SU1758279A1 - Apparatus for measuring time period of limiting current by transistorized switching devices of ignition system - Google Patents

Abstract

The device contains elements of galvanic isolation 1, 2, analog key 3, differentiating element 4, comparator 5, elements and 4.6, shaper 7 short pulses, RS-flip-flops 8, 9, D-flip-flop 10, generator 11 clock frequency measuring device 12. 1 z.p. f-ly, 2 ill.

Description

The invention relates to a measurement technique and can be applied to an automated measurement of the time value of breaking the current by transistor switches of the ignition systems of internal combustion engines.

The purpose of the invention is to increase the speed, accuracy of measurement and expand the field of application of the device.

FIG. 1 shows a functional diagram of a device for measuring the time of current limiting by transistor switches of ignition systems; in fig. 2 - functional scheme of the measuring device; in fig. 3 - timing diagrams of the basic elements of the device.

The device (Fig. 1) contains the first 1 and second 2 elements of galvanic isolation, analog key 3, differentiating element 4, comparator-Shaper 5, element 6, shaper 7 short pulses, first 8 and second 9 RS-triggers. D-flip-flop 10. bus Reset, which is connected to the first R-input of RS-flip-flops 8.9 and R-input of D-flip-flop 10, and the second R-input of RS-trigger 8 is connected to the output of the comparator-former 5 and the first input of the And 6 element the second input of which is connected to the direct output of the trigger 10 and the first input of the analog switch 3, and the output of the element 6 with the S input of the RS flip-flop 9, the second R input of which is connected to the C input of the trigger 10 and through the short-pulse shaper 7 the output of the second 2 elements of galvanic isolation. The D input of the trigger 10 is connected to the direct output of the trigger 8, the S input of which is connected to the Start bus. The inputs of the galvanic isolation element 1 are connected to the first and second contacts of the reference resistance R, and the output is connected to the second input of the analog switch 3. whose output through the differentiating element 4 is connected to the first input of the comparator 5. whose second input is connected to the reference voltage bus Don. The device also contains a clock frequency generator 11, a measuring device 12, the first, second, third, fourth, and fifth inputs of which are connected respectively to the direct output of the trigger 10, with inverse

trigger output 10. with direct trigger output 9, with clock generator output, with reset bus.

The measuring device contains And 13, 14, 15 elements, the first inputs of which are connected to the fourth input of the measuring device 12, and the outputs, respectively, with the summing input of the counter 16, the reversing counter 17 and the counter 18, the second inputs of the And elements 13, 14 connected to the first and third inputs of the measuring device va 12, code-frequency converter 19, frequency divider 20. decoder 21, RS flip-flop 22, reading device 23, the code inputs of the code-frequency converter being connected to the outputs of the counter 16, and the first second The inputs are connected respectively to the fourth and second inputs of the measuring device 12, the output of the code-frequency converter 19 is connected through a divider 20 to the subtractive input of the reversible counter 17 and the S input of the trigger 22. The R-input of which is connected via the decoder 21 to the discharge outputs of the re- A counter 17, the direct output of the trigger 22 is connected to the second input of the element 15, and the outputs of the counter 18 are connected to the reading device 23, while the installation inputs of the counters 16,17,18 are connected to the fifth input of the measuring device 12.

The device also contains a power bus 24 connected to the first contact of the ignition coil 25, the second contact K 3 is connected to the first contact of the reference resistance 26 (R): bus 27 Input 1, which is connected to the output of the controlled transistor switch 28 (TC), bus 28 Input 2, to which the pulses of the 1D.3 ignition sensor are received, bus 30 Start.

A transistor switch is not included in the device because it is a replaceable monitored element. FIG. 1 it is shown by dotted lines. Input 1 is load controlled TK. since the power circuit is connected to it, i.e. R, short circuit and power E.

The device works as follows. When the power is turned on, the memory elements are in an arbitrary state, therefore, initially by a signal on the Reset bus, they are set to the zero state.

When the trigger signal arrives at the bus, the trigger 8 is set to one state and thus prepares the D-trigger 10 for operation. And at time t2. when the C-input trigger 10 enters the front

control pulses that go to the bus. Input 2, trigger 10 switches and logical 1 from its direct output opens the analog switch to pass the current signal. At the same time, the potential of logical G will open element AND 13 of measuring device 12, and the pulses of the clock frequency generator will begin to fill the counter 16. A signal proportional to the current is emitted on the reference resistance, and when condition D i 0 is fulfilled, the differentiating element will generate a pulse, the amplitude of which will exceed the value of uon. At this moment, the parator will generate a pulse, which sets the RS-flip-flop 8 to the zero state, and through the element 6, the potential of the logical 1 opened from the direct output of the D-flip-flop 10. RS-flip-flop 9 will be set to one and that element 14 of the measuring device opens up for passing pulses of the clock frequency generator to the summing input of the reversible counter 17. At the moment the control pulses slice arrives, the short pulse shaper 7 sets the RS flip-flop 9 to O and thereby closes the And 14 dl element impulse clock. In the counter 17 will be generated code N r f. And at the moment when the C-input of the D-flip-flop arrives at the front of the next control pulse and the D-flip-flop switches to the D-inputs state, i.e. logical O, which closes the analog key, the element And b and the element And 13 of the measuring device 12. Thus, in the counter 16 the code of the period of the control pulses, i.e. Ni r1 - f $. Further, the process of measuring the ratio of codes continues only in the measuring device in the presence of a clock frequency and a conversion resolution signal received from the inverse output of the D flip-flop 10. At the end of the period T r1, the conversion resolution signal enables the code-frequency converter 19 to work. The output frequency of the divider is determined by the expression

f20 fi9 K, where fig fp Ni,

The K-constant determined by the division factor of frequency divider 20. The output pulses of the divider 20 are fed to the subtracting input of the reversible counter 17 and the S is the input of the RS flip-flop 22. which is set to one at the first pulse of the divider. After a certain time when the condition will be met

N2 0, the pulse of the decoder 21 will set the trigger 22 to the zero state. The time interval during which the trigger 22 holds the AND 5 element open is determined by the expression

  G2 K / P.

At the same time, the pulse of the decoder 21 will set the counter 16 to zero, and the readout device will receive a command to indicate the code Mz recorded in counter 18. Since element 15 is open for a time Gz, the counter code at the clock frequency f will be determined by the expression

Mz gz fo

considering the resulting expressions for Gz, the last expression will be

№-§к.

Since the period of the control pulses is equal to the time interval m, and the division ratio is K 100, the last expression defines the percentage of the time limit for the current TK to the period of the control pulses.

If it is necessary to obtain the values of the control pulse period and the pure current limiting time, the code values of the counters 16 and 17, respectively, can be used. The counter counting signal is a logical unit at the inverse output of the D-flip-flop 10.

It should be noted that the measurement of time intervals whether T2 is provided on a single clock, i.e. for one period, therefore, the error due to the instability of the control pulse period is eliminated.

Claims (2)

1. A device for measuring the current limiting time by transistor switches of ignition systems containing a power supply bus connected to the first contact of the ignition coil, the second contact of which is connected to the first contact of the reference resistance, the second contact of which is connected to the bus Input 1, bus Input 2 of the ignition sensor connection, Start bus, measuring device, characterized in that, in order to improve speed, measurement accuracy and expansion of the field of application, the first and second second galvanic isolation elements, analog key, differentiating element, comparator driver, element I, driver of short pulses, clock frequency generator, first and second RS-flip-flops, D-flip-flop, reset bus, which is connected to the first 0 R-input of the first and second RS-flip-flops and R-input of the D-flip-flop, and the second R-input of the first RS-flip-flop is connected to the output of the comparator-former and the first input of the And element, the second input of which is connected 5 with a direct output of the D-flip-flop and the first input of an analog switch, and the output is connected to the S-stroke of the second RS-flip-flop. the second R input of which is connected to the C input of the D0 flip-flop and the output of the second galvanic isolation element through the shaper of short pulses, the input of which is connected to the bus Input 2. and the D-input of the D flip-flop is connected to the direct output of the first RS-flip-flop, S -input which is connected to 5 bus Start, the first and second inputs of the first galvanic isolation element are connected respectively to the first and second contacts of the reference resistance, and the output is connected to the second input of an analog switch, the output of which is connected to the first input of the comparator-former via the differentiating element, the second input of which is connected with the reference voltage bus, the measuring device, the first, second, third, fourth and fifth inputs of which are connected respectively with the direct output of the D-flip-flop, the inverse output of the D-flip-flop, with a direct output the second course of the RS-flip-flop, the output of the generator frequency, bus Reset. 2. Device pop. 1, characterized in that the measuring device contains the first, second and third element I, the first inputs of which are connected to the fourth input of the measuring device, and the outputs connected to the summing inputs of the first counter, reversible counter and second counter, respectively, and the second inputs of the first and second items 0 And connected respectively to the first and third inputs of the measuring device, code-frequency converter, frequency divider, descrambler, RS flip-flop, reading device, while the bit inputs 5 of the code-frequency converter is connected to the outputs of the first counter, and the first and second inputs, respectively, with the fourth and second inputs of the measuring device, the code-frequency converter output is connected via a frequency divider with the subtracting input of the reversible counter and the S input of the RS flip-flop, the R-input of which is connected through the decoder to the discharge inputs of the reversible counter, the direct output of the RS flip-flop connected to the second input of the third element And, and the outputs of the second counter connected to the counting device. The installation inputs of the second and reversible counters, as well as the first installation input of the first counter g are connected to the fifth input of the measuring device, and the second installation input of the first counter is connected to the enabling input of the reading device and the decoder output.