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Visual Analyses of End of Injection Liquid Structures and the Behaviour of Nozzle Surface-Bound Fuel in a Direct Injection Diesel Engine

BP International Ltd.-Martin Gold, Richard Pearson
University of Brighton-Dan Sykes, Guillaume de Sercey, Cyril Crua
Published 2019-01-15 by SAE International in United States
For efficiency, the majority of modern diesel engines implement multiple injection strategies, increasing the frequency of transient injection phases and thus, end of injection (EOI) events. Recent advances in diagnostic techniques have identified several EOI phenomena pertinent to nozzle surface wetting as a precursor for deposit formation and a potential contributor towards pollutant emissions. To investigate the underlying processes, highspeed optical measurements at the microscopic scale were performed inside a motored diesel engine under low load/idling conditions. Visualisation of the injector nozzle surface and near nozzle region permitted an indepth analysis of the post-injection phenomena and the behaviour of fuel films on the nozzle surface when the engine is not fired. Inspection of the high-speed video data enabled an interpretation of the fluid dynamics leading to surface wetting, elucidating the mechanisms of deposition and spreading. As the needle re-seated, the abrupt pressure drop inhibited atomisation. Large, slow moving, liquid structures were released into the cylinder with the capability of impinging on nearby surfaces, creating localised fuel rich regions, or escaping through the exhaust and contributing…
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Fast NGC: A New On-Line Technique for Fuel Flow Measurement

BP International Ltd.-Martin Gold, Richard Pearson
University of Oxford-Felix Leach, Martin Davy, Manus Henry, Maruthi Rochishnu Malladi, Michael Tombs, Feibiao Zhou
Published 2019-01-15 by SAE International in United States
Knowledge of fuel mass injected in an individual cycle is important for engine performance and modelling. Currently direct measurements of fuel flow to individual cylinders of an engine are not possible on-engine or in real-time due to a lack of available appropriate measurement techniques. The objective of this work was to undertake real-time Coriolis fuel flow measurement using GDI injectors on a rig observing fuel mass flow rate within individual fuel injections. This paper evaluates the potential of this technology - combining Coriolis Flow Meters (CFMs) with Prism signal processing together known as Fast Next Generation Coriolis (Fast NGC), and serves as a basis for future transitions on-engine applications. A rig-based feasibility study has been undertaken injecting gasoline through a GDI injector at 150 bar in both single shot mode and at a simulated engine speeds of 1788 and 2978 rpm. The results show that these injections can, in principle, be observed. In addition a number of features of the Fast NGC system unique to gasoline are discussed, and the repeatability of the technique is preliminarily assessed.…
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Simulation and Measurement of Transient Fluid Phenomena within Diesel Injection

SAE International Journal of Advances and Current Practices in Mobility

BP International Ltd.-Martin Gold, Richard Pearson
City University London-Mithun Murali-Girija, Foivos Koukouvinis, Manolis Gavaises
  • Journal Article
  • 2019-01-0066
Published 2019-01-15 by SAE International in United States
Rail pressures of modern diesel fuel injection systems have increased significantly over recent years, greatly improving atomisation of the main fuel injection event and air utilisation of the combustion process. Continued improvement in controlling the process of introducing fuel into the cylinder has led to focussing on fluid phenomena related to transient response. High-speed microscopy has been employed to visualise the detailed fluid dynamics around the near nozzle region of an automotive diesel fuel injector, during the opening, closing and post injection events. Complementary computational fluid dynamic (CFD) simulations have been undertaken to elucidate the interaction of the liquid and gas phases during these highly transient events, including an assessment of close-coupled injections.Microscopic imaging shows the development of a plug flow in the initial stages of injection, with rapid transition into a primary breakup regime, transitioning to a finely atomised spray and subsequent vaporisation of the fuel. During closuring of the injector the spray collapses, with evidence of swirling breakup structures together with unstable ligaments of fuel breaking into large slow-moving droplets. This leads to…
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Reduction of CO2 Emissions through Lubricant Thermal Management During the Warm Up of Passenger Car Engines

BP International Ltd.-Richard Pearson
BP International Ltd., Univ. of Oxford-Oliver P. Taylor
Published 2016-04-05 by SAE International in United States
Most major regional automotive markets have stringent legislative targets for vehicle greenhouse gas emissions or fuel economy enforced by fiscal penalties. Large improvements in vehicle efficiency on mandated test cycles have already taken place in some markets through the widespread adoption of technologies such as downsizing or dieselisation. There is now increased focus on approaches which give smaller, but significant incremental efficiency benefits, such as reducing parasitic losses due to engine friction.The reduction in tail pipe CO2 emissions through the reduction of engine friction using lubricants has been reported by many authors. However, opportunities also exist to reduce the lubricant viscosity during warm up by the thermal management of the lubricant mass. This presents an attractive proposition to vehicle manufacturers because of the favorable cost-benefit ratios of thermal management systems and because this strategy can achieve some of the benefits that ordinarily require the lubricant viscosity grade to be lowered.In this paper the experimental results from chassis dynamometer tests are analysed. The performance of two modern vehicles was determined using various lubricant thermal management strategies,…
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CO2 Emission Reduction Synergies of Advanced Engine Design and Fuel Octane Number

BP International Ltd.-Ben Leach, Richard Pearson, Rana Ali, John Williams
Published 2014-10-13 by SAE International in United States
Engine downsizing is a key approach employed by many vehicle manufacturers to help meet fleet average CO2 emissions targets. With gasoline engines in particular reducing engine swept volume while increasing specific output via technologies such as turbocharging, direct injection (DI) and variable valve timing can significantly reduce frictional and pumping losses in engine operating areas commonly encountered in legislative drive cycles.These engines have increased susceptibility to abnormal combustion phenomena such as knock due to the high brake mean effective pressures which they generate. This ultimately limits fuel efficiency benefits by demanding use of a lower geometric compression ratio and sub-optimal late combustion phasing at the higher specific loads experienced by these engines. The lower expansion ratio and retarded combustion in turn increase the exhaust gas temperature, which often leads to a need to add extra fuel that cannot be fully combusted in order to cool and protect engine components from thermal damage. Optimizing the engine design for use with a fuel with an increased research octane number (RON) allows the adoption of a higher compression…
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Engine Lubrication and Cooling During Hybrid Vehicle Operation

BP International, Ltd.-Ben Leach, Richard Pearson
Published 2014-10-13 by SAE International in United States
Rising fuel prices and changes to CO2 and fuel economy legislation have prompted an interest in the electrification of vehicles since this can significantly improve vehicle tailpipe CO2 emissions over homologation test cycles. To this end plug-in hybrid electric vehicles (PHEVs) and range extended electric vehicles (REEVs) have been introduced to the market. The operation of the engines in these vehicles differs from conventional vehicles in several key ways. This study was conducted to better understand how the engine design and control strategy of these vehicles affects the temperature and operating regimes experienced by engine crankcase lubricants.A Toyota Prius Plug-in PHEV and GM Volt REEV were tested on a chassis dynamometer over several legislated and pseudo ‘real world’ drive cycles to determine the operating strategy and behaviour of the powertrain. The lubricant and coolant temperatures were monitored, together with other key control parameters. Tests were completed with both hot and cold engine starts at 25°C and −7°C test cell temperatures in charge-depleting and charge-sustaining operating modes.The key findings for both vehicles were: The vehicles operate…
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Tribological Behavior of Low Viscosity Lubricants in the Piston to Bore Zone of a Modern Spark Ignition Engine

BP International Ltd.-Richard Pearson
BP International Ltd. / University of Oxford-Oliver P. Taylor
Published 2014-10-13 by SAE International in United States
Most major regional automotive markets have stringent legislative targets for vehicle greenhouse gas emissions or fuel economy enforced by fiscal penalties. Large improvements in vehicle efficiency on mandated test cycles have already taken place in some markets through the widespread adoption of technologies such as downsizing or dieselization. There is now increased focus on approaches which give smaller but significant incremental efficiency benefits such as reducing parasitic losses due to engine friction. Fuel economy improvements which achieve this through the development of advanced engine lubricants are very attractive to vehicle manufacturers due to their favorable cost-benefit ratio.For an engine with components which operate predominantly in the hydrodynamic lubrication regime, the most significant lubricant parameter which can be changed to improve the tribological performance of the system is the lubricant viscosity. Low viscosity lubricants are increasingly being specified by vehicle manufacturers who are now more frequently working directly with the lubricant supplier to design fluids specific to their requirements. As lubricant viscosity grades far below those currently in the market are investigated it is vital that…
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Drive Cycle Analysis of Load Control Strategies for Methanol Fuelled ICE Vehicle

Ghent University-Kaname Naganuma, Jeroen Vancoillie, Louis Sileghem, Sebastian Verhelst
Karel De Grote-Hogeschool-Kris Martens
Published 2012-09-10 by SAE International in United States
The use of methanol as spark-ignition engine fuel can help to increase energy security and offers the prospect of carbon neutral transport. Methanol's properties enable considerable improvements in engine performance, efficiency and CO2 emissions compared to gasoline operation. SAE paper 2012-01-1283 showed that both flex-fuel and dedicated methanol engines can benefit from an operating strategy employing exhaust gas recirculation (EGR) to control the load while leaving the throttle wide open (WOT). Compared to throttled stoichiometric operation, this reduces pumping work, cooling losses, dissociation and engine-out NOx.The current paper presents follow-up work to determine to what extent these advantages still stand over an entire drive cycle. The average vehicle efficiency, overall CO2 and NOx emissions from a flexible fuel vehicle completing a drive cycle on gasoline and methanol were evaluated. Next, the throttled and WOT EGR strategy were compared in terms of drive cycle efficiency and emissions for both a flex-fuel and a dedicated methanol vehicle. The analysis was done using Lotus Vehicle Simulation and was based on steady state experimental results obtained from a single…
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GEM Ternary Blends: Removing the Biomass Limit by using Iso-Stoichiometric Mixtures of Gasoline, Ethanol and Methanol

BioMCN-Eelco Dekker
Lotus Engineering-James Turner, Richard Pearson, Ralph Purvis
Published 2011-09-11 by SAE International in United States
The paper presents the concept of ternary blends of gasoline, ethanol and methanol in which the stoichiometric air-fuel ratio (AFR) is controlled to be 9.7:1, the same as that of conventional ‘E85’ alcohol-based fuel. This makes them iso-stoichiometric. Such blends are termed ‘GEM’ after the first initial of the three components. Calculated data is presented showing how the volumetric energy density relationship between the three components in these blends changes as the stoichiometric AFR is held constant but ethanol content is varied. From this data it is contended that such GEM blends can be ‘drop-in’ alternatives to E85, because when an engine is operated on any of these blends the pulse widths of the fuel injectors would not change significantly, and so there will be no impact on the on-board diagnostics from the use of such blends in existing E85/gasoline flex-fuel vehicles. The resulting ability of such blends to extend the reach of a fixed amount of ethanol in the fuel pool is then demonstrated, together with the mechanism by which the addition of the…
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The Lotus Range Extender Engine

SAE International Journal of Engines

Lotus Engineering-James Turner, Darren Blake, Jason Moore , Paul Burke , Richard Pearson, Rishin Patel, Dave Blundell, Rashmesh Chandrashekar , Luigi Matteucci, Phil Barker , Clive Card
  • Journal Article
  • 2010-01-2208
Published 2010-10-25 by SAE International in United States
The paper discusses the concept, specification and performance of a new, dedicated range extender engine for plug-in series hybrid vehicles conceived and designed by Lotus Engineering. This has been undertaken as part of a consortium project called Limo Green, part-funded by the UK government.The Lotus Range Extender engine has been conceived from the outset specifically as an engine for a plug-in series hybrid vehicle, therefore being free of some of the constraints placed on engines which have to mate to conventional, stepped mechanical transmissions. The paper starts by defining the philosophical difference between an engine for range extension and an engine for a full series hybrid vehicle, a distinction which is important with regard to how much power each type must produce. As part of this, the advantages of the sparkignition engine over the diesel are outlined. The rationale leading to the adoption of an in-line 3-cylinder configuration and specification is then discussed, followed by a description of the principal design characteristics of the engine; it also points out any significant differences from what might…
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