What Kinds of Automobile Engines Are There?

Primary drive engines for moving an automobile come in three main types: piston, electric and rotary. Automotive engines were once greatly varied (and experimental), but modern car manufacturers have standardized on the gasoline-powered, reciprocating piston engine. These engines have evolved, but still use the same basic design as they did at the turn of the 20th century.

Gasoline

Over 95 percent of the world's automobiles run with a piston motor, with only 15 percent of those powered by diesel; fully electric motor vehicles account for less than 2 percent of the world's transportation, other types even less. Other fuels can be used in a piston engine, such as propane or liquefied natural gas, but these are mostly in fleet or industrial applications. Gas piston engines dominate the automotive world, despite the fact that a piston engine can run on any fuel with the same properties.

Configuration

Piston engines are generally built into only a few configurations for general use: four-cylinder in-line, "V" oriented or in-line six-cylinder and "V" oriented eight-cylinder styles. Other types exist, such as V-10s, V-12s, horizontal fours and sixes, and in-line-three or five-cylinder models, all of which are relatively uncommon. Diesels are popular in trucks and high-torque applications, but are available for cars in limited availability as in-line-four and five-cylinder models.

Rotary

The rotary engine, based on two or three flat, gasoline-powered disks, has been limited by patent to Mazda (which only uses it in one model). This design was created by Felix Wankel in the 1950s, then used in limited production until the 1970s. The rotary engine was once touted as the replacement for the piston design, but the cost of a reliable rotary design kept it from becoming popular. Instead of using a valved combustion chamber to push down on a cylinder, the rotary uses oblong combustion pockets to keep an off-center triangular crank spinning. The bearings, gears and housing of this type of engine are expensive, and the forces applied to the surrounding parts were extreme. The construction cost, coupled with the unfortunate emissions control regulations in the U.S. during the 1970s, caused the high-polluting rotary engine to fall out of favor.

Electric

Electric motors are popularized as fast, non-polluting, but limited engines. The only real limitation on the electric motor is the storage of the electricity, which is cheapest as lead-acid batteries. Other battery types, such as Lithium Ion, give electric cars an increased range, but are costly. Patents and laws have also kept electric motors from becoming a replacement to piston designs. Some inventors have built solar electric cars, but these typically take too long to charge.

Alternates

Many experimenters have tried to use alternative means to power an automobile. Many turn out to be publicity stunts or hoaxes, but popular designs include compressed air pistons, weighted flywheels and jet turbines.

References

• Engine Types
• Car Engine