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