The engine is basically the main component of your vehicle that allows you to travel at speeds never thought of hundreds of years ago. The engine is comprised of many components but the core function is simply based on the combustion process of fuel and some type of oxidizer which is normally air in a compressed air chamber. Within this tight space temperatures are increased by a spark mixed with the fuel and sudden expansions allow the pistons to move up and down which generates a force strong enough to eventually make the wheels on a vehicle turn at speeds of excess of 150mph. The engine has evolved greaty over the years and things like fuel economy and emissions have forced manufacturers to produce more efficient, lighter, higher quality engines than in days past.
Normally foreign engine makers like Acura, Toyota, Nissan and Lexus have been know for putting out the best engines in the world when it comes to efficiencies and dependability but US engine makers like Chevy, Ford, and Dodge continue to dominate in the 'power' department. While each make has its distinct advantages and disadvantages it has never been a better time in history to have as many choices as car shoppers have today.