Renault break cover on Red Bull engine mapping intrigue
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Posted By: James Allen  |  27 Jul 2012   |  10:01 pm GMT  |  34 comments

Renault Sport’s Rob White has put out a document this evening which looks at the Red Bull engine mapping intrigue of the last week and explains Renault’s side of the story.

Following intervention from the FIA technical staff in German and a subsequent clarification of the rules, Renault has been obliged to go back to pre-Germany torque maps on the Red Bull cars.

Here White explains what the fuss is all about:

What is a driver torque map?

The driver torque map represents the torque requested by the driver as a function of engine speed and accelerator pedal position.

What is an engine torque map?

The engine torque map represents the torque delivered by the engine as a function of engine speed and engine throttle position. In the SECU the engine torque map is used to position the engine throttles to match the drivers’ torque demand.

Are there any regulations that govern how you may control engine torque?

Yes; this is covered by Articles 5.5 and 5.6 of the technical regulations. The main points are:

Except for some specific exceptions, the engine torque must be controlled by the driver. These exceptions include: downshifts, pit lane speed limiter, anti-stall function and the end of straight limiter strategy. Note that this list is not exhaustive.
The driver may only control the torque by means of a single accelerator pedal.
At zero per cent pedal (off throttle), the torque demand must be less than or equal to zero; at one hundred per cent pedal (full throttle), the torque demand must match or exceed the maximum torque output of the engine in its current state (Article 5.5.3).
There are limits on the shape of the torque demand as a function of pedal position and engine speed (to prevent engine characteristics that could be driver aids).
Respecting these restrictions, the torque demand is shaped against throttle position and engine speed to deliver the desired response for the driver and car.

Can maps change from race to race?

Yes. Driver pedal maps can change as a function of the circuit characteristics. For example, drivers might want more precision during initial pedal application at Monaco. Similarly, some drivers insist on a wet weather pedal map.

The engine torque maps are also adjusted to take account of the engine’s power output according to the ambient conditions. The engines will all produce more torque on a cold day at Silverstone than at Interlagos (low pressure) or Malaysia (high specific humidity). This ensures that the drivers feel the same engine response at part load, regardless of weather.

Torque maps may also change as a consequence of changes to exhausts or air inlet (if teams introduce a new exhaust design or new air box).

This week’s new technical directive from the FIA requires us to submit reference map from one of the first four races of 2012, from which we can only vary ± 2%.

What was the issue with maximum torque in Hockenheim?

The FIA questioned the magnitude of difference between the maps from Silverstone and Hockenheim, where the maximum engine torque in the mid-range (10000-14000 RPM) was lower.

Why would would you want to generate less torque in the mid revs range?

The trade-offs concern driveability (the response of the engine to the driver requested torque), acceleration (less torque = less acceleration, except if grip limited) and fuel consumption. In general, reducing the torque is achieved by igniting the fuel later in the cycle by means of the ignition map. This may improve driveability smoothing out the torque curve which may help the driver manage his tyres. This is not in any way a forbidden driver aid or an attempt to mimic the behaviour of a forbidden system (eg closed loop traction control)

Reducing the maximum torque curve increases the amount of exhaust gas produced at lower torque levels very, very slightly, but does not change the exhaust gas flow at full throttle. Furthermore the scope to use the engine to generate exhaust gas is extremely limited by the specific mapping restrictions introduced for the 2012 season also by the performance trade-offs mentioned above

After two sessions today, has this made any difference?

Not significantly, but the workload for the trackside engineers has increased to ensure we maintain the same level of performance from the engine.

- Their rivals will be watching closely to see if this last line turns out to be accurate.

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34 Comments
  1. nino says:

    Vettel said that having these features banned by the FIA, is not affecting the general feel of the car…
    Probably it affects its performance Seb!
    Let’s see how it goes tomorrow….

  2. Wade Parmino says:

    This is an excellent explanation!

    I would love to see more of these types of explanations regarding other technical areas and devices in Formula 1. :D

  3. AndrewJ says:

    I’m not an RBR/Vettle/Renault apologist by any stretch of the imagination (Go Alonso!!), but this explanation from Renault does seem pretty reasonable. There are different maps for different drivers at different tracks in different weather conditions.

    Clearly RBR didn’t reap a huge benefit in Germany – otherwise they would have qalified and finished higher.

    So what is all the fuss about?

    If you’re not exploring and exploiting the limits of the regulations then you’re not going to be remotely competative and you shouldn’t be in F1.

    1. Dan says:

      That’s Abit to black and white, last week Qualifying was in the wet, which always mix’s the order up Abit and Alonso was unbelievable last week in keeping Vettel behind him.

    2. james h says:

      whos to say that with out these maps RBR would not of made Q3 and would of finished out of the points.

  4. Sebee says:

    See, justification and explanation due to embarrassment but not by RBR. Done by the engine manufacturer who’s product and brand is linked directly to cars.

    1. JackFlash says:

      Engine and ECU technical, operations, logistic data, and setting matters are Renault Motorsports responsibility to the RBR team, and all the other Renault V8 donk customers along the pitlane.

      It is Renault’s area of engine expertise, and for RBR to have made a technical statement ‘out of school’ to the Media, upon Renault’s technical turf, would have been most impertinent.

      This was the most proper avenuse for case/issue explanation – ie. from Renault Motorsport. RBR have chassis technical authority, not the engine.

      JackFlash.

  5. veeru says:

    cool changes to the site.

    well done James and team

    1. Craig in SG says:

      Can I just say, James, now that the main article is the full width of the screen it is quite difficult to read on a mobile device, as it cannot be zoomed in without stretching off screen (and my eyes are not getting any younger)

  6. Nitin Mathew says:

    Thanks for sharing this james

  7. Rich C says:

    Its all much ado about nothing.

  8. Aussie Tony says:

    James, was curious as to how rival teams get their hands on enough data to mount a protest. In this example, other teams protesting Red Bull’s torque mapping. Presumably that sort of data is fairly tightly held, apart from having to disclose to the powers that be such as the FIA. It is obviously different to a new piece of bodywork which the teams can photograph and scrutonise etc
    Cheers

    1. Andrew Carter says:

      Usually by sound analysis, but in this case it was the FIA that protested anyway.

  9. CH says:

    I’m sure all your readers here can deduce the biggest difference in SV and MW’s driving style.

    MW tends to be more gradual and gentle with his accelerator while SV prefers to stomp on it.

    Hence during the ages of Blown Diffuser, he trumped over MW. Since its banning in 2012, MW has been consistently faster than SV until RBR and Renault cheated with this contraption.

    1. xcellent says:

      CH you are a legend……you hit the nail on the head!!!

    2. Andrew Carter says:

      Not cheated. As the stewards themselves said, there wasnt anything in the rules stopping them from doing what they were doing. Now thats changed and RB have gone back to earelier maps that dont contravine the new rule.

  10. monktonnik says:

    “Reducing the maximum torque curve increases the amount of exhaust gas produced at lower torque levels very, very slightly, but does not change the exhaust gas flow at full throttle.”

    Sounds a bit like off throttle blowing to me.

    1. Martin says:

      To me, it sounds like you haven’t understood the article. To be off throttle, the driver’s torque demand is zero. Under the 2012 rules the engine torque demand is also zero unless certain factors apply such as downshifting.

      In this case, the Renault engine is delaying the ignition timing to smooth the power delivery. The fuel air mixture takes time to fully combust. The hot, high pressure gas does work on the piston forcing it down and the gas loses temperature. As F1 engines are not allowed to run variable valve timing, but delaying the ignition the combustion pressure acts over few degrees of crankshaft rotation prior to the exhaust valve opening. Therefore the exhaust gase temperature is slightly greater and greater pressure and it takes up more space.

      From mid 2010, what Red Bull and Renaultsport were doing was when the driver had zero torque demand at the throttle pedal, the throttles were still wide open, allowing the engine to pump air through exhausst. No fuel was added, so there was no torque demand. So this is cold blowing

      Mercedes Benz with McLaren started hot blowing well before Red Bull did. Here fuel is added even though there is no torque demand from the driver. Because fuel is being ignited there is a greater volume of air created. If you delay the ignition long enough to the point where the exhaust valves are already open then you basically get no torque delivered by the engine, but a lot of hot air produced by the engine. To prevent pre-ignition you could carefully control the throttle position so that the initial air flow is restricted, effectively reducing the compression ratio.

      In regards to the sound, Craig Scarborough (I saw this on Autosport) makes the point that Red Bull and Ferrari are now running Helmholtz resonators in their exhaust systems to boost overall performance across the rev range. Not attending the races, I’m not well placed to comment, but this is much more likely than the comments on this site about Red Bull running cold blowing systems.

      Regards,

      Martin

      1. monktonnik says:

        I’m not missing the point; I was reading between the lines.

        “Reducing the maximum torque curve increases the amount of exhaust gas produced at lower torque levels very, very slightly, but does not change the exhaust gas flow at full throttle.”

        If the amount of gas is increased at half throttle and this is channelled to the diffuser this sounds a bit like off throttle blowing to me; albeit a watered down version.

        I don’t know for a fact, but based on what what I have learnt from karting and track days, you tend to balance the throttle through corners. If this equated to holding the throttle half open you would get a small aerodynamic advantage through some corners.

        Again, it sounds a bit like off throttle blowing in application and I can see why the FIA have sought to clarify this.

  11. JC says:

    I don’t see why is not free for everybody … Enough controls already on engines.

    1. Martin says:

      I think it is the FIA going over the top on trying stamp out off-throtle exhaust blowing where the throttle, ignition and fuel delivery don’t go to zero.

      I believe the change was about driveability, possibly prompted by the wet qualifying in Silverstone.

  12. Steven Pritchard says:

    Okay… So if there is no benefit, why do it? My BSometer is on critical!

    1. Martin says:

      To improve driveability. Possibly prompted by the wet Silverstone, or a general aim to improve tyre life by reducing wheelspin. I strongly believe it is not aerodynamic related and that Rob White is correct in what he says.

  13. Really cool that the Renault engineers are making it so clear for us fans, even though it is to kinda justify their stand on the issue after the FIA banned their “QUESTIONABLE” torque map.

  14. Jonathan Silvester says:

    We’ll never know how far they could have developed the torque map to improve the car’s performance, it was clearly early days and the FIA have stamped on it before they could claim it was essential to the safe running of the engine, as they claimed with hot blowing last year.

    1. JackFlash says:

      Renault was Cold Blowing.
      Others like Ferrari were hot blowing.

    2. Andrew Carter says:

      Red Bull never ran hot blowing for reliability reasons, they’d just developed cold blowing further than anyone else.

  15. AlexD says:

    James, something is very wrong with how your website,it looks like some errors or changes happening with the blog. I check on several screen and I get errors…

    1. James Allen says:

      It’s fine, just refresh or empty cache. We did an update but it works fine

      1. Magnus says:

        Haninge problems on IPad too.

  16. One lunger says:

    PLEASE bring back the REAL F1, this ain’t it!

  17. John says:

    at last! The idea that traction control is no longer allowed has made me laugh for a long time. Finally we hear that, whilst controlling the traction at the wheels has been banned, it has simply been transferred to the ECU. Renault and RB have simply taken this to a new level.
    Rather than simply making sure that the driver’s input no longer overrides the ability of the tyres to convert power into speed RB have been working with their engine provider to vary the ability of the engine to convert petrol into power.

    Renault have been acknowledged as having the best ability to deliver power smoothly for many years. All they have done now is to combine that with the ability to maintain exhaust flow volumes.

    The most effective way to police this type of manipulation is to reduce the amount of fuel a car can use over a race distance.

    1. Martin says:

      I think you have a fundamental misunderstanding in how traction control worked previously in F1 in the early 2000s. Unlike a road car where TC and stability control can apply the brakes, in F1 the wheel rotation speed data for all four wheels was fed back to the ECU to allow the engine to reduce the torque. This was a closed loop control system with negative feedback. It was all done by the ECU, not at the wheels.

      The McLaren Electronics Systems ECU do not allow this feedback loop. Now if a Red Bull driver pushes the throttle to 75% travel and only gets 70% of the maximum torque, this makes no allowance for tyre condition, car speed etc. The driver will always get 70% of the maximum torque. If 71% of max torque is the point that wheelspin occurs in a second gear corner with fresh tyres, if the driver keeps using 75% throttle at this corner then eventually he will get wheelspin.

      Red Bull and Renault has done nothing to stop their drivers using 90% throttle in these corners and getting say 88% of maximum engine torque. The closed loop feedback control system involves the driver feeling the loss of grip and varying the throttle position to a known lower level. The ECU maps are constant and not part of the control system. The ECU acts as a (non-linear) scalar in the control system. The non-linear bit is irrelevant in this context (few things are truly linear).

      To state that Red Bull and Renault have taken something to a new level ignores the fact that we know nothing about what the other teams have been dong since the start of the season. What raised Jo Bauer’s concerns was the change. It could be that in this area, Red Bull and Renault are playing catch up to other teams.

      Getting back to driveability. Given the choice, F1 engine suppliers are going to prefer to vary ignition timing over throttle opening percentage to adjust the torque delivery. This is due to the reduced impact this has on the other cylinders. On the inlet side, varying the throttles will cause accoustic reflections through the air box and the relatively short inlet length means this is a bigger influence than the exhausts, which can be longer before the four pipes merge into one.

      With constant throttle openings you could reduce fuel delivery, but running lean creates its own temperature issues. I don’t know if there is quite the same precise control available with fuel delivery either to give the driveabilty desired, but yes controlling fuel useage would be a control in racing situations. Harder to police in qualifying.

  18. I find it amazing just how much of a beating that tyres can actually take during the amount of laps they endure. People often underestimate the progress in tyre technology for traction purposes.

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