2. 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

3. 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, snow- mobiles, 4-wheelers, mo-peds

4. History 1680 was the first small engine External Combustion Engine- it 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

5. History Internal Combustion Engine – Burned fuel inside the engine. Adv More efficient, power, reduced size & weight Ex. Cars, lawnmowers

6. 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

7. Commonality of Small Engines All engines have these things in common. 1.Intake Stroke 2.Compression Stroke 3.Power Stroke 4. Exhaust Stroke How a 2 stroke functions 2 Stroke Engines  2 cycle combined  2 cyles combined

8. Stroke Paper Define Stroke TDC BDC Operation of a 4 stroke Engine

9. The Engine Consist of 5 Basic Parts All engines have these parts 1. Block 2. Piston 3. Cylinder 4. Crankshaft 5. Camshaft

10. Small Engines are Broken up into 5 Different Groups 1. # of Strokes 2. Ignition 3. Shaft Orientation 4. Cooling System 5. Cylinder Design

11. Ignition Systems A. Pull Start B. Electronic C. Combination

12. 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

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

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