I've repaired and worked on small engines a very, very long time. You will learn alot if you read and gain knowledge from my blogs.
GASOLINE is a hydrocarbon fuel which is a mixture of hydrogen and carbon, which is refined from petroleum. PETROLEUM is a dark, thick liquid that is extracted from our earth by oil wells we see popping up everywhere. Lucky for all of us, petroleum is the second most plentiful liquid in the world; only water is available in greater quantity. Gasoline, however, cannot be recycled as water can. Therefore, it is imperative that we all conserve gasoline and use it wisely, especially today when gas prices are so high. After studing what I do, I can tell you that gasoline contains a great amount of energy. For engine use, it should:
* Ignite readily, burn cleanly, and resist detonation which is a violent explosion.
* It should vaporize easily, without being subject to vapor lock, which means, vaporizing in fuel lines, impeding flow of liquid fuel to your carburetor.
* It should always be free of dirt, water, and abrasives.
Gasoline is assigned an OCTANE NUMBER that corresponds to its ability to resist detonation. Preminum grade gasoline burns slower than regular gasoline. It has a high octane number and is used in engines with high compression. Regular grade gasoline has a lower octane number and burns relatively fast. Generally, regular gasoline is used in small, low compression, one-cylinder and two-cylinder, gasoline engines. We all know that gasoline was once available in both leaded and unleaded varieties. The use of lead compounds was the most economical way to increase gasoline's octane number. For many years, most gasolines contained TETRAETHYL LEAD.
Since way back in the 70's unleaded gasoline has replaced leaded gasoline. Instead of lead compounds, OXYGENATES which is alohols and ethers, are commonly added to these fuels to increase octane levels. The main reason that unleaded gas was introduced was to provide fuel for automobiles equipped with catalytic converters. These vehicles will not operate properly on leaded fuel.
Showing posts with label small engine repair. Show all posts
Showing posts with label small engine repair. Show all posts
Thursday, September 10, 2009
Small Engine Construction and Principles of Operation - Part I
After reading this, you will be able to:
* Explain simple engine operation.
* Know the qualities of gasoline that make you're mower an efficient small engine.
* Know why gasoline is atomized in the small engine.
* Know the basic components of your small engine and know the function of each part.
GASOLINE ENGINES
A gosoline-fueled ingine is a mechanism desinged to transform the chemical energy of burning fuel into mechanical energy. In operation, it controls and applies this energy to mow lawns, cut trees, propel tractors, and perform many other laborsaving jobs. A gasoline engine is an internal combustion engine. Gasoline is combined with air and burned inside the engine. In its simplest form, an engine consists of a ported cyliner, piston, connecting rod, and crankshaft.
The piston is a close fit inside the cylinder, yet it is free to slide on the lubricated walls. One end of the connecting rod is attached to the poston; the other end is fastened to an offset crankpin, or jouranl, of the crankshaft. As the piston moves up and down, the connecting rod forces the journal to follow a circular path, rotating the crankshaft.
SIMPLE ENGINE IN OPERATION
When the engine is cranked, gasoline is atomized (reduced to minute particles) and mixed with air. This mixture is forced through an intake port and into the cylinder, where it is compressed by the piston on the upstroke and ignited by an electrical spark. Combuston forces the piston down to rotate crankshaft. Burning rapidly, the heated gases trapped within the cylinder (combustion chamber) expand and apply pressure to the walls of the cylinder and to the top of the piston. This pressure drives the piston downward on the power stroke, causing the crankshaft to turn. As the piston and connecting rod push the crankshaft journal to the bottom of the stroke, the pressure of the burned gases is released through an exhaust port. Meanwhile, a fresh air-fuel charge enters the cylinder and the momentum of the power stroke turns the crankshaft journal through bottom dead center (BCD) and into the upstroke on another power cycle. Tommorow: Gasoline - The Hydrocaarbon Fuel in Small Engines.
* Explain simple engine operation.
* Know the qualities of gasoline that make you're mower an efficient small engine.
* Know why gasoline is atomized in the small engine.
* Know the basic components of your small engine and know the function of each part.
GASOLINE ENGINES
A gosoline-fueled ingine is a mechanism desinged to transform the chemical energy of burning fuel into mechanical energy. In operation, it controls and applies this energy to mow lawns, cut trees, propel tractors, and perform many other laborsaving jobs. A gasoline engine is an internal combustion engine. Gasoline is combined with air and burned inside the engine. In its simplest form, an engine consists of a ported cyliner, piston, connecting rod, and crankshaft.
The piston is a close fit inside the cylinder, yet it is free to slide on the lubricated walls. One end of the connecting rod is attached to the poston; the other end is fastened to an offset crankpin, or jouranl, of the crankshaft. As the piston moves up and down, the connecting rod forces the journal to follow a circular path, rotating the crankshaft.
SIMPLE ENGINE IN OPERATION
When the engine is cranked, gasoline is atomized (reduced to minute particles) and mixed with air. This mixture is forced through an intake port and into the cylinder, where it is compressed by the piston on the upstroke and ignited by an electrical spark. Combuston forces the piston down to rotate crankshaft. Burning rapidly, the heated gases trapped within the cylinder (combustion chamber) expand and apply pressure to the walls of the cylinder and to the top of the piston. This pressure drives the piston downward on the power stroke, causing the crankshaft to turn. As the piston and connecting rod push the crankshaft journal to the bottom of the stroke, the pressure of the burned gases is released through an exhaust port. Meanwhile, a fresh air-fuel charge enters the cylinder and the momentum of the power stroke turns the crankshaft journal through bottom dead center (BCD) and into the upstroke on another power cycle. Tommorow: Gasoline - The Hydrocaarbon Fuel in Small Engines.
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