The piston generator top clearance is too large. If the diesel engine is overhauled, the diesel engine piston top clearance is not checked and adjusted in strict accordance with the requirements, or the excessively thick diesel generator cylinder head gasket is selected to make the piston top clearance larger, which will increase the space of the diesel engine combustion chamber. This directly affects the compression ratio of the diesel generator and thus the cylinder pressure.
The piston generator top clearance is too large. If the overhaul is reduced due to the compression ratio of the diesel generator, the pressure and temperature of the diesel generator cylinder at the top dead center of the compression stroke are reduced, the fuel combustion conditions become worse, the fuel combustion is incomplete and insufficient, and the diesel generator is severe. Black smoke.
At this time, diesel generators may also have symptoms such as insufficient power, difficulty in starting (or failure to start), smoky white smoke after starting, and excessive fuel consumption.
To measure the piston head clearance of the diesel generator, you need to loosen the cylinder head bolts, remove the cylinder head, place the lead wire on the top of the piston, then install the cylinder head and tighten the diesel generator cylinder head bolts as required. After rotating the crankshaft at least one turn, loosen the cylinder head bolt again, and measure the thickness of the lead wire after removing the cylinder head. If the measured value is within the technical requirements, the diesel generator piston top clearance is correct. On the contrary, it means that the top clearance of the piston is wrong and needs to be adjusted (mainly according to the measured value to select the thickness of the cylinder head gasket).
Note: Ensuring the correct clearance of the piston top of the diesel generator is one of the important things that must be strictly done when assembling the diesel engine. When assembling a diesel generator, the piston generator top clearance must be adjusted within the tolerances required by the technical specifications. Under normal circumstances, as long as the installation is correct, the piston generator top clearance of the diesel generator will not change during use.
The main reasons for the insufficient compression pressure of diesel generator cylinders are as follows:
1. Diesel generator piston rings or cylinder liners are severely worn. The piston ring or cylinder liner of the diesel generator is seriously worn, which will make the cylinder of the diesel generator not tightly sealed, resulting in insufficient cylinder pressure of the diesel generator. Not only does it cause blue smoke from diesel generators to burn engine oil, but heavy loads will also cause serious black smoke.
When diesel generators are exposed to black smoke due to wear of piston rings of diesel generators, diesel generators will also have the following phenomena: diesel generators burn engine oil, engine oil consumption increases; diesel generators have insufficient power; diesel generators have low load idle speed Blue smoke is emitted when the load is heavy; blue smoke is emitted when the load is heavy; the diesel engine crankcase has a high exhaust pressure; the diesel generator is accelerated (the acceleration performance is too poor); the fuel consumption is increased; the diesel generator may be difficult to start.
Fault hazard: After the piston ring and cylinder liner of the diesel generator are worn, the cylinder pressure of the diesel generator is insufficient and the oil is on the combustion chamber, so that the normal ratio of the mixture of the mixture changes at the end of the compression stroke, so that the fuel is in an anaerobic condition. Under the burning, the combustion process is prone to coke formation, and the exhaust gas forms a large amount of black smoke.
2. The shape of the combustion chamber of the diesel generator changes. The shape of the combustion chamber of the diesel generator is degraded due to the manufacturing quality and long-term use, so that the piston generator top clearance is too large, too small, and the piston position is wrongly installed, which will change the shape and volume of the diesel generator combustion chamber, thus affecting the fuel. Mixing with air to deteriorate the fuel burning conditions.
3. The shape of the combustion chamber of the diesel generator changes. The shape of the combustion chamber of the diesel generator is degraded due to the manufacturing quality and long-term use, so that the piston generator top clearance is too large, too small, and the piston position is wrongly installed, which will change the shape and volume of the diesel generator combustion chamber, thus affecting the gas. The cylinder head gasket is damaged. After the phenomenon of ablation and flushing of the cylinder head gasket of the diesel generator, the cylinder pressure of the diesel generator is insufficient due to the tight seal. At this point, the diesel generator may emit white smoke, and the oil sump may increase the oil level due to the coolant. The quality of the oil mixed with air deteriorates the fuel burning conditions.