Example of agricultural machinery diesel engine
1、 Blue smoke emission:
The reason for blue smoke emission is that there is excessive oil burning in the combustion chamber. The causes and troubleshooting of this phenomenon are as follows:
(1) If the oil pan is overfilled, the excessive oil will splash onto the cylinder wall with the high-speed crankshaft and rush into the combustion chamber. The troubleshooting method is to stop the machine for about 10 minutes, check the oil dipstick and remove the excessive oil.
(2) The cylinder liner and piston ring components are severely worn and the clearance is too large. As a result, a large amount of oil will flow into the combustion chamber for combustion, accompanied by an increase in crankcase exhaust gas. The solution is to replace worn parts in time.
(3) The piston ring is inoperative. If the piston ring has insufficient elasticity, is stuck in the ring groove by carbon deposits, or the ring mouth is in the same line, or the oil return hole of the oil ring is blocked, the engine oil will enter the combustion chamber for combustion and emit blue smoke. The treatment method is to remove the piston ring, remove the carbon deposit, rearrange the ring buckle, and replace the components if necessary.
(4) Excessive valve and guide clearance. During air intake, a large amount of oil in the rocker arm chamber enters the combustion chamber and burns. The treatment method is to replace the worn valve and guide pipe in time.
(5) There are other reasons for blue smoke emission, such as too thin engine oil, too high engine oil pressure and poor engine running in, which will cause the engine oil to burn and emit blue smoke.
2、 Smoke exhaust and blackening:
This phenomenon is caused by incomplete fuel combustion. When black smoke is emitted, the engine power is often reduced, the exhaust temperature is too high, and the water temperature is too high, which leads to the wear of several parts of the engine and affects the service life of the engine. The causes and troubleshooting of this phenomenon are as follows:
(1) Insufficient air intake or blocked air intake pipe. In order to find out the cause, the following checks should be carried out: whether the air filter is blocked; Whether the air inlet pipe leaks; Whether the turbocharger is damaged.
(2) Improper adjustment of valve clearance and poor contact of valve sealing ring. Check the valve clearance, valve spring and valve sealing ring.
(3) The supply of each cylinder of the high-pressure oil pump is uneven or excessive. If the rotating speed is unstable and black smoke is emitted intermittently, it shall be adjusted to make it balanced or within the specified range.
(4) If the injection is too late, the injection advance angle should be adjusted.
(5) The fuel injector shall be removed for maintenance due to poor operation or damage.
(6) Cylinder liner and piston ring components are severely worn. In this case, the piston ring is not tightly sealed, and the air pressure in the cylinder drops, resulting in the diesel engine not fully burning and emitting black smoke, and the engine power drops sharply. In serious cases, the engine will automatically shut down under load. Wear parts should be replaced.
3、 Yellow smoke emission:
At the initial stage of startup and operation, yellow smoke is discharged at the medium speed stage. The yellow smoke is gradually reduced or disappeared after the temperature or load increases. It shows that the engine is easy to shut down at idle speed, the engine vibrates, the intake pipe "chokes", the exhaust pipe fires, the power is insufficient, and it is difficult to start. The causes and troubleshooting of this phenomenon are as follows:
(1) Individual intake and exhaust valves are not closed tightly, or the spring force of valve spring is insufficient, the valve push rod is bent, and the intake and exhaust valves are ablated. The solution is; Grind the valve, remove the carbon deposit, and replace the worn parts.
(2) The fit clearance between camshaft journal and seat hole is too large or the valve timing is out of alignment, most valves are ablated, and the cylinder liner and piston ring are worn too much. The treatment method is as follows:; Adjust the clearance and replace the worn parts.
