Internal Combustion Engine
• Internal combustion engines are most commonly used for mobile propulsion in vehicles and portable machinery. In mobile equipment, internal combustion isadvantageous since it can provide high power-to-weight ratios together with excellent fuel energy density. Generally using fossil fuel(mainly petroleum), these engines have appeared in transport inalmost all vehicles (automobiles, trucks, motorcycles, boats, and in a wide variety of aircraft and locomotives).
Operation - Four-stroke cycle (or Otto cycle)
As their name implies, operation offour stroke internal combustion engines have four basic steps that repeat with every two revolutions of the engine: 1. Admission 2. Compression Stroke 3. Explosion 4. Escape of waste
1. Admission:• The first stroke of the IC engine is also known as the suction stroke because the piston moves to the maximum volume position (downward direction in the cylinder). The inlet valve opens as a resultof piston movement, and the vaporized fuel mixture enters the combustion chamber. The inlet valve closes at the end of this stroke.
2. Compression stroke:
• In this stroke, both valves areclosed and the piston starts its movement to the minimum volume position (upward direction in the cylinder) and compress the fuel mixture. During the compression process, pressure, temperature and thedensity of the fuel mixture increases.
• When the piston reaches the minimum volume position, the spark plug ignites the fuel mixture and burns. The fuel produces power that istransmitted to the crank shaft mechanism.
4. Escape of waste:
• In the end of the power stroke, the exhaust valve opens. During this stroke, the piston starts its movement in the minimum volume position.The open exhaust valve allows the exhaust gases to escape the cylinder. At the end of this stroke, the exhaust valve closes, the inlet valve opens, and the sequence repeats in the next cycle. Four...
Leer documento completo
Regístrate para leer el documento completo.