Trouble caused by too much oil in the combustion chamber of diesel engine      

1. too much oil

The 1 ZL50 loaders were inadvertently thrown over the road during the long distance transportation. Crane was lifted and the shell of the diesel engine side was damaged, and the rest remained intact. The driver's inspection found that the oil, diesel and coolant were lost in varying degrees, and then they were added with oil, diesel and coolant respectively. Start the engine, heard a heavy crash between starter gear and flywheel of the diesel engine, and observed at the start of the diesel engine fan blade only slightly turned they stopped and started again, fault phenomenon remains the same.

The analysis thinks, start the machine cannot drive the engine to rotate in the loader rollover, before loading machine is arranged in the trailer on the diesel engine technology is not normal, so the crank connecting rod mechanism, mechanism and gas supply system with fault. When the loader rollover, the oil sump of diesel engine is higher than the cylinder head position, and the I cylinder is higher than the cylinder. The diesel engine in this state, the oil sump oil will slowly from flowing into the combustion chamber of cylinder clearance. Because the position of the cylinder is the lowest, and the position of the cylinder is the highest, so the oil flow into the combustion chamber is probably the fifth cylinder, the fifth and the fourth cylinders, and the smallest one is the cylinder. It is very difficult to rotate the crankshaft flywheel with wrench, and the flywheel rotates back and forth very small angle, which indicates that the fault is caused by the internal resistance of the diesel engine. Remove the IV, V and VI cylinder valve chamber cover, with a flat screwdriver inserted into the cylinder VI inlet and exhaust valve gap, so that the VI cylinder inlet and exhaust valve has been in the open state. At this point, crank the flywheel with a wrench, and feel the crankshaft rotation angle is slightly larger than before.

In the same way, the V cylinder inlet and exhaust valve in the open state, when turning the crankshaft, the crankshaft rotation angle can feel some big; continue to make IV cylinder inlet and exhaust valve in the open state, rotate the crankshaft flywheel, the crankshaft can be rotated 360 degrees. This proves that the diesel engine oil sump through the cylinder clearance flow into the combustion chamber.

Because a large number of oil flows into the combustion chamber, when the crankshaft rotates, the compression ratio of the combustion chamber is too high and the crankshaft rotation resistance is too large during the piston ascending process, so the starter can not drive the diesel engine to rotate.

Find fault, decided to use 1mm feeler inserted IV, V and VI cylinder inlet and exhaust valve clearance, to replace the word screwdriver (for Flathead screwdriver too thick), so as to avoid excessive pressure valve and the piston top bad, but still can not start the test machine. The feeler thickness increased from 1 mm to 1.5 mm, once again start the engine can start smoothly, and a lot of oil discharged from the exhaust pipe. After the 2 cylinder feeler slide out from the valve clearance, the diesel engine was immediately suppressed flameout; re insert feeler, diesel engine start smoothly, and idle about 5 min. Estimation of combustion chamber oil has been drained, the cylinder and the cylinder V IV feeler have drawn, diesel engine can operate normally, and finally pulled out the VI cylinder feeler, diesel engine is still in normal operation, the fault has been ruled out.

2. too much diesel oil

1 TY220 bulldozer can not start fault during use. The fault phenomena are as follows: when the start switch to "ON" position, start the machine issued a "blah" sound (feel unable to start machine), no discharge of flue gas exhaust pipe, the fan does not rotate. The voltage, current and start relay check the battery is normal; remove the starter, with a crowbar to pry the flywheel ring gear, crankshaft to rotate, thereby excluding holding tile may; check the oil level increased, and diesel smell; closed start switch, PT pump on diesel tube (to disconnect, diesel cylinder head) self flow; connecting bolt loosening the exhaust manifold and cylinder head, diesel exudation.

The bulldozer is equipped with Cummins NT855 diesel engine with P T fuel pump. The fuel tank is located behind the cab and has a higher position. The flameout solenoid valve adopts a normally closed stop valve (power on, power off).

When the diesel engine is started, the stop valve is opened, the fuel passes through the oil inlet pipe, the fuel channel and the oil supply manifold in the cylinder head to the injector; when the flameout is stopped, the fuel can not enter the injector. If there are impurities in the diesel stuck in the sealing surface of the solenoid valve, or its valve deformation, a small amount of diesel will flow into a cylinder, thus forming a liquid lock (stuffy cylinder). It is considered that the failure of flameout solenoid valve is the cause of the above faults.

Troubleshooting methods are as follows: firstly, the dismantling of flameout solenoid valve, and the impurity of clean diesel cleaning valve on the refitted; secondly, with a crowbar to pry the flywheel ring gear, until the cylinder diesel exhaust; finally, the replacement of diesel engine, start the engine after the fault disappears. In order to avoid such failure, the operator must clean diesel oil, change the diesel filter cartridge according to the specified period, and regularly release the sediment from the fuel discharge valve under the fuel tank.