Technical Regulations for 2009-2015

[xpensive]

"Green Car Cogress", with Mike Milliken, eh? I wouldn't take anything from that source to the bank, he wouldn't know the difference between kW and kWh anyway! Just another opportunistic journo, first IT and now electric cars.

[WhiteBlue]

The KERS unit used by McLaren features custom lithium-ion power cells developed by A123Systems that offer more than 20,000 W/kg, according to Ric Fulop, one of A123Systems’s co-founders.

There are a number of facts that can be checked and that are accurate. MercedesHighPerformanceEngine Ltd. was and remains one of the biggest customers of A123. The 2009 annual report of MBHPE Ltd. and of A123 confirm that. I believe that the Merc SLS E-Cell is also working on A123 batteries. You get an impression what is possible.

[youtube]http://www.youtube.com/watch?v=zkCO-TjoQu0[/youtube]

From other sources it is also clear that A123's proprietory nano phosphate lithium ion technology is a big break through in the battery market. If you google Ric Fulop you find numerous references that confirm him as co-founder of A123 and their long time business development head. So I'm inclined to believe the quoted figure of 20 kW/kg is accurate.

As I have said it doesn't mean that the power/weight ratio is the determining factor for the battery weight. It just means that you can charge and draw power on that battery with a very high rate. The weight will probably be determined by the capacity/weight ratio. We do not have reliable figures for that, but I believe from the Merc 2009 KERS design that it is better than 45 kJ/kg. This would indicate a maximum battery weight of 49 kg for 2.2 MJ.

[xpensive]

I believe things are higly dependant on the detailed regulations, if you are only allowed one 30 second burst of 110 kW (where to use that btw?), 3.3 MJ, surely the energy density will be the limiting parameter for the battery.

But if you are allowed charge/discharge at your leisure up to a total of 3.3 MJ per lap, I guess power-density will be more important?

[WhiteBlue]

I think they would be mad to require a single boost. The 2009 and 2011 regulations did not have that. They can boost as often as they want until the lap load is exhausted.

So for 2013 if they have 2200 instead of 400 kJ a single KERS boost would not make any sense at all.

[timbo]

We have already gone through the exercise of calculating the specs and found that the power peaks under breaking where you need approximately 200 kW. From that point of view battery weight should be 10 kg. But I doubt that power is the decisive design item for weight. I reckon it will be capacity. It would be good news if a 2.2 MJ battery would be available at 25-30 kg. It would be even better if they stop the stupid push to pass legislation and go to permanent dual torque. The battery would not have to be designed to hold the whole charge of one lap in that case.

Energy density is not a problem actually. Commercial products are quoted around 540-750 kJ/kg. It is power density, which determines how fast you can charge or discharge battery that is limiting factor.
And heat too.

[timbo]

Timbo, I quoted my source, perhaps you can share your source will us as well. I do not have an agenda, I just share what I read. If the guy, a cofounder of the company, is misinformed, then so am I.

I didn't criticize your quote)
It was interesting to know where the info came from, as the figure is a bit higher than what I heard.

Oh, and I'm not a University professor too))) OTOH I have PhD in Chemistry and do work in University))

[Scotracer]

We have already gone through the exercise of calculating the specs and found that the power peaks under breaking where you need approximately 200 kW. From that point of view battery weight should be 10 kg. But I doubt that power is the decisive design item for weight. I reckon it will be capacity. It would be good news if a 2.2 MJ battery would be available at 25-30 kg. It would be even better if they stop the stupid push to pass legislation and go to permanent dual torque. The battery would not have to be designed to hold the whole charge of one lap in that case.

Energy density is not a problem actually. Commercial products are quoted around 540-750 kJ/kg. It is power density, which determines how fast you can charge or discharge battery that is limiting factor.
And heat too.

Indeed. That is the issue with diesel.

[WhiteBlue]

I have thought about the way F1 is going to restrict fuel use from 2013 onwards. Most people have followed Autosport's interpretation of a technical fuel flow limit.

In a bid to further increase F1's green credentials, teams are also keen for there to be a fuel flow rate limit - which will ensure the engines are economical.

The Autosport interpretation is based on an original quote by Sam Michael.

Rather than dump as much fuel in as we can at the moment, there will be a fuel flow metre – so you won’t be able to blow more than a certain amount of fuel. It is a good chunk less than we had at the moment.

When I read this carefully I could also come to the conclusion that Michael talks about a flow meter on the pump when the fuel is filled into the car. He talks about a certain amount of fuel that can be used and not about a flow rate to the engine. I would much prefer that solution and we would have to wait and see what they decide.

[aral]

I am totally lost on this "discussion", but I understood that a spec KERS was to be supplied, so all cars will have access to the same benefits.
But what is of interest is BHP. I was watching a programme about the Veyron last night, and when testing the engine, it was mentioned that it gave 1000BHP, but the narrator went on to say, that the engine actually produces 3000BHP but 2000BHP is lost through heat! Can this be correct? And if so, surely great gains could be made by efforts to limit heat loss?
Can someone enlighten me, please?

[timbo]

But what is of interest is BHP. I was watching a programme about the Veyron last night, and when testing the engine, it was mentioned that it gave 1000BHP, but the narrator went on to say, that the engine actually produces 3000BHP but 2000BHP is lost through heat! Can this be correct? And if so, surely great gains could be made by efforts to limit heat loss?
Can someone enlighten me, please?

That would mean efficiency of 33% not that bad. Otto-cycle engines are quoted around 35%.
Some effort is indeed spent on creating technologies for improving thermal efficiency, e.g. turbo-compounding or adiabatic engines and also HERS (H for heat).

[Scotracer]

I am totally lost on this "discussion", but I understood that a spec KERS was to be supplied, so all cars will have access to the same benefits.
But what is of interest is BHP. I was watching a programme about the Veyron last night, and when testing the engine, it was mentioned that it gave 1000BHP, but the narrator went on to say, that the engine actually produces 3000BHP but 2000BHP is lost through heat! Can this be correct? And if so, surely great gains could be made by efforts to limit heat loss?
Can someone enlighten me, please?

That means that the total amount of energy within the fuel is effectively 3000BHP but it can only transform 1000BHP of that it in to usable work. As Timbo said, 35% is about all you can get out of a spark-ignition engine these days.

[WhiteBlue]

I am totally lost on this "discussion", but I understood that a spec KERS was to be supplied, so all cars will have access to the same benefits.
But what is of interest is BHP. I was watching a programme about the Veyron last night, and when testing the engine, it was mentioned that it gave 1000BHP, but the narrator went on to say, that the engine actually produces 3000BHP but 2000BHP is lost through heat! Can this be correct? And if so, surely great gains could be made by efforts to limit heat loss?
Can someone enlighten me, please?

Kinetic energy recovery (KERS) is supposed to become a source of competitive advantage in 2013 again. So standardized KERS would not make much sense. It is more probable that a sales price cap will be placed on engines with KERS or single KERS systems.

Re the Veyron program you are probably aware that all engines have a very limited relation between the energy that is fed with the fuel and the work that the engine produces on the crank shaft. Work and energy are measured in the same physical units (kJ or MJ). If you look at the energy or work per time you arrive at power which is both measured in kJ/s or kW. So the chemical energy of the fuel goes into the engine at a certain rate which we can measure in kW. The engine produces work and heat at a certain rate which we can also measure in kW. If you compare the energy flow in the fuel and the mechanical power produced by the engine you find the efficiency which is typically between 20 and 30 %. Naturally the difference to 100% is the heat that is discarded from the engine cooling and the exhaust gases.

The efficiency of an internal combustion engine depends of many different design parameters. If you add more friction by many moving mechanical parts your efficiency is worse. This why fewer cylinders of similar design quality usually produce less thirsty engines.

If you restrict the air flow by smaller valve cross sections or by throttling the air that goes into the engine you increase the aerodynamic pumping losses of the engine and you get a worse efficiency. This is why racing engines from 1912 and production engines from the seventies have used four valves to get maximum cross section. This is also the reason why variable valve timing and lift is going to replace throttle plates in petrol engines.

If you cleverly design a combustion process that burns all the fuel in the air fuel mixture (stoichiometric combustion) your efficiency improves compared to a process that blows unburned fuel from the exhaust.

If you capture some of the heat and pressure in the exhaust gases by a turbo charger or turbo compounder you avoid some of the losses and improve efficiency. Same is true if you manage to turn some of the rejected heat into mechanical work by an additional heat/work machine (HERS) like a Rankine cycle.

[timbo]

Naturally the difference to 100% is the heat that is discarded from the engine cooling and the exhaust gases.

Not only. Carnot theorem puts a limit on the fraction of energy you can convert from heat to work. Even if you have "perfect" engine that does not need cooling and that produce exhaust gases of room temperature and atmospheric pressure and has zero mechanical losses, you would not reach 100% efficiency.

[Scotracer]

Naturally the difference to 100% is the heat that is discarded from the engine cooling and the exhaust gases.

Not only. Carnot theorem puts a limit on the fraction of energy you can convert from heat to work. Even if you have "perfect" engine that does not need cooling and that produce exhaust gases of room temperature and atmospheric pressure and has zero mechanical losses, you would not reach 100% efficiency.

Off the top of my head, Carnot is around 42%?

[WhiteBlue]

You can get around Carnot by using multi stage machinery as you do in stationary power generation.