Maintenance for Main Accessories of Natural Gas Engine
4.2 Operation and maintenance specifications for main accessories of natural gas engines
1. Maintenance of gas line
1. The gas filter shall be maintained regularly. Check whether the gas line is blocked and replace the gas filter element once every 300 to 500 operation hours of engine.
2. The natural gas to be used shall be standard LNG or CNG. If the poor quality natural gases containing a high impurity or water content, e.g. methane or coal bed methane is used, they must receive coarse filtration and dehydration treatment before entering into engine; otherwise, the engine performance will be influenced and the service life of engine will be shortened.
2. Maintenance of inter-cooling water tank
1.Cleaning of water radiator
Water radiator shall maintain usually to ensure the heat exchange between coolant and water. Generally, the surface and interior of water tank shall be cleaned as engine operate per 500 h. when clean the internal incrustation and impurity, the operator shall release the water in the water radiator and fill rinsing (like tap water) with press into radiator core, until clean water outflow.
2. Daily matters need attention
The pressure cover shall be closed to keep the cooling system`s operation when engine runs. And user need check the coolant quantity usually and supplement the coolant timely, less coolant may affect cooling performance, and accelerate cavitation erosion of engine. Adding coolant at that moment must be careful to avoid hot steam.
Attention: Be sure not to open the radiator pressure cover when engine runs at heavy load, the best moment to open the cover is until the water temperature under 70℃ after the engine stop. Before engine runs, fill the coolant into the empty radiator slowly, refill after about two minutes until the air in cooling system get out. When engine runs in low-temperature environment, user shall open water drain valve immediately after engine stop and release water in radiator to avoid to frost the radiator.
3. Operation and maintenance of air filter
Warning! The service life of your engine may be shortened greatly due to wrong maintenance methods.
1. The air filter shall match the performance index of engine in a strict way; otherwise, the dynamic property and economy performance of engine will be influenced.
2. If the air filter is provided with a warning device, the warning device shall be observed first before the natural gas engine is started. When the intake resistance indicator give an alarm (turns red), the air filter element shall be maintained.
3. The filter adopting multistage filtration technology must be provided with a coarse strainer.
4. When mounting the dust exhausting pipe, the pipe shall not be bend sharply and shall be free from air leakage.
5. Prevent water from entering into the air filter.
6. When maintaining an air filter with a safety filter element, do not disassemble the safety filter element.
7. In normal working conditions, the paper main filter element of fine filter shall be maintained once every 100 to 200 operation hours of engine. Remove the main filter element and tap or shake off the dust inside. Check each sealing element of it and replace any damaged one. The clean and dry compressed air not exceeding 500kpa may be used from blowing from inside of filter element. Put a lit bulb inside the filter element and observe externally whether any light can pass through the filter element, in order to confirm whether there is crack, pierced hole or other damages. Cleaning the main filter element with oil or water is strictly prohibited.
8. The main filter element shall be replaced after having working for 1000 to 2000 hours. In the meantime, the safety filter element shall be replaced.
9. The filter element assembly shall be replaced in the following cases:
1) The filter element is broken.
2) The warning device is still giving alarm after a clean filter element has been mounted.
3) After the filter element has been cleaned up for 3 to 6 times.
When replacing a filter element, the operator must use the filter element of a reliable quality in order to guarantee the reliability of engine. It is recommended to purchase the genuine parts.
4. Operation and maintenance of turbocharger
The engine oil of turbocharger is drained from the main oil line of engine, and returns to the bottom of crankcase after lubricating and cooling the turbocharger are complete.
1. A good lubrication is crucial to the normal operation of turbocharger. Therefore, the engine oil filter element shall be cleaned up or replaced regularly.
2. The turbocharger works at an extremely high rotating speed (about 70000 to 100000r/min). Therefore, the engine shall run idle (for about 5 minutes; the duration may be shortened as appropriate in case of a short-term shutdown) before it is loaded. Do not shut down the engine immediately when it is running at a high speed under a heavy load. The load and rotating speed shall be lowered gradually and the engine shall idle for 3 to 5 minutes; otherwise the turbocharger bearing will be damaged and become unusable.
3. Disassemble and check the compressor casing and turbine casing regularly, and clean up the impeller and the flow passage in casing. When reassembling the turbocharger, fill clean engine oil via the filler opening.
5. Operation and maintenance of starter
1. Starter is a short-time service device. Its starting time shall not exceed 15S every time. The interval between successive starting shall be longer than 30S.
2. The engine shall be preheated when the temperature is below 5℃ in winter.
3. Release the starting switch immediately once the engine is started up so as to disengage the drive gear of starter from the flywheel ring gear.
4. Energizing the starter before the engine stops running is strictly prohibited, so as to avoid damage due to collision between the flywheel and the starter gear.
5. The wiring of a starter must be based on the wiring diagram of the starter during installation. Make sure that the battery is disconnected from the main starting line of starter.
6. The fastening pieces of starter and wire insulation must be checked frequently for damage; the wires shall be well-contacted and the dirt shall be removed.
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