four-stroke engine
Typical car powerplant
A four-stroke engine completes one power cycle in four movements of the piston: intake, compression, combustion, and exhaust.
This design dominates automotive and small-engine applications—cars, motorcycles, lawnmowers.
The term distinguishes it from two-stroke engines, which complete the cycle in half as many strokes but burn fuel less efficiently.
The outboard motor was replaced with a cleaner four-stroke engine.
Reciprocating cylinder component
- crankshaftRotating engine shaft
- camshaftLobed rod operating valves
- valvetrainEngine valve operating system
- connecting rodPiston-to-crankshaft linkage
cylinder head · intake valve · exhaust valve · spark plug · timing belt · flywheel · oil pump · sump
Amount received or consumed
- compressionForcing into smaller space
- powerEnergy transfer rate
- exhaustUse up entirely
- ignitionStarting combustion process
combustion · valve timing · spark · TDC
Starting combustion process
- sparkTiny fiery particle
- compressionForcing into smaller space
- fuel injectionPressurized engine delivery system
- detonationExplosive ignition event
burn rate · octane · stoichiometry · thermal energy · combustion chamber · pre-ignition · knock · hydrocarbon
Vehicle efficiency rating
- thermal efficiencyUseful output per heat input
- emissionsSubstances released into air
- direct injectionFuel sprayed into combustion chamber
- turbochargingForced air compression
compression ratio · heat loss · fuel consumption · catalytic converter
Self-propelled passenger conveyance
- motorcyclePowered two-wheeler
- lawn mowerGrass-cutting machine
- generatorElectricity-producing machine
- outboard motorDetachable marine propulsion unit
go-kart · ATV · snowmobile · chainsaw · scooter · tractor · Honda
piston
Reciprocating cylinder component
- crankshaftRotating engine shaft
- camshaftLobed rod operating valves
- valvetrainEngine valve operating system
connecting rod · cylinder head · intake valve · exhaust valve · spark plug · timing belt · flywheel · oil pump · sump · gasket
intake
Amount received or consumed
- compressionForcing into smaller space
- powerEnergy transfer rate
- exhaustUse up entirely
ignition · combustion · valve timing · spark · TDC
ignition
Starting combustion process
- sparkTiny fiery particle
- compressionForcing into smaller space
- fuel injectionPressurized engine delivery system
detonation · burn rate · octane · stoichiometry · thermal energy · combustion chamber · pre-ignition · knock · hydrocarbon
fuel economy
Vehicle efficiency rating
- thermal efficiencyUseful output per heat input
- emissionsSubstances released into air
- direct injectionFuel sprayed into combustion chamber
turbocharging · compression ratio · heat loss · fuel consumption · catalytic converter
automobile
Self-propelled passenger conveyance
- motorcyclePowered two-wheeler
- lawn mowerGrass-cutting machine
- generatorElectricity-producing machine
outboard motor · go-kart · ATV · snowmobile · chainsaw · scooter · tractor · Honda
- enginesV8, turbine, outboard motor, electric motor, inline-six
- propulsionjet, rocket, thrusting, jets, rockets
- gasoline enginesspark plug, piston, cylinder, crankshaft, combustion chamber
- Minimotopocket bike, pit bike, throttle, handlebars, exhaust pipe
- small enginesoutboard motor
- boat propulsionpropeller, oar, sail, paddle, outboard motor
four-stroke engineelectric motor
Converts current to motion
steam engine · jet engine · turbine engine · fuel cell · gas turbine
four, stroke, engine, fours, fourth, fourths, fourteen, fourteenth, fortieth