Agriculture Engineering-chptr 6

1,055 views

Published on

Published in: Technology, Business
0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
1,055
On SlideShare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
121
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

Agriculture Engineering-chptr 6

  1. 1. TWO STROKE ENGINE CYCLE
  2. 2. Two Stroke Engine• Used to provides power for small machines for farms or in horticultural work• Examples of 2 stroke engine are hand operated hedge trimmers, hand operated chain saws, small rotary cultivators, grass cutters and horticultural sprayers• Valves are not normally fitted in 2 stroke engine, instead opening known as ports are arranged in the walls of the cylinder
  3. 3. • Inlet port – where the carburetor is attached and fuel/air enters the crankcase• Transfer port – where compressed fuel/air is transferred from crankcase to combustion chamber, ready for compression stroke• Exhaust port – at the end of power stroke the piston uncovers the exhaust port and spend gasses escape
  4. 4. The Intake Stroke The piston moves down, inlet port closed and induction port opened• This downward movement of the piston creates a partial vacuum and air rushes through the transmission port into the cylinder
  5. 5. The Compression Stroke• The piston moves up, 2 events is involved;• Induction port and exhaust port closed on compression of a previous charge, a partial vacuum is created in the sealed crankcase• The piston uncovers the inlet port and air rushes through the carburetor taking fuel/air mixture with it into the crankcase
  6. 6. The Power StrokeWhen the piston is in Top Dead Centre, thespark plug sets fire to the mixture which burnsand expand, and in doing so forces down thepiston
  7. 7. The Exhaust StrokeThe piston moves down again, 2 events involved;• The exhaust port open so that the spent gasses escaped• The inlet port closed and induction port opened on compression the fuel/air mixture into the cylinder
  8. 8. Engine Governor• The governor is a device which automatically controls the speed of the engine under varying load.
  9. 9. Function1) Maintain a selected speed2) Limit the slow and fast speed3) Shut down the engine when it over speeds
  10. 10. • Governor on the engine automatically regulates speed at whatever setting you select on the speed control (throttle lever)• If engine machine is operated much faster than the top speed specified, wear increases rapidly• If operated much slower, less power is available and operating costs increases
  11. 11. Operation of GovernorAfter you set the speed control lever, the job ofthe governor is to adjust the amount of fuel-airmixture so that the engine speed remains thesame even though the load variesThe governor must be sensitive to speed changesThe governor is mounted on the engine camshaftwhere it is directly affected by any slight inchange in engine speed
  12. 12. THANK YOU

×