How to Check the Low Oil Pressure of Diesel Generator Set

Low oil pressure of diesel generator set is a common fault in the use and maintenance of diesel generator set. When the oil pressure of diesel generator set is lower than 0.1MPa at idle speed of hot car, and lower than 0.2MPa at medium and high speed, the oil pressure is too low. How to check the low oil pressure of power generator?

1. Appearance inspection.

Check the quality and quantity of engine oil.

For the diesel engine with low oil pressure, it is generally necessary to check whether the oil quantity meets the requirements. If the oil quantity is too small, the fault is obvious. If the oil quantity meets the requirements or too much, it is necessary to carefully observe whether the oil has diesel oil and moisture. If the engine oil is mixed with diesel oil, the engine oil will become thinner and the viscosity will drop, resulting in low engine oil pressure.

Observe oil pressure sensor and oil pressure gauge.

Turn on the power (do not start the diesel engine at this time), and observe whether the pointer of the oil pressure gauge moves and returns to the 0 position accurately. If the pointer of the oil pressure gauge does not move or cannot return to 0, it means that the oil pressure gauge is inaccurate, or the oil pressure sensor is invalid, or the circuit is faulty.

A self-made direct pressure oil pressure gauge (modified with a pressure gauge of 0.1-1.0 MPa) can be connected in series on the main oil channel. The diesel engine can be started. If the oil pressure on the direct pressure gauge is normal, the fault is still on the relevant instruments and circuits. The pressure on the direct pressure gauge is too low, and the diesel engine does not make abnormal noise, The high pressure valve of the main oil passage and the pressure regulating valve on the primary oil filter can be debugged first, and the debugging effect is observed.

2. Internal inspection.

Inspection of oil unloading pan.

When the above-mentioned appearance inspection and debugging are invalid, drain the engine oil, dismantle the oil pan, and check whether there are Babbitt alloy falling off in the oil pan, especially massive falling off and other abnormal conditions; Check whether the filter screen of oil filter is blocked; Whether the welding parts of oil suction pipe and oil outlet pipe are blocked, and whether the end gaskets are firm and effective; Whether the solid seal of the oil pump cover is effective; Check whether the oil pump drive gear and oil pump shaft bushing are worn abnormally.

Inspection of pressure and leakage.

After the above-mentioned observation and inspection are considered to meet the requirements, the fault causing the low oil pressure has not been found. Generally, do not rush to dismantle or replace the relevant parts. According to the experience, compressed air can be connected to the main oil passage (a joint corresponding to the thread size of the main oil passage and a high-pressure hose connected with the air source), and the air pressure should be 0.4 ~ 0.5 MPa. Directly observe or touch the compressed air leakage degree at the clearance of the connecting rod bearing of the main bearing, and observe and analyze the following common abnormal situations of compressed air leakage:

(1) In the same kind of bearing, if the amount of compressed air leakage of a bearing is large and urgent, the Babbitt alloy will fall off or the bearing will be worn too much.

(2) If there is obvious air leakage at the oil pump shaft and bushing, it can be judged that the internal wear of the oil pump is too large.

(3) There is obvious air leakage in the oil return hole on the cylinder block side where the rotor filter is installed, which indicates that the rotor shaft is worn too much.

(4) There is air leakage in the inner side of the cylinder block where the primary oil filter is installed. Generally, the gasket of the primary oil filter assembly is damaged or reversed.

(5) If there is obvious air leakage in the timing gear chamber, it should be judged that the idler gear and shaft are not matched properly.

(6) If there is compressed air leakage in the main oil passage or other oil passages in the cylinder block, it can be judged that there are casting sand holes or cracks in the oil passage, especially in the new cylinder block.

(7) If necessary, remove the cylinder head cover at the same time and check the valve rocker mechanism for leakage. If there is uneven leakage, it means that the relevant parts are too loose (at this time, the crankshaft should be rotated).

If you want to know more, please contact Dingbo Power by email dingbo@dieselgeneratortech.com.