BMW Researches Reusable Waste Heat

As the race to provide vehicles as environmentally friendly as possible picks up, manufacturers worldwide are looking into ways to reuse every energy waste a vehicle produces, be it heat or from braking. So is the case with heat, until recently one of the worst enemies of an internal combustion engine-powered vehicles.

BMW engineers are currently working into ways to harness the power that comes from heat, by studying several technologies and methods. The goal is to eliminate cold start and generate energy from reusing exhaust gasses.

“We want cars to warm up as quickly as possible, since higher temperatures mean less friction, less friction means less fuel consumption and, therefore, less CO2,” Andreas Eder, BMW Heat Management Pre-Development Projects chief was quoted as saying by the Auto Channel.

Whereas eliminating cold star conditions can be done rather easily, by encapsulating the engines (in one BMW prototype, the engine is completely surrounded by clad walls and panels), not the same can be said by converting exhaust into energy.

For this, BMW uses a thermoelectric generator, presented last year. The tweaks made to it since, allow for up to 250 W to be produced in normal driving conditions, half of the on-board electricity used by a 5 series, BMW says.

The generator uses the so called Seebeck Effect (the effect of the temperature gradient in thermoelectric semi-conductor elements generating electrical voltage). The higher the temperature difference, the higher the outputted voltage.

The technologies are still under development, even if some precursors, like air flaps in some current models, are already here. Still, advancements achieved thanks to the research, like the longer cooling time of the engine (40 degrees after 12 hours since stop), or the elimination of the electrical heating modules, promise to bring better mileage and reduced emissions in the vehicles to come.