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Controlled Auto Ignition (CAI), also known as Homogeneous Charge Compression Ignition (HCCI), is one of the most promising combustion technologies to reduce the fuel consumption and NOx emissions. Currently, CAI combustion is constrained at part load operation conditions because of misfire at low load and knocking combustion at high load, and the lack of effective means to control the combustion process. Extending its operating range including high load boundary towards full load and low load boundary towards idle in order to allow the CAI engine to meet the demand of whole vehicle driving cycles, has become one of the key issues facing the industrialisation of CAI/HCCI technology. Furthermore, this combustion mode should be compatible with different fuels, and can switch back to conventional spark ignition operation when necessary. In this paper, the CAI operation is demonstrated on a 2-stroke gasoline direct injection (GDI) engine equipped with a poppet valve train.

Controlled Auto-Ignition (CAI) also known as Homogeneous Charge Compression Ignition (HCCI) is increasingly seen as a very effective way of lowering both fuel consumption and emissions. Hence, it is regarded as one of the best ways to meet stringent future emissions legislation. It has however, still many problems to overcome, such as limited operating range. This combustion concept was achieved in a production type, 4-cylinder gasoline engine, in two separated tests: naturally aspirated and turbocharged. Very few modifications to the original engine were needed. These consisted basically of a new set of camshafts for the naturally aspirated test and new camshafts plus turbocharger for the test with forced induction. After previous experiments with naturally aspirated CAI operation, it was decided to investigate the capability of turbocharging for extended CAI load and speed range.

The effects of high quality biodiesel, namely, partially Hydrogenated Fatty Acid Methyl Ester or H-FAME, on 50,000km on-road durability test of unmodified common-rail vehicle have been investigated. Thailand popular brand new common-rail light duty vehicle, Isuzu D-Max Spacecab, equipped with 4JK1-STD engine (DOHC 4-cylinder 2.5L, M/T 4×2, Euro III emission) was chosen to undergo on-road test composed of well-mixed types of mountain, suburb and urban road conditions over the entire 50,000km. Jatropha-derived high quality biodiesel, H-FAME, conforming to WWFC (worldwide fuel charter) specification, was blended with normal diesel (Euro IV) at 10% (v/v) as tested fuel. Engine performance (torque and power), emission (CO, NOx, HC+NOx and PM), fuel consumption and dynamic response (0-100km acceleration time and maximum velocity) were analyzed at initial, middle and final distance; whereas, used lube oil analysis was conducted every 10,000km.

The effects of high quality biodiesel, namely, partially Hydrogenated Fatty Acid Methyl Ester or H-FAME, on 50,000km on-road durability test of unmodified common-rail vehicle have been investigated. Thailand brand new common-rail light duty vehicle, Isuzu D-Max Extended cab, equipped with 4JK1-TCX engine (DOHC 4-cylinder 2.5L, M/T 4×2, Euro IV emission) was chosen to undergo on-road test composed of well-mixed types of mountain, suburb and urban road conditions over the entire 50,000km. Palm-derived high quality biodiesel, H-FAME, conforming to WWFC (worldwide fuel charter) specification, was blended with normal diesel (Euro IV) at 20% (v/v) as tested fuel. Engine performance (torque and power), emission (CO, NOx, HC+NOx and PM), fuel consumption and dynamic response (0-100km acceleration time and maximum velocity) were analyzed at initial, middle and final distance; whereas, used lube oil analysis was conducted every 10,000km.

The measurement of the instantaneous flame temperature and soot concentration in the combustion chamber of a running diesel engine can provide useful information relating to the formation of two important exhaust pollutants, NOx and particulates. The two-colour method is based on optical pyrometry and it can provide estimates of the instantaneous flame temperature and soot concentration. The theoretical basis of the method is outlined in a companion paper. This paper deals with the practical problems involved in the construction of a working system, including suitable calibration techniques. The accuracy of the measurements of flame temperature and soot concentration is also discussed using results from a various sources.

The two-colour method is based on optical pyrometry and can readily be implemented at a modest cost for the measurement of the instantaneous flame temperature and soot concentration in the cylinders of diesel engines. With appropriate modification, this method can be applied to other continuous and intermittent combustion systems, such as those for gas turbine and boiler burners. This paper outlines the theoretical basis of the method, with particular attention being paid to the assumptions relating to the evaluation of the flame temperature and soot concentration. A companion paper deals with the practical problems involved in constructing a working system, including suitable calibration techniques, and assessment of the method accuracy.

Development of the diesel particulate filter (DPF) aims to attain fast oxidation of accumulated soot at low temperature. Numerous researchers have explored the characteristics of soot oxidation under ambient conditions of simulated exhaust gas using thermogravimetric analysis or a flow reactor. In this study, temperature programmed oxidation (TPO) experiments were carried out for soot entrapped in miniaturized DPFs, cut-out from practical particulate filters, yielding wall-flow features typically encountered in real-world DPFs. Furthermore, when using the miniaturized samples, highly accurate lab-scale measurements and investigations can be facilitated. Examining different temperature ramping rates used for the TPO experiments, we propose a rate of 10°C/min as the most effective in analyzing soot oxidation in the practical filter substrates.

A multi-functional membrane filter was developed through deposition of agglomerated Three-Way Catalyst particles with a size of 1 ~ 2 microns on the conventional bare particulate filter. The filtration efficiency reaches almost 100 % from the beginning of soot trapping with a low pressure drop and both reductions of NO and CO emission were achieved.

Direct injection gasoline engines have the potential for improved fuel economy through principally the engine down-sizing, stratified charge combustion, and Controlled Auto Ignition (CAI). However, due to the limited time available for complete fuel evaporation and the mixing of fuel and air mixture, locally fuel rich mixture or even liquid fuel can be present during the combustion process of a direct injection gasoline engine. This can result in significant increase in UHC, CO and Particulate Matter (PM) emissions from direct injection gasoline engines which are of major concerns because of the environmental and health implications. In order to investigate and develop a more efficient DI gasoline engine, a camless single cylinder DI gasoline engine has been developed. Fully flexible electro-hydraulically controlled valve train was used to achieve spark ignition (SI) and Controlled Autoignition (CAI) combustion in both 4-stroke and 2-stroke cycles.

Tumble and swirl motions in the cylinder of a four-valve SI engine with production type cylinder head were investigated using a cross-correlation digital Particle Image Velocimetry (PIV). Tumble motion was measured on the vertical symmetric plane of the combustion chamber. Swirl motion was measured on a plane parallel to the piston crown with one of intake ports blocked. Large-scale flow behaviours and their cyclic variations were analysed from the measured two-dimensional velocity data. Results show that swirl motion is generated at the end of the intake stroke and persists to the end of the compression stroke. Tumble vortex is produced in the early stage of the compression stroke and distorted in the late stage of the stroke. The cyclic variation of swirl motion is noticeable. The cyclic variation in tumble dominated flow field is much greater.

This research aims to characterize an arc generated soot that was utilized as a surrogate for diesel engine generated soot. The two laboratory generated soots used in this study are arc generated soot and diesel fuel-lamp flame soot. In order to benchmark these surrogates with diesel engine soot, characterization was done by analyzing their oxidation behaviors, organic elemental composition, and nascent nanostructures. After that, the arc generated soot was utilized in a time-lapse DPF regeneration experiment to investigate its partial oxidation phenomenon using FE-SEM as a visualization tool. As a result, it was found that, by the appearance, arc-soot can be used as a diesel engine soot surrogate to study the shrinkage phenomenon of soot on a DPF substrate.

A diesel particulate membrane filter (DPMF) offers good trapping efficiency of soot and reduces the pressure loss through the soot-trapping process. We found that one specific design of DPMF has the effect of reducing the apparent activation energy of the soot oxidation. The membrane is made of SiC nanoparticles with a diameter of 10-100 nm, which are covered with a thin silicon-oxy-carbide layer with a thickness of about 5 nm. The apparent activation energy of soot oxidation on the DPMF was reduced by 30-40 kJ/mol than conventional SiC-DPF. Furthermore, the light-off temperature of soot oxidation on the DPMF (with single nanosized Pt) is about 100°C lower than that of the DPMF (without Pt). The single nanosized Pt particles are embedded in the silicon-oxy-carbide layer. The formation of additional Pt is different from that which takes place in a conventional catalyzed soot filter (CSF). In a conventional CSF, the surface of the Pt particles is exposed to the atmosphere.

Natural Gas (NG) is currently a cost effective substitute for diesel fuel in the Heavy-Duty (HD) diesel transportation sector. Dual-Fuel engines substitute NG in place of diesel for decreased NOx and soot emissions, but suffer from high engine-out methane (CH4) emissions. Premixed Dual-Fuel Combustion (PDFC) is one method of decreasing methane emissions and simultaneously improving engine efficiency while maintaining low NOx and soot levels. PDFC utilizes an early diesel injection to adjust the flammability of the premixed charge, promoting more uniform burning of methane. Engine experiments were carried out using a NG and diesel HD single cylinder research engine. Key speeds and loads were explored in order to determine where PDFC is effective at reducing engine-out methane emissions over Conventional Dual-Fuel which uses a single diesel injection for ignition.

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.

The use of two different fuels to control the in-cylinder charge reactivity of compression ignition engines has been shown as an effective way to achieve low levels of nitrogen oxides (NOx) and soot emissions. The port fuel injection of ethanol on a common rail, direct injected diesel engine increases this reactivity gradient. The objective of this study is to experimentally characterize the controllability, performance, and emissions of ethanol-diesel dual-fuel combustion in a single cylinder heavy-duty engine. Three different diesel injection strategies were investigated: a late split, an early split, and an early single injection. The experiments were performed at low load, where the fuel conversion efficiency is typically reduced due to incomplete combustion. Ethanol substitution ratios varied from 44-80% on an energy input basis.

The automobile industry is under intense pressure to reduce carbon dioxide (CO2) emissions of vehicles. There is also increasing pressure to reduce the other tail-pipe emissions from vehicles to combat air pollution. Electric powertrains offer great potential for eliminating tailpipe CO2 and all other tailpipe emissions. However, current battery technology and recharging infrastructure still present limitations for some applications, where a continuous high-power demand is required. Furthermore, not all markets have the infrastructure to support a sizeable electric fleet and until the grid energy generation mix is of a sufficiently low carbon intensity, then significant vehicle life-cycle CO2 savings could not be realized by the Battery Electric Vehicles. This investigation examines the effects of combustion, efficiencies, and emissions of two alcohol fuels that could help to significantly reduce CO2 in both tailpipe and the whole life cycle.

The main aim of this work is to characterize the combustion phenomena and particulate matter in nano-size from the reactivity controlled compression ignition (RCCI) engine using neat hydrous ethanol as a low reactivity fuel. A four-cylinder diesel engine fueled with diesel (the volumetric blend of 95% petroleum diesel and 5% palm-based biodiesel) was operated on low and medium loads at 2,500 rpm without main diesel fuel injection modification and exhaust gas recirculation. Ethanol was injected at 1 bar pressure into the intake manifold while the w/w ratios of ethanol:diesel were varied between 0 and 0.77. An engine indicating system composed of an in-cylinder pressure transducer and a shaft encoder was used to investigate combustion characteristics using the first law of thermodynamics. A Scanning Mobility Particle Sizer and an Optical Particle Sizer were used to determine the particle number concentration and distribution over nano-size range.

Due to its potential for simultaneous improvement in fuel consumption and exhaust emissions, controlled autoignition (CAI) combustion has been subject to continuous research in the last several years. At the same time, there has been a lot of interest in the use of alternative fuels in order to reduce reliance on conventional fossil fuels. Therefore, this experimental study has been carried out to investigate the effect of alcohol fuels on the CAI combustion process and on the resulting engine performance. The experimental work was conducted on an optical single cylinder engine with an air-assisted injector. To achieve controlled autoignition, residual gas was trapped in the cylinder by using negative valve overlap and an intake air heater was used to ensure stable CAI combustion in the optical engine. Methanol, ethanol and blended fuels were tested and compared with the results of gasoline.

Lean-burn combustion is an effective method for increasing the thermal efficiency of gasoline engines fueled with stoichiometric fuel-air mixture, but leads to an unacceptable level of high cyclic variability before reaching ultra-low nitrogen oxide (NOx) emissions emitted from conventional gasoline engines. Multi-point micro-flame ignited (MFI) hybrid combustion was proposed to overcome this problem, and can be can be grouped into double-peak type, ramp type and trapezoid type with very low frequency of appearance. This research investigates the micro-flame ignition stages of double-peak type and ramp type MFI combustion captured by high speed photography. The results show that large flame is formed by the fast propagation of multi-point flame occurring in the central zone of the cylinder in the double-peak type. However, the multiple flame sites occur around the cylinder, and then gradually propagate and form a large flame accelerated by the independent small flame in the ramp type.

Biobutanol, i.e. n-butanol, as a second generation bio-derived alternative fuel of internal combustion engines, can facilitate the energy diversification in transportation and reduce carbon dioxide (CO2) emissions from engines and vehicles. However, the majority of research was conducted on spark-ignition engines fuelled with n-butanol and its blend with gasoline. A few investigations were focused on the combustion and exhaust emission characteristics of homogeneous charge compression ignition (HCCI) engines fuelled with n-butanol-gasoline blends. In this study, experiments were conducted in a single cylinder four stroke port fuel injection HCCI engine with fully variable valve lift and timing mechanisms on both the intake and exhaust valves. HCCI combustion was achieved by employing the negative valve overlap (NVO) strategy while being fueled with gasoline (Bu0), n-butanol (Bu100) and their blends containing 30% n-butanol by volume (Bu30).