Gasoline Engine Configurations
The V-type of engine has two rows of cylinders at (usually) a ninety degree angle to each other. Its advantages are its short length, the great rigidity of the block, its heavy crankshaft, and attractive low profile (for a car with a low hood). This type of engine lends itself to very high compression ratios without block distortion under load, resistance to torsional vibration, and a shorter car length without losing passenger room. In 1914, Cadillac was the first company in the United States to use a V-8 engine in its cars.
In-line engines have the cylinders arranged, one after the other, in a straight line. Almost all four cylinder engines are inline engines. There are some five and six cylinder inline engines, which are mainly found in European cars.
Flat (Horizontal-Opposed) Engines
A horizontal-opposed engine is like a V-type engine that has been flattened until both banks lie in a horizontal plane. It is ideal for installations where vertical space is limited, because it has a very low height. Flat engines are usually either four or six cylinders, and have been used by Porsche and Subaru.
The rotary, or Wankel, engine has no piston, it uses rotors instead (usually two). This engine is small, compact and has a curved, oblong inner shape (known as an “epitrochoid” curve). Its central rotor turns in one direction only, but it produces all four strokes (intake, compression, power and exhaust) effectively. Although it is widely known that Felix Wankel built a rotary engine in 1955, it is also a fact that Elwood Haynes made one in 1893!
Dispensing with separate cylinders, pistons, valves and crankshaft, the rotary engine applies power directly to the transmission. Its construction allows it to provide the power of a conventional engine that is twice its size and weight and that has twice as many parts. The Wankel burns as much as 20%% more fuel than the conventional engine and is potentially a high polluter, but its small size allows the addition of emission-control parts more conveniently than does the piston engine. The basic unit of the rotary engine is a large combustion chamber in the form of a pinched oval (called an epitrochoid). Within this chamber all four functions of a piston take place simultaneously in the three pockets that are formed between the rotor and the chamber wall. Just as the addition of cylinders increases the horsepower of a piston-powered engine, so the addition of combustion chambers increases the power of a rotary engine. Larger cars may eventually use rotaries with three or four rotors.
In 1900, at the first National Automobile Show in New York City, visitors overwhelmingly chose the electric car. Most people thought the gasoline engine would never last. One critic of the engine wrote that it was noisy, unreliable, and elephantine; that it vibrated so violently as to “loosen one’s dentures.” He went on to give the opinion that the gasoline motor would never be a factor in America’s growing automobile industry. People were afraid that gasoline engines would explode. Motorweek magazine referred to them as “explosives.” At the show, a bucket brigade was standing by every time an “explosive,” was cranked. However, just three years later, at the same show, the number of cars with four-stroke internal combustion gasoline engines had risen sharply. Within a number of years, internal combustion engines would power virtually 100% of automobiles and trucks.
However, with the rise of technology and the demand for more environmentally friendly engines, electric engines have been resurrected.
Mid-engine sports coupes have the engine mounted in front of the rear axle. Passenger space is limited to two people. Concentrating the weight in the center of the car improves handling.
The conventional sports coupe’s engine is in the front of the car, driving either the front or rear wheels. This layout reduces production costs, but luggage space and rear seat room are sacrificed for the sporty styling.
Vans have engines located in either the front or the rear. Contemporary sedans have the engine in the front driving the front or rear axle.