RU2078324C1 - Method and expert system for checking condition of internal combustion engines - Google Patents

Abstract

FIELD: mechanical engineering; internal combustion engines. SUBSTANCE: method is based on continuous measuring of actual values of crankshaft angular acceleration in phase, generating functions of acceleration inertia component and coupling active forces in cylinder with torque, separating acceleration component reflecting working processes in cylinder, calculating indirect indicator diagram of cylinder, comparing it with standard diagram inherent to engine in good repair and with dependence of changes of the diagram at changed in engine condition, and classification of engine condition basing on proximity of actual and standard indicator diagrams. Expert system includes system for registration and processing of indicator diagrams containing cylinder pressure sensors, amplifiers with zero line correction, analog-to-digital converters, angle label sensor with revolution recorder, control unit, threshold flip-flop, manual control unit, receiver, computer, digital indicator, output unit, clock pulse generator, timing pulse distributor, processing algorithm setter, processing command shaper, switch, calculating unit and correcting pulse shaping circuit and additional angle label-spike sensor, spike shaper, OR element, fuel injection sensor, injection amplifier, second threshold flip-flop, twin digital differentiator, digital sign discriminator, acceleration extremum meter, acceleration memory, arithmetic unit, function generator, identification unit, process model setter, condition classification unit, parameters change function setter. EFFECT: simplified and reduced labor input in checking condition of engines in service by indirect finding of cylinder indicator diagrams which does not require installation of special high temperature sensors and special cylinder head, improved accuracy of identification and classification of conditions. 3 cl, 4 dwg

Description

 The invention relates to measuring technique, in particular to determining the technical condition by measuring the pressure in the cylinders of reciprocating internal combustion engines (ICE) in operating conditions.

 There is a method for determining the technical condition of an internal combustion engine by finding the dependence of the indicator pressure in the cylinder on the angle of rotation of the crankshaft [1] from the measured torque, based on the functional dependence of the component of torque, which is determined by the working processes in the controlled cylinder, with the pressure in the combustion chamber of this cylinder.

 The disadvantage of this method is the complexity caused by the need to install in the gap of the power circuit of torque meters (dynamometers).

 There is also a method of determining the technical condition of the internal combustion engine [2] by determining the indicator diagram, which is the prototype of the proposed method and consists in measuring the change in the kinetic energy of the crankshaft depending on the change in the instantaneous values of the rotational speed during the compression stroke and compare it with the reference dependence for serviceable normal engine. The well-known equation of coupling determines the pressure in the cylinder.

 The disadvantage of this method is the complexity caused by the need to install breakers in the power circuit of energy meters, the low accuracy of the classification of the technical condition due to the impossibility of the rapid use of knowledge about the change in the measured process in the zones of normal, permissible and limit state of the engine.

 A known system for recording and processing indicator charts [3] containing pressure sensors in the cylinders with amplifiers and analog-to-digital converters, an angle mark sensor with a turn indicator, a control unit, a threshold trigger, a manual control unit, a receiver, an electronic computer, a digital indicator and an output unit, the outputs of the angle mark sensor being connected respectively to the first and second inputs of the control unit, the third input of which is connected through a threshold trigger to the output of one of the amplifiers, h the fourth input of the control unit is connected to the manual control unit, the fifth input is connected via a receiver to the computer, the first input of the control unit is connected to the first input of the digital indicator and the first input of the output unit, the output of which is connected to the computer, and the second output of the control unit is connected to the control inputs of the analog -digital converters.

 The disadvantage of this system is the inability to pre-register large arrays of sequential indicator charts when testing the engine in real time on non-stationary modes.

 Also known is a system for recording and processing indicator charts [4] comprising pressure sensors in cylinders with amplifiers and analog-to-digital converters, an angle mark sensor with a turn indicator, a control unit, a threshold trigger, a manual control unit, a clock generator, a clock distributor, a clock processing algorithms, processing command generator, switch, computing unit, correction pulse generation circuit, receiver, electronic computer, digital indicator and output unit moreover, the outputs of the angle mark sensor are connected respectively to the first and second inputs of the control unit, the third input of which is connected via a threshold trigger to the output of one of the amplifiers, the fourth input of the control unit is connected to the manual control unit, the fifth input is connected through the receiver to an electronic computer, the first output of the control unit is connected to the first input of the digital indicator and the first input of the output unit, the output of which is connected to the electronic computer, and the second output of the control unit is connected inen with control inputs of analog-to-digital converters, the third output of the control unit is connected to the first input of the computing unit, the fourth output is connected to the correction inputs of the amplifiers through the correction pulse generation circuit and to the first input of the processing instruction generator, the second input of which is connected to the output of the processing algorithms output the receiver, and the third input with the first output of the computing unit, the second output of the control unit is connected to the first input of the clock distributor, the second input of which connected to the clock generator, and the output of the clock distributor is connected to the fourth input of the processing instruction generator and the control input of the switch, the remaining inputs of which are connected to the outputs of the analog-to-digital converters, the output of the switch is connected to the second inputs of the output unit and the computing unit, the third input of which is connected to the output of the processing command generator, into the fourth input to the first output of the control unit, the second output of the computing unit is connected to the second input of the digital indicator and the third input of the output block; the control unit is made in the form of signal generators of angle marks, turnover and the beginning of the cycle, driver of control commands, counter of the current angle, election block, period divider and element And, the first input of the control unit is the input of the signal generator of corner marks, the output of which is connected to the input of the divider period, and the second input of the control unit is the input of the shaper of turn signals, the input of which is connected to the first output of the shaper of the beginning of cycles, the second input of which is the third m is the input of the control unit, and the output of the signal generator of the beginning of the cycle is connected through the counter of the current angle to the output of the election block and the first input of the driver of control commands, the output of the counter of the current angle is the third output of the control unit, the output of the period divider is connected to the third input of the signal generator of the beginning of the cycle, the second the counter input of the current angle, the second input of the control command generator, the third and fourth inputs of which are the fourth and fifth inputs of the control unit, respectively, and the output of the control command generator is connected to the first input of the And element, the second input of which is connected to the output of the period divider, the output of the And element is the second output of the control unit, the first and fourth outputs of which are the second output of the control command generator and the output of the election block, respectively; the computing unit is made in the form of an extremum selection circuit, a period meter, a digital differentiator, an average indicator pressure calculation unit and a parameter register unit, the third input of the computing unit being the first control input of the registers and the first input of an extremum selection circuit, a digital differentiator, a period meter and a calculation unit average indicator pressure, the outputs of which, as well as the first and second inputs of the computing unit are connected to the information inputs of the register unit, The second input of the computing unit is the second input of the extremum selection circuit, the digital differentiator and the average indicator pressure calculation unit, the third input of which is the output of the register unit, the fourth input of the average indicator pressure computing unit is the first input of the computing unit, and the output of the digital differentiator is connected to the fourth input of the circuit selecting an extremum whose second output is the first output of the computing unit, the second output and the fourth input of which are respectively venno output and a second control input of the register block.

 The disadvantage of this system is the difficulty of its application in operating conditions, due to the need to use pressure sensors in the engine cylinders. This can be done only by installing instead of the standard special cylinder head with valves for installing pressure sensors. In addition, the known system is characterized by low accuracy and high complexity in identifying the measured data and assigning the engine to a certain class of conditions, since these operations are carried out manually.

 The objective of the proposed technical solution is to simplify, reduce the complexity and improve the accuracy of classification when determining the technical condition of internal combustion engines in operating conditions.

 The proposed technical solution in comparison with the prototype allows to simplify and significantly reduce the complexity of the examination of the technical condition of the engine by indirectly determining the indicator diagrams of the cylinders by eliminating the need to install special pressure sensors operating at high temperature and a special cylinder head. In addition, the proposed technical solution allows to increase the reliability of determining the technical state of the internal combustion engine due to a more accurate identification of data and classification of states. Compared to the basic object, cylinder indexing using pressure sensors, the complexity of determining the technical condition of the engine is reduced by 8 10 times.

 The problem in the method is solved by rolling the engine at a speed below the minimum idle speed, continuously measuring the angular acceleration of the crankshaft, determining the moments when this acceleration passes through zero from minus plus, and finding angle marks closest to the specified transition moments that take for the conditional top dead center points of the cylinders, then at the rotational speed at which the indicator diagrams of the cylinders are supposed to be determined, the engine is scrolled and the amplitude of the unequal is measured the suspended inertial component of the angular acceleration of the crankshaft fully load the engine at this frequency and continuously measure the angular acceleration of the crankshaft, identify one of the cylinders by the moment of fuel injection, generate the first function of the unbalanced inertial component of the angular acceleration with an amplitude equal to the measured as well as a second function linking the forces acting in the crank mechanism, with the engine torque and in the angular In an interval equal to or less than the engine cycle before and after the conditional top dead center of the cylinder being monitored, it is continuously subtracted in the phase from the measured acceleration of its value at the conditional dead point, the first function is subtracted in the same way, the ratio of the obtained difference and the second function, the obtained dependence on the rotation angle, are found from time to time, they are taken as an indirect indicator diagram of the engine cylinder, compares this diagram and its numerical indicators with standard ones, previously measured and correlated with the same values for the pressure in the cylinder normal serviceable engine, as well as preformed dependency of these quantities changes when changing from the normal state of the engine and to an acceptable limit and the degree of their proximity classified condition of the engine.

 The goal in the expert system is achieved by the fact that an angle tooth sensor, a tooth pulse shaper, an OR cycle element, a fuel injection sensor, an injection amplifier, a second threshold trigger, a double digital differentiator, a digital sign discriminator, an acceleration extremum meter are additionally introduced into the known system , acceleration memory, arithmetic device, function generator, identification unit, process model master, state classification unit, steam change function master meters, and the outputs of the angle mark sensor with a turn indicator are connected respectively to the first and second inputs of the control unit, the fourth input of which is connected to the manual control unit, the fifth input is connected through a receiver to an electronic computer, the first output of the control unit is connected to the first input of a digital indicator and the first input of the output unit, the output of which is connected to an electronic computer. The second output of the control unit is connected to the control inputs of the analog-to-digital converters, and the outputs of the pressure sensors in the cylinders through the amplifiers are connected to the corresponding information inputs of the analog-to-digital converters, the third output of the control unit is connected to the first input of the computing unit, the fourth output is connected to the correction inputs of the amplifiers through a circuit for generating correction pulses and to the first input of the processing instruction shaper, the second input of which is connected through the algorithm setter processing with the receiver output, and the third input with the first output of the computing unit, while the second output of the control unit is connected to the first input of the clock distributor, the second input of which is connected to the output of the clock generator, and the output of the clock distributor is connected to the fourth input of the processing instruction generator and the control the input of the switch, the remaining inputs of which are connected to the outputs of the analog-to-digital converters, the output of the switch being connected to the second inputs of the output unit and the computing unit, the third input of which is connected to the output of the processing command generator, and the fourth input to the first output of the control unit. In this case, the second output of the computing unit is connected to the second input of the digital indicator unit and the third input of the output unit. The input of the first threshold trigger is connected to the output of one of the amplifiers, and the output is from the first input of the OR element of the cycle, the output of which is connected to the third input of the control unit. The injection sensor through a series-connected injection amplifier and a second threshold trigger is connected to the second input of the OR element of the cycle, and the sensor of the angle marks of the teeth through the tooth pulse shaper is connected to the sixth input of the control unit, the fifth output of which is connected to the input of the double digital differentiator, the output of which is connected to the first inputs of the digital sign discriminator, the acceleration extremum meter and the acceleration memory, the output of the digital sign discriminator is connected to the seventh input of the block control, and the outputs of the acceleration extremum meter and the acceleration memory are connected respectively to the first and second inputs of the arithmetic device, the second inputs of the digital sign discriminator, the acceleration extremum meter, the acceleration memory, the third input of the arithmetic device, the first inputs of the state identification and classification blocks are connected to the first the output of the control unit, and the third inputs of the acceleration extremum meter, acceleration memory, the fourth input is arif the device, the input of the function generator, the second inputs of the state identification and classification blocks, as well as the first inputs of the process model setter and the parameter change function setter, are connected to the output of the processing instruction generator, the fifth input of the arithmetic device being connected to the output of the function generator, and the output with second inputs computing unit and output unit. The third input of the identification unit, as well as the second inputs of the process model setter and the parameter change function setter, are connected to the output of the computing unit, the fourth input is the output of the process model setter, and the output is the third input of the state classification unit, the fourth input of which is connected to the output of the parameter change function setter and the output is with the fourth input of the output unit, and the sixth output of the control unit is connected to the second control input of the switch.

 In the expert system, the first and second OR elements and the second AND element are additionally introduced into the control unit, the first input of the control unit being the input of the angle mark signal generator, the output of which is connected to the first input of the first OR element, the second input of which is the sixth input of the control unit, and the output is connected to the input of the period divider, the second input of the control unit is the input of the turn signal shaper, the output of which is connected to the first input of the second OR element, the second input of which is gray the input of the control unit, and the output is connected to the first input of the signal generator of the beginning of the cycle, the second input of which is the third input of the control unit, and the output of the signal generator of the beginning of the cycle is connected through the counter of the current angle to the input of the election block and the first input of the driver of control commands, and the output of the counter the current angle is the third output of the control unit. The output of the period divider is connected to the third input of the signal generator of the start of the cycle, the second input of the current angle counter and the second input of the control command generator, the third and fourth inputs of which are the fourth and fifth inputs of the control unit, and the first output of the control command generator is connected to the first input of the first element And, the second input of which is connected to the output of the period divider. The output of the first element And is the second output of the control unit, the first and fourth outputs of which are the second output of the control command generator and the output of the election unit, respectively. The first input of the second AND element is connected to the output of the first OR element, the output of the second AND element is the fifth output of the control unit, the second input is connected to the third output of the control command generator and at the same time is the sixth output of the control unit.

 The computing unit may comprise an extremum selection circuit, a period meter, a digital differentiator, an average indicator pressure calculating unit, and a parameter register block, the third input of the computing unit being the first control input of the register block and the first input of an extremum selection circuit, a digital differentiator, a period meter, and a block computing the average indicator pressure, the outputs of which, as well as the first and second inputs of the computing unit are connected to the information inputs of the register block wherein the second input of the computing unit is the second input of the extremum selection circuit, the digital differentiator and the average indicator pressure calculation unit, the third input of which is the output of the register unit, the fourth input of the average indicator pressure computing unit is the first input of the computing unit, and the output of the digital differentiator is connected with the fourth input of the extremum selection circuit, the second output of which is the first output of the computing unit, the second output and the fourth input of which They are respectively output and a second control input of the register block.

In FIG. 1 shows the diagrams of the working processes of a four-time in-line four-cylinder internal combustion engine ε _к , ε _in , ε _Σ , ε _etc. components of the angular acceleration of the crankshaft: compression, inertia, resultant and thermodynamic, respectively; IV impulses of fuel injection; IZ - pulses of teeth; TDC
impulse TDC, G ₂ (Φ) - the generated function, determined by the design features of the engine; p _to (Φ) indirect indicator diagram of the engine cylinder; curves 1, 2, 3 indicate the diagrams: normal, with extreme early and late extreme values of the angle of advance of fuel supply, respectively.

 In FIG. 2, 3, 4 are functional diagrams of an expert system for implementing the method and its control unit and computing unit, respectively.

 The inventive method is carried out in the following sequence. Scroll the engine at a speed below the minimum idle speed. At this frequency, there are practically no unbalanced inertial forces and the compression forces of compression and expansion are well manifested. The angular acceleration of the crankshaft is continuously measured, the moments of the transition of this acceleration through zero from minimum to plus are determined (Fig. 1, a), angular marks are found that are closest to the indicated transition moments (in Fig. 1, b they are marked in bold), which are taken as conditional TDC. These angle marks can be obtained from the flywheel tooth sensor or from any other angle mark sensor with sufficient resolution for the angle of rotation. Then, at the speed of rotation at which the indicator diagram is supposed to be determined, the engine is scrolled and the amplitude of the unbalanced inertial component of the angular acceleration of the crankshaft is measured (Fig. 1, e).

где J_д приведенный момент инерции двигателя (среднее значение);
М_ин инерционная составляющая крутящего момента;
ω угловая скорость;
v угол поворота коленчатого вала (ПКВ);
m приведенная неуравновешенная масса (поршня и части шатуна);
r радиус кривошипа;
i_ц число цилиндров;

L длина шатуна.The unbalanced inertial component of angular acceleration is deterministic and completely depends on the layout and inertial properties of the engine. For example, for a four-stroke in-line four-cylinder engine, the second harmonic of the rotational speed is unbalanced (Fig. 1, d);

where J _{d the} reduced moment of inertia of the engine (average value);
M _Institute inertial torque component;
ω angular velocity;
v angle of rotation of the crankshaft (PCV);
m reduced unbalanced mass (piston and connecting rod parts);
r crank radius;
i _{c the} number of cylinders;

L connecting rod length.

 The amplitude of this inertial component depends on a number of factors of a random nature (the mass spread of the flywheel, pistons, connecting rod, balancing mechanism, length of the connecting rod, etc.). However, for a particular engine in this state, its value is constant.

 Then the engine is loaded and the angular acceleration of the crankshaft is continuously measured (Fig. 1, e). Identify the controlled cylinder at the time of fuel injection nozzle. The injection pulse can be obtained from an overhead sensor mounted on a high pressure fuel line of a controlled cylinder, or built into the gap of a fuel line (for example, from a strain gauge, piezo, thermo, or vibration transducer).

где β = arcsin (λsinΦ);
T $\genfrac{}{}{0ex}{}{\text{к}}{\text{i}}$ , T $\genfrac{}{}{0ex}{}{\text{г}}{\text{i}}$ , T_j соответственно компрессионная, газовая, и инерционная составляющая сил, действующих в КШМ;
D диаметр поршня;
P $\genfrac{}{}{0ex}{}{\text{к}}{\text{i1}}$ , P $\genfrac{}{}{0ex}{}{\text{г}}{\text{i1}}$ компрессионная и газовая составляющие давления в цилиндре.After that, the first function τ ₁ (Φ) of the unbalanced inertial component of the angular acceleration (1) with the amplitude A _n equal to the measured one, as well as the second angular acceleration function, which is determined by the structural kinematic features, are generated with reference to the PCV angle (for example, to the TDC of the first cylinder) controlled engine. The unbalanced inertial component is, as a rule, a certain harmonic of the rotational speed (for example, for a four-cylinder four-stroke in-line engine this is the second harmonic of the rotational speed). The second function Г ₂ (Φ) connects the forces acting in the crank mechanism with the torque of the engine Mi ₁ , created by the work of one cylinder:

where β = arcsin (λsinΦ);
T $\genfrac{}{}{0ex}{}{\text{to}}{\text{i}}$ , T $\genfrac{}{}{0ex}{}{\text{g}}{\text{i}}$ , T _j, respectively, the compression, gas, and inertial components of the forces acting in the KShM;
D piston diameter;
P $\genfrac{}{}{0ex}{}{\text{to}}{\text{i1}}$ , P $\genfrac{}{}{0ex}{}{\text{g}}{\text{i1}}$ compression and gas pressure components in the cylinder.

где M $\genfrac{}{}{0ex}{}{\text{к}}{\text{i}}$ ,M $\genfrac{}{}{0ex}{}{\text{г}}{\text{i}}$ ,M_ин,M_п,M_нт соответственно составляющие крутящего момента: компрессионная составляющая индикаторного момента, газовая составляющая индикаторного момента, инерционная, потерь и нагрузки;
ξ_1m фазовое положение цилиндра в соответствии с диаграммой чередования вспышек (например для четырехтактного четырехцилиндрового двигателя) ξ₁₁=0;ξ₁₂=π;ξ₁₃=3π; ξ₁₄=2π; ε_к, ε_г, ε_ин, ε_п, ε_нг соответственно составляющие углового ускорения: компрессионная, газовая, инерционная, потерь, нагрузки. При этом среднее значение ускорения ε_Σ за цикл работы двигателя равно нулю. С учетом (3)-(6) компрессионная, газовая и термодинамическая (равная их сумме) составляющие давления в контролируемом цилиндре могут быть получены выделением из суммарного ускорения (6) соответствующих составляющих:

Для выделения ускорений ε_к, ε_г и ε_тд необходимо прежде всего из суммарного ускорения ε_Σ (фиг. 1, е) вычесть в фазе инерционную составляющую e_ин= A_nГ₁(Φ) (например для четырехтактного четырехцилиндрового двигателя Г₁(Φ)=sin2Φ), а также ε_п и ε_нг. При данной частоте вращения значение ε_п практически не зависит от угла ПКВ, ускорение ε_нг за время измерений остается постоянным. С учетом того, что в ВМТ ускорение ε_к, ε_г и ε_ин равны нулю, то уровень ε_п+ ε_нг можно определить, измерив ускорение ε_Σ в условной ВМТ v= Φ_вмт, затем вычесть его из каждого текущего значения ускорения ε_Σ (фиг. 1, е). Результирующее ускорение e_тд после вычитания имеет вид (фиг. 1,ж), разделив каждое текущее значение этого ускорения на текущее значение второй функции Г₂(Φ) (фиг. 1,з), получим зависимость P_к(Φ) или от времени (фиг. 1, и), которую принимаем за косвенную индикаторную диаграмму цилиндра двигателя.On the other hand, in accordance with the equation of engine dynamics with uneven rotation under load, the resulting acceleration is:

where M $\genfrac{}{}{0ex}{}{\text{to}}{\text{i}}$ , M $\genfrac{}{}{0ex}{}{\text{g}}{\text{i}}$ , M _in , M _p , M _NT respectively components of the torque: the compression component of the indicator moment, the gas component of the indicator moment, inertia, loss and load;
ξ _{1m the} phase position of the cylinder in accordance with the flash sequence diagram (for example, for a four-stroke four-cylinder engine) ξ ₁₁ = 0; ξ ₁₂ = π; ξ ₁₃ = 3π; ξ ₁₄ = 2π; ε _to , ε _g , ε _in , ε _p , ε _ng respectively the components of angular acceleration: compression, gas, inertial, loss, load. In this case, the average acceleration ε _Σ per engine cycle is zero. Taking into account (3) - (6), the compression, gas, and thermodynamic (equal to their total) pressure components in the controlled cylinder can be obtained by isolating the corresponding components from the total acceleration (6):

To distinguish the accelerations ε _k , ε _g and ε _td, it is necessary, first of all, from the total acceleration ε _Σ (Fig. 1, f) to subtract the inertial component e _in = A _n G ₁ (Φ) in phase (for example, for a four-stroke four-cylinder engine G ₁ ( Φ) = sin2Φ), as well as ε _n and ε _ng . At a given speed, the value of ε _{p is} practically independent of the PCV angle; the acceleration ε _ng remains constant during the measurement. Given that the TDC acceleration ε _k , ε _g and ε _in are equal to zero, the level ε _p + ε _ng can be determined by measuring the acceleration ε _Σ in the conventional TDC v = Φ _bm , then subtract it from each current value of the acceleration ε _Σ (Fig. 1, e). The resulting acceleration e _td after subtraction has the form (Fig. 1, g), dividing each current value of this acceleration by the current value of the second function Г ₂ (Φ) (Fig. 1, h), we obtain the dependence of P _to (Φ) or time (Fig. 1, and), which is taken as an indirect indicator diagram of the engine cylinder.

Previously, for a normal serviceable engine, an indicator diagram of cylinder pressures and also numerical indicators of this diagram (maximum pressure PZ, compression pressure P _c , average indicator pressure Pi, maximum pressure rise rate (dP _i / dΦ) are determined using a sensor installed in the combustion chamber ) max and the corresponding angular positions of these indicators (Φ _z , Φ _c , Φ _dmax )). For the same state, an indirect indicator chart is measured and the indicated numerical indicators obtained in the same way, which are taken as the reference ones, are measured. Preliminarily, the dependence of the change in the pressure indicator diagram and the indirect indicator diagram and their indicated numerical indicators is determined when the state of the engine changes from normal to permissible and limit. These dependencies can be obtained, for example, by conducting accelerated wear tests or a multivariate active experiment, taking into account the change in the most significant factors. In the latter case, these dependences can be described by a quadratic polynomial. In FIG. 1 and shows the change in the indirect indicator diagram when the fuel system is misaligned (curve 1 is the normal state, curve 2 is the late value, and curve 3 is the limit value of the early angle of advance of the fuel supply).

где

вектор i-го измерения испытуемого двигателя;

вектор средних значений признаков модели;
Z число признаков, характеризующих состояний двигателя.Then, the measured indirect indicator diagram and its numerical indicators are compared with the reference ones, as well as with the dependence describing the change in these values when the state of the engine changes from normal to permissible and maximum, and the state of the engine is classified by their proximity. As a measure of proximity, for example, the usual Euclidean distance can be taken:

Where

vector of the i-th dimension of the test engine;

vector of average values of model attributes;
Z is the number of signs characterizing the state of the engine.

в отдельности, так и по всем одновременно. В силу разброса рабочих процессов в цилиндре от цикла к циклу необходимо определять среднее значение расстояния (10), полученное по множеству циклов (100-200), или находить расстояние d для усредненных значений P_ki.The distance d is determined both for the entire indirect indicator diagram and for its numerical indicators. In the first case, the number r is determined by the resolution and the required measurement accuracy and is equal to the number of values (counts) of the indirect indicator diagram taken along the PCV angle with a step equal to the step between adjacent corner marks (flywheel teeth). The distance d can be defined as for each numerical indicator

individually, and for all at the same time. Due to the spread of working processes in the cylinder from cycle to cycle, it is necessary to determine the average value of the distance (10) obtained from the set of cycles (100-200), or to find the distance d for the averaged values of P _ki .

 The condition of the engine can conditionally be divided into classes: normal with a deviation of the pressure diagram of numerical indicators by approximately ± 1% of the nominal values; the maximum permissible when they deviate by 1–5% for the worse — when they deviate in the same direction by 5–15% and pre-emergency when they deviate in the same direction by more than 15% according to the value of the distances from the measured indirect diagram to the reference model and before the models corresponding to the indicated classes, a decision is made on the state of the engine. For example, by the minimum value of the indicated average distance, one can judge whether the engine belongs to this class of state.

The expert system for determining the technical condition of an internal combustion engine (Fig. 2) contains a cylinder pressure sensor 1 ₁ 1 _n , amplifiers 2 ₁ 2 _n with zero line correction, analog-to-digital converters 3 ₁ -3 _n , 4 angle mark sensor with marker turnaround, control unit 5, first threshold trigger 6, manual control unit 7, receiver 8, computer 9, digital indicator 10, output unit 11, clock generator 12, clock distributor 13 clocks, processor 14 of processing algorithms, generator 15 of processing instructions, switch 16, computing block 17, correction pulse generation circuit 18, OR element 19, fuel injection sensor 20, injection amplifier 21, second threshold trigger 22, tooth angle mark sensor 23, tooth pulse generator 24, double digital differentiator 25, digital sign discriminator 26, an acceleration extremum meter 27, an acceleration memory 28, an arithmetic device 29, a function generator 30, an identification unit 31, a state classification unit 32, a process model controller 33, a parameter change function controller 34.

Each of the sensors 1 ₁ 1 _n pressure in the cylinders through amplifiers 2 ₁ 2 _n with zero line correction is connected to its analog-to-digital converter 3 ₁ 2 _n , and the first output of the sensor 4 angle marks with a turn indicator to the second input of the control unit 5. The output of one of the amplifiers 2 ₁ 2 _{n is} connected to the input of the first threshold trigger 6, the fourth input of the control unit 5 is connected to the manual control unit 7, and the fifth input is connected through a receiver 8 to the electronic computer 9. The first output of the control unit 5 is connected to the first the inputs of the digital indicator 10 and block 11 output, the output of which is connected to the computer 9; the second output of the control unit 5 is connected to the control inputs of the ADC 3 ₁ -3 _n . The clock generator 12 is connected to the second input of the clock distributor 13, the first input of which is connected to the second output of the control unit 5. The input of the setter 14 of the processing algorithms is connected to the output of the receiver 8, and the output is to the second input of the shaper 15 of the processing commands, the first input of which is connected to the fourth output of the control unit 5, the fourth input with the output of the distributor 13 clocks and the first control input of the switch 16, the third input with the first the output of the computing unit 17, and the output with the third input of the computing unit 17. The input of the correction pulse generator circuit 18 is connected to the fourth output of the control unit 5, and the output with the correction inputs of the amplifiers 2 ₁ - 2 _n . The output of the OR element of cycle 19, one of the inputs of which is connected to the output of the first threshold trigger 6, is connected to the third input of the control unit 5. The fuel injection sensor 20 is connected through a series-connected injection amplifier 21 and the second threshold trigger 22 is connected to the second input of the OR element of cycle 19. The sensor 23 angle marks of the teeth through the shaper 24 of the pulses of the teeth is connected to the sixth input of the control unit 5. The fifth output of the control unit 5 through a double digital differentiator 25 is connected to the first inputs of the digital sign discriminator 26, the acceleration extremum meter 27 and the acceleration memory 28, the second inputs of which are connected to the first output of the control unit 5. The output of the digital sign discriminator 26 is connected to the seventh input of the control unit 5, and the outputs of the extremum meter 27 and the acceleration memory 28 are connected respectively to the first and second inputs of the arithmetic device 29, the third input of which is connected to the first output of the control unit 5, the fifth input with the output of the generator 30 functions, and the output with the second inputs of the output unit 11 and the computing unit 17. The first inputs of the identification units 31 and classification 32 are connected to the first output of the control unit 5, the second inputs of these blocks, and also the third inputs of the extremum meter 27, the acceleration memory 28, the fourth input of the arithmetic device 29, the input of the function generator 30, the first inputs of the process model generator 33 and the parameter change function generator 34 are connected to the output of the processing command generator 15. The third input of the communication identification unit 31 with the second output of the computing unit 17, the fourth input with the output of the master 33 of the process models, the output with the third input of the classification block 32, the fourth input of which is connected to the output of the master 34 of the parameter change function, and the output with the fourth input of the block 11 output.

 The control unit 5 (Fig. 3) contains a shaper of signals of angle marks, a shaper of 36 signals of revolution, a shaper of 37 signals of the beginning of a cycle, a shaper of 38 control commands, a counter 39 of the current angle, the selective block 40, the divider period 41, the first and second elements And 42 , 43, the first and second elements OR 44 45. The first input of the control unit 5 is the input of the angle mark signal generator 35, the second input of the control unit 5 is the input of the turn signal generator 36, the second input of the cycle start signal generator 37 is third their input control unit 5. The output of the shaper 37 of the beginning of the cycle signals is connected through the counter 39 of the current angle to the input of the electoral unit 40 and to the first input of the shaper 38 of the control commands, and the output of the counter 39 of the current angle is the third output of the control unit. The output of the period divider 41 is connected to the third input of the start signal generator 37 of the cycle, the second input of the current angle counter 39 and the second input of the control command generator 38, the third and fourth inputs of which are the fourth and fifth inputs of the control unit 5, respectively.

 The first output of the control command generator 38 is connected to the first input of the first AND 42 element, the second input of which is connected to the output of the period divider 41. The output of the first And 42 element is the second output of the control unit 5, the first and fourth outputs of which are the second output of the control command 38 and the output of the election block 40. The second input of which element And 43 is connected to the third output of the shaper 38 of the control commands. The output of which And 43 is the fifth output, and the third output of the driver 38 control commands the sixth output of the control unit 5. The output of the angle mark signal generator 35 is connected to the first input of the first OR element 44, the output of which is connected to the input of the period divider 41 and the first input of the second AND element 43. The output of the turn signal generator 36 is connected to the first input of the second OR element 45, the output of which is connected to the first the input of the driver 37 of the beginning of the cycle. The second inputs of the elements OR 44,45 are respectively the sixth and seventh inputs of the control unit 5.

 The computing unit 17 (Fig. 4) contains an extremum selection circuit 46, a period meter 47, a digital differentiator 48, an average indicator pressure calculation unit 49, and a parameter register block 50, the third input of the computing unit 17 being the first control input of the register block 50 and the first the inputs of the extremum selection circuit 46, a digital differentiator 48, a period meter 47, and an average indicator pressure calculation unit 49, the outputs of which, as well as the first and second inputs of the computing unit 17, are connected to information the inputs of the register block 50, while the second input of the computing unit 17 is the second input of the extremum selection circuit 46, the digital differentiator 48 and the digital indicator pressure calculation unit 49, the third input of which is the output of the register unit 50, the fourth input of the average indicator pressure calculation unit 49 the first input of the computing unit 17, and the output of the digital differentiator 48 is connected to the fourth input of the extremum selection circuit 46, the second output of which is the first output of the computing unit and 17, the second output and the fourth input of which are respectively the output and the second control input of the block 50 registers.

 As a fuel injection sensor 20, a strain gauge or vibration transducer mounted with a clip on a high pressure pipe (usually the first cylinder) can be used.

 The second threshold trigger 22 is made similar to the first 6 (according to the Schmitt trigger scheme). As the sensor 23 of the angle marks of the teeth, an induction sensor mounted opposite the gear ring of the engine flywheel can be used. The double digital differentiator 25 can be made in the form of two series-connected digital differentiators with averaging, assembled according to a typical scheme. The sliding averaging time of such a differentiator will be determined by the desired number of angle marks used.

A digital sign discriminator 26 can be performed according to a typical circuit of a comparator of codes of current numbers with zero, and an acceleration extremum meter 27 according to a digital maximum selection circuit (digital peak detector). The storage device 28 consists of a set of registers, the number of which in each set must be at least twice the number of angle marks, and the bit depth is determined by the required accuracy of the acceleration measurement. As an arithmetic device 29, a special processor with hard switched logic can be used. The generator of the function 30 may consist of a set of registers, the number and bit depth of which is determined by the necessary accuracy of the reproduction of the function G ₂ (2). The identification blocks 31 and classification 32 can also be built on processors with hardwired logic. The controller 33 of the processor models and the controller 34 of the parameter change functions comprise sets of registers in which the corresponding numerical values of the models and functions are stored.

 The expert system works as follows. The system provides four operating modes: measuring and registering an indicator diagram of pressure in cylinders, binding, training, measuring and registering an indirect indicator diagram. In this case, the last three modes should be carried out sequentially in order.

When the engine is operating in the mode of measuring and recording the indicator diagram of pressure in the cylinders, the instantaneous gas pressure in the cylinders is converted by pressure sensors 1 ₁ -1 _n pressure to the corresponding voltage, amplified by amplifiers 2 ₁ -2 _n and fed to the signal inputs of the ADC 3 ₁ -3 _n . At the same time, the angle mark signals corresponding to equal changes in the PCB angle in a certain amount per revolution are received from the angle sensor sensor 4 at the first input of the control unit 5; the revolution signal from the sensor 4 is fed to the second input of the control unit 5. In addition, to the third input of the control unit 5, through the OR circuit of cycle 19, a cylinder clock separation signal is received identifying the cylinder number. This signal is generated from the pressure signal received from the output of the selected amplifier 2 to a threshold trigger 6, the response threshold of which is set in such a way as to exclude the effect of interference. The signals of the angle marks are normalized by the duration and amplitude in the driver 35 and fed through the first OR circuit 44 to the input of the period divider 41, the output signal of which corresponds to equal changes in the PCV angle in an amount that increased in accordance with the division factor. The turnover signal is normalized by the duration and amplitude in the shaper 36 and enters through the second OR circuit 45 to the first input of the shaper 37 of the beginning of the cycle, the second input of which receives the signal for separating the clock cycles of the cylinders, and the third input signals the angle marks from the output of the period divider 41. The output signal of the driver 37 of the start of the cycle signal can serve as a pulse to start the cycle of the engine. This signal is fed to the input of the initial installation of the counter 39 of the current angle, the counting input of which receives the signals of angle marks from the period divider 41. The code of the current angle of the PCB from the output of the counter 39 is fed to the first input of the shaper 38 of the control commands and to the input of the election block 40. block, by deciphering the code of the current PCV angle, signals are generated that correspond to individual cylinder strokes and TDC moments, which are fed to the fourth output of the control unit 5 and provide selective operation of the expert system by cylinders. Shaper 38 control commands at inputs 3 and 4 receives commands from block 7 manual control and from computer 9 through receiver 8, the input 2 of it also receives signals of angle marks from the divider 41.

 Based on these signals, control command signals are generated in a digital code, which are transmitted via a common channel from the output of control unit 5 to a digital indicator 10, output unit 11, computing unit 17, acceleration extremum meter 27, acceleration memory 28, arithmetic device 29, generator functions 30, identification blocks 31 and classification 32. Each block has its own address, so that it executes the commands intended for it. In addition, the shaper 38 of the control commands generates a signal to enable the measurement process, which allows the passage of angle mark signals from the period divider 41 through the first element AND 42 to the output 2 of the control unit 5. All these signals allow you to organize the calculation process, control the digital display process, and registration of indicator charts and an array of calculated parameters, i.e. allow the primary processing of indicator charts in real time, data visualization and processing of indicator charts also with the help of computers.

The correction pulse generation circuit 18 generates correction pulses from the dead center signals at a certain point in the cycle time for each cylinder (for example, at the bottom dead center of the compression stroke of a given cylinder). These pulses are fed to the correction inputs of amplifiers 2 ₁ - 2 _n and allow periodic automatic adjustment of the zero line of pressure signals, which improves the accuracy of measurement and calculation of parameters expressed in absolute pressure values (maximum pressure P _z , yes occurrence at the end of the compression stroke P _c , etc.).

The signal received from the output 2 of the control unit 5 starts the ADC 3 ₁ 3 _n , which converts the analog pressure signals in all cylinders to the corresponding digital codes supplied to the signal inputs of the switch 16. In addition, this signal triggers the 13-clock distributor, which generates a series of clock pulses for each cylinder for the period of incoming angle marks, taking into account the order of operation of the internal combustion engine cylinders. The frequency of these clock pulses is determined by the generator of 12 clock pulses, and their number by the processing algorithm.

 The input 1 of the shaper 15 processing commands signals the dead points and clock cycles of the cylinders coming from the output 4 of the control unit 5, the input 2 signals of the processing algorithms coming from the host 14 processing algorithms, the input 3 signals of the moments of extreme values of information signals (for example, the moment of maximum combustion pressure) coming from the output 1 of the computing unit 17, to the input 4 of the clock pulses coming from the distributor 13.

 The setter 14 is a storage device with a number of cells equal to the maximum number of processing cycles. Each cell contains a command, and the sequence of their recording determines the algorithm of the system. The commands in the setter 14 of the processing algorithms are set by a digital code using both hard-wired logic and computer program 9 through the receiver 8.

, максимальное давление P_z, максимальная скорость нарастания давления (dP/dΦ)_max давление в конце такта сжатия P_c, угловые и временные интервалы между ВМТ и положением P_z, P_c и т.д. Кроме того, вычисляются другие общие параметры, в частности период оборота и частота вращения. Расчет параметров для каждого цилиндра осуществляется на тактах "сжатие - расширение".Based on the received signals, the processing command generator 15 generates commands for calculating all parameters of the indicator diagrams for all cylinders in real time in the computing unit 17. For each cylinder, for example, the average indicator pressure is calculated

, the maximum pressure P _z , the maximum pressure rise rate (dP / dΦ) _max pressure at the end of the compression stroke P _c , the angular and time intervals between the TDC and the position P _z , P _c , etc. In addition, other general parameters are calculated, in particular the revolution period and speed. Calculation of parameters for each cylinder is carried out on the cycles of "compression - expansion."

 The calculation process is as follows. After the receipt of the command to turn on in the measurement mode of the indicator diagram, the shaper 15 of the processing commands starts to receive a series of clock pulses of the cylinders. The calculation of all parameters for all cylinders is carried out in each angular count for a given block 5 control discretization by the angle PCV. The formation of processing commands for each cylinder starts from the moment the bottom dead center appears, and the calculation inside one corner interval is carried out sequentially for all cylinders, it is determined by signals from the clock distributor 13. The code of the current PCV angle used in the calculation of the angular parameters is constantly supplied to the computing unit 17 and average indicator pressure. When calculating the parameters of a particular cylinder, information on the current pressure of this cylinder passes through the switch 16 to the computing unit 17. Codes of instantaneous pressure values are supplied to the inputs of a digital differentiator 48, an extremum selection circuit 46, an average indicator pressure calculation unit 49. The current angle code is supplied to the average indicator pressure calculation unit 49 and to the parameter register block 50 and serves to calculate the angular parameters and average indicator pressure .

 The processing commands received at the control inputs 1 and 3 of block 17 in a digital code on a single channel process the incoming information. In block 49, the average indicator pressure is calculated by the method of numerical integration, and in the digital differentiator 48, the derivative of the pressure with respect to the PCV angle. The extremum selection circuit 46 selects the moments of the extreme values of the pressure information signals and pressure derivatives and provides these signals to the output 1 of the computing unit 17 for generating processing instructions.

 In the period meter 47, various time intervals are measured for incoming processing instructions. To implement the algorithm for calculating the parameters, the third inputs of the extremum selection circuit 46, the digital differentiator 48, and the average indicator pressure calculation unit 49 provide information on the corresponding calculation results for this cylinder for the previous angular count from the block 50 of the registers. In each angular count, taking into account the current pressure information supplied to the second inputs of the indicated blocks from a specific sensor by the signal of the distributors 13 clock cycles through the switch 16, the processing is performed according to the specified algorithms for each parameter of each cylinder and the intermediate results are constantly recorded in the block 50 registers.

 The calculation of the parameter values for the cycle of operation of each cylinder is received in the block 50 of the parameter registers, where the values of the entire set of parameters for each cylinder are stored until new values for the next cycle of operation are received. During this time, the control commands received at the second control input of the block 50 parameter registers, the calculated parameters are displayed. The calculation process is repeated in each cycle of the cylinder. When a command is received to turn off the measurement process, the calculation is carried out to the end for all cylinders and the computing unit 17 stores the parameter values for all cylinders for the last cycle. The calculated parameter values can be displayed on the digital display 10 by commands from the control unit 5.

 Various arrays of calculated parameters, as well as indicator diagrams with discreteness in the PCV angle determined by the control unit 5, can be entered into the computer 9 for secondary processing using complex programs, as well as for long-term storage of indicator pattern diagrams corresponding to various classes of ICE states.

Before training an expert system, it is initially necessary to fill the database and knowledge base with the information necessary to ensure the classification of engine conditions. To this end, in the described mode, indicator pressure diagrams are recorded, their particular parameters are calculated, and other necessary technical indicators of the engine are measured or calculated (power, fuel consumption, etc.) and the technical condition of the engine is determined from them. In accordance with the requirements of normative and technical documentation, deviations of parameters from the passport (normal) classify the state of the engine. Various technical conditions of the engine (normal, permissible, limit, etc.) can also be modeled by means of adjustments, replacements of units, parts, etc. After establishing the belonging of the test engine to a specific class of states in the training mode, the indirect indicator diagram is measured and recorded, and its particular parameters are calculated (P $\genfrac{}{}{0ex}{}{\text{to}}{\text{z}}$ , P $\genfrac{}{}{0ex}{}{\text{to}}{\text{c}}$ , (dp / dΦ) $\genfrac{}{}{0ex}{}{\text{to}}{\text{max}}$ and etc.). For an engine with a normal technical condition, this diagram and the indicated parameters are recorded in the controller 33 process models. Indirect indicator charts and their particular parameters are measured and recorded for other predefined technical engine states related to the classes of permissible, limit, preliminary and other engine states. The values of the characteristic points of these diagrams (for example, with a step along the PCV angle of 3 5 ^o ), as well as particular parameters, are recorded in the setpoint 34 of the parameter changing functions. The master 33 together with the block 50 of the registers forms a database, and the master 34 together with the blocks of identification 31 and classification 32 knowledge base of the expert system. When the expert system is operating in the modes of binding, training, measuring and registering an indirect indicator diagram, the input of the expert system receives signals only from the fuel injection sensor 20 and the angle mark sensor 23 of the teeth.

 The expert system works in the binding mode in the following sequence. Scroll the engine at a speed below the minimum idle speed. The signal from the sensor 20 through the injection amplifier 21 is fed to the input of the second threshold trigger 22, in which, when a signal from the sensor 21 exceeds the threshold, a pulse is generated, and the trigger threshold of the trigger 23 is selected so as to exclude the action of interference with a level lower than the amplified signal amplitude sensor 20. The signal from the output of threshold trigger 21 passes through an OR circuit of cycle 19 to the third input of control unit 5. The signal from the sensor 23 of the angle marks of the teeth through the shaper 24 of the pulses of the teeth is fed to the sixth input of the control unit 5, which is also the second input of the first element OR 44. From the output of this element, the formed angle marks in the presence of an enable signal from the shaper 38 of the control commands pass through the second element And 43 to the fifth output of the control unit 5. This enable signal is generated in the shaper 38 of the control commands only in the mode of binding, training and measuring an indirect indicator diagram and is fed to one of the inputs of the second element And 43, as well as to the sixth output of the control unit 5, from where it goes to the second control input of the switch 16, for which it is prohibiting, preventing the passage of any signals through the switch 16. From the fifth output of the control unit, the angle mark signals are fed to the input of a double digital differentiator 25, in which tsya angular acceleration for a repetition of three or more adjacent angle marks. Codes of this acceleration are continuously fed to one of the inputs of the digital discriminator of sign 26. In the binding mode, the second input of this discriminator from the output 1 of the control unit 5 receives a command generated in the driver 38 of the control commands to enable the discriminator to work.

 In the sign discriminator 26, the fluid acceleration codes are compared with zero, and when the signs change from minus to plus from its output to the input 7 of the control unit 5, which is also the second input of the second element OR 45, a pulse with a duration of no more than the interval between adjacent angle marks . An angle mark passed through the driver 37 of the beginning of the cycle, a series of which is fed to the third input of this driver from the output of the period divider 41, is used to start the engine cycle. It corresponds to the TDC of the cylinder on which the fuel injection sensor 20 is installed (usually the first cylinder). The start signal of the cycle from the output of the shaper 37 is fed to the input of the initial installation of the counter 39 of the current angle, the counting input of which receives a series of angle marks from the output of the divider 41 of the period. The generated code of the current PCV angle is supplied to the first input of the control command generator 38 and to the input of the election block 40, in which signals corresponding to the dead spots are generated. The rest of the blocks of the expert system does not participate in this mode, since they do not receive commands to enable operation from the control unit 5.

 Snapping along the PCV angle is saved in the training mode, as well as in the measurement and registration mode of the indirect indicator diagram.

 The expert system in training mode is as follows. After the class of technical state to which the engine under test belongs (for example, “normal state”) is detected in the measurement and registration mode of pressure indicator diagrams in cylinders, an indirect indicator diagram is measured and recorded in the following sequence. Taking into account the angle binding of the control panel, carried out in the binding mode, and also taking into account the control commands received at the inputs 4 and 5 of the control unit 5 from the manual control unit 7 and from the computer 9 through the receiver 8, the control command generator 38 generates control command signals, arriving on a common channel from the output 1 of the control unit 5 to a digital indicator 10, an output unit 11, a computing unit 17, an acceleration extremum meter 27, a storage device 28, an arithmetic device 29, a function generator 30, identification units 31 and classification 32. Ф the trimmer 38 of the control commands also generates signals to enable the measurement process, one of which allows the passage of angle mark signals with a divided period from the divider 41 through the first element 42 to output 2, and the second of the formed angle marks from the output of the first OR 44 through the second element And 43 to the output 5 of the control unit 5.

 The enable signal received from the output 3 of the shaper 38 of the control commands is also sent to the output 6 of the control unit 5. All these signals provide the processes of computing, storing, generating functions, creating databases and knowledge, managing digital displays, recording indirect indicator charts and arrays of calculated parameters, i.e. allow the primary processing of information in real time, their visualization, processing of indirect indicator diagrams using a computer.

 The enable signal from the output 6 of the control unit 5 is fed to the second control input of the switch 16, which in the training and measurement modes of indirect indicator diagrams impedes the passage of signals to the output of the switch 16. The clock generator 12, the clock distributor 13, the processor of the processing algorithm 14, and the command generator processing 15 is similar to working in the measurement mode of the indicator pressure diagrams.

 The signals of the angle marks from the fifth output of the control unit 5 are fed to the input of a double digital differentiator 25, in which the current values of the angular acceleration of the crankshaft are calculated.

 Scroll the engine at a speed at which the indicator diagram is supposed to be determined. By command from the shaper 38 control commands coming from the first output of the control unit 5 to the second (control) input of the acceleration extremum meter 27, the maximum values of accelerations are determined, the codes of which come from the output of the double differentiator 25 to the first (information) input of the extremum meter. The processing of these codes for each cylinder is carried out in the sequence determined by the binding along the PCV angle. It is set by the processing commands coming from the output of the shaper 15 processing commands to the third (command) input of the meter 27 of the extremum of accelerations. The measured extreme acceleration values for each cylinder and their phase position are stored and stored in the acceleration extremum meter 27.

Then the engine is loaded to the rated load and the angular acceleration of the crankshaft, which is output from the double differentiator 25, is fed to input 1 (information) of the acceleration memory 28, in a similar manner. Taking into account the control commands coming from the first output of the control unit 5 to the second (control) input, as well as the processing commands coming from the shaper 15 processing commands to the third (command) input of the storage device 28, accelerations are stored in it in the TDC, and also full or partial memorization of other samples, which is necessary to ensure the operation of the arithmetic device 29. At the same time, in the generator 30 functions, taking into account the binding according to the angle of the control panel by the commands of the shaper 15 processing commands the first function F ₁ (Φ) of the unbalanced inertial component of the angular acceleration of unit amplitude, as well as the second function F ₂ (Φ), determined by the design features of the engine. In the generator 30 functions can be generated functions F ₁ (Φ) and F ₂ (Φ) of various types depending on the layout, type, brand and other features of the engine under test.

 They can also be transmitted in advance to this computer generator 9 through a receiver 8 via a common channel.

Arithmetic device 29 performs computational operations with codes received at information inputs 1, 2, 5, taking into account control and processing commands received at control inputs 3 and 4, respectively. It continuously multiplies the function F ₁ (Φ) by the amplitudes of the inertial acceleration components coming from the acceleration extremity meter 27 in phase: it subtracts from each reference the total acceleration coming from the storage device 28, the acceleration values at the TDC stored in this storage device, and also the current values of the multiplied first function; the resulting difference for each sample is divided by the current values of the second function. The resulting dependencies on the PCV angle or on time are taken as indirect indicator diagrams of the cylinders. From the output of the arithmetic device 29, the codes of indirect indicator diagrams are supplied to the second (information) input of the computing unit 17, in which all parameters of the indirect indicator diagrams are calculated. The operation of the computing unit 17 is similar to its operation in the measurement mode of indicator pressure diagrams. Various arrays of parameters calculated by block 17, as well as indirect indicator diagrams with discreteness in the PCV angle determined by control unit 5, can be entered into computer 9 for detailed secondary processing. In addition, the codes of these signals from the second output of the computing unit 17 are fed to the information inputs of the setter 33 of the process models and setter 34 of the parameter measurement functions. According to the commands coming from the output of the shaper 15 processing commands to the second (control) inputs of these controllers, the codes of the indirect indicator diagram of the standard and its parameters for a normal serviceable engine are recorded. In the setter 33 is stored the model standard of the indirect indicator diagram and its parameters
P $\genfrac{}{}{0ex}{}{\text{to}}{\text{z}}$ , P $\genfrac{}{}{0ex}{}{\text{to}}{\text{c}}$ , (dp / dΦ) $\genfrac{}{}{0ex}{}{\text{to}}{\text{max}}$ and etc.
Then, an engine with another known class of states (permissible) is installed on the test bench or this state is simulated by artificial fault input. In the measurement mode of indicator pressure diagrams, an indicator pressure diagram and its parameters are recorded. This more accurately confirms the class of engine condition. After that, in a sequence similar to the one described above, the indirect indicator diagram and its parameters are again measured, which are supplied by the commands of the command generator 15 to the set point 34 of the parameter measurement functions. In this setter, for each count of the indicator diagram, as well as for its parameters, the equation of transition from one class of states to another is determined. For example, if the engine is tested in only two states: normal and acceptable, then this equation is a straight line equation. To obtain a more accurate transition equation, it is necessary to similarly find intermediate 2 3 points between these classes of states. In this case, the transition equation can be, for example, quadratic.

 The calculated equations of the transition from the normal state to the acceptable class are stored in the setter 34 of the parameter change functions.

 In this sequence, the equations of transition from the class of admissible states to the class of limit states are determined, for which engines with the corresponding state are tested. The obtained communication equations are stored in the host 34 functions of changing parameters. To increase the reliability of the classification, samples of each class of states can be stored in the master 33 of process models. Reference models, reference models and communication equations can be transferred to the computer 9, as well as called from there and transferred to the settings 33 and 34.

 In the state examination mode, if an expert system has been trained for a given engine brand, the indirect indicator diagrams are measured in a sequence similar to that described in the training mode, except that the codes of the measured indirect indicator diagrams and their numerical indicators for the shaper commands 15 processing commands served on the third (information) input of the identification unit 31. In this block, the current codes of the measured indirect indicator diagram and its numerical indicators are compared with the phase-identical values of the codes of the reference model or reference model stored in the master 33 of the process models. The comparison results in the form of a difference of codes go to the classification block 34 at the third information input, which calculates a proximity measure, for example of the form (10), and also taking into account knowledge about the behavior of the engine when its state changes, i.e. transition functions from class to class, stored in the master 34 parameter measurement functions, performs the calculation according to a given decision rule and makes an expert opinion on the belonging of the tested engine to a certain class of conditions. As a decisive rule, for example, the minimum value of the calculated average distance (10) between the measured process and the reference model or reference model can be used, depending on whether one reference model or also reference models are stored in the master 33 of the process models classes. Due to the spread of the parameters of the combustion processes from cycle to cycle, the calculation of the distance (10) in the classification block 32 is carried out over many cycles. Information on the results of the examination can be transferred to a computer 9 to create a dossier for a specific engine, as well as for other more complex computing operations, such as predicting the technical condition of engines.

 The proposed method and expert system for determining the technical condition of the engine can be used both to study the working process of the internal combustion engine and automate the control of its operation mode, and to conduct an examination of the technical condition of the internal combustion engine in production and operating conditions with preliminary training of the expert system. The method and expert system allow you to quickly and accurately get an objective expert opinion on the technical condition of the engine. The expert system provides on-line measurement, processing and registration of large data arrays of a plurality of successively alternating pressure indicator diagrams and indirect indicator diagrams, with visualization of intermediate and resulting data, with the possibility of outputting to a computer and outputting processing results to any output device (digital printing device, display, punch , plotter, etc.). It allows by creating databases and knowledge bases of unlimited volume to use the accumulated intellectual potential of developers, researchers, diagnosticians, and operators to conduct an objective examination of the technical condition of ICE.

Claims (3)

 1. A method for determining the technical condition of internal combustion engines by measuring the parameters of rotation unevenness, scrolling the engine at a speed below the minimum idle speed, continuously measuring the angular acceleration of the crankshaft, determining the moments when this acceleration passes through zero from minus plus and finding the angular marks closest to the indicated transition moments, which are taken as the conditional top dead center points of the cylinders, by identifying one of the cylinders at the time of injection of the top the flow, finding the indicator diagrams of pressure in the cylinders when the state of the engine changes and relating them to some indirect signs, characterized in that at the rotational speed at which it is supposed to determine the indicator diagrams of the cylinders, the engine is scrolled and the amplitude of the unbalanced inertial component of the angular acceleration of the crankshaft is measured , fully load the engine at this frequency and continuously measure the angular acceleration of the crankshaft, generate with reference to the angle of rotation of the crankshaft of the first shaft, the first function of the unbalanced inertial component of angular acceleration with an amplitude equal to the measured one, and a second function is generated that connects the active forces acting in the crank mechanism with the engine torque and in an angular interval equal to or less than the engine cycle before and after of the conditional top dead center of the controlled cylinder, its value is continuously subtracted from the measured acceleration in the conditional top dead center in the conditional top dead center, the first function is subtracted, the relation is obtained of the difference and the second function, the obtained dependence on the angle of rotation or on time is taken as an indirect indicator diagram of the engine cylinder, this diagram and its numerical indicators are compared with the reference ones, previously measured and correlated with the same values for the pressures in the cylinders of a working normal engine, as well as preliminary dependences of the change in these values when the state of the engine changes from normal to permissible and maximum, and according to the degree of their proximity classify the state e engine.  2. An expert system for determining the technical condition of internal combustion engines, containing pressure sensors in the cylinders with amplifiers and analog-to-digital converters, an angle mark sensor with a turn indicator, a control unit, a threshold trigger, a manual control unit, a receiver, an electronic computer, digital indicator, output unit, clock generator, clock distributor, processor of the processing algorithms, shaper of processing commands, switch, computing unit, circuit of its formation correction pulses, and the outputs of the angle mark sensor are connected respectively to the first and second inputs of the control unit, the third input of which is connected through a threshold trigger to the output of one of the amplifiers, the fourth input of the control unit is connected to the manual control unit, the fifth input is connected through the receiver to an electronic computer To the machine, the first output of the control unit is connected to the first input of the digital indicator and the first input of the output unit, the output of which is connected to the electronic computer, and the second output is the unit and the control is connected to the control inputs of the analog-to-digital converters, the third output of the control unit is connected to the first input of the computing unit, the fourth output is connected to the correction inputs of the amplifiers through the correction pulse generation circuit and the first input of the processing command generator, the second input of which is connected through the processor of the processing algorithms with receiver outputs, and the third output with the first input of the computing unit, the second output of the control unit is connected to the first input of the clock distributor, sec the input of which is connected to the output of the clock generator, and the output of the clock distributor is connected to the fourth input of the processing instruction generator and the control input of the switch, the remaining inputs of which are connected to the outputs of the analog-to-digital converters, the output of the switch being connected to the second inputs of the output unit and the computing unit, the third input of which is connected to the output of the processing instruction shaper, and the fourth input to the first output of the control unit, the second output of the computing unit is connected to the second the input of the digital indicator block and the third input of the output block, in addition, the computing block contains an extremum selection circuit, a period meter, a digital differentiator, a block for calculating the average indicator pressure and a block of parameter registers, the third input of the computing block being the first control input of the register block and the first input schemes for selecting an extremum, a digital differentiator, a period meter and a block for calculating the average pressure indicator, the outputs of which, as well as the first and second inputs of the calculator the first block is connected to the information inputs of the register block, while the second input of the computing block is the second input of the extremum selection circuit, a digital differentiator and the average indicator pressure calculation unit, the third input of which is the output of the register block, the fourth input of the average indicator pressure calculation unit is the first input of the computing block, and the output of the digital differentiator is connected to the fourth input of the extremum selection circuit, the second output of which is the first output of the calculator a simulation unit, the second output and the fourth input of which are respectively the output and the second control input of the register block, characterized in that it additionally includes a tooth angle mark sensor, tooth pulse shaper, an OR cycle element, a fuel injection sensor, an injection amplifier, a second threshold trigger, double digital differentiator, digital sign discriminator, acceleration extremum meter, acceleration memory, arithmetic device, function generator, identification unit, task ik process models, a state classification unit, a parameter change function controller, the output of the first threshold trigger connected to the first input of an OR element, the output of which is connected to the third input of the control unit, the injection sensor is connected through a series-connected injection amplifier and the second threshold trigger to the second input of an OR element, and the tooth angle mark sensor is connected to the sixth input of the control unit, the fifth output of which is connected to the double-digit input through a tooth pulse shaper a differentiator, the output of which is connected to the first inputs of the digital sign discriminator, acceleration extremum meter and acceleration memory, the digital sign discriminator output is connected to the seventh input of the control unit, and the outputs of the acceleration extremum meter and acceleration memory are connected respectively to the first and second inputs of the arithmetic device , second inputs of the digital sign discriminator, acceleration extremum meter, acceleration memory, third input arif of the metric device, the first inputs of the identification and classification blocks are connected to the first output of the control unit, and the third inputs of the acceleration extremum meter, the acceleration memory, the fourth input of the arithmetic device, the input of the function generator, the second inputs of the identification and classification of states, as well as the first inputs of the master models of processes and a setter of parameter change functions are connected to the output of the processing command generator, and the fifth input of the arithmetic device is connected nen with the output of the function generator, and the output with the second inputs of the computing unit and the output unit, the third input of the identification unit, as well as the second inputs of the setter of process models and the setter of parameter changing functions are connected to the outputs of the computing unit, the fourth input with the output of the setpoint of process models, and the output with the third input of the state classification unit, the fourth input of which is connected to the output of the setter of parameter change functions, and the output with the fourth input of the output unit, the sixth output of the control unit being connected inen with the second control input of the switch.  3. The system according to p. 2, characterized in that in the control unit containing the signal conditioners of the angle marks, revolution, the beginning of the cycle and control commands, the counter of the current angle, the electoral unit, the period divider and the first element And, and to the first input of the first element And the output of the driver of control commands is connected, the third and fourth inputs of which are the fourth and fifth inputs of the control unit, the first input of which is the input of the signal generator of the angle marks, and the second input is the input of the driver turn signals, the second input of the signal generator of the beginning of the cycle is the third input of the control unit, and the output is connected through the counter of the current angle to the input of the electoral unit and the first input of the driver of control commands, and the output of the current angle counter is the third output of the control unit, the output of the period divider is connected with the third input of the signal generator of the beginning of the cycle, the second input of the counter of the current angle, the second input of the driver of control commands and the second input of the first element AND, connected to the first output of the control command generator, and the output of the first AND element is the second output of the control unit, the first and fourth outputs of which are the second output of the control command generator and the output of the election block, two additional OR elements and a second And element are introduced, and the output of the angular signal conditioner labels is connected to the first input of the first OR element, the output of which is connected to the input of the period divider and the first input of the second AND element, the second input of which is connected to the third the control command generator, the output of the turn signal generator being connected to the first input of the second OR element, the output of which is connected to the first input of the start signal generator, the output of the second AND element and the third output of the processing command generator are the fifth and sixth outputs of the control unit, respectively, and the second the inputs of the first and second elements OR are respectively the sixth and seventh inputs of the control unit.

Images