
Dammit, even their engines are pretty!
I was asked this question at work, and could only come up with three engines; I’m sure there are more, so I therefore turn the question over to you, our astonishingly-well-read commentariat, to provide more answers.
Alfa-Romeo made a marketing point of this feature, so I am removing them as the low-hanging fruit. In their “Twin-Spark” engines, they utilized a dual spark-plug configuration, or eight spark plugs in a four-cylinder engine. The idea behind this is that it allows the engine’s timing to be set much more accurately, and allows for a more efficient fuel burn, and therefore an engine that can be run on a much more lean setting, using less gasoline.
This was actually a fairly common practice with Alfa-Romeo, so by all rights I should be removing their engines altogether, but let’s face it, Alfas are gorgeous, so feel free to list them all off with beautiful high-resolution images.
I can think of one other very common engine, and one not-so-common engine that used this technology. After that, it’s up to you guys!
[Remember the rules, lurk before leaping, and width="500" is your friend.]