Excavator smoke is big? Insufficient engine power? What went wrong? In theory, the exhaust smoke of the engine is that the fuel injected into the cylinder cannot be completely burned. At this time, if the power is not reduced, it may be that the fuel supply set by the oil pump is too large. So what checks should we perform on the excavator?
Perform the following inspections:
1. Air filter: When the air filter is too dirty, it will cause insufficient air intake. At this time, the serious smoke exhaust must be accompanied by an alarm (when there is this device). The simple inspection method is to remove the air filter and test run.
2. Turbocharger: When the engine still hasn't improved after removing the air filter, check the turbocharger. The standard method is to measure the air pressure supplied by the turbocharger to the engine. In fact, most of them check the mechanical state of the turbocharger: that is to say, the core of the turbocharger does not have radial axial slack, flexible rotation, and no bore sweep is normal.
3. Cylinder break: When the turbocharger is normal, the fault of intake air can be eliminated. At this time, the method of cylinder break can be used to determine the working status of each cylinder. Put the engine speed at idle speed (or the lowest speed), use a wrench to disconnect the high-pressure fuel pipes of each cylinder in turn, and compare the sound of the engine after disconnecting the high-pressure fuel pipe. When a cylinder disconnects the high-pressure fuel pipe, the sound of the engine ( This refers to the working sound of the engine, not the knocking sound caused by mechanical problems) If there is no obvious change, this cylinder can be considered as not working or working poorly. At this time, the corresponding fuel injection body is removed, the fuel injection body is externally connected to the machine body, and then the engine is started, and the atomization of the fuel injection body is observed.
4. Down exhaust: There is very little down exhaust during normal engine operation. When the current exhaust is obviously too large, it may be that the cylinder, piston, and piston ring are seriously worn or the piston ring is split or broken. It will also cause insufficient power to exhaust smoke. For severely exhausted engines, dismantle and repair.
5. Cylinder pressure: For the lower exhaust, the cylinder pressure test is required. Install the pressure gauge into the cylinder to be measured and start the engine to measure the cylinder pressure. Various engines have different requirements for standard cylinder pressure, but they are generally around 3MPa (30kg / cm2). At the same time, the fuel injection body can be reversed to observe the situation of the fuel injection mist. If it is not atomized or the atomization is poor, the fuel injection head may be considered damaged.
Check if the valve clearance is within the standard range, if not, it needs to be adjusted, if it is in the standard, it may be a valve problem, and the engine should be disassembled and checked. Adjustment method of valve clearance (take 6-cylinder engine, ignition sequence 1-5-3-6-2-4 as an example): Turn the engine to the top dead center of 1 cylinder compression (start exhaust of 6 cylinder exhaust), check 1 , 2,4 cylinder intake valve and 1,3,5 cylinder exhaust valve. Then turn the engine to the top dead center of 6 cylinder (1 cylinder exhaust ends the intake start), check the other valves.
7. The timing (fuel supply time, fuel advance angle, ignition time) varies for different engines. The abnormal ignition time will cause insufficient engine power and high temperature. The method of checking the ignition time of the diesel engine is ( Take the 6-cylinder engine and ignition sequence 1-5-3-6-2-4 as an example): A. Remove the 1-cylinder high-pressure fuel pipe and remove the oil outlet valve core and spring, and then press the oil outlet valve seat tightly on the oil pump . B. I pressurize the oil pump and turn the engine at the same time. When the oil outlet does not output oil, it is the start position of the fuel supply opening. At this time, the scale value on the belt pulley (some engines are on the flywheel) corresponds to the body. The indicator of this scale is the fuel supply advance angle. After comparing with the standard value, adjust accordingly. The engine is the source of power for construction machinery and equipment. Checking the engine will not only make the equipment more powerful, but also extend the service life of the engine.
