Octane-on-Demand as an Enabler for Highly Efficient Spark Ignition Engines and Greenhouse Gas Emissions Improvement

Chang, Junseok; Viollet, Yoann; Alzubail, Abdullah; Abdul-Manan, Amir F.N.; Arfaj, Abdullah Al

doi:10.4271/2015-01-1264

Cited by 40 publications

(31 citation statements)

References 19 publications

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“…Several literature suggest that these refinery streams could be suitable octane boosters to produce SI engine fuels [36]. Such low octane fuels have earlier proved to be ideal for advanced engine concepts like octane-on-demand, which uses a low octane fuel as its base fuel and an octane booster, as and when required [37,38]. Heat release analyses of the experiments were done considering first law analysis and heat losses from heat transfer to the wall, crevices and blow-by losses.…”

Section: Experimental Heat Release Analysismentioning

confidence: 99%

Simulating HCCI Blending Octane Number of Primary Reference Fuel with Ethanol

Singh¹,

Waqas²,

Johansson³

et al. 2017

SAE Technical Paper Series

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The blending of ethanol with primary reference fuel (PRF) mixtures comprising n-heptane and iso-octane is known to exhibit a non-linear octane response; however, the underlying chemistry and intermolecular interactions are poorly understood. Well-designed experiments and numerical simulations are required to understand these blending effects and the chemical kinetic phenomenon responsible for them. To this end, HCCI engine experiments were previously performed at four different conditions of intake temperature and engine speed for various PRF/ethanol mixtures. Transfer functions were developed in the HCCI engine to relate PRF mixture composition to autoignition tendency at various compression ratios. The HCCI blending octane number (BON) was determined for mixtures of 2-20 vol % ethanol with PRF70. In the present work, the experimental conditions were considered to perform zerodimensional HCCI engine simulations with detailed chemical kinetics for ethanol/PRF blends. The simulations used the actual engine geometry and estimated intake valve closure conditions to replicate the experimentally measured start of combustion (SOC) for various PRF mixtures. The simulated HCCI heat release profiles were shown to reproduce the experimentally observed trends, specifically on the effectiveness of ethanol as a low temperature chemistry inhibitor at various concentrations. Detailed analysis of simulated heat release profiles and the evolution of important radical intermediates (e.g., OH and HO 2 ) were used to show the effect of ethanol blending on controlling reactivity. A strong coupling between the low temperature oxidation reactions of ethanol and those of n-heptane and iso-octane is shown to be responsible for the observed blending effects of ethanol/PRF mixtures.

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Section: Experimental Heat Release Analysismentioning

confidence: 99%

Simulating HCCI Blending Octane Number of Primary Reference Fuel with Ethanol

Singh¹,

Waqas²,

Johansson³

et al. 2017

SAE Technical Paper Series

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“…Naphtha was a "less processed" gasoline with RON in the range of 60-85. 13 Its distillation range was similar to gasoline from ~20°C to ~200°C. The use of naphtha also had the potential to reduce greenhouse gas because of less processing requirement and less energy used in refinery.…”

mentioning

confidence: 87%

“…Extremely low NO x and soot emissions were gained as a result of the “enough premixing” and low temperature combustion. Naphtha was a “less processed” gasoline with RON in the range of 60‐85 . Its distillation range was similar to gasoline from ~20°C to ~200°C.…”

Section: Introductionmentioning

confidence: 99%

Autoignition of light naphtha and its surrogates in a rapid compression machine

Wang

2019

Energy Science & Engineering

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Gasoline Compression Ignition (GCI) is a promising combustion mode to improve engine efficiency and reduce emissions. Naphtha has higher ignitability than gasoline and could be a better fuel for GCI. Understanding the autoignition behavior of naphtha is essential for the development of GCI engines. In this study, the ignition delay of light naphtha and its three surrogates, including PRF59 (59% iso‐octane and 41% n‐heptane in volume) and two three‐component surrogates composed of methyl‐cyclohexane, n‐heptane, and iso‐octane with blending ratios of 33.8%/43.2%/23% (MRF1) and 31.4%/33.3%/35.3% (MRF2) in volume were studied using a rapid compression machine. PRF59 was selected by matching the RON of light naphtha. MRF1 was composited by matching the RON and MON of light naphtha, while MRF2 was composed by matching RON and H/C. The experiments were conducted at equivalence ratio Φ = 0.5 and 1, P = 10, 20, and 30 bar, and temperature range of 665‐965 K. It was found that MRF2 best matched the first‐stage and total ignition delays of light naphtha, while PRF59 exhibited shorter first‐stage ignition delay. Although the ignition delay times of MRF1 and MRF2 were very close to each other, uncertainty analysis showed that matching RON and H/C ratio was a better method in determining the blending ratio. In addition, the MRF experiments were compared with predictions using the detailed mechanism. The mechanism showed good performance in reproducing the total ignition delay at high‐pressure conditions, but it underpredicted the ignition delay at low pressure. Also, the mechanism predicted less pronounced NTC behavior.

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“…In some existing SI vehicles equipped with closedloop knock detection algorithms, the use of a higher octane fuel also allows for the engines to advance their spark timing to enhance performance and efficiency. However, in typical real world driving, the octane appetite of engines varies with the operating conditions and, under most conditions, the octane needs of the engine can be satisfied by modest octane levels (Partridge et al, 2014;Chang et al, 2015). It is only under more severe loads that higher octane fuels are needed to ensure optimal performance and efficiency (Liu et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Exploring Alternative Octane Specification Methods for Improved Gasoline Knock Resistance in Spark-Ignition Engines

2018

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Different octane specification methods were evaluated under rising ethanol blending volumes by adopting a refinery economics model to represent a region in the U.S. It was demonstrated that the traditional octane specification methods, such as the Anti-knock Index (AKI) used in the U.S., or the Research Octane Number (RON) and Motor Octane Number (MON) used in the EU, can lead to counterintuitive drop in octane sensitivity with increased availability of ethanol. This is undesirable for modern gasoline engines that require fuels with high RON and low MON, but it is a consequence of how a refinery reformulates the gasoline blendstock, resulting in more naphtha being used in the final composition. The use of a new specification method based on octane index (OI), with engine constant K = −1, internalizes the diminishing role that MON plays in modern engines, thus ensures that the desirable anti-knock quality is being met either through higher RON and/or higher sensitivity. Initial assessment suggests a potential engine efficiency benefit (∼ 1.5%) to be gained simply by switching from an AKI-based specification method to an equivalent OI-based method.

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Octane-on-Demand as an Enabler for Highly Efficient Spark Ignition Engines and Greenhouse Gas Emissions Improvement

Cited by 40 publications

References 19 publications

Simulating HCCI Blending Octane Number of Primary Reference Fuel with Ethanol

Simulating HCCI Blending Octane Number of Primary Reference Fuel with Ethanol

Autoignition of light naphtha and its surrogates in a rapid compression machine

Exploring Alternative Octane Specification Methods for Improved Gasoline Knock Resistance in Spark-Ignition Engines

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