Some Concepts of Knock and Antiknock Action

Sturgis, B. M.

doi:10.4271/550249

Cited by 22 publications

(25 citation statements)

References 6 publications

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“…Addition of DIB of 24% (v/v) in HEP results in the increase of the cool flame duration (in terms of CR) by 3.9, compared to no addition of DIB. 17 The same inhibitory effect of DIB addition in HEP has been observed in the HCCI engine by Shibata and Urushihara. 16 The gradual additions of DIB (49, 54, 58, to 62% (v/v)) in HEP improve their octane number (ON) by 5 (RON 75, 80, 85, and 90) and results in a gradual delay of CA 50 from TDC (RON 75) to 5°A TDC (RON 90).…”

Section: Resultssupporting

confidence: 59%

“…In a previous study on knock chemistry of HEP and DIB, Sturgis reported that HEP decomposition favored formation of aldehydes and ketones, and no noticeable intermediate products from partial oxidation of DIB can be observed until just prior to autoignition. 17 This observation also supports less active participation of DIB during the low temperature reaction of HEP and DIB blends, except the formation of 4,4-dimethyl-2-pentanone.…”

Section: Condensed Intermediate Hydrocarbon Speciesmentioning

confidence: 51%

“…Previous motored engine studies of ignition chemistry in the low temperature reaction regime have demonstrated that taking an exhaust sample at selected CR very close to CCR can provide a wide range of large oxygenated intermediate species, including conjugate olefins well-known as major products during low temperature oxidation. 17,23 As shown in Table 2 and mentioned earlier, the mixtures with 15 and 20% (v/v) addition of DIB to ISO were unable to reach the critical compression ratio, indicating that the full ignition was not able to be achieved under these conditions, since the maximum capacity of the compression ratio on this CFR engine is 15.7. For this reason, only nine blends were explored including the five different sets of HEP blends and four different sets of ISO blends.…”

Section: Condensed Intermediate Hydrocarbon Speciesmentioning

confidence: 88%

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Combined Impact of Branching and Unsaturation on the Autoignition of Binary Blends in a Motored Engine

et al. 2014

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The impact of a branched and unsaturated compound (diisobutylene) mixed with simple hydrocarbons such as nheptane and isooctane in binary blends on the autoignition behavior were investigated in a modified cooperative fuel research (CFR) engine at an equivlanece ratio of 0.5 and intake temperature of 120°C. From this test condition, a homogeneous charge of fuel and intake air can be achieved. The test fuels were prepared by addition of 5−20 vol % diisobutylene into n-heptane and isooctane. The engine compression ratio (CR) was gradually increased from the lowest point to the point where significant high temperature heat release (HTHR) was observed, and this point is also referred to as the critical compression ratio (CCR). Heat release analysis showed that each n-heptane blend had a noticeable low temperature heat release (LTHR), which was not observed in the isooctane blends. The gradual addition of diisobutylene into each primary reference fuel contributed to retarded high temperature heat release in these binary blends, increasing the in-cylinder temperature and decreasing formation of CO. The 15 and 20 vol % blends of diisobutylene in isooctane were not able to reach high temperature heat release in the CFR engine system under these test conditions. The fundamental ignition behavior such as CCR and calculated % LTHR show the impact of the presence of the C−C double bond on ignition reactivity. Species concentration profiles obtained in condensed products from the engine exhaust were measured via gas chromatrography−mass spectrometry and −flame ionization detector. The major intermediate species for each blend were captured at a compression ratio selected just before the high temperature heat release was observed. Most intermediate species were derived from n-heptane and isooctane, while diisobutylene rarely participated in forming any major species, with the exception of the formation of 4,4-dimethyl-2-pentanone. Addition of diisobutylene exhibited opposite trends with regard to the abundance of intermediate species when blended with n-heptane versus with isooctane, due to the different degree of oxidation reactivity of n-heptane in comparison to isooctane.

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Section: Resultssupporting

confidence: 59%

Section: Condensed Intermediate Hydrocarbon Speciesmentioning

confidence: 51%

Section: Condensed Intermediate Hydrocarbon Speciesmentioning

confidence: 88%

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Combined Impact of Branching and Unsaturation on the Autoignition of Binary Blends in a Motored Engine

et al. 2014

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“…However, some preliminary experiments that we have performed and also data in the literature have shown that internal combustion engines in general (Sturgis, 1955;~leicklein, 1976), and diesel engines in particular, are a significant source of primary oxidants. For example, approximately one-third of sulfur from diesel fuel is oxidized to sulfate when the diesel engine exhaust is sampled in a water bubbler.…”

mentioning

confidence: 90%

“…We also demonstrate the role of these primary oxidants in the oxidation of SOz in fog droplets and the formation of suspended sulfates under laboratory conditions. The origin of the primary oxidants is the precombustion reactions between fuel molecules and oxygen, with reaction intermediates (Sturgis, 1955;Heicklein, 1976). During perfect combustion, these species will be oxidized to co 2 and H 2 o.…”

Section: Introductionmentioning

confidence: 99%