T. LE ANH, School of Transportation Engineering, Hanoi University of Science and Technology, Vietnam, I. K. REKSOWARDOJO, Institut Teknologi Bandung, Indonesia and K. WATTANAVICHIEN,

Chulalongkorn University, Thailand

Abstract: This chapter summarises findings on the use of biofuels in conventional diesel engines. A number of biofuels such as vegetable crude oil, pure plant oil and biodiesel in different forms, which are derived from many types of raw materials such as jatropha, coconut, palm, kapok nut and cat-fish, are investigated to find the impact of these biofuels on the engine’s combustion characteristics, performance, exhaust emissions and durability. The concept of using biofuels in engines is also mentioned to determine ways of utilisation of biofuels in engines that match both the demands of biofuels use and the design of the engines.

Key words: biofuels utilisation, engine performance, exhaust emission, durability.

23.1 Introduction

Biofuels are now recognised as the most suitable alternative fuels for engines which were originally designed to use fossil fuels. Although the process of formation of fossil fuels still continues through the effect of underground heat and pressure, the current rate of consumption is higher than the rate of formation. Consequently, fossil fuels are considered to be non-renewable, that is, they are not replenished as fast as they are consumed. Biofuels, including ethanol, biodiesel and several other liquid and gaseous fuels, constitute a very promising renewable energy resource with the potential to displace the consumption of a substantial amount of petroleum worldwide during the next few decades.1-4 A clear trend in that direction is already in process.

Research on the production and utilisation of biofuels in engines is therefore regarded as a priority not only for developed nations but also for developing countries. Although the use of biofuels is currently low, the amount is continuously increasing in every country. However due to the fact that biofuels are produced from many different sources, characteristics and quality also vary, so the utilisation of different biofuels in internal combustion engines must be carefully investigated to determine the effects on engine performance and material components.

In this chapter the utilisation of biofuels in conventional diesel engines is considered. The use of crude jatropha oil (CJO), degummed jatropha oil (DJO), pure plant oils (PPOs), and biodiesels produced from crude palm oil (CPO), Jatropha curcas, coconut oil, kapok nut oil and cat-fish fat in neat form (100% biodiesel) together with various blends of biodiesel with conventional diesel is described. In addition, the use of mixed biodiesel derived from different raw materials is also considered as a possible solution for improving the quality of biodiesels.

Findings regarding the utilisation of biofuels in diesel engines are presented from case studies conducted in ASEAN (Association of Southeast Asian Nations) countries, especially Indonesia, Thailand and Vietnam, where high priority has been given to the development and use of biofuels.