INTERNAL COMBUSTION ENGINES. EXTERNAL VS INTERNAL external- combustion engine typically steamed...

INTERNAL COMBUSTION ENGINES

EXTERNAL VS INTERNAL

external- combustion engine typically steamed powered heated water would produce steam to increase pressure

in a piston therefore pushing it to turn a wheel

EXTERNAL VS INTERNAL CONT.

Internal- powered by controlled explosions Multiple cylinders turn a crank shaft to produce rotary

force that turns the wheel

BASICS OF INTERNAL COMBUSTION ENGINE Gas and oxygen are pumped into cylinder as piston goes

down Gas and oxygen are compressed as piston moves up Spark plug ignites, creating explosion and pushing piston

down Exhaust is pumped out as piston goes back up

Four stroke engine

BASICS CONTINUED

Why four strokes? Why not just one cylinder?

HOW IS A TWO STROKE DIFFERENT? Both input and output valves are open at the same time Less efficient, unused gas is let out Lightweight Less parts

PARTS WORKING IN UNISON

Timing belt allows everything to work in unison

CARBURETOR VS FUEL INJECTION

Carburetor in older model cars. Puts fuel into engine by creating pressure differences. mechanical

CARBURETOR VS FUEL INJECTION CONTINUED Modern way of getting fuel into engine More efficient Electronically controlled

OCTANE RATING

Measurement of “knockback resistance” When compression of piston happens, temperature

increases, and can possibly cause premature explosion. This is how diesel engines work (minus the premature

part). Messes up piston cycle. Higher octane means greater tolerance for higher

temperature via higher pressure