Combustion of Diesel Fuel Blended with Partially Oxidized Biodiesel in a Direct Injection Compression Ignition Engine
Open Access
- Author:
- McGuire, Thomas Patrick
- Graduate Program:
- Energy and Geo-Environmental Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- None
- Committee Members:
- Andre Louis Boehman, Thesis Advisor/Co-Advisor
Yaw D Yeboah, Thesis Advisor/Co-Advisor
Andre Louis Boehman, Thesis Advisor/Co-Advisor - Keywords:
- diesel
biodiesel
renewable fuels
alternative fuels - Abstract:
- Many past studies have been conducted to address concerns over emissions from biodiesel fueled compression-ignition engines. These have shown that apart from increased emissions of oxides of nitrogen (NOx), biodiesel fueled engine emissions are equivalent or lower than for petroleum diesel fuel. An important property to consider for the future conversion to petroleum/bio diesel fuel blends is oxidative stability. Biodiesel has low oxidative stability leading to the formation of undesirable compounds and property changes many times faster than petroleum-based fuel when exposed to air. As a result it is necessary to investigate possible implications of having aged, or partially oxidized, biodiesel in future diesel fuel blends. An air-cooled direct-injected naturally aspirated Yanmar diesel engine with a custom designed exhaust gas recirculation (EGR) loop was chosen as the platform for the follow-up study due to its flexibility and low fuel consumption. Fuels chosen for the follow-up study consisted of oxidized and non-oxidized versions of both canola and soy methyl esters blended into B20 fuel blends. These four fuels along with a baseline PC-10 pure petro-diesel were all run at 3600 RPM and 75% load at both 0% and 10% EGR settings. B20 is the most widely promoted biodiesel blend and is specifically called for in the Energy Policy Act (EPAct) of 2005. The inclusion of EGR in the test protocol was because of the widespread use of EGR and a diesel particulate filter to achieve low emissions of both NOx and particulates in production engines. Blending partially oxidized biodiesel with petroleum diesel caused a decrease in total hydrocarbons (THC) and carbon monoxide (CO) emissions without a NOx penalty, even when compared with new biodiesel blends. There was however an overall penalty to NOx emissions seen as an increase with all B20 blends, commonly called the biodiesel NOx effect. As expected when EGR was added, all the fuels show a significant decrease in NOx emissions while holding constant or increasing total particulate emissions. However when B20 based on partially oxidized biodiesel and 10% EGR are used together, very low total particulate and low NOx are observed with both SME and CME.