The BMW six-cylinder in-line engine belongs a little to the endangered species. It is still part of the brand identity and nevertheless will slowly displaced by the looming awareness of climate change. Model series in which it comprehensively occured earlier keeps clear for it yet just one place.
There were times when he powered every second new car at BMW. Since one has denoted the Munich production of four-cylinder engines therefore as technically so insufficient, in order to put the qualities of the six-cylinder in its true light. And what it has meanwhile reached it all?
Six-cylinder in-line engines have a long tradition at BMW. 1917/18 the company has nor the aircraft engines in the letterhead, there is the first engine - with the one wants compete with the dominant Daimler Group - an in-line engine with six cylinders, which even grabbed the (unofficial) altitude record.
1933, five years after beginning with the car manufacturing, we are once again arrived at this type of engine. Although not with overhead camshaft(s), but at least with overhead valves, not self-evident at the time. In the very successful BMW 328 the valves are even V-shaped. The engine helps to make BMW known as an innovative brand in this exalted class of vehicles.
In 1968, the brand has so far recovered from their crisis after the Second World War, that again a model with a six-cylinder engine comes on the market. This choice is also maintained, though by and by all other producers switch to the V-6 or start with this. Six-cylinder in-line engines there are virtually no longer nowadays except at BMW in the car sector.
The engine called 'M30' gets even with the 'M20' (Figure 4) a little brother and also appears as a diesel engine in 1983. It starts with a camshaft (OHC), will in the meantime developed further to dohc, now standard with four valves. Almost all available mixture preparations have accompanied it, from the two stage carburetor and twin carburetor via the K- or rather L-Jetronic to the present engine management.
The manufacturer's effort to keep this engine fit under all circumstances, have led to a steady increase in performance while reducing fuel consumption. The diesel just reached four times the performance and three times the torque compared to the values at its first appearance. There are completely disregarded the racing engines.
However, the charging is a great help. How difficult was the introduction in the gasoline engine in the early seventies at the time of the oil price crisis. Today, in principle to that time comparable technology has a very different task. Meanwhile, it is very helpful in the reduction of CO2. But the downsizing associated therewith could cost the engine the right to exist.
Long since not only one charger is working together with this engine. It is also no longer just a turbo (images 1-3). So mechanical and exhaust-driven supercharger operate harmoniously sometimes parallel, sometimes in series with possibilities for bypass. Latterly, they even occur to third. Oh, and I still have forgotten the possible charging by electric motor. However, these only cover a small range.
How fortunate that at a R-6 is significantly more space on the suction side than at a V-6. With four valves per cylinder are also needed only a maximum of two camshafts. Of course, the newer R-6 from BMW also have the whole package of engine control, fully variable up to valve lift. For a V-6 would be needed some duplication.
But, we still have a small glimmer of hope for you. What began with the airplanes maybe it ends up with the motorcycles (pictures below). Although the six-cylinder not even seems to be suitable for the motorcycle at first glance, it will built and sold. Here then at last it is allowed to carry out its task transversely and the lovers of this engine-species are even closer to him. Well, that's any consolation? 08/13