From all the rumors, and I stress RUMORS, the Ferrari is supposedly thirsty and the Renault is a fuel miser....
Well I was wondering with all that is regulated in the FIA engine specs (bore centers, camshaft location, alloys, bore stroke maximum ratio, CG, etc.) there isn't that much that could make one engine more thirsty with the same ECU.
Certain mechanical losses such as heat/lubrication losses, oil windage losses, valve train losses (ramp angles), hydraulics, etc. are all bound to be within a couple of percentage points of each other. So I must view claims that the Renault can get by with 20Kg less fuel over a race as wild fantasy.
Can anyone openly speculate in an educated manner about how much variance you could have with all the things that are regulated to virtual similitude? Let us say that Ferrari got everything as wrong as possible and Renault got everything as correct as possible... OK so what? Same ECU, same bore/stroke, same camshaft locations, same alloys, essentially the same lubrication, same fuel, same, same, same... Could there be any more than 2-3% difference between the Ferrari and the Renault given all the similitude? And 3% of 160Kg is 5Kg max. 2% is 3.2Kg. Not signifigant when one considers that it will be 2.5Kg (or 1.6Kg) at half race distance and decreasing with every lap.
I look forward to your educated replies and comments. For the life of me I cannot see as credible all these claims about fuel consumption varying in any consequential way.
Innovation over refinement is the prefered path to performance. -- Get rid of the dopey regs in F1
The method was looking at actual non KERS consumption of the Ferrari and Renault engine. We agreed that there is potential for significant differences. It is also clear that the level of downforce will influence consumption. The cars with better downforce tend to run on higher throttle setting on average and consume more fuel.
Formula One's fundamental ethos is about success coming to those with the most ingenious engineering and best ..............................organization, not to those with the biggest budget. (Dave Richards)
I think KERS has very little (it if has any at all) contribution to fuel consumption. Let's do some math:
KERS was restricted to 400kJ/lap (or 400kW.s/lap).
Gasoline energy content is about 36MJ/l (or ~50MJ/kg).
This means that the race length should be 125 (50/0.4) laps for the energy from KERS to equalize that of 1kg of gasoline. It does not include efficiency of ICE and the KERS motor, but let's include it. Let's say (i'm speculating here) that ICE of modern F1 car has efficiency about 30%. A decent electric motor has efficiency about 80-90%, and if you include all storage and converter losses, let's assume it is 80%. This means that race length should be 125*0.3/0.8 ~ 47 laps for KERS energy to equalize that of 1 kg of fuel. So, if we assume average race length of 65 laps, then KERS car should have an advantage equaling 1.4kg of fuel at the beginning of the race (or 21g of fuel per lap). Pretty insignificant IMO.
I think that there are other factors, contributing to the fuel consumption - one should not take an engine itself, but an engine mounted in a specific car, using a specific gearbox, specific auxiliaries, with a specific aero, and most important - very specific engine mapping. Engine mapping does not come from the engine manufacturer (some initial mapping point should come from them though), as it depends not only on the engine itself, but on the gearbox, cooling, car aero, oil, etc.). Of course, the differences in mappings are minor, but in the end fuel consumptions are not too, and at the end all that matters is that final tenth or two at the end of the lap. And finally, the engines (however restricted and homologated) are not the same - this including intakes and exhausts.
good detail zmej!
and if you follow WB's link to the relevant thread, you'll find some graphs there that prove correct what you say.. different constructors with the same engines have very different fuel consumptions due to the variables you've mentioned.
there is a strong coincidence there tho.. The teams who ran KERS in 09, were the least thirsty out of those with the same engines. Trouble is they were the manufacturer teams too, so probably had better knowledge of their engines than the customer teams.
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The method was looking at actual non KERS consumption of the Ferrari and Renault engine. We agreed that there is potential for significant differences. It is also clear that the level of downforce will influence consumption. The cars with better downforce tend to run on higher throttle setting on average and consume more fuel.
Forget KERS. My query was not so much about whose engines have the best consumption but rather it concerned the various factors that contribute to efficiency given the very narrow parameters that are untouched by the regs. It is in this vein that I am seeking technical opinions from knowledgeable fans. Thank you.
Innovation over refinement is the prefered path to performance. -- Get rid of the dopey regs in F1
gcdugas wrote:...My query was not so much about whose engines have the best consumption but rather it concerned the various factors that contribute to efficiency given the very narrow parameters that are untouched by the regs...
Camshaft profiles can make all (well, not all, but may be half) the difference in the world. I think these are not regulated.
zmej wrote:Camshaft profiles can make all (well, not all, but may be half) the difference in the world. I think these are not regulated.
Yup, I mentioned that in my initial post (ramp angles). Also total valve mass because a heavier valve would require more "spring pressure" to close at the same rate as a lighter valve. Oil windage losses, water passage ways affect pumping losses in the cooling system as does oil passageway losses. Gearbox efficiency as well.
And then I asked... suppose Ferrari got all these as wrong as possible and Renault got these as right as possible.... what could the total effect be on efficiency? Could it be more than 2-3% given the similitude of all the spec'd areas within the FIA regs? And how likely is it that Ferrari would get it "that wrong" while Renault would get it "that right"?
Innovation over refinement is the prefered path to performance. -- Get rid of the dopey regs in F1
I don't think that particularly Renault got it wrong and Ferrari got it right. If you remember, last year Renault were down on power and were allowed to re-tune their engine so they could "catch up" with the rest. I think they are still a little down on power so they can have a little better fuel consumption. Why Red Bull would otherwise want to split with Renault to get Mercedes engines? Were they mad to split with the least fuel consuming engine? I think it was not just for the poor mid-season engine reliability.
I think also (although I could not possibly know for sure) the difference in power (and consequently in fuel consumption) is just in camshafts, intakes and exhausts, and, of course, in engine mappings. Maybe Renault just tuned their engine that it is less powerful but more fuel efficient - who knows? Don't think that oil/water/whatever pumping can have such an effect on fuel consumption. Valve mass? May be, who knows, but personally I think that with 18krpm limit different manufacturer engines valves are pretty similar (also in mass). Gearboxes may be different thing, though - gear ratios should be tuned to match engine performance. I mean, if you have better midrange torgue and less top-end power, you should have slightly different gear ratios than an engine with not-so-good midrange torgue and more top-end power - that (may be) could influence fuel consumption. Anyway, I think that gearbox efficiency as not much different for different teams.
And the only team that possibly got it all wrong was Honda - it was reported that their engines were about 60 bhp down in 2008. And what I'm saying is that it is pretty complex to answer your question - you may lose some power, but you may gain on fuel consumption and otherwise, so it is not just "got it all right" and "got it all wrong" - I think there is some "ideal" compromise to be found and may be Mercedes have found it - I don't know.
zmej wrote:I don't think that particularly Renault got it wrong and Ferrari got it right. If you remember, last year Renault were down on power and were allowed to re-tune their engine so they could "catch up" with the rest. I think they are still a little down on power so they can have a little better fuel consumption. Why Red Bull would otherwise want to split with Renault to get Mercedes engines? Were they mad to split with the least fuel consuming engine? I think it was not just for the poor mid-season engine reliability.....
Before everyone decided to ditch KERS (for 2010 only?) MB had a edge because their KERS system was greatly superior. Once you eliminate KERS the MB edge shrinks and Red Bull had much less motivation to change. If Renault was able to identify the cause of engine failures they can change that under the rules as well. While that is not all the story I am sure that Red Bull don't feel they are giving up a huge advantage by going with Renault again. They won the last three races using "worn" engines that they had to limp home so it couldn't be that bad.
Innovation over refinement is the prefered path to performance. -- Get rid of the dopey regs in F1
It is certainly not all in camshaft profiles, there are different coatings and surface treatments that can be used, different tolerances, different crankshaft designs, con-rods, piston ring technology, combustion chamber shape, injector technology, surface finish.
Pumps are a major contributor as well, especially when you have to run so many auxillaries. Can easily do a quick calculation based around 'PdV'
Mercedes' edge was not KERS, they have the best package by far in almost every factor. Do you think that Mercedes would sell their engine to what would become their greatest rivals in Red Bull? Especially since they lined up the purchase of Brawn GP ages ago.
There are so many things that cause the spread in engine performance, even down to the installation in the car, the way it's bolted in and becomes an integral part of the car. The means by which the block is stressed will alter factors such as bore distortion which influences both friction and wear properties.
If you want to make it a more or less pure case study, id recon that it could be best compairing the Red Bull-Renault RB5 and the Toro Rosso-Ferarri STR4.
Both cars had the same aero package, or should that be concept and philisiphy and can be more easily compaired for the 2009 season. That way we eliminiate the Ferarri and Renaults design differenced and also KERS at the same time.
Its a better raw test that way, arguably more accurate figures.
If i was to take the cross section for the 2009 engines id be taking the raw data from the following teams:
Renault RS27: Red Bull
Ferarri 056: STR-Ferarri
Mercedes FO108W: Brawn GP
Toyota RVX-09: Toyota
Id exclude the BMW power plant as its KERS contaminated from early season usage.
One factor I can think of would be something like the crankshaft journals and bearings. All engine manufacturers attempt to design bearings with as small a diameter as possible, to reduce friction. If, for example, Ferrari decided to design an engine with all main journals of the same diameter, and Renault designed their crank bearings in a stepped manner, in which the portions subject to lesser twisting forces would be smaller than those which experience larger forces, such as the bearings at the rear of the engine, where the final power is delivered.
Racing should be decided on the track, not the court room.
I think it would be suitable to begin by commenting on some of the regulations and misunderstandings regarding to these, and what they really are intended for:
Bore centers - F1 engines have a regulation that limits the choices when it comes to bore centers. The main purpose of this regulation is to prevent the engine manufacturers to produce 'ultra compact' engines where the distance between the cylinders are decreased as was the trend before this regulation was introduced. The regulation has no significant impact on fuel consumption.
Camshaft location - There are no restrictions regarding camshaft location.
Alloys - Certain materials are not allowed, such as alloys containing more than 5% beryllium, titanium aluminide and metal matrix composites. Certain parts are also restricted to a certain type of material, the crankshaft must for instance be of a Fe based material and the pistons must be Al based. The goal of these restrictions was to prevent certain development trends, such as expensive development regarding the use of titanium aluminide in valves and piston pins. What is often misunderstood though, is that most engines actually met these regulations even before they were introduced.
Bore stroke maximum ratio - There is no limit regarding the bore stroke ratio, however, there is a maximum bore of 98 mm specified. However, just like with the material regulations, most engines met this regulation before it was introduced. Indirect, the regulation put a limit on engine speed as the bore of the engines have increased over the years in order to make it possible to increase the revs. From the nineties the bore has increased from high 80'ties to high 90'ties; about a cm.
CoG - Introduced to prevent the use of for instance thinwall head castings. Thinwall cylinder head castings are problematic since a new head casting must be made as soon changes are made to the ports as there isn't enough material in the head to make changes to the ports without a new casting. They are also difficult from a casting perspecitve, and are subject to high material stresses. Without a limit of CoG a maximum weight for the engine would serve little purpose as the weight required would simply have been added as ballast at the bottom of the engine while the chase for grams at the top would go on
Essentially the same lubrication - There are no limits on either the lubrication system or the oil used. Each engine manufacturer have its own oil designed specifically for the engine in question.
Same fuel - Each engine have its own purpose designed fuel.
The regulations leave plenty of room for a manufacturer to design an engine as they choose, with the materials of choice. What mainly reduces the differences is the professionalism of the different engine manufacturers. They are simply too good to make any major mistakes in the engine design - unlike the past were teams with small resources could end of with an engine with more than 100 hp less than the competition. As a result, in the past it was common to see differences in lap times of several seconds.
Aside from differences in engine usage and power we can break down differences in fuel consumption to three parts: mechanical efficiency, thermal efficiency and fuel burned/fuel added.
Mechanical efficiency. I would suspect that the mechnical efficiency of a F1 engine, like most engines, are at full throttle around 90% at low engine speed decreasing to around 75% at peak power speed. The mechical efficiency is defined as BMEP/IMEP and include everything that is required to convert pressure inside the engine to useful work at the crankshaft. According to Cosworth the frictional losses of a F1 engine at 17,000 rpm are as follows: 47.3% bottom end mechanical, 26.7% pumping losses, 16.1% valvetrain, 4.0% churning bottom end, 3.5% eight scavenge oil pumps, 1.5% water pump and alternator, 0.9% oil pressure pump.
Thermal efficiency. This is related to heat and how it is used to increase the pressure inside the cylinder. There are many factors involved but the main factors are the heat release rate vs. piston movement and heat losses during combustion. Heat losses during combustion are also the main factor that determine the cooling requirement of an engine (combined with coolant temperature).
Fuel burned/fuel added. Not all fuel added can be fully burned and as such contribute to the heat release inside the engine. Some of the fuel is lost during gas exchange, and some fuel is added to provide cooling by vaporisation. Some fuel can also be added to make sure there is enough vaporised fuel before the combustion.
