Premature Flame Initiation in a Turbocharged DISI Engine - Numerical and Experimental Investigations

The paper discusses the concept, design and final results from the 'Ultra Boost for Economy' collaborative project, which was part-funded by the Technology Strategy Board, the UK's innovation agency. The project comprised industry-and academiawide expertise to demonstrate that it is possible to reduce engine capacity by 60% and still achieve the torque curve of a modern, large-capacity naturally-aspirated engine, while encompassing the attributes necessary to employ such a concept in premium vehicles.In addition to achieving the torque curve of the Jaguar Land Rover naturally-aspirated 5.0 litre V8 engine (which included generating 25 bar BMEP at 1000 rpm), the main project target was to show that such a downsized engine could, in itself, provide a major proportion of a route towards a 35% reduction in vehicle tailpipe CO 2 on the New European Drive Cycle, together with some vehicle-based modifications and the assumption of stop-start technology being used instead of hybridization. In order to do this vehicle modelling was employed to set part-load operating points representative of a target vehicle and to provide weighting factors for those points. The engine was sized by using the fuel consumption improvement targets and a series of specification steps designed to ensure that the required full-load performance and driveability could be achieved.The engine was designed in parallel with 1-D modelling which helped to combine the various technology packages of the project, including the specification of an advanced charging system and the provision of the necessary variability in the valvetrain system. An advanced intake port was designed in order to ensure the necessary flow rate and the charge motion to provide fuel mixing and help suppress knock, and was subjected to a full transient CFD analysis. A new engine management system was provided which necessarily had to be capable of controlling many functions, including a supercharger engagement clutch and full bypass system, direct injection system, port-fuel injection system, separately-switchable cam profiles for the intake and exhaust valves and wide-range fast-acting camshaft phasing devices.

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“…The central DI arrangement doubtless also assisted this. All of this is in line with recent literature [25,26,27].…”

Section: Turner Et Al / Sae Int J Engines / Volume 7 Issue 1 (May supporting

confidence: 79%

Ultra Boost for Economy: Extending the Limits of Extreme Engine Downsizing

Turner

Popplewell

Patel

et al. 2014

SAE Int. J. Engines

147

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“…Higher volatility was confirmed to be helpful in terms of reducing the pre-ignition frequency in previous research [94,[100][101][102]. Chapman et al [100] demonstrated that preignition is well correlated with both T50 and T70 of the fuel.…”

Section: Fuel Propertiesmentioning

confidence: 84%

“…Another approach to limiting spray wetting is to adjust the injection timing and use split injection, which reduces the fuel-oil interactions by shortening the spray penetration [97,101,102]. Furthermore, optimizing the split injection timing and ratio for a double-injection strategy, Wang et al [103] effectively reduced the pre-ignition frequency.…”

Section: Engine Design Factors and Operational Parametersmentioning

confidence: 99%

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Recent Progress in Automotive Gasoline Direct Injection Engine Technology

Shuai

et al. 2018

Automot. Innov.

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Gasoline direct injection (GDI) engines are currently the dominant powertrains for passenger cars. With the implementation of increasingly stringent fuel consumption and emission regulations worldwide, GDI engines are facing challenges owing to high particulate matter emissions and a tendency to knock, leading to a change in the research and design (R&D) issues compared with those in the twentieth century. This paper reviews the progress in research regarding GDI engine technologies over the past 20 years, focusing on combustion system configurations, and also highlights common issues in GDI R&D, including preignition and deto-knock, soot formation and PM emissions, injector deposits and gasoline compression ignition (GCI). First, an overview of recent developments in the field as driven by regulations is provided, following which progress in injection and combustion systems is examined. Third, the review addresses the occurrence and mechanism of deto-knock and considers means of suppressing this phenomenon. The fourth section discusses soot formation mechanisms and particulate matter emission characteristics of GDI engines and describes the application of gasoline particulate filter (GPF) after-treatment. The subsequent section summarizes studies regarding injector deposit formation, as well as pioneering research into GCI combustion modes. Finally, a summary and future prospects for GDI engine technologies are provided.

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“…Due to the complicated molecular structure of these species with volatile and non-volatile components, there do not appear to be any accurate descriptions of the gas-phase chemistry of oil molecules [18]. As an alternative, an approach similar to that pursued by Maas et al [19] has been pursued in this work. Maas et al modeled the oil molecule as n-hexadecane whose physical properties are similar to that of lubricant oil.…”

Section: Oil Compositionmentioning

confidence: 99%

Effects of oil and water contamination on natural gas engine combustion processes

Menon

Ganti

Niemeyer

et al. 2017

Journal of Natural Gas Science and Engineering

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Abundant availability and potential for lower emissions are drivers for increased utilization of natural gas in automotive engines for transportation applications. A novel bimodal engine has been developed that allows on-board refueling of natural gas by utilizing the engine as a compressor. Engine compression however, results in altering the initial state of the natural gas. Increase in temperature and addition of oil are two key effects attributed to the onboard refueling process. A secondary effect is the presence of water in the natural gas supply line. This study investigates the effect of upstream conditions of natural gas on three parameters -autoignition temperature, ignition delay, and laminar flame speed. These parameters play key roles in the engine combustion process. Parametric studies are conducted by varying the initial mixture temperature, water, and oil content in the fuel. The studies utilize numerical simulations conducted with detailed chemistry for natural gas with n-heptane used as a surrogate for oil. Water addition to natural gas at 1-5% by volume did not result in any major changes in the combustion processes, other than a slight reduction in laminar flame speeds. Oil addition of 1-5% by volume reduced autoignition temperature by 5-10% and ignition delay by 27-95% depending on the initial temperature. Sensitivity analysis showed that this was likely due to decrease in the sensitivity of two recombination reactions with oil addition. Evolution profiles of key radical species also showed increasing mole fraction of the hydroperoxy radical at lower temperature that likely aids in reducing the ignition delay. Oil addition resulted in a relatively small increase in the laminar flame speed of 1.7% along with an increase in the adiabatic flame temperature. These results help inform the combustion process and performance to be expected from the bimodal engine.

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Premature Flame Initiation in a Turbocharged DISI Engine - Numerical and Experimental Investigations

Cited by 68 publications

References 13 publications

Ultra Boost for Economy: Extending the Limits of Extreme Engine Downsizing

Ultra Boost for Economy: Extending the Limits of Extreme Engine Downsizing

Recent Progress in Automotive Gasoline Direct Injection Engine Technology

Effects of oil and water contamination on natural gas engine combustion processes

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