Introduction to small engines
Learning some Basics
In this course we are taught that a small engine is defined as an engine producing less than 25HP (Horse Power)
Uses for small engine vary widely, But are broken into two main categories. "Residential and Recreational." These are engines used by home owner, or engines used to recreation activities. "Commercial & Industrial" is the other catagory. These are engines used on the work site.
Residential and Recreational Small Engines
-Lawn Mowers ( Push mowers and self propelled)
-Lawn Tractors and Garden Tractors.
-Leaf Blower
-Garden Tiller
-Hedge Trimmer
-Lawn Sweeper
-Chain Saw
-Log Splitter
-Wood Chipper
-Snow Thrower
-Pressure Washer
-Outboard Engine (Boat Engine)
-Go-Cart
Commercial & Industrial Small Engines
-Generator
-Welders (Feature a generator for Electricity)
-Air Compressor
-Road Line Sprayer
-Commercial Paint Sprayer
-Pressure Washer
-Cement Mixer
-Circular Saw
-Water pump / Sump Pump
Uses for small engine vary widely, But are broken into two main categories. "Residential and Recreational." These are engines used by home owner, or engines used to recreation activities. "Commercial & Industrial" is the other catagory. These are engines used on the work site.
Residential and Recreational Small Engines
-Lawn Mowers ( Push mowers and self propelled)
-Lawn Tractors and Garden Tractors.
-Leaf Blower
-Garden Tiller
-Hedge Trimmer
-Lawn Sweeper
-Chain Saw
-Log Splitter
-Wood Chipper
-Snow Thrower
-Pressure Washer
-Outboard Engine (Boat Engine)
-Go-Cart
Commercial & Industrial Small Engines
-Generator
-Welders (Feature a generator for Electricity)
-Air Compressor
-Road Line Sprayer
-Commercial Paint Sprayer
-Pressure Washer
-Cement Mixer
-Circular Saw
-Water pump / Sump Pump
Commercial & Industrial Small Engines
-Generator
-Welders (Feature a generator for Electricity)
-Air Compressor
-Road Line Sprayer
-Commercial Paint Sprayer
-Pressure Washer
-Cement Mixer
-Circular Saw
-Water pump / Sump Pump
-Generator
-Welders (Feature a generator for Electricity)
-Air Compressor
-Road Line Sprayer
-Commercial Paint Sprayer
-Pressure Washer
-Cement Mixer
-Circular Saw
-Water pump / Sump Pump
Four Stages of Engine operation
Engines operate via 4 simple stages (or strokes)
Intake - Air is mixed with fuel, and drawn into the cylinder
Compression - Piston compresses are + fuel mixture in combustion chamber
Power - Fuel mixture is ignited. A contained explosion pushes the piston down
Exhaust - Exhaust gases are released from the cylinder. The stages then repeat.
Top Dead Center (TDC) - Piston is at its highest position in cylinder
Bottom Dead Center (BDC) - Piston is at its lowest position in the cylinder
Combustion Chamber - Small space above Piston (at TDC) where fuel mixture is compressed and ignited.
Intake - Air is mixed with fuel, and drawn into the cylinder
Compression - Piston compresses are + fuel mixture in combustion chamber
Power - Fuel mixture is ignited. A contained explosion pushes the piston down
Exhaust - Exhaust gases are released from the cylinder. The stages then repeat.
Top Dead Center (TDC) - Piston is at its highest position in cylinder
Bottom Dead Center (BDC) - Piston is at its lowest position in the cylinder
Combustion Chamber - Small space above Piston (at TDC) where fuel mixture is compressed and ignited.
How Engine are rated
Engines are rated in one of two ways;
- The amount of power it produces
- The size (displacement) of the engine
Work - A force that is applied over a specified distance.
Work = DISTANCE X FORCE (ft x lbs or ftlbs)
Power - The amount of work that can be performed over time.
Power = WORK/TIME (ft-lbs/seconds) = FPS (feet per second)
Engines are most commonly rated by HorsePower (HP) Horse power measures the amount of work a typical horse could perform.
- 1 Horsepower = 550 Feet Per Second (FPS)
Dynamometer - A device for measuring force, torque, or power. A Known load is applied to output shaft of engine (Usually hydraulic, or electric.)
Brake HorsePower - The Maximum power output of an engine
Rated HorsePower - 80% of maximum power output. (an engine with 10 brake horsepower would be rated at 8 HP)
Torque - A measure of twisting or rotational force. (ft-lbs) An engine produces its maximum torque at a lower rpm than its peak HP and declines slightly as RPM increases.
- The amount of power it produces
- The size (displacement) of the engine
Work - A force that is applied over a specified distance.
Work = DISTANCE X FORCE (ft x lbs or ftlbs)
Power - The amount of work that can be performed over time.
Power = WORK/TIME (ft-lbs/seconds) = FPS (feet per second)
Engines are most commonly rated by HorsePower (HP) Horse power measures the amount of work a typical horse could perform.
- 1 Horsepower = 550 Feet Per Second (FPS)
Dynamometer - A device for measuring force, torque, or power. A Known load is applied to output shaft of engine (Usually hydraulic, or electric.)
Brake HorsePower - The Maximum power output of an engine
Rated HorsePower - 80% of maximum power output. (an engine with 10 brake horsepower would be rated at 8 HP)
Torque - A measure of twisting or rotational force. (ft-lbs) An engine produces its maximum torque at a lower rpm than its peak HP and declines slightly as RPM increases.
Engine Displacement - The volume of space that the piston moves from the very bottom of its stroke to the very top of its. (BDC - TDC)
Displacement = PI(D^2)(S)(N) / 4
PI = 3.14
D = Diameter of Cylinder
S = Stroke
N = Number of Cylinders
Stroke - The Distance the piston travels from BDC -> TDC
Compression Ratio - Ratio of largest cylinder volume to smallest cylinder volume. (BDC -> TDC) Most small engine are 5:1 - 6:1
Displacement = PI(D^2)(S)(N) / 4
PI = 3.14
D = Diameter of Cylinder
S = Stroke
N = Number of Cylinders
Stroke - The Distance the piston travels from BDC -> TDC
Compression Ratio - Ratio of largest cylinder volume to smallest cylinder volume. (BDC -> TDC) Most small engine are 5:1 - 6:1
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