Combustion system in diesel engine smoke the cause of the problem of the identification and elimination method
(1) cylinder compression pressure is insufficient
The causes of insufficient cylinder compression pressure are: piston ring serious wear and tear (piston ring serious wear and tear will make the diesel engine
Blue smoke, this article do not make small narrative), the compression ratio (piston top clearance is too large or valve seat ring grooves into too deep) or valve seal no
A, the piston top clearance is too large
If the assembly of diesel engine, no strict inspection in accordance with the requirements and adjust the piston top clearance, or not at the time the piston top clearance adjustment
Slants big, directly affect the compression ratio of diesel engine, in turn, affects the cylinder compression pressure. Due to the compression ratio decreases, reduces the pressure of cylinder
Condensation pressure and temperature, make the fuel combustion conditions become worse, fuel burning incomplete, inadequate, diesel engine is a serious risk and black
Ensure that the right is assembly of diesel engine piston top clearance when must strictly to do one of the important events. In the assembly of diesel engine,
Piston top clearance adjustment must be within the scope of the technical specification requirements of tolerance. In general, as long as the correct installation, between the piston crown
Gap in the use process will not change.
B, valve seal is lax
Valve seal with serious deformation or wear, will cause the valve seal is lax, directly reduce the cylinder compression pressure and temperature, the combustion
Oil incomplete combustion, inadequate, resulting in serious diesel smoke.
C, valve seat ring concave into too deep
Valve seat ring long-term sustained strong impact, high temperature combustion and valve and valve seat ring aluminum alloy properties of bottom hole, will quickly
Seat sunken into the gradually increase, make the size of the valve between flat and cylinder head bottom relative increase, increase the capacity of the combustion chamber
Product and reduce the engine compression ratio, which reduces the cylinder compression pressure and temperature, leading to incomplete combustion fuel, no charge
Serious smoke points, diesel engine.
Cylinder compression pressure is insufficient, in addition to make diesel engine smoke, and the following phenomena:
Diesel engine work underpowered
Bad. Diesel engine to accelerate the weakness (acceleration)
Fuel consumption increase
If the diesel engine in the process of using the above-mentioned problem or phenomenon, you can use a dedicated measurement of steam cylinder pressure checklist
Cylinder compression pressure. Cylinder compression pressure measuring device is generally installed in the fuel injector hole, single cylinder testing, each cylinder. Then with the
Accurate value comparison, confirm whether too low.
Excluded methods: if the diesel engine cylinder compression pressure measurement and confirm the smoke is caused by cylinder compression pressure is low
, we must check the piston top clearance, valve seat ring concave depth and between valve and valve seat ring seal. The specific practices
. Loosen the cylinder head bolts, remove the cylinder head, on the top of the piston into the lead wire, and then loaded on cylinder head, tighten the screw cylinder head as required
Bolt, and then loosen the cylinder head bolts, remove the cylinder head after measuring the thickness of the galvanized iron wire, if measured values within the scope of the technical requirements, said
Piston top clearance correctly. On the other hand, shows the piston top clearance is wrong, need to be adjusted (mainly according to the measurement value of cylinder pad
The thickness of the).
. Remove the cylinder head, after careful observation and measure the distance between valve head plane and cylinder head bottom, if measured value is greater than the skill
Numerical technique requirements, the valve seat ring grooves into too deep, need to repair processing. The repair method is: replacement of valve seat ring and the
A valve to grind the valve. The specific requirements of the valve seat ring, please refer to the relevant technical requirements.
. If the valve seat ring concave depth unqualified, you should carefully check valve and valve seat ring between the sealing tape. The general situation
, after long-term use, the valve and valve seat ring between the sealing strip will have larger wear and deformation, the need for repair
The complex. Particular way is: grind the valve seat sealing tape, replace the valve and regrinding valve.
(2) the valve clearance is not correct
Valve clearance is not correct, the impact of diesel engine valve timing, also is the valve to open to open, the closing to shut down,
Directly affect the air inflow of diesel engine and reduce the excess air coefficient of diesel engine, diesel engine oil and gas mixture too thick, heavy fuel oil
Incomplete combustion, inadequate, diesel smoke.
Valve clearance is not correct in addition to make diesel engine smoke outside, still have the following phenomena:
Diesel engine power shortage
Diesel engine may be started difficult
May have a strong metal crash
Confirm the valve clearance correctly the basic method is: open the valve chamber cover, with a touch or feeler check valve clearance.
Method: according to the requirement to adjust the valve clearance.