SU1079875A1 - Device for measuring advance angle of diesel engine fuel injection - Google Patents

Abstract

DEVICE MEASUREMENT OF THE ANGLE OF LEADING VPRB1SKA TONLEV DIESEL, containing the sensors of the investigated processes, the first and second pulse shapers, the first, second and third circuits And, the top dead center sensor (TDC), the pulse generator, the first and second registers, the display unit and the trigger, and the sensor TDC through the first pulse shaper and the counting input of the trigger is connected in parallel with the first inputs of the first and second circuits And, the outputs of which are connected to the inputs of the first and second registers, respectively, the second input the first AND circuit is connected to the second input of the third AND circuit, to which the display unit is connected, and the sensors of the processes under study are connected to the second driver, which is different from the fact that, in order to improve the accuracy in transient modes of operation of the diesel engine, schema-ia or. additional AND circuits, the number of which is equal to the number of cylinders, and a frequency to voltage converter, the pulse generator being controlled, an OR circuit is connected to the sensors of the processes under study with a second driver connected to the second input of the second circuit, to which connected through a frequency converter to the voltage control input of the pulse generator, the output of which is connected to the second input of the first circuit. And the inverse output of the trigger is connected to the reset buses to the zero state of the first and second registers, divide Only the frequencies are connected to the first AND circuit with the first register, the first inputs of the third AND circuit and additional AND circuits are connected to the direct outputs of the second register, the second inputs of the additional AND circuits are connected to the second input of the third And circuit, the third inputs of the third circuit. Both the additional circuits and are connected to the corresponding inverse outputs of the first register, and the outputs of the additional circuits AND are connected to the inputs of the display unit. With “Lo ^ co00 ^ Sense 1

Description

The invention relates to diagnosing an engine of internal combustion; 1 and may be used to measure the advance angle of diesel injection engines. The device for measuring the angle of the onierger and diesel fuel injection is known, containing iiiUie sensors of the studied iroceee, first and second pulse shapers, first), second and third schemes I, upper dead center sensor (TDC), geyrator of pulses, first and second registers, block indication and trigger, with the TDC sensor being connected via the first imiuleer driver and counting trigger input in parallel to the I and the third inputs of the first and second circuits AND, whose inputs are connected to the inputs of the first and second registers, respectively, the second input of the first Hema and coupled to the second input of the third AND circuit to which is connected iidikatsii unit and sensors of the processes connected with the second generator I. The known device is characterized by reliability evaluation povpnennoy technical state of the internal combustion engine in its raboTbi of established conditions. In the prototype device, the injection advance angle is calculated as the ratio of two digital codes, one of which is formed by filling the interval of time from the beginning of the sensor signal of the process under investigation to the arrival of the piston at TDC, and the other is the digital equivalent of an angle of 720 ° by filling in a doubled period of shaft rotation with the same constant frequency emulsions. However, the obtained value of the advance angle corresponds to the real one only when the indicated codes are formed at the same angular velocity of the engine shaft. Otherwise, the calculated value of the angle of advance differs from the actual, because if the angular velocity of the shaft is changed, the above-mentioned time interval and digital equivalent of the angle of 720 ° change (since for a different rotation period, one rotation of the shaft corresponds to a different number of pulses ) and the relation of digital codes differs from the ratio of the angles corresponding to these codes. In this connection, the accuracy of measuring the fuel injection advance angle of a diesel engine operating in a transient velocity mode is low. The purpose of the invention is to increase the accuracy of measuring the fuel injection advance angle in transient high-speed diesel operation modes. This goal is achieved by the fact that, in the diesel fuel injection advance measurement device containing sensors of the processes under study, the first and second pulse formers, the first, second and third circuits AND, the TDC sensor, the pulse generator, the first and second registers, the display unit and the trigger, moreover, the TDC sensor is connected through the first pulse shaper and the counting input of the tri11er in parallel to the first inputs of the first and second I circuits, the outputs of which are connected to the inputs of the first and second registers, respectively, the second input of the first AND circuits are connected to the second input of the third AND circuit, to which the display unit is connected, and the sensors of the processes under study are connected to the second driver, a frequency divider, an OR circuit, additional AND circuits, the number of which is equal to the number of cylinders, and a frequency converter to the voltage, the pulse generator is controlled, the OR circuit is connected to the sensors of the processes under investigation with the second driver connected to the second input of the second AND circuit, which is connected through the frequency converter to the control voltage the pulse generator, the output of which is connected to the second input of the first circuit AND, the inverse trigger output is connected to the reset buses in the zero state of the first and second registers, the frequency divider is connected to the first circuit I, and the first register, the first inputs of the third circuit AND Additional circuits And are connected to the direct outputs of the second register, the second inputs of the additional circuits And are connected to the second input of the third circuit And, the third inputs of the third circuit And and additional circuits And are connected to the corresponding inverse outputs of the first register, and the outputs of additional circuits And connected to the inputs of the display unit. FIG. 1 shows a block diagram of the proposed device; in fig. 2 shows time diagrams of input and output signals of the elements of the device in case it is used to measure the fuel injection advance angle of a three-cylinder two-stroke diesel engine. The device contains a sensor 1 (TDC) of one of the cylinders, for example, the first, the output of which through the first driver 2 pulses is connected to the counting input of trigger 3. The forward output of trigger 3 is connected to the first inputs of the first and second circuits 4 and 5. Sensors 6-8 of the fuel injection process under study, for example, moving the injector needle, are connected to the inputs of the OR 9 circuit, the output of which through the second pulse shaper 10 is connected to the second input of the second circuit AND 5 and the frequency converter 11 to the voltage. The output of the frequency converter 11 to voltage is connected to the input of a controlled generator of 12 pulses, the output of which is connected to the second inputs of the second circuit AND 4, the third circuit AND 13, additional circuits And 14 and 15. The outputs of the circuit 13-15 are connected to the inputs of the display unit 16. The output of the first circuit AND 4 through the frequency divider 17 is connected to the input of the first register 18, and the output of the second circuit AND 5 is connected to the input of the second register 19. The reset buses of registers 18 and 19 to the zero state are connected to the inverse output of trigger 3. The first inputs of the third And 13, additional And 14 and additional An additional AND 15 circuit is connected to the first, second, and third direct outputs of the second register 19, respectively, and the third inputs of these circuits are connected to the first, second, and third inverse outputs of the first register 18, respectively. The device operates as follows. If in the initial state the trigger 3 is reset, then the first 18 and second 19 registers are reset, and the passage of pulses to their inputs is impossible due to the closed state of the first AND 4 and second AND 5 circuits. In this case, zero signals act on the first inputs of the AND 13-15 circuits, as a result of which there are no indications on the display unit 16. With the passage of the piston of the first cylinder through the TDC sensor 1 generates a signal, resulting in the output of the first driver 2 pulses a single impulse Uj appears (see Fig. 2), sets the trigger 3 to one and unlocks the And 4 and 5 circuits. following the output impulses of the second pulse shaper 10 pulses are first converted into a constant (in sign) voltage with the help of frequency converter 11 into a voltage, and then into a high frequency ft2 using a controlled oscillator 12, i.e. f | 2 floKllKii , (1) where Kji - coefficient before chi transducer 11, the transmission coefficient KIJ-controlled oscillator. Since fuel injection in a three-cylinder two-stroke diesel engine occurs three times per shaft revolution, the frequency f following is three times higher than the frequency of rotation of the shaft fjp, and the expression (1) can be written as follows, using f-f -1 / V (–3 K (1 Kji hi Jisp l. (2.) where wJpp is the angular velocity of the diesel shaft. Therefore, at the second inputs, the And 4, 13, 14 and 15 schemes always receive Uu pulses, the frequency of which is determined by the expression (2) Since the first matching circuit of AND 4 is open, the output pulses of the generator 12 are fed to the input of the frequency divider 17. The frequency divider 17 transmitting power (KnKii), so that pulses appear at its output with a frequency of 1 st, and for one rotation of the shaft of these pulses there will be as many cylinders as the diesel. Since the unlocking of the AND 4 circuit and the start of operation of the frequency divider 17 coincides with The moment of arrival of iiopniHH pervogg) qi / shndra to the top dead center, the moments of formation of impulses IJj correspond to the moments of entry iiopniHefi of the remaining cylinders at TDC. Thus, at the entrance of the second register 19, the impulses corresponding to the starting points of fuel injection into the diesel cylinders appear, and at the entrance of the first register 18 - impulses corresponding to registrats of pistons entering the upper dead points. If the order of operation of the cylinders 1-2-3, then, in order of FIG. 2 (when counting from left to right) impulse Llo corresponds to lifting the needle of the second cylinder, second pulse lJ (, - raising the needle of the third cylinder, third pulse Uioi - lifting the needle of the first cylinder. At the same time, the first В1,1 input pulse of the divider frequency Uir corresponds to entering TDC piston BTOpoio is a cylinder, the second impulse is Llr - entering the third cylinder piston into B.viT, the third nMFiy.iijC lJi7 - entering the second cylinder of the first cylinder at the input of the second register of the first pulse (see Fig. 2) On the first output of the latter, a unit 1 signal appears, which arrives and the first input of the third circuit and 13. Since at this moment and earlier the pulses of the first register 18 did not receive any more pulses, it is dropped, and on all its inverse outputs, including the first one, there is a single stenal. Therefore, the appearance of a single sigpa.-ia at the first input of the circuit And 13 leads to unlocking and entering the pulse indication frequency to the indicating unit 16. At the input to the input of the first register 18 T, the first and the um7 from the output de. - has swept 17 frequencies (see FIG. 2) at the first inverse output of this register, the single signal disappears, the third exema.ma coincidence P13 closes, and the passage of the impulses to the display unit 16 stops. Therefore, the leading edge of the pulse is 1; is formed at the time of the start of fuel injection into the second cylinder, and the rear - at the time of the arrival of the piston of the second cylinder in V.IT. This means that the duration of the indicated pulse tii is the fuel injection advance time to the second cylinder, and the NUMBER-10 pulses received at block 16 — the indication — is defined by the expression m-ti3 or taking into account formula (2) In the following manner, W - 3KitKiz-u3 |., ptii ,,,, х „2i -KiKivp / gT, (3) where Qi3 is the HiipiiicKa advance angle of fuel in the second cylinder. Thus, the indications of the indication block 16; are proportional to the measured injection advance angle, and with an appropriate choice of W.-1V, Kj, and Cc express its value either in radians, or in degrees, 1 in, etc.

When the second register Ujo arrives at the input of the second register 19, a single signal appears at its second output, and all the other outputs have zero signals. Since at this point the second pulse has not yet arrived at the input of the first register 18, a single signal acts at its second inverse output, and the appearance of a single level at the output of register 19 leads to unlocking the additional circuit 14 (see Fig. 2) and entering the display 16 of the high-frequency pulses from the output of the controlled oscillator 12. At the time of the arrival of the second pulse at the input of the first register 18, the single signal at its second inverse output disappears, resulting in the AND circuit 14 and the receipt of pulses at the block 16 and Indication stops. Thus, the leading edge of the pulse at the output of the circuit 14 is formed at the moment when the needle of the third cylinder starts to lift, and the rear edge is formed at the moment when the piston of this cylinder approaches the top dead center, and the duration of this pulse is the advance time of fuel injection into this cylinder. By analogy with expression (3), the indications of the display unit 16 are determined by the formula

1M, 4 ZK "Ki014U251, U)

where is the advance angle of fuel injection into the third cylinder. In the interval between the occurrences of the third pulse and the third pulse Ui7, the readings of the display unit 16 are formed, which correspond to the advance angle of injection into the first cylinder, similarly to the above

Ni5 3Ku-Ku6 ,,

where Q is the fuel injection advance angle in the first cylinder.

In the next revolution of the shaft, since triggering the pistons of the first cylinder at TDC, trigger 3 is reset, both registers are set to zero, and the impulse series are not allowed to pass to their inputs — the device is prepared for operation in a subsequent rotation. Therefore, the device measures the lead angle once for two turns of the diesel shaft.

From expression (3) it is easy to get the formula for calculating the number of pulses produced by the controlled generator 12 for one revolution of the shaft, substituting the Qij angle of rotation of the shaft per revolution, i.e. 2U

k1 5KiiK t2 «,,. .. N- - ZKTSK ,,.

From this it follows that a definite number of generator pulses corresponds to a certain angle of rotation of the shaft, regardless of the angular velocity of the shaft. Therefore, when measuring the same injection advance angle at steady-state and transient diesel speeds, the indications of the display unit of this device are the same, which eliminates the measurement error caused by uneven shaft rotation.

Thus, in comparison with the known ones, this device provides a higher accuracy of measuring the diesel fuel injection advance angle in transient high-speed modes of its operation, because when the shaft turns at a certain angle, the controlled generator produces a definite number of pulses regardless of the angular velocity of the shaft, and the readings of the display unit depend only on the actual fuel advance angle on the diesel engine and do not depend on the speed mode at which the measurements are made.

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Claims (1)

DEVICE FOR MEASURING ANGLE OF ADVANCE OF DIESEL FUEL INJECTION, containing the sensors of the studied processes, the first and second pulse shapers, the first, second and third circuit I, the top dead center sensor (TDC), the pulse generator, the first and second registers, the display unit and the trigger, the sensor TDC through the first pulse shaper and the counting input of the trigger is connected in parallel with the first inputs of the first and second circuits AND, the outputs of which are connected to the inputs of the first and second registers, respectively, the second input of the first circuit And is connected to the third input of the third AND circuit, to which the display unit is connected, and the sensors of the studied processes are connected to the second shaper, characterized in that, in order to increase accuracy during transient diesel operation, a frequency divider, OR circuit, and additional I circuits are introduced into the device , the number of which is equal to the number of cylinders, and the frequency to voltage converter, and the pulse generator is controllable, the OR circuit is included in the connection of the sensors of the studied processes with the second shaper associated with the second input of the second circuit And, to which the control input of the pulse generator is connected via a frequency to voltage converter, the output of which is connected to the second input of the first circuit AND, the inverse output of the trigger is connected to the reset buses to the zero state of the first and second registers, the frequency divider is connected to the first circuit And with the first register, the first inputs of the third circuit And and additional circuits And are connected to the direct outputs of the second register, the second inputs of additional circuits And are connected to the second input of the third circuit And, the third inputs of the third circuit And and additional body circuits And are connected to the corresponding inverse outputs of the first register, and the outputs of additional circuits And are connected to the inputs of the display unit.