Causes and troubleshooting methods of diesel generator sets?

There are three main reasons for the cylinder knocking of diesel generator sets:

1. After the oil outlet valve is worn, on the one hand, the gap between the pressure reducing ring belt and the inner hole of the valve seat becomes larger, the sealing becomes poor, and the pressure reduction effect becomes worse; On the other hand, the residual pressure in the high-pressure oil pipe is too high, and the oil supply increases, causing the fuel to deflagrate and knock the cylinder. The knock on the cylinder is especially noticeable when the throttle is reduced.

2. Premature oil supply time will lead to the failure of the cylinder of the unit. When the upward movement of the generator piston has not reached the specified injection position, the injector begins to inject fuel, so that the fuel combustion is advanced, and the high-pressure gas in the cylinder hits the piston, making a rhythmic "click, click" crisp knocking sound, reducing the throttle, and the knocking sound is obvious.

3. The fuel injection pressure is too low, the injector drips, the fuel injection atomization is poor and the oil supply time is too late, etc., which will cause poor fuel combustion and cause cylinder knocking. This type of failure causes a muffled, hoarse knocking sound and is accompanied by engine overheating, black smoke or exhaust pipe discharge, fire and other phenomena. The injector should be removed for inspection and adjustment, adjust the oil supply time, and replace new parts if necessary to make it comply with the regulations.

Troubleshooting method of diesel generator set knocking cylinder:

1. After the engine starts, there is a knocking sound when running at low temperature, and after the temperature is normal, the sound disappears, and it can be temporarily left unprocessed and continue to run.

2. When the engine temperature is normal, there is an obvious knocking sound, try to avoid high-speed operation, and disassemble and repair as soon as possible.

3. After removing the cylinder head and pulling out the piston, it is found that the cylinder is seriously out of round, strained, or the gap between the piston and the cylinder is too large, and the cylinder liner, piston and piston ring should be replaced.

4. If the connecting rod is found to be deformed, it should be replaced as much as possible. The piston knocking sound of diesel generator set occurs on the cylinder block and in the middle (equivalent to the full length of the cylinder liner), which is a rhythmic "rattling" sound, the exhalation is continuous and dull, and the speed is higher and more obvious, and the above measures can be taken.

Precautions for knocking cylinders on diesel generator sets:

1. If the cylinder of the unit is faulty, the parts of the unit should be replaced in time.

2. Pay attention to the inspection and maintenance of the unit in the process of using the unit!

The oil supply time is too early. When the diesel engine piston moves upward, the injector will start injecting fuel when it does not reach the specified injection position, resulting in premature fuel combustion. This creates a high-pressure gas impingement piston that causes the cylinder to produce a rhythmic, crisp "click, click" sound.

At the same time, the throttle will be lowered, and the knocking sound is very noticeable. The reasons for the knocking of the cylinder of the diesel engine are as follows:1

The gap between the piston and the cylinder is too large. Due to improper repair, the gap between the piston and the cylinder is large, or the cylinder is seriously worn and the gap is too large. When the engine is low, the piston clearance is large, and the cylinder knocking sound is serious.

When the engine temperature rises, the piston expands, making the piston fit clearance smaller, and the cylinder knocking sound decreases or disappears. 2.The piston direction is reversed or the piston is deformed, which destroys the normal gap between the piston and the cylinder, causing the piston to knock the cylinder.

3.Poor lubrication of the cylinder wall. Poor lubrication conditions, low oil pressure or low oil viscosity, poor lubrication of cylinder wall splashing, normal lubricating oil film can not be formed between the piston and the cylinder wall, and the piston and the cylinder collide directly and knock the cylinder.

If not, then what may be the cause of the knock cylinder, is it that the diesel car can not run 120 for a long time Zhengzhou Nissan diesel pickup truck knock cylinder, the repair shop said that it was caused by running 120 on the highway, I want to ask if there is such a thing? How to avoid knocking on the cylinder? Note There are two types of diesel engine cylinders:

The first is the fuel knock cylinder, which is caused by the premature injection angle. The oil supply of each cylinder is uneven. The second is mechanical knocking, which is caused by the excessive gap between individual moving parts.

Common causes (1) The gap between the piston and the cylinder is too large. Due to improper repair, the piston and the cylinder fit gap is large, or the gap is too large due to serious cylinder wear. When the engine is low temperature, the piston gap is large, and the cylinder knocking noise is serious, and the piston expands after the engine temperature rises, so that the piston matching gap becomes smaller, and the cylinder knocking noise is reduced or disappears.

2) The piston direction is reversed or the piston is deformed, which destroys the normal clearance between the piston and the cylinder, resulting in the sound of the piston knocking the cylinder. (3) Poor lubrication of the cylinder wall. Poor lubrication conditions, low oil pressure or low oil viscosity, poor splash lubrication of the cylinder wall, normal lubricating oil film can not be formed between the piston and the cylinder wall, and the piston and the cylinder directly collide and knock the cylinder.

4) The connecting rod is bent or twisted and deformed, and the assembly of the piston connecting rod group makes the piston skew in the cylinder beyond the allowable range, which not only deteriorates the sealing and deterioration of the lubrication condition, but also causes abnormal wear of the cylinder, so that the piston and the cylinder wall knock and make a sound. (5) The lubricating oil channel is blocked, and normal pressure lubrication cannot be formed; The connecting rod bearing or piston pin is too tight, causing the piston to collide with the cylinder wall during the movement and make a sound. (6) Serious carbon deposition in the combustion chamber.

When there is too much carbon in the combustion chamber, the compression ratio of the diesel engine increases, the gas pressure and temperature are too high, and the mist diesel injected into the cylinder ignites and burns when it encounters high temperature and high pressure gas, resulting in the so-called detonation. During detonation, the flame propagates outward at an extremely high rate, and even when the gas does not have time to expand, the temperature and pressure rise sharply, forming a pressure wave that advances at the speed of sound. When this pressure wave hits the cylinder wall, it makes a sharp knocking sound.

7) The injection advance angle is too large. When the injection advance angle is too large, that is, the mist diesel fuel is injected into the air earlier to form a combustible mixture, after the engine reaches the normal working temperature, even if the pressure in the cylinder does not reach the normal working pressure at this time, the working temperature in the cylinder is easy to rise to the ignition point of the diesel, so that the combustible mixture in the cylinder is rapidly burned and expanded, and the pressure in the cylinder rises rapidly, and the highest point of the cylinder combustion pressure is advanced due to the rapid expansion of the gas in the cylinder, resulting in excessive pressure in the cylinder, and the horizontal component of the piston increases. The force of striking the cylinder wall increases, resulting in a cylinder knocking sound. (The injection advance angle is too small and has nothing to do with this abnormal noise).

8) The combustion speed of the combustible mixture is too fast, which causes the pressure in the cylinder to be too high, and the piston skirt hits the cylinder wall and there is a cylinder knocking sound. (9) The cylinder gasket is too much or the top surface of the cylinder block is ground too much, resulting in an increase in the compression ratio of the diesel engine (a large compression ratio is a major feature of the diesel engine), causing a deflagration and a knocking sound. @2019

Summary. Hello, I'm glad to answer for you, the reasons for knocking on the cylinder of the multi-cylinder diesel engine are as follows: 1. The oil supply time is too early:

When the upward movement of the diesel engine piston has not reached the specified injection position, the fuel injector begins to inject fuel, so that the fuel combustion is advanced, and the high-pressure gas in the cylinder hits the piston, making a rhythmic "click, click" crisp knocking sound, reducing the throttle, and the knocking sound is obvious. 2. Poor fuel combustion: too low fuel injection pressure, oil dripping from the injector, poor oil injection atomization and too late oil supply time will cause poor fuel combustion and cause cylinder knocking.

3. Wear of the oil outlet valve: After the oil outlet valve is worn, on the one hand, the gap between the pressure reducing ring belt and the inner hole of the valve seat becomes larger, the sealing becomes poor, and the pressure reduction effect becomes worse; On the other hand, the residual pressure in the high-pressure oil pipe is too high, and the oil supply increases, causing the fuel to deflagrate and knock on the cylinder, and the knocking sound is especially obvious when the throttle is reduced. Hello dear, I hope my answer can help you, and I wish you a happy life and good health!!

Hello, I have seen your question, and I am sorting out the answer for you, please wait for a while Oh Kiss, hello, I am happy to answer for you, kiss the multi-cylinder diesel engine knock cylinder for the following reasons: 1, the fuel supply time is too early: when the diesel engine piston upward movement has not reached the specified fuel injection position, the fuel injector begins to inject fuel, so that the fuel combustion is advanced, the high-pressure gas in the cylinder hits the piston, and makes a rhythmic "click, click" crisp knocking sound, reduce the throttle, and the knocking sound is obvious.

2. Poor fuel combustion: too low fuel injection pressure, oil dripping from the injector, poor oil injection atomization and too late oil supply time will cause poor fuel combustion and cause cylinder knocking. 3. The oil outlet valve is worn clearly

After the oil outlet valve is worn, on the one hand, the gap between the pressure reducing ring and the inner hole of the valve seat becomes larger, the sealing becomes poorer, and the pressure reduction effect deteriorates; On the other hand, the residual pressure in the high-pressure oil pipe is too high, and the oil supply increases, causing the fuel to deflagrate and knock on the cylinder, and the knocking sound is especially obvious when the throttle is reduced. Hello dear, I hope my answer can help you, and I wish you a happy life and good health!! Take the bend!!

Generally, the crankshaft axial clearance is too large, causing the crankshaft to move and cause the cylinder to knock! To change the thrust spacer!

single-cylinder diesel engine knock cylinder; First, due to the premature fuel supply time, the diesel fuel in the cylinder in advance deflagration to push the sound of the piston, second, or the usual soothing of the pretense juice accompanied by Tong Bao Kuo plug pin and the connecting rod copper sleeve caused by the knocking sound, third, there is also the injector injection abnormal will also cause the diesel engine to knock on the cylinder.

The engine makes a knocking sound is an abnormal fault, and the direct phenomenon is to pull the cylinder, and the common reasons for the failure are:

1. The amount of engine lubricating oil is reduced, which causes the cylinder liner and piston group to wear and pull the cylinder;

2. The engine cooling system components work poorly or are damaged, resulting in high engine temperature, which makes the piston stick to the cylinder and pull the cylinder;

3. The engine runs overload for a long time;

4. The supporting quality of engine 6 is not good;

5. The engine lubricating oil specification does not match the specified model of the engine;

6. The quality of the lubricating oil used in the engine is not good;

7. Oil consumption increases due to turbocharging damage;

8. Reasons for maintenance and assembly level, etc.

1. Detonation, commonly known as knocking cylinder and calling rod. Detonation is an abnormal combustion phenomenon that occurs during the combustion of an engine. To put it simply, "knocking" is a phenomenon of abnormal combustion of the engine.

Detonation is an abnormal pressure in the combustion chamber caused by abnormal combustion. When the engine knocks, it makes a knocking sound. The slight discontinuous knocking sound is quite crisp, somewhat similar to the sound of tapping a triangle.

In the event of severe and continuous detonation, the engine will have a "mile-mile" sound, and the engine will also be obviously weak at this time.

1. There is an irregular metal knocking sound of "clang", "click" and "dangdang" in the engine.

2. Engine tremor.

3. The engine temperature is too high.

4. The fuel combustion is incomplete, and there is black smoke in the exhaust gas.

5. The engine power decreases.

6. Increased fuel consumption.

7. During normal driving, the speed suddenly changes inexplicably.

Second, the main reasons.

1. The ignition angle is too advanced: in order to make the piston get power immediately after entering the power stroke after the end of compression top dead center, it is usually ignited in advance before the piston reaches the top dead center (because it takes a while 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.

2. Excessive carbon deposition in the engine

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.

4. 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.

5. The octane number of fuel 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.

3. Inspection and maintenance.

1. Detect the change of engine combustion chamber pressure; Detect the vibration frequency of the engine block; Detection of combustion noise of gas mixtures.

2. The measurement accuracy of directly detecting the pressure change of the combustion chamber to detect the vibration of the engine is high, but the sensor is difficult to install, and the durability is poor, so it is generally used for measuring instruments, and the pressure detection sensors in practical applications are indirect detection type.

3. The fastest and most effective way to suppress detonation is to delay the ignition advance angle and reduce the combustion pressure. Therefore, the working principle of the knock sensor is that when the engine knocking is detected, the ignition advance angle will be delayed to the ignition time when the detonation will not be detonated, and then the ignition will be slowly restored in advance when the engine does not detonation.