Fundamental Approach to Investigate Pre-Ignition in Boosted SI Engines

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

145

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“…One suggestion has been that fuel droplets from the injecting spray impinge on the cylinder wall and mix with lubricating oil and mixture droplets moving in to the gas phase [41,42]. Long-chain molecules from the lubricant with its additives are sufficiently auto-ignitive to create mild auto-ignitions that can, nevertheless, initiate a flame [39].…”

Section: Engine Performance and The Detonation Peninsulamentioning

confidence: 99%

Engine hot spots: Modes of auto-ignition and reaction propagation

Bates

Bradley

Paczko

et al. 2016

Combustion and Flame

112

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expresses the influences of hot spot temperature gradient and fuel characteristics, and a unique value of it might serve as a boundary between auto-ignitive and deflagrative regimes. Other combustion regimes can also be identified, including a mixed regime of both auto-ignitive and "normal" 2 deflagrative burning. The paper explores the performances of a number of different engines in the regimes of controlled auto-ignition, normal combustion, combustion with mild knock and, ultimately, super-knock. The possible origins of hot spots are discussed and it is shown that the dissipation of turbulent energy alone is unlikely to lead directly to sufficiently energetic hot pots. The knocking characterisation of fuels also is discussed.

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“…Figure 1 shows the typical configurations of side-mounted and central-mounted injectors. Other investigations [17][18][19] have shown that, compared with central-mounted injectors, side-mounted injectors exhibit better performance in terms of enhanced tumble motion, thermal load reduction, preignition suppression and thermal efficiency improvement. However, it is more difficult for a side-mounted injector to realize spray-guided operation due to the potential for impingement.…”

Section: Development Of Gdi Combustion Systemsmentioning

confidence: 99%

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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Fundamental Approach to Investigate Pre-Ignition in Boosted SI Engines

Cited by 177 publications

References 8 publications

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

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

Engine hot spots: Modes of auto-ignition and reaction propagation

Recent Progress in Automotive Gasoline Direct Injection Engine Technology

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