How will teams handle V6 imbalance?

[riff_raff]

When it comes to crankshaft dynamic responses and the effect on the valve train, with a race engine the biggest concerns are the effects on valve timing. If you have an overhead camshaft drive consisting of 4 gear meshes, driven from the front of the the crankshaft, and the front end of the crankshaft has a torsional oscillation of +/- 1deg, while each gear mesh in the cam drive also has a backlash of +/- 1 deg, this would result in a potential variation in cam timing of +/- 5deg, which is huge.

Then there is also the torsional deflection in the camshaft itself that must be considered. A long, slender camshaft driven from one end will have much greater torsional deflection at the far end than the end nearest the drive point. So this must also be taken into account. I believe it is common for race engine camshaft lobes to be ground with different timings along the camshaft length to compensate for this effect. I have also seen the long camshafts of V12 race engines use torsional vibration dampeners mounted at the end furthest from the drive point.

[Edis]

When it comes to crankshaft dynamic responses and the effect on the valve train, with a race engine the biggest concerns are the effects on valve timing. If you have an overhead camshaft drive consisting of 4 gear meshes, driven from the front of the the crankshaft, and the front end of the crankshaft has a torsional oscillation of +/- 1deg, while each gear mesh in the cam drive also has a backlash of +/- 1 deg, this would result in a potential variation in cam timing of +/- 5deg, which is huge.

Then there is also the torsional deflection in the camshaft itself that must be considered. A long, slender camshaft driven from one end will have much greater torsional deflection at the far end than the end nearest the drive point. So this must also be taken into account. I believe it is common for race engine camshaft lobes to be ground with different timings along the camshaft length to compensate for this effect. I have also seen the long camshafts of V12 race engines use torsional vibration dampeners mounted at the end furthest from the drive point.

Pictures published in RET of the Toyota RVX-09 revealed that it has one pendulum type damper per camshaft on the non driven side. So it's not limited to V12 engines.

[ChipAyten]

Does anybody thing having 5 valves (3 inlet) would alleviate some of the exhaust harmony concerns? With more air and fuel in the chamber a greater pressure will be forced into the exhaust manifold.

[Greg Locock]

I don't. 3 intake valves has not proved to be a recipe for success generally, and it is hard to see how they would offer such an overwhelming advantage that you would throw away the increase in VE from tuning the exhaust headers.

[jamsbong]

Sounds like a challenge!
Even comfort is not a concern, reliability, weight and performance is.
It will be interesting to see how these vibrations get dampened while keeping the weight down, especially the weights of moving parts.

It will be a fascinating FEA work.

[wuzak]

in production by design, not accident, there were road 6 throw 60 deg V6s eg UK and German Ford designs
(inherently heavy and long, but less vibratory, having only the (much smaller) secondary couple )
the 60 deg angle was crucial to give even firing intervals, for a refined road car (despite the disadvantage to related V4s)

6 throw cranks on a V6? Really?

Got any pictures?

[Tommy Cookers]

if you go to http://ep90.com/index.php?id=29



the Cologne V6 was similar but had very thin webs
it became the 2.9 'Cosworth'
not to be confused with the Cosworth GAA, a development of the Essex
IMO anyone still making a road 60deg V6 will be doing basically as Ford did about 3 million times in Europe over about 30 years
the Essex (enlarged) was produced in RSA until a few years ago

[autogyro]

We developed a performance version of the 2.9 Cosworth V6.
It was fitted to a Ford Capri.
This makes a very inexpensive supercar.
It is essential to upgrade the brakes.
It is also advisable to move the powerunit back in the chassis 6 inches to improve the weight distribution.
The bell housing tunnel has to be cut out and remade and a shorter prop fitted.
We developed new cams for the engine on our engine dyno and used a progammable fuel and ignition ECU.
I could hold this car in an accelerating drift from zero to 100mph.
It would often break the backend away on wet roads etc.
I wish I had managed to develop it further.

The company specialised in the ford v6 and Ferari v8.
There was a Eurocar engine developed on both the Essex and the Cologne and Ferrari challenge engines.
A common road engine we built was the stroked Essex which I believe was 4.1 liter, using non ford conrods.
Exported a number to Australia.

I think Tony Southgate used the Cosworth V6 in the Jaguar XJ220 but it is a long time ago so I am not sure now.
Ford did use twin turbocharged 2.9 Cossys in transit rally service vans for a while 500 plus bhp awesome.
We raced a number of Capris from super saloons down to budget saloon. All used one or another version of the V6.

One ambition I did not achieve was to fit twin turbos to a stroked Cossy v6 Capri and try for over 500 bhp.

[wuzak]

Couldn't see clearly on the link you showed.

But I found this

http://img51.imageshack.us/img51/1087/2 ... 151452.jpg

and this little pic
http://www.essexengines.com/images/Crankshafdt.gif

Would have thought that was unusual for a V6.

Also found the Buick V6.

http://image.hotrod.com/f/8935838/113_0 ... kshaft.jpg

[Tommy Cookers]

Would have thought that was unusual for a V6.

Also found the Buick V6.

V6s were unusual (almost non-existent) anyway
apart from Lancia with 10-12 deg Vs with one head that they made from about 1920-70 (mostly V4s)
there was only (ever?) the 1950s Lancia 60 deg V6 (6 throw) before the Essex and Cologne Fords
the 60deg V has no overlap between 6 crankpins spaced for equal firing, so needs thick webs to join the pins
Cologne bounced itself to the V6, going all-V with related 60deg V4s (chosen for fwd)

a 90deg V gives lots of overlap between 6 crankpins spaced for equal firing, so the engine is shorter and much lighter
(overlap helped by choosing large bore:stroke ratio)
one of Mr Buick's better moves
handy to make on the same line as V8s (even related slant-4s ?)

useful pictures

[wuzak]

Would have thought that was unusual for a V6.

Also found the Buick V6.

V6s were unusual (almost non-existent) anyway
apart from Lancia with 10-12 deg Vs with one head that they made from about 1920-70 (mostly V4s)
there was only (ever?) the 1950s Lancia 60 deg V6 (6 throw) before the Essex and Cologne Fords
the 60deg V has no overlap between 6 crankpins spaced for equal firing, so needs thick webs to join the pins
Cologne bounced itself to the V6, going all-V with related 60deg V4s (chosen for fwd)

a 90deg V gives lots of overlap between 6 crankpins spaced for equal firing, so the engine is shorter and much lighter
(overlap helped by choosing large bore:stroke ratio)
one of Mr Buick's better moves
handy to make on the same line as V8s (even related slant-4s ?)

useful pictures

Ferrari also had their 65° V6. The extra angle was to allow room for intake runners, etc.

[Tommy Cookers]

yes, in the 60s and 70s it seemed all good (and we thought the car makers had been lazy or stupid before in neglecting the V6)
now I know why not
(Rover had tried a V6 in the 50s, later a straight 5 before buying Buick's castoff alloy V8)

the Peugeot/Renault/Volvo project seemed to confirm (with Fiat/Ferrari) that the true (ie 3 throw) V6 was the best (at any angle)
but Buick (starting with desperate improvisation) took the world to a better place

given the relatively low rpm-related loads inherent in the 2014 rules, the engines could be even more compact (than the 3 throw V6) if they had traditional co-planar (ie fork-and-blade or master-and-slave) rods, as last seen in the Martin V8 (or Harley D)
but that would disadvantage the 'MGUH design ?
modern bearing materials seem to allow narrower rods, so the co-planar benefits are less than traditionally (eg winning WW2)

[autogyro]

http://www.evo.co.uk/features/features/ ... o_6r4.html

You forgot this car.
I was involved with developing auto and semi auto competition gearboxes for Leyland at the time.
Mostly based on the bevel epicyclic AP geartrain as fitted to the automatic mini, 1100,1300 and metro.
John Davenport was involved with our projects and I advised on this one.
It was a V6 developed from the Cosworth DFV.
We did build a car with a V6 Essex ford for transmission development but the projects did not go far because of the cut backs in the industry.
Could have been a mid engined V6 8 speed auto competition and performance road saloon.
That was in 1976-8 great days.
We trialed an hydrolic central diff for this car which was later tried for F1, it gave full traction limiting and was of course banned.
Managed a four and a half day crossing of the Sahara with an early range rover with one fitted though.
The Metro 6R4 did well on the Dakar.
Hot Rod world champion Barry Lee drove one rally 6R4 for Toleman I believe, he also tested some of our development cars.
I think I still have the record for a couple of short circuit laps with one of our hot rods using a trick gearbox.

[autogyro]

Sorry but having checked a few things, it all starts to come back to me now.
This might shed some light on where V6 development was at in the 70s and 80s.
You will see that the Metro 6R4 could hit 60mph in 3.2 seconds and 8.5 to 100, as good as anything today.
A road version with 400 plus bhp would easily take the top slot on top gear.
It handled brilliantly, just needed my central dif for road use, the rally version was direct and wore tyres fast.

Patrick Head at Williams was responsible for the V6 DFV based engine for the 6R4.
Tony Southgate picked up the design at the end of the Group B rally era and used the engine in the XJ220.
Tony offered me an XJ220 in the Jaguar pit at the 1989 Le Mans for £50,000, wish I had bought it now.
I was at LeMans to discus powertrains, the engine was already in the Walkinshaw Jaguars in its ultimate form.
It was way over 600 bhp but I have not seen any proven data.
Now that in a 6R4 would be awesome on the road.
It had won the year before. In 1989 the Mazda Rotary had finaly been sorted and pushed the first Jaguar down to third place I think. What a noise those Mazdas made.

The point to be made here is that all this was in the late 70s early 80s and was all done in house at British Leyland.
Just think how far ahead Britains car industry would be today if it had not been fkd up by the stupid government.

Anyway I think it proves that the V6 is a sensible choice for F1.

[wuzak]

but Buick (starting with desperate improvisation) took the world to a better place

Are you sure it is a better place?

Anyway, the Buick V6 was a 90° bank angle, so it needed the 6 crank throws to get even firing intervals. Not convinced on the balance front, as late model versions used a balance shaft are were still not the smoothest things around.

Also, to me the offset throw crankshaft seems to be at a disadvantage from strength and/or weight to the 3 throw shaft.

given the relatively low rpm-related loads inherent in the 2014 rules, the engines could be even more compact (than the 3 throw V6) if they had traditional co-planar (ie fork-and-blade or master-and-slave) rods, as last seen in the Martin V8 (or Harley D)

There is no advantage for the 2014 in making the engine more compact. The engine mounting face and gearbox mounting face have to be a set distance apart (300mm?).

The master and link rod arrangement (as was used in the 1931 version of the Rolls-Royce R) the short stroke would mean an unusual piston motion for one side.

Also, in the fork and blade system, the fork sections would be thin and have to use small bolts.

Martin V8, as in Aston Martin?

but that would disadvantage the 'MGUH design ?

I suppose the master and slave rod system would mess up the timing a little, but other than that I can't see how that would affect the turbo/MGUH.

modern bearing materials seem to allow narrower rods, so the co-planar benefits are less than traditionally (eg winning WW2)

Most WW2 era V engines used fork and blade rods, not master rod and link arrangements. Of course the Rolls-Royce Vulture, Exe and Pennine all used master and slave rods, but they were X-24s, with 4 cylinders hanging off each throw. All the radials, naturally used master and slave.

The Rolls-Royce Eagle XVI of the mid 1920s (proposed to the same requirement as the F, which would become the Kestrel) was also an X engine, but with 16 cylinders. This had each pair of banks connected to fork and blade rods with two such sets side by side on each crank throw, meaning that the lower cylinders were offset from the upper cylinders. A similar arrangement was found in the Allison X-4520 of the late 1920s.