F1 Tech in ‘Race Engine Technology’ Magazine

This months ‘Race Engine Technology’ magazine has some interesting stuff for F1 Tech followers. There’s an interview with Mario Ilien, who explains the work he did with Mercedes-Ilmor including; Hydraulic KERS, a rotary valved V10 (+20k RPM & 78Kg) and of course Berylium for Pistons & Liners.
In the Report from the F1 British GP, the Editor interviews Adrian Newey, Also Costa, Sam Michael and James Allison. Covering several topics; the effect of engine powerdrivabilityconsumption, as well as gearbox design influence on aero, with Newey commenting the Pull Rod was a carry over from 09 & not a requisite for his RB6 design. While Ferrari confirmed their enginegearbox assembly is inclined at over 3-degrees, the first time I’ve seen a reliable quote confirming this fact. It was added that Sauber take this set up for their C29, while Toro Rosso have their own gearbox so have a horizontal drivetrain.
Lastly is a small section on how Sauber pioneered current gearbox design with a longitudinal gearbox, with the gears ahead of the final drive and contained within an aluminum case. It surprised me that Harvey Postlethwaite was involved in this, is there anything that man didn’t do in F1?

Not generally available in the shops and not cheap, but well worth a one-off purchase or subscription.

http://www.highpowermedia.com/mall/productpage.cfm/RET/2049/348121

RACE ENGINE TECHNOLOGY 048 AUGUST 2010

Intro: THE EDITOR
Racing powertrain technology is on the verge of a revolution; Ian Bamsey says this issue gives some hints as to what to look for

Upfront: MARIO ILLIEN ON FUTURE TECHNOLOGY
Ian Bamsey talks to Mario Illien about his pioneering work in Formula One during the V10 era and the future of race technology

Grid: IN THE NEWS
Peugeot’s con rod dramas; HPD’s new LM P2 V6 turbo; Le Mans’ Hybrid u-turn; John Medlen’s new role at DSR and much more

Dossier: PORSCHE 911 GT3 R HYBRID POWERTRAIN TECHNOLOGY
Ian Bamsey investigates how flywheel-based storage of recovered kinetic energy has been pioneered in professional racing

Race Report: BRITISH GRAND PRIX
Despite the ongoing engine freeze, Ian Bamsey discovers some significant powertrain developments at the British Grand Prix

Focus: CAMSHAFTS
Wayne Ward discusses the options available for the design, materials and manufacturing methods for race camshafts

Insight: RACE ENGINE INSTALLATION
Le Mans-winning designer Peter Elleray on the relationship between engine and chassis design, highlighting where their needs conflict

Focus: THE GEARBOX
John Coxon explains key points in designing and building a motorsports transmission – from the gear teeth to choice of differential

Race Report: LE MANS PROTOTYPES
Ian Bamsey gives a rundown of the various engine strategies deployed by this year’s Le Mans Prototype competitors

PS: SAUBER C12 TRANSMISSION
How in 1993 Sauber’s first Formula One car prompted a major shift in transmission technology

To view a sample article from this issue please click here

Price £12.50

Germany Tech Review now on Automoto365.com

My Technical review from Hockenheim is now on Automoto365.com.  With the update on McLarens Blown diffuser, Mercedes and Williams exciting ‘open-fronted’ exhaust blown diffusers, as well as updates from Virgin and Toro Rosso.

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Red Bull Map-Q: The secret to the teams Q3 pace

As explained in my post on ‘EBD’s’ – Exhaust blown diffusers (http://scarbsf1.wordpress.com/2010/06/25/exhaust-driven-diffusers/), teams blowing their diffusers rely on the throttle being open to keep airflow passing to the diffuser. Without this airflow, the diffuser loses downforce and the driver suffers a loss of grip or balance just as he enters the corner. 

While careful design and how the exhaust is placed in relation to the diffuser, can alleviate some of the problems, any benefit from blowing the aerodynamics will be reduced when the throttle’s closed and no exhaust gasses are flowing. 

It’s been reported that Red Bull are following a practice that was used on turbo cars (i.e. the old F1 turbos and WRC cars) to keep the turbo spooled up. By means of retarding the ignition when the driver is on the overrun as he slows for a corner. If Red Bull can keep the flow out of the exhaust pipe relatively constant, even when the throttle is closed going into a turn, then the diffuser will see a more consistent air flow and maintain downforce. Relieving it of the onoff throttle sensitivity so often a criticism of EBD systems. In effect an antilag system is trying to do the same as the Red Bull EBD mapping, maintaining a constant exhaust gas pressure, on or off the throttle. 

Ignition normally occurs within the cylinder, driving the engine

 

When an engine is running normally, accelerating with the throttle open, the ignition of the fuel and air takes place inside the cylinder above the piston. The expansion of the gasses drives the piston and turns the engine. 

After ignition, the exhaust valve opens and the cooler gasses rush down the exhaust pipe

 

During this process the gasses then escape into the exhaust pipe as the exhaust valves opens. As the burning has already occurred the gasses are some what cooler, the then temperature of the actual ignition. This means the exhaust gasses flow down the exhaust pipe with some speed and energy. 

On a closed throttle, little air or fuel are burnt reducing the exhaust gas flow

 

When a driver lifts off the throttle, the engine does induct much air, nor burn much fuel, as a result the engine slows and the exhaust flow also slows down. It is this problem that affects the diffuser, as it sees less exhaust flowing through it. 

With retarded ignition, the mixture burns in the exhaust creating a flow of gasses through the exhaust

 

What Red Bull do is retard the ignition and maintain some throttle and fuel to allow combustion to continue to take place. However the ignition of the air and fuel mixture now takes place later in the engines revolution, when the exhaust valve has already opened. Rather than driving the piston down, the explosion of the mixture goes into the exhaust, still expanding as it does so. This creates a rush of gas through the exhaust mimicking the effect of running with the throttle open. Thus the diffuser still sees a flow of gas and maintains downforce despite the engine slowing down. 

Retarding the ignition overheats the exhaust components (red)

 

Of course this gain doesn’t come for free, the heat of combustion now takes place in the exhaust port, so that the exhaust valve, cylinder head and exhaust pipe all suffer excessive heat. This will affect them, as they cannot withstand this sort of thermal load for long periods. Equally the process burns additional fuel, in the race this is a negative thing as fuel is limited and no refuelling is allowed.
This ignition retard mapping would be controlled via the SECU via the driver selecting a steering wheel control, using quite normal tuning parameters and not some clever workaround. Of course this is all quite legal. 

If the overheating issues can be contained, this would be a relatively simple mapping to introduce for another EBD team. As mentioned Renault Sport, Red Bulls engine supplier would have to know about this. Copying the concept, but not the actual SECU code would be quite easy.

Valencia: Technical review now Automoto365.com

 

My Technical review is now online at Automoto365.com.  With the latest updates across the grid.

http://bit.ly/aGG7yC
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Valencia: Technical Review now on Racecar-Engineering.com

My Technical review is now Racecar Engineering Magazines Website. With News on the Ferrari, Renault and Mercedes blown diffusers, Red Bulls and williams Vaned double diffusers, Everyones f-ducts and all the new bits on the cars including Ferrari, McLaren, Renault and Williams.

http://bit.ly/cy1Q3H
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http://www.racecar-engineering.com/articles/f1/475053/f1-2010-european-gp-technical-updates.html

My work also gets published along with other technical motorsport articles in each months Racecar Engineering Magazine…

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Exhaust Driven Diffusers

Red Bulls Exhaust exits low and blows through the diffuser

Not withstanding the 2009 downforce reduction rules, the diffuser continues to be the dominant factor in aero design. Making the most of creating low pressure under the rear of the cars bodywork is as important as ever. Last year we saw teams exploit rule loopholes to create additional underbody inlets feeding larger exit areas, known as the double diffuser. This year teams have further exploited these rules for ever larger inlets and outlets. However it has again fallen to Red Bulls Adrian Newey to look at the history book and re-invent a concept that has since fallen out of favour. Last year he did this with the pull rod rear suspension and this year it has been the exhaust driven diffuser. By mounting the exhaust outlets in line with the floor, they blow through the diffuser driving greater airflow and hence creating more downforce. It seems for the team’s midseason upgrades, many will follow Red Bulls lead.

A diffuser is a simple device; a diverging duct creates low pressure under the car, creating negative lift, i.e. downforce. The FIA has acted several times since the mid eighties to cap the potential of the diffuser by reducing its length, height, ride height and position relative to the rear axle. Moving through the diffuser is the key to it producing downforce, or Mass flow as the aerodynamicists call it. This can be achieved with the size of the diffuser itself, effectively capped by the rules, but teams still are split on how large an exit they want to create within the current bodywork rules (McLarenRenault large exit, Red BullFerrari smaller exit). Onset airflow is another factor controlled by the front wing, bargeboards and the floor itself, but this is somewhat capped by what can be achieved with the limited devices the rules allow for. Then there is the flow over the top of the diffuser, this has been perhaps the biggest area of development in recent years. By ending the diffuser with a gurney flap, the airflow over the top of the diffuser can actually aid airflow underneath the diffuser. This is the reason sidepods have become slimmerundercut and the diffuser appears more exposed amongst the coke bottle bodywork. Effectively the harder the air flows over the diffuser, the more powerful the gurney can be in puling airflow from inside the diffuser; this makes the diffuser act as though the exit is larger and makes more downforce. As long as a car needs bulky sidepods (even bulkier with this years fuel tanks) then the potential power of the airflow over the diffuser is limited. However we have a secondary source of powerful airflow at the rear of the car and that’s the exhaust pipes. Using the flow from the exhaust pipes can actually drive airflow through the diffuser, either by blowing inside the diffuser or over the top and driving the gurney flap. This isn’t a new solution, in fact Renault exploited this as early as 1983, when diffusers first appears in place of the banned full-length ground effect tunnels. Renault split the pipes exiting the turbocharger into three and directed them exactly at the point where the flat floor kicks up the form the diffuser. Soon most teams followed this format and for twenty or so years teams experimented with different exhaust outlet positions within the diffuser. As F1 switched from turbocharged engines to normally aspirated, the flow out of the exhausts was no longer ‘smoothed’ by the action of the turbo, the flow became much more abruptly on or off. along with the increasing dominance of the downforce created by the diffuser, this made the amount of downforce produced vary depending on throttle position, i.e. more downforce at full throttle where the flow was aided by the engine, then less downforce as the driver lifted off reducing the through flow. To negate the effect teams moved the exhaust outlets from the diffusers kick line to a less sensitive position, normally further up the diffuser roof. Eventually teams sought to avoid any sensitivity and move the exhausts clear of the diffuser and blew them over the top of the exit. Until Ferrari shifted their exhausts to exit periscope style in 1998. Most teams followed this approach aside from a few teams, which wanted to keep the blown effect, notably this was Both McLaren and Minardi. Eventually both teams had to divert from blown diffusers in order to package the much shorter exhaust pipe lengths demanded by the engine suppliers. It was Adrian Newey at McLaren that raced the last heavily blown diffuser, the MP4-16 exited its pipes low down in the middle of the diffuser. In 2002 the MP4-17 went to periscope exits due the demands of the Mercedes engine. At the cars 2002 launch he told me “Requests from the engine supplier, from Ilmor, was different exhaust system requirements which meant we could no longer continue with putting the exhausts exits out through the floor so we had to go for top exits”. I asked if this was an engine related requirement not aero, Newey said “yes”. I further prompted him if this was for shorter pipe lengths? He replied “I’d rather not go into details; we couldn’t accommodate what was wanted”. Underlining his commitment to the blown diffuser philosophy, I asked he’d tried try top exits on the old car (mp4-16)? Newey said “No never”.

McLarens MP-15 blew its exhausts into the diffuser

But Newey reverted to a blown diffuser for the highly experimental MP4-18 in 2003. The exhausts exited relatively high in the side channels to blow into the taller middle tunnel. However the routing of the exhaust past the all new carbon fibre (double clutch) gearbox lead to problems and along with other technical issues the car never raced. Replaced by the MP4-17D and MP4-19 both with the by now conventional periscope exhausts.

McLarens still born MP4-18 blew its exhausts towards the middle of the diffuser

This year Newey designed the RB6 to have a blown diffuser, although it was first tested with the conventional RB5 exhausts, it was only at the last test the team unveiled the secret exhaust development. Even replacing the old exhausts with look-a-like stickers to fool the unwary. This development was posted here back in early march, as was the opening into the diffuser. Strangely many fans back then denied the systems appearance and the fact it blew through the diffuser.
The RB5 that preceded this year’s car, already had high placed rear wishbones, and this allowed the subsequent car to run exhausts mounted low down and exit well below the wishbone, avoiding any overheating issues of the carbon fibre components. Teams have run exhausts in very close proximity to the wishbones now for many years, the differing strategies teams employ reduce the thermal load on the carbon fibre wishbones. Either gold foil film, extra carbon fibre heat shield or these are often coated with ceramic finishes to reflect heat. This latter finish being made obvious by the matt silver finish tot he parts. Sauber have run these on their top rear wishbone for many years. The heat shield even having a small air inlet to feed cooling air in-between the heat shield and wishbone beneath. Teething troubles may be expected as the teams start to run the new exhaust positions, but the heat protection will be a solution relatively easy to overcome. 

the inlets for the diffuser (yellow) are visible behind the exhaust outlets

The inlets for the exhaust flow are visible within the diffuser (yellow)

Contrary to the popular belief the low exhaust position is not related to the Red Bulls Pull rod suspension, in some respects having the exhaust in close proximity to the pull rodrocker linkage is undesirable. But the exhaust positioning is probably more sensitive to wishbone position, such that teams aiming for low wishbones may have problems packaging the exhaust under the suspension. McLaren and Virgin have notably low wishbones.
In the RB6′s case Newey made an opening in the diffuser to allow the diffuser to be blown both under and over by the exhaust. This probably helps the airflow going up the outside shoulder of the upper diffuser deck, which probably has little energy and struggles to keep attached. Other teams this weekend may be expected to run a diffuser blown over the top, which perhaps offers less potential then a through blown diffuser, but at least will be legal next year when double diffuser are by banned by new rules preventing openings in the diffuser.
Another misconception of the low exhaust is the effect on tyre temperature. It’s possible the exhaust does affect the inner shoulder of the rear tyres, but this may well be an effect teams want to discourage. Any tyre heating will certainly be secondary benefit of the system and the sole reason for going with low exhausts. Its interesting to note Red Bull have run a fence on the floor between the exhaust and rear tyre. This probably helps keep unwanted heat from the tyres. But in Canada, where tyre temperatures were, this fence was removed. It could be that the tyre heating effect could be a tuneable parameter, by varying the heat shielding around the coke bottle area.

So far we have seen Ferrari, Renault and Mercedes have followed Red Bulls ‘back to the future’ exhaustdiffuser solution. McLaren and Williams are expected to follow suit for the enxt race At Silverstone.

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