康明斯柴油發(fā)動機機油壓力突然過低的診斷與處理方法

　　在使用中機油壓力突然降低，機油表針突然指在零位，對于使用已久的發(fā)動機而言是維修中常見的故障之一。但機油壓力表針突然指零并不一定等于機油壓力突然降至零。

　　⑴原因

　　1）機油表及線路故障。

　　2）機油感應塞故障。

　　3）機油泵損壞。

　　4）凸輪軸軸承脫出泄漏機油。

　　5）噴油泵、增壓器、空壓機等潤滑油管破裂。

　　6）機油限壓閥卡在開啟位置，失去了調(diào)壓功能。

　　⑵診斷與處理方法

　　1）汽車在運行中，機油壓力突然降低，應立即停車檢查，防止因缺機油而發(fā)生燒軸、拉缸等重大事故。

　　2）先檢查發(fā)動機外部有無機油大量泄漏的痕跡，若有，說明機油管路、濾清器蓋等處有破裂或油底殼等放污螺塞松脫而漏油，應及時予以修復處理。

　　3）若外部并無大量機油泄漏的痕跡，則應檢查油機壓力表至感應塞的連線是否完好，表和感應塞是否良好。

　　4）抽出機油尺檢查機油量是否足夠。

　　5）松開發(fā)動機外部任一處機油管接頭，用起動機帶動曲軸轉(zhuǎn)動，查看供油情況，如果有機油流出，則應檢查機油限壓閥是否卡在開啟位置。

　　6）在曲軸轉(zhuǎn)動的同時，聽凸輪軸一側有無“叮當……”聲，有此聲，應進一步檢查凸輪軸軸承是否脫出，并予以及時排除。

　　發(fā)動機冷起動后或正常運轉(zhuǎn)時，出現(xiàn)機油壓力低于正常工作壓力。報警指示燈閃爍的現(xiàn)象時，一般屬機油系統(tǒng)故障，應停機處理。

　　⑴原因

　　1）機油牌號不合規(guī)定，粘度過低，使泵油壓力降低。

　　2）機油變質(zhì)或機油中有水。

　　3）機油容量不足。

　　4）發(fā)動機過熱，機油變稀，導致機油壓力過低。

　　5）機油集濾器堵塞，使機油吸入量減少而壓力過低。

　　6）機油粗濾器過臟，同時旁通閥損壞，使機油不易進入主油道。

　　7）機油泵磨損嚴重，齒輪嚙合間隙或泵蓋間隙過大，使泵油壓力下降。

　　8）限壓閥彈簧過軟，使主油道壓力低于規(guī)定值。

　　9）使用已久的發(fā)動機曲軸主軸承間隙和連桿軸承間隙過大，凸輪軸軸承間隙過大，導致機油壓力過低。

　　10）機油泵安全閥使用時間過長，閥與閥座磨損而產(chǎn)生不密封，或彈簧過軟，以致機油泵工作時，大量機油經(jīng)安全閥回流，使主油道難以建立起正常壓力而過低。

　　11）機油散熱器堵塞，同時旁通閥失靈，使機油壓力過低。

　　⑵診斷與處理方法

　　1）發(fā)動機在運行中發(fā)現(xiàn)機油壓力過低，應及時停車，約5min后檢查油底殼的機油平面是否低于規(guī)定值，若低于機油標尺的下刻線，應隨時添加同牌號的機油。

　　2）抽出機油尺，查看機油有無變質(zhì)和水分。如果機油變質(zhì)，應給予更換，并清洗機油道和濾清器芯；機油中有水分，應查明水的來源予以排除，并更換新機油。

　　3）由于季節(jié)變化時未及時換季使用合適粘度的機油，或誤加劣質(zhì)機油或不符合牌號等級的機油，均應及時換用適合季節(jié)粘度或牌號的機油。

　　4）在使用中如果發(fā)動機過熱，應考濾機油壓力的下降可能是機油因溫度過高而變稀所致。在此情況下，先使發(fā)動機溫度降低，待機油冷卻后再起動發(fā)動機，機油壓力便可正常。為此，在使用中應特別注意發(fā)動機的溫度和機油的散熱是否良好。

　　5）檢查機油濾清器芯是否清潔，旁通閥是否暢通。若濾芯達到更換周期或過臟應及時更換或清洗，并保證旁通閥無卡滯現(xiàn)象，活動自如。

　　6）檢查集濾器濾網(wǎng)是否過臟。長期未保養(yǎng)的集濾器，因膠質(zhì)較多，粘結在網(wǎng)罩上，嚴重影響機油的通過率而使供油壓力降低，對此應清洗保養(yǎng)。

　　7）檢查潤滑油道有無沉淀物堵塞，并在保養(yǎng)時予以疏通。

　　8）檢查限壓閥的彈簧是否過軟、閥門是否磨損過甚。若閥門磨損正常，則應檢查彈簧的彈力是否不足。可拆下彈簧，在試驗臺上檢驗，一般不允許隨意調(diào)整。若閥門磨損后不密封而漏油，應總體更換。

　　9）最后可檢查曲軸軸承、連桿軸承和凸輪軸軸承間隙是否過大，并給予修復。

Diagnosis and treatment of Cummins diesel engine oil pressure suddenly too low
Sudden drop in oil pressure in use, oil Biaozhen suddenly at zero, use has long been the engine is one of the common faults in maintenance. However, the oil pressure gauge suddenly to zero does not necessarily mean that the oil pressure suddenly dropped to zero.
⑴ reason
1) Oil table and line fault.
2) oil sensor plug failure.
3) damage to the oil pump.
4) camshaft bearings prolapse leak oil.
5) fuel injection pump, turbocharger, air compressor oil pipe rupture.
6) Oil pressure limiting valve stuck in the open position, lost regulator function.
⑵ diagnostic and treatment methods
1) the car is running, the oil pressure suddenly reduced, should immediately stop checks to prevent burning shaft, pull cylinder, such as a major accident occurs due to lack of oil.
2) a large number of first check engine with or without external oil leak traces, if any, Description oil pipeline rupture or oil pan and discharge sewage drain plug loose and oil spills filter cover, etc., should be repaired in a timely manner processing .
3) If the external no traces of a large number of oil leaks, you should check the oil-pressure gauge to the sensor plug connection is intact, tables and sensor plug is good.
4) pull out the oil dipstick check the adequacy of the amount of oil.
5) Release the engine external either an oil pipe joints, driven by the crankshaft rotation starter, to view the oil supply situation, if the oil outflow, you should check the oil pressure limiting valve is jammed in the open position.
6) while the crankshaft, listen to the camshaft side of the presence or absence of "jingle ..." sound, this sound should further check whether the camshaft bearing prolapse, and be immediately removed.

After starting the engine is cold or when the normal operation, the oil pressure below the normal working pressure. Flashing alarm indicator, is generally within the oil system failure, should stop treatment.
⑴ reason
1) oil grade irregularities, low viscosity, pump oil pressure decreases.
2) oil deterioration or oil, water.
3) the lack of oil capacity.
4) engine overheating, oil thinning, the oil pressure is too low.
5) The oil strainer clogging the oil suction reduced pressure is too low.
6) crude oil filter too dirty, the bypass valve is damaged, so that the oil is not easy to enter the main oil channel.
7) severe wear on the oil pump, gear meshing clearance or pump cover gap is too large, so that the pump oil pressure drops.
8) The pressure limiting valve spring is too soft, the main oil passage pressure below the specified value.
9) has long been used engine crankshaft main bearing clearance and connecting rod bearing clearance is too large, the camshaft bearing clearance is too large, resulting in low oil pressure.
10) the oil pump relief valve used for too long, the valve and valve seat wear generated is not sealed, or the spring is too soft, so that when the oil pump work, a large number of oil through the safety valve reflux is difficult to establish a normal pressure over the main oil path is low.
11) Oil radiator clogged, the bypass valve failure, the engine oil pressure is too low.
⑵ diagnostic and treatment methods
1) the engine is running, the oil pressure is too low, you should stop in time, about 5min after checking the oil sump plane below the specified value, below Dipstick engraved lines, with grades of oil should be added at any time.
2) draw out the oil dipstick to see whether the oil deterioration and moisture. If the oil deterioration, should be given a replacement, and cleaning the oil the Road and filter core; moisture in oil, you should identify the source of the water to be excluded, and replace the new oil.
3) As the seasons change is not timely seasonal use appropriate viscosity of the oil, or incorrectly added to poor quality oil or oil does not meet the grade level, should be timely switching engine oil viscosity or grades for the season.
4) use if the engine overheats, turned up the oil filter pressure decline may be oil due to high temperature due to thinning. In this case, the engine temperature, the standby oil cooling then start the engine, the engine oil pressure can be normal. To this end, in use, special attention should be the temperature of the engine and the oil of the heat dissipation is good.
5) Check the oil filter element is clean, the bypass valve is smooth. If the filter is reached replacement cycle or too dirty should be promptly replaced or cleaned, and ensure that the bypass valve sticking phenomenon freedom of movement.
6) Check the strainer filter is too dirty. Long-term maintenance strainer, glial more bonded network cast serious impact on the rate of oil through the oil pressure decreases, and this should be cleaning and maintenance.
7) Check the oil channel or without sediment clogging, and be in the maintenance dredge.
8) Check the pressure limiting valve spring is too soft the valve wear too much. If the valve is normal wear and tear, you should check whether the spring will lack. Can remove the spring, and the test on the test stand, and generally do not allow arbitrary adjustment. If the valve is worn seals and oil spills, overall replacement.
9) Finally, you can check the crankshaft bearings, rod bearings and camshaft bearing clearance is too large, and given to repair.