What is engine surge and under what circumstances does it occur?

Engine surge is generally caused by aircraft engines, mainly due to unstable air intake.

Surge is an abnormal operating condition of the engine, caused by the air flow in the compressor and the speed of the compressor deviating too much from the design state. Surge is a fatal failure of the engine, which can lead to engine shutdown in the air or even fatal damage to the engine in severe cases. The index that measures the surge performance of the engine is called "surge margin", that is, the change in the flow rate of the inlet of the engine will cause surge, and this value is generally required to reach 15 or even 20 or more.

The performance of the aviation turbine engine should be advanced and the stable working range should be wide, first of all, the surge margin should be large, and the working point of the compressor should be far away from the surge boundary. Secondly, the engine should have a strong ability to resist distortion. The air inlet is sometimes uneven, especially when the aircraft is maneuvering, the air flow of the inlet lip and mouth is separated, resulting in distortion of the compressor inlet and uneven airflow.

At this time, the surge margin of the engine will be reduced, and the acceleration and deceleration will consume part of the surge margin, which may also cause stopping, so the surge margin must be sufficient and insensitive to distortion. The tail flame of the missile is also easy to cause distortion of the temperature field and stop the engine, so it is necessary to have an automatic control system for launching and preventing asthma.

The low air intake leads to insufficient supply and abnormal combustion of the combustion chamber. It's like when you hold your breath for a long time and then you cough when you inhale.

The engine works at high rpm and low intake pressure.

1. Check whether the ignition system is faulty. Generally, it is caused by the ignition coil or the aging of the spark plug, and the damaged ignition coil or spark plug can be replaced. The inspection of the ignition coil needs to use the computer to read the specific fault code, if the corresponding cylinder has a misfire, it is generally a problem with the ignition coil.

2. There is too much carbon deposition in the engine. In this case, it is recommended to clean the carbon deposits in the engine, especially the carbon deposits in the intake tract and cylinder of the throttle. The carbon deposits in the cylinder are mainly the piston position and the valve base position, and then rematch the throttle.

3. Oil circuit failure. In this regard, it is necessary to check whether the fuel supply pressure of the gasoline pump is normal, and if the oil supply pressure is unstable, it is necessary to replace the new gasoline pump in time.

10 km? That's a new car? I can only seriously suspect that there is a problem with the oil you add, find a bigger gas station and add some high-grade gasoline to mix it, after running this oil, next time you must find a gas station with a good reputation to try, it should be good.

Isn't it almost out of gas? Maybe there's water in the oil,

If you want a new car, it's generally fine, so don't wonder if there's something wrong with the car, it may be an external factor. I'm just skeptical, I don't really understand. o( o haha

Surge is generally for the supercharger, when the engine speed and load are relatively small, and the air intake is less. Since the supercharger compressor works in a certain range of air intake, when it is less than a certain value, surge will occur, and when it is greater than a certain value, blockage will occur; Knocking is for gasoline engines, and when the engine compression ratio is too large, the knocking phenomenon will occur. To put it simply, the mixture is still in the compression process, and when the spark plug has not yet jumped, the high-pressure mixture reaches the auto-ignition temperature and begins to burn violently.

Gasoline engines are more prone to detonation after adding a supercharger.

1. The ignition angle is too advanced:

In order for the piston to gain power as soon as it enters the power stroke after the end of compression top dead center, it is common to ignite the piston before it reaches the top dead center (because it takes some time from ignition to complete combustion). Ignition too early will cause most of the oil and gas to burn when the piston is still compressing the stroke, and the unburned oil and gas will be subjected to great pressure and spontaneous combustion, resulting in detonation.

Second, the engine is overly carbonized

Excessive carbon deposition in the combustion chamber of the engine will not only increase the compression ratio (high pressure), but also produce high temperature hot spots on the surface of the carbon deposit, causing the engine to knock.

3. The engine temperature is too high

If the engine is too hot, the inlet temperature is too high, or the engine cooling water is poorly circulated, which will cause the engine to detonate due to high temperature.

Fourth, the air-fuel ratio is incorrect:

Too thin the fuel-air mixing ratio will increase the combustion temperature, and the increase in combustion temperature will cause the engine temperature to rise, of course, it is easy to knock.

Fifth, the fuel octane number is too low

The octane number is an indicator of the knock resistance of the fuel, and the higher the octane number, the stronger the knock resistance. Engines with high compression ratios have higher pressure in the combustion chamber, and are prone to knocking if fuel with low knock resistance is used.

The cause of engine knocking is ().

a.The compression ratio is too small.

b.The octane rating is too low (just so the answer is confusing).

c.The ignition of filial piety is too early.

d.The engine temperature is too low.

In the case of engine knocking, the pressure in the combustion chamber is abnormal due to abnormal combustion of the engine. The cause of detonation is usually due to the fact that the flame in the combustion chamber has not spread completely. And the oil and gas that was not burned in the distance also burned at this time.

The result is knocking.

Detonation is an abnormal combustion phenomenon in the engine. Detonation occurs in the compression stroke. When the engine is in the compression stroke, the intake and exhaust valves close and the engine's pistons run upwards.

The piston runs upwards to compress the combustible mixture, which increases the temperature and pressure.

Engine knocking is a sudden, long-term continuous vibration of the cylinder due to abnormal ignition. At this time, the owner will obviously feel the abnormal vibration of the engine.

The cause of engine knocking is generally excessive carbon deposition in the combustion chamber of the engine, or the engine temperature is too high.

Detonation, an abnormal working state of the engine, generally refers to the sudden non-long-term continuous vibration of the engine cylinder due to abnormal ignition, the user can clearly feel the abnormal sound and vibration of the engine, and weaken the engine output power, increase the temperature, increase fuel consumption, and cause a certain degree of damage to the engine.

When the engine sucks in the mixture of fuel vapor and air, before the compression stroke reaches the designed ignition position, various factors outside the control cause the gas mixture to ignite and burn on its own, and the huge impact force generated by the combustion will be opposite to the direction of the piston movement, causing the engine to vibrate, which is called detonation.

The general detonation is because after the ignition of oil and gas in the combustion chamber, the flame has not completely spread, and the remote unburned oil and gas spontaneously combust due to high temperature or high pressure, and the flame collides with the regular burning flame and generates great pressure, which makes the engine produce abnormal knocking.

In fact, it is a phenomenon that the pressure and temperature of the engine are too high when combustion, resulting in abnormal compression ignition of the mixture. He was caused by the following reasons. The first combustion chamber has carbon deposits, the second fuel octane number is low, the third is that the ignition advance angle is inaccurate, and the fourth is that the engine temperature is too high.

Fifth, the air-fuel ratio is incorrect.

The high temperature of the engine can cause knocking, because n-heptane in a high-temperature environment will decompose and spontaneously ignite in advance, which will cause disorderly or irregular flame combustion; In addition, carbon deposits will also be partially burned in an abnormally high temperature and high pressure environment, and sparks will naturally cause detonation.

The crisp and discontinuous sound of metal striking in the engine is known as knocking. Since the octane number of gasoline is too low, it will ignite without complete combustion.

That is, the engine vibrates very badly, abnormal noise, and you can feel the constant vibration.

The main reason is: the ignition advance angle is not accurate. The air-fuel ratio is incorrect, and carbon is deposited in the combustion chamber.

In this case, the ignition advance angle can be delayed, and the oil circuit and fuel injector can be cleaned.

The knocking of the engine refers to the presence of certain conditions. The pressure curve fluctuates at high frequency and in large increments. At this point, the speed of the flame changes dramatically from the shape of the flame's front.

The main reason is that the ignition angle is too early. There is also excessive carbon deposition in the engine. As well as the temperature of the engine is too high.

Engine detonation, generally the ignition point of the mixture is too low, to be precise, the ignition point of gasoline can not withstand the high temperature and high pressure environment of the combustion chamber, spontaneous combustion in advance, in fact, the core is mainly related to the temperature of the engine.

Detonation is a phenomenon of abnormal combustion when the engine is running; When the engine burns normally, the spark plug receives the ignition signal of the ECU, and the combustible mixture is ignited, and the flame is from the core of the flame to the combustible mixture close to the spark plug at a speed of 3040ms; It spreads to the surrounding unburned mixture area, so that the mixture in the combustion chamber burns sequentially until it ends.

Under certain conditions (such as a high compression ratio), the combustion of the gasoline engine will become abnormal, the pressure curve will appear high-frequency, large fluctuations, and the DP dt value near the top dead center will fluctuate sharply to (DP dt) max= high, and the flame propagation speed and flame front shape will change sharply.

Generally, there will be a slight discontinuous percussion sound, which is quite crisp. It may be that the point is too advanced. Excessive carbon deposition in the engine, high engine temperature, and a series of other reasons.

Generally, the engine knocks because the flame has not completely spread after the ignition of the oil and gas in the combustion chamber, and the remote unburned oil and gas is natural due to high temperature or high pressure, which makes the engine vibrate abnormally.

The normal propagation speed of the flame is tens of meters per second, and the speed of the detonation flame can reach thousands of meters, which will cause serious vibration of the piston, and the collision with the cylinder wall will cause serious wear and tear and pull the cylinder.

The ignition angle is too advanced, in order to make the piston get power immediately after the end of the compression stroke, it is usually ignited in advance before the piston reaches the top dead center; Ignition too early will cause most of the oil and gas to burn when the piston is still compressing the stroke, and the unburned oil and gas will be subjected to great pressure and spontaneous combustion, resulting in detonation.

When the mixture of gasoline and air enters the cylinder, the piston compresses it. When the temperature and pressure in the cylinder increase, the density and molecular movement speed of the mixture will also increase, and the mixture will burn easier and faster, so as to obtain better power and economy.

Engine knocking, an abnormal working state of the engine, generally refers to the sudden non-long-term continuous vibration of the engine cylinder caused by abnormal ignition, the user can obviously feel the abnormal engine sound and vibration, and weaken the engine output power, increase the temperature, increase fuel consumption, and cause a certain degree of damage to the engine.