Application of renewable fuels in ternary blends for the reduction of emissions in diesel engines

Van Niekerk, Adriaan

Abstract

The increasing use of biofuels to replace fossil fuels as well as more stringent emission regulations for internal combustion engines cause a challenge for the engine manufacturers to design engines that can cope with a wide range of fuels, but still offer low exhaust emissions.

In this work a compression ignition engine test bed has been used to measure emissions when using ternary fuel blends between diesel, biodiesel and ethanol as well as implementing Low Temperature Combustion (LTC) techniques.
A high fidelity simulation of the engine was also created to enable studies incorporating transient drive cycles to predict engine emissions.

The aim of this project was to determine a fuel blend that achieves a 10% renewable content as well as reduce legislated engine emissions. LTC was also used to further reduce the engine emissions running on the ternary fuel blend.
A mixture design of experiment (DoE) was used to optimise toward a fuel blend containing 2% biodiesel and 9% ethanol which results in a reduction of 34% in CO emissions, 10% in \NOx emissions and 21% in CO2 emissions compared to running the engine on pump diesel fuel.

The optimisation of a Central Composite DoE showed that NOx emissions can decrease a further 25% when the maximum exhaust gas recirculation is set to 45%, the main injection is retarded by 2 CADs, the pilot injection dwell time is set to 21 CADs and 20% of the fuel is delivered through the pilot injection.
CO emissions increase as a result of the increase in EGR percentage.

• Thesis Type: Thesis
• Deposit Date: Dec 12, 2019
• Publicly Available Date: Apr 2, 2020
• Public URL: https://uwe-repository.worktribe.com/output/4765174
• Award Date: Apr 2, 2020