Audi BMW

The BMW N55B30 represents the current workable technical edge of gasoline engine performance and economy. It is a state-of-the-art powerplant available in the 535i GT and soon the 535i from BMW. It is possible, that before long the N55B30 will supplant the N54B30 in BMW’s entire lineup.

To gain a better understanding of the technical advances contained in this engine, it is necessary to develop a simple example of a gasoline Otto cycle engine. This will be used to help explain the benefits of the technology contained in the N55B30.

Consider, for example, a simple stationary engine. It is designed to run at peak torque. The engine must start and then quickly hit its optimum RPM. The air/fuel mixture is restricted for starting (for which the amount of fuel to air is increased). This will ‘light’ the engine off and, once started, the restriction or ‘choke’ can be removed. From here, the throttle is moved to provide operation at the optimum RPM. There isn’t much more to it than that. In addition, the valve timing is optimized for the single RPM requirements of the engine.

Now, depending on the method with which the air/fuel mixture is introduced to the engine, the performance and emissions characteristics of the engine will vary significantly or slightly. It is most apt to vary significantly if a carburetor is used to supply the air/fuel mixture. That is due to the inherent variability of the mixture arriving in the combustion chamber. The carburetor does not optimize each and every air/fuel pulse, it simply hopes for a happy medium.

Carburetors work on the Bernoulli principle. They draw air past a venturi and the vacuum created draws fuel from a hollow needle (jet) creating an air/fuel mix. The amount of air/fuel mixture allowed to flow to the engine is controlled by a throttle plate. The carburetor, inherently, does not provide optimum fuel economy and emissions control.

A mechanical fuel injector is better than a carburetor in that the fuel will be metered relatively precisely.

Fuel injection utilizes a nozzle that can be opened and closed to inject pressurized fuel into the air stream. However, some early mechanical fuel injection, as used in the old sprinters and Indy cars, was often described as a controlled leak. Electronic fuel injection, however, delivers more precision over the air/fuel mixture.

In the history of gasoline engines, electronically controlled port fuel injection was a key enabler of emissions compliant performance engines.

Now, an engine optimized for a single RPM has it uses, as a lawn mower for example, but it is useless for an automobile. (Even hybrids that use an IC motor for an electrical generator allow for some variation of engine RPM).

The engine has to perform perfectly over a range of RPMs sufficient to meet any potential driving condition. One approach to this is to vary the intake and exhaust valve openings in relation to the combustion process so that they are optimized over a range of engine RPMs. BMW accomplishes this with its double-VANOS technology.

VANOS changes the relative position of the cam lobe in relation to the combustion cycle based on engine load and RPM. It can smooth out the power band of an engine, making an engine feel less ‘peaky’, for example.

Variable lift of the intake valves can alter the use of a throttle in the engine. When a throttle is used to vary the volume of the intake charge allowed into the cylinder, the engine has to work against the throttle during partial throttle opening. This results in lost work, known as pumping losses. Imagine the work required to pull a sheet of paper away from the nozzle of a vacuum cleaner. That, in a very simplistic way, is what pumping losses are.

Varying the lift of the intake valve can change the volume of charge allowed into the combustion chamber, this can require less work than the tugging against a closed throttle. Of course that depends on the amount of work needed to provide the variable lift mechanism. The variable lift mechanism has to return power at a rate better than the potential pumping losses to be effective. What variable valve lift buys is increased fuel economy.

BMW uses Valvetronic to provide variable lift to the intake valves of an engine. It utilizes an intermediary between the rocker arm and cam lobe whose shape is designed to change the total lift of the valve depending on its position in relation to the rocker arm and cam lobe. This allows for a variable lift profile, within a specific range, unlike the original VTEC which is a simpler (yet effectively clever) solution.

So with double-VANOS, Valvetronic and port fuel injection we have the foundation technology for the N52B30 engine familiar to NA BMW owners as the x28i models.

But let’s take that basic suite of engine technology, enhance the performance and miniaturization of the Valvetronic components and add direct injection and forced induction like the N54B30 and you have a recipe for real success.

Direct injection works well in an engine that allows significant variations in valve timing and forced induction. Since it must deliver fuel directly into the combustion chamber, it subsequently utilizes higher fuel pressures than port injection to overcome the pressure of the compressed air charge in the cylinder. It is a key enabler in the new round of emissions compliance and fuel economy requirements that would otherwise inhibit engine performance.

One more piece of technology merits a brief discussion and that is the Twin Scroll turbocharger used in place of the twin turbochargers used on the N54B30. By using a single turbocharger, that maintains exhaust pulse separation ahead of the turbine, an exhaust pulse reaches the turbine every 120 degrees of crank rotation rather than every 240 degrees of rotation for the dual turbocharger setup on the N54B30.

Coupled with Valvetronic and VANOS, direct injection and the twin scroll turbocharger, BMW provides the same performance across a wider RPM range for less fuel consumption in the N55B30 than the preceding N54B30. Quite an accomplishment.

Exclusive Interview with the Head of BMWNA Product Planning and Strategy/BMW Motorsport Manager, Martin Birkmann – A Look into the Future World of ///M Cars, Racing, and Current Engine Tech.

At the recent 2010 NAIAS, we got a chance to speak with Martin Birkmann who is the Head of Product Planning and Strategy with BMW NA, as well as BMW Motorsport Manager in the U.S. If you haven’t already, we advise you get some coffee brewing or pop-corn popping – what follows is extremely interesting information about current and future BMW products.

With BMW’s new engines, the revamped N54 and now the N55, what have you upgraded on the N54?

Martin Birkmann: With the N54 we’ve basically changed the mapping of the engine, pressure of the engine, given it a more sporty, more torquey, and peak oriented performance curve.

Martin Birkmann, left, Bobby Rahal, right, during the unveiling of the BMW M3 GT2 ALMS

What are the differences between the N54 and N55?

Martin Birkmann: At first glance we’ve changed something in the architecture, we made the engine more compact, but in terms of costumer benefit the biggest change is the application of VALVETRONIC. With variable valve lift we eliminate the throttle and so we’ve made the engine again more efficient than the N54. The N55 is maintaining the N54’s base performance level, but gives you a lot of enhancement on the efficiency side

Will we see the N55 engine across the range?

Martin Birkmann: We started announcing the N55 for the 5 series GT so you can expect to find it in the regular 5 series sedan, one series, and we’ll roll it out for more and more applications.

With the new 5 series, what kind of changes can we expect to see on the new M5?

Martin Birkmann: I think it’s been widely speculated and confirmed that we’ve somewhat seen the dawn of the end of the NA engine. M is no exception, we’ve launched our first turbo M engines and I think that will be the biggest difference if you look at the tech spec sheet – that we will go with turbo charging for the M5. There is speculation that I don’t want to comment about; we will clearly see a change in the transmission strategy, we are still examining the need for a second transmission variant. We’ll know more about that as we go forward, as you know, every one should know that BMW NA in persona is a big proponent of manual transmissions and three pedal vehicle operation, but it’s not a trend that you see in the market gaining a lot of momentum right now. Our customers want more semi-automatic transmissions, so that’s a must, and everything else is a can. We’ll see as we approach the launch of the car.

What clear future do you see for BMW and racing?

Martin Birkmann: ‘Racing’ and ‘clear future’ sounds almost oxymoronic, I think for the US market there’s a clear preference on the consumer side for production style racing, for tin top racing if you will. We’ve followed that through with the M3 program now going into the second season, and for the production run of the M3 – that’s a program that we hope to maintain with its car-presence. For us racing is about competition, it’s about aspiration, it’s about excitement and thrill. The grid that we find in the ALMS series just serves that perfectly. We have a great set of competitors that we respect and that we want to be respected by. We all do our utmost to earn their respect on the racetrack and that’s how I see racing for the US market. Formula 1 is a thing of the past now; we have to acknowledge that. We’ll see if that frees up ideas for other kinds of racing, but the statement I want to make for the US is production car racing.

With BMW doing so well in their return to ALMS, do you see any possibility of BMW entering LMP1 or LMP2 class racing?

Martin Birkmann: For us to go racing it needs to be relevant for our enthusiast fans, followers, supporters, and the best way to achieve that is with a road going version of the car. So we’ve started racing with the road car, it is not a silhouette racer, it is really a car that started its life off as an M3. With a prototype you lose some of that if you compare a prototype of type of brand x, y or z to each other; other than livery on the car it will be very difficult to associate a brand with them. That’s something that we addressed, we have had some great brand attributes such as the kidney grill on our last prototype car, but generally it is difficult because you follow the form of the prototype a lot more to the aerodynamic laws than you do with production cars. Again, production is the first priority of today.

What are the capabilities of DCT on M and non-M cars in terms of performance enhancement?

Martin Birkmann: You have the same basic 7 speed slush-box that is actuated with the double-clutch, you have a difference in cooling performance, rev-ability and then of course you also have an extra feature which is the drive logic in the M cars that allows you to change the characteristic of the gear changes.

With all of BMW’s experience in Formula 1, what lessons have been learned for the road cars and for technology to come forward?

Martin Birkmann: In the technology transfer between racing and road, I think the majority goes today from road to track. If you think of electronics, if you think of traction systems, brake systems, suspension systems, these are all things that we have a much broader data base on in our road cars, that our racing program can benefit from. The fact that we have, I don’t know how many million units in operation with stability control systems, and the ability to evolve those – allows us to make our race cars more efficient on the track and use the tires more efficiently. I think the technology transfer primarily goes from road to track, especially when you think about electronics. Lightweight componentry is something we experiment with on the racecars more. We have less cost inhibitions on the racing cars, that is something that we can possibly translate to the production cars going forward.

How does twin-scroll turbo technology compare to variable-vane turbo technology in terms of turbo lag and performance?

Martin Birkmann:  Both of them can improve the response of the turbo engine. It depends on what your underlying engine architecture is. The benefit of the line up that we’re offering in the United States is that we’re offering a relatively large displacement so you clearly can say that the turbo is not used as a crutch to make a lame engine go, it’s a fantastic engine that you make go faster. That helps with the performance and the turbo lag. The engine electronics, the control of the VANOS in harmony with the VALVETRONIC (which improves the breathing), the twin-scroll and the variable-vane all contribute to reducing the lag. I don’t think you can rule out one of these technologies against another, they all contribute to make it better. Right now we use variable vanes only for small displacement engines in combination with twin scroll and we will apply it as we see necessary. I can tell you that the N55, in terms of linearity and response, yet increases the benchmark in terms of what a turbo engine can feel like.

What limits engine RPM on turbo motors and will it be possible to produce a high revving turbo for M applications?

Martin Birkmann: You don’t get the same benefit in terms of performance from a turbo as you get from a NA engine. The redline of our current turbo M engines is 7000rpm. Our first commercial M car was the M3, it had a redline of 7200 rpm, so I think that answers your question. We’re already high revving but the question is, what is the benefit that you see going up and up and up. One of the clear paths for the next generation M3 is to improve driveability and pickup out of every rev range and every gear especially in street legal speeds. The US market is the biggest M5 market, that’s not something that the V-10 has shown in the past.

Would it be possible to develop a diesel engine with M personality and drive characteristics?

Martin Birkmann: I think it’s a challenge. We started to be a bit more liberal with M engine configurations as of late. I think the field of high performance diesels is extremely intriguing. You will not get infinite levels of revs out of a diesel and you don’t need too, but I don’t see that this is something that can never happen. Right now we have a very different purchase motivation for our diesels cars than our gasoline cars. To me the bigger question is: is there a market there, is there a need there? We are looking into it.

Is it possible to develop higher revving diesel engines above 5000 rpm?

Martin Birkmann: Because it’s a self inducted engine you basically have a limit on how high you can rev them and that’s about 5000 rpm for all we know.

How low lag are the N54 and N55 turbo engines, and have BMW been able to successfully eliminate lag from their turbo engines?

You’ve driven a lot of BMW turbos, so that answer I give to you, but my answer is yes. We brag a lot and look a lot into middle seconds and response times and what not; you drive a conventional car, any motor, the response time from throttle input to arrival at the wheel is two tenths – so everything that you do to beat two tenths suffices to omit any kind of lag and we are way beyond that.

We would like to give our special thanks to BMW NA and Martin Birkmann for this enlightening interview.

BMWBLOG Editors, Josh Lewis and Shawn Molnar

The audio interview can be found below and in advance, we would like to apologize for the lower quality sound, the microphone “stalled” for a second.

BMW 3 Series Coupe facelifted test mules continue to be seen during testing sessions. The E92 and E93 life cycle impulse models will make their debut at the Geneva Motor Show in 2010 with U.S. sales commencing in April 2010.

The latest spy photos show us again that the major changes in this LCI are around the headlights. The upcoming models will feature a slightly different design with the headlights now embedded in the front apron and have a downward curvature at the outer edge, as is clearly visible in our image comparison below.

Furthermore, for the first time the prototypes seem to feature new and brighter Angel Eyes, as seen in the new 5 Series. These rings are now LED daytime running lights powered by its lighter color and are even more obvious than before.

Apart from that, we expect headlights LED flashers like the E90 facelift, and the now typical “eyebrow” at the top of the headlights, similar to the one in the 7 Series, Z4 roadster, X1 or the new 5.

At the rear-end, we expect, as with any new other models, a slight L-shape of the light rod which will give the facelift models of E92 and E93 an unmistakable night-time look. Looking at the spy photos, the kidneys are slightly flattened at the top and they held just 13 grilles from the usual 14th on the current model. As with all the new models and thanks to the EU safety pedestrian regulations, much larger exterior mirrors caught our attention.

Front and rear aprons and side skirts are also rumored to received slight changes. Even though not featured here, one of the prototypes spotted was carrying the Vermillion Red pain that was not previously offered for the E92 models.

Engine wise, several rumors have been floating on the internet, but so far none of them confirmed by BMW. It is still uncertain on whether the new N55 twin-scroller turbo will be used or just an upgraded version of the current twin-turbo N54.

The upcoming 5 Series includes the new four-cylinder diesel engine with 184 horsepower, but once again, we’re unclear if this engine will be used in the current 3 Series line-up.

With a world premiere in Geneva, the first official photos should hit the web sometimes in January.

[Source: e90post ]

The all-new F10 5 Series is all but upon us now and this marks a new turning point in the history of the 5 Series and a continued change in direction for the designs and technologies of BMW. The original 5 Series was unveiled decades ago, an impressive high performer, with the production models going on sale in 1972 as BMW’s first mid-size executive sedan thus making the 5 Series line-up 37 years old and the oldest moniker in BMW’s existing line-up.

So, as you can imagine, the F10 5 Series has 37 years of success as well as pressure to shoulder as the 5 enters its new stage of life and sixth iteration.

It goes without saying, the F10 is the most technically advanced 5 Series to date. BMW has packed full the new midsize sedan and delivers in spades with the performance in terms of the engine line-up that the U.S. market can expect with the F10 platform. The line-up in terms of naming will not change from the existing E60 550i, 535i and 528i but buyers can expect wonderful surprises under the carefully sculpted hood.

The existing 4.8L V8 from the E60 will be replaced by the current 750Li’s N63 4.4L twin-turbocharged V8 producing an impressive 400HP with 450 lb-ft. The new 550i is expected to return a 0 to 60 sprint of 5 seconds flat – very impressive considering that’s the same sprint time of an E39 M5! With the twin turbo technology, the N63 manages the difficult balancing act of handing over heavy-hitting performance figures while returning respectable fuel economy for even those of us with the heaviest of right feet.  However, the engine does without the Valvetronic system of the previous E60 4.8L V8 as a result of the turbochargers keeping the intake pressurized. Additionally, BMW is able to keep the overall turbocharged V8 package much more compact by placing the catalytic converters between the cylinder banks and thus keeping the turbo plumbing to a minimum.

As impressive as the top-of-the-line V8, BMW will be providing the public with two staggered, high revving inline-6 cylinder engines. The new N55 engine will carry the 535i moniker from a twin-turbocharged 3.0L inline-6 to a single twin-scroll turbocharged 6 cylinder though, incredibly, without sacrificing power or efficiency. In fact, according to engineers, the single turbo N55 manages to produce serious power as low in the rev range as 1,200 RPMs thereby trumping the twin-turbo N54 lump by 200 RPMs. In speaking with BMW directly, we were told that the N55 will only have a slight weight penalty of perhaps 4 or 5 pounds over the N54 – so there isn’t much lost in that second turbo.

However, where the N55 really shines is that, aside from producing 300HP like the N54, it manages to shed one of the turbochargers and pick up the throttleless Valvetronic system thereby increasing throttle response while reducing emissions and improving fuel economy. The N54 is an award winning engine and rightfully so, but, there will no doubt be resistance to the loss of the N54 to the N55. Once behind the wheel, it is expected that most drivers will not be able to notice the difference. BMWBlog expects the 3.0L twin-scroll turbocharged 6 sometime in the early to mid Spring also around when it will hit with the 5 GT in 535i GT trim. The N55 will also come with High Precision direct injection helping to keep the engine both fast and efficient.

Last, but not least, BMW will also release the 528i, with a naturally aspirated 6 cylinder with an undisclosed displacement. The little inline-6 will produce 240HP – just a shade of 10HP over the existing ‘28i engine with its 230HP output. To keep with the EfficientDynamics model set out by its two bigger brothers, the engine will have heavy applications of magnesium and aluminum keeping the overall engine weight down. We expect that this engine will bear heavy ressemblance to the naturally aspirated N52B30 which debuted in the 5 Series with the 2006 and 2007 530i for  U.S. consumption. For those that remember, the N52B30 was designed to be a higher power, naturally aspirated inline-6 that could also return better fuel economy.

However, despite these terrific engines, power is nothing without control. BMW plan to give 8-speed transmissions to all of the 5 Series line-up. The 8-speed will likely be pulled straight from the existing 750Li and 550i GT making for a strong transmission that will allow the driver to experience all-round improved fuel efficiency with higher gearing while also allowing for better acceleration. The two taller gears in the 8-speed are ideal for cruising speeds and BMW has managed to improve the weight savings of the transmission to such a point that there is no additional weight added from the extra two gears. For those wanting to extract and put down power manually, a 6-speed gearbox will be available in the U.S. market for the bigger 535i and 550i.

Keep watch on this space as we’re going to continue to profile the many new elements of the F10 5 Series and we look forward to keeping you guys informed!

The all-new F10 5 Series is all but upon us now and this marks a new turning point in the history of the 5 Series and a continued change in direction for the designs and technologies of BMW. The original 5 Series was unveiled decades ago, an impressive high performer, with the production models going on sale in 1972 as BMW’s first mid-size executive sedan thus making the 5 Series line-up 37 years old and the oldest moniker in BMW’s existing line-up.

So, as you can imagine, the F10 5 Series has 37 years of success as well as pressure to shoulder as the 5 enters its new stage of life and sixth iteration.

It goes without saying, the F10 is the most technically advanced 5 Series to date. BMW has packed full the new midsize sedan and delivers in spades with the performance in terms of the engine line-up that the U.S. market can expect with the F10 platform. The line-up in terms of naming will not change from the existing E60 550i, 535i and 528i but buyers can expect wonderful surprises under the carefully sculpted hood.

The existing 4.8L V8 from the E60 will be replaced by the current 750Li’s N63 4.4L twin-turbocharged V8 producing an impressive 400HP with 450 lb-ft. The new 550i is expected to return a 0 to 60 sprint of 5 seconds flat – very impressive considering that’s the same sprint time of an E39 M5! With the twin turbo technology, the N63 manages the difficult balancing act of handing over heavy-hitting performance figures while returning respectable fuel economy for even those of us with the heaviest of right feet.  However, the engine does without the Valvetronic system of the previous E60 4.8L V8 as a result of the turbochargers keeping the intake pressurized. Additionally, BMW is able to keep the overall turbocharged V8 package much more compact by placing the catalytic converters between the cylinder banks and thus keeping the turbo plumbing to a minimum.

As impressive as the top-of-the-line V8, BMW will be providing the public with two staggered, high revving inline-6 cylinder engines. The new N55 engine will carry the 535i moniker from a twin-turbocharged 3.0L inline-6 to a single twin-scroll turbocharged 6 cylinder though, incredibly, without sacrificing power or efficiency. In fact, according to engineers, the single turbo N55 manages to produce serious power as low in the rev range as 1,200 RPMs thereby trumping the twin-turbo N54 lump by 200 RPMs. In speaking with BMW directly, we were told that the N55 will only have a slight weight penalty of perhaps 4 or 5 pounds over the N54 – so there isn’t much lost in that second turbo. However, where the N55 really shines is that, aside from producing 300HP like the N54, it manages to shed one of the turbochargers and pick up the throttleless Valvetronic system thereby increasing throttle response while reducing emissions and improving fuel economy. The N54 is an award winning engine and rightfully so, but, there will no doubt be resistance to the loss of the N54 to the N55. Once behind the wheel, it is expected that most drivers will not be able to notice the difference. BMWBlog expects the 3.0L twin-scroll turbocharged 6 sometime in the early to mid Spring also around when it will hit with the 5 GT in 535i GT trim. The N55 will also come with High Precision direct injection helping to keep the engine both fast and efficient.

Last, but not least, BMW will also release the 528i, with a naturally aspirated 6 cylinder with an undisclosed displacement. The little inline-6 will produce 240HP – just a shade of 10HP over the existing ‘28i engine with its 230HP output. To keep with the EfficientDynamics model set out by its two bigger brothers, the engine will have heavy applications of magnesium and aluminum keeping the overall engine weight down. We expect that this engine will bear heavy ressemblance to the naturally aspirated N52B30 which debuted in the 5 Series with the 2006 and 2007 530i for  U.S. consumption. For those that remember, the N52B30 was designed to be a higher power, naturally aspirated inline-6 that could also return better fuel economy.

However, despite these terrific engines, power is nothing without control. BMW plan to give 8-speed transmissions to all of the 5 Series line-up. The 8-speed will likely be pulled straight from the existing 750Li and 550i GT making for a strong transmission that will allow the driver to experience all-round improved fuel efficiency with higher gearing while also allowing for better acceleration. The two taller gears in the 8-speed are ideal for cruising speeds and BMW has managed to improve the weight savings of the transmission to such a point that there is no additional weight added from the extra two gears. For those wanting to extract and put down power manually, a 6-speed gearbox will be available in the U.S. market for the bigger 535i and 550i.

Keep watch on this space as we’re going to continue to profile the many new elements of the F10 5 Series and we look forward to keeping you guys informed!