Abnormal Combustion in a Methanol Fueled Engine

Swain, M.R.; Blanco, Jorge; Swain, Matthew N.

doi:10.4271/892162

Cited by 5 publications

(2 citation statements)

References 6 publications

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“…It is established that catalytic reactions can enhance pre-ignitions at surfaces, with and without deposits. 6,7,9 It is possible that catalysis is also important for fuel–oil droplet reactions at hot spots. In Zadeh et al, 2 the use of an oil with few additives, particularly those based on calcium and barium, seemed to eradicate previous sporadic gas-phase pre-ignitions.…”

Section: Autoignitive Pre-ignitionmentioning

confidence: 99%

“…7,8 In methanol-fuelled engines, noble metal coatings on spark plug electrodes have been observed to promote surface pre-ignition, 7 as has a calcium-based oil additive. 9 A glow plug was used by Hamilton et al 8 to create surface hot spots at different temperatures to differentiate the propensity to surface pre-ignition and knock intensity between different fuel blends. With ethanol and E85 there was a general tendency for pre-ignition to increase with increases in compression ratio up to 15.…”

Section: Introductionmentioning

confidence: 99%

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Pre-ignition and ‘super-knock’ in turbo-charged spark-ignition engines

Kalghatgi

Bradley

2012

International Journal of Engine Research

251

135

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Earlier studies of pre-ignitions at hot surfaces are first reviewed. The concept of a critical radius of a hot pocket of gas, closely related to the laminar flame thickness, that is necessary to initiate a propagating flame, has been used successfully to predict relative tendencies of different fuel-air mixtures to pre-ignite. As the mixture is compressed, the thickness of potential laminar flames decreases, and when this becomes of the order of the thermal sheath thickness at the hottest surface, pre-ignition can occur there, creating a propagating flame. Measured engine pre-ignition ratings are shown to correlate well with laminar flame thicknesses. Predictions are made concerning the effects of changes in intake temperature and pressure on the pre-ignition of different fuels.A growing current concern is occasional gas-phase, autoignitive, pre-ignitions that can occur in turbo-charged engines, giving rise to very severe autoignition and knock. It is concluded from the evidence of engine pressure records and autoignition delay times of the mixtures that such pre-ignitions have not arisen from autoignition of the fuel, but of a mixture with a smaller autognition delay time than stoichiometric n-heptane-air. One possibility is that autoignition occurs at hot spots containing some lubricating oil. It is shown that such pre-ignitions, particularly with catalytic enhancement, could initiate a propagating flame, rather than autoignitive propagation.In the later, much more severe autoignition arising after pre-ignition, autoignitive propagation velocities at a hot spot are estimated from computed values of the ignition delay times and assumed reactivity gradients in the fuel-air mixture at the hot spot. The severity of the associated pressure pulse is dependent upon the ratios j, of the acoustic speed to the localised autoignitive velocity, and e, of the residence time of the acoustic wave in the hot spot to the short excitation time in which most of the chemical energy is released. The regime in which a localised detonation can be generated in the hot spot is defined by a peninsula on a plot of j against e. A locus is plotted on this figure corresponding to the growing measured intensities of the engine knock as the pressure increases. This is based on computed autoignition delays and excitation times, for an appropriate surrogate fuel. These changes are characterised by j tending to unity and e tending to ever-higher values, with increasingly intense, localised, developing detonations.

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Section: Autoignitive Pre-ignitionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pre-ignition and ‘super-knock’ in turbo-charged spark-ignition engines

Kalghatgi

Bradley

2012

International Journal of Engine Research

251

135

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Ion current measurement in a homogeneous charge compression ignition engine

Tanaka

Narahara

Tabata

et al. 2005

International Journal of Engine Research

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An ion current probe using a spark plug was applied to gasoline-fuelled homogeneous charge compression ignition (HCCI) combustion with hot residual gas in order to verify the possibility of using it as a combustion sensor. The ion current signal for single-cycle HCCI combustion had a simple profile and effectively one maximum value. There is a possibility that a similar ion current signal corresponding to the completed reaction can be obtained, depending on the location of the probe during HCCI combustion. The ionization reaction for HCCI combustion is affected by the chemical ionization reaction with heat release, and there is a possibility that the ion current can be used to detect heat release corresponding to the chemical ionization reaction. A strong correlation between the timing of the integrated ion current and the timing of the mass fraction burned is observed. The timing of the mass fraction burned is assumed from the timing of the integrated ion current, and the mass fraction burned (up to 70 per cent) can be determined, even if the engine driving condition changes within the scope of the test. There is a correlation between the timing of the maximum ion-current and the maximum rate of heat release, and there is a possibility that the maximum value of the rate of heat release can be inferred by detecting the timing of the maximum ion current. There is a correlation between the timing of the maximum ion current and the timing of the maximum pressure at each cycle. Therefore, it may be possible to monitor the variation of the HCCI combustion phasing.

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Methanol as a Fuel for Spark Ignition Engines: A Review and Analysis

Kowalewicz

1993

Proceedings of the Institution of Mechanical Engineers, Part D:

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A review and analysis of recent literature data on the use of methanol as an alternative fuel for internal combustion engines have been performed. The properties of methanol have been analysed from the point of view of its application to spark ignition (SI) and compression ignition (CI) engines. From this analysis it may be concluded that fewer modifications to the engine are expected when methanol is used in SI engines than in CI engines. Neat methanol is the most suitable, because all the positive properties of methanol as a fuel can be utilized. In the case of SI engines, only minor modifications of the fuel system and/or addition of ignition improver to the fuel are required. Use of methanol-gasoline blends of up to 15 per cent methanol (by volume) and diesel oil-methanol blends of up to 20 per cent methanol require only minor engine modifications. However, miscibility of methanol and conventional fuels is poor; in order to avoid fuel separation, mixtures of these fuels require fuel additives. Methanol engines burn cleaner and more efficiently, but have higher emissions of aldehydes, which increase with increasing mileage of the vehicle. In the presence of an oxidation catalyst unburned methanol can be converted to formaldehyde and simultaneously nitrous oxide to nitrogen dioxide. The advantage of engine fuelling with reformed methanol (CO + H2) is shown. The reasons for better efficiency, performance and less emissions (except of aldehydes) of methanol-fuelled SI engines in comparison with gasoline- and diesel oil-fuelled engines respectively have been analysed. Technical aspects of using methanol as an automotive fuel that have not yet been satisfactorily solved are pointed out. The feasibility of the widespread use of methanol as a transportation fuel for SI engines is discussed from technical, economic and ecological points of view. The need for further research and development work on problems related to methanol as a fuel for SI engines is also discussed.

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Abnormal Combustion in a Methanol Fueled Engine

Cited by 5 publications

References 6 publications

Pre-ignition and ‘super-knock’ in turbo-charged spark-ignition engines

Pre-ignition and ‘super-knock’ in turbo-charged spark-ignition engines

Ion current measurement in a homogeneous charge compression ignition engine

Methanol as a Fuel for Spark Ignition Engines: A Review and Analysis

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