Design Of Digital Fuel Quantity Measurement Used On Test Bench Of Fuel Injection Pump Based On Needle Valve Lift

The measurement system in test bench of fuel injection pump have been introduced in this pape.The thesis analyses the problem of fuel measurement system of the test bench of fuel injection pump, and the experiments and designs are done according to the problem.This system includes hardware design and software design. The hardware includes sensors'selection, power supply circuit design and signal adjusting circuit design etc. The pressure sensor selects the sensor of good aseismatic performance and upper sensitivity, CYY-1 type pressure sensor, which may conquer adverse factors of big libration weak stability and improve sensitivity; rotate speed sensor selects MJKN8, in the former test bench of fuel injection pump, which can increase data veracity. This system also chooseπZDF type intangible element as the sensitive element of magnetism sense fuel injector, which is high performance SMR element, may measure the displacement condition about steal material untouchably. This system needs five electrical sources to offer electricity. If we design them separately, it will need high cost and use troublesomely. So we make several electrical sources together in an insulative board, which makes them compact in the frame and reduces their bulk, weight, the number of derivative line and jointing point, but also heightens the performance and dependability of circuit and debases cost. The signal adjusting circuit includes filtrate wave,magnify,debasing voltage, adjust the output singnal to 3V around,which makes the signal to satisfy the input request of single-chip computer.The software design uses the method of modularization and organization design, which lets program become convenience to amending and running alone. The main program modularizations include main program, display, program of rotation speed measurement, program of fuel measurement, program of display of quantity of fuel, program of pressure measurement, etc. thereinto, the main module includes initialization, which is controlled by program scanning to realize the control function for test system, other module are controlled by the main module. display module adopts serial port LCD display; program of rotation speed measurement fulfills test by taking count of pulse number.Program of display of quantity of fuel fulfills Magnetism sense fuel signal's wave shape voltage V and the time of injector oil, program of pressure measurement fulfills the judge of oil pressure's magnitude.The whole test system combines hardware and software, integrates Single Chip Microprocessor with sensor technique and realizes intelligent test of fuel measurement system of the test bench of fuel injection pump fast and truly under the control of the keyboard. This system has many advantages including low cost, handy operation, high presision,etc. It affords convenience to test power and oil consumption for repairing factory and farming machine management department.