The performance characteristics of a diesel fuel piloted syngas compression ignition engine are presented in this thesis. A stock Hatz 1D81 engine was converted to operate in dual fuel mode through the elimination of the governor system and addition of an in-cylinder pressure transducer and custom intake system to facilitate the mixing of the gaseous fuel and combustion air. The engine was run on a Superflow water brake dynamometer and benchmarked with diesel to compare against manufacturer specifications. This was followed by dual fuel operation on methane and syngas, with the results being compared through performance characteristics. When operated on methane, the engine attained higher peak in-cylinder pressures along with higher torque, power, and thermal efficiency values for equal equivalence ratios. It was necessary to use greater amounts of syngas to reach comparable results with methane due to the lower energy content of syngas. The ignition delay was greater for syngas, and the onset of knock occurred earlier with syngas in comparison to methane. The heat release, Q, was comparable for both fuels and the exhaust gas emissions were significantly lower for operation with syngas. With emphasis on clean engine operation, syngas operation proved to be viable due to its renewable nature, significantly lower exhaust gas emissions, equal heat release characteristics, and larger useable operating range when compared to methane. / Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2012-05-28 15:02:49.227

Controlling ignition timing and flame stabilization is one of the most outstanding challenges limiting the development of modern, efficient and low-emission compression ignition engines (CIEs). In this study, the role of turbulence on two-stage ignition dynamics and subsequent flame stabilization at diesel engine conditions is assessed by performing direct numerical simulations in a simplified inflow-outflow premixed configuration. The thermochemical conditions are chosen to match those of the most reactive mixture in the Engine Combustion Network’s n-dodecane Spray A flame (temperature of 813 K, pressure of 60 atm, equivalence ratio of 1.3, and with 15% vol. O2 in the ambient gas). Inflow velocities 4 to 16 times larger than the laminar flame speed are considered. As a result, in the absence of turbulence, ignition and flame stabilization are controlled by advection and chemistry, diffusion being negligible. Ignition delays match those of the homogeneous reactor and both the cool flame, due to low-temperature chemistry (LTC), and the hot flame, due to high-temperature chemistry (HTC), are spontaneous ignition fronts. Turbulence alters this picture in two ways. First, the second-stage (HTC) ignition delay is increased considerably, in contrast with the first-stage (LTC) ignition delay, which remains virtually unaffected. Second, a sufficiently high turbulence intensity makes the cool spontaneous ignition front transition to a cool deflagration which moves upstream to the inlet, while the hot flame is pushed downstream, still stabilized by spontaneous ignition. The latter phenomenon is caused by the reduced reactivity of LTC products as the cool flame transitions from spontaneous ignition to deflagration. Further increasing the turbulence intensity leads to both cool and hot flames transitioning to deflagrations. For the hot flame, the mechanism governing this transition is the increase in magnitude of progress variable gradient under increased turbulence or reduced inflow velocity, while in cool flames it is mainly due to the reduction in chemical source terms. In addition to turbulence intensity, the role of inflow velocity, integral length scale, and oxygen concentration level on this transition is assessed and modeling challenges are discussed. Finally, a chemical explosive mode analysis is provided to further characterise the ignition and transition phenomena. The present results highlight important fundamental roles of turbulence expected to modulate CIE combustion dynamics.

A 12.9 L heavy duty compression ignition engine was tested with strategies for dual fuel optimization. The effects of varied intake manifold pressure as well as split-injection strategies at a load of 5 bar BMEP and 85 PES were observed. These results were used to allow testing of split-injection strategies at a higher load of 10 bar BMEP at 70 PES that were void of MPRR above 2000 kPa/CAD. The split-injection strategies at 5 bar BMEP showed that lower BSNOx can be achieved with minimal drop in FCE. Varying intake manifold pressure revealed that combustion occurs earlier in a cycle with increasing intake manifold pressure and indirectly increasing FCE. A load of 10 bar BMEP at 70 PES should only use split-injection strategy to maintain load without high MPRR as efficiency drops with dependency on the second injection.

On-board hydrogen and syngas production is considered as a transition solution from fossil fuel to hydrogen powered vehicles until problems associated with hydrogen infrastructure, distribution and storage are resolved. A hydrogen- or syngas-rich stream, which substitutes part of the main hydrocarbon fuel, can be produced by supplying diesel fuel in a fuel-reforming reactor, integrated within the exhaust pipe of a diesel engine. The primary aim of this project was to investigate the effects of intake air enrichment with product gas on the performance, combustion and emissions of a diesel engine. The novelty of this study was the utilisation of the dilution effect of the reformate, combined with replacement of part of the hydrocarbon fuel in the engine cylinder by either hydrogen or syngas. The experiments were performed using a fully instrumented, prototype 2.0 litre Ford HSDI diesel engine. The engine was tested in four different operating conditions, representative for light- and medium-duty diesel engines. The product gas was simulated by bottled gases, the composition of which resembled that of typical diesel reformer product gas. In each operating condition, the percentage of the bottled gases and the start of diesel injection were varied in order to find the optimum operating points. The results showed that when the intake air was enriched with hydrogen, smoke and CO emissions decreased at the expense of NOx. Supply of nitrogen-rich combustion air into the engine resulted in a reduction in NOx emissions; nevertheless, this technique had a detrimental effect on smoke and CO emissions. Under low-speed low-load operation, enrichment of the intake air with a mixture of hydrogen and nitrogen led to simultaneous reductions in NOx, smoke and CO emissions. Introduction of a mixture of syngas and nitrogen into the engine resulted in simultaneous reductions in NOx and smoke emissions over a wide range of the engine operating window. Admission of bottled gases into the engine had a negative impact on brake thermal efficiency. Although there are many papers in the literature dealing with the effects of intake air enrichment with separate hydrogen, syngas and nitrogen, no studies were found examining how a mixture composed of hydrogen and nitrogen or syngas and nitrogen would affect a diesel engine. Apart from making a significant contribution to existing knowledge, it is 3 believed that this research work will benefit the development of an engine-reformer system since the product gas is mainly composed of either a mixture of hydrogen and nitrogen or a mixture of syngas and nitrogen.

Student Number : 9707408V - MSc(Eng) research report - School of Mechanical, Industrial and Aeronautical Engineering - Faculty of Engineering and the Built Environment / This research is an investigation into the performance and combustion characteristics of a two-cylinder, four-stroke compression ignition engine fuelled on diesel and then on dimethyl ether (DME). Baseline tests were performed using diesel. The tests were then repeated for dimethyl ether fuelling. All DME tests were performed at an injection opening pressure of 210 bar, as recommended for diesel fuelling. The tests were all carried out at constant torque with incremental increases in speed and an improved method of measuring the DME flow rate was devised. It was found that the engine’s performance characteristics were very similar, regardless of whether the engine was fuelled on diesel or DME. Brake power, indicated power and cylinder pressure, during the highest loading condition of 55 Nm, were virtually identical for diesel and DME fuelling, with the most significant finding being that the engine was more efficient when fuelled on DME than when fuelled with diesel. Another interesting finding was that the energy release of diesel decreases with increasing load, whilst the energy release of DME increases with increasing load. At the highest loading condition of 55 Nm, the energy release of DME was approximately 210 joules higher than that of diesel. This investigation concluded that DME may definitely be a suitable substitute fuel for diesel.

[pt] Há algum tempo biocombustíveis renováveis são potenciais soluções sugeridas às questões de emissão de poluentes e dependência da sociedade aos derivados fósseis. Biodiesel e etanol são combustíveis comerciais renováveis candidatos à substituição das fontes fósseis, especialmente, em motores de ignição por compressão, os quais são tipicamente mais eficientes do que aqueles de ignição por centelha. Misturas ternárias de diesel, biodiesel e etanol formam estratégias de substituição parcial do diesel aplicáveis em motores de ignição por compressão sem a necessidade de grandes adaptações. Nesta dissertação realizaram-se avaliações experimentais em um motor multi-cilíndrico de ignição por compressão (MWM 4.10 TCA), abastecido com misturas de diesel, biodiesel (até 15 por cento em teor volumétrico) e etanol anidro (até 20 por cento em teor volumétrico). Cada mistura ternária é composta por diferentes proporções do álcool e sempre com a concentração volumétrica de 1 por cento de um aditivo estabilizador da mistura. Portanto, os testes associam substituições parciais do diesel por biocombustíveis a avaliações de desempenho do motor e da combustão das misturas, sob algumas condições de carga, regimes de rotação e instantes de injeção de combustível. Os testes realizados indicam que misturas com 20 por cento em volume de concentração de etanol experimentam inícios de combustão até 4,7 graus CA mais atrasados. Porém, a busca de instantes otimizados na injeção de combustível trouxe melhorias ao desempenho do motor, permitiu conversões energéticas mais vantajosas do etanol na ignição por compressão frente à ignição por centelha, além de minimizar efeitos do etanol em retardar o início da combustão. / [en] Renewable biofuels have been proposed for a long time as an alternative to the issues concerned to pollutants emission and also society s liability to fossil fuels. Biodiesel and ethanol are renewable commercial fuel candidates for fossil fuels substitution, especially, in compression ignition engines, which are typically more efficient than the spark ignition ones. Diesel s partial replacement, such as the substitution by ternary blends formed by diesel, biodiesel and ethanol, is a strategy applicable to compression ignition engines without the need of further modifications. In this dissertation tests were run in a multi-cylinder compression ignition engine (MWM 4.10 TCA), fueled with diesel, biodiesel (up to 15 percent in volumetric content) and anhydrous ethanol (up to 20 percent in volumetric content) blends. Each mixture should be composed by different alcohol s proportions and always containing a 1 percent volumetric concentration of additive in order to ensure ternary s blend stability. Therefore, tests try to ally diesel s partial replacement by biofuels with engine performance and blends combustion assessment, under some combinations of load, engine speed and injection timing conditions. The tests performed indicate that the start of the combustion experienced up to 4.7 degrees CA postponements, when fueled with a 20 percent ethanol volumetric concentration blend. Still, optimized injection timing investigation brought improvements to engine performance, allowed better ethanol energetic conversions through compression ignition when compared to spark ignition and could also minimize delays caused by ethanol s presence in the beginning of the combustion.

[pt] Para substituir parcialmente a demanda em óleo diesel de origem fóssil, reduzir os elevados custos de importação e respeitar as normas ambientais, políticas sustentáveis já levaram a substituir parcialmente óleo diesel por biodiesel. Entretanto, outras tecnologias, como as misturas diesel-biodiesel-etanol, estão sendo investigadas. O principal desafio dessas misturas consiste em melhorar a miscibilidade e a estabilidade do álcool no óleo diesel. No presente trabalho, formulou-se um aditivo original, a partir de compostos renováveis, que permitiu melhorar a faixa de concentração de etanol anidro dentro de óleo diesel com 15 por cento em volume de biodiesel e de temperatura onde observa-se misturas estáveis. Diversas propriedades físico-químicas das misturas aditivadas foram medidas em uma larga faixa de concentração de etanol para avaliar os aspetos de consumo, qualidade da combustão, comportamento a baixa temperatura, interação entre fluido e superfície, e segurança. Os resultados obtidos mostraram que misturas com, pelo menos, 1,0 por cento em volume de aditivo e até 20 por cento em volume de etanol anidro são estáveis para temperaturas superiores a 10 graus Celsius e respeitam a maioria das especificações brasileiras atuais para óleo diesel. Ensaios experimentais em um motor de ignição por compressão MWM 4.10 TCA (Euro III) foram realizados com estas misturas. Os resultados obtidos mostraram que a substituição do óleo diesel altera as características da combustão: o crescente teor de etanol leva ao aumento do atraso de ignição, à liberação de calor mais rápida e à diminuição da pressão máxima. Mesmo nessas condições não otimizadas de injeção e de combustão, os resultados mostraram uma melhor conversão da energia química no etanol para produzir potência efetiva, comparado com os valores encontrados nos motores flex fuel de ciclo Otto, além de um pequeno aumento no rendimento térmico do motor. / [en] In order to partially replace the demand of fossil diesel fuels, to reduce high import costs and to comply with environmental standards, sustainable policies have led to partially replace diesel fuel by biodiesel. However, other technologies, such as diesel-biodiesel-ethanol mixtures, are being investigated. The major challenge of these mixtures is to improve the miscibility and the stability of alcohol in diesel fuel. In this study, an original additive, from renewable compounds, improved the miscibility of anhydrous ethanol in diesel fuel with 15 per cent by volume of biodiesel and temperature in which stable mixtures were observed. Several physicochemical properties of the additivated mixtures were measured in a large range of ethanol concentration to evaluate aspects of consumption, combustion quality, behavior at low temperature, interaction between the fluid and the surface, and safety. The results showed that blends with, at least 1.0 per cent, by volume of additive and 20 per cent by volume of anhydrous ethanol are stable at temperatures above 10 degrees Celsius and respected most of the current Brazilian specifications for diesel fuel. Experimental tests on a compression ignition engine MWM 4.10 TCA (Euro III) were performed with these mixtures. The results showed that the diesel fuel substitution alters the characteristics of combustion: the increased ethanol content implied an increase of the ignition delay, a faster heat release and a decrease of maximum pressure. Despite these non-optimized conditions for injection and combustion, results showed a better conversion of ethanol chemical energy into brake power, in comparison to the values found in flex fuel spark ignition engine, in addition to a small increase in the indicated efficiency of the engine.

The diploma thesis is focused on analysis of noise level of mobile power vehicles in relation to motor operation mode and its evaluation. The thesis core lies within measurement of acoustic pressure levels at four vehicles in different motor operation modes by two audio-noise meters. One meter was places within the cabin, the other outside. The results of the work showed a development in reducing noise at modern power vehicles.

The object of this thesis was Proposal and Examination of Supercharging Alternatives of CI-engine with Exhaust Gas Recirculation according required engine power parameters. This goal was meet by use of Turbocharger with Variable Nozzles and Air-Air intercooler.