Motors quad and two – stroke
Four- and two-stroke engines
| Four stroke engine | two-stroke engine | |
| Advantages | – Higher operating life – Higher operating efficiency, lower fuel consumption – Less air pollution – Less noise – Maximum power distributed over a wide range of crankshafts – Lower maintenance rate | – Higher power than the four-wheel drive, which has the same capacity and at the same rotational speed (assuming twice the power due to ignition occurring once per crankshaft revolution instead of two) – It has a high ratio of weight to power as it is lighter in weight and more capable – Less production cost, And cheaper – It can be operated in any position, as there is no oil container like in the four-wheel drive, which limits its position – Less parts and therefore easier maintenance and lighter weight – Light weight made it used in hand-held equipment (tree trimmer, saw) – Operation Soft as it burns every lap, and needs a smaller flywheel for a four-wheel drive of the same capacity |
| Defects | – More parts – Less power than a twin engine of the same capacity and at the same revving speed, power stroke every two crankshafts – Higher price – Heavier weight | – Faster wear, shorter operating life, due to lack of suitable lubrication system – Needs to add oil to gasoline, increases operating expenses (add oil to fuel in a ratio of 1:16 to 1:24) – More pollution, due to simplicity of design (no valves) Leaks Part of the charge, also burning oil with the charge – Low efficiency, as a result of simple design, leads to higher fuel consumption – High sound and high noise – Low power at slow speeds – Poor filling efficiency, charge escapes and part of the exhaust remains in the cylinder – Hotter, temperature High due to combustion per revolution, and not enough cooling time – maximum power is concentrated in a narrow range of speeds (rpm) and at higher speeds – higher maintenance rate |
* Stroke is the distance the piston travels from its maximum point inside the cylinder (upper dead point) to its lowest point inside the cylinder (lower dead point).
* The internal combustion engine works through a cycle , this cycle consists of four procedures to complete the combustion process (intake, pressure, power, exhaust), and it is repeated after that. A four-stroke engine that completes these procedures in four strokes, and the crankshaft rotates for two turns, is called a four-stroke engine. A two-stroke engine is called when it completes these procedures in two strokes, and the crankshaft rotates one revolution.
Four-stroke engine:
| Round number | the half | piston movement | fuse placement | crankshaft movement | ||
| procedures | intake valve | exhaust valve | ||||
| 1 | Clouds intake | down | Open | Closed | 0 to 180 degrees (1/2 turn) | |
| 2 | Pressure pressure | up | Closed | Closed | 180 to 360 degrees (1/2 turn) | |
| 3 | Ability power | down | Closed | Closed | 360 to 540 degrees (1/2 turn) | |
| 4 | Exhaust exhaust | up | Closed | Open | 540 to 720 degrees (1/2 turn) | |
| number of runs | 4 runs | Number of crankshaft turns | (2 roll) | |||
– the intake valve opens at the end of the exhaust stroke and closes at the beginning of the compression stroke
– the exhaust valve opens at the end of the power stroke and closes at the beginning of the intake stroke
– the spark occurs at the end of the compression stroke (while the piston is rising and before the upper dead point)
Two-stroke engine:
| Round number | the half | piston movement | crankshaft movement | ||
| procedures | |||||
| 1 | Pull and pressure intake & compression | up | 0 to 180 degrees (1/2 turn) | ||
| 2 | The ability of exhaust power ‘s & Exhaust | down | 180 to 360 degrees (1/2 turn) | ||
| number of runs | 2 stroke | Number of crankshaft turns | (1 roll) | ||
– To complete the required four actions in only two strokes, the bottom of the piston (crankcase) is used to do this
– As the piston rises to compress the charge above the surface of the piston, drag occurs (the charge enters the bottom of the piston)
– As the piston goes down in the power stroke, the charge pressure occurs at the bottom piston; At the end of the power stroke, the charge from the bottom of the piston enters the piston to sweep the exhaust.
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