That's a nice looking animation but unfortunately, is very misleading. From the animation, it looks like the fuel is injected AFTER TDC and what's the deal about 'compressed air' up at the injector?

Technical illustrators have a huge responsibility to 'get it right', particularly on a site like How Stuff Works where literally thousands of people will look at it and assume that, because it was on the 'net' it must be correct.

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