SU1612221A1 - Device for determining top dead center of i.c. engine - Google Patents

Abstract

The purpose of the invention is to increase the speed and accuracy of the formation of the top dead center (TDC) when changing the engine speed. The device comprises an induction sensor, a normalization unit, a high level comparing unit, a first zero level comparing unit, first and second digital switches and a first pulse shaper, and a sample signal generator, first and second keys, a differential integrator, a second zero level comparing unit and a second pulse shaper. The device automatically generates the TDC mark signal at the moment of polarity change of the induction converter signal regardless of the type of TDC marks: metal pin (protrusion) or hole (notch) and allows determining the type by comparing the duration and pause of the high level comparing signal and the induction sensor signal performance of the TDC mark in one revolution of the engine crankshaft, and consequently, reduce the time to establish a formal operation and, accordingly, increase the speed tvie device. 17 il.

Description

The invention relates to instrumentation, in particular to devices for testing internal combustion engines, and can be used in engine diagnostics and control systems.

The aim of the invention is to improve the speed and accuracy of the formation of the top dead center mark when the engine speed changes.

FIG. 1 shows a functional diagram of the device; in fig. 2 - signal at the output of the normalization unit when performing the top dead center mark (TDC) in the form of a metal pin; in fig. 3 - signal at the output of the high level comparator when performing

TDC marks in the form of a pin; in fig. 4 shows the signal at the output of the zero level comparator when the B.MT mark is in the form of a pin; in fig. 5 - signal to. the output of the second pulse shaper when performing the mark of TDC in the form of a pin; in fig. 6 - the signal at the output of the differential integrator when performing a TDC mark in the form of a pin; in fig. 7 - the signal at the output of the first switch when performing TDC mark in the form of a pin; in fig. 8 - the signal at the output of the second switch when performing TDC mark in the form of a pin; in fig. 9 - signal at the device output when performing the TDC mark in the form of a pin; in fig. 10 - unit output signal

Oi

ND HchE bO

normalization when performing the TDC mark in the form of a hole; in fig. 11 is a signal at the output of the output level comparing unit when the TDC mark is executed in the form of openings; in fig. 12 is a signal at the output of the zero level comparator when performing an TDC mark in the form of an aperture; in fig. 13 is a signal at the output of the second pulse former when the TDC mark is in the form of an aperture; in fig. 4 - signal at the output of the differential integrator when performing TDC mark in the form of a hole; in fig. 15- signal at the output of the first switch when performing TDC mark in the form of a hole; in fig. 16 - the signal at the output of the second switch when performing TDC mark in the form of a hole; in fig. 17 - the signal at the device output when performing the TDC mark in the form of a hole.

The device (Fig. 1) contains an induction sensor 1, a normalization unit 2, a high level comparing unit 3 and a first zero level comparing unit 4, the first 5 and second 6 switches, the first pulse generator 7. The output of sensor 1 is connected via block 2 to the inputs of blocks 3 and 4, the outputs of which are connected to the direct and inverse inputs of digital switches 5 and 6, respectively, and the outputs of the latter are connected respectively to the direct control input and signaling input of the driver 7.

The device additionally introduces the generator 8 of the reference signal, the first 9 and second 10 keys, the differential integrator AND, the second zero level comparing unit 12, the counting trigger 13 and the second pulse generator 14. The output of the generator 8 is connected to the signal inputs of the keys 9 and 10. The output of the block 3 is connected directly to the direct control input of the key 9, to the first inverse control input of the key 10 and the counting input of the trigger 13, and through the driver 14 to the setup input of the differential integrator 11 .

The direct and inverse inputs of the differential integrator 11 are connected to the outputs of the keys 9 and 10, respectively, and its output is connected via block 12 to the second inverse control input of the key 10, the inverse control input of the driver 7 and the control input of the counting trigger 13. The output of the latter is connected to the inputs control digital switches 5 and 6. The output of the imager 7 is combined with the output of the device.

The device works as follows.

When the engine is not running, the signal pulses at the outputs of the sensor 1, block 2, and consequently, at the inputs of block 3 and 4 are absent. Accordingly, the signal at the output of the high level comparing unit 3

n has a logic level "Oh, a blocking key 9 and an unlocking key 10, a generator signal 8 (pulses of an exemplary frequency f or an exemplary voltage f / c)

enters through the unlocked key 10 to the inverse of the differential integrator 11. The signal at the output of the latter (code or voltage level) decreases and becomes equal to zero. At this moment, block 12 is triggered and at its output a logical signal "1 blocking key 10 and driver 7 is generated. As a result, regardless of random changes in the signal at the output of block 4, the comparing zero level caused, for example, by noise, the signal at the output of the device not formed.

After starting the engine, bipolar pulses with a frequency equal to the frequency of rotation of the engine shaft appear at the output of sensor 1 and, respectively, at the output of block 2 and at the inputs of blocks 3 and 4.

At. When the positive signal half-wave of sensor 1 (Fig. 2) appears, block 3 is triggered when the signal reaches the U + level and a logical signal "1 (Fig. 3) is generated at its output. When a negative signal half-wave of sensor 1 appears, at the moment when the signal LL reaches the signal, block 3 is triggered and a logical signal "O" is generated at its output.

0 Thus, when the engine is running, pulses are generated at the output of unit 3 with a follow-up period T equal to the follow-up period of impulses of sensor 1 and duration t. The leading edge of the impulse at the output of unit 3 corresponds to

5 when the front of the positive half-wave reaches the signal of the threshold 1 sensor, and its rear front reaches the moment when the front reaches the negative half-wave. The sensor 1 signals the threshold LL. Pulses are generated at the output of block 4 (FIG. 4)

 also with the period of following T, equal to the period of following the signal of sensor 1, and a duration equal to the duration of the pulse of a positive field of signal of sensor 1 at the level of zero potential.

five

The signal from the output of block 4 comes

to the direct and inverse inputs of switch 6, the state of which is determined by the level of the output signal of the counting trig. Hera 13.

0 The signal from the output of block 3 is fed to the counting input of the trigger 13, to the input of the imaging unit 14, to the control input of the key 9, to the first inverse control input of the key 10 and to the direct and inverse inputs of the switch 5, the state of which

5 is determined by the level of the output signal of the counting trigger 13. PU the leading edge of the pulse from the output of block 3 at the output of trigger 13 forms a 5 h level of the logical signal corresponding to the level of the logical signal at the output of block 12 while forming 14 produces a short pulse (Fig. 5), resetting the differential integrator 11 in the state corresponding to the zero signal at its output. Block 12 is triggered, and at its output a logical "1 blocking key 10 signal is generated from the second inverted control input and the driver 7 to the inverted control input. During the duration t of the pulse at the output of the block 3, the key 9 is unlocked, and the key 10 is blocked. In the pause, the signal of block 3, key 9 is blocked, and key 10 is unlocked at the first inverse control input.

From the moment the pulse at the output of the driver 14 ends, the signal from the output of the generator 8, which comes through the switch 9 to the direct input of the differential integrator 11, causes the signal to rise at the output of the latter (Fig. 6). At the same time, at the output of block 12, a logical signal "O" is generated that unlocks the key 10 via the second inverted control input and the driver 7 via the inverted control input. By the time the pulse ends, a signal proportional to the pulse duration r is formed at the output of the block 3 over the course of the differential integrator 11. After the end of the pulse at the output of block 3, the key 10 is unlocked by both control inputs and the signal from the output of generator 8 begins to arrive at the inverse of the differential integrator II, causing a decrease in the signal at its output by an amount proportional to the duration d of the pause between pulses at the output of block 3. When the signal at the output of the differential integrator 11 has time to be reduced to zero. At this moment, the block 12 is triggered, and at its output a logical signal "1 blocking key 10 is formed, and the change in signal at the output of the integrator 11 is stopped. As a result, at the time of the rising edge of the next pulse of the block 3, a logical signal "1" is generated at the output of the counting trigger 13, corresponding to the signal level at the output of block 12. The process of comparing the pause durations "and the pulse t of the signal at the output of block 3 repeats the same result in the following periods of the T of this signal, therefore, the state of the counting flip-flop 13 does not change and a logical signal "1."

When the signal at the output of the differential integrator 11 does not have time to decrease to zero, the state of block 12 also does not change. As a result, at the moment when the front of the next pulse of block 3 appears, at the output of the counting trigger 13 a logical signal "O is generated, corresponding to the signal level at the output of block 12. The process of comparing the pause durations" and the pulse t, the signal at the output of block 3 repeats the same result in the next periods of the following G of this signal, therefore, the state of the counting trigger 13 does not change and the logical "O" signal is constantly formed.

Let the sensor 1 is installed against the TDC mark, made in the form of a pin (protrusion) on the engine flywheel. In this case, the moment of zero crossing of the signal at the output of sensor 1 and, therefore, at the inputs of blocks 3 and 4 corresponds to the time of the front of the negative half-wave of sensor 1. As a result, first during the bipolar pulse of sensor 1, first (put a half-wave at the front) block 3 is triggered, and then (on the front of the negative half-wave) its reverse triggering (Fig. 3). Thus, at the output of block 3, a sequence of relatively short pulses with a duty cycle close to the ratio of the circumference of the flywheel to the length of the TDC mark is formed. In this case, the inequality holds true and, therefore, no more than one revolution of the motor shaft at the output of the counting trigger 13 sets a logical signal "1. The latter unlocks the direct output of switch 5 and the inverse input of switch 6. As a result, from the output of block 3 in the polarity interval of the bipolar sensor pulse, the direct control input of the driver 7 sends a non-inverted pulse through switch 5, unlocking the driver

7 to the direct control input, and to the chriia. ibHhn i vholol. the last arrives the pulse inverted by the switch 6, which is formed at the output of the block 4.

When the polarity of the signal from sensor 1 is changed at the input of block 12, a logical signal "O" is generated, and therefore the driver 7 is unlocked at both control inputs. The leading edge of the pulse at the output of switch 6 (Fig. 8) corresponds to the zero crossing point of the signal from sensor 1 and triggers the shaper 7. The device generates a short pulse at the device output (Fig. 9), the front of which corresponds to the specified polarity c; signal at the output of sensor 1 and, therefore, in the middle of the TDC mark.

Let the sensor 1 is installed against the mark TDC, made in the form of a hole (groove) in the engine flywheel. In this case

the moment of zero crossing of the signal at the output of sensor 1 (Fig. 10) and at the inputs of blocks 3 and 4 corresponds to the moment of occurrence of the positive half-wave of the signal of sensor 1. As a result, during the duration of the bipolar pulse of sensor 1, the first (on the front of the negative half-wave) occurs the reverse triggering of block 3, and then (at the front of the positive half-wave) its direct triggering (Fig. 11).

Thus, at the output of block 3, a sequence of relatively short pauses and long-term pulses m is formed with a duty cycle close to the ratio of the circumference of the flywheel and the difference of the lengths of the circumference of the flywheel and the TDC mark, i.e. close to unity. In this case, the inequality holds true and, therefore, no more than one revolution of the motor shaft at the output of the counting trigger 13 sets the logical "O signal". The latter unlocks the inverse input of switch 5 and the direct input of switch 6. As a result, from the output of block 3 in the polarity interval of the bipolar pulse of sensor 1, the first input of the control of form 7 on the switch 5 receives an inverted pause that unlocks the driver 7 through this input control, and the signal input of the imager 7 receives a non-inverted pulse generated at the output of block 4. At the moment of polarity change of the signal of sensor 1, the signal of the logic 12 and shaper 7 is unlocked at both control inputs. The pulse front at the output of switch 6 (Fig. 16) corresponds to the zero crossing point of the sensor 1 signal and triggers the shaper 7. The device generates a short pulse at the device output (Fig. 17), the front of which corresponds to the specified moment of polarity change of the sensor 1 signal, and the middle of the TDC tag.

Claims (1)

Invention Formula A device for determining the top dead center of an internal combustion engine, containing an induction sensor, a normalization unit, a high level comparing unit, a first zero level comparing unit, and a second switch equipped with direct and inverse inputs, and a first pulse driver made with a direct control input and a signal input, the output of the inductive sensor connected through the normalization unit with the input of the comparing unit the high level and the input of the first zero leveling block, the outputs of which are connected to the direct and inverse inputs of the first and second switches, respectively, the outputs of the latter are connected respectively to the direct control input and the signal input of the first driver, in order to improve speed and precision, it additionally introduced a model signal generator, the first key with signal and direct control inputs, the second key with signal and two inverse control inputs, di an integrator made with direct, inverse, and setup inputs, the second a zero-level comparing unit, a counting trigger equipped with a counting input, and a control input and a second pulse shaper, the first pulse shaper is equipped with an inverse control input, the first and second switches are made with 0 control inputs, the generator output of the reference signal is connected to the signal inputs of the first and second keys, the output of the high level comparing unit is connected directly to the forward control input of the first key, to the first inverse control input of the second key and to the counting input of the counting trigger, and the second pulse shaper is connected to the setup input of the differential integrator, the direct and inverse inputs of which are connected respectively to the outputs of the first and second keys, and the output to the differential cially integrator coupled via a second unit calibration of zero crossings from the second inverted control input of a second key with an inverted input uprav5leni first pulse shaper and to the input of a control latch countable, and yield of the latter is connected to the control inputs of the first and second switches. Phie.E /: Fiz. / 7