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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.
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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.
Blow-by Degreaser Dry-filter type air cleaners Horizontal crankshaft engine Oiled-filter type air cleaners Service intervals Vertical Crankshaft engine Terms
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 engines • By 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
Number of power strokes • Four stroke cycle engines – intake, compression, power, exhaust • Two-stroke cycle engines – compression & intake, power & exhaust
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
Lubricating small engines • Engine oil is vital to engine life • Blow-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
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.
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?