康明斯发动机机油压力突然过低故障的诊断分析与处理方法

康明斯柴油发动机机油压力突然过低的诊断与处理方法

　　在使用中机油压力突然降低，机油表针突然指在零位，对于使用已久的发动机而言是维修中常见的故障之一。但机油压力表针突然指零并不一定等于机油压力突然降至零。

　　⑴原因

　　1）机油表及线路故障。

　　2）机油感应塞故障。

　　3）机油泵损坏。

　　4）凸轮轴轴承脱出泄漏机油。

　　5）喷油泵、增压器、空压机等润滑油管破裂。

　　6）机油限压阀卡在开启位置，失去了调压功能。

　　⑵诊断与处理方法

　　1）汽车在运行中，机油压力突然降低，应立即停车检查，防止因缺机油而发生烧轴、拉缸等重大事故。

　　2）先检查发动机外部有无机油大量泄漏的痕迹，若有，说明机油管路、滤清器盖等处有破裂或油底壳等放污螺塞松脱而漏油，应及时予以修复处理。

　　3）若外部并无大量机油泄漏的痕迹，则应检查油机压力表至感应塞的连线是否完好，表和感应塞是否良好。

　　4）抽出机油尺检查机油量是否足够。

　　5）松开发动机外部任一处机油管接头，用起动机带动曲轴转动，查看供油情况，如果有机油流出，则应检查机油限压阀是否卡在开启位置。

　　6）在曲轴转动的同时，听凸轮轴一侧有无“叮当……”声，有此声，应进一步检查凸轮轴轴承是否脱出，并予以及时排除。

　　发动机冷起动后或正常运转时，出现机油压力低于正常工作压力。报警指示灯闪烁的现象时，一般属机油系统故障，应停机处理。

　　⑴原因

　　1）机油牌号不合规定，粘度过低，使泵油压力降低。

　　2）机油变质或机油中有水。

　　3）机油容量不足。

　　4）发动机过热，机油变稀，导致机油压力过低。

　　5）机油集滤器堵塞，使机油吸入量减少而压力过低。

　　6）机油粗滤器过脏，同时旁通阀损坏，使机油不易进入主油道。

　　7）机油泵磨损严重，齿轮啮合间隙或泵盖间隙过大，使泵油压力下降。

　　8）限压阀弹簧过软，使主油道压力低于规定值。

　　9）使用已久的发动机曲轴主轴承间隙和连杆轴承间隙过大，凸轮轴轴承间隙过大，导致机油压力过低。

　　10）机油泵安全阀使用时间过长，阀与阀座磨损而产生不密封，或弹簧过软，以致机油泵工作时，大量机油经安全阀回流，使主油道难以建立起正常压力而过低。

　　11）机油散热器堵塞，同时旁通阀失灵，使机油压力过低。

　　⑵诊断与处理方法

　　1）发动机在运行中发现机油压力过低，应及时停车，约5min后检查油底壳的机油平面是否低于规定值，若低于机油标尺的下刻线，应随时添加同牌号的机油。

　　2）抽出机油尺，查看机油有无变质和水分。如果机油变质，应给予更换，并清洗机油道和滤清器芯；机油中有水分，应查明水的来源予以排除，并更换新机油。

　　3）由于季节变化时未及时换季使用合适粘度的机油，或误加劣质机油或不符合牌号等级的机油，均应及时换用适合季节粘度或牌号的机油。

　　4）在使用中如果发动机过热，应考滤机油压力的下降可能是机油因温度过高而变稀所致。在此情况下，先使发动机温度降低，待机油冷却后再起动发动机，机油压力便可正常。为此，在使用中应特别注意发动机的温度和机油的散热是否良好。

　　5）检查机油滤清器芯是否清洁，旁通阀是否畅通。若滤芯达到更换周期或过脏应及时更换或清洗，并保证旁通阀无卡滞现象，活动自如。

　　6）检查集滤器滤网是否过脏。长期未保养的集滤器，因胶质较多，粘结在网罩上，严重影响机油的通过率而使供油压力降低，对此应清洗保养。

　　7）检查润滑油道有无沉淀物堵塞，并在保养时予以疏通。

　　8）检查限压阀的弹簧是否过软、阀门是否磨损过甚。若阀门磨损正常，则应检查弹簧的弹力是否不足。可拆下弹簧，在试验台上检验，一般不允许随意调整。若阀门磨损后不密封而漏油，应总体更换。

　　9）最后可检查曲轴轴承、连杆轴承和凸轮轴轴承间隙是否过大，并给予修复。

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.