Higher mathematics – The associative law of the firing order
Can you count to six? Stupid question, you might think. After all, even gunslinger Cheyenne could do it in the classic "Once upon a time in the west". Nevertheless, the task is not as easy as it first appears – at least under the hood.
The cylinders of a combustion engine are usually numbered consecutively, so that each ignition cable can find its spark plug. You start on the side opposite the power output (colloquially known as the "front" in longitudinal engines) and then count backwards to the flywheel. For in-line engines, this method usually provides a clear result. But things get a little complicated with V-engines. Because it would be too nice if there were only one of two possible solutions that prevailed.
In Europe, it has become established to treat each cylinder bank as a separate small in-line engine: first the left one is counted, then the right one. Using the example of a V6, this means: cylinders 1, 2 and 3 on the left; cylinders 4, 5 and 6 on the right.
In Japan and the USA, on the other hand, it is customary to count the cylinders according to the position of their connecting rod on the crankshaft and to regard the V as a fanned-out in-line engine: left and right always alternate. A V6 would then have cylinders 1, 3 and 5 on the left and 2, 4 and 6 on the right.
This results in the curious fact that an American V6 with the firing order 1-2-3-4-5-6 and a European V6 with the firing order 1-4-2-5-3-6 fire in the same pattern from a purely spatial point of view, although it reads completely differently on paper. An American engine in a German car makes the confusion perfect. Of course, you know this when you change the ignition cables on your Opel Omega and don't wonder for days afterwards why the car only runs on two pots.
Of course, exceptions prove the rule here too: although from America, the Ford Motor Company counts its cylinders according to the European system.
