RU2772629C1 - Analyzer of an inoperable system of a gasoline internal combustion engine, the air-fuel mixture of which is characterized as rich, and its method of application - Google Patents

Abstract

FIELD: internal combustion engines.

SUBSTANCE: Analyzer Faulty System (AFS) is proposed - an analyzer of an inoperative system of a gasoline internal combustion engine (ICE), and a method for its application. AFS includes means for forced sampling of exhaust gases (EG), measurement and indication of voltage about the concentration of hydrogen in the EG. The method for analyzing systems and recognizing an inoperative system is that if the air-fuel mixture is characterized as rich, then, depending on the voltage indicated by AFS, the gas distribution mechanism with a defect, non-optimal valve timing or a gasoline injection system with a defect, a rich mixture or exhaust system, is determined to be inoperative with a defect increased resistance.

EFFECT: creation of analyzer of an inoperative system of a gasoline internal combustion engine.

2 cl, 33 dwg

Description

The field of technology to which the invention belongs

The proposed analyzer of the inoperative Analyzer Faulty System (AFS, English) of a gasoline internal combustion engine (ICE), the air-fuel mixture (FA) of which is characterized as rich (excess air ratio λ < 1; BOSCH. Automobile Handbook. Translated from English. Ltd. " StarSPb "- 3rd ed., Revised and supplemented - M: Book Publishing House Za Rulem LLC, 2012, p. 374), and the method of its application according to class F02B 1/02 of the International Patent Classification IPC-2021 refers to the field of control and technical diagnostics of automobile internal combustion engines with forced ignition, equipped with gasoline injection systems (SIB).

An unauthorized rich mixture reduces the performance of the internal combustion engine, increases fuel consumption and the content of toxic combustion products in emissions. This requires effective measures to achieve the technical result of ICE diagnostics, which consists in a quick and reliable technical diagnosis (GOST 20911-89. Technical diagnostics. Terms and definitions, Table 1, clause 9), based on the analysis of the diagnostic characteristics of the mixture, including qualitative ( signs) and quantitative (parameters) characteristics. The diagnostic features of a rich mixture include black color, the smell of gasoline, particulate matter (PM) of carbon (soot) and a small amount of gaseous and liquid fractions of water vapor in the exhaust gases (EG), black velvety and glossy with the smell of gasoline coating of electrodes and insulators of spark plug electrodes ignition, significant fuel consumption. Values of controlled diagnostic parameters (BOSCH. Automobile reference book, p. 496) (GOST Ρ 7.0.5-2008. System of standards for information, librarianship and publishing. Bibliographic reference. General requirements and compilation rules. Clauses 8.1, 8.2) rich mixtures are distinguished by an increased concentration of carbon monoxide CO, unburned hydrocarbons C _x H _y , carbon C, an underestimated concentration of carbon dioxide CO ₂ , nitrogen oxides ΝΟ _x and oxygen O ₂ ; in addition, the high absolute value of the negative Long Fuel Trim (LFT; URL: https://alflash.com.ua/Learn/ft.pdf), also referred to as the cumulative fuel trim factor (URL: https://scanmatik. ru/downloads/Scanmatik2.pdf) or self-learning correction factor (URL: https://docplayer.com/26092801-M-step-mpi-sistema-mnogotochechnogo-vpryskivaniya-step-ii-mpi.html, pp. 2-18 ).

The peculiarity of the internal combustion engine as an object of diagnostics (OD) is such that various inoperable systems are often characterized by the same diagnostic signs, parameter values and symptoms (subjective sensations of the OD characteristics described by its user). For this reason, ICE diagnostic algorithms have a large number of branches leading to different systems and their components (assemblies and parts), and require a significant amount of time. Therefore, the newly developed diagnostic tools and methods to achieve a technical result should, from the first steps of the algorithm, provide an analysis (separation) of the OD, capable of isolating the one that leads to an inoperable system from the whole variety of branches.

The stereotype of the diagnostic algorithm in the presence of diagnostic signs, parameter values and symptoms of a rich mixture is such that they are perceived as indicating a defect in such a cumbersome system as SRS, as a result of which considerable time is unreasonably spent on the diagnosis of SRS, while in fact they are practically equally inherent in two more ICE systems: the gas distribution mechanism (GRM) of the ICE power unit and the exhaust system.

The timing belt contains one or more intake and exhaust valves per cylinder (hereinafter, for simplicity, the words "intake / exhaust valve" also mean the plural number of valves). OD for the invention is the valve overlap, i.e. the region of the valve timing in the working cycle (RC) of the internal combustion engine, when the intake and exhaust valves of the cylinder are simultaneously open, starting from the phase 10 of the intake valve opening at the end of the exhaust stroke and ending with the phase EC of the exhaust valve closing at the beginning of the intake stroke (BOSCH. Automobile Handbook, p. 414, Fig. 11). Valve overlap is an important factor in gas exchange: it provides the final cleaning of the cylinder with a fresh charge of the mixture, which pushes the combustion products of the previous RC with a volume of V _h / (ε-1) into the exhaust system from the combustion chamber, inaccessible for their expulsion by the piston (V _h - working volume of the cylinder; ε - compression ratio).

Violation of the overlapping phases reduces the time and quality of cleaning the cylinder; part of the PM and internal residual exhaust gases (BOSCH. Gasoline engine control systems. Translated from German C40. 1st Russian ed. - M .: KZHI Za Rulem LLC, 2005, p. 36) remains in the cylinder and on the next RC occupies a certain volume in the cylinder (hereinafter in the text, for simplicity of presentation, “EG” means “PM and internal EGs”). Residual exhaust gases accumulate in the cylinder from cycle to cycle, and the growth of their volume stops when the newly formed cycle volume of exhaust gas becomes equal to the cycle volume of exhaust gas removed from the cylinder. Residual exhaust gases actually reduce the displacement of the cylinder, change the concentration of exhaust gases by participating in chemical reactions, and gradually fill the exhaust system.

A similar process of exhaust gas accumulation in the exhaust system occurs with optimal valve overlap and a stoichiometric (λ=1) mixture, but with increased exhaust system resistance, differing in that exhaust gas initially accumulates not in the cylinders, but in the place of the exhaust system obstruction (blockage), caused by partial or complete destruction of its components such as the body of the catalytic converter (KN) of the exhaust gases, the resonator or the muffler, and, gradually filling the exhaust system, reach the cylinders and fill them.

In both cases, the self-learning (adaptation) system of the electronic control unit (ECU) and the lambda feedback loop of the SVB correct the cyclic fuel dose by the LFT and Short Fuel Trim (SFT) coefficients, however, this does not lead to cleaning the cylinder from the exhaust gas, since the defect is not found. in the SVB, but in the timing or exhaust system.

As a result, improving the means and methods for analyzing ICE systems, the mixture of which is characterized as rich, and recognizing an inoperative system is a very urgent task of achieving a technical diagnostic result.

State of the art

A direct parameter of the valve timing is the angle of rotation of the crankshaft (KB) within the operating cycle. The method of direct measurement of phases includes dismantling the timing and valve covers, spark plugs, manually turning the CV, determining the opening and closing angles of the valves and comparing them with standard phases. Great labor intensity, the absence of a criterion for the optimality of phases and any relation to the exhaust system practically exclude this method from the number of analogues of the invention.

The method of indirect measurement of phases by means of a motor tester (MT) by the pressure of gases flowing in the cylinder is much less laborious, and in this sense is an analogue of the invention. The method includes installing instead of one spark plug a pressure sensor connected to a digital oscilloscope, starting the internal combustion engine, determining the position of the control phases (CF) of the oscillogram of the current pressure in the control sectors (CS) of the phases of the special MT plug-in (URL: https://injectorservice.com.ua /phase_plugin.php etc.). The disadvantages of the method: COP averaged and do not reflect the exact standard values of the phases of the diagnosed internal combustion engine; the optimal values of the phases do not always coincide with the normative ones. Most often, individual CFs are rejected, which does not give grounds for correcting the angular position of the camshaft / shafts; or all CFs are rejected on average by an amount less than the price of one tooth of the drive pulley / sprocket, but there is not enough information to make a decision on phase correction, since correction is possible by an integer number of teeth and not less than one tooth. The practice of using MT gives grounds to assert that if the phase deviates within less than one tooth, this method ensures the accuracy of the technical diagnosis of the timing with a probability P _MT ≤0.8.

The analogues of the invention are means and methods for determining the degree of enrichment of the mixture, indirectly determining the optimality of the gas distribution phase and the normal patency of the exhaust system by the concentration of exhaust gas, determined directly using 2-(CO, CH) and 1-component (CO) automotive gas analyzers (HA), which although they are not informative enough, but due to the affordable price, they are mainly used in service stations and car repair shops, or indirectly by the fuel balance factors LFT and SFT, determined using a diagnostic scanner with such a function. A close to zero LFT value, the compliance of the current SFT values and the exhaust gas concentration with the standard values indicate a stoichiometric mixture, an optimal phase value and a low resistance of the exhaust system and take place with almost complete combustion of the mixture.

The theoretical complete combustion is that the result of the oxidation reaction of hydrocarbons C _x H _y are carbon dioxide CO ₂ and water vapor H ₂ O; for example, a CH ₄ methane molecule and two O ₂ oxygen molecules are converted into a CO ₂ molecule and two H ₂ O molecules (Fig. 1). Taking into account the content of nitrogen N ₂ in the atmospheric air and not taking into account other substances, which in total amount to about 1%, the corresponding concentration of CO ₂ and H ₂ O is formed in the exhaust gas (Fig. 2).

With the almost complete combustion of a stoichiometric mixture, the reactions, in addition to CO ₂ , H ₂ O and N ₂ , are such side exhaust gases as carbon monoxide CO, unburned hydrocarbons C _x H _y and hydrogen H ₂ , excess oxygen O ₂ , nitrogen oxides NO _x , carbon C (Fig. 3), a small amount of sulfur oxide SO ₂ . Exhaust gases removed from the cylinder by a fresh charge of the mixture have the same composition and concentration.

The advantages of analogues are that the EG concentration is the most important integral indicator of the conversion of the chemical energy of fuel hydrocarbons into the thermal energy of the working fluid, and the methods do not require the dismantling of parts and assemblies, since the GA sampling probe (POS) is easily placed in the rear exhaust pipe, and the diagnostic scanner connected through the diagnostic connector, however, it is often necessary to measure the concentration before the KH through the hole of the previously removed first lambda probe or the technological hole.

The disadvantage of analogues is the reliability of the diagnosis only if the concentration of OG corresponds to the standard values, but any discrepancy is not able to point to a specific inoperative system: SVB, timing or exhaust system.

The prototype of the invention are 4-(CO, CH, CO ₂ , O ₂ ) and 5-component (CO, CH, CO ₂ , O ₂ , ΝΟ _x ) GA (URL: https://www.infracar.ru/products/ group41/; http://www.meta-moscow.ru/ru/store/gazoanalizatory-avtomobilnye/mnogokomponentnye-0-ii-klassa-tochnosti/ etc.), which provide higher information content due to a greater number of combinations of values of the OG components . However, the prototype also does not fully achieve the technical result due to the similarity of the rich mixture values (Fig. 4), the values due to non-optimal valve overlap phases or increased resistance of the exhaust system (Fig. 5), despite the difference in defects. In addition, an obstacle to the mass application of the prototype is its high price.

A common disadvantage of analogs and the prototype is that automotive HA are designed to monitor compliance with environmental standards, so they measure the concentration of only toxic components of the exhaust gas, with the exception of the oxygen concentration necessary to assess the degree of oxidation of hydrocarbons. Having no data on other components, the values of the exhaust gas components indicated by the GA in case of violation of the phases of valve overlap and an increase in the resistance of the exhaust system are most often regarded as enrichment of the mixture and erroneously subjected to diagnostics of the SRB, which leads to unjustified labor costs and hinders the achievement of a technical result. But the defect of the SRB within the basic value of the fuel cycle dose of ±20% can be corrected by the LFT coefficient, and thus “masked”, therefore, in order to detect the enrichment of the mixture, it is necessary to determine the LFT value, and when this is not possible, reset the adaptation to zero (reset the ECU settings to initial values), turn off the lambda probes, then start the internal combustion engine and measure the exhaust gas concentration.

Another serious drawback is that the vast majority of internal combustion engines are not equipped with a selection for connecting the GA to the HP, and since the efficiency of the HP is 97 ... 98% or more (URL: https://eet-msk.ru/posts/12; BOSCH. Petrol engine control systems, p. 356), then the HA indicates significantly increased values of the exhaust gas concentration only if their volume exceeds the capabilities of the HF. For example, if the KN is designed to neutralize carbon monoxide having a concentration of 3.5%, then GA indicates an increase in CO only when this value is exceeded (Fig. 6).

An analogue of determining the increased resistance of the exhaust system is the method of measuring backpressure using a pressure gauge or pressure sensor up to KN at an internal combustion engine speed of 2500 min ^-1 , the readings of which should be no more than 10÷15 kPa (Khrulev A.E. Repair of engines of foreign cars. Production practice . edition - M .: Publishing house "Behind the wheel", 1998, p. 170). The disadvantages of the practical application of the method are the need to remove the first lambda probe from the exhaust system, as well as the low reliability of the diagnosis in "boundary" cases, when the back pressure is about 10 kPa or even less, but nevertheless, the exhaust system is clogged and the resistance of the exhaust system is too high. .

The invention eliminates the disadvantages of analogs and prototype and takes into account the needs of practical diagnostics. The proposed AFS analyzer and the method for recognizing an inoperable internal combustion engine system through it makes it possible to achieve a technical diagnostic result. The AFS analyzer and the method of its use are not known from the prior art, do not explicitly follow from the prior art for a specialist, and can be used in a car service, which is why they are a new, industrially applicable invention with an inventive step.

Disclosure of invention

The essence of the analysis of gasoline ICE systems, the mixture of which is characterized as rich, and the recognition of an inoperative system lies in the implementation of the diagnostic model (GOST 20911-89. Table 1, p. Exhaust gas due to enrichment of the mixture, deviation of the valve overlap phases from the optimal value or increased resistance of the exhaust system.

Since the geometrical dimensions of the cylinder are practically unchanged, with a non-optimal timing phase, the number of residual GO molecules increasing with each RC is located in the cylinder due to a reduction in the distances between them, which are many times greater than the size of the molecules themselves. Residual exhaust gases occupy a certain part of the working volume of the cylinder, which is equivalent to its reduction, lead to an increase in pressure in the cylinder and a decrease in the filling factor. Due to inertia, the ECU takes this into account with some delay (1…3 RC), after which it corrects the coefficients of the short-term SFT and long-term LFT of the fuel balance, maintaining λ≈1 within certain limits.

The process of accumulation of residual EG in the cylinder starts from the 2nd RC and is described by the following mathematical model:

where j=2, 3, …, J is the serial number of the RC;

I _j - the current amount of the injected mixture at the j-th RC;

I _j-1 =I _j +ΔI _j - the current amount of the injected mixture at the (j-1)-m RC;

ΔI _j is the current increment in the amount of the injected mixture at the j-th RC to I _j-1 ;

E _j - the current number of issued exhaust gases at the j-th RC;

E _j-1 =E _j +ΔE _j - the current number of issued exhaust gases at the (j-1)-th RC;

ΔE _j is the current increment in the number of exhaust gas produced at the j-th DC to E _j-1 ;

Z _j is the current amount of residual exhaust gas at the j-th RC;

Z _j-1 =Z _j -ΔZ _j - the current amount of residual EG on the (j-1)-th RC;

ΔZ _j is the current increment in the amount of residual exhaust gas at the j-th RC to Ζ _j-1 ;

k=λ/Φ- overlap coefficient, k=0…1;

ϕ - current valve overlap;

Φ - nominal valve overlap. If we assume that the valve overlap begins 10÷15° before TDC and ends 5÷20° after TDC (BOSCH. Automobile Handbook, p. 393, Fig. 2), then the maximum overlap is Φ=35°. The common pitch of drive pulleys and timing sprockets is 3/8" (9.525 mm), which, with their different diameters, results in the presence of 28÷42 teeth. Given that the pulley / sprocket makes one revolution per 720 ° crankshaft rotation, the price of one tooth is 17, 14÷25.71°.

At maximum overlap and minimum multiple of the tooth phase disturbance:

It is obvious that the first part of the residual EG remains in the cylinder only after the end of the 1st RC (j=1), therefore, in this case Z _j-1 = Z ₀ =0, and from (1):

After a certain number of working cycles, the transient processes of accumulation and correction are practically completed, the cyclic amount of released OG becomes equal to the cyclic amount of newly formed OG. In this case ΔI _j =0, ΔE _j =0, ΔΖ _j =0, I _j-1 =I _j , E _j-1 =E _j , Z _j-1 =Z _j , and from (1):

where:

Built on the basis of (3)...(5) family of curves E _j /I _j (j,k) reflects the ratio of the number of outgoing exhaust gases to the amount of inlet mixture depending on the number of operating cycles and the value of the overlap coefficient (Fig.7).

The family of curves Z _j /I _j (j,k) reflects the ratio of the amount of accumulated residual exhaust gas to the amount of the injected mixture depending on the number of RCs and the overlap coefficient (Fig. 8). For example, if the valve overlap is halved (k=0.5), then already on the 3rd working cycle Z _j /I _j =1, i.e. in fact, the working volume of the cylinder decreases by 2 times, and the engine power decreases by the same amount (BOSCH. Automobile Handbook, p. 436, 437), which is enough for idling, but not for high-quality movement of the car. At k=0.2÷0.3, the engine may stall in 5÷6 RC after starting. Obviously, the curves above the k=0.2 curve are theoretical. They do not show the operation of the internal combustion engine for 10÷40 RCs, but already at the ratio Z _j /I _j ≥4, they reflect its ability to operate only 1÷2 RCs, which is often encountered in practice, i.e. when the starter is cranked, the engine does not start, but only separate flashes in the cylinders take place.

The difference between chemical reactions in a cylinder with non-optimal valve overlap phases and a cylinder with optimal phases is due to the fact that the residual EG and carbon particles C from the previous working cycle in the high-temperature environment of the cylinder actively form new hydrocarbons C _x H _Y , in particular, methane CHd:

CO ₂ ⇒CO + O; 2С+O ₂ ⇒2СО; C + O ₂ ⇒CO ₂ ; H ₂ O + CO⇒CO ₂ + H ₂ ; H ₂ O + C⇒CO + H ₂ ; 2H ₂ O + C⇒CO ₂ + 2H ₂ ; 2H ₂ + O ₂ ⇒2H ₂ O; C + 2H ₂ ⇒CH ₄ ; CO + 3H ₂ ⇒CH ₄ + H ₂ O; CH ₄ + 2O ₂ ⇒CO ₂ + 2H ₂ O; CH ₄ + C + H ₂ ⇒ C _x H _y .

The sum of hydrocarbons of the stoichiometric mixture and newly formed hydrocarbons with non-optimal overlap is accompanied by a lower filling of the cylinders, and the result of combustion is the exhaust gases recorded by the gas analyzer, the concentration of which is almost similar to the exhaust gases of a rich mixture with optimal overlap (Fig. 9, where the superscript indices “st” refer to the stoichiometric mixture , "b" to a partially enriched mixture (λ=0.9), "fp" to a stoichiometric mixture with non-optimal overlap phases). This similarity and partial compensation of power at 0.8<λ<1 due to newly formed hydrocarbons significantly complicate the recognition of the defect.

In the chemical reactions of residual exhaust gases, not only exhaust gases with measured concentrations take an active part, but also hydrogen H ₂ and water vapor H ₂ O, the known concentration values of which could contribute to the recognition of a defect, however, they are not included in the list of exhaust gas components measured by automotive gas analyzers.

An important property of the chemical reaction of hydrogen combustion 2Н ₂ +O ₂ ⇒2Н ₂ O is that it occurs only when the concentration of O ₂ ≥6%, or the concentration of H ₂ ≥4%. Another property is the high stability of O ₂ and H ₂ molecules: when they collide, the chemical reaction of water formation occurs only in the presence of free radicals, in particular, H, O atoms and OH groups as a result of the following sequence of reactions: Η + O ₂ ⇒OH + O ; OH+H ₂ ⇒H ₂ O+H; O+H ₂ ⇒OH+H. The free radicals themselves arise and are continuously formed in the process of ignition and self-sustaining combustion at temperatures above 500 ... 577 ° C, and only in this case a group of two OH atoms meets the H ₂ molecule, which forms water (URL: https: // fb.ru/article/422503/temperatura-goreniya-vodoroda-opisanie-i-usloviya-reaktsii-primenenie-v-tehnike Such conditions occur in the cylinders of internal combustion engines, therefore, as a result of combustion of a stoichiometric mixture with non-optimal valve overlap, it is formed on ΔΗ ₂ O more water vapor than when burning a rich mixture and optimal valve overlap (Fig. 10), which is a diagnostic sign, but it is impractical to turn it into a diagnostic parameter due to the difficulties of taking into account the temperature and humidity of the ambient air, the temperature of the exhaust tract and the water vapor itself, separating H ₂ O into gaseous and liquid fractions.

At the same time, during the combustion of a stoichiometric mixture and non-optimal valve overlap, hydrogen does not have time to accumulate in the high-temperature environment of the cylinder, since it reacts with a sufficient amount of oxygen; as a result, its concentration is ΔΗ ₂ less than when burning a rich mixture and optimal valve overlap (Fig. 10), and this diagnostic feature can be turned into a diagnostic parameter without fundamental difficulties, since it allows the use of hydrogen gas analyzers.

With non-optimal valve overlap, the residual exhaust gas fills not only the cylinders, but also the exhaust system after a certain number of RCs. At idling of the internal combustion engine, the temperature of the KH reaches 370 ° C, and in the movement of the car at engine speeds of more than 2000 min ^-1 635 ... 850 ° С (URL: https://www.drive2.ru/l/480976689719935202/), idling, and due to the inertia of heating the HP and 1÷2 min (depending on the location of the HP) after increasing the speed of the internal combustion engine more than 2000 min ^-1 , hydrogen is not oxidized into HP, and its concentration does not decrease. This feature eliminates the need for labor-intensive hydrogen sampling prior to the VF and enables sampling in the rear exhaust pipe despite the high efficiency of the VF.

With increased resistance of the exhaust system, the exhaust gases first accumulate at the site of blockage and reach the cylinders after a while, the faster, the closer the blockage site is to the ICE power unit. In the cylinders, part of the hydrogen burns out, its concentration drops, and then rises again due to the new filling of the exhaust system. Hydrogen concentration fluctuations with a period of approximately 5–60 s, which change due to the turbulence of the exhaust gas flow and decrease with an increase in the engine speed due to faster filling of the exhaust system, are a diagnostic sign of its increased resistance. The oscillation period is significantly different from that of a lambda circuit equipped with two-point lambda probes, but sometimes such lambda probes should be switched off for the duration of the measurement to increase reliability.

Thus, hydrogen sampling in the rear exhaust pipe at idling of the internal combustion engine and within 1 min after increasing the speed does not introduce errors into the diagnosis of the optimal timing phase and allows you to recognize the increased resistance of the exhaust system, which makes it fundamentally possible to use hydrogen gas analyzers with an indication of its concentration and a forced sampling function to ensure measurement accuracy, similar to an automobile GA. However, the high price of such industrial hydrogen gas analyzers, for example, AVP-01G, AVP-02G (URL: https://www.gazoanalizators.ni/AVP-01G-cena-kupit.html; /AVP-02G-cena-kupit.html), prevents their mass application.

Based on this, the design of an inexpensive analyzer of an inoperative ICE system based on an MQ-8 type hydrogen sensor is proposed (URL: http://www.elechouse.com/elechouse/images/product/Hydrogen%20Sensor%02MQ-8/MQ-8. pdf, etc.) (Fig. 11).

Analyzer AFS 1 (Fig. 12) operates as follows.

The sampling probe 2 is located in the exhaust pipe of the exhaust system 3 of the vehicle with the internal combustion engine idling and the exhaust gas 4 containing hydrogen. The vacuum pump 5, when turned on, creates a vacuum and takes the exhaust gas 4 along the path POS 2, the filter 6, the filter-drier (FVO) 7, the inlet fitting 8, the vacuum pump 5, and creates a stable stream of exhaust gas 4, which accumulate under a certain pressure in the receiver 9 and penetrate to the sensitive element of the hydrogen sensor 10, partially exiting the receiver through the outlet holes and releasing excess pressure. The hydrogen sensor 10, under the influence of the hydrogen present in the exhaust gas, generates an electrical signal of a constant voltage, which is measured by a digital voltmeter 11.

The vacuum pump is powered from a +5 V 12 stabilizer, the hydrogen sensor is powered from a +5 V 13 stabilizer, the voltmeter and stabilizers are powered from the car’s on-board network or another +12 ÷ 15 V DC voltage source. The use of two +5 V stabilizers eliminates influence of the electric motor of the vacuum pump on the hydrogen sensor through the power supply circuits. The circuit is protected from polarity reversal by a safety diode 14. The vacuum pump 5 is turned on by a switch 15 equipped with a turn-on light signaling. The AFS 1 housing has ventilation slots 16 to remove excess exhaust gas and ventilate the AFS cavity after work is completed. Filters 6 and 7 are designed to retain soot and other particles in order to avoid clogging of the vacuum pump and hydrogen sensor. FVO 7, in addition, protects the components of the tract from flooding with H ₂ O vapor condensate. As a sampling probe 2, filters 6 and 7, the corresponding regular components of industrial GA can be used. When standard sampling probe 2, filters 6 and 7 are used as a single path of the GA and AFS, it includes a splitter (tee) 17 for directing the exhaust gas simultaneously to the GA 18 and AFS 1, and check valves 19 (Fig. 13), which provide sampling only from exhaust system 3 and at the same time prevent GA and AFS from sampling each other. As a check valve 17, a two-way valve of the fuel tank ventilation system can be used.

AFS 1 is connected to a +12...15 V power supply via cable 20 and crocodile clips 21 (Fig. 14). The vacuum pump 5 (Fig. 15) is mounted on the cushion 22 and the bracket 23 is fixed to the printed circuit board 24, which also has a stabilizer 12 with a radiator 25, a stabilizer 13 and a hydrogen sensor 10, on which the receiver 9 is tightly fitted. The inlet fitting 8 is connected with vacuum pump 5 vacuum hose 26.

The principle of diagnosis using AFS differs from the prototype in that when the mixture is characterized as rich, forced exhaust gas sampling is carried out from the exhaust pipe at idle speed of the internal combustion engine and 1÷2 min at a speed of 2000÷3000 min ^-1 , and at the same time AFS indicates a constant voltage of more than threshold value, then SRB is inoperable, and its defect is a rich mixture. If AFS indicates a voltage not exceeding the threshold value, then the timing is inoperative, its defect is non-optimal valve overlap phases, and, consequently, valve timing disturbances. If the AFS indicates fluctuations in the voltage amplitude above the threshold value with a varying period from several seconds to several tens of seconds, decreasing with an increase in the engine speed, then the exhaust system is inoperative, and its defect is increased resistance. This analysis of ICE systems by means of AFS and the recognition of an inoperative system provides an appropriate technical diagnosis.

Based on this, the method of analyzing by AFS ICE systems, the mixture of which is characterized as rich, and recognizing an inoperative system is as follows. The technical condition of the internal combustion engine is determined as “inoperable”, the cold internal combustion engine is heated to operating temperature at idle speed, and the voltage due to the concentration of hydrogen in the exhaust gas is measured using AFS. To do this, by means of AFS, forced exhaust gas sampling is carried out in the exhaust pipe of a running internal combustion engine at idle and for 1÷2 min at a speed of 2000÷3000 min ^-1 , since in this case, KH does not reduce the hydrogen concentration, and if AFS indicates a voltage not exceeding the threshold values, then a timing belt with a defect is determined to be inoperative, a violation of the optimal valve timing. If the AFS indicates a DC voltage greater than the threshold value, then the SBC with a rich mixture defect is determined to be inoperable. If the AFS indicates fluctuations in the voltage amplitude above the threshold value with a varying period from several seconds to several tens of seconds, decreasing with an increase in the engine speed, then the exhaust system with a defect of increased resistance is determined to be inoperable. The conclusion about the inoperable system and its defect is reflected in the technical diagnosis.

поэтому применение изобретения совместно с мотор-тестером обеспечивает достоверность диагноза: Ρ=1-(1-Р_MT)(1-P_SFD)=0,98.At a relative humidity of 33÷5%, an exhaust gas temperature of +20÷+50°C and the use of a gas analyzer of accuracy class II, for example, "Autotest" 01.03M, measurement errors δН ₂ = 8% (URL: https://dlnmh9ip6v2uc.cloudfront. net/datasheets/Sensors/BiometricMQ-8.pdf, fig. 4), δCO=6% (URL: http://www.meta-moscow.ru/upload/iblock/777/7775871deccd345259d4d3f9df4bad94.pdf, p. 9) , the probability of a reliable diagnosis by AFS

therefore, the use of the invention together with the motor tester ensures the reliability of the diagnosis: Ρ=1-(1-P _MT )(1-P _SFD )=0.98.

Thus, the properties of the AFS analyzer and the method of its use directly determine the ability of the invention to achieve the required technical result of the analysis of gasoline ICE systems, the mixture of which is characterized as rich, and the recognition of an inoperative system.

Brief description of the drawings

Fig. 1. The result of the oxidation reaction during the theoretical complete combustion of fuel assemblies.

Fig. 2. The concentration of CO ₂ and H ₂ O during the theoretical complete combustion of fuel assemblies.

Fig. 3. Composition of GO during practical combustion of stoichiometric fuel assemblies.

Fig. 4. Composition of EG during practical combustion of rich fuel assemblies.

Fig. 5. Composition of EG during practical combustion of stoichiometric fuel assemblies and violation of phases of overlapping of timing valves or increase in exhaust system resistance.

Fig. 6. CO at the inlet and outlet of the KN, neutralizing the concentration of 3.5% CO.

Fig. 7. The ratio of the amount of exhaust gases to the amount of the injected mixture, depending on the number of work cycles and the value of the overlap coefficient.

Fig. 8. The ratio of the amount of residual exhaust gas to the amount of the injected mixture, depending on the number of working cycles and the value of the overlap coefficient.

Fig.9. Exhaust gas concentration of a rich mixture at optimal valve closing phases and a stoichiometric mixture at non-optimal valve closing phases.

Fig. 10. The concentration of water and hydrogen of a rich mixture at optimal valve overlap phases and a stoichiometric mixture at non-optimal valve overlap phases.

Fig. 11. Sensor MQ-8: 10 - hydrogen sensor; 27 - sensitivity regulator.

Fig. 12.APS. Functional diagram: 1 - AFS; 2 - sampling probe; 3 - exhaust system; 4 - exhaust gas; 5 - vacuum pump; 6 - filter; 7 - FVO; 8 - inlet fitting; 9 - receiver; 10 - hydrogen sensor; 11 - voltmeter; 12 and 13 - stabilizers +5 V; 14 - safety diode; 15 - switch; 16 - ventilation slots.

Fig. 13. Scheme of simultaneous sampling by means of GA and AFS: 1 - AFS; 2 - sampling probe; 3 - exhaust system; 4 - exhaust gas; 6 - filter; 7 - FVO; 17 - splitter; 18 - GA; 19 - check valve.

Fig. 14.AFS. Design, appearance (project): 1 - AFS; 11 - voltmeter; 15 - switch; 16 - ventilation slots; 20 - power cable; 21 - clamps.

Fig. 15.AFS. Design (project): 1 - AFS; 5 - vacuum pump; 8 - inlet fitting; 9 - receiver; 10 - hydrogen sensor; 11 - voltmeter; 12 and 13 - stabilizers +5 V; 15 - switch; 20 - power cable; 21 - clamps; 22 - pillow; 23 - bracket; 24 - printed circuit board; 25 - radiator; 26 - vacuum hose.

Fig. 16.AFS. Schematic electrical circuit: VB - on-board network voltage; VCC1, 2 - stabilized voltage +5 V; D1 - safety diode; S1 - switch; IC1, 2 - voltage stabilizers +5 V; UP1 - vacuum pump; IC3 - hydrogen sensor; IC4 - voltmeter.

Fig. 17.AFS. Practical design, appearance: 1 - AFS; 8 - inlet fitting; 11 - voltmeter; 15 - switch; 16 - ventilation slots; 20 - power cable; 21 - clamps.

Fig. 18.AFS. Practical design: 1 - AFS; 5 - vacuum pump; 8 - inlet fitting; 9 - receiver; 10 - hydrogen sensor; 11 - voltmeter; 12 and 13 - stabilizers +5 V; 15 - switch; 20 - power cable; 23 - bracket; 24 - printed circuit board; 25 - radiator; 26 - vacuum hose; 28 - radiator; 29 - hole.

Fig. 19.AFS. Practical design, +12 V power supply, vacuum pump off: 1 - AFS; 8 - inlet fitting; 11 - voltmeter; 15 - switch; 16 - ventilation slots; 20 - power cable.

Fig. 20.AFS. Practical design, +12 V power supply, vacuum pump on: 1 - AFS; 8 - inlet fitting; 11 - voltmeter; 15 - switch; 16 - ventilation slots; 20 - power cable.

Fig.21. Exhaust gas concentration of a known operable internal combustion engine at idle.

Fig. 22. LFT and SFT coefficients of an efficient internal combustion engine at idle.

Fig. 23. Control phases of gas distribution of a healthy internal combustion engine at idle: 30 - KF of the beginning of the opening of the exhaust valve; 31 - KF of the moment of opening the exhaust valve; 32 - KF opening of the intake valve; 33 - KF closing the intake valve.

Fig. 24. Placement of the sampling probe in the rear exhaust pipe: 2 - POS; 34 - rear exhaust pipe; 35 - exhaust silencer.

Fig. 25. Threshold AFS: 1 - AFS: 7 - FVO; 11 - voltmeter, indication of the threshold value of 0.36 V; 15 - switch.

Fig. 26. Indications of the gas analyzer and AFS with a sharp acceleration of the internal combustion engine: 1 - AFS: 7 - FVO; 11 - voltmeter, reading 4.28 V; 15 - switch.

Fig. 27. Practical diagnostics. Spark plugs of the diagnosed internal combustion engine: 36 - central electrode insulator.

Fig. 28. Practical diagnostics. LFT and SFT coefficients of the diagnosed internal combustion engine at idle.

Fig. 29. Practical diagnostics. Measuring the valve timing of the diagnosed internal combustion engine at idle with a USB Autoscope III motor-tester: 37 - pressure sensor.

Fig. 30. Practical diagnostics. Measurement of the gas distribution phase of the diagnosed internal combustion engine at idle with the USB Autoscope III motor-tester: 30 - phase of the start of the exhaust valve opening; 32 - phase of the moment of opening the exhaust valve; 32 - intake valve opening phase; 33 - the closing phase of the intake valve.

Fig. 31. Practical diagnostics. Gas analyzer readings up to KN.

Fig. 32. Practical diagnostics. Maximum readings AFS: 1 - AFS: 7 - FVO; 11 - voltmeter, reading 1.32 V; 15 - switch.

Fig. 33. Practical diagnostics. Minimum readings AFS: 1 - AFS: 7 - FVO; 11 - voltmeter, reading 0.60 V; 15 - switch.

Implementation of the invention

According to the project (Fig. 12-16), a practical design of the AFS analyzer of an inoperative ICE system (Fig. 17-20) was created and tested. The AFS 1 analyzer (Fig. 17) is made in an oil and petrol resistant plastic case with external components: inlet fitting 8, digital voltmeter 11, power switch 15, power cable 20 with crocodile clips 21.

All components of the through-wiring electrical circuitry (FIG. 16) are located on the top side of the single-sided printed circuit board 24 (FIG. 18). Tests showed the need to install a radiator 28 with an area of 50 cm ² to cool the stabilizer 13. The receiver 9 is made from the body of a disposable medical syringe with a volume of 20 ml with four holes 29 1 mm in diameter evenly spaced around the circumference to release excess pressure. AFS Analyzer Specifications:

Controlled substance hydrogen H ₂

Concentration range, % vol. 0.1÷4

Indication range, V 0÷4.5

Threshold voltage, V 0.2÷0.5

EG relative humidity range, % 33÷85

Measurement error at exhaust gas temperature +5÷-+50°С, % ±18

Measurement error at exhaust gas temperature +20÷+50°С, % ±8

Ready time, min 5

Supply voltage, V +12÷15

Power consumption, not more than, W 9

Case dimensions (length × width × height), mm 134×90×46

Weight, no more than, kg 0.4

Setting AFS before the first start: the rotor of the sensitivity regulator potentiometer 27 of the hydrogen sensor 10 (Fig. 11) is turned clockwise to the extreme position (as far as it will go).

Turning on and warming up AFS. Terminals 20 (Fig. 17) are connected to a DC voltage source +12÷15 V, the black terminal is connected to the "minus" terminal of the source, the red terminal is connected to the "plus" terminal. This turns on the voltmeter 11 (Fig. 19) with a value of 0.00, which after a few seconds rises to 0.70 ÷ 1.10, and then within no more than 4 ÷ 5 minutes decreases to a stable value of 0.08 ÷ 0, 24 depending on the hydrogen concentration in the room, receiver, hydrogen sensor. This means that the hydrogen sensor has warmed up and the AFS is ready to go.

The switching on of the switch 15 and the vacuum pump is indicated by the illumination of the switch (Fig. 20). At the same time, the vacuum pump emits a characteristic sound of its operation, which is amplified if the inlet fitting 8 is briefly closed. When the AFS is placed in an environment with zero hydrogen concentration, the air pumped by the vacuum pump into the receiver and blowing around the hydrogen sensor slightly reduces the voltmeter readings, which indicates about the performance of AFS.

The threshold voltage AFS is determined during the operation of a known working warm ICE on a stoichiometric mixture at idle, having an exhaust gas concentration (Fig. 21) and LFT and SFT coefficients (Fig. 22) or control valve timing (Fig. 23), corresponding to the standard values, for whereupon the sampling probe 2 is placed in the exhaust pipe (Fig. 24), the AFS vacuum pump is turned on by the switch 15 (Fig. 25) and stable readings of the voltmeter 11 are recorded for 1÷2 min. Readings should be 0.2 ÷ 0.5 V, which is taken as a threshold value and recorded on the nameplate located on the bottom of the AFS case. The threshold value of the displayed AFS is 0.36 V.

When the accelerator pedal is pressed sharply, the mixture is enriched for a short time, the hydrogen concentration increases significantly, the readings of the voltmeter 11 should reach the value of 4.0÷4.5 V for several seconds, which corresponds to the CO concentration = 5÷9% and 2÷6%, measured up to and after KN, respectively, increased values of CH and O ₂ , underestimated value of CO ₂ (Fig. 26).

If necessary, AFS is tested on a known working internal combustion engine by changing the timing phase and reducing the patency of the exhaust system. The timing phase is changed by shifting the belt (chain) by 1 tooth. The internal combustion engine is started, at idle the concentrations of CO and CH should increase, but the readings of the AFS voltmeter should not increase more than the threshold value. The internal combustion engine is turned off, the timing phase is returned to its original position, the DTCs are reset, the ECU is adapted and the exhaust system is simultaneously cleaned by the operation of the internal combustion engine at various speeds and a test control trip. The patency of the exhaust system is reduced at the optimum timing phase by closing the exhaust tube with a plug with an adjustable hole. Gradually reducing the hole until the concentration of CO = 4.1÷4.3%, measured to KH, is made sure that the readings of the AFS digital voltmeter exceed the threshold value and oscillate with a varying period from several seconds to several tens of seconds. If necessary, in order to distinguish these fluctuations from the fluctuations due to the operation of the lambda circuit equipped with two-point lambda probes, the lambda probes are turned off for the measurement period.

In practice, the technical result of the analysis of ICE systems, the mixture of which is characterized as rich, and the recognition of an inoperative system, has been achieved, which is demonstrated in the following example. The diagnosed 4-cylinder internal combustion engine has such signs of a rich mixture as black deposits on the insulators of the central electrodes 35 of the spark plugs (Fig. 27) and increased fuel consumption; the value of the diagnostic parameter is a negative LFT coefficient (Fig. 28), which is quite enough to switch to diagnostics with the AFS analyzer. However, for research purposes, the control phases of the timing were determined by the USB Autoscope III motor tester, for which a pressure sensor 37 is screwed into the spark plug socket of the 1st cylinder (Fig. 29). At idling of a warmed-up internal combustion engine, the control phases are in the control sectors (Fig. 30), however, three of the four CFs (31, 32 and 33) are at the boundaries of the control sectors, which can also be the reason for giving rich mixture characteristics and indicates a timing defect. At the same time, such a shift of the CF corresponds to approximately half of the tooth of the camshaft drive pulley and does not give grounds for adjusting the timing, since with a shift of one tooth, the CFs 31 and 32 will shift to the opposite boundaries of the control sectors, and the CF 30 will go beyond the control sector. The EG concentration measured before the catalytic converter also characterizes the mixture as rich (Fig. 31), which gives grounds for diagnosing such a cumbersome system as the injection system. Thus, diagnostic signs and parameters do not indicate the inoperability of one particular system and introduce significant uncertainty, which the AFS analyzer is designed to resolve. The exhaust gas concentration measured in the exhaust pipe has ideal values (Fig. 32, 33), but despite this, the hydrogen concentration in 80 s increased significantly above the threshold value of 0.36 V, which corresponds to 1.32 V (Fig. 32 ), and then within 50 seconds the voltmeter reading dropped to 0.60 V (Fig. 33) and again began to gradually increase. These voltage fluctuations indicate an increased resistance of the exhaust system, and a long period of fluctuations indicates a long-term increase in the hydrogen concentration, which is due to a significant removal of the blockage from the power unit. A technical diagnosis has been determined: the exhaust system is inoperable, the muffler defect is most likely. Indeed, after dismantling the muffler, it was found that its body (partitions and filler) began to collapse. The ideal exhaust gas concentration is due to a reduction in the exhaust gas flow rate and, accordingly, the exhaust gas velocity, which led to a more complete afterburning of the exhaust gas in the catalytic converter.

The obtained practical diagnostic data confirmed the compliance of the technical result with the claimed purpose of the invention: the AFS inoperative system analyzer provides analysis of gasoline ICE systems, the mixture of which is characterized as rich, recognition of an inoperative system and the technical result of determining a reliable diagnosis. It seems expedient to expand the functions and diagnostic capabilities of industrial gas analyzers by improving the design by embedding an internal unit for measuring hydrogen concentration, similar to AFS.

Claims (2)

1. An analyzer of an inoperative system (AFS) of a gasoline internal combustion engine (ICE), the air-fuel mixture of which is characterized as rich, including means for forced sampling of exhaust gases (EG), characterized in that it includes means for measuring and indicating voltage about the concentration of hydrogen in the EG, and when sampling exhaust gas from the exhaust pipe of a heated internal combustion engine at idle and for 1÷2 min at an internal combustion engine speed of 2000÷3000 min ^-1 , the constant voltage indicated by AFS does not exceed the threshold value or exceeds the threshold value, or the amplitude of the voltage exceeding the threshold value oscillates with a period of several seconds to several tens of seconds, decreasing with an increase in the internal combustion engine speed, which ensures the recognition of an inoperative internal combustion engine system, respectively, gas distribution mechanism (timing) with a defect non-optimal gas distribution phase or gasoline injection system (SFI) with a defect rich mixture or exhaust system with a defect personal resistance. 2. A method for analyzing systems of a gasoline internal combustion engine, the air-fuel mixture of which is characterized as rich, and recognizing an inoperative system by means of AFS according to claim 1, which consists in determining the technical state of the internal combustion engine "inoperative", warming up a cold internal combustion engine at idle, forced sampling of exhaust gases from the exhaust pipe at idling and 1÷2 min at an internal combustion engine speed of 2000÷3000 min ^-1 , characterized in that if AFS indicates a constant voltage not exceeding the voltage threshold value or more than the threshold value or voltage amplitude fluctuations above the threshold value with a period from several seconds to several tens of seconds, decreasing with an increase in the frequency of revolutions of the internal combustion engine, then it is determined as an inoperable system, respectively, a timing belt with a defect, a non-optimal gas distribution phase or an SRB with a defect, a rich mixture, or an exhaust system with a defect, increased resistance, and reflect this conclusion in the technical diagnosis.

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