Coordinating Research Council Quantifying Performance of Knock-Sensor Equipped Vehicles With Varying Octane Level Fuels

McNally, M. J.; Benson, Jack D.; Callison, James C.; Graham, John; Wusz, Tim; Evans, Beth

doi:10.4271/892037

Cited by 7 publications

(1 citation statement)

References 5 publications

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“…As knock had effectively become a closed loop in production vehicles, their octane appetite could be compared by evaluating acceleration times on a range of different fuels. McNally et al [170] observed in a 1989 Coordinating Research Council (CRC) report that over a range of 15 cars, the Normally Aspirated (NA) models did not improve with a RON value higher than 87, while turbocharged models benefited from RON values as high as 100. Sutton et al [171] stated that from 1945 to 1980 compression ratios had increased significantly.…”

Section: The 1980s: Electronic Ignition Control Computerized Analysis...mentioning

confidence: 99%

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: The 1980s: Electronic Ignition Control Computerized Analysis...mentioning

confidence: 99%