In 2014, Daimler made 496,000 trucks, 295,00 vans and 33,000 buses equipped with diesel engines. (the company does not disclose how many diesels it produces in a year). If the company decided to equip all its diesel engines with in-house turbochargers, this could amount to a market of 824,000 units, a sizable volume to justify in-house manufacture.
It perhaps should be pointed out here that as a turboocharger can rotate at speeds far beyond what is require, or what it is safely capable of, its speed has to be controlled. A wastegate is the most common mechanical speed control system and is often augmented with an electronic boost controller. The main function of the wastegate is to allow some of the exhaust to bypass the turbine when the required boost pressure is achieved. The wastegate's absence, and the multiplicity of associated sensors required for its efficient operation, suggests Mercedes engineers have found a clever way to duplicate its effect by controlling turbne speed and optimising transient behaviour. Clearly, in the past Mercedes has suffered reliability issues of some kind in this area.
So why adopt in-house turbochargers? What is the real technical justification for the move? The answer appears to centre on one word Mercedes-Benz engineers mutter under their breath as they discuss their new turbochargers - reliability. Any hint of unreliability is not required for the 12.8-litre engine which has emission control based on SCR technology, EGR (using three of the six cylinders) and particulate filter to meet Euro V1.
The decision by Daimler at board level to make turbochargers is surely a message to the management of all vendors. Lurking in the background is the veiled implication that if vendor technology, quality, reliability, cost, etc., etc., fall short of Daimler's requirements, then the company will take action to bypass it and, if necessary manufacture it in-house. Turbochargers could represent the latest in a series of important lessons.
Meanwhile, BorgWarner's manufacturing facility in Seneca, South Carolina, this week received an Excellence in Quality Award from Honda North America. Since 2002, the plant has received 12 supplier awards from Honda, including seven for quality, four for delivery and one for engineering innovation.The plant supplies Interactive Torque Management all-wheel-drive technology for the Honda Pilot..