Daily maintenance knowledge of engineering machinery engine
writer:ld-driller | time:2020-09-03 16:25:24

1. Diesel

Diesel with good quality should be selected. The less moisture and mechanical impurities in diesel, the better. Otherwise, it is easy to cause early plug of filter, Rust of parts and serious damage of three coupling parts.

The brand selection of diesel should be correct. The freezing point of diesel is 6 ~ 10℃ lower than the lowest ambient temperature of diesel engine when it is used, ensuring its necessary mobility. The viscosity of fuel during the running of diesel engine is more than or equal to 1.3.

When the seasonal temperature changes, the diesel of the corresponding brand must be replaced. For example, in the case of minus 10 degrees, no.-10 diesel should be replaced.

2. Engine oil

The special engine oil of shangchai D114 series diesel engine with quality grade of CF-4 produced by Sinopec Great Wall lubricating oil company is selected. Most climate uses 15W/40 engine oil.

3. Coolant

The coolant of diesel engine requires a mixture of water and DCA4 chemical additives or antifreeze and DCA4 chemical additives in a certain proportion.

Note when using coolant:

1. The freezing point of the coolant should be about 10℃ lower than the lowest temperature in the region where the diesel engine is located.

2. Direct cooling of diesel engines by seawater is not allowed.

3. Do not use 100% ethylene glycol as coolant.

4. A certain concentration of DCA4 chemical additive must be added to the coolant. Water and antifreeze have no protective effect on the diesel engine cooling system.

5. DCA4 of different models and manufacturers cannot be mixed.

4. Starting of diesel engine

Before starting the diesel engine each time, the following items should be checked to eliminate hidden troubles as soon as possible and avoid accidents.

1 • check whether each part of the diesel engine is normal, including: appearance, pipeline, connecting part, etc.

2 • Check whether the circuit wiring of the electric starting system is correct and whether the power of the battery is sufficient. Shangchai company requires two models to be equipped with 6-Q-195, the calibration voltage to 12V and the capacity to be 195Ah.

3. The oil level, diesel level and cooling liquid level must be checked. The insufficient ones should be added to the regulated plane according to the requirements and regulations. The oil circuit and waterway switches should be in the open state..

4. Diesel engine must start without load, because normal starting is affected by four factors:

a battery model and actual power

B ambient temperature. It affects the discharge rate of the battery and the starting resistance moment of the diesel engine.

c starting resistance moment. It includes internal friction resistance moment, initial compression resistance moment and inertia moment needed to overcome to accelerate the engine from static stop state to starting speed.

d calibration power of starting motor. It is a power device used to overcome the starting resistance torque to make the diesel engine start, and the energy completely comes from the storage battery. Therefore, when the diesel engine starts with load, the starting resistance torque is increased, which causes the starting motor to work overloaded, which is not allowed.

5. Preheating of diesel engine

Heat soak must be carried out after each start, idle no-load should not exceed 10 minutes, then gradually accelerate and load. Only when the coolant temperature is 55℃ and the oil temperature is higher than 45℃ and the oil pressure is less than 0.7MPa can it be allowed to enter full load operation.

Purpose of heat soak: build oil film on the surface of the cylinder liner and other sports pairs, make the piston expand and cooperate with the cylinder liner, make the coolant heat up before the vehicle starts, make the whole machine temperature rise evenly, lubricate turbocharger bearing, etc.

IV. Start after stopping for a long time or changing the engine oil

1 • when starting the diesel engine after changing the engine oil or stopping for more than 30 days, the lubricate system must be filled with engine oil first.

2. Close the throttle or remove the parking electromagnet connecting wire (with electromagnet) to prevent the diesel engine from igniting and starting.

3 • use starter motor to rotate the crankshaft until oil pressure gauge indicates the pressure.

4. Open the throttle or connect parking electromagnet wires. Then start according to normal operation.

V. Starting of new or overhaul diesel engine

New or overhaul diesel engines can be put into full load only after running-in for a certain period of time. During the first 60 hours of use of diesel engine for construction machinery, the rotating speed should be controlled within 80% of the rated rotating speed, and the power should be controlled within 75% for running-in operation. Idle time must not exceed 5min.

6. Precautions during operation

I. Diesel engine cannot be overloaded, and diesel oil, engine oil and coolant that do not conform to the regulations cannot be used for over-rotating speed operation.

1.1 Informal diesel, engine oil and coolant will seriously damage the diesel engine;

1.2 The diesel engine should not be overloaded or overspeed, otherwise it will cause damage to the diesel engine and reduce the service life of the diesel engine. Of course, other parts in the whole machine, such as gearbox, clutch and chassis, will also be damaged.

II. When the car goes downhill, injection pump cannot control the rotation of the engine.

Speed, the driver should choose the appropriate gear and match the foot

Actuator and exhaust brake to prevent reverse speed!

III. Diesel engines are not allowed to run at high speed for a long time, for a long time

High speed is easy to cause oil leakage before, rear oil seal, and even lead to oil supply

Unstable, partial lubrication is insufficient.

IV. 80-100 hours of initial use of diesel engine

Within (grinding period), it should not exceed 80% load operation.

4.1 if the diesel engine cannot be fully run-in, in the future use, the power and economy of the diesel engine will be reduced.

4.2 After fully running-in, the diesel engine can make up for the shortage of processing and assembly quality to a certain extent. It can make the diesel engine coordinate well with all dynamic matching parts, and wear off the bulges on the dynamic matching surface, clean the metal scraps attached to its surface by oil.

V. The diesel engine can not be used in the production door. Reasons:

5.1 fierce oil extraction door increases the circulating oil supply rapidly, while the rotating speed is basically unchanged (hysteresis) at this time, and the circulating charge is also unchanged, resulting in the decrease of excess air coefficient and incomplete combustion of fuel due to hypoxia, exhaust black smoke.

5.2 The rapid increase of oil volume leads to the rapid increase of rotating speed, because the transmission of torque is output by the shaft, it is bound to increase the torsion torque of the shaft in a very short time, causing torsion deformation and even fracture of the shaft.

7. Engine Daily Service content

Preventive maintenance of diesel engine starts from knowing the working status of itself and its system every day. Before starting, daily maintenance should be carried out, check the oil and coolant surface, and look for possible leaks, loose or damaged parts, worn or damaged tape and any changes of diesel engine.

1 • check the oil level of the engine oil

To check the oil level, the engine oil should flow back to the oil pan after stopping the diesel engine (at least 5 minutes). When the oil level is lower than the mark of "L" (low oil level) on dipstick or higher than the mark of "H" (high oil level), the diesel engine is never allowed to be started.

2 • Check the coolant surface

Open the radiator or expansion tank water inlet cover or liquid level check bulkhead check the coolant level.

Note: fill the radiator or expand water tank filler or the bottom of the liquid level inspection port when entering the coolant. If there is intercooler, open deflation valve to remove the air from the coolant. Add it slowly to prevent gas resistance.

3 • Check the transmission tape

Check the transmission tape with naked eyes. Check whether the transmission tape has crisscross cracks. Transverse cracks along the width of the tape are allowed, but longitudinal and transverse cracks are not allowed. If the tape is worn or the material is peeled off, it should be replaced.

4 • Check cooling fan

It is required to check whether the fan has cracks, rivets are loose, blades are loose and bent with naked eyes every day. Ensure reliable fan installation. If necessary, tighten the fastening bolts and replace the damaged fan.

5. Remove water and sediment from the fuel-water separator.

If any, it should be excluded until the clean fuel flows out, and then close the valve. Note that if there is too much sediment discharged, the fuel-water separator should be replaced to avoid affecting the smooth start of the diesel engine.







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