3. What are the main reasons for early wear of loader forklift diesel engine?
The early wear of diesel engine refers to the phenomenon that the diesel engine can not continue to work effectively due to the wear of the main moving parts (such as piston ring, crankshaft, bearing bush, cylinder sleeve, etc.) in a relatively short service time, resulting in a significant reduction in the power of the diesel engine and an increase in fuel consumption. The early wear of diesel engine is mainly caused by the following reasons:
① The new machine operates under heavy load without running-in;
② Air filter failure;
③ Improper use and maintenance, poor oil quality;
④ Poor combustion causes excessive carbon deposition in the cylinder.
4. What is the cause of the cylinder liner of the loader forklift? How to prevent?
The main manifestations of the cylinder liner strain are: the piston in the cylinder has a knocking sound;
Diesel power is reduced; The engine oil burns and the smoke is blue or white; Oil thinning, pressure drop, etc.
I. The causes of cylinder pulling failure include:
① The cooling system fails, the machine overheats, and the piston expands too much after being heated;
② The oil is insufficient, deteriorated or contains impurities, resulting in poor lubrication;
③ The clearance between piston and cylinder wall is too small (mostly seen in new engines or newly overhauled diesel engines)
④ The piston ring is broken or stuck;
⑤ The piston pin circlip fails, causing the piston pin to move.
5. What are the measures to reduce the wear of cylinder liner of loader forklift?
To reduce the wear of cylinder liner, in addition to the measures of corrosion resistance and wear resistance in design and manufacturing, the following points should also be noted in the use and maintenance engineering:
(1) Correct starting and starting
After the cold start, the vehicle should be warmed up for 3 to 5 minutes under the condition of small throttle before starting the driving. At the beginning of the operation, the vehicle should work with a small load for a period of time, and then work with a large load after the temperature rises.
(2) Maintain the normal temperature of the engine
The temperature of diesel engine is too low to maintain good lubrication, which will increase the friction of cylinder wall; If the temperature is too high, it will reduce the strength of the cylinder and aggravate the wear, and may even cause the piston to expand excessively and cause the "cylinder pulling" accident. The normal working temperature of the diesel engine is 80 ℃~90 ℃. When the temperature exceeds 95 ℃, reduce the load or shut down for cooling.
(3) Keep good lubrication
Regularly check and keep the oil in good quality and moderate oil level, replace it regularly and select the oil with proper viscosity according to the season to ensure good lubrication.
(4) Strengthen the maintenance of "three filters" (air filter, oil filter and diesel filter)
This is the main measure to prevent mechanical impurities from entering the cylinder, reduce cylinder wall wear, and extend the service life of the engine, which is particularly important for the diesel engine of loader which is often in high dust content.
(5) Improve maintenance and quality
The maintenance and repair work shall be carried out in strict accordance with the technical standards specified in the diesel engine operation and maintenance manual. Adjust and control the fitting clearance (opening clearance) to prevent the wear between the piston and cylinder wall from being accelerated due to improper repair and maintenance.
6. What are the reasons why loader forklift diesel engines often flush cylinder pads?
The cylinder gasket is burned by the high temperature gas in the cylinder, which is called "cylinder gasket", also known as "cylinder gasket".
After flushing the cylinder gasket of diesel engine, there will generally be abnormal phenomena such as "bubbling" in the water tank, water ingress into the oil pan, oil emulsification, and exhaust pipe drainage (white smoke). The main causes of the cylinder washer are
(1) Cylinder head deformation
The cylinder head is subject to thermal deformation due to the alternating action of high temperature and high pressure gas for a long time; Improper disassembly and assembly (not in sequence) can also cause deformation. After the cylinder head is deformed, the warped part can not press the cylinder gasket tightly, resulting in high temperature gas leakage and burning of the cylinder gasket.
(2) The height of cylinder sleeve boss is different, which causes the sealing of individual cylinders to be not tight.
In order to make the cylinder liner and cylinder gasket tightly pressed on the cylinder block and maintain good sealing, it is generally required that the convex plane of the cylinder liner end face is higher than the cylinder block by a certain size (generally 0.05~0.12mm), and the difference of the convex amount of the cylinder liner of the same diesel engine (or two cylinders under the same cylinder head) is also specified (generally 0.05 mm).
If the specified value is exceeded, the sealing pressure may be insufficient, and the high pressure and high temperature gas may escape and damage the cylinder gasket.
(3) The cylinder head bolts are loose or the tightening torque is insufficient
When the diesel engine leaves the factory, the use and maintenance instructions provided by the manufacturer have clear requirements for the torque of the cylinder head fastening bolts. During maintenance, the cylinder head should be tightened strictly according to the specified time and method.
(4) The assembly method of cylinder gasket is incorrect or the quality of cylinder gasket is poor.
(5) The machine does not work well, and overheating causes the cylinder pad to be flushed.
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