Piston Ring Museum

Engine Structure & Operation

Engine Structure

If you have ever looked under the hood of a modern passenger car, you already know that today's automotive engines are hidden under covers, housings, wires, hoses, and complex control systems that make it impossible to see the engine's inner workings (structure).

To make this structure easier to understand, we have presented a drawing to show the basic moving parts of a modern passenger car engine.

Place the mouse cursor on each of the component names.

Engine Structure

  • Timing gear

    Timing gear

  • Timing belt

    Timing belt

  • Camshaft


  • Piston


  • Connecting rod

    Connecting rod

  • Crankshaft


  • Bearing cap

    Bearing cap

  • Starter motor

    Starter motor

  • Flywheel


  • Valve


  • Valve spring

    Valve spring

Cited from"Enjin ha kounatteiru エンジンはこうなっている" (Grand Prix BOOK PUBLISHING CO.LTD.,)

Engine Operation

We will begin our explanation of basic engine operation by looking at the four-stroke working cycle of the engine. These four strokes are usually called(1) the intake stroke, (2) the compression stroke, (3) the combustion (expansion) stroke, and (4) the exhaust stroke.

Let's take a look and see how a typical four-stroke engine operates.

How a four-cycle engine works

Cited from"Enjin ha kounatteiru エンジンはこうなっている" (Grand Prix BOOK PUBLISHING CO.LTD.,)

The piston goes up and down twice (four strokes) during the cycle, sucking in ambient air (mixed with fuel), and then burning it to produce expanding gases that drive the piston down, producing engine output. The resulting gases can reach temperatures of over 800.

Now we are ready to look at the piston ring and to learn about its important function in the engine.