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Dec 31, 2012 18:28:39 GMT
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I'm having a bit of trouble find a good source of info on air fuel ratios of engines, basicaly i have to answer this question "A gasoline engine has a theoretically correct (stoichiometric) air/fuel ratio of 14.7:1. This is a gravimetric ratio – explain what that means with respect to air/fuel ratio." so does anyone know of any good sites/ book?  |
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Dec 31, 2012 19:09:46 GMT
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Don't want to do your work for you, but think Gravimetric -> gravity. As opposed to, say, the strength of an alcoholic drink which is measured in ABV.  Also: Wikipedia does have that information on it. No good if you need to reference something, but a useful source of information. |
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Last Edit: Dec 31, 2012 19:10:09 GMT by jrevillug
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Dec 31, 2012 20:16:47 GMT
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yer i don't want people doing my work lol
i did check wiki but like you say cant reference it.... and it didnt have any good links/references
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kabman
Part of things
Posts: 348 
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Dec 31, 2012 20:37:30 GMT
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'Internal combustion engine fundamentals' by Heywood is a standard text on the subject.
'Gravimetric' ratio just means a ratio of masses. The alternative is 'Volumetric' which is, unsurprisingly, a ratio of volumes.
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Dec 31, 2012 21:11:10 GMT
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Bang on Kabman, as you say 'internal combustion engine fundamentals' - Heywood This is a bible for all engine designers / calibrators and anyone with a detailed interest in engines  Gravimetric means by mass, so 1 part fuel to 14.7 parts air, the ratio by volume would be very very different. Bear in mind that 14.7 is stoich, and is not best for power or economy, it is however very good for cats You better quote me as a source, and tell me what grade you got |
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Dec 31, 2012 23:08:51 GMT
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Bang on Kabman, as you say 'internal combustion engine fundamentals' - Heywood This is a bible for all engine designers / calibrators and anyone with a detailed interest in engines Gravimetric means by mass, so 1 part fuel to 14.7 parts air, the ratio by volume would be very very different. Bear in mind that 14.7 is stoich, and is not best for power or economy, it is however very good for cats You better quote me as a source, and tell me what grade you got the next question is along the lines of why is 14.7 to 1 not best for power or economy... haha ill try and find that book then when i get back to uni on wens! does anyone know of any websites till then? |
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Dec 31, 2012 23:18:44 GMT
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Surely it is in your lecture notes?
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you would have thought so! i cant find it anywhere!!!
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just means ratio by mass of air to mass of fuel under standard conditions, but yep Heywood will explain some more
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Stu from Motorsport Developments (a Cossie tuning company) wrote a load of technical features for Fast Ford mag which are avaiable on his website, two of them are on AFRs. They might be a bit amateur level for uni coursework, but there's plenty of other interesting features he's written on performance motor engineering. www.motorsport-developments.co.uk/stus.html |
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I've got Rovers.
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Stu from Motorsport Developments (a Cossie tuning company) wrote a load of technical features for Fast Ford mag which are avaiable on his website, two of them are on AFRs. They might be a bit amateur level for uni coursework, but there's plenty of other interesting features he's written on performance motor engineering. www.motorsport-developments.co.uk/stus.htmlthnaks for that link mate, loads of info there |
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Doing air/fuel for mass ratios is important as the volume of a gas changes with temperature. A lean burn could be 16:1 but at what the ratio often drops to 12.5:1 or there abouts. A lean burn get hot so this is only used for part trottle/low revs or the heat build up would do damage to the exhaust valves. A rich burn is used at higher revs and what throttle condition as the heat build is lower and power is improved as combustion time is reduced so more fuel is need for a volume of air to get the required energy out.
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Find the Heywood, as mentioned, along with: Automotive Fuel and Fuel Systems, Volume 1 by T.K. Garrett, Introduction to Internal Combustion Engines by Richard Stone Combustion Systems of High-Speed I.C. Engines by A. Kowalewicz Those four books, especially the last one, made up a fairly substantial proportion of my dissertation. Which was basically about mixture formation |
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Last Edit: Jan 6, 2013 2:22:07 GMT by Rich606
1989 Peugeot 205. You know, the one that was parked in a ditch on the campsite at RRG'17... the glass is always full. but the ratio of air to water may vary. |
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Find the Heywood, as mentioned, along with: Automotive Fuel and Fuel Systems, Volume 1 by T.K. Garrett, Introduction to Internal Combustion Engines by Richard Stone Combustion Systems of High-Speed I.C. Engines by A. Kowalewicz Those four books, especially the last one, made up a fairly substantial proportion of my dissertation. Which was basically about mixture formation sweet thanks, looks like a good list |
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