BMW Patents Its Electric Turbocharger Technology. More Power, Less Lag.

[goat128]

patent drawings have to be of a specific format like you see there.

[JRV]

Originally Posted by rosskie

if its very detailed someone can come in and do the same style turbo but different motor or bigger shaft and get away with it.

This way BMW can just say that was our idea u cant use it

exactly...would be foolish to make it all nice for everyone to see and copy before they even make it

[swamp2]

Originally Posted by Jblack4083

exactly!

A +3 (or 4 or whatever) on the cheesy drawings. Patent drawings DO NOT have to be hand drawn nor of any specific format. Certainly the comments about the less detail and the broader the scope apply, but come on hand drawn, really, by BMW...

That being said this could very well be the goodbye to turbo lag.

[maceBR]

simple smart and useful. like all great ideas.. way to go

[captbilly]

The idea of an electric turbocharger goes back at least several decades. The Russians used an electric motor/alternator coupled to a standard turbocharger on an aircraft engine (diesel) back in the 80s. I don't believe that BMW has the patent on the idea of en electric turbo, just the specific setup using the various clutches. It may even be that the only reason for the clutches was to get around the Russian invention, or to allow BMW to give the impression that they had some important IP for electric turbos.

Ultimately the idea goes all the way back to the turbo compound aircraft engines used on post WW2 piston engine airliners. In these engines the turbo is actually used to convert some of the waste energy in the exhaust power back to the engine/propellor (and of course also to power the turbosupercharger). In the turbo compound engines they used gears to feed the power back to the engine rather than the motor generator used on the Russian and BMW systems. These gears were the Achilles heal of the turbo compound engine because it was very difficult to build gearing systems that could match the very high RPM of the turbo to the very low RPM of the big radial engines of the day. A single backfire could tear up the gears, but even barring such a failure the gears were constantly getting beaten by the huge power pulses of the slow turning engine. The Russian application was the first I have seen that used a motor generator to harness some of the waste energy (energy not used by the turbo itself). I am not sure why BMW needs all the clutches and other stuff but perhaps they found that they got somewhat better efficiency under the varying loads of a car vs. the much more constant load in an airplane that the Russian system was meant for.

[Needsdecaf]

Originally Posted by vase330

C-E-R-A-M-C composite clutches anyone? They already make ceramic brakes that last a lifetime for cars such as Vette and some exotics. I am not sure I am the only one getting an epiphany here. They can use these materials to make the clutches. The space shuttle gets considerably hotter and uses a lot of ceramic composites, I don't see any issue other than cost.

Carrera GT used a ceramic clutch. It was unbelievably tricky to engage properly, from all reports. That is the sticky wicket.

perhaps now that gearbox management is by computer and is more intelligent than any human it might work but....

[tuna_hp]

Yeah it seems to me that the clutches are key to why this is such a good electric turbo application. Btw, it's not just old airplane engines, but many auto component companies have been exploring electric turbos for a few years now. Some of them completely separate the turbine from the compressor so they are only connected by electrical wiring, some use an electric motor to help spin up a traditional turbocharger.

The specific benefits of this BMW design seem to be:

-disengaging the turbine during coasting, idling, and launch means the exhaust can spin the turbine to a higher RPM and leave more energy for possible further turbos in a sequential setup to also spin to a higher RPM because it doesn't have to waste energy spinning the compressor (which wouldn't even create boost at that low engine speed, nor would boost be desirable even if it could).

-disengaging the compressor (along with the turbine) during coast and idle means that the electric motor can pre-spool to very high RPM while using relatively little energy because it doesn't have to waste any energy spinning the turbine or compressor around.

-Compared to the purely electric turbo concepts, the BMW design only requires one motor/generator versus having a dedicated motor and a dedicated generator, and maintaining the mode where you have a direct mechanical link between the turbine and compressor should be more efficient than having to convert pneumatic energy>mechanical energy>electrical energy>mechanical energy>pneumatic energy.

Originally Posted by captbilly

The idea of an electric turbocharger goes back at least several decades. The Russians used an electric motor/alternator coupled to a standard turbocharger on an aircraft engine (diesel) back in the 80s. I don't believe that BMW has the patent on the idea of en electric turbo, just the specific setup using the various clutches. It may even be that the only reason for the clutches was to get around the Russian invention, or to allow BMW to give the impression that they had some important IP for electric turbos.

Ultimately the idea goes all the way back to the turbo compound aircraft engines used on post WW2 piston engine airliners. In these engines the turbo is actually used to convert some of the waste energy in the exhaust power back to the engine/propellor (and of course also to power the turbosupercharger). In the turbo compound engines they used gears to feed the power back to the engine rather than the motor generator used on the Russian and BMW systems. These gears were the Achilles heal of the turbo compound engine because it was very difficult to build gearing systems that could match the very high RPM of the turbo to the very low RPM of the big radial engines of the day. A single backfire could tear up the gears, but even barring such a failure the gears were constantly getting beaten by the huge power pulses of the slow turning engine. The Russian application was the first I have seen that used a motor generator to harness some of the waste energy (energy not used by the turbo itself). I am not sure why BMW needs all the clutches and other stuff but perhaps they found that they got somewhat better efficiency under the varying loads of a car vs. the much more constant load in an airplane that the Russian system was meant for.

[mweisdorfer]

There is only one reason for this and it is to put it in the m3. Eventually, you will see it used across the board in all turbo charged BMW's giving better gas mileage as a result.

[Singletrack]

Originally Posted by mweisdorfer

There is only one reason for this and it is to put it in the m3. Eventually, you will see it used across the board in all turbo charged BMW's giving better gas mileage as a result.

It's already in the M550d.

[ScheerSpeed]

pretty cool!

now this will get interesting with how the aftermarket decides to "tune" an electric turbo...

[andrey_gta]

I want to knwo how easy this will be to add the electric turbo to other engines, such as the n52

[BMRLVR]

Originally Posted by Singletrack

It's already in the M550d.

Sorry, but there is no electric turbo on the N57S, just 3 conventional turbos that are brought on-line at different points in the RPM range.

[nsphoto]

Originally Posted by Robin_NL

Tip:Just wait for the prices of second hand 458s to decrease. 9000rpm.

Brilliant hot tip, I concur.

As for the new turbo design, it seems so simple, how is it that someone hasn't applied this concept already years ago?

[bimmerjph]

I just read some where that Audi was developing this too.

[Boss330]

Just found this thread and it seems to confirm that something similar to what will be seen i F1 next year might be on the M3/M4:




Of particular interest is the MGU-H (Motor Generator Unit - Heat) that is attached to the turbo:

TURBOCHARGER
A turbocharger uses an exhaust driven turbine to drive a compressor to increase the density of the intake air consumed by the engine and so make more power for a given displacement.

The residual heat energy contained in the exhaust gases after expansion in the cylinders of the engine is converted to mechanical shaft power by the exhaust turbine. The mechanical power from the turbine is used to drive the compressor, and also the MGU-H (see below).

As the turbocharger speed must vary to match the requirement of the engine, there may be a delay in torque response, often known as turbo-lag. One of the great challenges of the new Power Unit is to reduce this to near zero to match the instant torque delivery of the current V8 engines.

MGU-H
The MGU-H is connected to the turbocharger. Acting as a generator, it absorbs power from the turbine shaft to recover heat energy from the exhaust gases. The electrical energy can be either directed to the MGU-K or to the battery for storage for later use. The MGU-H is also used to control the speed of the turbocharger to match the air requirement of the engine (eg to slow it down in place of a wastegate or to accelerate it to compensate for turbo-lag.)

This is a brilliant piece of engineering, possibly a game changer of power delivery characteristics on a turbocharged engine

Any rumours of a electric turbocharger on the next M3/M4 might be a similar device as shown here, to spool up the turbos, or slow it down instead of using a wastegate to dump excess exhaust.

Source: http://www.renaultsport.com/Nouvelle...Energy-F1.html

Here is MagnetiMarelli's version of a "electric/hybrid" turbo. TThey have chosen a slightly different solution with the generator/motor unit between the compressor and turbine units of the turbo. Seems like Mercedes is using a variant of this solution as well.





BTW, this is what next years F1 engine will sound like:

[RMB]

If BMW did something like this for the M3/M4 it would make it a really unique engine. I think this would be great and it would potentially represent the next leap forward with FI engines.

[RingMeister01]

Genius

[Boss330]

Originally Posted by Torgus

You Don't need a 90kw engine to spool a turbo up or a crank shaft.

You don't need a 90kW motor to spool up a turbo, that's correct.

However if you want to add the complexity and weight of a hybrid drivetrain to the engine (crank) you need sufficient battery capacity to make it work for more than a few seconds a time. The weight of the electric motor, and the necessary coupling/transmission to connect the electric motor to the crank, isn't that different if you have a 30kW or 90kW motor added.

And, if you choose to add a hybrid drivetrain then you want to make the most out of the weight penalty that follows from this.

For instance the McLaren P1 has a 130kW/177hp e-motor, the Porsche 918 a 94kW/128hp and the LaFerrari a 118kW/161hp e-motor. And even a Prius has a 49kW/67hp e-motor. Look at a Prius and you see that the hybrid drivetrain adds weight and complexity, even at that low power output... And with very little gain in performance...

Picture illustrating what's involved in the hybrid drivetrain, in addition to the combustion engine and transmission, on a Prius:



If you really want to add the weight and complexity of a hybrid drivetrain, you also want to add enough kW/hp from the e-motor to the drivetrain to make a noticeable difference in performance.

And, even a e-motor to spool up the turbo needs a separate high voltage battery system. For instance a modest 2kW output at 12V would need 167Amps... Studies from 2006 by Garret on the viability of a "e-turbo" showed that a single turbo was preferrable since that required a 2,1kW motor, while a twin turbo set up required two 1,4kW motors. The study also showed that under normal driving conditions there wasn't enough exhaust gas flow to sufficiently take advantage of the e-motor attached to the turbo as a generator. Implying that the batteries would need charging in addition to the charge available from the e-motor.

I personally find the e-turbo tech very fascinationg and hope to see that employed in road cars soon.

But, this is getting seriously off topic now. I suggest that the hybrid/turbo material/tech discussion is either closed now, or continues in a dedicated thread (like in one of the old threads that discussed hybrid turbo tech in depth).

[Boss330]

Originally Posted by Torgus

Link to that garret article? Sounds very interesting to read.

There is no reason they would use a 12v supply, they would want to crank the voltage up much much higher.

I'm confused about there not being enough exhaust flow? The reason you want to put an electric motor to spin up the shaft is exactly that. If you have a link to when this was discussed before can you post it? I've always been very interested in that tech specifically. I would think you would want to decouple the emotor feo. The turbine once it was up to speed otherwise it's a drain.

That's why I wrote that they would need an additional high voltage circuit

And one of the main points besides turbo spool up, is to harvest electrical energy from the otherwise wasted exhaust gases. This is what the MGU-H does on the current F1 engines. MGU-H means Motor Generator Unit -Heat (heat as in exhaust gases). The MGU-H serves a dual purpose. It works as a motor and spools the turbo when boost is needed quickly, and it serves as a wastegate by braking the turbine shaft, thereby harvesting electrical energy while operating as a generator. This works great on a engine that spends most of the time either on 0% throttle or 100% throttle. On a daily driver the throttle is much more often on part throttle and too little exhaust gas flows through the turbo for the MGU-H to be able to harvest energy from the exhaust gases...

I have uploaded the Garrett PDF file as an attachment.

Here is presentation from 2003 that I just found on the subject:

http://energy.gov/sites/prod/files/2...eer_shahed.pdf

An SAE article

https://www.sae.org/automag/features...1-113-9-86.pdf

[Boss330]

Originally Posted by saxonb

Audi's 2016 SQ7 will have an electric turbo.


Article about it on Autoblog: http://www.autoblog.com/2014/08/08/a...rging-feature/

Thanks, great find

[Bowser330]

Check out phantom electric superchargers. They are using electric motors to drive centrifugal compressors.

They have dyno proven results in several types of cars.

Unfortunately the systems are rather small however I wonder if two systems one for each turbo could work on the S55.

Compounding turbo technology could be an alternate to turbo upgrades, by pre-pressurizing the air charge the pressure ratios are multiplied and the stock turbos can produce higher than normal boost pressures more efficiently.

Thoughts?

[crashtestdummy81]

I thought this all initially sounded good but looking deeper the advantages seem to be unavailable from such a system under real world conditions.

Using electricity to drive the T/C at low engine speeds will help reduce lag but the electricity has to come from somewhere, unless you are driving with sufficient load after pulling away (a situation where a normal waste gate would be opening) there can be no electric generation without slowing the turbo, the charge used for spooling the turbo will need to be replenished from the vehicles electrical system.
Conversely If you are driving under high loads where you have plenty of excess exhaust to drive the generator this charge needs to be stored somewhere, should the battery reach a state of full charge you have no facility to stop the turbo over spooling unless the waste gate is retained.
Based on this it would seem that the battery sizing and initial charge state would need to be tailored to the actual driving conditions the vehicle is about to experience to be fully effective.
Other manufacturers have had success with combined turbo+supercharging which removes the need for the (heavy) batteries these systems would require. The supercharger is clutched in only at low rpm before the turbo spools up or under heavy throttle for increased performance, so as to minimize power taken from the engine.


Ultimately though, I feel that the anti lag system employed in the S55 (even though I'm not really sure quite how this works) is sufficient to render the concept of electric turbos redundant.


The electric supercharging concept mentioned in the previous post may be suitable as a performance upgrade but you would have to consider the size/weight of any batteries required to run this for any sustained length of time. A mechanical supercharger would be a more efficient option should you consider using the vehicles existing (or upgraded) electrical system as you cut out the losses associated with turning mechanical energy to electrical energy, electrical resistance and then turning it back to mechanical energy again.
An alternative idea would be to use the electrical supercharger like a rechargeable NOS system, having a much smaller battery being trickle charged from the vehicle when not in use but giving a short term bump in power at the push of a button, only when "needed", before waiting for the battery to recharge.