RU2210084C2 - Meter measuring duration of spark discharges in spark-plugs - Google Patents

Abstract

FIELD: electric measurement technology, measurement of parameters of spark discharges in spark-plugs, measurement of duration of spark stage of discharge in semiconductor plugs of capacitive ignition systems of gas-turbine engines. SUBSTANCE: meter incorporates high-voltage voltage divider, limiter of signal amplitude, first, second and third discriminators, flip-flop, first and second front separators, clock pulse generator, logic OR gate, first and second logic AND gates, delay counter, master counter, digital arithmetic device, storage, unit controlling storage, decoder, digital indication unit. Output of high-voltage voltage divider is connected to input of limiter of signal amplitude, output of the latter is connected to inputs of first, second and third discriminators. Output of first discriminator is coupled to input of first front separator, output of the latter is connected to first input of OR gate. Output of second discriminator is connected to input of second front separator, output of the latter is coupled to second input of OR gate, output of the latter is connected to zeroing input of delay counter, first output of the latter is connected to one information input of digital arithmetic device. Output of third discriminator is connected to information input of flip-flop, to first input of first AND gate, clock pulse generator is connected to second input of AND gate, second output of delay counter is connected to third input. Enable input of digital arithmetic device and zeroing input of flip-flop are connected to second output of the latter. First input of second AND gate is connected to output of flip-flop, output of clock pulse generator is connected to second input of second AND gate. Output of second AND gate is connected to counting input of delay counter. Counting input of master counter is connected to output of first AND gate. One information input of digital arithmetic device is connected to output of master counter. Output of digital arithmetic device is connected to information input of storage, output of the latter is coupled to input of decoder which output is connected to digital indication unit. Unit controlling storage is connected to recording enabling input of storage. EFFECT: enhanced measurement accuracy. 2 dwg

Description

 The invention relates to electrical engineering, in particular to devices for measuring the parameters of spark discharges in spark plugs, and can be used to measure the duration of the spark stage of a discharge in semiconductor candles of capacitive ignition systems of gas turbine engines.

 The known time meter IV-3 (described in the following source: Time meter IV-3 8 g 2.746.0l8 RE UAKB "Lightning" Operation Manual), which is used to monitor the efficiency of ignition systems of gas turbine engines. The IV-3 meter is a pointer device and is designed to record the duration of the preparatory stage of a discharge in semiconductor spark plugs.

 The disadvantage of the meter is that it is inertial, like any pointer devices, and does not allow to fix with high accuracy the duration of the preparatory stage of each discharge in a series of discharges at a high repetition rate.

 A known meter for the duration of alternating current pulses (AS USSR 561152, class G 01 R 29/02, publ. 10.08.77.) Containing a counting pulse generator, a pulse counter, receiving coils, a filter, an amplifier, fixing circuits of the beginning of the first half-waves of the alternating filling signal and the moment of reaching the amplitude value of the first half-wave of the cutoff pulse, an electronic key, sensors of the beginning and end of the pulse, however, this device is not applicable in its functionality to measure the duration of the spark stage of a discharge in semiconductor candlelight.

 A device for measuring the duration of a spark (AS USSR 1442939, class G 01 R 29/02, publ. 07.12.88.), Comprising a current sensor, a rectifier, an amplifier, a level discriminator, two one-shot, two elements, OR, two inverter and counting unit, however, this device has insufficient measurement accuracy.

 The closest in technical essence and the achieved result to the claimed is a device for measuring the duration of the spark (AS USSR 1679416, CL G 01 R 29/02, publ. 23.09.91.), Containing a current sensor, a two-threshold level discriminator, peak a detector, a level discriminator, a single vibrator, an I element, a counting unit, the output of the current sensor being connected to the input of a two-threshold level discriminator, the output of which is connected to the input of the peak detector, the output of the latter is connected to the input of the level discriminator and to the input of the single vibrator, the output of the disc the level generator is connected to the first input of the And element, the second input of the And element is connected to the output of the one-shot, the output of the And element is connected to the input of the counting unit.

 The disadvantage of this device is that it has a low measurement accuracy and does not allow to measure the duration of each spark discharge in a series of discharges following each other with a certain frequency.

 The objective of the invention is to provide a device that allows you to measure with high accuracy in digital form the duration of the spark stage of each discharge pulse in a series of discharges in semiconductor candles of capacitive ignition systems by using a voltage drop sensor in the candle - a high voltage voltage divider, as well as by using the digital method of forming delays.

 The problem is solved in that in the spark duration meter containing the first logical element And, the first discriminator, in contrast to the prototype, an additional high-voltage voltage divider, a second and third discriminators, a signal amplitude limiter, a trigger, first and second fronts, a clock generator are introduced (GTI), OR logic element, second AND logic element, delay counter, main counter, digital arithmetic device, memory unit, memory control unit, decoder, qi unit In this case, the output of the high-voltage voltage divider is connected to the input of the signal amplitude limiter, the output of the latter is connected to the inputs of the three discriminators, the output of the first discriminator is connected to the input of the first fritter, the output of the latter is connected to the first input of the OR element, the output of the second discriminator is connected to the input of the second edge selector, the output of the latter is connected to the second input of the OR element, the output of the latter is connected to the zeroing input of the delay counter, the first output of the last connection with the input of the digital arithmetic device, the output of the third discriminator is connected to the information input of the trigger, with the first input of the first AND element, the GTI is connected to the second input of the last, the second output of the delay counter is connected to the third, the resetting trigger input is also connected to the second output of the last the first input of the second element And is connected, the GTI output is connected to the second input of the last, the output of the second element And is connected to the counting input of the delay counter, the counting is connected to the output of the first element th input of the main counter, one of the information inputs of a digital arithmetic device is connected to the output of the last one, the output of the last one is connected to the information input of the memory unit, the output of the last one is connected to the decoder input, the output of the last one is connected to the digital display unit, the control unit is connected to the recording permission input of the memory unit memory.

 Improving the measurement accuracy is ensured by the fact that in the signal taken from the sensor of the voltage drop in the candle - the high voltage voltage divider, the steepness of the edges and drops of the signal during the spark stage and when the preparatory stage of the discharge goes into the spark is incomparably greater than in the discharge current signal ( the waveform of the discharge current and voltage drop in the candle during a spark discharge in a semiconductor candle is given in A.S. USSR 1804211, class G 01 R 31/30, registered 09.10.92), as well as through the use of the digital method of forming Hovhan delay.

 Figure 1 shows the structural diagram of the inventive device.

 Figure 2 shows the timing diagrams of the operation of the claimed device.

 The device comprises a high-voltage voltage divider 1, a signal amplitude limiter 2, first, second and third discriminators 3, 4, 5, trigger 6, first and second edge detectors 7, 8, a clock generator (GTI) 9, a logic element OR 10, the first and the second logic elements And 11, 12, delay counter 13, main counter 14, digital arithmetic device 15, memory unit 16, memory control unit 17, decoder 18, digital display unit 19, while the output of the high voltage voltage divider 1 is connected to the input of the limiter amplitude Ignala 2, the output of the latter is connected to the inputs of the first, second and third discriminators 3, 4 and 5, the output of the first discriminator 3 is connected to the input of the first highlighter 7, the output of the latter is connected to the first input of the OR element 10, the output of the second discriminator 4 is connected to the input of the second edge selector 8, the output of the latter is connected to the second input of the OR element 10, the output of the latter is connected to the zeroing input of the delay counter 13, the first output of the latter is connected to one of the information inputs of the digital arithmetic device 1 5, the output of the third discriminator 5 is connected to the information input of the trigger 6, with the first input of the first element And 11, the GTI 9 is connected to the second input of the last, the second output of the delay counter 13 is connected to the third, the resolution input of the digital arithmetic device is also connected to the second output of the last and resetting the trigger input 6, the first input of the second And 12 element is connected to the output of the last, the GTI 9 output is connected to the second input of the last, the output of the second And 12 element is connected to the counting input of the delay counter 13, to the output of the first electronic And 11, the counting input of the main counter 14 is connected, one of the information inputs of the digital arithmetic device 15 is connected to the output of the last, the output of the last is connected to the information input of the memory unit 16, the output of the last is connected to the input of the decoder 19, the output of the last is connected to the digital display unit 18, to the recording permission input of the memory unit 16 is connected to the memory control unit 17.

The signal proportional to the voltage drop in the candle, coming from the high-voltage voltage divider 1 (Fig.2, a), is limited in amplitude and fed to the inputs of the first, second and third discriminators 3, 4, and 5. The third discriminator 5 captures the moment of transition of the preparatory stage a discharge spark, its discrimination threshold U _nop1 set below the level corresponding to the voltage in the spark during the preparatory stage of the discharge (2, as indicated by t _nc), but higher than the amplitude value at the time of spark discharge step and U _m (spark discharge step is indicated in FIG. 2, t and _u). The first and second discriminators 3 and 4 fix respectively the positive and negative half-waves of voltage in the candle during the discharge. The output signals of the first and second discriminators 3 and 4 are shown in figure 2, c, d. The output signal of the third discriminator 5 is shown in figure 2, b. Logical signal "1", coming from the third discriminator 5, allows the input of clock pulses from the GTI 9 to the counting input of the main counter 14 through the first logical element And 11. The delay counter 13 is entered to accurately record the moment of the end of the spark discharge stage. It is reset by the front of each half-wave of the voltage drop signal on the candle (Fig. 2, a): the signals from the outputs of the first and second discriminators 3 and 4, passing through the first and second highlighters 7 and 8 and the logic element OR 10, are fed to the counter zeroing . At the end of the spark stage, the reset signals cease to arrive at the indicated input of the counter and the counter will count off the set delay, which should be known to be longer than the duration of the discharge half-cycle. The signal for the end of the delay from the output of the counter 13 through the first logical element And 11 stops the count in the main counter 14. The logical signal at the counting input of the main counter 14 is shown in Fig.2, e. The trigger 6 provides a lock on the counter delay 13, and through it the arithmetic device 15, during the intervals between the digits. It is set by the front of the signal from the third discriminator 5 (at the moment of the transition of the preparatory stage of the discharge to spark) and is reset by the signal of the end of the delay from the delay counter 13. The logical signal from the output of trigger 6 is shown in Fig. 2, e. The logic signal "1" from the output of trigger 6 allows the input of clock pulses from the GTI 9 to the counting input of the delay counter 13 through the second logic element And 12. The digital arithmetic device 15 calculates the difference of the digital codes from the main counter 14 and the delay counter 13. As a digital arithmetic devices can be used adder chips. The permission signal for its operation comes from the delay counter at the time the delay ends.

 Since the repetition rate of discharge pulses in semiconductor candles can vary between 1 ... 50 pulses / s, a digital indication of the measurement result of each signal makes it impossible to perceive the meter readings. Therefore, the meter uses a memory control unit 17, which allows the recording of information from a digital arithmetic device to the memory unit 16 at certain time intervals after 1..3 s, regardless of the frequency of the discharge of discharges in the candle. The decoder 19 decodes the digital code of the measurement result in the code of seven-segment indicators of the digital display unit 18.

 So, the claimed invention allows to measure with high accuracy the duration of the spark stage of each discharge in semiconductor spark plugs at a high repetition rate of discharge pulses and thus expands the possibilities and quality of evaluating the effectiveness of ignition systems.

Claims (1)

 A spark-discharge duration meter in spark plugs containing the first logical element And, the first discriminator, characterized in that it additionally introduces a high-voltage voltage divider, second and third discriminators, a signal amplitude limiter, a trigger, first and second fronts, a clock generator (GTI) , OR gate, second AND gate, delay counter, main counter, digital arithmetic device that calculates the difference of digital codes from the main counter and counter delays, memory unit, memory control unit, decoder, digital display unit, while the output of the high-voltage voltage divider is connected to the input of the signal amplitude limiter, the output of the latter is connected to the inputs of three discriminators, the output of the first discriminator is connected to the input of the first fritter, the output of the latter is connected with the first input of the OR element, the output of the second discriminator is connected to the input of the second highlighter, the output of the last is connected to the second input of the OR element, the output of the last is connected to to the waning input of the delay counter, the first output of the last is connected to the input of the digital arithmetic device, the output of the third discriminator is connected to the information input of the trigger, with the first input of the first element And, to the second input of the last connected GTI, to the third input of the first element And the second output of the delay counter, the zeroing input of the trigger is also connected to the second output of the last, the first input of the second element And is connected to the output of the last, the GTI output is connected to the second input of the last, the output of the second That And is connected to the counting input of the delay counter, to the output of the first element And the counting input of the main counter is connected, one of the information inputs of the digital arithmetic device is connected to the output of the last, the output of the last is connected to the information input of the memory unit, the output of the last is connected to the input of the decoder, the output of the last connected to the digital display unit, a memory control unit is connected to the recording permission input of the memory unit.

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