Q:

How do pistons work?

A:

Quick Answer

A piston is a cylindrical plunger that moves within a metal cylinder through the four strokes of the engine cycle: intake, compression, power and exhaust. While their motion is predicated on other engine parts and the mixture of air and fuel, the motion of a piston is central to the functioning of an engine.

Know More
How do pistons work?
Credit: Frédéric BISSON CC-BY-2.0

Full Answer

The following process describes how a piston works in a standard four-stroke engine. During the intake stroke, the piston is pulled down by the crankshaft. While this is happening, the inlet valve opens and allows fuel and air to mix. For the compression stroke that follows, the inlet valve closes and the piston moves back up the cylinder to compress the mixture of fuel and air. During the power stroke, the spark plug ignites the fuel and air mixture, which pushes the piston back down. For the final phase, the exhaust stroke, the outlet valve opens. Powered by the crankshaft, the piston is pushed back up the cylinder. This forces exhaust gases out the outlet pipe.

Piston rings are essential to the functioning of a piston, as they provide a seal between the piston and the cylinder to facilitate better motion. These parts also prevent leaking between the compression and sump compartments.

Learn more in Motion & Mechanics

Related Questions

  • Q:

    What is the meaning of "swept volume"?

    A:

    "Swept volume" is defined as the volume of fluid through which a piston or plunger moves when it makes a stroke in an engine, according to Oxford Dictionaries. The swept volume times the number of cylinders in an engine is known as the displacement, usually measured in liters. Calculating the swept volume is done by multiplying pi times the radius squared times the height of the chamber.

    Full Answer >
    Filed Under:
  • Q:

    How does a piston engine work?

    A:

    A piston engine, also known as a reciprocating engine, works by expanding hot gases (a mixture of air and fuel) within a cylinder in order to push a piston, which in turn rotates a crankshaft and generates power. Unlike early steam engines, modern piston engines do not require an external source of hot gases, hence they are known as internal combustion engines.

    Full Answer >
    Filed Under:
  • Q:

    How does a car engine work?

    A:

    As the piston in an engine moves down, a mixture of fuel and air gets drawn into the cylinder, which causes compression. This compression is ignited by the spark plugs, causing the exhaust valve to open to allow the burned fuel mixture to be sent to the exhaust system. An internal combustion engine needs a gasoline-to-air mixture of around 14.7 parts air to one part gasoline (by weight) in order to run efficiently.

    Full Answer >
    Filed Under:
  • Q:

    How does a Jake brake work?

    A:

    A Jake brake works by opening the exhaust valves when the engine's piston reaches top dead center of the compression stroke. The engine uses its momentum and energy to compress the air, and that energy is lost to the atmosphere when the exhaust valves are opened.

    Full Answer >
    Filed Under:

Explore