Objectives Define a small engine Uses of a

Objectives • • 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 25 hp 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 • All engines have these How a 2 stroke functions things in common. • 2 Stroke Engines 1. Intake Stroke Ø 2 cycle combined 2. Compression Stroke 3. Power Stroke Ø 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 n 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 l

Cylinder Design l What way can cylinders come? l Automobiles are multi-cylinders and are called V-6 or V-8 l Why do we use the V option for cars/trucks More Power than horizontal or vertical I

Cooling Systems l How is an engine cooled? 1. Air – air fins 2. Water – radiator