Abstract: This paper introduces the hardware circuit design and software program flow chart of measuring the speed and advance angle of injection pump with single-chip microcomputer with high accuracy. It has high reference value for similar system. Nanyang Polytechnic Xueqing Ji Wang Xi? Daqing Petrochemical Company Li Ning 1 Introduction Fuel injection advance angle refers to the engine in operation, the injector nozzle to the cylinder at the moment of injection (nozzle needle ascended the mark) to the piston line to the top dead center crank angle. Used in advance with the fuel supply angle instead. Due to wear and tear on the diesel fuel injection pump cam drive, the advance angle will change. In addition, the engine cylinder liner, piston wear or crankshaft, connecting rod in the boring or replacement, it will make the lead angle deviation from the normal combustion required value. Therefore, the engine is in use, fuel injection advance angle need to be checked or adjusted frequently. Accurate measurement of the value of advance angle is the key to accurate adjustment. This article describes the use of single-chip measurement of advance angle method, with high accuracy, wide range, simple features. 2 measurement principle In the test bed motor spindle and injection pump were fixed a photoelectric sensor, optical pulse by the photoelectric circuit into electrical pulses, respectively, with N1 and N2 said. 8051 MCU Timer / Counter 0 is set to work mode 2, which automatically reloads the initial value 8-bit timer / counter and sets the TMOD control bits GATE = 1 and TRO = 1 to enable the Timer / Counter 0 operation to be controlled by INT0. The spindle speed is calculated from the results of the measurement circuit shown in Figure 1. Figure 3 shows the advance time measurement circuit to measure the normal operation of the pump at a certain speed pulse N1 and pulse N2 difference T, calculate the advance angle. Since the absolute error of one revolution of the measurement spindle is only one reference pulse period (1 s), the relative measurement error of the rotation speed is small. (1) Spindle speed measurement The pump runs at a certain speed, the optical encoder pulse signal NO from measuring the spindle speed reaches P3.4 of 8051. The single-chip microcomputer detects the pulse signal of P3.4 pin and sets P1.0 pin to high level at the same time, D The next rising edge of the NO pulse triggers the rising edge of Q to a high Q output. INT0 causes the timer T0 to start operating. The number of interrupts is recorded by R0 and R1. The timer T0 is clocked for a period of time, t, Less than the interval between the two rising edges of the NO pulse), the time to request CPU will P1.0 feet low, the timer T0 continue to work, start recording time Δt, D flip-flop to wait for the next pulse of NO rising edge To, Q-side output low, INTO to make the timer T0 stop working. The CPU calculates the total time T between the rising edges of NO for two consecutive pulses, which is the time at which the spindle rotates one revolution so that the spindle speed is 1 / T. (2) advance angle measurement The pump runs at a certain speed, the optical encoder pulse signal NO from measuring the spindle speed reaches P3.4 of 8051. The single-chip microcomputer detects the pulse signal of P3.4 pin and sets P1.0 pin to high level at the same time, D The trigger rises to the next pulse (N1 pulse) at S, Q is high, and INT0? Causes timer T0 to start operating, recording the number of timer interrupts with R0, R1, and timer T0 for a period of time, t (This time should be less than NO, interval N1 between two rising edges of N1 pulse immediately). When it is time to request CPU to set P1.0 pin low, timer 0 continues to work and starts recording time Δt. D flip-flop to wait for the next S pulse rises, Q-terminal output low, INT0? Timer T0 to stop working. The CPU calculates the total time T (t + Δt), which is the advance time of NO over N1. In accordance with the method of measuring the rotational speed of the spindle to measure the time required A, and then use the formula: advanced = T / A to calculate the advance. 3 Measurement subroutine flow chart Given below is the spindle speed measurement subroutine flow chart, advanced angle measurement can refer to this flowchart. 4 Conclusion The method introduced in this paper has practical application in more than 30 oil pump test benches produced by two oil pump test rigs, which is accurate and fully meets the test requirements. The system of other systems speed and time of high-precision measurement of a certain reference value. 5 References [1] "Single-chip microcomputer principle and application" [M]. Ding Yuanjie editor Machinery Industry Press .1996,10 We supply DIY Soy Wax candle making kit for starters, professionals. And hand rolled honeycomb beeswax candle making kit for kids. Besides the classic DIY candle kit, we can custom any candle making supplies for you. 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[2] "Microcomputer Technology and Applications" [M]. Dai Mei calyx Shi Jiaquan Tsinghua University Press .1996,5