Post by thread:[OT] Why Ethanol?

www.popularmechanics.com/science/earth/4237539.html?page=2 Very well summarized op-ed, from a very conservative magazine, that explains why politicians are so hot to require Ethanol fuel production when the current system actually requires as much or more fossil fuels to produce a mile of travel from Ethanol than from just traveling that mile by burning gasoline. Short answer: Corporate welfare. The big winners are ADM (fertilizer), Monsanto (GM Roundup Ready corn), Ford (E85 trucks), and BP (another major contributor to the Bush campaign) among many others. And how are they getting away with it? You're letting them. There is no doubt that better systems could be developed which will increase the yield or provide other source crops, but as far as I can tell, that research is not being funded; the mandate for more Ethanol is simply that: A mandate. Hopefully, the parties involved will fund that research, but in the mean time, the extra goes from my bottom line (in the form of higher gas and food prices) onto theirs. -- James

>> OTOH, Russell was here recently, and since anyone can >> register >> to vote in Califrisco I suppose he has only himself to >> blame... Jinx, >> well, he's probably got it coming... > Tch tch, you take the afternoon off to re-model the frog's > house > and look what you miss James lives in the eternal now, as all good engineers do. "Now" is/was/shall be 2003 for the purposes of the above. I have been/am in Taiwan and China since and willbe/am in Hong Kong from tomorrow and China the same again for a weekish from this Sunday on. Not that I imply infer suggest or whatever by any of the above that the aforementioned special administrative district is not also expl, and impl icitly an intergral part of China. Nor, while we were/are/shall be on the subject, or not, an unmentioned largish island off the coast, which shall be unquestionably, as opposed to questionably as is the case at present, in some minds only, again part of said nation again soon after the events of Europe 1988ish repeat themselves in that area and/or maybe before then but less likely so. Need more sleep :-). Russell > Can't see the Famous Five ... "Five go mad on mescaline" was interesting. Who would have thought that lettuce could be so potent. Timmy.

Hi James, thanks for forwarding that James. My take on this: 1. The type of ethanol pushed by the US administration is the type that is mixed with gasoline. This both prevents the use of high compression engines (15:1 and above) possible with watery (!) alcohol and the reuse or reblending of the fuel for other purposes. It may also support the other industries you have indicated. The type of ethanol pushed by others is the kind that is not mixed with any petroleum products. The lie about 'difficult cold starting' can be proven wrong by anyone who has flick-started a model aircraft engine (that runs on methanol) in any cold January. And the traditional additive to ease cold starts in gas and diesel engines is ether, another more or less natural non-oil derived product. 2. The main crop used to produce Ethanol is not corn, it is sugar cane and beet, followed by potatoes. The US uses a lot of corn for that because they already produce a lot of corn and have the technology in place. Also most large scale Ethanol schemes concentrate on algae grown in the sea. (you probably already know this, but here it is again: http://en.wikipedia.org/wiki/Ethanol_fuel_in_Brazil) 3. The nations whose climates favor them for the production of crops suitable for Ethanol manufacture do not have the resources to buy into American high tech agricultural products. 4. The bullshit about the amount of gasoline consumed to create a unit of Ethanol applies entirely to the forced type of growth and transportation seen in the US. Elsewhere local resources are used massively for this and the numbers look different. For example most sugar cane and beet based sugar and Ethanol factories use the canes and other vegetal remains as fuel to power part of the factory. Of course they are too far away from the US to be usable as such. 5. Genetically engineered crops are seriously frowned upon everywhere outside the US. In Canada there were several major scandals involving GE crops invading neighboring fields and ending up displacing (!!) other types of crops (soy), including at least one farmer who tried to reuse the 'new' crops that landed on his soil and was sued and lost to Monsanto. Knowledge about this has spread and will likely impact any further GE crop use VERY seriously. While Canada, which owns fantastic natural resources, somehow repeatedly ends up playing flexible (and deep bowing) nice little brother to the US, can probably afford to display such stupidity as shown in the GE soy crops case from time to time, other countries cannot. 6. With few countries as exceptions, E85 and other gasoline 'blended' alcohol fuel is not mandatory and the authorities are not very eager to introduce it. Also should the fuel cell business take off, ethanol and methanol can be used directly in some of them, while E85 cannot. The 'blending' business is a license to steal for any country. At least in Brazil, where Exx is the fuel of choice, the price is changed to reflect the energy content of the fuel as it is blended in accordance with the seasonal yield in Ethanol and grain prices. That is about the only place on this planet where the price accounts dynamically in some way for the varying energy content in some way at the gas pump, as far as I know. For these reasons and other, I consider E85 and other similar blends to be a modern analog of poor quality moonshine of the type sold to American Indians once upon a time. The 'real' thing is double distilled Ethanol with 5-30% water in it (and the water only makes it work better in high compression engines). And no, it won't easily run in a stock engine. But if you have any doubt about what it can do, try to remember your model aircraft, boat or car, or Indy races. Because all those engines run (or ran - Indy cars now again use gas) on straight methanol. thanks for writing, Peter --------------------------------- Looking for last minute shopping deals? Find them fast with Yahoo! Search.

> While Canada, which owns fantastic natural resources, > somehow repeatedly ends up playing flexible (and deep > bowing) nice little brother to the US, can probably afford > to display such stupidity as shown in the GE soy crops > case from time to time, other countries cannot. /> NZ can't afford it, but we do it anyway. For reasons far beyond rational understanding (but no doubt tied up with politics and our PM's long term international political aspirations (head of the UN) our country is one of a small cartel of international "hard men" who side with the US and Canada and muddy the genetic engineering waters by vetoing actions that a very very large majority of others would otherwise take. Most NZers (by a large majority) are blissfully unaware that NZ is seen as a pariah on the international ge scene. If we ignore (which one should never do) metaphysical aspects then GE is *the* biggest threat bar none to the continuation of the human race. The only threats of similar magnitude (but not magnitude*occurence_probability product) are a supra dinosaur killer size impact or a gamma ray burster in a closish star system. Both are statistically far less likely to wipe us all out than random small teams of variably qualified people playing with machinery that we so far understand a few percent of the workings of, at best. (Anyone wishing to take exception to that assessment should find out what Craig Venter thinks.)(If you don't know who he is and / or care what he thinks then your exception taking would be of questionable value :-) ). Russell

Hi Peter, Don't forget that for model engines you need a plug that you have to heat up with electricity before flicking the engine. After then it consumes enough heat energy to keep the motor running, however, during cold winter days it still needs to be heated by electricity during the entire running. You can also cheat with added nitro, which generates more heat (and power) or with added oil which reduce heat (and power) but I do not want to set up different mixtures for my car for different weather conditions :-) Also methanol is highly poisonous, even inhaling or touching it is likely to badly affecting your health. It produces formic acid in your body and kills nerve cells making you blind or even killing you. I would not work on petrol station if the fuel contains this material - I choose kill brain cells by alcohol instead <grin> Tamas On Jan 4, 2008 10:07 AM, Peter P. <EraseMEplpeter2006spam_OUTTakeThisOuTyahoo.com> wrote: {Quote hidden}> Hi James, > > thanks for forwarding that James. > > My take on this: > > 1. The type of ethanol pushed by the US administration is the type that is > mixed with gasoline. This both prevents the use of high compression engines > (15:1 and above) possible with watery (!) alcohol and the reuse or > reblending of the fuel for other purposes. It may also support the other > industries you have indicated. The type of ethanol pushed by others is the > kind that is not mixed with any petroleum products. The lie about 'difficult > cold starting' can be proven wrong by anyone who has flick-started a model > aircraft engine (that runs on methanol) in any cold January. And the > traditional additive to ease cold starts in gas and diesel engines is ether, > another more or less natural non-oil derived product. > > 2. The main crop used to produce Ethanol is not corn, it is sugar cane and > beet, followed by potatoes. The US uses a lot of corn for that because they > already produce a lot of corn and have the technology in place. Also most > large scale Ethanol schemes concentrate on algae grown in the sea. (you > probably already know this, but here it is again: > http://en.wikipedia.org/wiki/Ethanol_fuel_in_Brazil) > > 3. The nations whose climates favor them for the production of crops > suitable for Ethanol manufacture do not have the resources to buy into > American high tech agricultural products. > > 4. The bullshit about the amount of gasoline consumed to create a unit of > Ethanol applies entirely to the forced type of growth and transportation > seen in the US. Elsewhere local resources are used massively for this and > the numbers look different. For example most sugar cane and beet based sugar > and Ethanol factories use the canes and other vegetal remains as fuel to > power part of the factory. Of course they are too far away from the US to be > usable as such. > > 5. Genetically engineered crops are seriously frowned upon everywhere > outside the US. In Canada there were several major scandals involving GE > crops invading neighboring fields and ending up displacing (!!) other types > of crops (soy), including at least one farmer who tried to reuse the 'new' > crops that landed on his soil and was sued and lost to Monsanto. Knowledge > about this has spread and will likely impact any further GE crop use VERY > seriously. While Canada, which owns fantastic natural resources, somehow > repeatedly ends up playing flexible (and deep bowing) nice little brother to > the US, can probably afford to display such stupidity as shown in the GE soy > crops case from time to time, other countries cannot. > > 6. With few countries as exceptions, E85 and other gasoline 'blended' > alcohol fuel is not mandatory and the authorities are not very eager to > introduce it. Also should the fuel cell business take off, ethanol and > methanol can be used directly in some of them, while E85 cannot. The > 'blending' business is a license to steal for any country. At least in > Brazil, where Exx is the fuel of choice, the price is changed to reflect the > energy content of the fuel as it is blended in accordance with the seasonal > yield in Ethanol and grain prices. That is about the only place on this > planet where the price accounts dynamically in some way for the varying > energy content in some way at the gas pump, as far as I know. > > For these reasons and other, I consider E85 and other similar blends to be > a modern analog of poor quality moonshine of the type sold to American > Indians once upon a time. The 'real' thing is double distilled Ethanol with > 5-30% water in it (and the water only makes it work better in high > compression engines). And no, it won't easily run in a stock engine. But if > you have any doubt about what it can do, try to remember your model > aircraft, boat or car, or Indy races. Because all those engines run (or ran > - Indy cars now again use gas) on straight methanol. > > thanks for writing, > Peter > > > > --------------------------------- > Looking for last minute shopping deals? Find them fast with Yahoo! > Search. > -

James, On Thu, 3 Jan 2008 13:47:04 -0800, James Newton wrote: {Quote hidden}> www.popularmechanics.com/science/earth/4237539.html?page=2 > > Very well summarized op-ed, from a very conservative magazine, that explains > why politicians are so hot to require Ethanol fuel production when the > current system actually requires as much or more fossil fuels to produce a > mile of travel from Ethanol than from just traveling that mile by burning > gasoline. > > Short answer: Corporate welfare. The big winners are ADM (fertilizer), > Monsanto (GM Roundup Ready corn), Ford (E85 trucks), and BP (another major > contributor to the Bush campaign) among many others. > > And how are they getting away with it? You're letting them. > > There is no doubt that better systems could be developed which will increase > the yield or provide other source crops, but as far as I can tell, that > research is not being funded; the mandate for more Ethanol is simply that: A > mandate. Hopefully, the parties involved will fund that research, but in the > mean time, the extra goes from my bottom line (in the form of higher gas and > food prices) onto theirs. These days there's usually an easy way to see why politicians are doing what they do: "Follow the money"! :-) Interestingly, Ethanol is completely unheard-of on this side of the pond. Greenness is being encouraged in areas such as saving electricity (CFL lightbulbs, home insulation, energy-efficient appliances) and by the ever-rising prices of fuel (Petrol reached 99.9p/litre at my local supermarkets while I was in the 'States, which is more than twice the price you're paying, despite the rises you've seen!), and one of the largest energy suppliers, nPower, just announced a 13% rise in the price of gas, and 17% in the price of electricity, "due to the rising price of oil". Incidentally, we have virtually no coal-fired power stations nowadays - they were converted to gas during the heyday of the North Sea Gas era (sadly almost over now). Cheers, Howard Winter St.Albans, England

Bob, On Fri, 04 Jan 2008 09:35:58 -0800, Bob Barr wrote: {Quote hidden}> On Fri, 04 Jan 2008 16:10:07 +0000 (GMT), "Howard Winter" wrote: > > >James, > > > > snip > > > > (Petrol reached 99.9p/litre at my local supermarkets while I was in the 'States, which is > >more than twice the price you're paying, despite the rises you've seen!), > > > > snip > > > > I understand that the tax levels on fuel are quite high on your side > of the pond but I don't know the rate. Oh yes! > How much of that 99.9p/litre price is the tax? I don't know for sure - there are two elements, "Road fuel duty", which is in pence per litre, and VAT with is 17.5% on everything, including the duty. Liquified Petroleum Gas (LPG, basically propane, I think) is available from some petrol stations, and is almost exactly half of the price of petrol, because there is either less or no road fuel duty on it, so that gives an indication. The government have said that if LPG takes off to the point where there's a significant reduction in the use of petrol (and so the duty raised) they will raise the duty on LPG. GIven the cost of a dual-fuel conversion, and the loss of space due to the LPG tank, the takeup of it isn't great, despite being fairly widely available for a decade or so. > In the US, we have a federal tax that's the same in all of the states > and a separate state tax that varies from one state to another. Well we're just the one State, so it's the same all over the UK (the duty and tax, not the price, which varies by about 10% from the cheapest to dearest places, with Motorway services being the dearest, supermarkets the cheapest). My local ASDA supermarket, the cheapest place I know of, is now charging £1.009 per litre, about US$7.65 per US gallon. Cheers, Howard Winter St.Albans, England

Hi Howard - Believe it or not, not only is there no citizenship test for voter registration in California, it is against the law for Registrars to ask. The registration form has a box which you check to assure posterity that you are a citizen. In the here & now no checking of your statement is required, or in- deed allowed. Russell has only to provide a local address & he's in. regards, Jack On 1/12/08, Howard Winter <KILLspamHDRWKILLspamh2org.demon.co.uk> wrote: {Quote hidden}> John, > > On Thu, 3 Jan 2008 19:37:11 -0800, John Gardner wrote: > > > . > > > And how are they getting away with it? You're letting them. > > > > That's a little rough on Russell & Jinx, don'cha think? > > > > OTOH, Russell was here recently, and since anyone can register to vote > > in Califrisco I suppose he has only himself to > > blame... > > I don't believe this is true - I have friends who've lived in California for > about 15 years (they're Brits with Green Cards), and they can't vote because > they're > foreigners. > > They do have to pay taxes though, which seems to contradict a saying which I > believe was popular over there a couple of hundred years ago! :-) > > Cheers, > > > Howard Winter > St.Albans, England > > > -

John Gardner wrote: > The registration form has a box which you check to assure posterity that > you are a citizen. In the here & now no checking of your statement is > required, or in- deed allowed. Are you sure? The instructions for the voter registration form <http://www.sos.ca.gov/elections/english.pdf> say: "6. ID Number: When you register to vote, you must provide your California driver¢s license or California identification card number, if you have one. If you do not have a driver¢s license or ID card, you must provide the last four digits of your Social Security Number (SSN). If you do not include this information, you will be required to provide identification when you vote." I don't know, but I think that a NZ passport is not a suitable form of identification for voting in CA. > Russell has only to provide a local address & he's in. This latter statement seems to contradict your former statement. He has to provide a local address and lie about his citizen status, doesn't he? This, among other things, can impact future visa requests he may be making. This is not to say it's impossible, but it requires certain personality traits and an approach to life organization that not everybody has. Gerhard

Folks here illegally to begin with (millions) may not be losing much sleep over future visa status. And who said anything about telling the truth? Not wanting to provide a script for evildoers, I'll admit to obfuscating a step, but there is a gaping security hole in the process which is evident to anyone familiar with it, or, more likely, has a mentor/sponsor so inclined... Hint: Motor-Voter best regards, Jack On 1/12/08, Gerhard Fiedler <RemoveMElistsTakeThisOuTconnectionbrazil.com> wrote: {Quote hidden}> John Gardner wrote: > > > The registration form has a box which you check to assure posterity that > > you are a citizen. In the here & now no checking of your statement is > > required, or in- deed allowed. > > Are you sure? The instructions for the voter registration form > <http://www.sos.ca.gov/elections/english.pdf> say: > > "6. ID Number: When you register to vote, you must provide your California > driver's license or California identification card number, if you have one. > If you do not have a driver's license or ID card, you must provide the last > four digits of your Social Security Number (SSN). If you do not include > this information, you will be required to provide identification when you > vote." > > I don't know, but I think that a NZ passport is not a suitable form of > identification for voting in CA. > > > > Russell has only to provide a local address & he's in. > > This latter statement seems to contradict your former statement. He has to > provide a local address and lie about his citizen status, doesn't he? This, > among other things, can impact future visa requests he may be making. > > This is not to say it's impossible, but it requires certain personality > traits and an approach to life organization that not everybody has. > > Gerhard > > -

> -----Original Message----- > From: spamBeGonepiclist-bouncesspamBeGonemit.edu [TakeThisOuTpiclist-bouncesEraseMEspam_OUTmit.edu] On Behalf {Quote hidden}> Of Bob Barr > Sent: 04 January 2008 17:36 > To: Microcontroller discussion list - Public. > Subject: Re: [OT] Why Ethanol? > > I understand that the tax levels on fuel are quite high on your side > of the pond but I don't know the rate. > > How much of that 99.9p/litre price is the tax? > > In the US, we have a federal tax that's the same in all of the states > and a separate state tax that varies from one state to another. As Howard mentions, our tax is made up from a fixed portion which depends on the type of fuel, and Value Added Tax at 17.5%. What really annoys people is that VAT applies to the fixed fuel duty, i.e. they tax the tax. 2007 fuel duty (as of 1 October 2007) in the United Kingdom is: * 50.35 pence per litre for ultra-low sulphur unleaded petrol/diesel * 53.65 pence per litre for conventional unleaded petrol * 56.94 pence per litre for conventional diesel * 30.35 pence per litre for bio-diesel and bio ethanol * 16.49 pence per kg for gas other than natural gas (LPG) * 13.70 pence per kg for natural gas used as road fuel. * 9.69 pence per litre for rebated gas oil (red diesel) * 9.29 pence per litre for rebated fuel oil Assuming ultra-low sulphur unleaded: Cost prior to VAT = 99.9/1.175 = 85.02p Cost prior to fuel duty = 85.02 - 50.35 = 34.67p This gives an equivalent tax rate of (99.9 - 34.67)/34.67 * 100 ~ 188% The post-tax cost of diesel is slightly higher than unleaded now, and the tax rate is quite a bit higher, making them less attractive than they used to be. Also note the comparatively low tax rate on LPG, which is gaining popularity here. Regards Mike ======================================================================= This e-mail is intended for the person it is addressed to only. The information contained in it may be confidential and/or protected by law. If you are not the intended recipient of this message, you must not make any use of this information, or copy or show it to any person. Please contact us immediately to tell us that you have received this e-mail, and return the original to us. Any use, forwarding, printing or copying of this message is strictly prohibited. No part of this message can be considered a request for goods or services. =======================================================================

Mike, Thanks for the details... On Mon, 14 Jan 2008 15:00:15 -0000, Michael Rigby-Jones wrote: {Quote hidden}> 2007 fuel duty (as of 1 October 2007) in the United Kingdom is: > > * 50.35 pence per litre for ultra-low sulphur unleaded petrol/diesel > * 53.65 pence per litre for conventional unleaded petrol > * 56.94 pence per litre for conventional diesel > * 30.35 pence per litre for bio-diesel and bio ethanol > * 16.49 pence per kg for gas other than natural gas (LPG) > * 13.70 pence per kg for natural gas used as road fuel. > * 9.69 pence per litre for rebated gas oil (red diesel) > * 9.29 pence per litre for rebated fuel oil Interesting - the duty on Diesel is more than Petrol - I didn't know that! Notice that the duties on the liquified gasses are per kg, and assuming they are lighter than water (I believe they are, for example petrol has a Specific Gravity of about 0.8, I think) then the duty is possibly about 25% higher than it appears. What's the difference between the last two? I'd have thought that red diesel would be fuel oil rather than gas oil? I always thought there was *no* duty on red diesel - funny how these myths arise! :-) Is there such as thing as "red" petrol, I wonder? It seems a right pain to pay duty for something that isn't going to be used in a vehicle, such as in garden equipment (mowers, strimmers, chainsaws) or in generators. Cheap petrol generators are easy to find, but diesel ones seem to be about three times the price, so to get one to use red diesel would mean a lot of use before it pays for the difference in the running costs. I calculated the cost of using a small (2kW) petrol generator as about UK£1 per kWh, and this was some time ago and as we can see, about 2/3rds of this is duty that isn't due! :-) Cheers, Howard Winter St.Albans, England

Howard, Don't forget that diesel engines have a much higher torque than a petrol one, even at a very low rpm, that's why tracks, ships, trains etc use diesel. It means less fuel consumption and longer lifetime. My old car for example has a 2.5 litre, 6 cyl turbo diesel and the torque is around 320nm. The same with a brand new petrol is somewhere of 200nm. For generators, lawnmowers, cars the rule is the same: if you use it much, then you save fuel (not just the lower price of that) and also the maintenance costs are lower compared to a petrol one, but if you use it rarely it might not worth the initial investment. Tamas On 1/15/08, Howard Winter <RemoveMEHDRWTakeThisOuTh2org.demon.co.uk> wrote: {Quote hidden}> > Mike, > > Thanks for the details... > > On Mon, 14 Jan 2008 15:00:15 -0000, Michael Rigby-Jones wrote: > > > 2007 fuel duty (as of 1 October 2007) in the United Kingdom is: > > > > * 50.35 pence per litre for ultra-low sulphur unleaded petrol/diesel > > * 53.65 pence per litre for conventional unleaded petrol > > * 56.94 pence per litre for conventional diesel > > * 30.35 pence per litre for bio-diesel and bio ethanol > > * 16.49 pence per kg for gas other than natural gas (LPG) > > * 13.70 pence per kg for natural gas used as road fuel. > > * 9.69 pence per litre for rebated gas oil (red diesel) > > * 9.29 pence per litre for rebated fuel oil > > Interesting - the duty on Diesel is more than Petrol - I didn't know that! > > Notice that the duties on the liquified gasses are per kg, and assuming > they are lighter than water (I believe they are, for example petrol has a > Specific Gravity of > about 0.8, I think) then the duty is possibly about 25% higher than it > appears. > > What's the difference between the last two? I'd have thought that red > diesel would be fuel oil rather than gas oil? I always thought there was > *no* duty on red > diesel - funny how these myths arise! :-) Is there such as thing as > "red" petrol, I wonder? It seems a right pain to pay duty for something > that isn't going to be > used in a vehicle, such as in garden equipment (mowers, strimmers, > chainsaws) or in generators. Cheap petrol generators are easy to find, but > diesel ones seem to > be about three times the price, so to get one to use red diesel would mean > a lot of use before it pays for the difference in the running costs. I > calculated the cost > of using a small (2kW) petrol generator as about UK£1 per kWh, and this > was some time ago and as we can see, about 2/3rds of this is duty that isn't > due! :-) > > Cheers, > > > > Howard Winter > St.Albans, England > > > >

> Don't forget that diesel engines have a > much higher torque than a petrol one, > even at a very low rpm ... Be careful of phrasing things in that manner - it canm be misleading. Torque is essentially "Horsepower per RPM" < convert to favourite units>. ie For a given power and torque at a given RPM, if you produce the same power at half the RPM you double the torque, and if you produce it at twice the RPM you halvee the torque. So, saying that "diesel engines make more power than petrol engines" (ignoring the fact that it is an ill defined statement) is the same as saying that diesel engines make their power at lower speeds than (comparable) petrol engines. This may (or may not) be true, but it gives a better indication about what is being claimed than saying thatv they "have more torque". Useful rule of thumb. Torque x RPM = power Torque in kg.m Power in Watts. About 5% wrong. Based on Power (Watt) = 2 x Pi x Torque (kg x g x m) x RPM/60 x The 2Pi.g and the 60 ALMOST cancel. Russell > My old car for example has a 2.5 litre, 6 cyl turbo diesel and the torque is around 320nm. The same with a brand new petrol is somewhere of 200nm. /> *IF* they produce the same power then this means that the petrol engine produces it at 320/200 = 60% higher speed than the diesl.

Apptech wrote: > Useful rule of thumb. For some values of "useful" :) > Torque x RPM = power > > Torque in kg.m > Power in Watts. FWIW, I don't know any measurement system in current use where torque is measured in kg m. There has been one in use where torque was measured in kp m (which would have a numeric value close to what kg m could mean if it were torque :), but I'm not sure there are many on this list who have heard of it. In any case, there's probably no place where you find torque specified or graphed in kg m. Currently, at least in the realm where one talks about kg and m, torque is measured in N m. And in that system, the rule is not really useful. > Based on > > Power (Watt) = 2 x Pi x Torque (kg x g x m) x RPM/60 x > > The 2Pi.g and the 60 ALMOST cancel. While this is correct, the thing is that after you cancel out the g (which is part of the torque), the "torque" that remains is no torque anymore. Not in units, not in numbers, not in meaning. So given that one has to do some scaling anyway, it's possibly more useful to give the (approximate) scaling factor: P [W] = speed [rpm] * torque [Nm] / 10 or P [hp] = speed [rpm] * torque [Nm] / 7000 P [hp] = speed [rpm] * torque [lbf ft] / 5200 Gerhard

Yes that's true, however, diesel and petrol works different. On diesel the amount of air is always the same while the amount of fuel is changed (quality controlled), while on a petrol the quality of the mixture is the same while the amount of it changed (quantity controlled). Maybe it has been improved a bit for modern engines using injectors and turbo chargers for both type, but the principal should be still the same. It means that for a diesel the higher the rotation speed the higher power coming out from, while a petrol has nice a curve, where there is a well seen optimum speed when the torque is the highest - till and from that point the outcome power is less and less even though the rotation is higher. With a diesel the torque is not much less at slow rotation and it graduately increasing with the speed till it falls apart. So when we talk about horse power we have to keep in mind that for a petrol they give this number for that optimal rotation speed - you can see that number in the brochure sometimes. However, because of the same engine size of petrol spins much faster than diesel, petrol engines are much "powerful". My engine for example spins around 1500 rpm when driving at 90km/h (55mph), but it has an automatic gear box which is very comfortable but the ratio is far from the optimal. In the opposite, my father's car (which is a Ford Mondeo - and Ford has a reputation of low rpm engines) spins almost the double at that speed with a manual gear. It can easily reach 180 km/h where the engine spins somewhere around 6k rpm - that would kill my diesel engine instantly :-) Tamas On 1/16/08, Gerhard Fiedler <listsEraseME.....connectionbrazil.com> wrote: {Quote hidden}> > Apptech wrote: > > > Useful rule of thumb. > > For some values of "useful" :) > > > Torque x RPM = power > > > > Torque in kg.m > > Power in Watts. > > FWIW, I don't know any measurement system in current use where torque is > measured in kg m. There has been one in use where torque was measured in > kp > m (which would have a numeric value close to what kg m could mean if it > were torque :), but I'm not sure there are many on this list who have > heard > of it. In any case, there's probably no place where you find torque > specified or graphed in kg m. > > Currently, at least in the realm where one talks about kg and m, torque is > measured in N m. And in that system, the rule is not really useful. > > > Based on > > > > Power (Watt) = 2 x Pi x Torque (kg x g x m) x RPM/60 x > > > > The 2Pi.g and the 60 ALMOST cancel. > > While this is correct, the thing is that after you cancel out the g (which > is part of the torque), the "torque" that remains is no torque anymore. > Not > in units, not in numbers, not in meaning. > > So given that one has to do some scaling anyway, it's possibly more useful > to give the (approximate) scaling factor: > > P [W] = speed [rpm] * torque [Nm] / 10 > > or > > P [hp] = speed [rpm] * torque [Nm] / 7000 > P [hp] = speed [rpm] * torque [lbf ft] / 5200 > > Gerhard > > -

> On diesel the amount of air is always the same ,,, In the real world volumetric efficiency of IC engines varies with rpm - And of course with boost, if fitted. > there is a well seen optimum speed when the torque is the highest - till and from that point the outcome power is less... Not so. In normally-aspirated spark-ignition engines torque will peak at the rpm at which volumetric efficiency begins to decline. Power, however, will continue to increase with RPM until Vol Eff decreases past the point where increased RPM do not compensate for torque loss. The same applies to diesels, although it is much less noticeable because most diesels are RPM-limited well below the speed at which VEff starts to fall off. best regards, Jack On 1/16/08, Tamas Rudnai <EraseMEtamas.rudnaigmail.com> wrote: {Quote hidden}> Yes that's true, however, diesel and petrol works different. On diesel the > amount of air is always the same while the amount of fuel is changed > (quality controlled), while on a petrol the quality of the mixture is the > same while the amount of it changed (quantity controlled). Maybe it has been > improved a bit for modern engines using injectors and turbo chargers for > both type, but the principal should be still the same. It means that for a > diesel the higher the rotation speed the higher power coming out from, while > a petrol has nice a curve, where there is a well seen optimum speed when the > torque is the highest - till and from that point the outcome power is less > and less even though the rotation is higher. With a diesel the torque is not > much less at slow rotation and it graduately increasing with the speed till > it falls apart. So when we talk about horse power we have to keep in mind > that for a petrol they give this number for that optimal rotation speed - > you can see that number in the brochure sometimes. > > However, because of the same engine size of petrol spins much faster than > diesel, petrol engines are much "powerful". My engine for example spins > around 1500 rpm when driving at 90km/h (55mph), but it has an automatic gear > box which is very comfortable but the ratio is far from the optimal. In the > opposite, my father's car (which is a Ford Mondeo - and Ford has a > reputation of low rpm engines) spins almost the double at that speed with a > manual gear. It can easily reach 180 km/h where the engine spins somewhere > around 6k rpm - that would kill my diesel engine instantly :-) > > Tamas > > > > On 1/16/08, Gerhard Fiedler <RemoveMElistsEraseMEEraseMEconnectionbrazil.com> wrote: > > > > Apptech wrote: > > > > > Useful rule of thumb. > > > > For some values of "useful" :) > > > > > Torque x RPM = power > > > > > > Torque in kg.m > > > Power in Watts. > > > > FWIW, I don't know any measurement system in current use where torque is > > measured in kg m. There has been one in use where torque was measured in > > kp > > m (which would have a numeric value close to what kg m could mean if it > > were torque :), but I'm not sure there are many on this list who have > > heard > > of it. In any case, there's probably no place where you find torque > > specified or graphed in kg m. > > > > Currently, at least in the realm where one talks about kg and m, torque is > > measured in N m. And in that system, the rule is not really useful. > > > > > Based on > > > > > > Power (Watt) = 2 x Pi x Torque (kg x g x m) x RPM/60 x > > > > > > The 2Pi.g and the 60 ALMOST cancel. > > > > While this is correct, the thing is that after you cancel out the g (which > > is part of the torque), the "torque" that remains is no torque anymore. > > Not > > in units, not in numbers, not in meaning. > > > > So given that one has to do some scaling anyway, it's possibly more useful > > to give the (approximate) scaling factor: > > > > P [W] = speed [rpm] * torque [Nm] / 10 > > > > or > > > > P [hp] = speed [rpm] * torque [Nm] / 7000 > > P [hp] = speed [rpm] * torque [lbf ft] / 5200 > > > > Gerhard > > > > --