Reasons for the damage of gasoline pump and maintenance methods
I. reasons for the damage of gasoline pump
the fuel delivery of EFI engine is absorbed by the pressure of the electric gasoline pump installed in the gasoline tank, and its motor part is also soaked in gasoline, which cools the high temperature generated during its work. In view of this working principle, it is easy to be damaged. The principle is as follows:
1. If the fuel lamp alarms for a long time, it is not refueled in time, Cause no gasoline to cool the motor, and burn the motor and the suction diaphragm
2. Dirty gasoline blocks the straw and diaphragm
3. The most critical point is that some car owners turn on the electric fire switch for a long time, the engine doesn't ignite, and sit in the car listening to the stereo and conversation. Because the circuit is connected and the gasoline pump starts to work, it can't release the pressure and burn the motor and diaphragm, causing the pressure to drop or burn to death. As far as I know, only domestic gasoline pump manufacturers with brands have reliable quality. If your oil pump is damaged many times, please check whether your habits are good first. 2、 Maintenance of gasoline pump
1. Maintenance of gasoline pump shell
(1) check the flatness error of the joint plane of the upper shell and the lower shell of the gasoline pump. Generally, the joint plane is placed against the flat plate and measured with a thickness gauge. The flatness error should not be greater than 0 10mm. If it is out of tolerance, it will cause air leakage and oil leakage, which will affect the oil output and pressure of the gasoline pump. Therefore, if the specified requirements are exceeded, the normal fine abrasive cloth can be placed on the flat plate for grinding
(2) the flatness error of the joint plane between the shell and the cylinder block shall not be greater than 0.20mm. The inspection and repair methods are the same as above
(3) check the axial clearance of the rocker arm on the rocker shaft, insert a feeler gauge between the rocker arm and the housing for measurement, and the clearance should not be greater than 0.80mm. If the specified requirements are exceeded, shims of the same thickness can be padded on both sides of the rocker arm
(4) the pressure of shell crack or lack of power will be larger and larger, so it should be replaced or bonded with epoxy resin adhesive. If the threaded hole on the shell is damaged, replace the shell or repair the screw hole
2. Maintenance of rocker arm
the plane where the rocker arm of the gasoline pump contacts the eccentric will shorten the working stroke of the diaphragm and reduce the amount of pump oil after wear. If the wear of rocker arm exceeds 0.2omm, surfacing shall be carried out. After welding, it shall be trimmed according to the template, and the surface roughness Ra value shall not be greater than 2.5 M
the radial clearance between rocker arm and rocker shaft shall not be greater than 0.1omm. There should be no clearance between the rocker arm shaft and the housing bearing hole. If the former exceeds the specified requirements or the latter has clearance, the hole can be enlarged and the rocker shaft with enlarged size can be replaced
3. Maintenance of oil inlet and outlet valves
due to wear or corrosion by acidic substances in gasoline, the oil inlet and outlet valves are deposited by colloids and other dirt, which makes them loosely closed, affecting the oil output and oil pressure. If the oil valve is damaged, it should be replaced
4. Inspection of diaphragm and diaphragm spring
the diaphragm is broken, hardened and deteriorated, and should be replaced. After long-term use, the elasticity of diaphragm spring decreases. Therefore, its free length and performance should be checked during engine overhaul. It is required that the diaphragm spring should have sufficient tension. If the tension is insufficient or corroded, it should be replaced with a new one
5. Performance test of gasoline pump
after the gasoline pump is installed, the performance test should be carried out, preferably on a special test bench. During the test, the installation dimension of the gasoline pump shall meet the actual installation requirements of the gasoline pump on the engine. When the eccentric wheel drives the gasoline pump at the specified speed, its technical requirements shall comply with the technical regulations. When the specified pressure is reached, stop pumping oil for 1min. Within this time, the pressure is mainly due to the decline of power lithium-ion battery and super capacitor force, which shall not be greater than 2.66kpa. In combination with PolyOne's quarterly earnings per share exceeding investors' expectations, there shall be no oil leakage within 3min
in the absence of a special test bench, the empirical test method can also be used: when the oil is sucked into the mouth, the tip of the tongue can be sucked; When blowing out the oil port, it cannot be blown, which means that the oil valve has good sealing. Immerse the oil inlet into water or gasoline, press the rocker arm by hand, and the oil outlet is fast and powerful without bubbles, indicating that the gasoline pump has good performance. Otherwise, replace the gasoline pump
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