5-15 Internal Combustion Engines

Let's look at how an internal combustion engine works.  Air and gasoline are mixed in the carburetor and turned into a vapor.  When a piston inside one cylinder moves down, the vapor mixture is drawn into the cylinder through a valve.  This valve then closes and the piston moves up.  It squeezes the vapor into a small space at the top of the cylinder.  There is a spark plug located at the top.  Notice the spark plug in the diagram below.

Just when the piston almost reaches the top of the cylinder, the spark plug lets off an electric spark.  This spark causes the vapor to explode.  This explosion forces the piston down to the bottom of the cylinder.  As the piston moves back up the cylinder for the second time, it forces the leftover gases out of the exhaust valve.  This ends the cycle and a new cycle begins.  This is called a 4 cycle internal combustion engine.

The pistons in the internal combustion engine are attached to a crankshaft.  This up-and-down motion is changed into a turning motion or rotation.  The differential and the axle transfer this mechanical energy of the turning motion to the wheels, and the vehicle is moved by the power of the pistons.

1. In an internal combustion engine, the fuel is burned

outside the engine.

by another engine.

within the engine.

None of the above.

2. The crankshaft changes the up and down motion from the pistons to

a sliding motion.

a turning motion.

a sideways motion.

All of the above.

Put the steps of how an internal combustion engine works in the correct order.  Number 1, 2, 3, etc.

The piston moves back up the cylinder forcing the leftover gases out of the exhaust valve.

The valve closes and the piston moves up.  It squeezes the vapor into a small space at the top of the cylinder.

When the piston almost reaches the top of the cylinder, the spark plug lets off an electric spark and causes the vapor to explode.

Air and gasoline are mixed in the carburetor and turned into a vapor.

The explosion forces the piston down to the bottom of the cylinder. 

A piston inside one cylinder moves down and the vapor mixture is drawn into the cylinder through a valve. 

The vehicle moves!

The up-and-down motion of the pistons is changed into a turning motion. 

The differential and the axle transfer the mechanical energy of the turning motion to the wheels.