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Thunf

Engine specialist...

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Thunf
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Hello!

I've read something on the net, but a veeery long time ago, why BMW usually are able to push more out of their engines than their competitors like Merc and so on... and still getting it long-term reliable.

I read something about a very highly educated aluminium expert that knows how to make the metal more lightweight but still durable. He has been working for BMW for a pretty long time... making very lightweight pistons. Certainly there are more people that are experts on aluminium, but I'm looking for the pioneer on it. Can anyone who knows something about it confirm it? I would also like to see a link to a page about the subject too.

Thanks!

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GIR
Geschrieben

BMW's expertise comes from a very long time of experience. Most of their performance addidtion comes from VANOS. While others need to use chargers, which destroy the engine in the long run, BMW can do even better with VANOS.

There are alot of systems like these in BMW's which account for performance boost but their superior engineers take credit for most of it.

thepolarfoxqx
Geschrieben

BMW's engines are well tuned, they employ a suite of advanced steps to increase performance. It is expensive, but not as hard on the engine. The VANOS, variable intake systems, advanced computers, and top notch tuning is what gives them great output.

LateNightCable
Geschrieben

True, and Mercedes for example, though their engines are very solid, they rely mostly on superchargers and large displacement for great power - the cheap and easy way.

Thunf
Geschrieben

ok, it explains at least. Yes, I know the VANOS... an amazing thing it really is! I said in my first post that BMW won't be using Valvetronic in their next M5, instead a third generation VANOS (and F1 like valves!).

Anyway, I might have confused me with Richard Hall, he played an important role on the aluminium constructions of, or near, the uprights of the E39.

Concerning the Valvetiming... I'm pretty sure other manufacturers are 'waiting'/developing the new 48 volt systems... allowing electromagnetic Valves. Then timing will be adjusted without the need of VANOS, or other variable valve timing systems... correct me if I'm wrong. I heard from one guy that the 48 volt system will save cables in the cars, sending different voltages in the same cable, he works for servicing on VW Group... but I also heard elsewhere that the 48 Volt system will allow electromagnetic valves ---> computer controlled valvetiming.

True, and Mercedes for example, though their engines are very solid, they rely mostly on superchargers and large displacement for great power - the cheap and easy way.

I'm not sure it's easy just because they use superchargers. Large displacement is another thing. Using 3 valves instead of 4 chosen by Mercedes needs larger displacement but have advantages too. Mercedes supercharger is turned on the same way as an airconditioner.. electromagnetic. I don't think supercharging and turbo technology is standing still just because it's considered an easy way. Today diesel eninges most uses turbo... it's not comparable to gasoline engines but still 'forcefeeding' technology won't stand still.

Sorry, but English is not my native language!!

Thunf
Geschrieben

-deleted message!-

GIR
Geschrieben

On a Diesel engine a turbo, charger or supercooler is a good thing. It doesn't have the side effects (turbo lag) that come with a Gasoline engine. Because of the nature of Diesel engines they alreayd have a very high compression ratio, this is why manufacturers couldn't use any form of forcefeeding on Diesel engines. But now they figured that trick out we're seeing more and more better Diesel engines. It's the whole world upside down.

With the use of newer tech Diesel engine's are moving towards a point where they will out perform their Gasoline counterparts. With the use of new carbon filters the emission of Diesel engines are lower then Gasoline engines.

The biggest problem of a Diesel engine is that it still lacks highend torque which limits its topspeed. But when it comes to low and mid range they will put down more torque then their Gasoline counterparts.

I've just seen a presentation on the new Fiat multijet Diesel engine. It's basicly a 4 cylinder V16 and it's very very small. With the use of multijet technology Fiat is able to make the engine perform even better with a noise reduction of 50% and considerable weight and size redutcion. VW has already announced they will use this tech in their next generation cars. My company is working on a Diesel pump for trucks which is based on the same principal, except that the V1 of this system is already done and available.

I heard something about those electromagnetic valves a long time ago. The biggest problem they had were that the EM field was affected too much by engine fibration and the stress on the coils was too much. The cservo needed replacing after just a few 1000 miles. Very usefull for racing purposes but on the road it's not so usefull. If they can figure out something to make the servo's more reliable it will be the way of the future. Personaly I think we will see pneumatic valves before we move to EM valves.

I once heard something about MB developing a 5 valves/cylinder engine. What ever happend to that? According to MB that engine could get a very equal and efficient burn.

The 48 volt system has one big draw back. Either you need a complete new set of chips specialy made for this purpose or you have to give every blackbox it's own voltage regulator. Either way it makes the electronics in the car expensive.

Anywayz like you've noticed, today it more about making efficient engines by tuning them and not about who can make the biggest engine and drop it into a car that can carry it. BMW is still one of the companies that does this best. Heavy big bored engines are a thing of the past and MB really needs to come of this philosophy. I know MB really has some great tech in their storage department, they just need to brush off the dust and apply it to an engine that has been newly designed from the ground up.

tallwingedgoat
Geschrieben

There's quite a bit of engine innovations out there that can vastly improve existing powerplants.

Alfa Romeo has their Jet Thrust Stoichiometric engine, Saab is working on one with variable compression ratio. And I never understood why Ducati's desmodromic valve gearing isn't being looked at for cars.

It's not so much that BMW is so advanced, just that most engine makers don't bother to try.

LateNightCable
Geschrieben

All of the carmakers are in the business of giving a damn about advancement, but BMW gives a very big one apparently. In that sense, their focus is more advancement oriented. It's ironic though, that for the longest time, their straight-six produced 189 hp out of 2.5 liters, which was kind of sub-standard. Even more so with the old 1.8 liter four ( 138 hp ). When the six became a 2.8 liter, power jumped to 225 hp.

The desmodromic valve system which dates back to 1910, was used succesfully by Mercedes during 1954 in a racecar, then Ducati began using it in the mid-60s'. It is a good system, but at least in motorcycles it requires periodic adjustment, so perhaps that is why it's not more popular.

Ventil_beweg.gif

tallwingedgoat
Geschrieben

Thanks for the pic of the desmo, I think it's really cool. But don't you think it's at least as maintainable as the pneumatic valves which has all those pressurized nitrogen leak problems?

For camless designs I think electrohydraulic is probably more promising than solenoids.

LateNightCable
Geschrieben

I imagine any system with nitrogen leak problems, and a need for an engine powered compressor would be alot more complicated to maintain than a desmo set-up :D . It's one of those mysteries, if they can build production engines that wind up to 8,000 rpm, why can't they build a maintenance free desmodromic valve unit for a car?

The simplicity of the design is poetic.

thepolarfoxqx
Geschrieben

one of the big issues of the desmo is that getting specific valve velocities is more difficult than with a spring lifter setup. It is very good if you have a specific single power band, but you don't have the extra valve motion dynamics introduced by a spring to play with.

Plus the adjustment would be a royal pain.

Latenight, are you complaining about the BMW 1.8L engine?

The M44 was junk (that would be the 1.9L 138hp), but the M42, the 134hp 1.8L was a great engine. It wasn't impressively powerful, wasn't really very torquey either. It makes more hp/L than the current 3.0L/225hp setup. It had variable intake runners back in 1990. That was impressive. It revved up and had top end torque like an engine far larger, and provided impressive accleration to the lightweight stripped down 318s. It was a 16V design with such features as piston cooling oil jet, an oil condenser in the heads, two stage throttle body, variable intake, digital ignition, and pent roof combustion chambers.

It was an incredible engine for its day. The 2.8L engine only bumped horsepower up 4 to 193. It was the 3.0 that moved it to 225.

Pneumatically actuated valves were never meant to be. The system is just far to complex.

Solonoids would have issues reversing directions at exremely high speeds. You aren't going to be turning 10 grand with solonoids opening your valves. Electrohydraulic does offer promise, but still very complex with limited advantage over a cam design.

Variable compression ratio? Isn't that why we created forced aspiration. Drop your compression real low. When you need it higher, force feed the engine to compensate. Saab? They are just a sticker to put on GM cars nowadays. A subsidiary of Opel if you will.

LateNightCable
Geschrieben

Ah, true, true. I was thinking of the motor in the E36 318i ( how come they don't call it a 319i? ) Come to think of it, it did take a few steps before the six made 225.

thepolarfoxqx
Geschrieben

remember that when the M42 came out in E30, the six cylender was 2.5L, SOHC, and only 2V/Cyl. The M42 was super modern by comparison.

tallwingedgoat
Geschrieben

"Solonoids would have issues reversing directions at exremely high speeds. You aren't going to be turning 10 grand with solonoids opening your valves. Electrohydraulic does offer promise, but still very complex with limited advantage over a cam design."

The cam design is basically 18th century clock design. It's a wonder we've kept to it for so long. Electrohydraulic promises infinitly variable valve timing and lift controls by the onboard computer. Ultimatly, you could configure engine performance with software editing instead of getting under the hood.

"Variable compression ratio? Isn't that why we created forced aspiration. Drop your compression real low. When you need it higher, force feed the engine to compensate. Saab? They are just a sticker to put on GM cars nowadays. A subsidiary of Opel if you will."

Problem is before the charger gives you full boost you are getting lower compression ratio than NA engines. Saab's variable compression is computer controlled to deliver optimum compression ratio across the whole rev range. Plus you can get very high hp/L ratio without the usual lag issues. When it gets into production it will be revolutionary.

LateNightCable
Geschrieben

Cams have been around this long because they are mechanical, and don't require fluid or extra power to operate. If something is mechanical, and it works, it'll be around awhile.

thepolarfoxqx
Geschrieben

this is true

nothing is that wrong with the cam design that it needs that much changing. it works really well if you think about it. So much has gone into refining it, it should.

Thunf
Geschrieben

Think what a flexible engine it would be if some of these technologies would be put together controlled by computer... let's see:

'Variocam plus' of Porche...

'Vanos' of BMW...

'Valvetronic' of BMW... (not necessary because of the Variocam plus)

variable intakelength

'SVC' by saab

Kompressor or turbo by Merc or some (with Vanos???!)

'Direct fuel injection' or 'FSI' by Merc or Audi (and kompressor??) :lol:

As you see, perhaps a combination of all isn't possible but by some it would really be a flexible engine!!!

But still the best engines will be beaten by electric ones as soon as power will be available for them. I saw a video of the Focus FCV some time ago, very impressive when steam came out of it as with the buss! COOL! And i'm also very impressed by the GM electrical vehicle doing 60mph in 7 sec!

thepolarfoxqx
Geschrieben

it could be interesting. Kompressor is just a supercharger. Variocam plus and Dual VANOS are the same thing, except Dual VANOS is more efficient and further developed, nearly all cars with variable valve timing have variable intake length (even my '91 bimmer has it), direct injection and valvetronic would work well together, though maybe not with a supercharger. SVC is yet to be finished, so i'll wait till i see it working to comment.

tallwingedgoat
Geschrieben

Porsche Variocam Plus is actually more sophisticated than Double Vanos because it varies valve lift in addition to timing. BMW acquired variable valve lift when they introduced Valvetronics in the new 7-series.

Of course there's nothing "wrong" with cams, there's nothing wrong with the sail either. But we have something better down the road. We are fast approaching the limits of mechanical control. There's only so much variable control you can get with cams. Imagine infinatly variable timing, lift, valve velocity both ways. Imagine optimizing your engine for high end or low end performance at the touch of a button. Finally the car computer gets to do what it's meant to do.

thepolarfoxqx
Geschrieben

actually, Dual VANOS does vary valve lift. Valvetronic is a system that replaces having a throttle body with computer controlled large swings of lift and timing.

cams will reach thier limits, i just don't think that day will be tommorow.

GIR
Geschrieben

That's what I was hoping for when BMW said they were going to have F1 style valves in the new M5. All F1 cars have pneumatic valves which allow total control over engine characteristics.

Ofcourse if BMW does introduce pneumatic valves then they wil incite a revolution. Other manufacturers can't stay behind so they will also have to introduce a similair system and development will slip into highgear.

Currently there's still much to work on when it comes to pneumatic, hydralic or EM valves. All have big failures and are only suitable for racing purposes. On a road going car they don't make sense at all, just yet that is.

I don't see EM valves happening in the next 5 to 10 years. Engine vibration and heat disrupt the servos too much.

Pneumatic and hydralic have three drawbacks and those are.

1. Pressure, you need alot of pressure to move the valves

2. Leckage

3. Complexity

As the E39 M5 proves so well, a hydralic system needs oil and lots of it. The E39 M5 consumed vast amounts of oil for lubrication and to power Dual VANOS.

A pnuematic or hydralic systeem needs pressure to power the valves hence needs a pump and that pump needs to be driven by something, the engine, which accounts for loss. A huge labyrinth of pressure lines and electronic valves add to the complexity and thus add to the weight and size of the engine.

I don't see these systems happening anywhere in the near future, but if BMW can pull it off (BMW is one of few manufacturers who can) then it will be a revolution in engine design. Heck I'd buy an E60 M5 even though it's a ugly duck.

Thunf
Geschrieben

Yes that's true. Losses exists if things are variable, more or less. Vanos neads high oil pressure, that's why a friend of mine said he's BMW E39 523i took allot of oil when it was new... perfectly normal.

Anyway, then take the SVC! Almost the whole engine needs to lean at constantly different angles... but that's still good as long as the driver can press different buttons, for instance: "Economy" where compression is 14:1, "Normal" where compression is 10:1 and "performance" where it's 8:1 and the turbo may charge for real. Then losses will be few compared to when the engine lean have to change all the time the driver press full throttle.

About the Variocam plus... read about it here, some may have got it wrong I think...

http://leo.worldonline.es/jaumepor/angles/tecnica/varicamen.htm

thepolarfoxqx
Geschrieben

you have any idea what is neccesary to change compression ratio without modifying displacement.

not worth the trouble.

Thunf
Geschrieben
you have any idea what is neccesary to change compression ratio without modifying displacement.

not worth the trouble.

Hmm... It's for sure allot of trouble. If ever SVC will be introduced... In my opinion, as I said, it would be better if the driver can switch compression ration (CR) manually instead of a system changing CR automatically depending on the throttle. SVC was doing that, the hydraulics was said to sound pretty much as it had to literally move the engine with the throttle, not very efficient I think.. but manually it would be better. :-?:)

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