Gasoline Generator working principle(b)
Post Time: 2016-08-17
. [1]
Compression stroke
Is sucked into the cylinder so that combustible mixture can burn rapidly to produce greater pressure, so that the engine made
A greater power must, before burning the combustible mixture compressed to reduce the volume and density increase, temperature
Elevated, that requires the compression process. In this process, the intake and exhaust valve fully closed, push the crankshaft
From the dead center of the piston bottom dead center to move up an itinerary that compression stroke. At this point the mixture will be increased pressure
0.6-1.2MPa, temperatures up to 600-700K.
There is a very important concept in this stroke is the compression ratio. The so-called compression ratio, that is, before compression cylinder
Minimum volume ratio of the maximum volume of gas and compressed. Usually the greater the compression ratio, the compression end when
Pressure and temperature of the mixed gas will be higher, the
combustion speed more quickly, and thus the greater the power of the
engine issue,
Economy better. General car compression ratio between 8-10, but now the latest listing of Polo reached
The high compression ratio of 10.5, so it's torque performance is relatively good. However, the compression ratio is too large, not only
Combustion can be further improved, but there will be flash fire and surface ignition and other abnormal combustion phenomenon.
Deflagration due to gas pressure and high temperature in the
combustion chamber to ignite from the center than the far end of the
combustible mix
Aiki one kind of spontaneous combustion caused by abnormal combustion. Deflagration flame spread outward at very high rates, even
In the case of the expansion of the gas too late, sharp rise in
temperature and pressure, a pressure wave to the forward speed of sound
Advance. When this pressure wave hit the wall of the combustion chamber is on a sharp knocking sound. At the same time, it can also cause hair
Motivation overheating, power down, fuel consumption increases and a series of adverse consequences. Serious deflagration will be even
Resulting in valve burning, bush broken spark plug insulators by mechanical damage and breakdown phenomena.
In addition to flash fire, high compression ratio of the engine may also face another problem: the surface ignition. This is
On the hot surface of the cylinder at the hot (such as an exhaust
valve head, spark plug electrodes, carbon deposition at) ignite the
mixture gas production
Another student abnormal combustion (also known as hot or early ignition combustion). Ignition occurs when the surface is also accompanied
Strong Knocking sound (more boring), high pressure will produce an increase in engine load, reduced life. [1]
Expansion stroke
In this process, the intake and exhaust valve remains closed. When the piston approaches top dead center, the spark plug emit electrical fire
Flowers, lit the combustible mixture is compressed. After the combustible mixture is burned off a lot of heat, this time
The gas pressure and temperature increase rapidly. The maximum pressure which can reach up to 3-5MPa, the corresponding temperature
And up to 2200-2800K. High temperature and high pressure gas pushes the piston downward by the TDC TDC motion by even
The crank lever to rotate and output mechanical energy, in addition to
maintaining the engine itself continues to run, the rest was used for
Outside acting. During movement of the piston, the cylinder internal volume increases, gas pressure and temperature are decreased rapidly
, At the end of this stroke, the pressure was reduced 0.3-0.5MPa, the temperature was 1300-1600K. [1]
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