A hybrid vehicle is any type of vehicle that combines two or more sources of power. There are all types of hybrids.
Locomotives on trains are diesel-electric hybrids. Some cities like Elk Grove, California, and Seattle, Washington, have buses that are hybrids. In Seattle they get electric power from overhead wires or they can run on diesel when there are no wires. In Elk Grove, just south of Sacramento, most of the E-Tran bus fleet use electric motors for very low speeds, and when the vehicle is stopped the gasoline motor shuts off.
Ships on the ocean are hybrids, burning oil to run generators that power huge electric motors. Submarines are also hybrid vehicles, most being nuclear-electric.
The "newest" kind of hybrid is the gasoline-electric hybrid automobile.
There are two forms of hybrid cars.
The first is called a "parallel hybrid." It has a small internal combustion engine. It also has batteries that power an electric motor. Both the engine and the electric motor can power the vehicle's transmission and wheels.
The second is called a "series hybrid." The gasoline engine runs a small on-board generator to produce electricity. The generator can either charge batteries or power an electric motor that drives the transmission. The gasoline engine never directly powers the vehicle.
What about the cost of a hybrid? While the initial cost may be higher, with good driving techniques and the higher mileage, the hybrid should pay itself back in a few years in gasoline saved.
Energy Efficiency is the Key
The gasoline engine in a hybrid is usually much smaller than the one in a regular car and therefore can be more efficient.
Let's compare a "muscle car," the Ford Mustang GT, to a hybrid.
2005 Mustang GT
4.6-liter, V-8 engine - generating 300 horsepower at 5,750 rpm.
It does 0 to 60 mph in 5.1 seconds, with a quarter-mile top speed of 103.6 mph.
It weighs 3,520 pounds.
EPA mpg city/hwy: 18/23 (automatic transmission)
1.5 liter gasoline 4-cylinder engine plus electric motor
76 hp at 5,000 rpm for gasoline, 67 hp at 1200-1540 rpm for electric.
0-60 in 10.2 seconds, with a quarter-mile top speed of 78 mph.
It weighs 2,921 pounds.
EPA mpg city/hwy: 51/60
The engine in the Mustang is sized for the peak power (flooring the accelerator pedal for fast acceleration). Most drivers, however, only use peak power less than 1 percent of the time if at all. The hybrid Prius uses a very small engine, which is sized closer to the average power requirement, and if it needs extra, peak power, the electric motor can kick in. Therefore, it gets almost three times more than the fuel economy of the Mustang.