SU1442939A1 - Spark duration meter - Google Patents

Abstract

The invention relates to electrical measuring equipment, in particular, devices for measuring the duration of fast pulses, and can be used to measure the duration of processes in spark plugs, electrical discharges and devices of similar purpose. The aim of the invention is to increase the accuracy of measurements and expand the functional capabilities of the device by measuring the attenuation time of the processes, the invention is achieved by implementing a receiving device in the form of a current sensor 1, rectifying the received signal with a rectifier 2 and then generating an aggregate of discrete signals from an analog signal using a discriminator 4 fauns, one-oscillators 5.7, elements OR 6.8, inverters 9.10 and measurement of the duration of the formed pulse by the block 11 of the account. The device, in addition, contains the amplifier 3, 2 Il. i

Description

N5

WITH

with with

The invention relates to electrical measuring equipment, in particular, devices for measuring the duration of fast pulsed processes, and can be used to measure the duration of electric discharge processes in spark plugs, electrical discharges and devices of similar purpose.

The purpose of the invention is to improve the measurement accuracy and expand the functionality of the device.

FIG. 1 is a block diagram of a spark duration meter; Fig. 2 shows timing diagrams explaining its principle of operation.

The spark duration meter (Fig. 1) contains a current sensor 1, a rectifier 2, an amplifier 3, a discriminator 4 levels, the first single-oscillator 5, the first element OR 6, the second one-oscillator 7, the second element OR 8, the first inverter 9, the second the inverter 10 and the counting unit 11, the output of current sensor 1 being connected to the input of rectifier 2, the output of which is connected to the input of amplifier 3, the output of the latter connected to the input of the discriminator 4 level, the output of which is connected to the input of the first single vibrator 5, the output of which is connected with the input of the first element OR 6, the second input of the element OR 6 connect it. With the discriminator 4 input level 4, the output of the first element IL 6 is connected to the input of the second one-oscillator 7, the output of which is connected to the first input of the second element OR 8, the second input of which is connected to the output of the first inverter 9, whose input is connected to the output of the first element OR 6, the output the second element OR 8 is connected to the input of the second inverter 1.0, the output of which is connected. with the input of block 11 of the account.

The meter works as follows.

Current sensor 1, for example, a low-resistance non-inductive shunt, is connected in series with the spark gap under test (candle), in which spark-like discharges form with a certain frequency. The shape of the current curve through the candle is shown in figa. Before the start of the spark discharge, a slight current of the so-called preparatory stage of the discharge flows through the candle (section 0-t). Further develops

five

0

five

0

five

0

five

0

five

from the spark, a discharge stage (region t, –t), the duration of which is measured by the device. The signal from current sensor 1 is rectified by rectifier 2 and amplified to the required level by amplifier 3. (Amplification is necessary when using an active rectifier that lowers the signal level). The signal at the output of the amplifier 3 is shown in Fig.26. In the discriminator 4 of the level, the signal is compared with a predetermined reference value, at which the logical level 1 appears at the discriminator output (Fig. 2c). The reference value is selected on the basis of statistical data on the values of the transition current of the preparatory stage of the discharge to the spark in semiconductor spark plugs.

The first one-shot 5 triggers a slice of the incoming pulses and generates a pulse of constant duration (Figure 2d), which in the first element OR 6 adds to the signal from the discriminator 4 level (Figure 2d) and goes to the second one-shot 7 and the first inverter 9. ( The pulses at the output of the first one vibrator 5 fill the gaps between the pulses at the output of the discriminator level 4). The signal at the output of the first element OR 6 exceeds the duration of the spark by the value of the pulse from the output of the first one-shot 5. The signal at the output of the first inverter 9 is shown in Figure 2e. Triggering on the front of pulses coming from the first element, OR 6, the BTopofi one-shot 7 generates a single pulse of the same duration (Fig. 2g) as the pulses on you during the first one-shot 5. In the second element OR 8, the pulse from the output of the second one-shot 7 adds with a signal from the output of the first inverter 9. The signal at the output of the second element 8 is shown in fig.2z. At the output of the second inverter 10 (Fig. 2i), an Impulse is obtained, the duration of which is equal to the duration of the spark. Measurement of the generated pulse is carried out by a known method in the block 11 of the account.

Claims (1)

The formula invented and; .. A spark duration meter containing a receiver unit F U