Compared to other
technologies we use every day, it seems like car engines haven't really changed
much. The engine in an old Ford Model T has plenty in common with the engine in
a 2011 Ford Fusion, but it's doubtful Alexander Graham Bell would know what to
do with an iPhone. While communications technology has changed drastically, car
engines use the same basic principle: The combustion of air and fuel to create
rotational force and move a car.
But while the same basic
principles that drove the first car engines are still used today, modern car
engines have evolved to meet the power and efficiency needs of today's drivers.
Think of older car engines as wolves and modern car engines as dogs. They're
share the same heritage and have similar characteristics, but one does just
fine in everyday modern situations, while the other just couldn't adapt to
living in a city or suburb.
Before we talk about how
modern car engines are different from older ones, you need to understand the
basics of how a car engine works. Basically, gasoline and air are ignited in a
chamber called a cylinder. In the cylinder is a piston that gets moved up and
down by the gasoline/air explosion. The piston is attached to the crankshaft.
As the piston moves up and down, it makes the crankshaft rotate. The crankshaft
goes out to the transmission, which transmits that power to the car's wheels.
Sounds simple, right? With modern engines the basics still apply, but there's a
lot more to think about.Your basic gasoline car engine isn't all that efficient.
Of all the chemical energy in gasoline, only about 15 percent gets converted
into the mechanical energy that actually moves the car. The EPA says over 17
percent of the energy is lost as the engine idles, and a whopping 62 percent is
lost in the engine due to heat and friction.
Modern engines have a number
of technologies in place to make them more efficient. For example, direct
injection technology, which mixes the fuel and the air before they're put into
the cylinder, can improve engine efficiency by 12 percent because the fuel
burns more efficiently [source: U.S. Department of Energy]. Turbochargers,
which use compressed air from the car's exhaust system, compress the air that's
used in the combustion cycle. The compressed air leads to more efficient
combustion. Variable-valve timing and cylinder deactivation are technologies
that allow the engine to use only the fuel it needs, increasing efficiency.
There's a common
misconception that efficient engines are underpowered engines. Keep reading to
learn how modern engines out-muscle their older counterparts
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