Docstoc

Small Engines

Document Sample
Small Engines Powered By Docstoc
					SMALL ENGINES


     ENGINE
    OPERATION FOR
    A FOUR STROKE
    ENGINE
SMALL ENGINES

     An engine is a device which
converts energy into mechanical
motion to do work.

     Small engines are described as
internal combustion engines rated up to
25 horsepower.

     A small engine has either a
spark ignition or a compression ignition
based on how the fuel is ignited.


      Small engines are classified as either
four-stroke cycle engines or two-stroke
cycle engines.
PARTS OF THE ENGINE


         CYLINDER BLOCK
             Engine component which
             consists of the cylinder bore,
             cooling fins, and valve train
             components. Made of cast
         CYLINDER HEAD
             aluminum alloy that are
              Engine component made out of
             lightweight and dissipate heat
              cast aluminum alloy fastened
             rapidly.
              to the FINS
         COOLINGend of the cylinder block
               An integral thin crankshaft.
              farthest from the cast strip
               designed to provide efficient
         HEAD GASKET
               air circulation and
                A filler material placed
               dissipation of heat away from
                between the cylinder block
               the engine cylinder block
                and cylinder head
          SPARK the air stream. to seal
               into PLUG
                the combustion chamber.
                 Component that isolates
                Made of soft metals and
                 the electricity and
                graphite layered together.
                 produces the spark for the
                 engine
PARTS OF THE ENGINE

PISTON
     A cylindrical engine component
     that slides back and forth in the
     cylinder ROD
CONNECTING bore by forces produced
     during the combustion process.
     Engine component that
     transfers motion from the
CRANKSHAFT the crankshaft and
     piston to
     functions as a lever arm.
      An engine component that
      converts linear (reciprocating)
      motion
FLYWHEEL of the piston into rotary
      motion.
       A cast iron disk that is
       mounted at one end of the
       crankshaft to
COUNTERWEIGHTS provide inertia
        A the engine.
       forprotruding mass cast into the
        crankshaft which partially
        balances the forces of a
        reciprocating piston.
PARTS OF THE ENGINE

                    PISTON
PISTON: A cylindrical engine component that
        slides back and forth in the cylinder
        bore by forces produced during the
        combustion process.
PARTS OF THE ENGINE

                PISTON
PISTON:

          DIFFERENT PISTON TYPES:



   FLAT      DOMED   IRREGULAR   DISHED
PARTS OF THE ENGINE

                       PISTON
PISTON RINGS:
                 An expandable split ring used to provide a
                 seal between the piston and the cylinder
                 wall
  Three types:
                  1.   COMPRESSION RING

                  2.   WIPER RING
                  3.   OIL RING




                                    1
                                    2
                                    3
PARTS OF THE ENGINE
 VALVE TRAIN
VALVE HEAD

MARGIN

VALVE FACE

VALVE SEAT

VALVE NECK

VALVE GUIDE

VALVE SPRING

VALVE ROTATOR

VALVE SPRING RETAINER
FOUR STROKE CYCLE ENGINE



  INTAKE STROKE
 COMPRESSION STROKE
  POWER STROKE
  EXHAUST STROKE
      INTAKE STROKE

 Occurs from TDC to BDC

 Intake valve opens


 Air-Fuel that was previously
mixed in the carburetor is now
sucked into the combustion
chamber due to the low pressure
created inside.
     COMPRESSION
       STROKE
 Compresses the Air-Fuel
mixture


By compressing the Air-Fuel
mixture:

    Allows for more energy to
    be released.
    Increases fuel
    vaporization
    Allows for more complete
    burning
               POWER
               STROKE
 Spark occurs igniting
compressed air-fuel mixture
       Spark occurs 20 degrees before
      TDC so the flame front can
      spread throughout combustion
      chamber

Gases ignite pushing piston
away from the cylinder head

Linear motion from the
piston is transferred into a
rotary motion on the
crankshaft
           EXHAUST
            STROKE
 Exhaust valve opens

 Inertia from the flywheel
and other parts push the
piston back up toward TDC,
pushing the spent gases out of
the combustion chamber.
THE END

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:7
posted:8/4/2011
language:English
pages:14