In-Cylinder Combustion Visualization in an Auto-Igniting Gasoline Engine using Fuel Tracer- and Formaldehyde-LIF Imaging

Graf, Nicole; Gronki, Joachim; Schulz, Christof; Baritaud, T.; Cherel, J.; Duret, Pierre; Lavy, Jacques

doi:10.4271/2001-01-1924

Cited by 49 publications

(22 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…With varying levels of complexity of both equipment and technique, they have been applied extensively by many researchers in SI and CI engines for a long period of time [11,12]. For CAI, many researchers have successfully applied PLIF techniques to capture fluorescence of OH and formaldehyde to analyse the autoignition and combustion process [13][14][15]. Application of simpler techniques which do not rely on laser illumination and doped fuels for imaging combustion can allow for more realistic engine conditions.…”

Section: Introductionmentioning

confidence: 99%

Combustion Characteristics of CAI Combustion with Alcohol Fuels

Tongroon

Zhao

2010

SAE Technical Paper Series

View full text Add to dashboard Cite

Due to its potential for simultaneous improvement in fuel consumption and exhaust emissions, controlled autoignition (CAI) combustion has been subject to continuous research in the last several years. At the same time, there has been a lot of interest in the use of alternative fuels in order to reduce reliance on conventional fossil fuels. Therefore, this experimental study has been carried out to investigate the effect of alcohol fuels on the CAI combustion process and on the resulting engine performance.The experimental work was conducted on an optical single cylinder engine with an air-assisted injector. To achieve controlled autoignition, residual gas was trapped in the cylinder by using negative valve overlap and an intake air heater was used to ensure stable CAI combustion in the optical engine. Methanol, ethanol and blended fuels were tested and compared with the results of gasoline. The combustion processes were analysed through total chemiluminescence images captured with a high speed camera equipped with an intensifier. In addition, the effect of spark discharge was investigated.The images show that CAI combustion of alcohol fuels was characterized with fast and early autoignition combustion compared with pure gasoline. Chemiluminescence of the gasoline fuel was most visible and it decreased with increasing percentage of oxygenated fuels. During the re-compression stroke, chemiluminescence images of the gasoline engine indicated the presence of oxidation reactions. In the presence of spark discharge, the location of charge ignition was dominated by spark discharge at the center of cylinder while simultaneous autoignition sites were found around the periphery of the combustion chamber for nonspark-assisted ignition.

show abstract

Section: Introductionmentioning

confidence: 99%

Combustion Characteristics of CAI Combustion with Alcohol Fuels

Tongroon

Zhao

2010

SAE Technical Paper Series

View full text Add to dashboard Cite

show abstract

“…Hultqvist et al [82] showed cool-flame emission spectra from iso-octane/nheptane HCCI combustion and discussed that these spectra originated from the presence of formaldehyde (HCHO). LIF studies have shown how HCHO and OH species are present within the 'cool' flame period and subsequent 'hot' combustion [84][85][86]. The absence of carbon atoms, and thus HCHO, from the in-cylinder mixture of a hydrogen HCCI engine means that a totally different mechanism of autoignition is in operation and that OH generation would be very different from that of hydrocarbon fuels.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen SI and HCCI Combustion in a Direct-Injection Optical Engine

Rosati¹,

Aleiferis²

2009

SAE Int. J. Engines

View full text Add to dashboard Cite

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 ABSTRACTHydrogen has been largely proposed as a possible alternative fuel for internal combustion engines. Its wide flammability range allows higher engine efficiency with leaner operation than conventional fuels, for both reduced toxic emissions and no CO 2 gases. Independently, Homogenous Charge Compression Ignition (HCCI) also allows higher thermal efficiency and lower fuel consumption with reduced NO X emissions when compared to Spark-Ignition (SI) engine operation. For HCCI combustion, a mixture of air and fuel is supplied to the cylinder and autoignition occurs from compression; engine is operated throttle-less and load is controlled by the quality of the mixture, avoiding the large fluid-dynamic losses in the intake manifold of SI engines. HCCI can be induced and controlled by varying the mixture temperature, either by Exhaust Gas Recirculation (EGR) or intake air pre-heating. A combination of HCCI combustion with hydrogen fuelling has great potential for virtually zero CO 2 and NO X emissions. Nevertheless, combustion on such a fast burning fuel with wide flammability limits and high octane number implies many disadvantages, such as control of backfiring and speed of autoignition and there is almost no literature on the subject, particularly in optical engines. Experiments were conducted in a singlecylinder research engine equipped with both Port Fuel Injection (PFI) and Direct Injection (DI) systems running at 1000 RPM. Optical access to in-cylinder phenomena was enabled through an extended piston and optical crown. Combustion images were acquired by a highspeed camera at 1° or 2° crank angle resolution for a series of engine cycles. Spark-ignition tests were initially carried out to benchmark the operation of the engine with hydrogen against gasoline. DI of hydrogen after intake valve closure was found to be preferable in order to overcome problems related to backfiring and air displacement from hydrogen's low density. HCCI combustion of hydrogen was initially enabled by means of a pilot port injection of n-heptane preceding the main direct injection of hydrogen, along with intake air preheating. Sole hydrogen fuelling HCCI was finally achieved and made sustainable, even at the low compression ratio of the optical engine by means of closed-valve DI, in synergy with air-pre-heating and negative valve overlap to promote intern...

show abstract

“…Hence, formaldehyde is an indicator of the first stage of ignition and a marker for zones with low temperature reactions. Planar laser induced fluorescence from formaldehyde has been used earlier for visualization of self-ignition centres in SI-engines [6], for studying the ignition of Diesel sprays [7] and for characterization of the Controlled Auto Ignition (CAI) combustion concept [8].…”

Section: Introductionmentioning

confidence: 99%

Simultaneous OH- and Formaldehyde-LIF Measurements in an HCCI Engine

Collin¹,

Nygren²,

Richter³

et al. 2003

SAE Technical Paper Series

View full text Add to dashboard Cite

Simultaneous OH-and formaldehyde LIF measurements have been performed in an HCCI engine using two laser sources working on 283 and 355 nm, respectively. Two ICCD camera systems, equipped with long-pass filters, were used to collect the LIF signals. The simultaneous images of OH and formaldehyde were compared with heat-release calculated from the pressure-trace matching the cycle for the LIF measurements.The measurements were performed on a 0.5 l singlecylinder optical engine equipped with port-fuel injection system. A blend of iso-octane and n-heptane was used as fuel and the compression ratio was set to 12:1. The width of the laser sheet was 40 mm and hence covered approximately half of the cylinder bore.At some 20 CAD BTDC low temperature reactions is present and formaldehyde is formed. The formaldehyde signal is then rather constant until the main heat-release starts just before TDC, where the signal decreases rapidly to low values. From some 15 CAD to 5 CAD BTDC the formaldehyde is uniformly distributed in the imaged area. As formaldehyde decreases, OH increases and follows the main rate of heat release curve, though with a slight lag in phase. Thereafter OH is formed in the areas from which the formaldehyde has disappeared and the OH signal is present to some 20 CAD ATDC.

show abstract

In-Cylinder Combustion Visualization in an Auto-Igniting Gasoline Engine using Fuel Tracer- and Formaldehyde-LIF Imaging

Cited by 49 publications

References 13 publications

Combustion Characteristics of CAI Combustion with Alcohol Fuels

Combustion Characteristics of CAI Combustion with Alcohol Fuels

Hydrogen SI and HCCI Combustion in a Direct-Injection Optical Engine

Simultaneous OH- and Formaldehyde-LIF Measurements in an HCCI Engine

Contact Info

Product

Resources

About