Characterisation of flame development with ethanol, butanol, iso-octane, gasoline and methane in a direct-injection spark-ignition engine

Research into novel internal combustion engines requires consideration of the diversity in future fuels that may contain significant quantities of bio-components in an attempt to reduce CO2 emissions from vehicles and contribute to energy sustainability. However, most biofuels have different chemical and physical properties to those of typical hydrocarbons; these can lead to different mechanisms of mixture preparation and combustion. The current paper presents results from an optical study of combustion in a direct-injection spark-ignition research engine with gasoline, iso-octane, ethanol and butanol fuels injected from a centrally located multi-hole injector. Methane was also employed by injecting it into the inlet plenum of the engine to provide a benchmark case for well-mixed ‘homogeneous’ charge preparation. Crank-angle resolved flame chemiluminescence images were acquired and post-processed for a series of consecutive cycles for each fuel, in order to calculate in-cylinder rates of flame growth and motion. In-cylinder pressure traces were used for heat release analysis and for comparison with the image-processing results. All tests were performed at 1500 RPM with 0.5 bar intake plenum pressure. Stoichiometric (ϕ = 1.0) and lean (ϕ = 0.83) conditions were considered. The combustion characteristics were analysed with respect to laminar and turbulent burning velocities obtained from combustion bombs in the literature and from traditional combustion diagrams in order to bring all data into the context of current theories and allow insights by making comparisons were appropriate

An Analysis of the Combustion Behavior of Ethanol, Butanol, Iso-Octane, Gasoline, and Methane in a Direct-Injection Spark-Ignition Research Engine

Future automotive fuels are expected to contain significant quantities of bio-components. This poses a great challenge to the designers of novel low-CO2 internal combustion engines because biofuels have very different properties to those of most typical hydrocarbons. The current article presents results of firing a direct-injection spark-ignition optical research engine on ethanol and butanol and comparing those to data obtained with gasoline and iso-octane. A multihole injector, located centrally in the combustion chamber, was used with all fuels. Methane was also employed by injecting it into the inlet plenum to provide a benchmark case for well-mixed “homogeneous” charge preparation. The study covered stoichiometric and lean mixtures (λ = 1.0 and λ = 1.2), various spark advances (30–50° CA), a range of engine temperatures (20–90°C), and diverse injection strategies (single and “split” triple). In-cylinder gas sampling at the spark-plug location and at a location on the pent-roof wall was also carried out using a fast flame ionization detector to measure the equivalence ratio of the in-cylinder charge and identify the degree of stratification. Combustion imaging was performed through a full-bore optical piston to study the effect of injection strategy on late burning associated with fuel spray wall impingement. Combustion with single injection was fastest for ethanol throughout 20–90°C, but butanol and methane were just as fast at 90°C; iso-octane was the slowest and gasoline was between iso-octane and the alcohols. At 20°C, λ at the spark plug location was 0.96–1.09, with gasoline exhibiting the largest and iso-octane the lowest value. Ethanol showed the lowest degree of stratification and butanol the largest. At 90°C, stratification was lower for most fuels, with butanol showing the largest effect. The work output with triple injection was marginally higher for the alcohols and lower for iso-octane and gasoline (than with single injection), but combustion stability was worse for all fuels. Triple injection produced a lower degree of stratification, with leaner λ at the spark plug than single injection. Combustion imaging showed much less luminous late burning with tripe injection. In terms of combustion stability, the alcohols were more robust to changes in fueling (λ = 1.2) than the liquid hydrocarbons

Imaging and heat flux measurements of wall impinging sprays of hydrocarbons and alcohols in a direct-injection spark-ignition engine

The latest generation of fuel systems for direct-injection spark-ignition engines uses injection nozzles that accommodate a number of holes with various angles in order to offer flexibility in in-cylinder fuel targeting over a range of engine operating conditions. However, the high-injection pressures that are needed for efficient fuel atomisation can lead to deteriorating effects with regards to engine exhaust emissions (e.g. unburned hydrocarbons and particulates) from liquid fuel impingement onto the piston and liner walls. Eliminating such deteriorating effects requires fundamental understanding of in-cylinder spray development processes, taking also into account the diversity of future commercial fuels that can contain significant quantities of bio-components with very different chemical and physical properties to those of typical liquid hydrocarbons. This paper presents high-speed imaging results of spray impingement onto the liner of a direct-injection spark-ignition engine, as well as crank-angle resolved wall heat flux measurements at the observed locations of fuel impingement for detailed characterisation of levels and timing of impingement. The tests were performed in a running engine at 1500 RPM primarily at low load (0.5 bar intake pressure) using 20, 50 and 90 °C engine temperatures. Gasoline, iso-Octane, Butanol, Ethanol and a blend of 10% Ethanol with 90% Gasoline (E10) were used to encompass a range of current and future fuel components for spark-ignition engines. The collected data were analysed to extract mean and standard deviation statistics of spray images and heat flux signals. The results were also interpreted with reference to physical pro

Plumbers Graduate

Hubert Joe; Greg Lee; Bob Irvine. Capilano College was among the first, if not the first, to offer vocational programs in small First Nations locations. Many students from Mt Currie were hired to build the "new" Whistler village. Selected by 50th Anniversary History Team

Spray Development, Flow Interactions and Wall Impingement in a Direct-Injection Spark-Ignition Engine

Levels of liquid fuel impingement on in-cylinder surfaces in direct injection spark ignition engines have typically been higher than those in port-fuel injection engines due to in-cylinder injection and higher injection pressures. The result is typically an increase in the levels of un-burned hydrocarbons and smoke emissions which reduce the potential fuel economy benefits associated with direct injection engines. Although different injection strategies can be used to reduce these effects to some extent, full optimisation of the injection system and combustion process is only possible through improved understanding of spray development that can be obtained from optical engine investigations under realistic operating conditions. To this extent, the spray formation from a centrally mounted multi-hole injector was studied in a single-cylinder optical direct-injection spark-ignition engine under part-load conditions (0.5 bar intake plenum pressure) at 1500 RPM. A high-speed camera and laser illumination were used to obtain Mie-scattering images of the spray development on different in-cylinder planes for a series of consecutive engine cycles. The engine temperature was varied to reflect cold-start (20 °C) and fully warm (90 °C) engine conditions. A multi-component fuel (commercial gasoline) and a single-component fuel (iso-octane) were both tested and compared to investigate the effects of fuel properties on spray formation and wall impingement. An experimental arrangement was also developed to detect in-cylinder liquid fuel impingement using heat flux sensors installed on the cylinder liner. Two different injection strategies were tested; a typical single-injection strategy in the intake stroke to promote homogeneous mixture formation, as well as a triple-injection strategy around the same timing to assess the viability of using multiple-injection strategies to reduce wall impingement and improve mixture preparation. A sweep of different locations around the cylinder bore revealed the locations of highest fuel impingement levels which did not correspond directly to the nominal spray plume trajectories as a result of spray-flow interactions. These results were analysed in conjunction with the observed effects from the parallel imaging investigation. Copyright © 2007 SAE International

Fibrose quistica : como chegamos à idade adulta

Copyright © 2019 Sociedade Portuguesa de Pneumologia. Published by Elsevier España, S.L.U. This is an open access article under the CCBY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)info:eu-repo/semantics/publishedVersio

Central Retinal Artery Occlusion from Streptococcus Gallolyticus Endocarditis

Central retinal artery occlusion (CRAO) is a rare but blinding disorder. We present a case of a 81-year-old woman with multiple cardiovascular comorbidities admitted to the emergency department due to sudden, painless vision loss on left eye (oculus sinister (OS)) on awakening. The patient also reported long standing fatigue associated with effort that started 4 months before admission. She presented best corrected visual acuity of counting fingers OS. Funduscopy OS revealed macular oedema with cherry red spot pattern. Blood cultures came positive for Streptococcus gallolyticus in the context of a bacteremia and native mitral valve vegetation identified on transoesophageal echocardiography. CRAO of embolic origin was admitted in the context of an infective endocarditis. CRAO can be the first manifestation of a potentially fatal systemic condition and thus multidisciplinary approach is warranted with close collaboration between ophthalmologists and internists in order to provide proper management and the best possible treatment.info:eu-repo/semantics/publishedVersio