Monday, 26 September 2011

The emergence of a new technology.

I have mentioned before that I am a fan of (and a subscriber to) the French language ‘Le Mans Racing’ magazine - and an article caught my eye in the most recent edition, that I thought might interest my readership here. It is all about the emergence of LED headlamp technology, and I translate (and paraphrase) it below:

It was well-publicised by Audi, praised by the drivers who used it and also criticised by GT drivers who spoke of being blinded, but LED headlights hit the headlines in the recent 24 hour of Le Mans. They also achieved an historic victory.

Since their invention, car headlights have always evolved - from traditional tungsten bulbs to halogen. In both cases though, the same principle is used - a filament (wire) in a glass bulb. For a few years, xenon headlights have become more widespread. The bulb consists of two electrodes sitting in xenon (a gas) under high pressure. An auxiliary system that generates a high voltage of 20,000 volts starts the illumination of the gap between the two electrodes; then the voltage is reduced to 85 volts as soon as the beam is started.

A few years ago LED headlights appeared in concept cars at shows and exhibitions, giving designers greater freedom - enabling them to design cars that did not have merely round headlamps. And this year, for the first time, LED headlights appeared in competition, fitted on certain cars in the 24 hours of Le Mans. LEDs (Light Emitting Diodes) consist of a semi-conductor which converts electric current directly into light, and a lens ensuring that the light forms a beam. One can also put a mirror behind the LED (like in a traditional headlight).

There are several advantages.
The delay to illuminate an LED is extremely short - between 2 and 10 milliseconds - this is especially useful when flashing headlights, compared to 150ms to 300ms for halogen lights.

Since about 80% of the energy is converted to light, compared to 20% for traditional bulbs (the rest is converted to heat), headlights with equal brightness consume much less current.

The temperature of the emitted light is 6000 Kelvin, which amounts to a very white light, comparable to daylight. This is identical to that produced by xenon headlights (but compares to only 3000K for halogen, which are slightly yellowish). But the light is more diffuse, less violent than xenon and the lighting is more “comfortable”, and permits better distinction of the features of the road. In fact, halogen headlights produce a luminosity of 1500 lumens, xenon bulbs about 3200 lumens and a headlight with 6 LEDs produces about 1500. The light produced is therefore less bright than xenon, and therefore induces less glare.

The additional weight of xenon lights is also an important consideration - the combination of the weight for the projection equipment and the bulb itself is around 1.1 - 1.2kg, compared to 650g for a headlight consisting of 9 diodes. The integration into the bodywork is also simpler: no big projector to install, less heat generated, a flexible and adaptable shape along with a reduced volume; and it is the last two reasons that are important in racing circles.

In summary, then, LEDs are light, easy to install, use a little less current than xenon and a lot less than halogen and produce a less violent and a slightly less glare-inducing light than xenon but more homogenous and comfortable than halogen.

Victory at Le Mans
Only three models of car - all LMP1 - were equipped with LED headlamps at this year’s 24 hours. Of course there were the three Audi R18’s and in addition two of the four Oak Pescarolos. The 2011 version of the Peugeot 908 had a mixed lighting system, with a single LED lamp situated above the more traditional xenon lights. Although the LEDs of Audi and Oak came from the same supplier (Osram), the installations were completely different on the two cars. The implementation on the Audi was specific to the R18. On each side of the car was a double vertical beam, with 5 diodes on the outside of the headlamp and three on the inside. Behind these diodes were placed many mini-reflectors. Only the outside part was illuminated during the daytime.

Oak Racing replaced the three traditional Xenon headlights on each side of their Pescarolos by three LED
projectors, supplied by the RaceTech Harnessing. One of these had six diodes, and the other two had just three, all equipped with lenses to focus the light.

In the final classification, with one Audi followed by three Peugeots, the four first positions were occupied by cars using LED headlights.

Finally, note that this technology, which is already present on the rear lights of some road cars, will be rapidly used for road headlamps - and this has already been authorised by the EU.

Apologies for the slightly clunky English - that’s why I am not a professional translator. In any event, I found it interesting, as is RaceTech Harnessing’s website: I get the impression that in a few years' time we will look back on 'bulb' technology as something very quaint. Remember when number plates used to be black and white?

Monday, 19 September 2011

Silverstone 6 hours - 30 hours at Becketts

Readers of this blog don’t come here to read race reports or the latest news from the sportscar scene. So if that’s what you’re after, I suggest you read elsewhere. What I try to bring you, dear reader, is an alternative view: occasionally a deeper view, but in any case something that you can’t read elsewhere. For that reason, I would like to share my experiences of being at Silverstone for the 2011 ILMC/LMS Six Hour race. And I apologise that it’s taken me so long to get this out, but the demands of work and home life have been particularly great recently.

Anyway, the organisers asked John Hindhaugh and his crew from to provide PA commentary for the whole meeting, including practice, qualifying and all the support events. This is just what I used to do, years ago, before family pressures came along, and hence I was asked to be at the Becketts commentary box from nine o’clock on Friday morning until the end of track action on Sunday evening.

OK, so I was allowed out to attend the teamDOT AGM on Friday evening, and to get my meals (thanks to Carlo and his team at the Smoking Dog). And thanks too to Gail at Linford Stables, where I spent very quiet and comfortable Friday and Saturday nights. But other than that, I was at my post throughout - and I have to say, I was very happy to be there. One of the drawbacks about commentating these days is that I often find myself removed from ‘the action’. I get a great view of the start finish straight at Le Mans, and can see wonderfully into the pits, but I really miss not being able to see cars actually racing, in the same way that spectators can. Watching on a TV when you’re there misses the point, to my way of thinking.

The view from the box at Becketts is outstanding. I could see the cars through Farm Corner (turn 2), Village, The Loop, Aintree and out onto the Wellington Straight. Then they went out of view at Brooklands, Luffield and the National Straight. But I could see them again out of Copse, through the astonishing Becketts esses before they went out of sight again. From the back rows of the grandstands (that were open to the public) either on the outside of Becketts, or on the outside of Village, the view would have been even better.

Throughout the weekend, a steady flow of spectators trudged past, on their way to other viewing locations, but they all had smiles on their faces. Less cheerful were the media, team and VIP types who had to catch the bus from Silverstone’s new nerve centre at The Wing to the car parks at the other end of the estate. What I cannot understand is why buildings such as The Wing, while they are impressive visual edifices architecturally, do not provide either a media centre with windows, or commentary boxes with anything like a decent view of the circuit. Even though Hindhaugh’s box overlooked the start finish area, there was no view of the pit lane, and in order to watch cars come out of the final corner one had to climb up onto the table in front of the commentary box window. If I had been trying to do a manual lap chart from there, it would have been nigh on impossible.

Apart from the logistics of getting from one place to another, I think Silverstone has a fine circuit these days though. Fast, sweeping corners in abundance and a couple of tight, technical bits to demand compromises to set-up and precision in driving. It is a good, wide circuit where overtaking is possible. And I was amazed at how quickly it dried out after a couple of rain showers that crossed the circuit over the weekend. The pit garages are cavernous, although not suitable for a fifty-car entry, which really needs more garages of a smaller size. As for the pit lane itself - it is a curiosity: very wide, with a huge expanse of grass between the pit lane and the pit wall; and seemingly descending into a trench at the far (pit-out) end as it strives for a level track surface where the contours around it are climbing upwards. I didn’t measure it, but it seemed to be to be half the length of the pit-lane at Le Mans.

Now is not the time for ‘what-might-have-been’, but I just wonder if the possibility was considered to build the pits and have the start/finish on the Wellington Straight (formerly known as the National Straight)?

Anyway, what of the race itself? It was probably not a classic, although most of the ingredients were there to make it one. What impressed me most of all was how close the Audi and Peugeots were. In a sense it was the perfect race - the difference was not in the cars, but in the drivers: having to make several overtaking decisions every lap; evaluating risk, judging closing speeds, avoiding collisions. And the difference, as far as the outright result was concerned, was down purely to those factors: not mechanical breakdowns, or weather, or safety car interventions.

Just how close the top four works diesels were is shown in the following table. This shows the average lap time for each driver, ignoring full course caution periods and those laps where accidents, spins or other incidents occurred, and ignoring time spent in the pits.

For comparison, I also show the best lap for each driver, although note that for the purposes of this I include ‘in laps’, which at Silverstone in its current configuration, is shorter than the normal racing lap. An asterisk shows if the lap was an ‘in lap’ (i.e. it terminated in the pit lane).

Was Peugeot a worthy winner? Or did Audi throw away a chance of victory? Let’s have a look at ‘Time spent in pits’ for each of those cars: The number in brackets for Audi no. 2 and Peugeot no.8 includes an estimate of the time lost on the track while recovering from their respective off-track excursions. In McNish’s case, this was around 58s lost on a slow lap back to the pits; for Montagny I have added 7m 15s while Franck (and the marshals) man-handled the car out of the gravel at Copse Corner.

At the end of the race there was 1m 29.763s between the no 1 Audi of Bernhard/Fässler and the no 7 Peugeot of Bourdais/Pagenaud. The difference in time spent in the pits was 1m 03s. Bernhard lost about 17s when he spun on lap 40. So even allowing for this, the Peugeot seems to have deserved its victory - although that is not to say that had certain events turned out differently, that we could have had a different result.

What I find puzzling, but what time has not allowed me to find out, is why the delayed Peugeot of Montagny / Sarrazin and the delayed Audi of McNish / Kristensen finished three laps apart, when the amount of time that each lost was nearly the same. It could be a glitch in my data, but I haven’t had the opportunity to dig more deeply.

For those whom it interests (are there others out there like me?) full details of the pit stops for the four diesels are as follows:

Peugeot no. 7 - Start driver Sebastien Bourdais.
Stop 1 (lap 25) Fuel only - 59s
Stop 2 (lap 53) Driver change: Bourdais to Pagenaud; fuel; tyres - 1m 27s
Stop 3 (lap 79) Fuel only - 1m 00s
Stop 4 (lap 105) Driver change: Pagenaud to Bourdais; fuel; tyres - 1m 27s
Stop 5 (lap 132) Fuel only - 1m 00s
Stop 6 (lap 159) Driver change: Bourdais to Pagenaud; fuel; tyres - 1m 29s
Stop 7 (lap 185) Fuel only - 35s

Audi no. 1 - Start driver Timo Bernhard
Stop 1 (lap 25) Fuel only - 58s
Stop 2 (lap 53) Driver change: Bernhard to Fassler; fuel; tyres - 1m 24s
Stop 3 (lap 79) Fuel only - 58s
Stop 4 (lap 105) Driver change: Fassler to Bernhard; fuel; tyres - 1m 26s
Stop 5 (lap 131) Driver change: Bernhard to Fassler; fuel; tyres; rear bodywork - 2m 27s
Stop 6 (lap 157) Fuel; change front left tyre - 1m 09s
Stop 7 (lap 183) Fuel only - 38s

Audi no. 2 - Start driver Allan McNish
Stop 1 (lap 23) Fuel; tyres; inspect damage after contact - 1m 33s
Stop 2 (lap 24) Fuel; front left tyre; suspension; bodywork - 12m 53s
Stop 3 (lap 50) Fuel only - 58s
Stop 4 (lap 77) Driver change: McNish to Kristensen; fuel; tyres - 1m 28s
Stop 5 (lap 104) Fuel only - 59s
Stop 6 (lap 131) Driver change: Kristensen to McNish; fuel; tyres - 1m 25s
Stop 7 (lap 158) Driver change: McNish to Kristensen; fuel; tyres - 1m 30s

Peugeot no. 8 - Start driver Franck Montagny
Stop 1 (lap 9) Accident repairs: front left; fuel; tyres - 7m 58s
Stop 2 (lap 37) Fuel only - 57s
Stop 3 (lap 63) Driver change: Montagny to Sarrazin; fuel; tyres - 1m 23s
Stop 4 (lap 89) Fuel only - 59s
Stop 5 (lap 115) Fuel; tyres - 1m 26s
Stop 6 (lap 140) Driver change: Sarrazin to Montagny; fuel; tyres - 1m 22s
Stop 7 (lap 159) Fuel only - 49s

I'm back at Silverstone again in a couple of weeks - for the Britcar 24. Should be fun - I'm looking forward to it. Hope to see you there.