Transcript Small Engine

Objectives
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Define a small engine
Uses of a small engine
History of the small engine
Types of small engines
Commonality of small engines
Basic Parts
Different groups of small engines
I.
Small Engine –
an engine that produces power by
burning a fuel into a mechanical force
that is rated under 25hp
II. Equipment used
- lawn mowers, weed eaters, snowmobiles, 4-wheelers, mo-peds
History
• 1680 was the first small
engine
• External Combustion
Engineit derives heat from the
combustion of water into
steam that in turns
powered the pistons inside
the engine.
Ex. Steam engines
What are some problems with this
engine?
Large, not as efficient, very heavy
History
• Internal Combustion
Engine –
Burned fuel inside the
engine.
Adv
More efficient, power,
reduced size & weight
Ex. Cars, lawnmowers
Types of Small Engines
A.) 2 stroke (cycle) engine
- operates on a series of 2 strokes to
complete a cycle
B.) 4 stroke (cycle) engine
- operates on a series of 4 strokes to
complete its cycle
Commonality of Small Engines
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All engines have these How a 2 stroke functions
things in common.
• 2 Stroke Engines
1. Intake Stroke
 2 cycle combined
2. Compression Stroke
3. Power Stroke
 2 cyles combined
4. Exhaust Stroke
Stroke Paper
• Define Stroke
• TDC
• BDC
• Operation of a 4 stroke Engine
The Engine Consist of 5 Basic Parts
 All engines have these parts
1. Block
2. Piston
3. Cylinder
4. Crankshaft
5. Camshaft
Small Engines are Broken up
into 5 Different Groups
1. # of Strokes
2. Ignition
3. Shaft Orientation
4. Cooling System
5. Cylinder Design
Ignition Systems
A. Pull Start
B. Electronic
C. Combination
Shaft Orientation
What is this??
- The axis of the CRANKSHAFT
Two Options
1.
Vertical
2.
Horizontal
Selected for efficiency in driving components
Ex. Push lawn mower – Vertical
Snow blowers – Horizontal
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Cylinder Design
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What way can cylinders come?
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Automobiles are multi-cylinders and are
called V-6 or V-8
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Why do we use the V option for cars/trucks
More Power than horizontal or vertical
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Cooling Systems
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How is an engine cooled?
1. Air – air fins
2. Water – radiator