Engine vs Motor: What Is the Difference?
In everyday speech the words get mixed up, but engineers draw a clear line. An engine makes motion by burning fuel, like the petrol engine in most cars. A motor makes motion from electricity using magnets, like the motor in an electric car. You can look inside an electric car in the 3D Machine Anatomy simulator.
Engine vs motor at a glance
| Engine | Motor | |
|---|---|---|
| Energy in | Fuel, such as petrol, diesel or gas | Electricity |
| How it works | Burns fuel so hot gas pushes pistons or spins a turbine | Magnetic fields push on coils or magnets to spin a shaft |
| Efficiency | A car petrol engine turns roughly a quarter to a third of its fuel energy into motion | Often around 90% |
| Moving parts | Many: pistons, valves, crankshaft, camshaft | Few: mainly the spinning rotor |
| Exhaust | Yes, from burning fuel | None |
| Noise | Loud | Quiet |
| Can run backwards as a generator | No | Yes, which is how electric cars recharge when braking |
How a petrol engine works
Most car engines run on a four-stroke cycle. A piston sucks in air and fuel, squeezes it, a spark sets it alight so the hot gas pushes the piston down, then the piston pushes the waste gas out. Thousands of these small explosions a minute turn the crankshaft and drive the wheels. Much of the fuel’s energy is lost as heat.
How an electric motor works
An electric car’s motor has a fixed outer part, the stator, with coils of wire, and a spinning inner part, the rotor. Electricity from the battery flows through the coils in a carefully timed pattern, making a rotating magnetic field that drags the rotor round. It gives full turning force from a standstill, which is why electric cars feel so quick.
Quick facts
- We still say motor car and rocket engine, so the words overlap in everyday use.
- Jet engines and rocket engines are engines, because they burn fuel.
- The first practical electric motors were built in the 1830s.
- Hybrid cars have both an engine and an electric motor.
- In an electric car, braking can feed energy back into the battery, called regenerative braking.
See the electric car in 3D
Engine vs motor questions
What is the difference between an engine and a motor?
An engine makes motion by burning fuel. A motor makes motion from electricity, using magnetism.
Does an electric car have an engine or a motor?
A motor. It runs on electricity from a battery and burns no fuel.
Which is more efficient, an engine or an electric motor?
An electric motor, which can turn around 90% of its energy into motion, against roughly a quarter to a third for a car petrol engine.
Is a jet engine a motor?
No. It burns fuel, so it is an engine.
Why do people say motor car?
The word motor was once used for any machine that made motion, and the old name stuck.
More face-offs: see all 3D comparisons.
The 3D Machine Anatomy simulator is made by Julian Neagu, a solo founder in London, as part of VisionVix Simulators. It is free to use in the browser on desktop and phone, with no sign-up.