Download [PDF] 3.1 MB - ebm-papst UK

Modern technology enables a new approach to solutions in the automobile industry:Modern technology enables a new approach to solutions in the automobile industry:LED headlights require special fansLED headlights requirespecial fansModern materials andproduction methodsallow a variety ofapplications.Thanks to the brighter more powerful light,LED chips can now also be used for vehicleheadlights. With their long service lifeand compact size, they are increasinglybecoming an interesting alternative tohalogen or gas-discharge lamps es -pecially as they are mechanicallyextremely robust. The high degreeof efficiency also saves energy andthus fuel. How ever, as the activechip surface is extremely small,it must be well cooled. In particular,fans specially optimizedfor the requirements of vehicleheadlights enhance the requiredairflow and thus support activecooling. High reliability and longservice life are compulsory forall headlight components.Extremely bright LEDs operate high -ly efficiently. In comparison theyrequire less space and thus openup new design possibilities for head -lights and the front fascia of vehicles.This is one reason why the premiummanufacturer Cadillac is now relying ona full LED headlight for a high-beam, lowbeamand daytime running light manufacturedby Hella in its Escalade Platinum model.The light specialists cooperated with the fanspecialists ebm-papst from St. Georgen in theBlack Forest to provide the indispensable activecooling. Thus, a completely new type of headlightemerged with interesting technical innovations withregard to electronics, optics and cooling air supply (Image 1).Sophisticated motor vehicle applicationAll components in automobiles constantly suffer fromvibration, acceleration and oscillation, e.g. due to potholes.There is also an extremely wide temperature range inwhich all components are required to function reliably.The Escalade is fitted with a headlight package, comprisingthe casing and an array of 7 LEDs, a corresponding projectionlens of optical glass as well as the air leading insertthat is so important for the cooling and the actual fan itself.The colour temperature of the LEDs is approx. 5.500 Kelvinand is thus considerably closer to daylight with approx.6.000 K than light produced by Xenon bulbs with approx.4.000 K and they are not as strainful on the eye. As theheadlight is designed as a unit, the optical values must notalter before, during and after assembly. This requiresspecial handling during the manufacture and installation ofthe components.Tailor-made fansSpecial plastics were chosen to avoid degassing. The fancomponents are manufactured in the usual manner byinjection moulding, however, the melting point of the resis -tant material is considerably higher, so that the injectionmoulding system had to be converted from water coolingto oil cooling and the cycle times adapted accordingly.Even minor details that are important after successful testruns for series production, had to be kept in mind. Accordingto Michael Weißer, member of the development team:“Attention must be paid even to the most trivial things, i.e.marking the fans to ensure the high reliability of the entiresystem. Individual components must be traceable, yet thestandard solution of a label with numbers or barcode wasnot practicable. The direct marking of the fans solved theproblem.”Image 1: Full LED headlight by Hella for the Cadillac Escalade Platinum.1415