The direction of the fuel pump system control valves, safety relief valve is to prevent excessive oil pressure oil pipeline, which is the role of one-way valve in the fuel pump stops working, maintain a pipeline of fuel oil pressure, so that the oil supply prompt and easy to start the engine again starting.
In order to improve the reliability of products, ensure the normal operation of equipment, must be correctly detect whether the valve failure. Long-term since, the traditional method for detection of valve opening and closing characteristics has been used in the sixty or seventy's -- by oil testing, and testing process is mainly by manual operation. The traditional method of simulation of fuel pump working condition, need in the oil pipeline filled with oil, and then a few days to observe the oil check valve leakage. Complex structure of this detection system, it is difficult to meet the production automation. And its low precision, large amount of manual work, low test efficiency, and finished product testing, it is difficult to restore completely clean.
With the rapid development of computer technology, the use of computer technology used in hydraulic testing technology has demonstrated the superiority of high test accuracy, test speed and greatly reduces the workload of manual. Not long ago, the author designs a set of fuel pump valve opening and closing characteristics of online detection system, detection using gas instead of oil, not only to solve the previous problems, but also can correctly grasp the valve performance and condition.
Of fuel pump valve
In any condition, the fuel pump to the engine supply system must provide the required amount of fuel. Fuel pump fuel continuous suction from the tank, through fuel filter, fuel distributor, sent to the solenoid in the injector. Fuel injector to the precise amount of oil injected into the engine inlet. The excess fuel to the tank through the pressure regulator.
Fuel pump check valve used to prevent backflow of fuel, maintain residual pressure pipe, so that the next likely start the engine, and can prevent the oil and gas resistance high temperature generated by the phenomenon, affecting the engine hot start performance. The one-way valve performance requirements are: when the oil flow through the check valve, resistance to be small, also is the pressure loss should be small; and when the reverse flow of oil, the valve port sealing better, no leakage; work should not have vibration, shock and noise.
When the pump output pressure exceeds the rated value, the safety relief valve will automatically open, into the oil chamber high pressure fuel may be returned to the oil pump, and in the circulating pump and motor, in order to avoid congestion caused by the oil pipeline oil pressure is too high cause pipe rupture or damage to the fuel pump and other phenomena. So the relief valve main performance requirements are: voltage range, voltage deviation is small, pressure runout small, sensitive action, flow capacity, small pressure loss and low noise.
In the valve spring stiffness and pre-compression is constant, the maximum relief valve from opening to opening, and the maximum opening to the relationship between flow and pressure in the closed process, known as the relief valve opening and closing characteristics. Its dynamic performance is the mutation than when the system pressure relief valve set pressure, valve of the pressure change and stabilization. General pressure overshoot, rise time and duration to measure. The fuel pump Zhejiang Yuhuan automobile fittings factory as object, see the work of the fuel valve.
In the operating voltage of 12V, the rated flow rate Q=1L/min, burst pressure p=0.45Mpa~0.63Mpa.
In the work process, one-way valve opening of liquidity is better, can make the pipeline fluid circulation, and the sealing requirements of high, if one-way valve leakage than the required value, not enough remaining oil pipeline, will directly affect the next launch vehicle. Relief valve leakage is a comprehensive performance index, which reflects the manufacturer's manufacturing process and assembly level, has a significant influence on the size of the static and dynamic performance of the relief valve. Relief valve opening pressure and closing pressure decreases with its increase in leakage, to open and close characteristics variation.
Design of test system for worktable
The principle of testing system
In part by the detection system with the oil port cover (workpiece), 5 solenoid valve, a vacuum generator, a gas sensor composed of triple pieces control.
Workpiece is positioned and sealed in good condition, from the bottom of the workpiece by electric pressure relief valve, to achieve a given pressure, safety relief valve open, the pressure is maintained, computer automatic timing, sealing pressure relief valve in the process of judgment. Holding pressure after the end of the electromagnetic valve, computer control of the 1 pressure, check valve open. The next test is to use vacuum sealing check valve, change the traditional methods, the detection of gas instead of oil.
Design of test system for work machine parts
Including the design of testing system: the mechanical fixture design table, gas detection system design and system control circuit design. This paper introduces the mechanical fixture design table. The author studies the core to the fuel pump Zhejiang Taizhou Yuhuan automobile accessories factory, research the valve opening and closing characteristics of on-line test system based on.
Work station design reasonable, has the following key issues in need of special attention:
(1) the location of workpiece.
(2) the selection of the cylinder. After the workpiece by cylinder compression, and then to the workpiece pass is pressure tested. Calculated pressing force so be required on the workpiece, to meet the requirements of test equipment. Cylinder selected, we can stand on the support cylinder design, determine the geometry and calculate the strength and reliability of computing, improve the safety and reliability of online detection system.
(3) the design of all aspects of the sealing problem.
Intelligent test system
Most valve manufacturers are still in use of artificial methods of testing the use of oil, this method is of low efficiency, big error, and can only be made on the static performance tests, dynamic tests are often incapable of action. Modern industry and science and technology not only the static performance of the components of the request is very high, and a direct impact on the dynamic characteristics of product precision is also put forward higher and higher requirements. System only with high-speed A/D conversion to device testing system and high precision computer in static characteristics prescribed accuracy measured components, only the computer testing system can be more accurately measured components of the dynamic performance, and the analysis and processing, get information about the performance characterization of components from which, and provide the basis for the product design. Compared with the manual test methods, the advantages of computer-aided test of its powerful data processing function, high test precision, can guarantee the real-time measurement, to prevent human error, compensation of nonlinear sensor, realize the whole testing process intelligent control, strict control of experimental conditions, and increase test efficiency.
Test system control chart, it includes: computer, used for receiving the digital signal output from computer instruction and to relay module output analog signal instructions I/O converter, amplifier module for receiving analog signal and digital signal output to the computer, the A/D converter for receiving analog signals and to the cylinder output control signal, relay module for receiving the pressure sensor output analog signal and the signal conditioning amplifier module, is used to detect the fuel pump check valve of the pressure sensor, and is used to control the gas path of each electromagnetic valve.
The A/D converter, I/O converter is installed in the computer interface card, the computer interface card installed in the mainframe computer, the computer interface card through the computer's ISA interface and computer connections; relay module, amplifier module, a negative pressure sensor supply voltage source are mounted on a board.
In a signal, the pressure sensor module through the analog signal amplifier, and then by the I/O converter into a digital signal that we need through the computer display. We use the computer, through the D/A conversion signal to control the various gas path in the electromagnetic valve, to achieve detection completely intelligent.
Conclusion
When in normal work, the one-way valve working pressure is lower than the rated working pressure of the one-way valve, check valve opening pressure to meet the system requirements as low as possible under the circumstances, to reduce the pressure loss. The overflow valve setting pressure shall not exceed the maximum hydraulic system pressure, relief valve of the maximum flow rate to within its rated flow. Through trial and practical circuit analysis shows that, the test system is reliable, with high precision and speed and strong data processing ability.
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