It’s really not too complicated. There is a certain amount of energy contained in a gallon of gasoline, and it takes a certain amount of energy, and thus gasoline, to safely push an automobile, carrying people and their stuff, over the ground and through the air a given distance at a given speed, and to do so in a structure that won't crumple like an origami boulder upon contact with other vehicles or fixed objects (Smart cars seem a little less so when folded under a semi-trailer).
Understand that only
part of the energy in a gallon of gasoline is actually utilized in moving the car. Much of the energy is lost - through heat loss, mechanical friction, wind resistance, and tire friction
and flex. Even noise and vibration is lost energy. And much of
what isn't lost must charge the battery, provide spark to the engine, and power the air conditioning and all those
accessories (like Junior and Sissy's DVD players and those front seat bun warmers you paid extra for. Not that there's anything wrong with that). Even the energy that actually drives the car is eventually dissipated as heat through the brakes. Seriously, the
carburetor (or fuel injection today) is not the issue.
|"I know, but I'm getting wicked fuel economy."|
Engineers maximize efficiency (minimize energy losses) as much as possible, but no mechanical system is 100% efficient, meaning there are always energy losses. Which is exactly why true perpetual motion machines are an impossibility, the crest of each rise on a roller coaster is lower than the previous one and if you spin the most perfectly balanced and adjusted bicycle wheel it will eventually come to a stop. And because there are always energy losses, there is an upper limit to fuel efficiency and that limit is a lot closer to the highway fuel mileage of a Honda Civic than to a mythical 200 mpg.
All of that awful waste may sound positively medieval, but the truth is, the internal combustion engine is still an engineering marvel that has been refined to fuel efficiency and emissions levels only dreamed of just a few years ago. We're in the midst of a second Golden Age of high performance, only this time clean and economical performance. (More on that another time.) Electric cars and other alternatives are a real improvement in efficiency, but don't kid yourself; there is still noise and emissions and heat involved, it's just been moved upstream to the coal-fired power plant, conveniently out of sight and out of mind. Internal combustion and alternate energy will exist side-by-side for years to come, like mechanical and electronic wristwatches. At least until someone figures out how to make a solar-powered airliner.