Cosworthpressrelease Attachment 230207

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THE Australian Grand Prix will be the first since 1967 in

which the Northampton, UK-based race engine manufacturer

Cosworth will have no involvement.

Twelve months ago, it all looked so different. The new 2.4-

litre Cosworth CA V8 engine was running reliably at 20,000

rpm. It generated sufficient power for F1 observers to predict

that the Williams F1 team, which would be racing with it, could

return this famous alliance to the top step of the podium.The FIA’s new Formula One engine technical regulations for

2006 called for a 2.4-litre 90 degree V8 layout. The minimum

weight of the engine was set at 95 kilogrammes; cylinder

bore size was limited to 98 mm. The minimum height for the

crankshaft centreline above the reference plane on the

bottom of the chassis was set at 58 mm. A minimum centre

of gravity height for the engine was also set, at 165 mm

above the reference plane.

The regulations also placed restrictions on the materials that

could be used in the manufacture of components.

For its new-generation F1 engine Cosworth set ambitious

performance targets that included running at a crankshaft

speed of 20,000 rpm. Key factors in achieving this were the

understanding of the torsional vibration characteristics of a

high speed V8 engine and their effect on valve train control,

further reductions in frictional losses and piston design.

Torsional vibration analysis was done using a combination

of computer modelling and the dynamometer testing of a V8

version of the 3-litre TJ V10 (“TJ V8”) engine that was built in

the autumn of 2004.

“We learned a lot from that engine,” says principal engineer

James Allen. “We had a target from the beginning of running

to 20,000 rpm, which we did with that engine, and so we

were able to explore the torsional vibration behaviour across

the whole speed range. It’s such a big speed range for an F1engine that you encounter all sorts of problems and go

through all sorts of different resonances.

“With the TJ V8, and with the simulation work we did, we

identified a big torsional vibration mode between the two

camshafts on the cylinder head. The exhaust cam and the inlet

cam went into resonance, out of phase, and the effect was

much worse with the V8 because the excitation was different.

“We put a lot of work and time into increasing the stiffness

between the camshafts, which we did by reducing the

number of gears between them so that they drove eachother, and by introducing extra bearings at the front to stiffen

up the support for the gears.

“We had used compliant elements in the V10 valvetrain but

for the V8 we had to increase their stiffness and then introduce

some known flexibility to avoid increased backlash. At first on

the V8 version of the V10 we struggled to control that resonant

peak, because of the V10 gear drive. But having modelled it,

we were able to understand it. We addressed it by developing

torsional vibration dampers mounted on the rear of the

camshafts for the CA V8 that we were able to test on the TJ V8.

“The TJ V8 also helped us with performance tuning. With the

V8-V10 we were able do torsional vibration and performance

38 www.racetechmag.com March 07

ENGINES COSWORTH CA V8

20,000 RPMAND OUT!This season the Formula One circus will be without one of its leading players, Cosworth. Alan Lis meets four

of the company’s top engineers to discuss the CA V8 engine, considered to be its most innovative powerplant

since the heady days of the DFV


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ENGINES

ABOVE What might have been:

Cosworth’s CA V8 had the potential to

recreate the company’s glory days.

Financial reality – Frank Williams

describes F1’s new regulations as “a

charter for bankruptcy” – dictates that

the project is left without a customer

LEFT Cosworth manufactures its own

pistons (this is from the V10 engine)

and has made major leaps forward in

this area in recent years

development work from when we first ran it, in December

2004, right up until the middle of 2005, in parallel with the

design of the CA, which began in January 2005.”

Managing frictional losses was fundamental to the design

of an engine capable of running at 20,000 rpm; the CA was

the culmination of work Cosworth has done in this area over

the past 10 years.

“In the late 1990s we were investigating a V12,” says Allen,

“and we made a slightly smaller capacity version of the

existing CK V10, which we ran at 20,000 rpm, to see what

power we could get. The frictional losses were huge on that

engine. All the work we have done over the years, preventing

those losses, led us to the point where it was sensible to run

that fast, and make use of it on the CA.”

“The progress Cosworth has made in terms of reducing losses

has been significant,” says Simon Corbyn, head of F1 race

engineering. “It is the cumulative effect of numerous detaildesign changes including reduced oil flow, bearing

development, finger follower valve actuation and low friction

Managing frictional losses

was fundamental to the

design of an engine capable

of running at 20,000 rpm

“

”


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coating technology. All of those things have added up together

to give us the results we have now.

“The motored friction of a 2006 CA at 19,500 was the same

as a 1996 JD at 16,500 if you normalise it for the reduced

number of cylinders, and think that has been achieved in 10

years, that is pretty impressive.”

Piston technology is another area in which Cosworth has

made significant advances. “The piston has been the limiting

factor in how hard we can run the engine in terms of speed,”

says principal engineer John Vaughan. “We spent a lot of time

on the TJ improving our understanding of the pistons to

make them reliable.”

PISTON PERFECTION

“Pistons are a Cosworth internal success story,” says Corbyn.

“We manufacture our own, so there is a close relationship

between design and manufacture. You’ve got to do the

analysis work to understand it and make sure the detail

design is right, then control the manufacturing and build

processes very well. The quality and accuracy requirements

are so demanding now that a single scratch in a critical

region means you can’t use that part.

“Pistons are matched to individual cylinders for a specific

engine, so there is a whole process of scheduling your pistonthrough the machine shop, getting low friction coatings

applied and so forth, so it all becomes pretty involved.

Because we have complete control of the piston, they were

basically a non-issue on the CA. We were also helped by the

fact that the bore size on the TJ was relatively small for a high-

revving V10 engine at the end of 2005. It was 95 mm bore

and we went to 98 mm with the CA, which turned out to be

the limit of the technical regulations so the mean piston speed

came down as well. All of those factors added up.”

For Cosworth the CA represented a significant investment.

“Our design philosophy was to try and make it as right as

we could first time, using our resources very wisely because

Cosworth was bankrolling the project,” says Vaughan. “That

meant we did a lot of analysis and a lot of simulation work.

The TJ V8 was the way we could check those models were

behaving correctly and then we could use them in design.

When the engine first ran we could have confidence that it

would be right.”

At one point during the summer of 2005 it wasn’t certain

that the CA project was going to go ahead, because Cosworth

hadn’t got a customer. But in July 2005 the Williams F1 team

signed a contract to race with Cosworth engines in 2006.

Despite the uncertainty, design work on the CA had

continued and a major decision, arrived at through the

modelling process, was reached soon after the deal between

the two companies was concluded.

“The Williams gearbox design had already started, assumingthat the clutch was on the engine,” says Corbyn. “We had to

have a pretty tough conversation with them to weigh up the



merits of them redesigning their gearbox to accommodate a

clutch, or us having to redesign the engine concept to put the

clutch on the engine. Based on the evidence from the

simulation work, and the running on the TJ V8 engine, it was a

pretty compelling technical argument for putting the clutch on

the gearbox. Williams, to their credit, just got on with it.”

The first dyno run by a CA V8 was in the middle of October

2005. Although the 2.4-litre CA V8 was to all intents a brand

new engine, a number of components and systems were

carried over from the 3-litre TJ V10. They included the oil tank,

the oil pressure and scavenge pumps, the alternator drive and

the airsprings for the pneumatic valve system.

“Where we did not think we were going to get a real

contribution towards our target, the designs were not

changed,” says Allen. “Our target was maximum power,

maximum engine speed, and there was the minimum weight

rule that came in for 2007. That removed some of the

pressure to redesign everything to make it all a little bit lighter

again than it was

before.”

The biggest difference

between the CA and TJ

was the cylinder head

design. “When we were

doing the upgrade toincrease the speed on the V10 we found that the structure of

the cylinder head was not very good for valve control at the

speed we had targeted,” says Vaughan. “The TJ cylinder head

was extremely lightweight, having been designed when there

was no minimum engine weight limit.

“For running at 20,000 rpm the camshafts were not very

well supported. You need to try and get the loads from the

cam bearings down into the area where the cylinder head is

bolted down into the crankcase. The construction of the CA

We knew that our performance targets, and what we had

achieved, were significantly better than all our competitors“

”

March 07 www.racetechmag.com 41

ENGINES

LEFT Magic figure: the interim TJ V8

reaches 20,000 rpm on the dyno.

Some people dismissed it as a PR

stunt, but in fact the CA ran at that

level even at its first test in the car

BELOW The existing V10 (this is the

TJ head) was converted to a V8

interim unit that was used to gain

valuable lessons through torsional

vibration analysis



cylinder head was completely different in that regard. There

was more scope for cam bearing support because the cg

height rule meant that there could be more material and

weight higher up on the engine.”

The CA ran in a car for the first time at Barcelona in

November 2005. In its first dyno test the engine had run

comfortably at 20,000 rpm, and would do so at its first car

test as well.

“Keke Rosberg was there, because he had gone to watch

Nico,” says Corbyn. “He asked what we were running the

engine to, and I said, ‘We’ll run to 20,000 once we’vecompleted basic systems checks.” His eyes were like saucers

and he said, ‘I thought that was an aspirational target?’ I said,

‘No, no, we are going to do it later on this afternoon,’ and

that came as a surprise to quite a lot of people.

“We ran two chassis at the first test, which was quite an

achievement given how late the deal had happened with

Williams. We didn’t have very long to get the car installation

sorted out. Williams worked overtime to get the gearbox and

the car sorted out for that first test.

“From talking to some of our suppliers, who obviously deal with

multiple engine manufacturers, we knew that our performancetargets and what we had achieved were significantly better than

all our competitors, so it was an eye-opener.”

Early testing gave light to an unforeseen problem that was

attributed to the air valve system. “Our AVS is not very complex

in that nominal spring pressure is not a function of engine

speed and the first version of the CA had too narrow a cam to

support the spring loads under all running conditions with the

new cam designs,” says Corbyn. “That meant that while the

engine could happily run at 20,000 rpm, it couldn’t

idle in the garage! The problem was fixed fairly quickly

and didn’t turn out to be a major issue in the long-

term, but in the initial test the drivers were asked to

turn the engine off when they came into the pit lane.”

“We changed the compound valve angle,” says Allen. “At

first we had the lobe and the valves coming out at an angle,

which changes the contact load between the two. We had to

make the cam lobes wider, and redesign the follower

geometry to cope with that.”For the first race of the 2006 season, at Bahrain, Series 2 CAs

incorporating the camshaft changes and rated at 740 bhp were

in the back of the Williams FW28s of Rosberg and Mark Webber.

Webber finished a competitive run in sixth place; Rosberg

staged a spectacular recovery from a first corner spin to finish

seventh and set the fastest lap of the race on his F1 debut.

Rosberg and Webber qualified third and fourth respectively

for the second round, in Malaysia, but neither car made it to

the finish. Webber was sidelined by a hydraulic failure, while

Rosberg suffered what would be Williams’s only engine-related

retirement of the year when a big end bearing failed.“In Bahrain the maximum duty available was 20,000 rpm

with optimum ignition advance,” says Corbyn. “That was used

42 www.racetechmag.com March 07


Pistons are a Cosworth success story“ ”

LEFT Cosworth works closely

with the foundry, using Finite

Element Analysis casting

simulation to control what can

be the longest lead time and

highest tooling costs for an

engine. This shows a snapshot

from the casting simulation of

a cylinder head. The part hasnot yet been optimised by

analysis and so shows several

problem areas




BELOW Webber’s Williams-

Cosworth qualified on the front

row at Monaco and looked set fora podium finish before retiring

with an exhaust problem

for the key laps in qualifying, and key

periods of the race such as the start. After

the problem in Malaysia we reduced the

maximum duty to 19,500 for qualifying

for the next two races. With the bearing

issue resolved, we were back up to

20,000 for the European Grand Prix.”

Webber placed sixth at San Marino and

Series 4, the next CA development step,

was introduced for round five at the

Nurburgring. It raised peak power to

747 bhp and included lightweight

components, which brought the CA

down to the minimum weight limit

whilst maintaining the defined centre of

gravity height.

“Before 2006 there was nothing in the

regulations about centre of gravity

height, so everyone was trying to get it

as low as possible” says Vaughan. “On

the TJ we were working very closely with

Jaguar and at that time the trend was to

make the bottom of the engine heavy. If

you made the sump a lightweight piece

the team would only add ballast there

anyway, so pretty much everything

below the crankshaft centreline was

made heavy. For a while the TJs that were

used in the Jaguars had brass sumps.

“The 2006 rules specified a minimum

cg height and a minimum mass for the

engine. The minimum weight rule was to

stop people making engines from super

light and super expensive exotic

materials. The cg height rule was to stop

people designing superlight engines and

loading ballast on the bottom of them.

“Unfortunately, the two numbers

specified didn’t really go together. When

we first designed the CA we could get it

to the minimum weight but the cg was

too low. We ended up making parts

above the cg artificially heavy – by doing

things like adding weight to the airbox –

and making parts below the cg

artificially lighter, by doing things like

making a heavily machined thin-walled

sump. That rather defeated the object of

rules that were intended to make people

produce engines that were more robustand straightforward.”

In the Nurburgring race Webber

suffered another hydraulic failure, while

Rosberg again finished seventh. At

Monaco Webber qualified on the front

row of the grid and looked set for a

podium place before he was eliminated

by an exhaust problem.

We ended up making parts above the cg artificially

heavy and parts below the cg artificially lighter“

”


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The final Series 6 CA development step, offering

peak power of over 750 bhp, was introduced for

round 11, the French Grand Prix at Magny-Cours.

By this time the engines were running to over

2000 kilometres in dynamometer endurance tests.

Shortly before the next round, the German

Grand Prix at Hockenheim, it was confirmed that

the Williams team would be using Toyota engines

in 2007. A potential deal for Cosworth to supply

CAs to Spyker was torpedoed by the team’s

announcement on the eve of the Chinese Grand

Prix – in which Webber was eighth – that it would

use Ferrari engines instead.

Thus the 2006 season’s closing race in Brazil

would be Cosworth’s last Formula One race for the foreseeable future. With a new regulation

coming into force for 2007 that limited maximum

Keke Rosberg asked what

we were running the engine

to and I said, ‘20,000 rpm’.

His eyes were like saucers

“

”

HOW can it be that a company that built what was widely perceived as one

of the most competitive and reliable of 2006 F1 engines can now no longer

be involved?

“There are only a limited number of customers you can potentially sell to in

Formula One,” says Simon Corbyn, Cosworth’s head of F1 race engineering,

“and while our customers were very impressed with our product, it’s an

inescapable fact that using Cosworth engines costs teams money.

“We are limited in terms of business-to-business relationships because we

don’t have a big corporate partner. There are other factors which may trump

the technical advantage of running the Cosworth engine.”Bruce Wood, chief engineer, adds, “If you’re running an F1 team and a

manufacturer is going to give you a lot of money, that means you can do maybe

another 50 days of wind tunnel testing. That will almost certainly make your car

go faster than the extra engine power, as well as bring the business-to-business

relationships. It’s hard to make a case for not going with a manufacturer.”

Corbyn is also at pains to assert that the CA remained competitive throughout

2006. “It’s a fallacy that Cosworth were overtaken during the season,” he says.

“Yes, we were absolutely at capacity and working very hard, but we started the

season with a competitive advantage and the engine was competitive at the

end of the season. In today’s Formula One the engine is not the most significant

factor to overall car performance.”

“For everybody at Cosworth it has been a brutal reality check,” says Wood.

“So many times over the years I have heard people say if we do the best job,

the customers will come to us. I think last year we actually did the best job and

nobody wants us. That was a bitter pill to swallow.”

WHERE DID IT ALL GO WRONG?

BELOW On sheer performance, Cosworth’s CA V8 deserves to be on the starting grid

at Melbourne this month. Instead, the company’s UK division has shed 200 jobs since

the start of last season. It retains its core engineering skills, if not full capacity



ENGINES

engine speed to 19,000 rpm, Cosworth

announced that it was aiming to set a

benchmark in Brazil: it would become

the only engine manufacturer to run its

engines to 20,000 rpm for a full grand

prix distance.

Unfortunately, this plan to go out of

Formula One on a high note came to

naught. The Williams drivers collided

with each other on the opening lap of

the race and both were eliminated.

“For the last few races of the season

we had been running at 20,000 rpm for

about a third of the race and in dyno

tests we were able to run at that speed

for 500 kilometres. So we were prettyconfident that we could have completed

a race distance,” says Corbyn.

For the record, in dynamometer

testing the best of the CAs developed

755 bhp at 19,200 rpm at barometric

pressure of 1013 millibars and a

temperature of 16 degrees C. The best

of the 2005 3-litre TJ V10s developed

915 bhp. Scaling the CA up to 10

cylinders, its peak power output would

equate to 940 bhp.

CFD STUDY OF FUEL INJECTION AND VAPOUR DISTRIBUTION IN AN F1 ENGINE

ABOVE Cosworth has done advanced work

developing and customising injection andspray modelling with 3D moving meshes

BELOW A bearing pressure plot. Cosworth

uses CFD to study the likes of steady state

port flow, fuel atomisation, airbox and exhaust

simulation using 1D-3D modelling, oil motionin a tank and crankshaft oil aeration

Documents

Cosworthpressrelease Attachment 230207