Transcript Fundamentals of Small Gas Engines

Fundamentals of Small Gas Engines
Objectives:
-Discuss the uses of small engines
-Observe all safety precautions when working with small engines
-Distinguish between two and four cycle engines
- explain how a 4 cycle engine operates
-Explain how a 2 cycle engine operates
-Identify all the systems in a small engine
-Explain how the different systems of a small engine work
Terms to know
 Internal combustion engine
 External combustion
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engine
Four cycle engine
Piston
Cylinder
Crankshaft
Block
Valves
Intake stroke
 Compression stroke
 Power stroke
 Exhaust stroke
 Flywheel
 Two-cycle engine
 Piston rings
 Carburator
 Venturi
 Camshaft
 Governor
 Magneto
 Primary circuit
 Secondary circuit
Safety precautions
 Wear safety glasses and leather shoes
 Keep your hands, feet and other body parts from all moving
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parts.
Do not allow burning material near oil, solvents or gasoline
Do not smoke near openings of gasoline tanks or containers
Disconnect spark plug cable prior to making any adjustments
on machines to prevent the possibility of accidental engine
start up.
Stop the engine and allow it to cool before refueling
Handle gasoline outdoors whenever possible
Safety precautions
 Never disengage any of the safety equipment or devices on
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the engine or machine
Keep all shields in place
Do not operate engines or force equipment beyond the
designed capacity
Never start and run an engine inside a building where the
ventilation is inadequate.
Never use gasoline as a solvent or to clean engine parts
Dispose of gasoline properly, by pouring it into an approved
container. Never pour in onto the ground or down a drain.
Types of combustion engines
 http://www.animatedengines.com/otto.shtml
How does a 4 stroke engine work?
 http://auto.howstuffworks.com/engine1.htm
 http://www.5min.com/Video/Starting-an-Internal-
Combustion-Engine-145338934
2 stroke engine
How do 2 stroke engines work?
 http://science.howstuffworks.com/transport/engines-
equipment/two-stroke2.htm
 http://videos.howstuffworks.com/howstuffworks/200how-diesel-two-stroke-engines-work-video.htm
Engine Systems
 Compression system
 Fuel system
 Ignition system
 Cooling system
 Lubrication system
 ACTIVITY! Break yourselves into groups of 2-3
 Each group is responsible for 1 system in the engine.You need to
either make a descriptive poster or power point describing your
engine system.YOUR group will be RESPONSIBLE for
TEACHING other groups about your SYSTEM.
QUIZ!
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What is the purpose of oil in the engine?
What is the governor?
What is the difference between a 2 stroke and 4 stroke
engine?
What are some common causes of compression loss?
What connects the piston to the crankshaft?
What are piston rings needed for?