• Using Small Engines

Next Generation Science/Common Core Standards Addressed!

CCSS.ELA Literacy.RST.9‐10.1 Cite specific textual evidence to support analysis of science and technical texts, attending to the precise details of explanations or descriptions.

CCSS.ELA Literacy.RST.9‐ 10.3 Follow precisely a complex multistep procedure when carrying out experiments, taking measurements, or performing technical tasks, attending to special cases or exceptions defined in the text.

CCSS.ELA Literacy. RST.11‐12.2 Determine the central ideas or conclusions of a text; summarize complex concepts, processes, or information presented in a text by paraphrasing them in simpler but still accurate terms.

CCSS.ELA Literacy.RST.11‐12.3 Follow precisely a complex multistep procedure when carrying out experiments, taking measurements, or performing technical tasks; analyze the specific results based on explanations in the text.

Agriculture, Food and Natural Resource Standards Addressed!

PST.02.01. Perform preventative maintenance and scheduled service to maintain equipment, machinery and power units used in AFNR settings.

PST.02.01.01.b. Develop a preventative maintenance schedule for equipment, machinery and power units used in AFNR power, structural and technical systems.

Bell Work / Student Learning Objectives

Identify the reasons why small engines are widely used.

Describe how small engines can be classified.

Identify common service jobs performed on small engines.

Terms

Blow-by

Degreaser

Dry-filter type air cleaners

Horizontal crankshaft engine

Oiled-filter type air cleaners

Service intervals

Vertical Crankshaft engine

Interest Approach

How could we accomplish lawn tasks without small engines?

Small engines

Implements with less than 25 horsepower.

Several million are now in use in the U.S., both two and four cycle

Accomplish tasks that other equipment cannot do. New items are continually being developed.

Small engine popularity

Compact

Lightweight

Easy to service and repair

Affordable

Reasons for small engine trouble

Dirt and dust leads to rapid wear if not serviced properly.

Abuse by overloading.

Do not receive proper service or regular maintenance.

Small engines usually operate at top speed continuously. That would be comparable to you car traveling at 85 mph continuously.

Classifying small enginesBy the position of their crankshafts

By the number of power strokes per crankshaft revolution

Position of crankshafts

Vertical crankshaft engine – its cylinder is in a horizontal position

Horizontal crankshaft engine – may have its cylinder in a vertical, horizontal, or intermediate position

Multi-position crankshaft engine – operates in any position

CrankshaftPositions

Number of power strokes

Four stroke cycle engines – intake, compression, power, exhaust

Two-stroke cycle engines – compression & intake, power & exhaust

Extremeanglesof operationand oilsupply

Common service jobs

Cleaning the engine

Inspect and clean the exhaust system Degreaser – solvent good for cleaning hard to reach places

Inspect cooling system for obstructions

Servicing carburetor air cleaners

Oil-filter type air cleaner – made of a sponge-like filtering material called polyurethane

Dry-filter type air cleaner – consists of a porous filtering material made of paper or fiber

Types ofair cleaners

Lubricating small engines

Engine oil is vital to engine lifeBlow-by – gases under pressure that leak by the piston rings during combustion and the power stroke

Four cylinder engines are lubricated from an oil reservoir

Two-cycle engines are lubricated by specific types of oil mixed in the fuel

Lubrication Systems.

Servicing spark plugs

Anything that inhibits the flow of current through the spark plug and across the spark plug gap will affect the operation of the engine.

Sparkplugoperation

Review/Summary

Why are small engines so widely used?

How are small engines classified?

What are some of the common service jobs performed on small engines?

The End!