played gasoline engine piston reaches the compression top dead center, during which time the crank angle turned referred ignition timing from the ignition advance angle.
1. Noun interpretation of the ignition advance angle
played gasoline engine piston reaches the compression top dead center from the ignition timing, during which time the crank angle turned called spark advance angle.
igniting the mixed gas from the combustion to burn a time course, the optimum ignition advance angle role in various conditions is the gas expansion work of the piston in the maximum segment trend downward stroke. In this way the maximum efficiency, minimum vibration, low temperature rise.
impact spark advance biggest factor is speed. As the speed increases, the angle rotated the same time becomes short, only a larger lead angle to give the corresponding time advance.
In theory the minimum ignition advance angle is 0 degrees, but only in order to prevent ignition of air-fuel mixture during the power stroke (which could cause loss of power) tends to 5 degrees or more, which is starting angular rotational speed required. The maximum ignition timing can not be too large, generally can not exceed 60 degrees, otherwise the problem will highlight the vibration and temperature rise, efficiencyIt will also decline. Crankshaft speed is actually limited.
2. Detailed optimum ignition advance angle
premature ignition, knocking will cause the piston up blocked, reduced efficiency, heat load, mechanical load, vibration, and increased noise, which is to be prevented. Late ignition, a gas difficult to work, high fuel consumption, low efficiency and large exhaust sound. Regardless of ignition too early or too late, it will affect the efficiency of the engine. In addition to engine speed, optimum ignition angle is also affected by many other factors:
● higher cylinder temperature and cylinder pressure, the faster the combustion of the air-fuel mixture, the ignition advance angle will be smaller. Factors Affecting the cylinder temperature and cylinder pressure of an engine compression ratio, temperature, cylinder temperature, load and the like.
● octane number of gasoline, i.e. gasoline label, which is the stronger the higher the numeral gasoline anti-knocking ability, more appropriate to allow the ignition advance angle.
● gas mixing ratio, the lean air-fuel mixture is too thick, combustion speed slower than the need to increase the ignition advance angle, and mainly depends on the gas mixing ratio of the throttle opening degree, altitude.
are fitted on the automobile engine knock sensor, when detecting the occurrence of knocking, the engine computer controls the ignition system to reduce the ignition advance angle. To accomplish relatively complex, precise modulation, by conventional mechanical ignition is difficult to accomplish. Only computer ignition, to high-speed, accurate, consistent optimum ignition timing.
3. How to check and adjust the ignition timing
● inspection, adjustment platinum contact
Check whether there is platinum contact scuffs, if traces of sand bars or application 0 No traces of sandpaper to gently wipe. Since the contact surface of the platinum contact only a thin layer of carbide, if Over time, the cemented carbide is worn away, the contact time to be replaced, the contact surface of the contact percentage of not less than 80. Platinum contact gap is generally 0.4 ~ 0.5mm.
● inspection, the ignition advance angle
is removed from the vacuum compensation in advance on the sub-chamber vacuum hose means, and plug the hose is connected to two ports, the engine idling, At this timing when the lamp ignition check ignition advance angle. For TJ376Q engine and TJ370Q engine, the ignition advance angle is 5 ° + 2 ° (850 + 50f / min); For JL368Q engine, the ignition advance angle of 7 ° (900r / min); CFGFda462Qv motive, which spark advance of 10 ° + 1 ° (900r / min); 276Q for the engine, the ignition advance angle of 6 ° + 2 ° (900r / min).
The method can be used to switch the distributor housing to the ignition advance angle. When the counterclockwise rotation of the distributor housing, the ignition advance angle increases; when rotated clockwise distributor housing, the ignition advance angle will be reduced.
● ignition timing verification
starting the engine, repeatedly pressed the accelerator, if the engine was strong, and there is no abnormality percussion, it indicates the ignition advance angle suitable. Timing light can also be used to confirm that the ignition advance angle: With increasing engine speed, the timing marks toward the ignition advance angleIncreasing the movement direction.