Emissions and performance of diesel engine using blends of waste cooking oil methyl ester (biodiesel) and diesel

Date of Publication


Document Type

Master's Thesis

Degree Name

Master of Science in Chemical Engineering


Gokongwei College of Engineering


Chemical Engineering

Thesis Adviser

Susan A. Roces
Nathaniel P. Dugos
Michael Angelo B. Promentilla

Defense Panel Chair

Raymond R. Tan

Defense Panel Member

Jose Bienvenido Manuel M. Biona
Marylou Uy


The emissions and performance of a four-cylinder, four-stroke cycle, direct injection diesel engine fueled by waste cooking oil methyl ester (WCOME) and its blends in 20%, 40%, 60%, and 80% percentage volume bases were investigated at engine speeds of 6003,000 rpm, at idle and full load conditions, and the results compared with data using petroleum diesel as fuel.

Levels of smoke opacity and brake specific carbon monoxide (BS-CO), brake specific hydrocarbon (BS-HC), brake specific nitrogen oxide (BS-NOx), and brake specific sulfur dioxide (BS-SO2) were identified using emission analyses while levels of engine performance were defined according to brake horsepower (BHP), brake mean effective pressure (BMEP), brake specific fuel consumption (BSFC), and brake thermal efficiency (BTE).

Engine performance showed lower BHPs with a maximum average drop of 8.63% between B100 and diesel. As predicted, BSFCs were lowest for diesel fuel and highest for B100. The BTEs of diesel fuel were also lowest among the fuels tested, with an average difference of 19.93% between diesel and B100. Similarly, lower BMEPs were observed with a maximum drop of 8.63% on the average for B100.

Emissions analyses showed more than 50% reduction in BS-HC, BS-CO, BS-SO2, and smoke opacity when B100 was used, with the average reduction at 97.62%, 90.36%, 98.69%, and 76.19% respectively. BS-NOx were found to be much higher, especially with the engine test run on B100, with the average difference reaching 13,876.60%.

The properties of biodiesel blends (B20, B40, B60, and B80)namely, kinematic viscosity, density, acid value, cloud point, copper strip corrosion, distillation temperature range, pour point, sulfated ash, sulfur content, and gross calorific value were also tested and the results compared against ASTM Standard D6751. Except for acid value, all the results showed values that were far from the limit allowed for B100. It can be concluded, then, that biodiesel blends meet international fuel standards.

Abstract Format






Accession Number


Shelf Location

Archives, The Learning Commons, 12F Henry Sy Sr. Hall

Physical Description

leaves ; 4 3/4 in.

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