RU2179322C1 - Meter of residual voltage across reservoir capacitor in capacitive ignition systems - Google Patents

Abstract

FIELD: electric measurement technology. SUBSTANCE: invention specifically refers to devices measuring parameters of spark discharges in sparking plugs and can be used to measure residual voltage across reservoir capacitor in capacitive ignition systems of gas-turbine engines. Meter incorporates current pickup, voltage divider, limiter of signal amplitude, double threshold comparator, circuit of match delay, first univibrator, second univibrator, retrieval and storage unit, analog-to-digital converter, timer, register-catch, decoder and indicator. Current pickup is connected to input of limiter of signal amplitude, output of the latter is linked to input of double threshold comparator whose output is connected to input of circuit of match delay, output of the latter is connected in its turn to inputs of univibrators, control input of retrieval and storage unit. Output of first univibrator is connected to trigger input of analog-to- digital converter. Output of second univibrator is connected to control input of retrieval and storage unit, voltage divider is linked to information input of retrieval and storage unit, output of the latter is connected to analog-to-digital converter, register-catch, decoder and indicator connected in series. Timer is coupled to control input of register-catch. EFFECT: expanded functional capabilities. 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 residual voltage at the storage capacitor in capacitive ignition systems of gas turbine engines.

 The well-known high voltage meter IVN-1 (described in the following source: High voltage meter IVN-1 8g2.746.015 RE UAKB "Lightning" Operation Manual), which is used to monitor the effectiveness of capacitive ignition systems. The meter is a pointer, and because of its inertia, it is not possible to register the parameters of fast-flowing pulse discharge processes in semiconductor spark plugs. In addition, the meter in its functionality is not applicable for measuring the residual voltage on the storage capacitor of capacitive ignition systems at the time of discharge extinction in candles.

 The IAN-1 amplitude voltage meter is also known (described in the following source: IAN-1 amplitude voltage meter 8g2.746.021 TO. UAKB "Lightning" Technical description). The meter is a pointer device and has the same disadvantages as the previous one.

 A known meter of the amplitude of the voltage developed by capacitive ignition units, described in the article [F.A. Gizatullin, V.N. Zaitsev, I.A. The great man. Digital meter for the amplitude of high-voltage voltage pulses in a capacitive ignition system / RZh Electrical Engineering N 1, 1991. Dep. in VINITI N 4755-B90, 1990], comprising a peak detector, an analog-to-digital converter (ADC), a comparator, a zeroing unit, a first one-shot, a second one-shot, a memory block, a memory control unit, a digital display unit, a voltage divider, and the divider output voltage is connected to the inputs of the comparator and the peak detector, the output of the latter is connected to series-connected ADCs, a memory unit, a digital display unit, the output of the comparator is connected to the inputs of the first and second one-shots, the output of the last is connected to start the input of the ADC and the input of the memory control unit, the output of the latter is connected to the control input of the memory unit, the output of the first one-shot is connected to the input of the zeroing unit, the output of the latter is connected to the control input of the peak detector.

 The disadvantage of this device is that in its functionality it is not applicable for measuring the residual voltage on the storage capacitor of capacitive ignition systems.

 The closest in technical essence and the achieved result is a device for measuring the breakdown voltage of discharge devices (AS USSR 1804211, class G 01 R 31/30, publ. 06/26/91.), Containing a power supply unit, a high voltage unit, a voltage divider , a sampling-storage device, analog-to-digital converter, indicator, level discriminator, two one-vibrators.

 The disadvantage of this device is that in its functionality it is not applicable for measuring the residual voltage on the storage capacitor of capacitive ignition systems.

 The objective of the invention is to improve the quality and completeness of evaluating the effectiveness of spark discharges in spark plugs by introducing additional nodes that allow measuring the residual voltage across the storage capacitor in capacitive ignition systems.

 The problem is solved in that in the residual voltage meter on the storage capacitor in capacitive ignition systems, comprising, a voltage divider, a first one-shot, a second one-shot, a sampling-storage device, an analog-to-digital converter, an indicator, in addition to the prototype, an additional current sensor is introduced, signal amplitude limiter, two-threshold comparator, matching delay circuit, register-latch, decoder, timer, while the current sensor is connected to the input of the signal amplitude limiter, in the course of the latter is connected to the input of the two-threshold comparator, the output of the latter is connected to the input of the matching delay circuit, the output of the latter, in turn, is connected to the inputs of the one-shot, controlling the input of the sampling-storage device, the output of the first one-shot is connected to the triggering input of the analog-to-digital converter, the output of the second a single vibrator is connected to the control input of the sample-storage device, the voltage divider is connected to the information input of the sample-storage device, the output of the latter is connected to The sequence connected analog-digital converter, the register latch, decoder, and an indicator, a timer connected to the control input of Registration latch.

In FIG. 1 shows a structural diagram of the inventive device
In FIG. 2 shows a timing diagram of the operation of the claimed device
The device includes: a current sensor 1, a voltage divider 2, a signal amplitude limiter 3, a two-threshold comparator 4, a matching delay circuit 5, a first one-shot 6, a second one-shot 7, a sampling-storage device (CVC) 8, an analog-to-digital converter (ADC) 9 , timer 10, register-latch 11, decoder 12 and indicator 13. Current sensor 1 is connected to the input of the signal amplitude limiter 3, the output of the latter is connected to the input of the two-threshold comparator 4, the output of the latter is connected to the input of the matching delay circuit 5, the output of the latter a series, connected to the inputs of one-shots 6 and 7, the control input of the sampling-storage device 8, the output of the first one-shot 6 is connected to the triggering input of the analog-to-digital converter 9, the output of the second one-shot 7 is connected to the control input of the sample-storage 8, voltage divider 2 is connected to the information input of the sampling-storage device 8, the output of the latter is connected to the analog-to-digital converter 9 connected in series, the latch register 11, the decoder 12 and the indicator 13, the timer 10 is connected to the control -governing entry of Registration latch 11.

The device operates as follows. An analog signal in the form of a damped sinusoid (Fig. 2A) of duration t _and from the current sensor 1 included in the discharge circuit of the ignition system is limited in amplitude and fed to the input of a two-threshold comparator 4, the output of which is a series of square pulses (Fig. 2B). The signal from the output of voltage divider 2 is shown in FIG. 2d. The residual voltage U _ost corresponds to the moment of discharge extinction (the moment of passage of the discharge current through zero in Fig. 2A). After this, another capacitor charge occurs and the voltage on it increases. The discrimination levels of the two-threshold comparator 4 are selected corresponding to the transition current of the preparatory stage of the discharge into a spark in a semiconductor candle, which is 2-3 orders of magnitude less than the amplitude of the current of the spark stage of the discharge. The preparatory stage of the discharge ends at time t ₁ (Fig. 2A). Next, the signal enters the coordination delay circuit (DLC) 5, where the gaps between the pulses are filled (Fig. 2B), and a signal is generated that is equal in time to the duration of the spark t _and (Fig. 2G). For this, a set of devices is used in accordance with the meter circuit the duration of spark discharges described in A.S. 1679416. By cutting the signal from the output of the CZS, the moment of the end of the spark stage of the discharge in the candle is recorded, and at this moment the IWS 8 is transferred to storage mode (time t _and in Fig. 2E). The voltage output diagram of the UVC is shown in FIG. 2E. Plot t ₂ -t ₃ corresponds to the storage mode in the UVX. Thus, the measured value of the residual voltage at the storage capacitor is recorded in the UVX. By slice of the signal from the DSC (Fig. 2G), the first 6 and second 7 one-shots also work. The signal from the output of the first one-shot 6 starts the ADC 9 (Fig. 23). After a period of time, obviously greater than the conversion time of the ADC, after cutting the signal from the second one-shot 7, the UVX is again transferred to the sampling mode (Fig. 2E, G).

 Since the repetition rate of discharge pulses in a candle can vary widely, a digital indication of the measured value of the residual voltage at the storage capacitor after each discharge at a high frequency makes it impossible to visually perceive the meter readings. Therefore, the reading of the measurement result from the ADC to the indication is made at strictly defined time intervals, adjustable by the user. For this, a timer 10 is used, which allows information to be recorded in the latch registers 11 only at specified intervals. The digital code with the measurement result from the register-latches is decrypted into a seven-segment code by the decoder 12 and fed to the indicator 13.

 So, the claimed invention allows to measure the residual voltage at the storage capacitor in capacitive ignition systems, and thus, improve the quality and completeness of the evaluation of the effectiveness of spark discharges.

Claims (1)

 The residual voltage meter on the storage capacitor in capacitive ignition systems, comprising a voltage divider, a first one-shot, a second one-shot, a sampling-storage device, an analog-to-digital converter, an indicator, characterized in that the device contains a current sensor, a signal amplitude limiter, a two-threshold comparator, a circuit coordination delays, timer, latch-register, decoder, while the current sensor is connected to the input of the signal amplitude limiter, the output of the latter is connected to the input of two-thresholds new comparator, the output of the latter is connected to the input of the matching delay circuit, the output of the latter, in turn, is connected to the inputs of the single-vibrator, controlling the input of the sampling-storage device, the output of the first single-vibrator is connected to the triggering input of the analog-to-digital converter, the output of the second single-vibrator is connected to the control input sampling-storage devices, the voltage divider is connected to the information input of the sampling-storage device, the output of the latter is connected to analog-digital connected in series th transmitter, the register latch, decoder, and an indicator, a timer connected to the control input latch.

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