four-stroke-cycle engine![click to hear](/images/speaker.jpg)
Combustion engine whose cycle (intake, compression, combustion, exhaust) requires two up-and-down movements of the piston.
exhaust ![click to hear](/images/speaker.jpg)
Phase during which the exhaust valve opens and the piston moves back up to expel the burned gases.
burned gases ![click to hear](/images/speaker.jpg)
Mixture of gases (carbon monoxide, nitrogen oxide and unburned hydrocarbons) filling the combustion chamber after the explosion.
exhaust valve ![click to hear](/images/speaker.jpg)
Part that opens to allow the burned gases to escape.
piston ![click to hear](/images/speaker.jpg)
Metal moving part in the cylinder and attached to the connecting rod; it compresses the air/fuel mixture, then receives the thrust from the burned gases.
combustion ![click to hear](/images/speaker.jpg)
Phase during which the expansion of the combustion gases pushes the piston downward, driving the rotation of the crankshaft.
explosion ![click to hear](/images/speaker.jpg)
Ignition of the air/fuel mixture produces a major energy release that pushes the piston downward.
intake ![click to hear](/images/speaker.jpg)
Phase during which the exhaust valve opens and the piston comes down and draws the air/fuel mixture into the combustion chamber.
cylinder ![click to hear](/images/speaker.jpg)
Chamber closed by two valves; in it, the piston moves and the air/fuel mixture is burned.
air/fuel mixture ![click to hear](/images/speaker.jpg)
Mixture prepared in the carburetor, containing an amount of fuel proportional to the amount of air entering.
intake valve ![click to hear](/images/speaker.jpg)
Part that opens to let the air/fuel mixture into the cylinder.
compression ![click to hear](/images/speaker.jpg)
Phase during which the piston goes up to compress the air/fuel mixture. At the height of the compression, the spark plug produces a spark.
spark ![click to hear](/images/speaker.jpg)
Spark produced when an electric current arcs between the two electrodes of a spark plug and ignites the air/fuel mixture.
crankshaft ![click to hear](/images/speaker.jpg)
Shaft consisting of a series of cranks, which convert the alternate rectilinear motion of the piston/connecting rod assembly into a continuous circular motion.
connecting rod ![click to hear](/images/speaker.jpg)
Articulated shank powered by the gas explosion; it transmits the thrust from the piston to the crankshaft.