Xichai engine is replaced with a new oil pump, and there is a knocking sound, how to eliminate the m

Diesel engine piston knocking mostly occurs shortly after the diesel engine is severely worn or overhauled. When the diesel engine has this fault, it should be eliminated in time.

Method of exclusion:

1) Fix the speed of the diesel engine at the position where the knock is loudest, and take the cylinder-by-cylinder oil cut-off method for testing. If the high-pressure oil pipe of a cylinder is removed, if the sound is significantly reduced or disappeared when the cylinder is tried, it proves that the piston of the cylinder is striking the cylinder wall.

2) Touch the middle of the cylinder with a stethoscope stick, the sound of slapping can be clearly perceived, and the sound area is fresh, and there is a slight sense of vibration, at this time should pay attention to careful auscultation, because when the diesel engine is working, its noise and vibration are its working characteristics, so it should be carefully distinguished.

3) When the diesel engine is idling, the piston knocking sound is obvious and clear, and the sound is weakened or disappeared as the water temperature of the diesel engine rises or the speed is above medium speed.

4) Remove the injector, fill a small amount of oil into the cylinder from its mounting hole, use the starter to drive the diesel engine crankshaft to rotate a few times, fill the piston with a lubricating oil film between the cylinder wall, and then start the diesel engine. If the sound is significantly reduced or disappeared immediately after activation. However, with the loss or ablation of the oil film, the sound will appear very quickly, indicating that the abnormal knocking sound occurs in the cylinder.

5) Remove the cylinder head and check the carbon deposits in the combustion chamber of the diesel engine. If there is too much carbon in the combustion chamber of a diesel engine, it should be removed by mechanical or chemical means.

6) After removing the cylinder head, check the thickness of the cylinder head gasket. If the head gasket is too thin or the top surface of the cylinder block is ground too much, a thicker head gasket should be selected to prevent the compression ratio from increasing due to excessive reduction of the combustion chamber volume.

7) After removing the cylinder head, check and measure the wear degree of the cylinder, if the cylinder is worn too much or damaged, the cylinder should be shoeed or replaced according to the repair specification.

8) Pull out the piston connecting rod group, and measure the matching clearance between the piston and the cylinder and the matching clearance between the piston pin and the piston pin hole with the outer diameter micrometer and the cylinder gauge to see if it meets the requirements of use.

9) Check the connecting rod. Check the bending and twisting of the connecting rod. If the deformation exceeds the limit, it should be corrected or replaced by cold pressing; Check the copper sleeve of the small head of the connecting rod, if the wear exceeds the limit, the copper sleeve should be replaced; The connecting rod and connecting rod bolts should be tested by magnetic force, and any form of crack in the connecting rod must be replaced.

10) When assembling, the piston installation direction should be checked, especially the diesel engine with piston pin offset design, the purpose is to reduce the opportunity of engine piston cylinder knocking, once the direction is reversed, it will inevitably lead to or aggravate the abnormal knocking sound of the engine.

It is recommended that you realign the high-pressure pump, most of them are backwards, and the sound is good in advance, and the power is also great!

One is the drag gear, the other is the early ignition time, and the other is the hardware problem. The sound of the plug knocking is a crisp and rhythmic metal striking sound that is consistent with the number of work.

Summary. Hello, I am your exclusive technician, attentive, careful, dedicated to answering your car questions, for you to find the corresponding problem solutions and solutions! The reason is that the inside of the engine burns badly.

1.Fuel quality problems will lead to insufficient fuel combustion, which will lead to cylinder knocking. 2.

Low-pressure pipes if they are clogged. It can also lead to poor oil supply. It then affects the normal operation of the engine and causes the cylinder to knock.

You can change the fuel first. Or inspect low-pressure pipes.

Hello, I am your exclusive technician, attentive, careful, dedicated to answering your car questions, for you to find the corresponding problem solution and solution! The reason is that the inside of the engine burns badly. 1.

Fuel quality problems will lead to insufficient fuel combustion, which will lead to the phenomenon of cylinder knocking. 2.Low-pressure pipes if they are clogged.

It can also lead to poor oil supply. However, after the judgment of the pants, it affects the normal operation of the engine and causes the cylinder to knock. You can change the fuel first.

Or inspect low-pressure pipes.

There are two kinds of high-pressure oil pumps, one is when it needs to be aligned, the other is when it needs to be aligned, and the high-pressure oil pump that does not need to be aligned only has two oil pipes. If you make a mistake, it will not affect the normal operation of the engine.

If it is the kind of oil pump that needs to be aligned. If it is installed incorrectly, it will affect the acceleration of the engine, and there will be a knocking sound.

Hello pro detonation, commonly known as knocking on the cylinder, calling the 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 is sluggish, and the sock ridge decreases.

6. Increased fuel consumption. 7. During normal driving, the speed suddenly changes inexplicably. Second, the main reason 1, the ignition angle is too early:

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 (since 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. Code infiltration 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: The engine temperature is too high in a too hot environment, or the engine cooling water is poorly circulated, which will cause the engine to detonate due to high temperature.

4. Incorrect air-fuel ratio: Too thin 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 detonate. 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.

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.