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Physicochemical characteristics of particulate matters which are influenced by engine oil additives from engine combustion of diesel and synthetic biodiesel: hydrotreated vegetable oil (HVO) were successfully investigated using electron microscopy, electron dispersive x-ray spectroscopy and thermogravimetric analysis. The agglomerate structure of diesel PM, HVO PM and diesel blending lubricant PM are similar in micro-scales. However, nanostructure of soot is a spherical shape composed of curve line crystallites while the metal oxide ash nanostructure is composed of parallel straight line hatch patterns. The oxidation kinetics of fuel blending lubricant PMs are higher than neat fuel PMs due to catalytic effect of incombustible metal additives from engine lubricating oil.

Diesel engines are high thermal efficiency because of high compression ratio but produce high concentration of particulate matter (PM) because of direct injection fuel diffusion combustion. PM must be removed from the exhaust gas to protect human health. This research describes biodiesel engine performance, efficiency and combustion behavior using combustion pressure analyzer. It was clearly observed that PM emitted from CI engines can be reduced by using renewable bio-oxygenated fuels. The morphology and nanostructure of fossil fuel and biofuel PMs were investigated by using a Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The morphology of biodiesel and diesel doesn’t have much different in the viewpoint of particulate matter trapping using DPF micro surface pores. The agglomerated ultrafine particles and primary nanoparticles sizes of diesel and biodiesel engine’s PM are approximately 50-500 nm and 20-50 nm, respectively.

Nowadays, human realize to the environment pollution cause from old engine and use the engine misapply. These engines will cause the problem such as air pollution and cannot use the engine to work at the maximum efficiency and fuel consumption. The new of control technologies can solve problems from misuse engine by an electronic control unit work with many sensors. Optimization of electronic control unit (ECU) makes an engine to work in maximum efficiency and decrease the environment pollution. In this research, Port-fuel injection spark ignition engine (PFI Engine) fuelled with gasoline is use as the boat engine. To use car engine as boat engine, the control system has to be modify and tune up for proper condition. For the method, the parameters that used to control and optimization are the boat's running condition to tune up injection timing, injection duration, ignition timing, and also the engine special function.

As well-known, the diesel engine has the highest thermal efficiency at the same load as compared with internal combustion engine but its disadvantage is particulate matter (PM) emitted to the atmosphere. The studies of this paper were divided into two parts. The first part studied the quantity of PM from the both diesel and biodiesel fuels at 80% load (2400 rpm) by the trapping process on diesel particulate filter (DPF) used in a partial flow dilution tunnel. The second part studied the regeneration process of PM under the flow rate of oxygen and nitrogen gas of 13.5 L/min with 10%, 15%, and 21% of oxygen gas. The result showed that amount of PM from biodiesel fuel was lower around two times than PM from diesel fuel. The duration in regeneration process of biodiesel's PM was shorter than diesel while increasing of oxygen percentage can reduce regeneration time.

Nanostructures of diesel and biodiesel engine particulate matters (PMs) were investigated by using a Transmission Electron Microscopy (TEM). The average single particle sizes of biodiesel and diesel PMs are approximately 30-40 nm and 50-60 nm, respectively. Image processing process was used to estimate each carbon platelet length by using TEM image. The average carbon platelet length of biodiesel and diesel PMs are in the range of 0.1-7.0 nm. Moreover, carbon atoms per cubic volume of PMs are approximately 500-900. The result shows that engine load and fuel property are strongly impact on the size of single particle and carbon atom density of particle. This is one of interesting behaviors need to be investigated for better understanding. The results of this research would be used as basic information for design and develop removing process of PM emitted from engine combustion which using in diesel and biodiesel fuels.

The increasing of global energy demand and stringent pollution regulations have promoted research on alternative fuels. In Thailand, ethanol, can be produced from many sources of national agriculture products as renewable fuel, which was strongly promoted by government due to its many merits for use in transportation field. In this study, combustion characteristics of ethanol-gasoline blend (20%, 85%, and 100%) as well as pure gasoline (E0) were investigated by using a swirl-generated constant volume combustion chamber. Flame propagations of different fuel blends were observed by high speed Schlieren photography technique while pressure history data were recorded for detailed combustion analysis. Combustion behavior, combustion duration and rate of pressure rise of all tested fuels were investigated in various swirl intensities and equivalence ratios. In addition, effect of swirl intensities and ethanol concentration on lean misfire limit were also discussed.

The present study aims to investigate the parameters affecting cold start characteristics of ethanol at low temperature, and suggest a solution to avoid cold starting problem without the installation of second fuel tank. The testing engine is a 125cc volume displacement, single-cylinder four strokes SI engine with fuel injection and ignition timing system controlled by ECU (electronic control unit). The cold starting performance tests were extensively conducted with different percentages of ethanol blends, surrounding temperatures, heating inside combustion chamber, heater injector, pre-cranking without fuel injection, and amount of fuel injection. From the experimental results, when using ethanol fuel in conventional engine, the problem of cold starting was observed at surrounding temperature lower than 20°C for ethanol. Increasing of injection duration can lower the possible cold start temperature of neat ethanol.

In Thailand, gasoline mixtures with 85% ethanol by volume so called E85 recently available with guaranteed lower selling price are expected to replace the former types of gasoline. The looming change leads to certain concerns on material compatibility with E85 for automobiles deliberately not designed to run by the blends. Fluid immersion tests complying with SAE and ASTM standard were performed to the parts. The metallic and polymeric parts were submersed in test fluids inside an oven in which temperature had been maintained at 55 ± 2°C for at least 2000 hours. Weekly collected data, i.e. physical appearances and physical properties, were statistical evaluated for parts' compatibility to E85 by comparing the data to those collected derived from the other parts submersed in E10 test fluid. A significant level of differences indicates incompatibility of a part with an assumption that the part is already compatible with E10.

The flow and mixing of fluid induced into the cylinder through each of the two intake ports of the spark ignition engine has been studied during intake and compression strokes on horizontal and vertical sections of the engine cylinder by experiment and numerical analysis. In the experiment in order to observe the flow and mixing process of fluid from each port, particles were alternately mixed with air flowing through each of the two intake pipes. And velocity vectors on the sections were measured by means of particle tracking velocimetry. The finite volume method was used in numerical analysis. Flow behavior and mixing of the fluid induced through each intake port were demonstrated in various crank angles and on various sections of cylinder during intake and compression strokes. Comparison between the experimental and numerical results were also made.