Characteristics of the phenomenon of diesel engine fuel timing ban:
1. Fuel supply time is too early. The diesel engine is difficult to start, and the crankshaft is prone to reverse rotation. There will be a clear knocking sound in the cylinder during operation, which may even cause premature wear of components, power drop, and poor idling. When judging, you can quickly increase the accelerator pedal from low speed to medium and high speed for an experiment. If the louder the accelerator pedal increases, the more serious the abnormal sound becomes, the sound weakens or disappears after the speed increases, and the sound disappears when the accelerator pedal is quickly released, and the sound recovers somewhat after the speed decreases, then it is the fuel supply time is too early;
2. Fuel supply time is too late. It easily causes the engine to overheat, the radiator boils, and the diesel consumption increases; the speed cannot increase sharply with the increase of the accelerator pedal, white smoke comes out of the exhaust, the economy and energy are poor, and the above phenomena can determine that the fuel supply time is too late.
Inspection of the fuel injection advance angle:
Remove the high-pressure oil pipe of the first cylinder of the fuel injection pump, move the engine decompression handle to the decompression position, and place the fuel injection pump at the maximum fuel supply position to eliminate the air in the pipeline of the diesel supply system and fill it with diesel. Rotate the crankshaft so that the piston of the first cylinder is at the top dead center of compression (both the intake and exhaust valves are closed). At this time, the scribe line on the flywheel or pulley should align with the mark on the body. Turn the crankshaft counterclockwise by an angle, which should be slightly greater than the fuel injection advance angle. Slowly and evenly rotate the crankshaft in the working direction while closely observing the oil level at the outlet valve seat. When the oil level just begins to fluctuate, it is the beginning time of fuel supply for the first cylinder, and the appropriate fuel injection advance angle can be determined from the scale indicated by the flywheel.
Adjustment of fuel timing:
Rotate the engine crankshaft so that the arrow on the flywheel housing points to the advance angle scale line on the edge of the flywheel. Regardless of the model type, observe whether the timing mark on the fuel injection pump is aligned. If it is aligned, the piston of the first cylinder is in the compression stroke; otherwise, it is in the compression stroke of the sixth cylinder piston, and the crankshaft should continue to be rotated. When adjusting the fuel timing, attention should be paid to the fuel timing mark and the coupling scale line. When the first cylinder starts to supply fuel, the scribe line mark on the coupling should align with the mark on the front cover of the fuel injection pump housing. If it exceeds the scribe line on the housing, it indicates that the fuel supply is too late, and the timing screw on the tappet should be unscrewed; if it has not reached the scribe line, it indicates that the fuel supply is too early, and the timing screw on the tappet should be screwed in. After adjusting the first cylinder plunger, adjust the fuel supply time of the other cylinders according to the fuel supply sequence of the fuel injection pump, taking the first cylinder as the standard. For example, if the fuel supply sequence is 1342, when adjusting the fuel supply time of the third cylinder, start from the moment the first cylinder begins to supply fuel, and turn 90 degrees on the dial. This is exactly the start time of fuel supply for the third cylinder, and the difference in fuel supply time between each cylinder must not exceed ±0.5 camshaft angles. Also, pay attention to the fuel timing marks. To facilitate the adjustment of the fuel injection advance angle, most diesel vehicles have fuel timing marks on both the engine and the fuel injection pump. Fuel timing marks can be divided into three types: one is the starting fuel supply mark of the first sub-pump of the fuel injection pump; two is the fuel injection advance mark on the engine flywheel shell and flywheel (in terms of crankshaft angle); three is the meshing mark of the transmission gear between the fuel injection pump and the engine, including the valve timing mark of the transmission gear and the connection mark between the fuel injection pump and the drive section.
Determination of whether the fuel timing is correct:
Whether the first cylinder is in the compression stroke can be judged by the following methods: One is to observe that both the intake and exhaust valves of the sixth cylinder are open, and the piston of the first cylinder is at the top dead center of compression; another method is to remove the side cover of the fuel injection pump and observe whether the plunger of the first cylinder has started to rise. Rising means it is about to inject fuel. After the engine is started, make minor adjustments to the fuel injection timing according to the situation. During operation, if the fuel timing is found to be inappropriate, loosen the fixing bolts on the coupling flange joint head, move the relative positions of the drive disc and the coupling. Turning the advance device clockwise (viewed from the front end of the engine) increases the fuel injection advance angle, otherwise it decreases, making appropriate adjustments, and finally tighten the fixing bolts again.
Since the working conditions of the valve head and valve seat friction pair are relatively harsh, to prevent the valve seat from becoming loose, the following points should be noted during use and maintenance:
① Maintain the normal temperature of the engine coolant during use, and prohibit the engine from overheating.
② Strictly prohibit cars from running overloaded or overspeed for a long time.
③ Do not immediately shut off the engine after running under heavy load, otherwise it will cause inconsistent cooling rates between the valve seat ring and the cylinder head, causing deformation of the seat ring, allowing high-temperature gas to leak, and resulting in the valve seat ring loosening.
④ During maintenance, if the seat ring needs to be replaced, try to select original factory parts, with appropriate interference fit, and the interference amount should be close to the upper limit. When assembling, place the seat ring in liquid nitrogen and cool it to -190°C (if no conditions, it can also be cooled in a refrigerator), then install it into the seat hole, and rivet all around firmly.
The content above is jointly released by the Official Website of Sanitation Garbage Truck (http://www.clwlu.com/)|www_clwlu_com and Garbage Truck Manufacturer (http://www.clwwcw.com/)|www_clwwcw_com. For more exciting content: Aerial Work Platform Model Number, put the vehicle gear into neutral. Whether it saves fuel depends entirely on you. Chemical Industry Vehicle Model Number