There are of course exceptions and minute differences among the internal-combustion engines on the market. Atkinson-cycle engines, for example, change the valve timing to make a more efficient but less powerful engine. Turbocharging and supercharging, grouped together under the forced-induction options, pump additional air into the engine, which increases the available oxygen and thus the amount of fuel that can be burned-resulting in more power when you want it and more efficiency when you don’t need the power. Diesel engines do all this without spark plugs. But no matter the engine, as long as it’s of the internal-combustion variety, the basics of how it works remain the same. And now you know them.