve steady state speed and torque control of the engine. Experiments were performed on two biofuel blends, B20 and E10, using crude derived pump fuel as the base fuel. Both biofuel blends were splash blended and mixed by volume. The B20 blend consists of twenty percent biodiesel, obtained from waste cooking oil, and eighty percent base fuel. The E10 blend consists of ten percent ethanol mixed with the ninety percent base fuel. All fuels are refined locally. The control of the exhaust gas recirculation is maintained as per the original equipment manufacturer. The focus of this study is therefore to determine how exhaust gas recirculation affects a diesel engine optimised to run on ultra-low sulphur diesel and how it responds to running on different biofuel blends in terms of fuel consumption, temperatures and emissions of specifically nitrogen oxides. Results suggest that there is little to no variation in brake specific fuel consumption at the partial loads tested. The emission of nitrogen oxides does not deviate significantly between the fuels, however a marked reduction in soot is noticed for the E10 blend. Carbon monoxide concentrations are also higher for the E10 blend at high speed, low load operating points. As expected, nitrogen oxides are increased with the reduction in exhaust gas recirculation rate.