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F1 2011: fuel flow rate limit, moving aero, auto compensation of lost downforce
(52 posts, started )
Ok dustin you can stop spamming now
faster camera's as in changing direction or faster capture rate?
Those new DSG style Semi Autos with insanely fast shift times.
dude that really stretching the truth. it's true that some of the first network protocol development was done by some guys who were at MIT in the 60's, but nothing much came of it until 1983, and the internet proper didn't come into existance until 1991.
and look how much damage weve done in 16 years.
Front axle huh
Yeah, the theories were around in the early sixties. In the 70's the US military started tinkering with it for satellites and advanced communication and it eventually made it into the commercial market.
I remember I've explained how energy recovery has real potential to work REALLY well even if the efficiency of the system from brake energy to propulsive energy was as low as 50% in some other F-1 related thread. Of course, it was under the assumption that all four wheels were used. And I also explained that if this energy could used to power the relatively underused front wheels (tractively speaking of course) corner exits would be much more efficient both in terms of speed and energy usage. And if implemented properly with drivers trained to fully exploit it, it'll mean that traction control would be unnecessary and possibly obsolete. With stickier slick tires and less downforce and thus drag, cornering and straight line speeds would remain extremely high whilst getting away with smaller and less powerful engines.
Ah well, one can only hope that the FIA doesn't make a joke out of this again.
Ah well, one can only hope that the FIA doesn't make a joke out of this again.
Who wants to bet?
50% efficiency sounds very ambitious to me given the fact you've got to try and get this energy across a racing car taking aero, weight and packaging into consideration in a pretty volatile environment.
Yah, so?
Actually, 50% efficiency is quite attainable if more direct energy conversion methods are used where instead of turning brake energy to electrical energy to be transfered and stored in batteries, one could transfer all that brake energy straight to mechanical energy in the form of ultra-high revving contra-rotating flywheels. But whether this system will be well developed enough in time to be implemented in F-1 cars 2-3 years down the road is very much an open question.
Energy recovery from the front axles is actually mandatory if the system is to work as well as it should and prove its worth. Even uber-high downforce F-1 cars do most of their braking work with the front brakes.
^^ I still think it's very ambitious seeing as a typical internal combustion engine has an efficiency of around 25% and I'd hazard a guess that an F1 engine is considerably less efficient and that's a type of power conversion that's had billions spent on developing it for over one hundred years 
If fuel flow is limited, then it may affect to max rpm too me thinks Or then they just make engines smaller.
Certain amount of air needs certain amount of fuel, if fuel is limited to 1 there must be less than 14.7 times of air or engine will self destruct and when you aim for power it is more like 12:1 or even 8:1 in turbos, so there is limit how much you can feed air to engine when fuel is limited and if you have more rpm you need more fuel, now what ever limit of fuel flow is that is going to be limiting rpm and also power you can get from engine, but this is neat limitation as now teams need to make engine more efficient and perhaps we see some new innovations that will someday come to civil cars too
Or then they just make engines smaller.Certain amount of air needs certain amount of fuel, if fuel is limited to 1 there must be less than 14.7 times of air or engine will self destruct and when you aim for power it is more like 12:1 or even 8:1 in turbos, so there is limit how much you can feed air to engine when fuel is limited and if you have more rpm you need more fuel, now what ever limit of fuel flow is that is going to be limiting rpm and also power you can get from engine, but this is neat limitation as now teams need to make engine more efficient and perhaps we see some new innovations that will someday come to civil cars too
Why on earth would you think a highly developed racing engine would be less efficient than typical?
The more efficient a naturally aspirated engine is, the more power it will produce. BSFC is actually a pretty decent indicator of the level of development. Lower being better. Plus, is it not obvious even now that if your engine uses more fuel than the competition's, you'll be at a great disadvantage in pit strategy?
-Engines don't self destruct when run lean. In the heyday of the large radial aircraft engine, lean of stoich operation for thousands of hours at high power levels was common. In the here and now, lean cruise is employed on a bunch of engines. More in Europe where fuel is expensive and low in sulfur.
-Best power occurs at a point called lean best torque. This has little to do with whether or not the engine is turbocharged. It is almost always in the 12.5-13:1 area. Turbo motors sometimes run more richly in order to help keep things like exhaust valves from burning up. 8:1 is just plain pig rich, at least with gasoline.
-For a variety of reasons, I think a fuel flow limit will encourage slower, larger displacement motors.
WRT the energy recovery, it will be interesting to see how the designers make trade offs. Will the unsprung weight disadvantage of a motor/generator at the wheel create a need for front axles leading to a motor/generator stuffed in the nose box? Or will designers leave the front of the vehicle alone and just recapture energy at the rear of the car?
IC Engines produce maximum power slightly rich, not slightly lean. This is partly due to combustion inefficiencies being conpensated by more fuel (they never manage to burn all the fuel, so if you provide the 'right' amount of fuel you don't BURN the right amount. Provide a bit too much and it ends up burning the 'right' amount = more specific output), and partly because of the evaporation of the fuel which can reduce in-cylinder temperatures which allow slightly more aggressive ignition timing, which can result in slightly more engine power.
There is no such thing as 'lean best torque'. You are thinking of MBT, which means Minimum Advance for Best Torque, and is the process where the ignition is retarded a couple of degrees to reduce knock sensitivity, but due to advance curve behavour only reduces power by a tiny percentage.
There is no such thing as 'lean best torque'. You are thinking of MBT, which means Minimum Advance for Best Torque, and is the process where the ignition is retarded a couple of degrees to reduce knock sensitivity, but due to advance curve behavour only reduces power by a tiny percentage.
Did I simplify it too much?
I was just correcting skiingman. What you wrote was a bit confusing to read, but (as far as I can tell) pretty close to accurate.
One question: Why must the energy recovery device be made as massive unsprung mass? There is no reason why that must be. The car will be trying to slow down and any device that captures this braking energy would actually reduce the burden on the brakes if its use is maximized, leading to less need for larger and thus heavier brakes. Assuming that electrical energy is used as the energy form to store and shunt around, why not simply build the heavier motor/generator body as the sprung weight and the relatively light
And when was the last time a modern F-1 car was seriously hampered by inertia of its drivetrain? If anything these things are still struggling with power-down at lower downforce speeds even with "only" 750hp, much less than the 900+hp of the V-10 era. If anyone has ever noticed the vast majority of engineering development with F-1 cars is through aerodynamics, to the point where other areas of development are usually compromised for all important aero. For instance, Ferrari made the compromise of reducing rear brake cooling to improve rear aero, and it paid off. Practically everyone runs zero-keel these days since the tradeoffs in suspension geometry are insignificant compared to the aero gains.
And 2nd, if you are really serious about energy recovery, to waste so much brake energy from the front wheels is going to be very counter productive. F-1 cars still achieve most of their overall deceleration via the front brakes despite of super high downforce and 3m long wheelbases coupled with LOW COG. 5gs of deceleration will see to that.
If you are going to correct me, you should, you know, be right.
Lean Best Torque means exactly what it says. Tends to be around .9 lambda. Yes, it is richer than stoich. Yes, you could have understood that if you read my first post. Rich Best Torque is a couple points richer and is as rich as you can go without power falling off considerably. I've never seen exact definitions of these, but they describe an area in the lambda/torque curve that is generally very flat.
Engines do produce their minima for BSFC when lean of stoich. 16:1 or so. This has been proven again and again both empirically and in the theory, and I can direct you to papers on the subject written in the 1920's if you so desire.
MBT has nothing to do with "retarding timing a few degrees." MBT is exactly what it says it is, minimum timing advance for best torque, which varies dramatically with many factors to produce a theta PP that is essentially static for a given engine design.
Do yourself a favor and go type these terms into Google. Read a little. Sir Harry explained these simple topics before your parents were born.
Good luck building a motor/generator that can convert energy from a rotating shaft into power with the kind of packaging and mass efficiency a carbon brake has. Its a formidable engineering challenge. I'm guessing the weight will end up sprung, but I haven't looked at it in detail. I was assuming electricity as the medium as well, but on second thought I think mechanical or hydraulic systems will be better suited.
I would agree, except for a couple things:
-As you've stated, aero owns all other disciplines.
-There is a gigantic amount of energy dissipated by the rear brakes alone, forgetting for a moment about the even greater portion up front.
My intuitive guess is that any energy recovery system is going to be snagging the low hanging fruit it can without compromising the aero package. Thus I start to find new axles at the front and a compromise nose somewhat less likely than a system that packages at the end of the vehicle where there are already shafts in place. Could be completely and utterly wrong about that, especially if someone decides all wheel drive is a worthy goal/within the rules.
Erm, I know (and wrote in my post) that peak power is obtained at richer than stoich. A MBT IS about retarding it a couple of degrees (albeit scientifically).
There is a curve. On that curve you can have best torque, or by retarding a little bit you get a tiny decrease in torque but a large safety margin from knocking. Obviously you don't just find best torque and 'retard a couple of degrees', you look at probably hundreds of graphs to find out how much in any given circumstance. The figure for MBT at a given RPM will vary with load, ambient temperature etc. Why do you think cars have sensors for the above, and knock sensors. It's not just to make it more fun for the engineers.
I never argued about BSFC being richer than stoich.
I think YOU should type the terms into Google, and THEN do it in real life. As nice as 100% theory is, that's not actually how it's done in reality, as everything is a compromise.
There is a curve. On that curve you can have best torque, or by retarding a little bit you get a tiny decrease in torque but a large safety margin from knocking. Obviously you don't just find best torque and 'retard a couple of degrees', you look at probably hundreds of graphs to find out how much in any given circumstance. The figure for MBT at a given RPM will vary with load, ambient temperature etc. Why do you think cars have sensors for the above, and knock sensors. It's not just to make it more fun for the engineers.
I never argued about BSFC being richer than stoich.
I think YOU should type the terms into Google, and THEN do it in real life. As nice as 100% theory is, that's not actually how it's done in reality, as everything is a compromise.
No, it isn't. MBT is exactly what it claims to be. It varies with many factors but the result is the same, location of peak pressure at the optimal crank angle. The location of the detonation margin may be advanced or retarded from MBT depending on design and conditions...often by far more than "a couple degrees".
You don't "look at hundreds of graphs". There is no need to do so when you have a test rig with direct measurement of theta PP. Real time measurement of torque and cylinder pressure has been practiced since at least World War II, again...before you were born. In practice, you adjust ignition timing in real time until you have achieved your goal. Unless you don't have the appropriate hardware and you aren't clever enough to build your own.
No, you made a really ignorant assumption about my post. Read it over until you understand it. I was explaining that the minima for BSFC is lean of stoich, and that engines have been run this way for longer than you've been alive. I made these comments because someone expressed the misconception that engines automagically blow up when run lean. Lean of stoich is where best economy is found. Lean Best Torque which is rich of stoich is where best power is found.
I have done this IRL, champ.
I'm working on a closed loop ion-sensing ignition controller -from scratch- for my project car at the moment. Quite an amusing summer project.
You are a pretty cocksure dude. You aren't even familiar with the basic terminology (worse, you called me wrong about it rather than consulting any number of textbooks...or Google) and you post as if you actually have experience in the field.
Yes, it might be more than a couple of degrees, but it's a figure of speech. It's rarely going to be more than 5 degrees from 'Best Torque'.
Or perhaps aren't rich enough. I know for a fact that Lotus, for example, didn't have the ability to measure theta PP in real time until the 90s. Lots of engine manufacturers haven't had that ability until fairly recently. Cylinder pressure and torque are of course a requirement, and I think every engine builder has had this ability for a long long long time. To set the ignition timing you have to know what the curves are around best torque, which is the graphs you are looking at. You also need to know, or be able to estimate, the knock limit. You don't just plug in a computer and let it magically sort it all out - you need to see all the data. And before mappable ignition became as advanced as it is now, then the compromises were a lot bigger.
Best torque is found at best torque. Lean of best torque is where you get a small decrease of torque (perhaps negligable), but a large improvement in BSFC. To state that best torque is found at LBT is simply wrong.
So have I. Admittedly on older engines, without mappable ignitions.[/quote]
Sounds interesting. I'd love to see some of your work.
Am quite familiar with basic terminology, thank you. And I have some experience in the field. Maybe not as much as you, and maybe my interests lie in different aspects of it. But I can assure you I completely understand what you've been saying, and I completely agree that lean engines don't suddenly blow up - it would make lean-burn engines a pretty big disaster if it were true.
Last time I checked the only serious factor regarding how much horsepower you get from the engine for any given fuel/air ratio and ignition mapping is how much cash you spend sorting it out.
edit: £5 on tristan, because he's british.
edit: £5 on tristan, because he's british.
F1 2011: fuel flow rate limit, moving aero, auto compensation of lost downforce
(52 posts, started )
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