The deactivation of a cylinder on a 1.0litre three cylinder turbocharged gasoline engine has been investigated providing novel information on thermal and fuel consumption effects associated with the technology. This comes in light of providing solutions to reduce fuel consumption and CO2 emissions resulting from internal combustion engines. The investigation has been carried out through the PROgram for Modelling of Engine Thermal Systems (PROMETS). A version of PROMETS was extensively developed to characterise a commercially produced TCE not fitted with cylinder deactivation technology. Developments include an improved gas-side heat transfer expression to account for increased heat transfer to coolant due to the addition of an integrated exhaust manifold; addition of an expression to represent natural convection to model heating of quiescent coolant in the block; and a method to estimate the boosted intake manifold pressure past the throttle due to turbocharging on a gasoline engine. The 0-D approach used in this thesis compared to higher resolution computational tools has allowed for thermal and performance predictions to be made within a couple of minutes compared to several hours or days. In effect, PROMETS has been a time and cost effective tool during the development stages of a prototype engine. The PROMETS model indicated that no adverse changes in engine thermal behaviour arose with cylinder deactivation. The largest temperature change of < 400 occurs in the exhaust valve lower stem for the deactivated cylinder. Temperature changes in other components throughout the engine are an order of magnitude smaller. Although the largest temperature differences between the deactivated and firing cylinders were found to be in the range of < 70 , these remain within normal engine operating temperatures of < 100 . Also, by on-setting deactivation past an oil temperature of 40 , warm-up times were marginally extended compared to operation on all cylinders from key-on. Experimental inputs representing changes in engine gross indicated thermal efficiency and the work loss associated with the motoring of a piston complemented modelling work in predicting fuel consumption changes due to deactivation. Reductions in pumping losses account for the majority of the fuel consumption benefit associated with deactivating a cylinder. The main limitation in the employment of cylinder deactivation stems from the deterioration in the gross indicated thermal efficiency. Modelled results show that fuel consumption improvements are highest on low and part load operation envelopes. As such over the NEDC and FTP-75 benefits are in the range of 3.5%. Applying the technology over dynamically loaded cycles such as the WLTC and ARTEMIS, results in benefits of less than 1.6%. Further to modelling work on cylinder deactivation, experimental work has been carried out with the aim of allowing any engine size to be tested to cover transient drive cycles for future research. Future research could be in the aim of investigating technologies to reduce CO2 and emissions resulting from ICEs. Results show that the control solution implemented has allowed eddy-current dynamometers normally used for constant speed and brake load conditions to operate cycles such as the WLTC or any transient brake torque and engine speed pattern. Benchmark fuel consumption values for two engines of differing swept volume are within a 4g error band equivalent to a 0.36% and 0.67% percentage error band demonstrating the excellence of the control system.

High levels of soot-in-oil can cause an increase in engine wear and oil viscosity, thus reducing oil drain intervals. The mechanisms by which soot particles are entrained into the bulk oil are not well understood. The research reported in this thesis addresses questions on the mechanisms of soot transfer to the lubricating oil in light-duty diesel engines with high pressure EGR systems. Deposition as a result of blow-by gas passing the piston ring pack and by absorption to the oil film on the cylinder liner via thermophoresis are soot transfer mechanisms that have been considered in detail. The investigations are based on analytical and simulation studies, and results based on complementary experimental studies are used to validate these. The experimental investigations aimed at evaluating the typical rate of accumulation and size distribution of soot agglomerates in oil. The oil samples analysed were collected during regular services from light-duty diesel engine vehicles. These were representative of vehicles meeting Euro IV and V emission regulation standards driven under real-world conditions. The rate of soot-in-oil was determined by thermogravimetric analysis and results showed a concentration of approximately 1 wt% of soot-in-oil after 15,000 km. The particle size distribution was determined using a novel technique, Nanoparticle Tracking Analysis (NTA), applied for the first time to soot-laden oil samples by the author [1, 2]. Results showed an average particle size distribution of 150 nm, irrespective of oil drain interval. Almost the totality of the particles were between 70 and 400 nm, with micro particles not detected in any of the samples analysed. For the samples investigated in this work, the Euro standard did not influence either the rate of soot deposition or the particles size distribution. To the author’s best knowledge, this is the first time that rate of soot deposition and particles size distribution from oil samples collected from vehicles of different Euro standard driven under real-world conditions are analysed and compared. Exhaust Gas Recirculation (EGR) is a common technique used in diesel engines in order to reduce NO¬x emissions. However, it has the drawback that it increases the production of soot. In this work, particular attention has been given to its effects on the rate of soot deposition in oil. Both its influence on the soot produced during the combustion process and on the soot re-introduced in the combustion chamber by the EGR gas has been investigated through CFD simulations using Kiva-3V. Examining the relative importance of near–surface transport of soot by thermophoresis to the oil film on the liner and from blow-by gases to surfaces in the ring pack shows the former to be the dominant mechanism of soot transfer. EGR increases the rate of deposition of soot on the liner not only by increasing net production of soot, but also through the re-cycled particles. At EGR levels higher than 20%, the contribution of the Re-cycled soot becomes the major source for soot-in-oil. The study of soot deposition was evaluated during the entire engine cycle, including compression stroke and post-Exhaust Valve Opening (EVO) period. Existing deposition models found in the literature typically limit the domain to only from the Start of Injection (SOI) to (EVO) period [3-5]. Results from this thesis indicated that compression stroke and post-EVO period can contribute up to 30% of the total rate of soot deposition into oil.

Thesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2012. / Our planet is continuously being depleted of its natural resources leading to a need to conserve energy and the environment. One of the major energy consumers is the conventional internal combustion engine. Many attempts have been made to make these conventional internal combustion engines more efficient focusing mostly on the combustion side of the engine. The focus of this study is on the modification of the reciprocating and rotating components of the sub-assembly of a conventional internal combustion engine. An in-depth review was carried out on the fundamentals of spark ignition internal combustion engines and savings on fuel consumptions. A prototype single piston internal combustion engine was developed that can adjust its stroke length. Lengthening or shortening the stroke and simultaneously extending or retracting the connecting rod's travel distance, allows the internal combustion engine to function very efficiently consequently reducing the free space between the piston and cylinder head at TDC position. This allows the internal combustion engine to alter its power capability on demand whilst maintaining relatively high compression efficiency. The method of altering the stroke length is achieved by manipulating gears situated internally and externally of the engine sub-assembly. The control of these eccentric gears lowers or lifts the crankshaft in a radial motion. The eccentrics also control the automatic extension or retraction of the connecting rod's travel distance. The externally concentric gears control the mechanism that allows the internal combustion engine to change its capacity easily as adapted for automation. This study does not extend into the automation issues of the external mechanism. The prototype engine that was built could not endure vigorous testing and it failed after running for a short while. The primary focus had been on the kinematics of the engine mechanism - and to show whether the idea was feasible. The engine passed the kinematics test but failed possibly due to dynamic loads. Investigating this requires measuring instantaneous temperatures from which peak pressures can be deduced. This was not done because it was outside the scope of the project.

Orientador: Marco Lúcio Bittencourt / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-24T04:09:11Z (GMT). No. of bitstreams: 1 Rodrigues_AlexdeSouza_M.pdf: 4083435 bytes, checksum: d064f345587c31e235681e0db1417f27 (MD5) Previous issue date: 2013 / Resumo: Devido às atuais exigências de leis de emissão e redução de consumo de combustível, busca-se reduzir o peso dos componentes sem impacto aos critérios de projeto. Neste sentido, torna-se importante entender e discutir os critérios de projeto do componente em estudo. Este trabalho tem por objetivo entender a influência da redução do contrapeso de uma árvore de manivelas quatro cilindros em linha. Assim, para analisar o impacto da redução de massa nos contrapesos, foi realizado um estudo de sensibilidade nesta região do componente. Para analisar esta viabilidade, foram discutidos alguns critérios de balanceamento e a dinâmica do virabrequim em operação no motor. Nestas metodologias de balanceamento, resumiu-se a teoria básica mais comumente utilizada. Neste trabalho, aplicou-se o conjunto de ferramentas analisadas em um estudo de caso para um virabrequim forjado de um motor quatro cilindros em linha, obtendo-se a diferença dos critérios de balanceamento utilizados em relação à análise dinâmica. Foi observado que há critério de balanceamento que não considera efeito dinâmico importante. Finalmente, demonstrou-se que quando se deseja ter um contrapeso leve, existem alternativas de geometria que minimizam o impacto da retirada de massa / Abstract: Due to the current emission standard and fuel consumption requirements, lightweight components with no impact in the design criterion are desired. As a consequence, it is vital to understand and discuss the design criteria of the studied component. This work aims to understand the influence of crankshaft counterweight reduction in an inline-four cylinder engine. Thus, to analyze the counterweight mass reduction, it was done a sensitivity study at this region. In order to analyze this feasibility, it was discussed some balancing criteria and also the crankshaft under virtual engine operation. In these balancing methodologies, it was summarized the basic theory usually designed. In this work, it was applied a package of tools in a study of case for a 4cyl. in-line engine crankshaft, obtaining the difference between some balancing methods versus the dynamics analysis. It was noticed that there are balancing methodologies which do not mind important dynamics effect. All in all, it was showed that if a lightweight design is desired, there are some ways to minimize the unbalancing impact when saving counterweight mass / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

Orientadores: Pablo Siqueira Meirelles, Douglas E. Zampieri / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-04T03:09:14Z (GMT). No. of bitstreams: 1 Mendes_AlexandreSchalch_M.pdf: 7112696 bytes, checksum: 0f7bdbd014e6bd5c62865524aaa15fca (MD5) Previous issue date: 2005 / Resumo: Este trabalho tem como objetivo a análise do fenômeno das vibrações torcionais em árvores de manivelas de motores de combustão interna para aplicações veiculares. Como exemplo, a formulação proposta será aplicada no estudo da árvore de manivelas de um motor fabricado pela empresa MWM Motores Diesel Ltda., de seis cilindros em linha, quatro tempos, considerando-se a utilização de um amortecedor de vibrações de material elastomérico acoplado ao componente. Da análise das vibrações torcionais é possível de se obter os torques atuantes em cada secção do virabrequim. Estes esforços poderão ser aplicados posteriormente como condições de contorno a um modelo de elementos finitos, para que juntamente aos demais carregamentos existentes, seja feita a verificação do ciclo de fadiga atuante, de modo a avaliar o coeficiente de segurança do componente. Apesar de não ser este o foco deste trabalho, pode-se notar a importância da análise das vibrações torcionais no dimensionamento estrutural de uma árvore de manivelas. Iremos comparar as amplitudes de vibrações torcionais teóricas às obtidas experimentalmente, para a validação do modelo matemático proposto / Abstract: The scope of this work is the study of the crankshaft torsional vibration phenomenon for internal combustion engines. As an example, the formulation will be applied to an engine for a vehicular application, manufactured by MWM Motores Diesel Ltda., with six cylinders in line configuration, four strokes and considering a rubber damper assembled to the component. From the torsional vibrations analysis, it is possible to ca1culatethe actuating torque in each crankshaft section. These loads can be applied as boundary conditions to a finite element model and with the consideration of the other existing loads it is possible to determine the fatigue cyc1e,to calculate the safety factor ofthe component. This is not the objective ofthis work, but it is possible to note the importance of the torsional vibrations analysis in the structural dimensioning of the crankshafts. The obtained results by the presented methodology will be compared to the measured values for the validation of the proposed mathematical model / Mestrado / Mecanica dos Sólidos e Projeto Mecanico / Mestre em Engenharia Mecânica

Non-contact ignition of TIG welding arcs has been studied. The variation of dc voltage with dc current of combined acdc discharges indicated that an ac-dominated discharge, a dc-dominated discharge and a transition region exist during the initial current rise after breakdown from cold. These measurements enabled the conditions for reliable ignition of dc arcs using a continuous sinusoidal hf source to be predicted. The minimum current to sustain a cold arc and the time taken to reach the steady-state were investigated using a novel capacitor discharge supply. The results showed that to initiate a3 mm TIG welding arc from cold supplied by a power supply with an open circuit voltage of 80 V, a minimum current of about 0.9 A may be required and the time taken for the arc to reach the steady-state may take several hundred milliseconds. The results of investigations on combined ac-dc discharges, minimum current to sustain a cold arc and the time taken to reach the steady-state indicated that for safe, interference-free and reliable non-contact arc ignition, a continuous sinusoidal hf supply was the best method. A high voltage (about 3 kV) and high current (about 1 A) were required simultaneously to initiate a3 mm TIG arc from cold. A single continuous sinusoidal hf supply required an ignition power of the order of 1.35 kW which was not feasible. An arc ignition method using two continuous sinusoidal hf supplies has been devised which provides safe, interference-free and reliable arc ignition, and which requires less than 75% of the output power of a single continuous sinusoidal hf system. A solid-state hf ignition system based on the new method was designed and constructed.

Glow plugs are widely used to promote the desired cold start and post-cold start combustion characteristics of light duty diesel engines. The importance of the glow plug becomes more apparent when the compression ratio is low. An experimental investigation of combustion initiation and development aided by the glow plug has been carried out on a single cylinder HPCR DI diesel engine with a low compression ratio of 15.5:1. High speed imaging of combustion initiated by the glow plug in a combustion bomb has been used to add understanding of initiation process. Complementary CFD studies have been carried out using ANSYS Fluent 14.0 to explore the interactions between the glow plug and the spray behavior. Observation of successful combustion initiation show that two conditions must be met, compression heating and heat transfer from the glow plug must raise temperature of gas nearby to at least 413ºC and the vapour/air equivalence ratio no lower than 0.15-0.35. The initiation site was at spray edge close to the glow plug, the flame grew locally before expanding downstream in direction of spray penetration after the end of the main injection. Experimental studies carried out on the engine indicated that the engine IMEP, heat release and combustion stability were continuously improved by using the glow plug at ambient temperatures higher than the temperature requiring the glow plug for initiation of combustion. A rapid development of premixed combustion was achieved associated with improved engine work output, heat release rate and cycle-by-cycle stability. The premixed combustion was enhanced by strengthening spray vaporization through the glow plug. In this study, the combustion behavior was enhanced by the glow plug up to ambient temperature of 20ºC. Initiation delay was shortened by a rapid development of combustion aided by the glow plug. An initiation delay model was developed to account for both physical part (transport delay) and chemical part (chemical delay). The transport delay (ms) is equivalent to the time for spray to transport to the vicinity of the glow plug, dictated by parameters including S, distance between the glow plug tip and the injector tip (mm).

Internal diesel injector deposits (IDIDs) have become a prolific issue in the last decade, increased number of incidences have occurred since the introduction of ultra-low sulfur diesel and biodiesel. The IDIDs have caused concerns for customers such as injector systems misfiring or blocking, increased emissions and fuel consumption. Interest into the origins of the deposits has steadily grown, with identified possible causes including contaminants, degraded additives, or thermal and pressure stresses of the engine. Most examples in previous studies only provide surface analysis of IDIDs, however, the surface only provides a relatively small part of the story. In order to understand how an IDID has formed the history needs to be explained, to do this the lower layers of the IDID need to be analysed. Outcomes of this research include the first example of focused ion beam and secondary ion mass spectrometry being used in combination to analyse IDIDs and clearly shows different chemical layers, demonstrating that these deposits are made up of multiple complex chemistries. Raman spectroscopy can provide graphitic content information for IDIDs giving evidence of formation however, a method to remove fluorescence from carbonaceous structures was first devised and validated in order to allow this to be performed. The jet fuel thermal oxidation test (JFTOT) has been proven to be an effective method of replicating deposits on comparison with IDIDs from failed field engines, and key chemistries have been identified for B20 biodiesel and ultra-low sulfur diesel (ULSD). This work has used existing analytical methods to understand IDIDs and found novel insights that have not been previously observed in the literature.

The study of the reciprocating internal combustion engine is of prime importance to the student engineer. In our present civilization, the number of units and the total rated power of internal combustion engines in use is far greater than that of all other prime movers combined. Many basic engineering problems are present in the study of the operation of internal combustion engines. A number of mechanical and electrical devices have been developed to aid the engineer in his studies of engine performance. The purpose of this project is to provide the Mechanical Engineering Department of the North Dakota State University with an addition to its laboratory facilities which will enable the student to do additional experimental work in the internal combustion engines field. / North Dakota State University (NDSU)

No description available.