Analysis of Different Gasoline Combustion Concepts with Focus on Gas Exchange

Sauer, Christina; Kulzer, André; Rauscher, Martin; Hettinger, Alexander

doi:10.4271/2008-01-0427

Cited by 6 publications

(4 citation statements)

References 6 publications

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“…At one end of the spectrum, various electro-magnetic and electro-hydraulic systems have been proposed. Such camless systems have been reported to allow the greatest potential for reduction in SI engine breathing losses (10,11) and/or can be used to realize advanced modes of operation such as Controlled Auto Ignition (12,13). However, in general these systems often still have significant issues to overcome including packaging, noise and cost.…”

Section: Introductionmentioning

confidence: 99%

Combining Unthrottled Operation with Internal EGR under Port and Central Direct Fuel Injection Conditions in a Single Cylinder SI Engine

Cairns¹,

Todd²,

Hoffman³

et al. 2009

SAE Technical Paper Series

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The Engineering Meetings Board has approved this paper for publication. It has successfully completed SAE's peer review process under the supervision of the session organizer. This process requires a minimum of three (3) reviews by industry experts. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. ISSN 0148-7191 Positions and opinions advanced in this paper are those of the author(s) and not necessarily those of SAE. The author is solely responsible for the content of the paper. SAE ABSTRACTThis experimental work was concerned with the combination of internal EGR with an early inlet valve closure strategy for improved part-load fuel economy. The experiments were performed in a new spark-ignited thermodynamic single cylinder research engine, equipped with a mechanical fully variable valvetrain on both the inlet and exhaust. During unthrottled operation at constant engine speed and load, increasing the mass of trapped residual allowed increased valve duration and lift to be used. In turn, this enabled further small improvements in gas exchange efficiency, thermal efficiency and hence indicated fuel consumption. Such effects were quantified under both port and homogeneous central direct fuel injection conditions. Shrouding of the inlet ports as a potential method to increase in-cylinder gas velocities has also been considered.

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Section: Introductionmentioning

confidence: 99%

Combining Unthrottled Operation with Internal EGR under Port and Central Direct Fuel Injection Conditions in a Single Cylinder SI Engine

Cairns¹,

Todd²,

Hoffman³

et al. 2009

SAE Technical Paper Series

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“…An important aspect of the gas exchange process involves pumping work that is calculated by integrating the cylinder pressure with respect to cylinder volume calculated from bottom dead centre (BDC) of the exhaust stroke to BDC of the intake stroke. 14 Pumping work can influence engine performance in several aspects, including the relationship between BMEP, net/ gross indicated mean effective pressure (IMEP) and friction mean effective pressure (FMEP) as shown in equations (2) and (3)…”

Section: Downsized Turbocharged Si Engine Only At the Research Stagementioning

confidence: 99%

“…43 Chadwell et al 20 stated that the stratified charge, which is one of the lean concepts, can benefit from better pumping work under the lean limit due to de-throttling. Saucer et al 14 demonstrated that the stratified charge had a better cycle efficiency due to the lower mean temperature because of dilution.…”

Section: Strategies For Optimizing the Gas Exchange Processmentioning

confidence: 99%

Novel approaches to improve the gas exchange process of downsized turbocharged spark-ignition engines: A review

Akehurst

Brace

2015

International Journal of Engine Research

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Engine downsizing, which is the use of a smaller engine that provides the power of a larger engine, is now considered a mega-trend for the internal combustion engine market. It is usually achieved using one or more boosting devices including a supercharger or a turbocharger. Although supercharging is beneficial for engine's transient response, turbocharging technology is more widely adopted considering its advantages in fuel efficiency. Compared to turbocharged compression ignition engines, turbocharged spark-ignition engines tend to be more challenging with respect to the gas exchange process mainly due to their higher pumping loss, the need for throttling and the fact that spark-ignition engines demand more controllability due to the mitigation of knock, particularly with regard to minimizing trapped residuals. These challenges encourage the entire gas exchange process of turbocharged spark-ignition engines to be regarded as a complete air management system instead of just looking at the boosting system in isolation. In addition, more research emphasis should be focused on novel approaches to improve the gas exchange process of downsized turbocharged spark-ignition engines because the refinement of the conventional technologies cannot provide continuous gains indefinitely and only innovative concept may improve the engine performance to meet the fuel efficiency target and the more stringent emission regulation in the future. This article will first briefly review knowledge of the current state of the art technologies that are in production as opposed to approaches that are currently only being investigated at a research level. Next, more novel methods of the gas exchange process are introduced to identify the improved synergies between the engine and the boosting machine. The major findings to improve the gas exchange process that emerge from this review comprise four aspects (depending on the location where the novel technologies are implemented) which are as follows: charge air pressurization/de-pressurization improvement, combustion efficiency enhancement within the chamber, valve event-associated development and exhaust system optimization. Although the interaction between these technologies on different aspects of the gas exchange process was found to be highly complex, the optimization or the combination of these technologies is anticipated to further improve a downsized turbocharged spark-ignition engine's performance.

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“…At one end of the spectrum, various electro-magnetic and electro-hydraulic systems have been proposed. Such camless systems have been reported to allow the greatest potential for reduction in SI engine breathing losses (9,10) and/or can be used to realize advanced modes of operation such as Controlled Auto Ignition (11,12). However, in general these systems often still have significant issues to overcome including packaging, noise and cost.…”

Section: Introductionmentioning

confidence: 99%

A Study of Alcohol Blended Fuels in an Unthrottled Single Cylinder Spark Ignition Engine

Cairns¹,

Todd²,

Aleiferis³

et al. 2010

SAE Technical Paper Series

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This work involved study of the effects of alcohol blends on combustion, fuel economy and emissions in a single cylinder research engine equipped with a mechanical fully variable valvetrain on the inlet and variable valve timing on the exhaust. A number of splash blends of gasoline, iso-octane, ethanol and butanol were examined during port fuel injected early inlet valve closing operation, both with and without variable valve timing. Under low valve overlap conditions, it was apparent that the inlet valve durations/lifts required for full unthrottled operation were remarkably similar for the wide range of blends studied. However, with high valve overlap differences in burning velocities and internal EGR tolerances warranted changes in these valve settings. In turn, it was concluded that high ethanol content blends facilitated minimum throttling at the inlet valve itself and the largest relative savings in terms of fuel consumption, engine-out emissions of NOx and (corrected) unburned hydrocarbons.

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Analysis of Different Gasoline Combustion Concepts with Focus on Gas Exchange

Cited by 6 publications

References 6 publications

Combining Unthrottled Operation with Internal EGR under Port and Central Direct Fuel Injection Conditions in a Single Cylinder SI Engine

Combining Unthrottled Operation with Internal EGR under Port and Central Direct Fuel Injection Conditions in a Single Cylinder SI Engine

Novel approaches to improve the gas exchange process of downsized turbocharged spark-ignition engines: A review

A Study of Alcohol Blended Fuels in an Unthrottled Single Cylinder Spark Ignition Engine

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