A New Electrical Engine-Indicator

Martin, E. J.; Caris, D. F.

doi:10.4271/280050

Cited by 3 publications

(4 citation statements)

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“…An issue with such systems was separating vibration effects of the instrument from pressure oscillations due to knock. The natural frequencies of the instruments were between 1200 Hz and 1700 Hz [18]-too low to measure typical knock-driven pressure oscillations. An alternative system was a string galvanometer constructed by Professor Augustus Trowbridge [19] of Princeton University, which recorded the rate of change of cylinder pressure on the photographic film.…”

Section: Mixture Strengthmentioning

confidence: 98%

“…The bouncing pin was said to be the most common device in use. In 1928, a new electrical indicator was described by Martin and Caris [18] of GM. This enabled registering of single cycles on photographic film at frequencies of several kilohertz.…”

Section: Mixture Strengthmentioning

confidence: 99%

“…Kalghatgi [355] in 2014 commented that PRF fuels were fundamentally not representative of modern gasolines, and hence, it would make sense to move to an n-heptane/toluene rating scale [355]. 18 Kalghatgi showed that typical modern gasolines could be much better matched in terms of RON and S and, as a consequence, in terms of knock-limited performance on a modern boosted engine, with binary toluene/n-heptane blends. A perfect match of RON and S is possible with a threecomponent surrogate (iso-octane, n-heptane, and toluene).…”

Section: The 2010s: Aggressive Co 2 Targets Electrification and Downs...mentioning

confidence: 99%

“…[362]. © SAE International 18 Ricardo had suggested in 1922 to use another aromatic, benzene, as the knock-resistant hydrocarbon in the rating scale [6], but in the end, isooctane became the knock-resistant reference for RON and MON testing as already discussed. At the time typical octane values were in the range 40-60 and fuel sensitivity was also lower [30].…”

Section: The 2010s: Aggressive Co 2 Targets Electrification and Downs...mentioning

confidence: 99%

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Knock: A Century of Research

Corrigan¹,

Fontanesi²

2021

SAE Int. J. Engines

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Knock is one of the main limitations on increasing spark-ignition (SI) engine efficiency. This has been known for at least 100 years, and it is still the case today. Knock occurs when conditions ahead of the flame front in an SI engine result in one or more autoignition events in the end gas. The autoignition reaction rate is typically much higher than that of the flame-front propagation. This may lead to the creation of pressure waves in the combustion chamber and, hence, an undesirable noise that gives knock its name. The resulting increased mechanical and thermal loading on engine components may eventually lead to engine failure. Reducing the compression ratio lowers end-gas temperatures and pressures, reducing end-gas reactivity and, hence, mitigating knock. However, this has a detrimental effect on engine efficiency.Automotive companies must significantly reduce their fleet carbon dioxide (CO 2 ) values in the coming years to meet targets resulting from the 2015 Paris Agreement. One path towards meeting these is through partial or full electrification of the powertrain. However, the vast majority of automobiles in the near future will still feature a gasoline-fueled SI engine; hence, improvements in combustion engine efficiency remain fundamental.As knock has been a key limitation for so long, there is a huge amount of literature on the subject. A number of reviews on knock have already been published, including in recent years. These generally concentrate on current understanding and status. The present work, in contrast, aims to track the progress of research on knock from the 1920s right through to the present day. It is hoped that this can be a useful reference for new and existing researchers of the subject and give further weight to occasionally neglected historical activity, which can still provide important insights today.

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Section: Mixture Strengthmentioning

confidence: 98%

Section: Mixture Strengthmentioning

confidence: 99%