SU1629778A1 - Method for evaluating performance of internal combustion engine and device thereof - Google Patents

Description

one

(21) 4499091/06

(22) 10/28/88

(46) 02.23.91. 9 7

(71) Kuibyshev Institute of Railway Engineers

im.MT.Elizarov

(72) Yu.D.Ermakov and V.P. Krivolapov

(53) 621.436.001.5 (088.8)

(56) USSR Copyright Certificate No. 1029026, cl. G 01 M 15/00, 1983.

USSR Author's Certificate No. 1255889, cl. G 01 M 15/00, 1985.

(54) METHOD FOR ASSESSING THE TECHNICAL CONDITION OF INTERNAL COMBUSTION ENGINE AND DEVICE FOR ITS IMPLEMENTATION

(57) The invention relates to testing of internal combustion engines, in particular, to methods and devices for evaluating the technical condition of engines. The aim of the invention is to expand the functionality of the method and device, consisting in the differential recognition of defects in fuel equipment and cylinder-piston group of diesel engines. The goal is achieved by the method of evaluating the technical condition of the engine, which consists in measuring the angular acceleration of the crank weight within a given range of the angle of rotation of the shaft and comparing the measured value with the reference, supplemented by simultaneously measuring the advance angle and duration of fuel injection, h engine conditions are determined by comparison: -; sets of measured parameters with reference. A device that implements a method for assessing the technical condition of an engine, comprising a crankshaft position sensor 1, an injector process sensor 2, amplifier 3, a display unit 4, is additionally equipped with a filter 5, an A / D converter 6, a programmable setting unit 7, a generator 8 of frequency, element 9, memory register 10, information processing block 11. 2 sec. and 1 z.p. f-ly, 7 ill.

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The invention relates to testing of internal combustion engines, in particular to methods and devices for evaluating the technical condition of engines.

Pel of the invention is an increase in the accuracy of the technical condition, which consists in the differential recognition of defects in the fuel equipment and cylinder-piston group of diesel engines.

FIG. 1 shows a diagram of a device for determining the technical condition of engines; in fig. 2 - signal from the process sensor from lifting and landing the nozzle needle; in FIG. 3, pulses from the second output of the position sensor; in fig. A is the pulse from the first output of the position sensor; in fig. 5 is a signal from the set point of the reference device, which permits the operation of the reference frequency generator and the passage of pulses from the position sensor; in fig. 6 - write pulses to the register, which are fed from the first output of the analog-digital converter to the first input of the register (control input); in fig. 7 - information recorded in the register.

The method is carried out as follows.

When a diesel engine is operating, the angular acceleration of the crankshaft is measured in the period between the start and the end of the fuel injection nozzle. At the same time, the advance angle and fuel injection duration are measured. The combination of these parameters is taken as an indicator of the technical condition of the engine when comparing them with reference values. By the angle of advance and the duration of the injection, the technical condition of the fuel equipment is judged, and by the shape of the acceleration curve, the state of the cylinder-piston group, taking into account the mutual influence of these parameters.

A device for implementing the method comprises a crankshaft angular position sensor 1, a nozzle process sensor 2, an amplifier 3, an indication unit 4, a filter 5, an analog-to-digital converter 6, a programmable setpoint generator 7, a frequency generator 8, element 9, register 10 memory TI, information processing unit 11,

The injector workflow sensor is connected through an amplifier and a filter to the first input of an analog-digital converter, to the second input of which two outputs of the shaft position sensor are connected via a programmable setting point and a reference frequency generator. The programmable setpoint adjuster is also associated with the second output of the information processing unit. The second output of the angular position sensor shaft and the output of the setpoint device are also connected to the inputs of the element I, the output of which, like the outputs of the analog-digital converter, is connected to the inputs of the memory register located at the input of the information processing unit associated with the display unit 0 Device works as follows.

Before diagnosing, position sensor 1 is mounted on the engine and rigidly connected to the engine shaft 5. The position sensor 1 converts rotational motion into electrical impulses, the number of which is proportional to the angular / displacement of the shaft. From the second output Q of the sensor 1 position is removed a series of pulses per shaft rotation, from the first output one pulse per shaft rotation. Preliminary on the basis of the engine cyclogram, on, the first input of the setting device 7 from the second output of the information processing server 11, the phases of the beginning and end of the measurement are recorded.

After starting the engine and bringing it to the Q mode, the signal from the sensor 2 of the injector process, the amplitude and shape of which must be measured and analyzed to determine the beginning and end of the fuel supply to the cylinder of the engine,

amplifier 3 passes, filter 5 is fed to the first input of analog-to-digital converter 6. Analog-to-digital converter 6 converts the input analog signal into a digital code proportional to the amplitude of the signal from the rise and fit on the nozzle needle saddle. At the same time, the pulses from the position sensor 1 are fed to the inputs of the setting device 7 and the first input of the element AND 9. The pulse from the first output of the position sensor 1 sets the counting start to the setting device 7, which counts the pulses from 5

Stepping from the second output of the sensor 1 position.

The measurement starts when the number of incoming pulses from the second output of the position sensor 1 to the third input of the setting device 7 and the numerical code corresponding to the phase of the beginning of the fuel supply by the high-pressure fuel pump, i.e. before starting the nozzle needle and fuel supply to the engine cylinder. At this moment, from the output of the setpoint generator 7, one of the inputs of the element I 9 receives a signal permitting the passage of pulses from the second output of the sensor 1 to the third input of the register 10. With this signal, the control unit 7 allows the generator 8 to operate the reference frequency, which delivers high frequency pulses to the second input of the analog-to-digital converter 6 to start it.

The frequency of the impulses of the reference generator 8, i.e. gating frequency of analog-digital converter 6 is selected according to the Kotelnikov theorem

At 1/2 fc,

where it is the maximum interval between samples, in which it is possible to accurately recover the discretized function x (t) from discrete samples,

fc- cutoff frequency, i.e. maximum frequency in the input signal spectrum.

At the end of each conversion, the first output of the analog-to-digital converter 6 is supplied with a write signal at the first input of the register 10. On the front of this signal, a record is written into the register 10 from the second and third inputs. In the register bits 10, a code representing the numeric equivalent of the signal from the sensor 2 of the process 2 is recorded at the second input, where n is the number of bits of the analog-digital converter 6. At the same time, the angular position information is written to the n + 1 bits of the register 10 signal from sensor 2 of the process, i.e. information on the presence or absence of a signal from position sensor 1

6297786

(Fig.2-7) f where the dot indicates the information recorded in the n bits of the register at the second input, the cross indicates the information in n + 1 of the register de 10, recorded at the third input of the register, i.e. the presence of a logical unit. Due to the uneven rotation of the shaft, even within one revolution, the period of the pulses is different.

Thus, information about the process from sensor 2 of the process is linked to II.

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To the phase position of the shaft, and since the gating of the analog-to-digital converter 6 is performed by a constant frequency of the reference frequency generator 8, time information is also linked from the sensor 2 of the process.

Consequently, information about the process from the output of the register 10 is fed to the input of the information processing unit 11 tied to the phase of the motor shaft. Information processing unit 11

25 reads this information and stores until the end of the measurement.

The measurement ends when the number of pulses arriving at the third input of the setting device 7 coincides, and

30 numeric code corresponding to the process of calming down the process of landing the nozzle needle on the saddle.

After the measurement is completed, the information processing unit 11 analyzes the semi-computed information, calculates the feed angle and duration of the injection, the angular acceleration of the crankshaft at the angular interval from injection to the end, compares with the reference ones, and displays the results of the diagnostics 4 on the display 4. The proposed method for assessing the technical condition of an internal combustion engine and the device for its implementation allows it to be used for diesel engines with different crank positions, crankshaft, and also to differentiate defects of fuel equipment and cylinder-piston group, which could not be done using only angular accelerations of the crankshaft.

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Claims (3)

1. A method for evaluating the technical condition of an internal combustion engine, consisting in measuring the angular acceleration of the crankshaft within a predetermined range by the angle of rotation of the stool into the compression cone - the beginning of the expansion stroke and comparing the measured value with a reference one, characterized in that, in order to improve the accuracy technical condition estimates, the angular acceleration is measured in the range of the angle of rotation of the shaft from the beginning to the end of the injection, at the same time, the angle of advance and continuous The search for fuel, and the indicator of the technical condition of the engine is determined by comparing the set of measured parameters with the reference ones. 2. A device for evaluating the technical condition of an internal combustion engine, comprising a crankshaft position sensor with two outputs, a series-connected nozzle working sensor and an amplifier, a display unit, characterized in that, in order to improve the accuracy of the technical condition assessment, it additionally contains a filter, analog-to-digital converter with. two inputs and two outputs, programmable zl sensor with three inputs and one output, reference frequency generator, about 6297788 element I, memory register with three inputs and one output, information processing unit with one input and two outputs, the output of the amplifiers through a filter connected to the first input of the analog-digital converter, the second input of which is connected via the reference frequency generator to the output jQ home of the programmable setting device; the second output of the information processing unit is connected to the first input of the setting device; the second and third inputs of the setting device are connected respectively to the first and fifth outputs of the sensor of the working process of the nozzle, output of the setting device Chen also to one input of the AND member, the other input of the AND output connected to the second 20 of the workflow sensor, the output of the AND element is connected to the third input of the memory register, the first two inputs of which are connected to the outputs of the analog-digital converter, the output of the memory register is connected to the first input of the information processing unit, and its output is connected to the input of the display unit . 3. The device according to claim 2, about tl and 30 such that 3RN is used as the information processing unit FIG. 2