Experimental Studies on Controlled Auto-ignition (CAI) Combustion of Gasoline in a 4-Stroke Engine

Oakley, Aaron J.; Zhao, Hua; Ladommatos, Nicos; Ma, Tom

doi:10.4271/2001-01-1030

Cited by 127 publications

(65 citation statements)

References 9 publications

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“…Oakley et al [9,10] extended the investigation by performing detailed analysis of the heat release characteristics of the CAI combustion process in a 4-stroke gasoline engine. They found that the conventional Octane number is inadequate to describe the autoignition behaviour of fuels in a CAI engine.…”

Section: Introductionmentioning

confidence: 99%

Performance and Analysis of a 4-Stroke Multi-Cylinder Gasoline Engine with CAI Combustion

Zhao

Jian

et al. 2002

SAE Technical Paper Series

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166

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Controlled Auto-Ignition (CAI) combustion was realised in a production type 4-stroke 4-cylinder gasoline engine without intake charge heating or increasing compression ratio. The CAI engine operation was achieved using substantially standard components modified only in camshafts to restrict the gas exchange processThe engine could be operated with CAI combustion within a range of load (0.5 to 4 bar BMEP) and speed (1000 to 3500 rpm). Significant reductions in both specific fuel consumption and CO emissions were found. The reduction in NOx emission was more than 93% across the whole CAI range. Though unburned hydrocarbons were higher under the CAI engine operation.In order to evaluate the potential of the CAI combustion technology, the European NEDC driving cycle vehicle simulation was carried out for two identical vehicles powered by a SI engine and a CAI/SI hybrid engine, respectively. The simulation results showed only moderate improvement in fuel economy and exhaust emissions because of low utilisation of CAI during the drive cycle.In order to take full advantage of the CAI combustion technology, detailed analyses were carried out on the engine's performance, heat release and combustion characteristics, emissions and the effect of gas exchange processes. These analyses showed that the engine's performance and emissions were mainly affected by the trapped residual fractions and residual temperature. In addition, the backflow was found to affect the combustion and emission as well.

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Section: Introductionmentioning

confidence: 99%

Performance and Analysis of a 4-Stroke Multi-Cylinder Gasoline Engine with CAI Combustion

Zhao

Jian

et al. 2002

SAE Technical Paper Series

Self Cite

166

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“…Such combustion has grown in interest in recent years originally arising from works on 2-stroke engines [1][2][3][4][5][6][7][8][9][10] now has crossed to 4-stroke engines [11][12][13][14][15][16][17][18]. The reason for the interest in 4-stroke engines stems from the fact that CAI combustion holds considerable promise as a part-load throttle-less engine control strategy which is capable of yielding superior fuel economy and significantly reduced pollutants [19,20].…”

Section: Introductionmentioning

confidence: 99%

On the Mechanism of Controlled Auto Ignition

Law¹,

Allen²,

Chen³

2002

SAE Technical Paper Series

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“…We defined the lower (misfire) limit as 90% molar conversion of C from fuel to CO 2 , corresponding to incomplete combustion [73,74]. Figure 2 shows sample pressure traces for HCCI simulations of PRF0 (n-heptane) at a compression ratio of 9.5, initial temperature of 330 K, initial pressure of 1 atm, and an engine speed of 1400 rpm, with representative examples of knock, normal combustion, and misfire using the described limits.…”

Section: Fuel Operating Envelopementioning

confidence: 99%

Investigation of the LTC fuel performance index for oxygenated reference fuel blends

Niemeyer

Daly

Cannella

et al. 2015

Fuel

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A new metric for ranking the suitability of fuels in LTC engines was recently introduced, based on the fraction of potential fuel savings achieved in the FTP-75 light-duty vehicle driving cycle. In the current study, this LTC fuel performance index was calculated computationally and analyzed for a number of fuel blends comprised of n-heptane, isooctane, toluene, and ethanol in various combinations and ratios corresponding to octane numbers from 0 to 100. In order to calculate the LTC index for each fuel, computational driving cycle simulations were first performed using a typical light-duty passenger vehicle, providing pairs of engine speed and load points. Separately, for each fuel blend considered, single-zone naturally aspirated HCCI engine simulations with a compression ratio of 9.5 were performed in order to determine the operating envelopes. These results were combined to determine the varying improvement in fuel economy offered by fuels, forming the basis for the LTC fuel index. The resulting fuel performance indices ranged from 36.4 for neat n-heptane (PRF0) to 9.20 for a three-component blend of n-heptane, isooctane, and ethanol (ERF1). For the chosen engine and chosen conditions, in general lower-octane fuels performed better, resulting in higher LTC fuel index values; however, the fuel performance index correlated poorly with octane rating for less-reactive, higher-octane fuels.

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Experimental Studies on Controlled Auto-ignition (CAI) Combustion of Gasoline in a 4-Stroke Engine

Cited by 127 publications

References 9 publications

Performance and Analysis of a 4-Stroke Multi-Cylinder Gasoline Engine with CAI Combustion

Performance and Analysis of a 4-Stroke Multi-Cylinder Gasoline Engine with CAI Combustion

On the Mechanism of Controlled Auto Ignition

Investigation of the LTC fuel performance index for oxygenated reference fuel blends

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