Good interview - BMW "main" competitor in internal discussions used to be MB. Not an.

[Zafiro]

Ex VP BMW Product Development Talks On Development Process, M, Turbos, Competition

About him:
Worked for 23 years at BMW
Headed development of the previous-gen X3 and the current-gen 6 series coupe and convertible.
Headed the BMW Hydrogen initiative and was responsible for building 100 7 serie Hydrogen capable cars.

About development of cars at BMW in general:
The process usually takes 60 months in total. 30 months to design the general car and mostly to develop the business case for it. 30 months to actually get all the technical development, tooling development and testing done.
Every model development is reported to BMW´s board about 5-6 times in the 30 month period.
You need to test the car in at least one hot summer location/one extreme winter. Cars can get shipped to many places in the world to achieve this.
One "large group" within BMW shares a lot of work on the 5,6 & 7 series (including GT). Another works on the 1 & 3 series and yet another on the X5/X6. Didn´t ask about where the X1/3 fall now that I think about them. Or the Z4. Or the MINI.
Very extensive testing is done at the Nurburgring. He has a special license that is needed when the car companies rent the car and close it down for testing.
The M division is now getting to work on their models earlier in the process, sometimes "in parallel" with regular series development. This was not the case before but BMW wants to reduce "lead time" to market for the M cars. The M division is basically free to do as it wishes with engine, suspension, body parts, etc (not chassis). However M cars need their own business case and should stand by themselves financially.

About the current 6 series:
The 6 convertible was launched first because the end of the development period and (launch) of the car was synced to Q1 and it was best to sell the convertible in the hot months in the northern hemisphere.
The main market for the 6 series is the U.S.
The EPS has been tuned on purpose to feel as soft as it feels. BMW feels that not all cars should be targeted to the enthusiast market as that represents a small part of their client base. It is not a limitation of the system itself, he says you can tune it with software to provide whatever level of feel you want to achieve for the car.
Proud of having launched fully LED headlights on the 6 series.
Funny anecdote: during the press launch in South Africa one journalist spent 20 minutes plus stuck on an uphill climb behind a truck at low speed. Thing is, for the whole time he kept the engine boiling at 6,000 revs behind the truck. So eventually he pulls out to pass and the overheated engine goes into limp mode immediately and the car loses power for the pass. No accident but this journalist was very angry. It is not easy to tell the guy that he can´t drive and that you shouldn´t stay at 6,000 revs for 20 minutes. In any case, BMW later duplicates the "issue" and decides to modify the limp mode software so that the car will shift much earlier (to protect itself) but not cut power (so that you can still pull off a pass, especially with the torque of the V8 biturbo).

About the Hydrogen 7:
100 cars were built
The plan was to drive each one for 80,000 km and then scrap it to learn about the technology. 3 they kept and are still in use and working fine.
The hydrogen tank alone cost more than 100,000 euros per car. It was completely bespoke as nothing existed at the time that met the safety requirements. Many other bespoke specific parts were designed and built for these cars.
All cars had very sophisticated telemetry that allowed BMW to check continually on their status from a central command center - for safety.
The Hydrogen tank needed to be kept below -230 C at all times to keep the liquified Hydrogen
The project was started when BMW thought that "peak oil" would be reached within the past decade. Peak oil is when the rythm of consumption per year surpasses the rate at which the oil companies add reserves. This hasn´t happened yet and it looks like we will still have oil for a while so the project is in the back-burner until it may make economic sense in the future
Hydrogen is an energy carrier only, more akin to a battery than to gasoline which is an energy container.

About the X3 (previous gen)
It was an interesting project because BMW did not have enough manufacturing capacity at the time and subcontracted the manufacturing to Magna-Steyr.

 

[Gianclaudio]

However, keeping the turbo engine cool at altitude is a special challenge. Basically because, at altitude, an N/A engine will produce less power than at sea level (and thus less heat) and that is proportional to the reduced cooling capacity of the whole system because of the thinner air (which can carry less heat to cool radiators, etc). However, a turbo engine will basically produce the same power at altitude as it does at sea level, thus the same heat that now has to be dealt with with radiators being cooled by the thinner air at altitude. And this costs a lot of money that may not be justified for the very small percentage of customers that see track conditions at altitude.

What a pile of BS !!!!!!

Being at a higher altitute, the enviroment is cooler; so there isn't extra heat problem

And:

that is proportional to the reduced cooling capacity of the whole system because of the thinner air (which can carry less heat to cool radiators, etc

The engine produce less power not b/c the "air carrying less heat to the radiators" but because at less pressure (higher altitude), the air carries less O2 molecules on the same volume of air than on sea level

Less O2, less efficient combustion, thus, less power.

Regards

 

[martinbo]

What a pile of BS !!!!!!

Being at a higher altitute, the enviroment is cooler; so there isn't extra heat problem

No it's not BS. It's not universally applicable that air at altitude is always cooler. Everything he says is correct from a motoring point of view. In the summer months on the Highveld plateau of SA temperatures often exceed 35 C. In the Northern Cape - Upington region where many manufacturers come to test - temperatures in excess of 40 C are not unusual during the summer months. We're talking elevations of 1600m-2000m - typical of the hot 'n high conditions being referred to and representative of the urban areas at altitude. We're not talking Alpine-plus conditions of 3000m or more.

The engine produce less power not b/c the "air carrying less heat to the radiators" but because at less pressure (higher altitude), the air carries less O2 molecules on the same volume of air than on sea level

Less O2, less efficient combustion, thus, less power.

He never said that the engine produces less power because of what you wrote as "air carrying less heat to the radiators". Read the sentence again:

Basically because, at altitude, an N/A engine will produce less power than at sea level (and thus less heat) and that is proportional to the reduced cooling capacity of the whole system because of the thinner air (which can carry less heat to cool radiators, etc).

So the statement logic reads as follows: produces less power (thus less heat) because of the thinner air and therefore the cooling requirement reduces proportionally.

Yes, you're right; less dense air means less oxygen thus less efficient combustion process. BUT a turbocharged engine compensates for this lack of atmospheric pressure by creating its own boost pressures and, at our altitudes, lose around 4-5% of power output compared to the 18-20% loss in a naturally aspirated engine. We have had major problems - especially with modern turbodiesels - up here in on the highveld as a result of turbocharger overspeeding, cooling systems failure and overheating. Simply put, the cooling system's capacity to carry cooler air is diminished because there's less of it whilst the engine is still producing much the same power and thus the same heat.

 

[Human]

Yes, you're right; less dense air means less oxygen thus less efficient combustion process. BUT a turbocharged engine compensates for this lack of atmospheric pressure by creating its own boost pressures and, at our altitudes, lose around 4-5% of power output compared to the 18-20% loss in a naturally aspirated engine. We have had major problems - especially with modern turbodiesels - up here in on the highveld as a result of turbocharger overspeeding, cooling systems failure and overheating. Simply put, the cooling system's capacity to carry cooler air is diminished because there's less of it whilst the engine is still producing much the same power and thus the same heat.

We have exactly the same problem in my industry (agricultural) where since the early 80's when Atlantis Diesel Engines (who manufactured PERKINS engines under licence) had to use Altitude Compensators (same as a Turbocharger just introduces less air/boost pressure) on N/A engines to compensate for the loss of power at altitude. The first changes that came with the introduction of Turbocharging on the (4Cylinder) 4-236T (Turbo) and 4-236C (Compensated) was heat.

Thus a new Piston was introduced called a Controlled Expand Piston and Rings. Inter-cooling and outer oil coolers where introduced together with Water pumps with larger impellers. Also the crankcase was fitted with an 'oil gallery' to which Oil Spray/Oil Cooling Jets was fitted to spray directly into the Cylinder Liners.

The same had to be done to the 6-354 and newer TIER II Engine series 1006 Engine - 6 Cylinders. ONLY IN SA!

Up to this day with the newest Diesel Tech from OEM's i.e. John Deere, Massey-Ferguson, Landini, McCormick etc. and Perkins Engines, CAT, Detroit Diesel, Mercedes-Benz, MAN, Volvo etc. who's engine technology far exceeds car engine technology and are all TIER III engines have overheating problems when introduced in the SA market. These calls for new engineering solutions before they can introduce engines to the SA market.

Most of the time this together with our poor quality Diesel fuel results in Engines to be 'down tuned' via their ICU's or computer controlled engine management and fuel systems. A John Deere 8000 ser tractor that was not yet 'tuned' to our working conditions will, when encountering any problems within pre-set specifications downgrade it's own power via it's ICU to prevent damage to itself (i6 9.5 Liter Twin Turbocharged machine) that was introduced to the market in 1998.

Just for interest sake that is

 

[Gianclaudio]

No it's not BS. It's not universally applicable that air at altitude is always cooler. Everything he says is correct from a motoring point of view. In the summer months on the Highveld plateau of SA temperatures often exceed 35 C. In the Northern Cape - Upington region where many manufacturers come to test - temperatures in excess of 40 C are not unusual during the summer months. We're talking elevations of 1600m-2000m - typical of the hot 'n high conditions being referred to and representative of the urban areas at altitude. We're not talking Alpine-plus conditions of 3000m or more.

But he's talking about Mexico city, at 2300m and which barely exceeds 27 C
I live in Bolivia, in the heart of South America, two of our main cities sit on 2000+ meters: Cochabamba at 2600 and La Paz at 3700. (Some roads pass the 4500m) I've never ever experienced nor heard of anyone suffering overheating in these cities, turbocharged or N/A engines aside. (I do now about the FI used to compensate for the loss of pressure, back to piston driven airplanes era)

Regards!

 

[chonkoa]

What a pile of BS !!!!!!

Being at a higher altitute, the enviroment is cooler; so there isn't extra heat problem

And:

The engine produce less power not b/c the "air carrying less heat to the radiators" but because at less pressure (higher altitude), the air carries less O2 molecules on the same volume of air than on sea level

Less O2, less efficient combustion, thus, less power.

Regards

Not BS as Martin have said- it is a fact.

 

[chonkoa]

What a pile of BS !!!!!!



The engine produce less power not b/c the "air carrying less heat to the radiators" but because at less pressure (higher altitude), the air carries less O2 molecules on the same volume of air than on sea level

Less O2, less efficient combustion, thus, less power.

Regards

With heat exchange, the key components are:
- temperature difference
-Mass of heat exchanging material.
-dissipation rate

At higher altitude, due to the low pressure your air density is low thus resulting in lower efficiency with heat exchange. You get the added benefit of better temperature differential but that is not enough to offset the part "mass" plays in cooling.

 

[Gianclaudio]

^
You forgot about area of heat exchanging.

Still, I've to insist:

But he's talking about Mexico city, at 2300m and which barely exceeds 27 C
I live in Bolivia, in the heart of South America, two of our main cities sit on 2000+ meters: Cochabamba at 2600 and La Paz at 3700. (Some roads pass the 4500m) I've never ever experienced nor heard of anyone suffering overheating in these cities, turbocharged or N/A engines aside. (I do now about the FI used to compensate for the loss of pressure, back to piston driven airplanes era)

Regards!

 

[chonkoa]

Yes, you're right; less dense air means less oxygen thus less efficient combustion process. BUT a turbocharged engine compensates for this lack of atmospheric pressure by creating its own boost pressures and, at our altitudes, lose around 4-5% of power output compared to the 18-20% loss in a naturally aspirated engine. We have had major problems - especially with modern turbodiesels - up here in on the highveld as a result of turbocharger overspeeding, cooling systems failure and overheating. Simply put, the cooling system's capacity to carry cooler air is diminished because there's less of it whilst the engine is still producing much the same power and thus the same heat.

Like you said, the Turbos compensate for the loss of power by increasing the pressure however the addition of the turbo like you rightly pointed out fails to address the heat exchange problem.
The mass of the cooling material (air) is still low thus creating heat exchange problems hence the need to augment the cooling system to facilitate heat transfer.

 

[martinbo]

It's as you say chonkoa. Fundamental principles.

 

[EMpower]

When it comes to US, I think Lexus is main competition.

 

[Guibo]

Some very good info in that thread. However,

The EPS has been tuned on purpose to feel as soft as it feels. BMW feels that not all cars should be targeted to the enthusiast market as that represents a small part of their client base. It is not a limitation of the system itself, he says you can tune it with software to provide whatever level of feel you want to achieve for the car.

If that is so, then the "enthusiast" feel should be available on the very same car as the normal feel. Should be just a matter of a button press or iDrive toggle away.

 

[Sunny]

But he's talking about Mexico city, at 2300m and which barely exceeds 27 C
I live in Bolivia, in the heart of South America, two of our main cities sit on 2000+ meters: Cochabamba at 2600 and La Paz at 3700. (Some roads pass the 4500m) I've never ever experienced nor heard of anyone suffering overheating in these cities, turbocharged or N/A engines aside. (I do now about the FI used to compensate for the loss of pressure, back to piston driven airplanes era)

Regards!

No, he is talking about lapping continuously at a race track located in hot and high conditions. Very different from just driving on normal roads even at a fast pace.

 

[Gianclaudio]

No, he is talking about lapping continuously at a race track located in hot and high conditions. Very different from just driving on normal roads even at a fast pace.

Didn't notice that. My bad.

Thanks mate

 

[Human]

Background of new research into Turbocharging


Although the title of this report refers specifically to turbochargers, which are superchargers powered by the pressure of the exhaust system, its scope also includes mechanically- or electrically-powered superchargers and the various combinations and subgroups of the three types that are finding their way into both the light and heavy vehicle powertrain sectors. As in common usage language, although turbochargers are a specific type of supercharger, the term ‘supercharger’ will be used to refer only to mechanically- or electrically-driven superchargers.

Superchargers and turbochargers have been deployed on internal combustion engines (ICE) since the early years of the twentieth century, and although they have remained in use on heavy commercial vehicle diesel engines, they went out of fashion for many years on gasoline engines until a resurgence during the 1970s when they were used to increase power output. More recently, with increasing pressure to improve fuel efficiency and reduce emissions of both greenhouse gas and criterion noxious exhaust substances, the technology has been applied to enable engine downsizing while maintaining similar power output.

Consequently, turbocharging and supercharging are now regarded as critical technologies within powertrain development.

Turbocharger Report examines the current market drivers affecting this sector including fuel economy and CO2 emissions, engine downsizing and criterion emissions.

The report goes on to provide market dynamics and forecasts for light-duty and medium and heavy duty engines and features a detailed section on the latest technologies in this sector.

Furthermore, the report considers the future of turbocharging and features the major market participants.

Source: reports@supplierbusiness.com

 

[Deckhook]

No, he is talking about lapping continuously at a race track located in hot and high conditions. Very different from just driving on normal roads even at a fast pace.

This makes me question whether it's a wise decision to bring the turbos in between the vee of the engine, I would have thought that cooling would be more of an issue there than anywhere else.

 

[martinbo]

Yes of course. Two piping hot turbos right next to each other surely presents a cooling problem. That's why BMW have implemented a water cooling system for the hot-side inside turbochargers.

 

[Sunny]

I guess the other option would to put the intercooler between the V like M157. Is that any better? I am not sure, cause now you have the intercooler in the V which probably effects it's ability to cool the intake charge down. Or they could put nothing in that space which would effect the engine's compactness - I guess it is all a trade off.

 

[Deckhook]

Yes of course. Two piping hot turbos right next to each other surely presents a cooling problem. That's why BMW have implemented a water cooling system for the hot-side inside turbochargers.

I guess the other option would to put the intercooler between the V like M157. Is that any better? I am not sure, cause now you have the intercooler in the V which probably effects it's ability to cool the intake charge down. Or they could put nothing in that space which would effect the engine's compactness - I guess it is all a trade off.

And that's why I am not an engineer, I have enough problems just getting my kids to eat their greens never mind finding a solution to the above.

 

[Human]

BORG WARNER

Future - Turbocharger for an exhaust temperature of 1050°C

The turbocharger is also becoming more and more accepted in connection with the gasoline engine. The advanced charging technique will cause the percentage of turbocharged vehicles to steadily increase. The exhaust temperatures of future turbocharged gasoline engines will increase. The air ratio ? at the rated output point is currently about ?=0.75–0.85 since a portion of the fuel is used to cool the inside of the engine. If the air ratio is increased to a value between ?=0.9-1.0, then a potential fuel savings of up to 20% can be attained. However, this leads to an increase in the exhaust temperature of up to 1050°C and places new demands on the turbocharger, among other things.

Turbochargers for exhaust temperatures of 1050 °C require a material for the turbine housing that will withstand such high component temperatures during the entire service life of the vehicle. Heat-resistant cast steel is ideal for this purpose. Turbine housings made of heat-resistant cast steel are already being used today by BorgWarner Turbo Systems for mass-produced customer engines.

In addition to the turbine housings, the increased exhaust temperatures also result in extreme conditions for the turbine wheels. In this case, as well, BorgWarner Turbo Systems can provide a solution thanks to continuous refinement of the materials and connecting technologies previously in use. The bearing housing was redesigned with a highly efficient water cooling system in mind. The V-band clamp was introduced to ensure a secure connection between the bearing housing and the turbine housing at high temperatures.

The thermal inertia of the turbine housing is of great significance to very low emission vehicles. Due to the low level of thermal inertia, the temperature in the catalytic converter during the cold-start phase of the engine rises quickly. The conversion of the pollutants in the exhaust starts early in this case. The thermal inertia and the surface area of the turbine housing are to be kept as small as possible to keep emissions low.

The thin-walled turbine housing

The complexity of the manufacturing and machining processes for turbine housings made of cast steel and the high costs arising in connection with them has raised the question of what benefits the customer derives from these technologies. Thin walls are desired to significantly reduce the weight of the turbine housing and simultaneously reduce the thermal inertia of the turbine housing. This leads to faster activation of the catalytic converter during the cold-start phase of the engine, which in turn significantly improves the emission levels of the vehicle.

The sheet-metal turbine housing

Another promising solution can be found in the form of an sheet-metal turbine housing. It consists of several stamped sheet-metal parts that are welded together. The turbine housing can have a single-flow or double-flow construction with air-gap insulation.

The turbine housing in the exhaust system of the engine can be connected to its exhaust manifoldes by a flange or the pipes can be welded on. As a result of this, it is possible to have continuous air-gap insulation for the flow of exhaust from the cylinder head all the way down to the catalytic converter. Heat resistant sheet metal is available as a material that permits exhaust temperatures of up to 1050°C. Aluminum turbine housings are just as good as cast turbine housings in terms of their efficiency and throughput, yet they have much less thermal inertia and therefore allow the catalytic converter to be activated faster during a cold start.

The newest generation of charging systems from BorgWarner Turbo Systems fulfills the higher demands of future gasoline engine generations in regards to turbocharging and provides the customer with solutions for all gasoline engine applications.