Vodaphone McLaren Mercedes MP4-24

[xpensive]

I think you are missing the point kilcoo, 60 kW is peanuts in the context, when breaking power is 1000 kW?

[kilcoo316]

I think you are missing the point kilcoo, 60 kW is peanuts in the context, when breaking power is 1000 kW?

But its not an instantly controllable 60kW... and the cars are sensitive to rear lock-ups (I do appreciate that it is only 6% of total braking force... but that is also around 13% of the rear brake force - on a 55:45 split)


Oooohhhh, heres a thought.


Some of the drivers downshift to balance the car (ok, the better ones do)... using the KERS to add rear braking retardation when the engine revs drop (between shifts) would offer a way of keeping the effective brake balance more consistent.

It would be a dynamic charging of KERS, and makes much more sense than simply on/off.

Whats the bets KERS eventually becomes part of the differential settings used for car balance...

[Metar]

That'd be a different (and likely legal) way of solving it. I thought, if KERS wasn't time-restricted, that they could use it to "overpower" the rear brakes to prevent them from locking - like the engine-braking of yore.

Also, can they charge KERS while not braking? Say, use it as a traction-control system by charging the excess power from the engine into the batteries?

[xpensive]

Surely you could control the generator-load electronically and couple it to the brake-pedal somehow?

[CMSMJ1]

my take on the KERS is different to you guys. Why do you think they are using it in conjunction with the rear brakes? My thoughts are they they take the "charge" from the crankshaft and it is only the difference in engine braking that is affected. As it stands they can use a very small (relative to the output boost and the rear braking forces) chargerate to keep the system topped up. the device is never really empty..just that the button doesn't trigger it any more.

I don't treat it like a battery that is getting fully discharged when the 6.6s has ran out. More like that between presses it is recharged.

I hope you get what I mean...at work, no time for an essay!

[timbo]

Rules are pretty strict dealing with brakes. But I guess as most cars have adjustable brake balance they can have additional KERS setting.

[Metar]

Rules are pretty strict dealing with brakes. But I guess as most cars have adjustable brake balance they can have additional KERS setting.

I recall reading an article in Racecar Engineering explaining how Ferrari had a system, in 2007, that varied the brake-bias in order to adapt to changing downforce and weight-shifting..

Would that system still be in place? Or even legal?

[timbo]

Rules are pretty strict dealing with brakes. But I guess as most cars have adjustable brake balance they can have additional KERS setting.

I recall reading an article in Racecar Engineering explaining how Ferrari had a system, in 2007, that varied the brake-bias in order to adapt to changing downforce and weight-shifting..

Would that system still be in place? Or even legal?

From spygate hearings it was revealed that they had some mechanical system that delayed rear axle braking.

[Metar]

Yeah, that - only if I recall correctly, it was a system that slowly removed rear brake-force? After all, at speed you have lots of rear downforce, but as you slow down, the "centre of forces" moves forward (less downforce, car tilts forward under braking)?

[DaveKillens]

The regulations about brakes is very specific and fundamental.

ARTICLE 11 : BRAKE SYSTEM
11.1 Brake circuits and pressure distribution :
11.1.1 With the exception of a KERS, all cars must be equipped with only one brake system. This system must comprise solely of two separate hydraulic circuits operated by one pedal, one circuit operating on the two front wheels and the other on the two rear wheels. This system must be designed so that if a failure occurs
in one circuit the pedal will still operate the brakes in the other.
11.1.2 The brake system must be designed in order that the force exerted on the brake pads within each circuit are the same at all times.
11.1.3 Any powered device which is capable of altering the configuration or affecting the performance of any part of the brake system is forbidden.
11.1.4 Any change to, or modulation of, the brake system whilst the car is moving must be made by the driver's direct physical input, may not be pre-set and must be under his complete control at all times.

KERS cannot input into the braking circuit.

There is nothing forbidding when and where the KERS recharges. Most likely, if the system is aware that the battery level is anything but full, it will direct the KERS to charge the system on the next braking cycle(s). So basically, KERS is kept topped up as much as possible. KERS control tracks how much time and energy is allowed each lap, and rations out power as applicable. If Hamilton presses his magic button but the KERS has already discharged it's allowed maximum energy, then it just won't allow anything to happen, until the car crosses the start line and another cycle begins.

[wrcsti]

my take on the KERS is different to you guys. Why do you think they are using it in conjunction with the rear brakes? My thoughts are they they take the "charge" from the crankshaft and it is only the difference in engine braking that is affected. As it stands they can use a very small (relative to the output boost and the rear braking forces) chargerate to keep the system topped up. the device is never really empty..just that the button doesn't trigger it any more.

I don't treat it like a battery that is getting fully discharged when the 6.6s has ran out. More like that between presses it is recharged.

I hope you get what I mean...at work, no time for an essay!

I'm quite surprised to know they use batteries and not super capacitors as used in battery powered RC cars for a automatic boost out of corners.

[RacingManiac]

there is a limit though as to how much energy KERS can store, and there will probably be time when you aren't using the KERS, and it is topped off and can't store more....

[Fil]

"If we had been content as a race team to have had extremely poor performance over the first four races and concentrate on a big development for Spain, then perhaps we could have made a bigger step forward. But it is a weakness and a strength that we are a race team and we throw everything at every weekend, and it is not in our make up or temperament to be occasionally that measured. Sometimes it gives you an overall development momentum to be improving race-by-race, but I acknowledge that approach can be detrimental in the longer term."

Whitmarsh on McLaren's development cycle decision.
its odd that he admits they would be quicker if they waited on developing one big upgrade, this they have lost out on for 13 points.

did they choose the right development pathway?

[Giblet]

Capacitors can get very large, and their power density vs energy desnity is on opposite ends of the scale.

From what I've read, traditional capacitors are too large to effectively replace a battery, but this was interesting...

"In August 2007, a research team at RPI developed a paper battery with aligned carbon nanotubes, designed to function as both a lithium-ion battery and a supercapacitor (called bacitor), using an ionic liquid, essentially a liquid salt, as the electrolyte. The sheets can be rolled, twisted, folded, or cut into numerous shapes with no loss of integrity or efficiency, or stacked, like printer paper (or a Voltaic pile), to boost total output. Further, they can be made in a variety of sizes, from postage stamp to broadsheet. Their light weight and low cost make them attractive for portable electronics, aircraft, automobiles, and toys (such as model aircraft), while their ability to use electrolytes in blood make them potentially useful for medical devices such as pacemakers. In addition, they are biodegradable."

This could be used to mold your batteries/caps into the chassis, or even body shell.

[DaveKillens]

"If we had been content as a race team to have had extremely poor performance over the first four races and concentrate on a big development for Spain, then perhaps we could have made a bigger step forward. But it is a weakness and a strength that we are a race team and we throw everything at every weekend, and it is not in our make up or temperament to be occasionally that measured. Sometimes it gives you an overall development momentum to be improving race-by-race, but I acknowledge that approach can be detrimental in the longer term."

Whitmarsh on McLaren's development cycle decision.
its odd that he admits they would be quicker if they waited on developing one big upgrade, this they have lost out on for 13 points.

did they choose the right development pathway?

Compare their results to BMW, who decided to follow the other path. They looked strong in Australia, but never developed their car at all in the next three races. In points, Mclaren have 13 while BMW posess 4. Those only 4 points were captured by Heidfeld in Malaysia, due not to a superior car, but superior tactics, and luck in being in the right place at the right time when the rain came. Currently BMW drivers are nervous and panicking (both drivers had contact with others in the race in Bahrain), and it may be difficult to return to the culture of being in control and posessing a winning habit and mentality. Meanwhile McLaren have gathered points even though they are fighting for a mid-field position.
What good is waiting to get a better car when the team winds up in turmoil and lacking confidence? And even if their upgrades launches their car to the top in performance, they have a lot of points to make up.
It's not about who's got the best car, but who has the most points at the end of the season.