(1) high-pressure tubing size to be consistent Diesel engine fuel injection pump in the fuel supply process, due to the compressibility of diesel and high-pressure tubing flexibility, high pressure diesel will form pressure fluctuations in the pipe, pressure fluctuations in the transmission takes some time, Cylinder oil supply interval angle consistent, uniform fuel supply, high-pressure tubing length and diameter are selected after calculation, can not be arbitrarily changed. Therefore, multi-cylinder fuel injection pump calibration, you must ensure that the same high-pressure tubing diameter and length, the use of the following three points should also be noted. ①Diesel to be clean, before adding to the tank must be precipitated after 48h. Refueling to set up filters, and only use the upper diesel. ② The new high-pressure tubing to use diesel cleaning, anti-rust oil and dirt removal, if necessary, heating the tubing. ③ continuous working test rig, every 3 months should be a high-pressure tubing out of the oil test, the test bench can be used in the same standard injector, the same amount of tubing, the same single-cylinder piston pump or more Cylinder plunger pump in a sub-pump, followed by the high-pressure tubing for oil yield test. (2) The performance of using a standard injector Injector will seriously affect the fuel injection and fuel supply uniformity, even if the calibration of fuel injection pump to achieve the required oil and fuel supply uniformity, but actually far exceed The specified tolerance range (fuel injection allowable error within ± l%). Lead to changes in fuel injection has the following three factors: ①spray hole wear. Injector work, due to high pressure jet hole, high-speed flow of diesel fuel erosion and mechanical impurities in the fuel wear, jet hole diameter will be gradually increased, the amount of fuel injection increased. ② nozzle needle body guide surface wear. As the diesel fuel contained in the mechanical impurities into the gap between the needle valve body has played a role in abrasive so that the needle reciprocating needle movement in its guide surface scratches, the formation of subtle axial scratches. ③ nozzle opening pressure drop. As the injector pressure regulator spring preload changes, the needle sealing cone wear, needle and needle valve body parts of the poor sealing, will cause the nozzle opening pressure decreases, resulting in increased fuel supply and for Oil is not uniform. Therefore, when commissioning the injection pump, the test injector on the test site to be opened to the pressure with the standard injector opening pressure consistent or close to. When the fuel supply error of more than 4%, the fuel supply should be over-injected fuel injector singled out to recalibrate the opening pressure, the oil output is not very different, allows the use of open pressure to adjust the method of adjustment. (3) Strictly control the temperature of the test diesel oil As the viscosity and specific gravity of diesel oil all change with the change of temperature, and the fuel supply volume is calculated in units of volume, therefore, the test diesel temperature changes on the amount of fuel supply Adjustment has a great impact. For example, when the temperature is lowered, the viscosity of diesel oil increases, the fluidity decreases, the plunger leakage loss decreases, the fuel supply increases, especially the worn plunger is more obvious. To accurately adjust the fuel supply, laboratory temperature should be maintained at about 20 ℃. In accordance with the provisions of the fuel pump calibration oil temperature should be within the range of 40 ~ 45 ℃, this requirement can be installed through the injection pump test bed automatic oil temperature control device to be adjusted.
