Impellers in vehicles
Cars, jet skis, fire trucks and rockets: impellers keep them cool, push them along and feed their engines.
⏱ 6 min
- Everyday comparisonStep 1 of 6
Two fans facing each other
Put two desk fans face to face and switch only one on. After a moment, the second fan starts to turn — pushed by the air from the first.
That simple trick is inside millions of cars with automatic gearboxes. And it is only one of the impellers hiding in vehicles.
- ExplainedStep 2 of 6
Keeping the engine cool
A car engine gets hot enough to melt itself. The water pump — a small impeller turned by a belt or an electric motor — pushes coolant through the engine and to the radiator, non-stop.
When a water pump fails, the engine overheats within minutes. Electric cars have coolant pumps too, to keep their batteries at the right temperature.
- Try itStep 3 of 6
Automatic gearbox: pump meets turbine
In a , the engine spins a pump impeller that throws oil at a turbine connected to the wheels. The oil carries the power across, with no solid connection.
That is why an automatic car can sit still at a red light with the engine running: the oil just slips.
Challenge: Switch between “Pump impeller” and “Turbine”. In a torque converter, both are working at the same time — one on each side of the oil.
- ExplainedStep 4 of 6
More breath: the turbocharger
A uses the hot exhaust gas to spin a turbine. On the same shaft sits a compressor impeller that pushes extra air into the engine.
More air means more fuel can burn, so a small engine makes the power of a big one.
- WatchStep 5 of 6
Jet skis: an impeller in a tube
A jet ski has no propeller hanging underneath. A sucks water in through the bottom of the hull and a mixed-flow or axial impeller shoots it out of a nozzle at the back.
No exposed blades means it is safer for swimmers and can run in very shallow water.
- The impeller connectionStep 6 of 6
Fire trucks and rockets
A fire truck carries a big centrifugal pump — often two stages — to push water up ladders and through long hoses.
Rocket engines use : a turbine spins impellers at tens of thousands of RPM to force fuel and oxygen into the engine. The biggest ones deliver as much power as hundreds of cars — packed into something the size of a suitcase.
📌 Remember this
Vehicles depend on impellers: coolant pumps keep engines cool, torque converters pass power through oil, turbochargers compress air, waterjets push jet skis, and turbopumps feed rocket engines.