RU2243529C1 - Device for diagnosis of diesel engine - Google Patents

Abstract

FIELD: manufacture of engines; diagnosis of engines and control of fuel equipment.

SUBSTANCE: proposed device includes rpm sensor and sensor of moment of injection, first and second formers, angular velocity computer units, control unit, arithmetical logic unit and display unit. Rpm sensor is connected via first former with angular velocity computer unit and control unit; injection moment sensor is connected with second former and control unit to whose outputs arithmetical logic unit and display unit are connected. Output of arithmetical logic unit is connected with display unit input and inputs of display unit and arithmetical unit are connected in parallel with output of angular velocity computer unit. Device is also provided with angular acceleration computer unit whose first input is connected to output of angular velocity computer unit and second input is connected to control unit output. Output of angular acceleration computer unit is connected to input of arithmetical logic unit.

EFFECT: enhanced accuracy of measurements; enhanced reliability.

1 dwg

Description

The invention relates to the field of technical diagnostics and can be used for built-in and stationary diagnosis of a diesel engine and adjustment of fuel equipment. A device is known for diagnosing a gasoline engine (see USSR Author's Certificate No. 693385, publ. 10/25/1979). The device contains a speed sensor, a sensor v.m.t. the first cylinder, two signal amplifiers, an angular velocity calculation unit, a comparison unit, and an indication unit.

The disadvantages of the known device are the impossibility of a separate assessment of the technical condition of individual engine systems, as well as the use of this device for diagnosing diesel engines. The closest in technical essence and the achieved result to the proposed device is a diesel diagnostic device containing a speed sensor and an injection torque sensor, first and second formers, angular velocity calculation units, a control unit, an arithmetic logic device and an indication unit, the rotation speed sensor through the first driver, it is connected in series with the angular velocity calculation unit, the control unit, and the injection torque sensor is connected in series with the second by the decorator and the control unit, to the outputs of which an arithmetic logic device and an indication unit are connected, the output of the arithmetic logic device being connected to the input of the display unit, and the inputs of the display unit and arithmetic logic device in parallel connected to the output of the angular velocity calculation unit (see USSR Author's Certificate No. 1255889, published on 09/07/1986).

The disadvantage of this device, adopted as a prototype, is the low accuracy of measurements and the reliability of diagnosis in the free acceleration mode and the inability to localize faults on cylinders in this mode. These shortcomings are due to the selected diagnostic parameters, which are highly dependent on the speed and lack of accuracy, cylinder stability.

The task of the claimed invention is aimed at improving the accuracy of measurements, reliability and reducing the complexity of diagnosing diesel.

The task is achieved due to the fact that in the known device for diagnosing a diesel engine, comprising a speed sensor and an injection torque sensor, first and second formers, angular velocity calculation units, a control unit, an arithmetic logic device and an indication unit, wherein the rotation speed sensor is through the first former connected in series with the angular velocity calculation unit, the control unit, and the injection moment sensor is connected in series with the second driver and the control unit, to the outputs of which the arithmetic logic device and the display unit are connected, and the output of the arithmetic logic device is connected to the input of the display unit, and the inputs of the display unit and the arithmetic logic device are connected in parallel with the output of the angular velocity calculation unit, the angular acceleration calculation unit is introduced, the first input of the angular acceleration calculation unit connected to the output of the angular velocity calculation unit, and the second input to the output of the control unit, while the output of the angular acceleration calculation unit by Valid key to the arithmetic logic unit.

Figure 1 shows a diagram of a device for diagnosing a diesel engine. The device comprises a crankshaft speed sensor 1, a fuel injection torque sensor of a specific engine cylinder 2, a signal shaper of a crankshaft rotation speed sensor 3, a signal shaper of a fuel injection torque sensor 4, an angular velocity calculation unit 5, an angular acceleration calculation unit 6, a control unit 7 , arithmetic logic device 8, display unit 9. The elements are connected in the form of two parallel circuits, the first of which consists of a rotation sensor for the frequency of the crankshaft 1, ph 3 tors, its signal unit 5 calculating the angular velocity, angular acceleration computing 6 unit and a second series connected sensor 2 fuel injection points, the shaper 4 of its signal, the control unit 7. The second input of the control unit 7 is connected to the input of the angular velocity calculation unit 5. The third and fourth inputs of the control unit 7 are respectively connected to the outputs of the angular velocity calculation unit 5 and the output of the angular acceleration calculation unit 6. The first and second outputs of the control unit 7 are connected to the inputs of the arithmetic logic device 8 and the indication unit 9, respectively. The second ones, connected in parallel, are connected to the output of the angular velocity calculation unit 5. The third input of the arithmetic logic device 8 is connected to the output of the block 6 for calculating the angular acceleration. The third input of the display unit 9 is connected to the output of the arithmetic logic device 8.

The device operates as follows. The pulses from the sensor 1 with a frequency corresponding to the angle of rotation of the crankshaft for one tooth of the flywheel of the flywheel, passing through the shaper 3, arrive at blocks 5 and 7. Block 5 measures the repetition period of these pulses and in accordance with the measured on one tooth of the flywheel of the flywheel and measured periodically calculates the angular velocity at a given angle of rotation of the shaft, the values of which are supplied to the inputs of blocks 6, 8 and 9. Block 6, taking into account the period of following these pulses and in accordance with the gear ring of the flywheel per one tooth and and measured angular velocity, as well as the value of the angular velocity attributable to the previous tooth, calculates the angular acceleration at a given angle of rotation of the shaft, the values of which are fed to the input of the arithmetic logic device 8. The signal from the sensor 2 is the moment of fuel injection of a particular cylinder, usually the first, through the shaper 4 is fed to the input of the control unit 7. Block 7 with the arrival of the pulse from the sensor 2 counts the pulses and calculates the angle of rotation of the crankshaft. When the crankshaft is rotated by an angle corresponding to the moment of fuel injection in the first cylinder of the engine, block 7 supplies the first control signal to the input of block 8. Based on this signal, block 8 starts selecting the minimum value of the angular velocity at the beginning of the working stroke in the first cylinder (ε _min1 ) At the same time, block 8 selects the maximum value of the angular acceleration attributable to the first half of the working stroke in the first cylinder (ε _max1 ). When the crankshaft is rotated through an angle of 720 / (3 · i) (where i is the number of engine cylinders) from the top dead center of the compression end in the first cylinder, block 7 provides a second control signal, upon arrival of which block 8 stops selecting the minimum value of the angular velocity and the maximum values of the angular acceleration, stores these values in the memory and switches to the search mode for the maximum value of the angular velocity in the middle part of the expansion stroke (ε _max1 ). At the same time, block 8 selects the minimum value of the angular acceleration attributable to the second half of the expansion stroke in the first cylinder (ε _max1 ).

When the crankshaft is rotated through an angle of 720/1, block 7 provides a third control signal, by which block 8 stops selecting the maximum value of the angular velocity and the minimum value of angular acceleration, and stores these values in memory. At the same time, block 8 starts searching for the minimum value of the angular velocity and the maximum value of the angular acceleration in the next cylinder in order of operation (ε _max1 ). At the end of the measurement cycle, which must reach at least 10 cycles to achieve the required accuracy, block 7 supplies the next control signal to blocks 8 and 9. Based on this signal, block 8 calculates the average value of the increments of the angular velocity from the minimum value (ω _min1 ) to the maximum ( ω _max1 ) per expansion cycle of each cylinder (Δω _i ) decrease in angular velocity from its maximum value for the ith cylinder to its minimum value per expansion cycle in the next cylinder in order of operation, i.e. for a (i + 1) -th cylinder (Δω _i ), similar indicators are also determined by angular acceleration (see Ecology - Health - Life Safety: Materials of a regional scientific-practical conference dedicated to the 60th anniversary of the Kurgan region / Edited by AND .I. Manilo. - Kurgan: Kurgan Scientific Center of the MANEB, 2002. - p.167-169.). Block 8 determines the diagnostic parameters, which are used as the product of increments and decreases by the average values of angular velocities at the corresponding positions of the crankshaft. As well as the increment and decrease of angular acceleration in the corresponding sections.

The calculation results are indicated by the display unit 9. Block 9 also displays the current value of the angular velocity of the crankshaft. Thus, the device allows you to determine the technical condition of the diesel engine according to the indicators of uneven rotation of the crankshaft (parameters for angular velocity and angular acceleration) at idle and free acceleration modes, which allows you to localize typical malfunctions of the diesel engine and its systems, as well as adjust fuel equipment without removing her from the engine.

The use of a device for diagnosing diesel engines in comparison with the prototype will increase the measurement accuracy by 25%, the reliability of the diagnosis by 20% and reduce the complexity by 10%.

Claims (1)

A device for diagnosing a diesel engine comprising a rotational speed sensor and an injection timing sensor, first and second formers, angular velocity calculation units, a control unit, an arithmetic logic device and an indication unit, the rotational speed sensor being connected through the first former in series with the angular velocity calculation unit, unit control, and the injection moment sensor is connected in series with the second driver and the control unit, to the outputs of which an arithmetic logic device is connected and an indication unit, wherein the output of the arithmetic logic device is connected to the input of the indication unit, and the inputs of the indication unit and the arithmetic logic device are connected in parallel with the output of the angular velocity calculation unit, characterized in that an angular acceleration calculation unit is introduced, the first input of the angular calculation unit acceleration is connected to the output of the angular velocity calculation unit, and the second input to the output of the control unit, while the output of the angular acceleration calculation unit is connected to the arithmetic input logical logical device.