How many cylinders does an engine need?
One problem with the four-stroke design is that the crankshaft is being powered by the cylinder for only one stage out of four. That's why cars typically have at least four cylinders, arranged so they fire out of step with one another. At any moment, one cylinder is always going through each one of the four stages—so there is always one cylinder powering the crankshaft and there's no loss of power. With a 12-cylinder engine, there are at least three cylinders powering the crankshaft at any time—and that's why those engines are used in fast and powerful cars.