SU1054710A1 - System for measuring combustion knock in internal combustion engine - Google Patents

Abstract

DETONAKHSSH MEASUREMENT SYSTEM IN THE INTERNAL COMBUSTION ENGINE, containing a knock sensor, a control unit, a measuring unit, and cue element 2I, two-input trigger and clock generator), the latter through a nepBhdt input trigger | , so that, in order to increase accuracy by synchronizing the measurement with “4 maximum combustion pressure”, the speed change sensor and the comparator were entered into it, including tion to the other input 2I. Q1 4 J

Description

The invention relates to engines of internal combustion, more specifically to systems for measuring detonation by engine design vibrations or by acoustic radiation in its operation, and can be used in the study of the detonation resistance of gasolines in studying the anti-knock properties of engines in reverse ignition control systems communication by the criterion of detonation.

Known measurement systems for toning are known, comprising a knock sensor, a control unit, a measuring unit and a pulse shaper. The control unit is located between the knock sensor and the measurement unit. According to the signals from the pulse former, the start-up unit, the control unit, passes the signal of the knock sensor to the input of the measuring unit for a certain sector of the motor shaft rotation, which ensures the release of the useful signal from the noise over time. This sector is located near the upper Dead Point (mWt). Compress the engine, near which during operation it is located the maximum pressure point of the cycle. (P), mainly determining the moment of occurrence of the detonation G1 3.

When conducting research with the engine, the adjustments of the power supply and ignition systems of the engine have to be significantly changed, which causes significant displacements of the P point (and the moment of detonation) relative to the BMC of compression, V. a drawback device.

Known systems for measuring detonation in an internal combustion engine, the contents of a knock sensor, a control unit, a measuring unit, a logic element 2I, a two-input trigger and a sync pulse generator are known, the latter being connected to the control units through the first trigger stroke measurement, and the control unit is parallelly connected to the detonation sensor and to the second input of the trigger C2,

In such systems, at the moment the spark plugs are discharged, the sync pulse generator switches the trigger, and a potential appears at its output.

which allows the passage through the element 2H of the pulse at the time of the VMT compression from the driver of the starting pulses. This pulse triggers the control unit, which generates a pulse, the duration of which determines the sector of rotation of the engine shaft. /.

during which the signal from the vibration sensor passes to the input of the measuring unit.

The disadvantage of this system is that the position of the sector of the shaft rotation, at which detonation is measured, does not depend on the actual location of the point P (and the moment of detonation) in the angle of rotation of the shaft. Therefore, with its considerable displacements, which occurs during engine research, the accuracy of the detonation measurement decreases, in a number of cases the measurement becomes impossible.

The purpose of the invention is to increase accuracy.

This goal is achieved in that the detonation measurement system in an internal combustion engine contains a detonation sensor, a control unit, a measurement unit, a logic element 2I, a two-input trigger and a clock sync pulse, the latter via the first trigger input connected to the input with one input of the logic element 2I, is connected in series with the control and measurement units, and the control unit is connected in parallel with the knock sensor and the second trigger input, the speed sensor for changing detection and comparator .vklyuchennye sequentially at the other input of the logical element 2I.

FIG. 1 shows a block diagram of a knock measurement system; in fig. 2 temporary diagram of her work.

The system contains a knock sensor 1, a control unit 2, a measurement unit 3, a logic element 2 and 4, a driver of sync pulses 5, a two-input trigger 6, a sensor for the rate of change of pressure 7, comparators 8. In the figure; 2 denotes: signal 9 — pressure change in the combustion chamber, signal 10 from the knock sensor 1, signal 11 from the clock generator 5, output signal 12 from the two-input trigger 6, signal 13 from the speed sensor

changes in pressure 17, signal 14 of the comparator 8, 5 - a pulse corresponding to the time of passage of the signal from knock sensor 1 through the control unit 2, signal 16 - detonation at the input of measuring unit 3, signal 17 - detonation.

The system works as follows

At the moment of discharge on the candle, the ignition signal 11 from the clock generator 5 switches the two-input trigger 6, and a signal 12 appears at its output. At the time point corresponding to point Pj, the output signal of the rate of change of pressure sensor 7 becomes zero. This moment of time is recorded by the comparator 8 as a pulse 15, which passes through the open element 2I and starts the control unit 2, the control unit passes the signal 10c of knock sensor 1 to the measurement unit 3 during the time interval.

i corresponding to the duration of the signal 16, carried out 4) the separation of the signal 17 about the detonation, from the background noise. When the signal 16 is cut (at its end), trigger 6 switches to the initial state and blocks element 2I, therefore signals 14 from comparator 8, corresponding to other (besides point P) extremes of pressure in the combustion chamber, do not pass to the control unit, which prevents its false starts and thereby eliminates the influence of interference

and knock measurement results

 -. , In the proposed detonation measurement system in comparison with the object, the position of the sector of rotation, the shaft of the engine on which the measurement is made, is synchronized with the actual location of point P. Moreover, the accuracy of detonation measurement increases by 25-30JJ, which gives the corresponding economic effect.

/ J 16 17

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Claims (1)

DETONATION MEASUREMENT SYSTEM IN THE INTERNAL COMBUSTION ENGINE, * comprising a knock sensor, a control unit, a measurement unit, 2I logic element, a two-input trigger and a sync pulse generator, the latter through the first input of the trigger connected to the output with one input of a logical element 2 and * control and measurement, and the control unit is connected in parallel with the knock sensor and with the second trigger input, characterized in that, in order to improve accuracy by synchronizing the measurement with the the maximum combustion pressure, it introduced a pressure change rate sensor and a comparator, connected in series on the other input of the logic element 2I 1 1054710