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The main aim of this study is to investigate the effect of NO and NO2 on the combustion characteristics such as pressure development and combustion phasing in natural gas HCCI engine. A secondary aim is to demonstrate a method of obtaining a significant sensitizing effect on methane oxidation reaction from small amounts of NOx. Experiments were conducted using a rapid compression-expansion machine that was constructed from a single-cylinder diesel engine. First, the sensitizing effect of NO and NO2 on the HCCI combustion of natural gas was investigated in a case where NOx was uniformly mixed into a charge. Obtained results show that the auto-ignition timing is significantly advanced and an acute heat release is promoted by adding either NO or NO2.

The objective of this study was to obtain an improved understanding of the effects of the simultaneous use of cold flow improver (CFI) and antioxidant on the cold flow properties, oxidation stability and diesel exhaust emissions of various biodiesels and biodiesel blends. Cold flow properties were evaluated by assessing the cloud point (CP) and pour point (PP) values, as well as from the results of the cold soak filtration test (CSFT). Oxidation stability was also determined by measuring the peroxide induction period (IP). The neat biodiesels (B100) derived from soybean oil(SME), Jatropha curcus oil(JME), rice bran oil(RBME), palm oil(PME) and waste cooking oil(WME), and biodiesel blends with JIS No.2 diesel fuel were tested. A CFI and antioxidant specially designed for use in biodiesel fuels were employed during the work. The experimental data demonstrated that the addition of antioxidant had no effect on either the CP or PP values.

High energy demand and environmental pollution leads to seeking of new, renewable and clean energy as biofuel and biomass. These fuels are abundant in tropical areas and agricultural-economic-based countries. Among various crops which are used for biofuel, Jatropha Curcas L. Oil (JO) is more beneficial and attractive as it is non-edible which is not competitive with food demand. In agricultural sector, the biomass waste especially from rice production such as rice husk is a tremendous resource in Cambodia. The combination of the use of biomass from rice husk (RH) and Jatropha Cake (JC) from the JO production in the gasification can produce more energy for the electricity production especially in the remote and rural area. In previous research, some researchers have been investigated on the use of JO in blending ratio, heated-neat condition and dual fuel combustion of diesel and bio-digested biogas.

This study focuses on deposit formation in a diesel engine fueled with straight vegetable oil (SVO) and its effects on engine performance and exhaust emissions. First, two-dimensional thickness distributions of the carbon deposits on the cylinder head were measured by a laser displacement meter after continuous engine operation on gas oil blended with SVO at 25%. The obtained results show that the carbon deposit thickness rapidly increases with SVO-blended fuel and reaches a higher level than with just gas oil. Second, the effects of fuel injector deposits on engine performance and emissions were examined. A small diesel engine was continuously operated by alternating between SVO and gas oil. Gas oil was injected for 1 hour before and after 6 hours of SVO operation to prevent the accumulation of SVO deposits inside the nozzle holes, and the process was repeated.