Biodiesel is a renewable and decomposable fuel which is derived from edible and nonedible oils. It has different properties compared to conventional diesel but can be used directly in diesel engines. Different fuel properties characterise different combustionphasing parameters such as cyclic variations of Indicated Mean Effective Pressure (IMEP) and maximum pressure (Pmax). In this study, cyclic variations of combustion parameters such as IMEP and Pmax were investigated using a multi-cylinder diesel engine operating with conventional diesel and palm biodiesel. The experiments were conducted using different engine loads; 20, 40, and 60% at a constant engine speed of 2500 rpm. The coefficient of variation (COV) and standard deviation of parameters were used to evaluate the cyclic variations of the combustion phasing parameters for the test fuels at specific engine test conditions. It was observed that palm biodiesel has lower COV IMEP compared to conventional diesel but is higher in COV Pmax at higher engine loads respectively. In addition, palm biodiesel tends to have a higher recurrence for the frequency distribution for maximum pressure. It can be concluded from the study that the fuel properties of palm biodiesel have influenced most of the combustion parameters.

In this work, palm methyl ester (PME) was added to methanol-biodiesel fuel in order to reduce the emissions. For diesel engines, alcohols are receiving increasing attention because they are oxygenated and renewable fuels. Therefore, in this study, the effect of the PM emission level of a four-cylinder, naturally aspirated, indirect injection diesel engine has been experimentally investigated by using methanol-blended diesel fuel from 0% to 20% with an increment of 5%. The effects of methanol on particulate matter (Laurens, Koolwijk, & De Maat) components, soluble organic fraction (SOF) and dry soot (DS) using different types of fuel blend were investigated. Using a composite filter, the ester-methanol-diesel characteristics such as mass concentration in terms of PM, SOF and DS were analyzed under different engine operating conditions. The results show that the combination of 10% of methanol with 20% of palm methyl ester produces lower PM emissions. It is shown that PME20M10 of methanol-biodiesel fuel can reduce the PM emissions effectively for all load conditions.

This study focuses on a feasibility study of alternative nonedible crude oil such as jatropha and used cooking oil in biodiesel production. Crude jatropha oil (CJO) and used cooking oil (UCO) were converted to biodiesel using a two-step transesterification process with presents of acid-based and alkaline-based catalysts. Each three biodiesel blends (B5, B15 and B25) have been produced by blended with conventional diesel fuel (CDF). Determination of the fuel properties for each blend including CDF, Jatropha Methyl Ester (JME) and Used Cooking Oil Methyl Ester (UCOME) have been carried out. The average yield for jatropha and used cooking oil biodiesels production was 94.3% and 92% respectively. The increment of the percentage of JME or UCOME in its blends is proportional to fuels physical properties such as density, specific gravity, kinematic viscosity and surface tension, however inversely proportional to fuels calorific value. Based on the results of this study, it is acceptable to conclude that non-edible CJO and UCO are viable alternatives to edible oil as feedstock to renewable fuel in order to reduce the greenhouse gases produced.