Diesel generator sets are widely used in industrial, construction, communication, and other fields. They can provide reliable power support when the grid is unstable or during power outages, ensuring the normal operation of equipment. However, many users have some incorrect operating habits during use. These habits not only reduce the performance of the generator sets but may also cause equipment damage or even safety accidents. This article will detail the common incorrect operations of diesel generator sets and provide correct operating methods to help users better maintain the equipment and extend its service life.
During daily use of diesel engines, the operational details before shutdown are often overlooked. Correct shutdown operations not only protect key engine components but also avoid costly repairs caused by improper operation.
After the diesel engine shuts down, the circulation of cooling water stops, and the heat dissipation capacity drops sharply. Heated parts lose cooling, which can easily cause overheating of the cylinder head, cylinder liner, cylinder block, and other components, leading to cracks, or cause the piston to expand excessively and seize in the cylinder liner. On the other hand, if the diesel engine is not cooled at idle before shutdown, the lubricated surfaces may lack oil, and when the diesel engine starts again, poor lubrication will accelerate wear.
Correct Operation: Before shutting down the diesel engine, unload the engine and gradually reduce speed, running it unloaded for a few minutes. This ensures that all parts are sufficiently cooled before shutdown and reduces damage caused by rapid temperature changes.
Before shutting down the diesel engine, if the oil supply is insufficient, the lubrication of friction surfaces will be inadequate, causing abnormal wear or scoring. Therefore, before starting the machine and during diesel engine operation, ensure sufficient oil to prevent cylinder scoring or bearing damage caused by oil shortage.
Correct Operation: Regularly check the oil level to ensure sufficient oil. Before startup and during operation, check whether the oil pressure is normal to ensure that the lubrication system is functioning properly.
Low cooling water temperature may cause a series of problems, affecting engine performance and service life. Understanding these issues and taking correct measures can effectively prevent equipment damage caused by low cooling water temperature.
During diesel engine operation, if the cooling water temperature is too low, the cylinder wall temperature drops, and the water vapor generated by combustion condenses into droplets. These droplets contact exhaust gases to form acidic substances, which attach to the cylinder wall and cause corrosive wear. Practice has shown that when diesel engines are often used with cooling water at 40–50°C, the wear of parts is several times higher than when operating at normal temperatures (85–95°C).
Correct Operation: Maintain the cooling water temperature within the normal working range (85–95°C). Regularly inspect the cooling system to ensure that components such as the radiator and water pump work properly. In cold seasons, antifreeze or insulation measures can be used to prevent excessively low cooling water temperature.
When starting a diesel engine at low temperatures, if the cooling water temperature is too low, the cylinder temperature is low, extending the ignition delay period. Once ignition occurs, the pressure rises rapidly, fuel burns roughly, and mechanical damage to components may occur. In addition, the large clearance between the piston and cylinder liner can easily cause cylinder knocking, producing vibrations and pitting the cylinder liner.
Correct Operation: In cold seasons, preheat the engine before startup to ensure the cooling water temperature reaches a certain level. Heaters or hot water can be used to preheat the cooling system to prevent low-temperature startup from damaging the equipment.
During operation, temperature management of the diesel engine is a key factor in ensuring its stability and durability. When the diesel engine temperature is too high, failure to take correct measures may cause severe mechanical failure.
If cooling water is added suddenly when the diesel engine is overheated due to lack of water, the cylinder head, cylinder liner, cylinder block, and other components may crack due to the drastic temperature change.
Correct Operation: When the diesel engine temperature is too high, first unload the engine, slightly increase the speed, and wait for the water temperature to drop before shutting down the diesel engine. Loosen the radiator cap to release steam, and if necessary, slowly add cooling water to the radiator.
When the diesel engine idles, oil pressure is low, and the piston top is poorly cooled by injected fuel, causing rapid wear and possible scoring. It may also result in poor atomization, incomplete combustion, severe carbon deposition, and sometimes even seizure of the valves and piston rings or pitting of the cylinder liner.
Correct Operation: The diesel engine should not idle for more than 15–20 minutes. After startup, raise the engine speed to the normal working range as soon as possible to avoid prolonged idling.
The startup process of diesel generator sets is a critical stage of use. Correct startup operations ensure smooth operation, while incorrect operations may damage the equipment.
During diesel generator startup tests, some users immediately attempt a second start if the first attempt fails. In reality, the engine on a diesel generator works under high current and low voltage conditions, and prolonged use may damage the battery. In addition, the interval between continuous start attempts should not be less than 5 seconds. If the first start fails, wait 15 seconds before trying again.
Correct Operation: When starting a diesel generator, if the first attempt fails, wait 15 seconds before trying again. Continuous starting time should not exceed 5 seconds to avoid damage to the battery and engine.
After starting, diesel generator sets should not immediately run at high speed or carry load. This is particularly important in cold seasons. After starting, the diesel engine should run unloaded at idle or low speed (800–1000 rpm) for 3–5 minutes before applying load.
Correct Operation: After startup, let the diesel engine run unloaded at idle or low speed (800–1000 rpm) for 3–5 minutes, allowing the components to warm up and lubrication to be sufficient before applying load.
Daily maintenance is an important part of ensuring long-term stable operation of diesel generator sets. However, many users make errors during daily maintenance, which can reduce performance and damage equipment.
Different brands and grades of oil are produced differently. Mixing two different brands of oil often causes precipitation and deterioration, which adversely affects the diesel engine and may lead to equipment failure.
Correct Operation: When selecting oil, choose the appropriate grade according to local seasons and temperatures, and pay attention to the oil quality and viscosity rating. Do not mix different brands of oil.
Do not place the decompression lever in the "work" position before refueling during engine startup. Incorrect operation can waste fuel; excess diesel may wash cylinder walls, worsening lubrication between the piston, piston rings, and cylinder liner, increasing wear; excess fuel may flow into the oil pan, diluting the oil and reducing lubrication; unburned diesel in the cylinder may form carbon deposits.
Correct Operation: Before startup, place the throttle in the refueling position to avoid unburned diesel washing cylinder walls and diluting oil.
Careful use of glow plugs and flame preheaters is necessary to ensure safety and extend equipment life. These devices use electric heating elements, consuming significant power and generating intense heat. Overuse may rapidly discharge the battery and damage the heating element, affecting overall performance.
Correct Operation: Limit glow plug use to no more than 1 minute and flame preheater use to within 20 seconds to avoid overuse.
Winter: In cold seasons, after starting, run the engine unloaded at idle or low speed (800–1000 rpm) for 3–5 minutes before applying load. If the ambient temperature is below 5°C, start the diesel generator heater.
Correct Operation: Preheat the engine before startup in cold seasons to ensure cooling water reaches the required temperature. Use heaters or hot water to preheat the cooling system to prevent low-temperature startup damage.
Summer: After load operation, before shutdown, unload and run at idle or low speed (800–1000 rpm) for 3–5 minutes until the temperature drops before turning off.
Correct Operation: In high-temperature summer conditions, after load operation, first unload the engine, run at idle or low speed for 3–5 minutes, and then shut down after the temperature decreases to avoid damage due to overheating.
Many users make mistakes when replacing lubricating oil and fuel, which may damage the equipment. The following are common mistakes and correct methods for oil and fuel replacement to help maintain the equipment.
Failure to replace oil and fuel on time causes problems. In cold seasons, not replacing lower-viscosity oil and fuel in time may make the diesel engine difficult to start.
Correct Operation: Regularly check the quality of oil and fuel, and replace appropriate lubricating oil and fuel in time according to the season and usage. In cold seasons, replace with lower-viscosity oil and fuel to ensure smooth startup.
Heating the oil pan of the diesel generator with open flame or igniting in the intake pipe is unsafe and may cause fire.
Correct Operation: Use mild flame or coal fire from a safe distance to heat the oil pan, slowly rotate the crankshaft so the oil is heated evenly and all parts are lubricated. Avoid direct open flame heating to prevent fire.
In addition to the common errors mentioned above, there are other improper operations that can also negatively affect diesel generator performance and service life.
Pouring gasoline directly into the intake is not recommended. Gasoline has a lower ignition temperature than diesel and may ignite prematurely, causing unstable engine operation or knocking.
Correct Operation: Do not pour gasoline directly into the intake pipe. Use appropriate starting fluid or auxiliary devices if startup performance needs to be improved.
Adding oil directly to the cylinder to improve sealing or heating is not advisable. Although low temperatures can help engine startup, oil cannot fully combust and may leave residues in the cylinder, causing various problems.
Correct Operation: Do not add oil directly to the cylinder. Use appropriate starting fluid or auxiliary devices if needed.
Immediately running at high speed after startup is unwise. At the beginning of startup, low oil temperature and poor flow can cause rapid wear of moving parts, and severe cases may lead to bearing or piston seizure.
Correct Operation: After startup, run the engine at low speed for a period, then gradually increase speed after the oil temperature rises and flow improves.
High-frequency startup can damage the battery. The engine operates under low voltage and high current. Continuous start attempts should not exceed 5 seconds, and after a failed attempt, wait 15 seconds before trying again.
Correct Operation: Continuous startup should not exceed 5 seconds. If the first attempt fails, wait 15 seconds before trying again to avoid battery damage.
Correct operation of diesel generator sets is crucial to equipment performance and service life. By avoiding the common incorrect operations mentioned above, users can significantly reduce equipment failures and extend service life. Regular maintenance and inspection, ensuring normal conditions of lubricating oil, cooling water, and other systems, are key to safe and reliable operation. This article aims to help users better operate and maintain diesel generator sets, ensuring stable and efficient operation under various working conditions.
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