BMW working on vehicle heat management to help reduce fuel consumption and CO2 emissions

BMW is currently working on new technologies to better manage heat released from its vehicles. By improving heat management, fuel consumption and CO2 emissions can be reduced. Even a very fuel efficient engine can only convert about one-third of the energy contained in fuel to actually propel a car.

The rest is lost as waste heat via the car’s exhaust and radiator. To be more specific the auto maker is working on three systems including technologies to eliminate cold starts, convert heat from a car’s exhaust into electricity and use waste heat for interior heating.

To eliminate cold starts, BMW is working on improving heat insulation of engines (pictured below) that can help prevent them from cooling down quickly and retain as much residual heat as possible for the next start. With the technology that is being developed, the engine will take longer to cool down and even after 12 hours, engine temperature can still be figured at about 40 degrees Celsius.

BMW claims that each degree Celsius above the ambient temperature can help reduce fuel consumption by 0.2%. To help achieve better heating, a vehicle will be surrounded by fully clad walls and panels using materials that are normally used in the car’s underfloor for insulation.

Heat can also be converted into electric power. The automaker says that between 3 and 8% of the total fuel consumed by modern cars is due to the rising number of electricity-dependent features. BMW is testing a component called a thermoelectric generator (pictured below).

This generator uses the effect of the temperature gradient in thermoelectric semi-conductor elements generating electrical voltage (the Seebeck Effect). The bigger the difference in temperature, the higher the voltage generated. Exhaust gas temperatures, which are usually between 300 and 900 degrees Celsius, are on the hot side of the generator, and engine coolant is used for the cold side.

Basically up to 250 W of energy can be produced by integrating the component with the exhaust gas recirculation cooler. 250 W equals to about half the on-board electricity consumption in a BMW 5 Series. This can help reduce fuel consumption and CO2 emissions by up to 2%.

The final technology of the heat management idea is an exhaust gas heat exchanger. This system can be placed close to the catalytic converter and it can convey heat to other components or areas like the interior. It can replace the need for electrical heating modules which consume additional fuel (by about 1 litre per 100 kilometers).

Furthermore, the feature can also be used to help warm up components like the transmission (example, oil in the automatic transmission). The above mentioned technologies are in testing stages hence it can take years before we can actually see them in production cars.

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Harvinder Sidhu

Harvinder Singh Sidhu thinks there's nothing better than Formula 1, not even sliced bread. Having written about cars since 2006, he plunged head first into the industry out of a passion for all things four-wheeled and everything in between. The F1 enthusiast has been following the sport since 1999 and has been keeping up with it since. In between races he keeps himself busy as the host of the Driven motoring show and as our version of the Joker.

 

Comments

  • scanzew on Oct 22, 2009 at 6:31 am

    my dream car!!!!white colour huhu

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  • scanzew on Oct 22, 2009 at 6:33 am

    bmw 320d…nice 0-100km/h at 8 sec….haha just refer column besides

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  • Jimmy Dean on Oct 22, 2009 at 7:14 am

    High temperature peltier chip used as thermoelectric generator is a good idea. However, at present the maximum energy conversion efficiency is about 8% and you have to maintain a really large temperature difference accross the thin peltier chip. If let say 30% of the energy is loss as heat through the exhaust gas and we can recover only 8% of that. For a 150 kW engine, 30% is 45 kW and if let say we can only recover a fraction, maybe 20% of the theoretically possible 8% efficiency (you can't cover the whole engine and the exhaust with peltier chips). So perhaps we can recover: 20% x 8% x 45 kW = 720 Watt from the exhaust gas waste heat. Perhaps enough to provide additional power for the entertainment systems or GPS or some other things.

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  • shawal on Oct 22, 2009 at 8:08 am

    Daihatsu is working on a 2 cylinder turbo engine on a small car that prolly can go 100mpg, y not combine that engine plus 2 extra cylinder more (lightweight), sort of on-demand power, when more ppl are inside the car, going uphill to genting… and the computer wizadry to calculate all the power needed is powered by this BMW technology. I'm from KL and a big car is pointless, however, My zippy (RM40 a week on fuel) savvy does feel very2 sluggish when more than 2 ppl on-board. The future is still petrol!

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  • bobdbilder on Oct 22, 2009 at 8:08 am

    Try making the car lighter and you reduce the need for more power. All BMW wants is to put more value added USPs to the car, and ends up putting more weight to the car. I wonder if it had tried using light alloys for the chassis. Or a 2 stroke engine? You know, less moving parts, less friction…

    All those expensive developments would not benefit us in the tropics though

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  • bobdbilder on Oct 22, 2009 at 8:11 am

    I mean the heat management stuff. Some Czech guy already has a patent in the 90s to actually convert heat to assist the engine.

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  • mystvearn on Oct 22, 2009 at 11:11 am

    Looks like what BMW is doing is placing their engines in one big thermos, then when you need it, the heat is still there. Not so sure about the heat to electricity part as the heat is conserved to warm the engine right. So how will the same system work to generate electricity? Also, I think that kind of technology will be a bit pointless in Malaysia since its always hot…

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  • binarumah.com on Oct 22, 2009 at 2:56 pm

    This is what I like about the Germans. They keep on thinking of other possible opportunities to make things better. Hmm..but big company like BMW of course la can do this kind of research.

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  • overheating?

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  • Great idea for cold countries…. how about the people in South East Asia….

    were heat is one of the cause of engine & transmission failure. Is BMW going to install aircon in the engine compartment. Ha ha ha….. Anyway were just small revenue channel for BMW AG so we are not priority. cheers….

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  • azrai on Oct 23, 2009 at 12:47 am

    Even cows release so many CO2. Haha.

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  • Jimmy Dean on Oct 23, 2009 at 3:51 am

    It is not pointless as the exhaust engine temperature is really in the range of several hundreds degrees celcius compared with relatively low outside air temperature range between 0 and maybe high around 50 deg C. So the temperature diffrence might be around 300 deg C in winter and just 250 deg C in summer or in middle east. The material used is typically special type of alloy which has p-n junction (electron rich on one side and electron deprived on the other side). When heated the electrons jump into higher energy level and move accross the p-n junction and you have electricity. Typical type of alloy used is bismuth telluride. The tricky part is not the heat source but how to maintain high temperature difference to get maximum current output accross the p-n junction. Typically water jacket and small radiator system is used to carry the heat away from the thermoelectric chip.

    One possible use of the peltier chip is to power up a blower fan over the barbecued satay, heat source from the satay fire.

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  • we need extra cooling here.not contain more heat

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