SU964510A1 - Internal combustion engine phase characteristics measuring device - Google Patents

Description

54) OASOBtlX METER OF INTERNAL COMBUSTION ENGINE CHARACTERISTICS

The invention relates to means for diagnosing the testing of internal combustion engines, primarily those that serve to determine the phase moments of reaching certain parameters of the work process.

Phase characteristics of the internal combustion engine are known, comprising an upper dead center sensor, a frequency divider, a D-flip-flop and an adder connected in series, an amplifier process sensor, and a frequency meter, the output of the divider also being connected to the adder.

The known devices determine the phase characteristics of the processes having a clearly defined onset, for example, the ignition advance angle and the injection advance angle 1.

A disadvantage of the known devices is the low accuracy of the determination of the phase characteristics of the processes that do not have a well-marked front of the process start signal, for example, the phase of achieving the maximum combustion pressure.

The purpose of the invention is to improve the accuracy of determining the phase characteristics of various processes.

The goal is achieved by the fact that the meter contains a differentiator, a filter and a Schmitt trigger, connected in series and connected between the amplifier and the O-trigger input, as well as a valve connected between the adder and the frequency meter, the output of which is connected to the valve inlet.

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FIG. 1 shows a diagram of a meter, for example, the angle corresponding to the maximum combustion pressure; in FIG. 2 - diagrams, according to his work.

15

The proposed meter contains a sensor 1, for example, pressure, an upper dead center sensor 2 and an electrical maximum pressure indicator 3 interconnected, a time selector 4 and a frequency meter 5. The maximum pressure indicator 3 contains an amplifier b connected in series, a differentiator 7, a filter 8 and trigger 9 Schmitt. The input of the amplifier b is a 25 connection with the pressure sensor 1.

The time selector 4 contains a frequency divider 10 connected in series, associated with it via the D input O-flip-flop 11, connected by one

30, an adder 12 modulo two and a valve 13 connected to it with one input, the second input of which is connected to the output of the reference frequency of the frequency meter 5, and the output from the counting input of the frequency meter 5. Moreover, the upper dead center sensor 2 is connected to the input of the amplifier 10 frequency, and the output of the Schmitt trigger 9 to the D input of the 0-flip-flop 11. The operation of the angle meter corresponding to the maximum combustion pressure is as follows. The signal from pressure sensor 1 is fed to the input of pressure maximum indicator 3, where a signal corresponding to maximum combustion pressure is generated. The signal of the upper dead center sensor 2 is fed to the input of the time selector 4, which allocates the time interval between the top dead center and the moment the maximum pressure is reached. These time intervals are separated at each duty cycle and filled with impulses of the reference frequency and read out by the frequency meter 5. The operation of the pressure maximum indicator 3 is based on the properties of the pressure rise rate function obtained by differentiating the signal of the pressure sensor 1 supplied through the amplifier b to the input of the differentiator 7. When the pressure reaches the maximum value, the function of the growth rate is equal to the Kull. Therefore, the signal obtained at the output of differential 7 is proportional. The increase in pressure through the filter 8, which cuts off high-frequency noise, is fed to the input of a Schmitt trigger, which forms a rectangular pulse from this signal, the front of which corresponds to the maximum combustion pressure. The time selector 4 forms the time interval between the top dead center and the front of the square pulse at the Schmitt trigger 9. In order to improve the noise immunity, the D-trigger 11 is used for the time selector, the Admittance of the Schmitt trigger 9 and the input A D-signal from the frequency divider 10, the input of which is supplied by the signals of the sensor 2 of top dead center. For a four-stroke engine, frequency divider 10 should have a four-way division factor, and for a two-stroke engine, two. Since the voltage level at the OC input of the trigger 11 is changed by the signals of the upper dead point sensor 2 as a result of dividing by the Divider 10 before the pulse arrives at its C input, the information at the output of the trigger 11 is reversed by the arrival of each. impulse with trigger 9 Schmitt. Separation of the time interval corresponding to the angle of rotation of the knee shaft from the top dead center until the maximum combustion pressure is reached by modulator two adder 12, the output of which produces a positive polarity pulse when the logical levels change at the O input and the D trigger. 11, where you connect the 1S inputs of the adder. Thus, one input of the valve 13 receives impulses with the sum of .tor 12 modulo two, duration. 12, and to the other input - pulses of the reference frequency f0 from the output of the frequency meter 5. As a result, at the output of the valve 13, pulse packets are formed, the number of which in each packet The packets follow with the frequency f „following duty cycles and arrive at the counting input of the frequency meter 5 operating in frequency measurement mode. In this case, in the frequency meter 5, a time interval is formed during which the measurement is conducted. The result of the measurement is represented on the digital indicator of the frequency meter 5 as the number N Since the angle of rotation of the crankshaft H from the top dead center until the maximum pressure is reached and the time interval, corresponding to it, is related by the dependence. about / min,. p f 157,; i 1 for 2 stroke dvuhatb I 2 for four stroke. I. If you choose rfo 360 for a push-pull dvkgatel, and for three-stroke TF-720, the readings of the N frequency meter correspond to the angle of rotation of the shaft g 1l do not require recalculation. The measurement result can be printed using a digitizer connected to the frequency meter.

Claims (1)

Invention Formula A phase response meter for an internal combustion engine comprising an upper dead center sensor, a frequency divider, a D-trigger and an adder connected in series, an amplifier process process and a frequency meter, the output of the divider also being associated with increase the accuracy, the meter contains a differentiator, a filter and a Mmitt trigger, connected in series and included: between the amplifier and the D-flip-flop input, as well as a valve connected between the adder and the frequency meter, the output of which is associated with valve inlet. Sources of information taken into account in the examination 1. USSR author's certificate 9 265514, cl. G 01 M 15/00, 1968. ig. f -G IG