RU2691275C2 - Method of determining content of ethanol in fuel using an oxygen sensor (embodiments) - Google Patents

Abstract

FIELD: internal combustion engines.SUBSTANCE: disclosed are methods for accurate determination of variability of readings of oxygen content sensor in inlet air or sensor of oxygen content in exhaust gases. Methods include actuation of oxygen sensor at lower reference voltage, at which water molecules are not dissociated, for generation of first output signal and at higher reference voltage, in which water molecules are completely dissociated to generate a second output signal and finding a correction factor for the sensor on the first and second output signals. Obtained correction coefficient is used to control the transfer function of the alcohol content in order to increase the accuracy of estimating the content of ethanol in the combustible fuel, which improves operational characteristics of the engine owing to improved adjustment of its operating parameters.EFFECT: invention can be used in fuel management systems for internal combustion engines.20 cl, 6 dwg

Description

References to related applications

This application partially continues the application for S.Sh.A. No. 14/151,574 “Method for determination of ethanol content in fuel using an oxygen sensor” registered on January 9, 2014, the content of which is fully and in all respects included in the present invention by reference.

The level of technology

Intake or exhaust gas sensors can be activated to provide an indication of the content of various components of the exhaust gas. For example, in the application S.Sh.A. 20120037134 discloses dilution detection at the engine intake using an intake air oxygen sensor. In alternative approaches, engine dilution can be estimated using an exhaust gas oxygen sensor. Estimated engine dilution can be used to regulate a variety of engine operating parameters, such as fuel supply and air-fuel ratio. Another example is the application of S.Sh.A. 5,145,566, revealing the detection of the water content in the exhaust gases using the sensor oxygen content in the exhaust gases. In alternative approaches using an intake air oxygen sensor, it is possible to estimate the water content in the exhaust gas recirculated to the engine intake (exhaust gas recirculation (EGR)). The water content estimated using the intake or exhaust gas oxygen sensor can be used during engine operation to find the humidity value of the ambient air. In addition, the water content can be used to find the alcohol content in the fuel burned in the engine.

However, the authors of the present invention found that oxygen sensors (both oxygen sensors in the intake air and oxygen sensors in the exhaust gases) can have significant variability in readings. For example, without any compensation, the variability of oxygen measurements by the sensor can reach up to 15%. This variability in the output signal of the sensor can lead to a significant error in the measurement of the alcohol content in the fuel and the dilution in the engine. For example, due to the variability of the sensor, the transfer function of the alcohol content may be changed (used to estimate the alcohol content of the fuel from the output of the oxygen sensor). If we use the known transfer function for a nominal sensor, then the alcohol content in the fuel can be underestimated or overestimated. Therefore, in order to correctly measure the alcohol content in the fuel, it is necessary to compensate for this variability in the readings, which depends not only on the age of the sensor, but also on environmental conditions (in particular, on environmental humidity levels), but also on additional thinners (such as purge or crankcase ventilation).

DISCLOSURE OF INVENTION

The above disadvantages can be dealt with by increasing the accuracy of estimating the alcohol content in the fuel using an oxygen sensor (in the intake air or exhaust gases) by applying a method that better compensates for variability in sensor readings.

One example of the method involves, under selected conditions, activating an oxygen sensor at a lower voltage at which water molecules do not dissociate, to generate a first output signal, and at a higher voltage at which water molecules completely dissociate, second output. The method also includes finding the correction factor for the sensor on the first and second output signals. The method may also include adjusting the parameter for the alcohol content, and the alcohol content in the fuel burned in the engine is estimated as a whole by the first output signal and the correction factor found. Thereby increasing the reliability of the oxygen sensor.

In this method, the parameter may be the desired air-fuel ratio for combustion in the engine.

In this method, the first output signal may include the first pump current generated in response to actuation at a lower reference voltage, and the second output signal may include the second pump current generated in response to actuation at a higher reference voltage tension.

In this method, the first output signal may indicate oxygen content for humid air, and the second output signal may indicate an increase in oxygen content as a result of dissociation of moist air, and the pump current for dry air may be based on the ratio of the first and second output signals, and the pump current dry air can indicate oxygen content for dry air.

In one example, under selected conditions, an oxygen sensor is activated to determine the oxygen sensor readings corrected for dry air conditions. For example, when the purge and crankcase ventilation gases are not fed into the engine intake manifold, it is possible to modulate the reference voltage of the oxygen content sensor in the intake air. Thus, the correction factor may be a correction factor for dry air, compensating for the variability of sensor readings, and finding the correction factor for the first and second output signals may include finding the correction factor based on the ratio of the output signal of the reference sensor to the ratio between the first and second output signals.

In this method, the reference transfer function of the alcohol content of the sensor can be based on the output signal of the reference sensor.

In this method, the estimation of the alcohol content in the fuel, both on the first output signal and on the found correction factor, may include: adjusting the reference transfer function of the alcohol content of the sensor based on the found correction factor; and applying the adjusted alcohol transfer function to the first sensor output.

In this method, the oxygen sensor may be a universal sensor of oxygen content in the exhaust gases associated with the exhaust manifold of the engine upstream of the catalytic converter exhaust gases.

In this method, the conditions selected may include conditions without supplying the engine with fuel, and conditions without supplying the engine with fuel may include the event that the fuel supply is turned off during deceleration.

In this method, the oxygen sensor may be a sensor for oxygen in the intake air associated with the engine intake manifold upstream of the intake compressor.

In this method, the selected conditions may include the inclusion in the work of the EGR and the lack of reception in the intake manifold gases purge or gases crankcase ventilation.

Alternatively, in embodiments where the oxygen sensor is an oxygen sensor in the exhaust gases, the conditions selected may include conditions without fuel supply to the engine, for example, shutting off the fuel supply during deceleration (AT). In particular, the reference oxygen sensor voltage can be raised from the first lower value, at which the output signal (for example, pump current) is an oxygen reading in wet conditions, to the second, higher value, at which output signal (for example, pump current a) sensor characterizes an increase in the oxygen content as a result of the complete dissociation of moisture. Then, based on the ratio of the first and second output signals, you can determine the pump current for dry air, and the pump current for dry air is an indicator showing the oxygen content in dry air. The oxygen content reading for dry air (i.e. the ratio between the first and second output signals) is then used to adjust the transfer function of the alcohol content. Then the corrected transfer function and the reading (first output signal) of the oxygen content for humid air can be used to estimate the alcohol content of the fuel. Estimation of the alcohol content in the fuel can then be used to estimate the engine operating parameter, for example, the air-fuel ratio required for burning the fuel. For example, according to the estimated alcohol content in the fuel, the controller may adjust the air-fuel ratio correction.

Thus, another variant of the method includes, under conditions without supplying the engine with fuel, supplying the sensor with the oxygen content in the exhaust gases of both a first, lower voltage, in which water molecules do not dissociate, and a second, higher voltage, in which molecules the waters completely dissociate. The method also includes finding the correction factor for the sensor based on the ratio of the first and second output signals generated when the first and second voltages are applied, respectively, and estimating the ethanol content of the fuel burned in the engine by applying the found correction factor to the transfer function signal.

In one embodiment of this method, the conditions without supplying the engine with fuel may include the event of shutting off the fuel supply during deceleration, and the method may also include controlling the engine operation parameter based on the estimated ethanol content of the fuel, and the parameter may include fuel ratio for burning.

In another variant of this method, the first output signal may include the first pump current generated in response to the supply of the first, lower voltage, and the second output signal may include the second pump current generated in response to the supply of the second, higher voltage The first and second output signals indicate the amount of oxygen in humid air, and the first, lower voltage is below average voltage, and the second, higher voltage is above average voltage, the average voltage is e generates a third pump current indicating the amount of oxygen in dry air.

In yet another embodiment of this method, an oxygen content sensor in the exhaust gases can be placed upstream of the exhaust catalytic converter and upstream of the EGR channel inlet, configured to recirculate exhaust gas from the exhaust manifold to the engine intake manifold.

Thus, it is possible to more effectively find the variability in the readings of the sensor oxygen content in the intake air or sensor oxygen content in the exhaust gases, including variation due to aging of the sensor. When finding variability eliminates the need to use a compensation resistor, made with the possibility of compensating for variability in the readings, which gives advantages in reducing costs and reducing the number of components. By using an oxygen content estimate for dry air to adjust the transfer function using an oxygen content sensor, it is possible to reduce the irregularities in estimating the ethanol content in the fuel. Increases the reliability of the sensor as a whole. Also increases the accuracy of estimating the alcohol content in the fuel from the output of the oxygen sensor. Due to the fact that the output signal of the sensor and the evaluation of the alcohol content in the fuel are used to control various parameters of the engine, the performance of the engine as a whole is improved.

In another example, the method includes, when gases of purging and crankcase ventilation are not supplied to the engine, supplying the sensor with the oxygen content in the intake air of the first, lower voltage, at which water molecules do not dissociate and the second, higher voltage, at which the waters completely dissociate. The method also includes finding a correction factor for the sensor based on the ratio of the first and second output signals generated when the first and second voltages are applied, respectively, and evaluating the ethanol content of the fuel burned in the engine by applying the found correction factor to the transfer function based on first output signal.

In one embodiment of this method, the first output signal may include the first pump current generated in response to the supply of the first, lower voltage, the first output signal indicates the amount of oxygen in humid air, and the second output signal may include the second pump current, produced in response to the supply of a second, higher voltage, the second output signal indicates an increase in the oxygen content as a result of the dissociation of moisture, and the ratio between the first and second output signals of the MC binds oxygen in the dry air.

In another embodiment of this method, an intake air oxygen sensor may be located upstream of the intake throttle and downstream of the EGR channel exit, configured to recirculate exhaust gas from the exhaust manifold to the engine intake manifold.

In yet another embodiment, the method also includes estimating the EGR flow to the EGR channel based on the adjusted output signal of the oxygen content in the intake air based on the output signal of the oxygen content in the intake air and the correction factor found.

It should be understood that the above brief description is for reference only in a simple form with some concepts that will be described in detail later. This description is not intended to indicate key or significant distinguishing features of the claimed subject matter, the scope of which is uniquely defined by the claims, which follow the section “Implementation of the Invention”. In addition, the claimed subject matter is not limited to implementations that eliminate any disadvantages indicated above or in any other part of the present disclosure. Also, the above results were obtained by the authors of this application and should not be recognized as known.

Brief Description of the Drawings

FIG. 1 schematically shows an engine comprising an oxygen content sensor for exhaust gases and an oxygen content sensor for intake air.

FIG. 2 schematically shows an example of an oxygen sensor.

FIG. 3 shows a flowchart of an algorithm for accurately estimating the amount of alcohol contained in a fuel when adjusting the transfer function of the alcohol content from the effects of varying the oxygen sensor readings.

FIG. 4 shows in the graph the output signals of the oxygen sensor as a function of the applied voltage at different humidity.

FIG. 5 is a graph illustrating the effect of variability in oxygen sensor readings on the evaluation of ethanol content in fuel.

FIG. 6 shows a block diagram of the engine control algorithm for the output signal of the oxygen in the intake air sensor or the sensor of oxygen in the exhaust gases.

The implementation of the invention

The following description relates to a method for determining the amount of alcohol in a fuel mixture (for example, ethanol with gasoline) from the output signals of an intake air sensor or an exhaust gas sensor, such as an oxygen sensor. For example, a sensor may be activated with a first, lower voltage applied to produce a first output signal indicative of the oxygen content in humid air. The sensor can then be actuated with a second, higher voltage applied to produce a second output signal indicative of the oxygen content in the humid air, when all the moisture in the air has dissociated at the oxygen sensor. Applying an intermediate voltage, average in magnitude between the first, lower voltage, and the second, higher voltage, can produce an oxygen sensor output signal indicating the oxygen content in dry air when the partial dissociation of moisture has occurred. After that, the oxygen content in dry air can be estimated from the ratio of the first and second output signals. The transfer function of the alcohol content can be adjusted by the estimated oxygen content in dry air, after which the first output signal can be adjusted to derive the amount of alcohol injected in the engine fuel using the adjusted transfer function of the alcohol content. Thus, it is possible to reduce the variability of the readings of different oxygen sensors in order to achieve more accurate readings of the alcohol content in the fuel. In one example, by detecting the amount of alcohol in the fuel, you can adjust the parameters of the engine, such as setting the time of ignition and / or the amount of fuel injected. As a result, despite the varying amount of alcohol contained in the fuel, it is possible to ensure that engine performance, fuel efficiency and / or emissions to the atmosphere can be maintained at the same level or can even be improved.

FIG. 1 schematically shows one cylinder of a multi-cylinder engine 10, which may be part of the propulsion system of a car. The engine 10 can be controlled, at least in part, by a control system comprising a controller 12 and by a command from the operator 132 of the vehicle via the input device 130. In the present example, the input device 130 comprises an accelerator pedal and a pedal position sensor 134 for generating an AC signal proportional to the pedal position. The combustion chamber 30 (i.e., the cylinder) of the engine 10 may comprise chamber walls 32 and a piston 36 located inside. The piston 36 may be coupled to the crankshaft 40 to convert the reciprocating motion of the piston into rotational motion of the crankshaft. The crankshaft 40 through the intermediate transmission system can be connected with at least one driving wheel of the vehicle. In addition, to start the engine 10 into operation, a starter motor can be connected to the crankshaft 40 via a flywheel.

The combustion chamber 30 may receive intake air from the intake manifold 44 through the intake port 42, and may exhaust the exhaust gases through the exhaust channel 48. The intake manifold 44 and the exhaust channel 48 may selectively communicate with the combustion chamber 30 through the corresponding intake valve 52 and exhaust valve 54. In some embodiments, the combustion chamber 30 may comprise two or more intake valves and / or two or more exhaust valves.

In the present example, the control of the intake valve 52 and the exhaust valve 54 can be performed by the respective cam drive systems 51 and 53. Each of the cam systems 51 and 53 may contain one or more cams and may use one or more of the following systems: cam profile switching system (CWP), variable valve timing system (CG), valve timing change system (CSC) and / or a valve lift change system (RPC) that can be controlled by controller 12 to change valve performance. The position of the intake valve 52 and the exhaust valve 54 can be determined by position sensors 55, 57, respectively. In alternative embodiments, the implementation of the intake valve 52 and / or exhaust valve 54 can control the actuation of the electric valve actuator. For example, cylinder 30 in an alternate embodiment may include an intake valve controlled by actuating an electric valve actuator, and an exhaust valve controlled by actuating the cam using control and control systems and / or IFG.

In some embodiments, each cylinder of the engine 10 may be configured with one or more fuel injectors fed to it. As a non-limiting example, it is shown that cylinder 30 includes one fuel injector 66. Fuel injector 66 shown connected to cylinder 30 directly to supply it with fuel is proportional to the pulse duration of the fuel injection signal (HTT) received from the controller via an electronic actuator 68. Thus, the fuel injector 66 performs a known direct injection (also called PV) of the fuel into the combustion cylinder 30.

It should be understood, in an alternative implementation, the nozzle 66 may be an injection nozzle into the intake duct providing fuel injection into the intake duct upstream from the cylinder 30. It should also be understood that the cylinder 30 can receive fuel from multiple nozzles injection, a number of injection nozzles into the intake duct, or a combination of some of the nozzles of the above types.

The fuel tank in the fuel system 172 can contain fuels with different qualities, for example, with different composition. These differences may relate to different alcohol contents, different octane numbers, different evaporation heat, different fuel mixtures and / or combinations of the above, and the like. The engine can run on an alcohol-based fuel mixture, for example, E85 (containing approximately 85% ethanol and 15% gasoline) or M85 (containing approximately 85% methanol and 15% gasoline). Alternatively, the engine can operate with other ratios of gasoline and ethanol contained in the fuel tank, including 100% gasoline and 100% ethanol, and with varying ratios of these components of the fuel, depending on how much ethanol is in the fuel, which the operator of the vehicle will flood into the tank. Moreover, the fuel characteristics in the fuel tank can change frequently. In one example, on the first day, the driver can put E85 fuel into the tank, E50 brand the next day, and E50 brand the next day. As a result, the composition of the fuel in the fuel tank may change dynamically depending on the level and composition of the fuel remaining in the tank at the time of refueling.

The result of day-to-day differences in refueling a tank can be the often changing composition of the fuel in the fuel system 172, which affects the composition and / or quality of the fuel supplied by the nozzle 66. Different fuel compositions injected by the nozzle 66 can be considered in this context as different types of fuel. In one example, different fuel compositions can be quantitatively described by their research octane number (EYE), alcohol percentage, percentage ethanol, etc.

It should be understood that although in one implementation the engine can be operated when fuel is injected with a variable composition through a direct injection nozzle, in other embodiments the engine can be operated using two injectors and changing the relative amount of injection through each of the injectors. It should also be understood that during operation of the engine with supercharging from a pressurization device, such as a turbocharger or a supercharger, the boost limit can be increased with an increase in the alcohol content in the fuel of variable composition.

As shown in FIG. 1, inlet channel 42 may include a throttle 62 containing throttle valve 64. In this particular example, the controller 12 may change the position of the throttle valve 64 via a signal applied to an electric motor or actuator included in throttle 62, in accordance with the configuration which is called electronic throttle control (EDS). Thus, the throttle 62 can be actuated to change the flow of intake air supplied to the combustion chamber 30 — one of the engine cylinders. Information about the position of the throttle valve 64 can be transmitted to the controller 12 via a throttle position signal (PD). Inlet channel 42 may include a mass air flow sensor (MRV) 120 and a manifold air pressure sensor 122 (DVK) for transmitting 12 corresponding MRV and DVK signals to the controller.

In the selected operating modes, in response to an ignition advance signal (03) from controller 12, the ignition system 88 may feed an ignition spark into the combustion chamber 30. Although spark ignition components are shown, in some embodiments, combustion chamber 30 or one or more other combustion chambers of engine 10 may operate in compression ignition mode, with or without an ignition spark.

It is shown that upstream of the exhaust emission reducing device 70, an exhaust gas sensor 126 is connected to the exhaust passage 48. Sensor 126 may be any suitable sensor for measuring the air-fuel ratio in the exhaust, for example, a linear oxygen sensor, or a universal or wide-range exhaust gas oxygen content (SCR) sensor, a dual-state oxygen sensor (COG), a heated content sensor oxygen in the exhaust gases (NKOG), sensor oxides of nitrogen, hydrocarbon or carbon monoxide. It has been shown that in the exhaust channel 48, downstream of the exhaust gas sensor 126, an exhaust emission reduction device 70 is located. Property 70 may be a three-way catalytic converter (TAC), nitrogen oxide trap, other various exhaust emission reduction devices, or a combination of these devices. In some embodiments, when the engine 10 is running, it can periodically discharge the emission-reducing device 70 by establishing a certain air-fuel ratio in at least one engine cylinder.

As shown in FIG. In example 1, the system also includes an intake air sensor 127 associated with the intake port 44. The sensor 127 may be any suitable sensor for measuring the air-fuel ratio in the exhaust gases, for example, a linear oxygen sensor, or a universal or wide-range sensor for oxygen in the exhaust (SHKG), a two-state oxygen sensor (COX), a heated exhaust oxygen sensor (NCSP), a sensor for nitrogen oxides, hydrocarbons or carbon monoxide.

In addition, in the considered embodiments, the exhaust gas recirculation (EGR) system can direct the desired portion of the exhaust gases from the exhaust port 48 to the intake port 44 through the EGR channel 140. The controller 12 by means of the EGR valve 142 can change the quantity of EGR gases supplied to the intake port 44. Furthermore, an EGR sensor 144 can be installed in the EGR channel 140, which can provide an indication of one or more of the following values: pressure, temperature and exhaust gas concentration . In some conditions, the EGR system can be used to control the temperature of the air-fuel mixture in the combustion chamber, thus providing a way to control the distribution of ignition in certain combustion modes. In addition, in some conditions, part of the combustion gases can be retained or trapped in the combustion chamber by controlling the opening and closing of the exhaust valve, for example, by controlling the valve timing change mechanism.

The controller 12 in FIG. 1 is shown as a microcomputer comprising: microprocessor device 102 (MPU), input / output ports 104 (IN / OUT), electronic storage medium of executable programs and calibration values, in this particular example depicted as a permanent memory chip 106 , random access memory 108 (RAM), non-volatile memory 110 (EZU) and data bus. In addition to the signals mentioned above, the controller 12 may receive various signals from sensors associated with the engine 10, and these signals may include: an MRI signal from the air mass flow sensor 120; engine coolant temperature signal (TCD) from sensor 112 associated with cooling jacket 114; ignition profile signal (PZ) from sensor 118 on the Hall effect (or other type of sensor) associated with the crankshaft 40, PD signal from the throttle position sensor; A DVK signal from sensor 122. An engine speed signal (CVP) can be generated by controller 12 from a PZ signal.

The electronic storage medium, made in the form of a ROM 106, can be programmed by machine-readable data, representing instructions executed by the microprocessor device 102 for implementing the methods described below, as well as other options that are assumed but not specifically listed.

As mentioned above, in FIG. 1 shows only one cylinder of a multi-cylinder engine, and each cylinder may likewise include its own set of intake / exhaust valves, a fuel injector, a spark plug, and the like.

FIG. 2 schematically depicts an example implementation of an oxygen sensor 200, for example, configured to measure oxygen concentration (O ₂ ) in the intake air stream in the intake channel or in the exhaust gas stream in the exhaust channel. For example, sensor 200 may function as a SCHUG sensor 126, described above with reference to FIG. 1. Sensor 200 contains multiple layers of one or more ceramic materials stacked on top of each other. In the embodiment of FIG. 2, five ceramic layers are designated as layers 201, 202, 203, 204, and 205. Among these layers is one or more layers of solid electrolyte capable of conducting oxygen in ionic form. As some examples of suitable solid electrolytes can be called materials based on zirconium oxide. In addition, in some embodiments, the implementation may be a heater 207, located in thermal contact with the layers to increase the ionic conductivity of the layers. Although the oxygen sensor shown is formed of five ceramic layers, it should be understood that the oxygen sensor may include another suitable amount of ceramic layers.

Layer 202 includes material or materials that create diffusion path 210. Diffusion path 210 is designed to introduce exhaust gases into the first internal cavity 222 by diffusion. The diffusion path 210 can be calculated with the possibility that one or more components of the intake air or exhaust gases, including the analyte (eg, O ₂ ), diffuse into the internal cavity 222 at a more restrictive rate than that with which the substance can be pumped or pumped out by a pair of pump electrodes 212 and 214. In this case, the stoichiometric level of O ₂ can be reached in the first internal cavity 222.

The sensor 200 also includes a second internal cavity 224 inside the layer 204, separated from the first internal cavity 222 by layer 203. The second internal cavity 224 is configured to maintain a constant partial pressure of oxygen corresponding to the stoichiometric condition, for example, the level of oxygen present in the second internal cavity 224, is equal to that which the exhaust gas would have if the air-fuel ratio were stoichiometric. The oxygen concentration in the second internal cavity 224 is maintained at a constant pump voltage V _cp . In this example, the second internal cavity 224 may be referred to as a reference cell.

A pair of measuring electrodes 216 and 218 is arranged to communicate with the first internal cavity 222 and with the reference cell 224. The pair of measuring electrodes 216 and 218 register a concentration gradient that can develop between the first internal cavity 222 and the reference cell 224 due to the fact that the oxygen concentration in the intake air or in the exhaust gases will be higher or lower than the stoichiometric level. A high oxygen concentration may be the result of a lean air intake or an exhaust gas mixture, and a low oxygen concentration may be due to the enrichment of the mixture.

The pair of pump electrodes 212 and 214 is arranged to communicate with the internal cavity 222 and is configured to electrochemically pump out a selected gas component (for example, O ₂ ) from the internal cavity 222 through layer 201 to the outside of sensor 200. Alternatively, a pair of pump electrodes 212 and 214 be made with the possibility of electrochemically pumping the selected gas through layer 210 into the internal cavity 222. In this example, a pair of pump electrodes 212 and 214 can be called an oxygen pump cell.

The electrodes 212, 214, 216 and 218 can be made of a variety of suitable materials. In some embodiments, the implementation of the electrodes 212, 214, 216 and 218 at least partially can be made of a material that is a catalyst for the dissociation of molecular oxygen. Examples of such materials, among others, are electrodes containing platinum and / or silver.

The process of electrochemical pumping of oxygen from the internal cavity 222 or into it involves applying a voltage V _p to a pair of electrodes 212 and 214. The voltage V _p pumping applied to the oxygen pumping cell pumps oxygen into or out of the first internal cavity 222 to maintain stoichiometric oxygen in the cell pumping cavity. The resulting pump current I _p is proportional to the oxygen concentration in the exhaust gas. The control system (not shown in Fig. 2) generates a pump current signal I _p depending on the pump voltage V _p required to maintain the stoichiometric level inside the first internal cavity 222. That is, leaning the mixture will lead to the pumping of oxygen from the internal cavity 222, and enrichment of the mixture will lead to the injection of oxygen into the internal cavity 222.

It should be understood that the oxygen sensor described herein is just one example implementation of an oxygen sensor, and that other embodiments of oxygen sensors may have additional and / or alternative features or designs.

As specified further in the text shown in FIG. 2, an oxygen sensor may preferably be used to estimate the exact amount of alcohol in the fuel burned in the engine, regardless of the variability of the oxygen sensor readings in the intake air or exhaust gases. In particular, it is possible to determine the correction of the transfer function of the alcohol content by determining the estimated oxygen content in dry air based on the ratio of the output signal of the oxygen sensor at the first, lower voltage to the output signal of the oxygen sensor at the second, higher voltage. Then, to estimate the ethanol content in the fuel, the corrected transfer function can be applied to the readings of the oxygen content in humid air at the first, lower voltage.

FIG. 3 is a block diagram illustrating an algorithm 300 for accurately estimating the amount of alcohol contained in a fuel while adjusting the transfer function of the alcohol content to the variability of the oxygen sensor readings, such as described above with reference to FIG. 2 sensor 200 oxygen. In particular, the algorithm 300 determines the amount of alcohol contained in the fuel injected into the engine, thereby determining the type of fuel based on the voltage values applied to the sensor pump cell as long as there are selected conditions for supplying the engine with fuel and adjusting the transfer function of the alcohol content.

At step 310 of algorithm 300, engine operating conditions are determined. The engine operating conditions may include, for example, an air-fuel ratio, the volume of the EGR flow entering the combustion chambers, and the conditions for supplying the engine with fuel.

After the engine operating conditions are determined, the algorithm 300 proceeds to step 312, in which it is determined whether the selected conditions are satisfied. For example, when the oxygen sensor is an intake air oxygen sensor located in the intake duct, the selected conditions may include the EGR state being activated and no purge or crankcase ventilation gas supply to the intake manifold. In another example, when the oxygen sensor is an exhaust gas oxygen sensor located in the exhaust channel, the conditions selected may include conditions without supplying the engine with fuel. Conditions without fuel supply to the engine include conditions for the vehicle to slow down and engine operating conditions under which the fuel supply is interrupted, but the engine continues to rotate and at least one intake and one exhaust valves continue to operate; that is, air flows through one or more cylinders, but fuel is not injected into the cylinders. In conditions where the engine is not supplied with fuel, it is not burned and ambient air can pass through the cylinder from intake to exhaust. Thus, a sensor, such as a sensor for oxygen in the intake air or a sensor for oxygen in the exhaust gases, can receive ambient air on which measurements can be made, for example, recording humidity of ambient air.

As mentioned, conditions without fuel supply to the engine may include, for example, shutting off the fuel supply during deceleration (SCR). The USPP is a reaction to the pedal’s actions of the operator (for example, in response to a driver’s release of gas and when the car accelerates by more than a threshold value). The USPP conditions can be repeated during one driving cycle, therefore, during the driving cycle, numerous indicators of ambient air humidity can be generated, for example, under each USPTZ condition. Consequently, according to the amount of water contained in the exhaust gases, it is possible to accurately identify the type of fuel, despite the fluctuations in humidity between driving cycles or even during one driving cycle.

As shown in FIG. 3, if it is determined that the selected operating conditions are not satisfied, the algorithm 300 proceeds to step 313 to continue the current operation of the oxygen sensor (at the current pump voltage) to determine the amount of alcohol contained in the fuel according to the previously determined correction factor. Conversely, if it is determined that the selected operating conditions are satisfied, then the algorithm 300 proceeds to step 314, where the first pump voltage (V ₁ ) is pumped to the oxygen pump cell of the oxygen content sensor in the exhaust gases and the first pump current (V _P1 ) is obtained. The first pump voltage may be such that oxygen will be pumped out of the cell, but low enough (for example, V ₁ = 450 mV) in order to not dissociate oxygen compounds, such as H ₂ O (water). For example, at the first pumping voltage, the oxygen sensor may not cause dissociation of water molecules at all. The first voltage supplied produces a sensor output signal in the form of a first pump current (I _P1 ) indicating the amount of oxygen in the test gas. In this example, since the engine is under selected conditions (for example, in conditions without fuel supply to the engine), the amount of oxygen can correspond to the amount of oxygen in the fresh air surrounding the vehicle, or an indication of the oxygen content in humid air.

After the amount of oxygen is determined, the algorithm 300 proceeds to step 316, where a second pump voltage (V ₂ ) is applied to the sensor oxygen pump cell and a second pump current (I _P2 ) is obtained. The second voltage may be greater than the first voltage applied to the sensor. In particular, the magnitude of the second voltage may be sufficient for the target oxygen compound to dissociate. For example, the second voltage can be quite high (for example, V ₂ = 1.1 V) for the dissociation of all H ₂ O molecules into hydrogen and oxygen. Submitted by the second voltage produces a second current (I _P2 ) pumping, indicating the amount of oxygen and water in the test gas. It should be understood that the term “water” as used herein in the context of “amount of oxygen and water” refers to the amount of oxygen from dissociated H ₂ O molecules in the test gas.

In one particular example, the second voltage can be 1080 mV, and at this value the water in the air completely dissociates (for example, at a voltage of 1080 mV, 100% of the water contained in the air dissociates). This second voltage may be greater than the third, medium voltage, in which the water contained in the air dissociates partially (for example, dissociates 40% of the water contained in the air). In one example, the third, average voltage may be about 920 mV. In another example, the third, average voltage may be about 950 mV. The one shown in FIG. 4, plot 400 shows the oxygen sensor output for a range (for example, from 1.5% to 4% humidity) of humidity conditions. As shown, the sensor output at 920 mV corresponds to the reading for dry air in this range of humidity conditions. The output signal of the sensor at 1.1 V corresponds to the reading for humid air, when all the water contained in the air dissociates on the sensor, and the output signal of the sensor at 4.5 V corresponds to the reading for moist air when the air contained in the air does not dissociate. That is, the readings of the oxygen content in dry air can be obtained from the ratio of the output signals of the oxygen sensor, when the oxygen sensor is activated at 4.5 V and 1.1 V. In an alternative implementation, the readings of the oxygen content in dry air can be obtained from the relationship output of the oxygen sensor when the sensor is activated at a voltage below 0.92 V, when water does not dissociate (for example, even partially does not dissociate) and at a voltage above 0.92 V, when water completely dissociates (for example, dissociate 100% water).

At step 318, the reading of the oxygen content in dry air and the associated correction factor are determined from the first pump current and the second pump current. For example, as described above, by activating the sensor at 450 mV (or at a similar voltage at which no water association occurs on the sensor), a lower pump current and oxygen reading can be obtained, and by actuating the sensor at 1080 mV (or at a similar voltage at which all water dissociates at the sensor), a higher pump current and an indication of the oxygen content can be obtained. Then, from the ratio of lower pumping current and higher pumping current, it is possible to estimate the pump current for dry air, indicating the oxygen content of the dry air. For example, a sum of 40% higher pump current and 60% lower pump current can be substantially equal to the pump current and the oxygen content for dry air. In an alternative example, other percentages of higher and lower pump currents can be added to determine the pump current for dry air. For example, if higher or lower voltages differ from 450 mV and 1080 mV, respectively, then the corresponding percentages used to determine the ratio between higher and lower pump currents may vary proportionally.

Estimated from the relationship between higher and lower pump currents (for example, between higher and lower oxygen sensor output signals corresponding to higher and lower voltages), the oxygen content in dry air can then be used to determine the correction factor or to correct alcohol transfer function. As described above, the correction factor is a coefficient that compensates for the variability of the sensor readings. In one example, the correction factor can be determined based on the ratio of the output signal of the reference sensor to the estimated reading of the oxygen content in dry air at the ratio between the first and second voltages. In other words, the correction factor can be determined based on the ratio of the output signal of the reference sensor to the ratio of the first and second sensor signals obtained by applying the first and second voltages, respectively. After the correction factor is determined, at step 320, the transfer function of the alcohol content is updated based on the correction factor found.

After the first and second pump currents have been developed, at step 322 shown in FIG. 3 algorithms 300 it is possible to determine the amount of water contained in the test gas. For example, when the second pump current is high enough to dissociate substantially all of the water molecules in the test gas, then in order to determine the value corresponding to the amount of water, the value of the first pump current can be subtracted from the value of the second pump current.

Finally, at step 324, it is possible to determine the amount of alcohol contained in the fuel, thereby determining the type of fuel. For example, the adjusted transfer function can be applied to the first pump current to obtain accurate information about the amount of alcohol (for example, the percentage of ethanol) in the fuel injected into the engine. In some implementations, the machine-readable storage medium of the control system receiving data from the sensor may contain instructions for identifying the amount of alcohol.

Thus, according to the output signals (for example, pump currents) of the sensor, generated in response to energization of the oxygen pump cell of the oxygen content of the intake air oxygen sensor or of the oxygen content of the exhaust gases under conditions of fuel supply to the engine, as well as the correction coefficient of the transfer function, you can identify the exact indicator of the amount of alcohol contained in the fuel (for example, the percentage of ethanol). In addition, after the type of fuel has been determined, it is possible to adjust various engine operating parameters to preserve the engine's efficiency in terms of fuel and / or emissions to atmosphere, which will be described in detail later in the text.

The method also, after step 318, may include determining the corrected output signal of the oxygen sensor from a correction factor and the measured oxygen (eg, from the first output signal). The adjusted output of the oxygen sensor may be a measurement of the oxygen sensor, adjusted for the variability of the readings of various oxygen sensors and / or for changes over time of the oxygen sensor. Then the corrected oxygen sensor reading can be used in additional engine control functions or calculations, for example, for estimating the EGR flow, if the oxygen sensor is an oxygen intake sensor located in the engine intake system.

FIG. 5 shows a graph illustrating the difference in the percentage of ethanol and due to the variability of the readings of different sensors. For example, curve 502 shows the first transfer function for a normal sensor. Curve 504 shows the second transfer function of the sensor, which indicates a lower ethanol content than in the case of a normal sensor. Curve 506 shows the third transfer function of the sensor, indicating a higher ethanol content than in the case of a normal sensor. As can be seen from this illustration, due to the discrepancy between the readings of different sensors, they may show different values of the percentage of ethanol in the same environment. If so, the transfer function of the ethanol content can be adjusted using the first and second output signals of the oxygen sensor as described above, which will reduce the influence of the variability of the readings of different sensors and obtain a more accurate reading of the amount of alcohol contained in the fuel.

FIG. 6 shows a block diagram of a general control algorithm 600 for controlling engine performance parameters based on the amount of alcohol (for example, based on the corrected amount of alcohol found according to the above description of the adjusted transfer function) contained in the fuel injected into the engine. In particular, in accordance with the change in the amount of alcohol in the fuel, one or several parameters of the engine operation can be adjusted. For example, fuels containing different amounts of alcohol may have different properties, for example, viscosity, octane number, latent vaporization enthalpy, etc. This means that if you do not adjust the corresponding one or more operating parameters, then the engine’s performance, fuel economy and / or air emission may deteriorate.

At step 610 of algorithm 600, engine operating conditions are determined. Engine operating conditions may include, for example, an air-fuel ratio, installation of the timing of fuel injection and ignition timing. For example, the stoichiometric air-fuel ratio may be different for different types of fuel (for example, 14.7 for gasoline, 9.76 for E95), and the installation of fuel injection and ignition timing must be adjusted depending on the type of fuel.

After the operating conditions are determined, at step 612 of algorithm 600, an updated amount of alcohol is found in the fuel mixture and the humidity of the surrounding air. As described above, the output of the exhaust gas sensor or intake air can determine the type of fuel. After the type of fuel has become known, the algorithm 600 proceeds to step 614, where, under selected engine operating conditions, for example, during cold start or transitional conditions for supplying the engine with fuel, the amount of alcohol contained in the fuel is controlled by one or more desired operating parameters. engine For example, based on the estimated amount of alcohol contained in the fuel, the system may adjust the air-fuel ratio required for fuel combustion (for example, the stoichiometric air-fuel ratio). In addition, by the amount of alcohol contained in the fuel, the gains in the air-fuel ratio control channel with feedback can be tuned. In addition, the amount of alcohol contained in the fuel can be adjusted by the air-fuel ratio required when the engine is cold start. In addition to the above, the ignition timing (for example, ignition lag) and / or boost levels can be adjusted by the amount of alcohol contained in the fuel.

In some embodiments, for example, it is possible to adjust the timing of fuel injection and / or the amount of fuel injected. For example, if it is determined that under cold start conditions, the amount of alcohol in the fuel has increased (for example, from 10% ethanol to 30% ethanol), then it can increase the amount of fuel injected into the engine.

Another example would be the timing of the ignition of the detected amount of alcohol in the fuel. For example, if the detected percentage of alcohol is lower than that previously detected (for example, a change from 85% ethanol to 50% ethanol occurred), then the ignition time can be adjusted in the direction of delay in order to achieve higher engine output or boost without detonation.

If there are selected operating conditions, the various parameters of engine operation can be adjusted by the detected amount of alcohol contained in the fuel injected into the engine. Thus, it is possible to maintain or even improve the efficiency. engine and / or engine emissions, as well as its fuel economy.

As one embodiment, the method includes, under conditions without supplying the engine with fuel, supplying the sensor with the oxygen content in the exhaust gases of a first, lower voltage, at which no dissociation of water molecules occurs, and a second, higher voltage, at which molecules the waters completely dissociate. The method also includes finding a correction factor for the sensor based on the ratio of the first and second output signals generated when the first and second voltages are applied, respectively, and estimating the ethanol content of the fuel burned in the engine by applying the found correction factor to the transfer function obtained from the first output signal. Conditions without fuel supply to the engine include a fuel shutdown during deceleration event, and the method also includes adjusting the engine operation parameter based on the estimated ethanol content in the fuel, and this parameter includes an air-fuel ratio for burning fuel. The first output signal includes the first pump current generated in response to the supply of the first, lower voltage, and the second output signal includes the second pump current generated by applying the second, higher voltage, the first and second output signals indicating the amount of oxygen in humid air, and in this case the first, lower voltage is below the average voltage, the second, higher voltage is above the average voltage, and the average voltage is the voltage at which water molecules in the air partially dissociate, and the average voltage produces a third pumping current, indicating the amount of oxygen in dry air. In one example, the average voltage may be 920 mV, the first, lower voltage, may be 450 mV, and the second, higher voltage, may be 1080 mV. In addition, the sensor oxygen content in the exhaust gas is placed upstream from the inlet of the EGR channel, made with the possibility of recirculation of the exhaust gas from the exhaust manifold to the intake manifold of the engine.

As another embodiment, the method includes, when the engine is not supplied with gases blowing and crater ventilation, supplying the sensor with the oxygen content in the intake air of the first, lower voltage, at which no dissociation of water molecules, and the second, higher voltage occur in which water molecules completely dissociate. The method also includes finding a correction factor for the sensor based on the ratio of the first and second output signals generated when the first and second voltages are applied, respectively, and estimating the ethanol content of the fuel burned in the engine by applying the found correction factor to the transfer function obtained from the first output signal. The first output signal includes the first pump current generated in response to the supply of the first, lower voltage, the first pump current indicating the amount of oxygen in humid air, and the second output signal includes the second pump current generated by applying the second, higher voltage, the second output signal indicates an increase in the amount of oxygen as a result of the dissociation of moisture, and the ratio between the first and second output signals indicates the amount of oxygen in dry air. A sensor for oxygen in the intake air is located upstream of the intake throttle and downstream of the EGR channel outlet, configured to recirculate the exhaust gas from the exhaust manifold to the engine intake manifold. The method also includes estimating the EGR flow in the EGR channel using the adjusted intake air oxygen sensor output signal based on the oxygen intake air oxygen sensor output signal and the correction factor found.

Note that the examples of control and evaluation algorithms included in this application can be used with a variety of engine and / or vehicle system configurations. The control methods and algorithms disclosed in this application may be stored as executable instructions in a non-volatile memory. The specific algorithms disclosed in this application may be one or any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threaded, etc. Which implies that the various actions, operations and / or functions illustrated can be performed in a specified sequence, in parallel, and in some cases - can be omitted. Similarly, the specified processing order is not necessarily required to achieve the distinctive features and advantages of the embodiments of the invention described herein, but serves for convenience of illustration and description. One or more of the illustrated actions, operations, and / or functions may be re-executed depending on the particular strategy employed. In addition, the disclosed operation steps and / or functions may graphically depict code programmed in a non-volatile memory of a computer readable computer storage medium in an engine management system.

It should be understood that the configurations and algorithms disclosed in the present description are merely examples, and that specific embodiments do not have a restrictive function, since various modifications are possible. For example, the above technology can be applied to engines with V-6, I-4, I-6, V-12 cylinders, in a scheme with 4 opposite cylinders and in other types of engines. The subject matter of the present invention includes all new and non-obvious combinations and derivatives of combinations of various systems and circuits, as well as other distinctive features, functions and / or properties disclosed in the present description.

In the following claims, in particular, attention is focused on certain combinations of components and derived combinations of components that are considered new and not obvious. In such claims, reference may be to an element of either the “first” element or an equivalent term. It should be understood that such clauses include one or more of these elements, without requiring, and not excluding, two or more of these elements. Other combinations and derivative combinations of the disclosed distinctive features, functions, elements or properties may be included in the formula by correcting the existing clauses or by presenting new claims in the present or related application. Such claims, regardless of whether they are broader, narrower, equivalent or different in terms of the scope of the idea of the original claims, are also considered to be included in the present invention.

Claims (28)

1. The method of engine control, including: under selected conditions, actuation of the oxygen sensor at a lower reference voltage, at which water molecules do not dissociate, to generate a first output signal and at a higher reference voltage, at which water molecules dissociate completely, to generate a second output signal; and finding the correction factor for the sensor on the first and second output signals. 2. The method according to claim 1, further comprising adjusting the parameter according to the alcohol content in the fuel burned in the engine, estimated both by the first output signal and the correction factor found. 3. The method according to p. 2, in which the parameter represents the required air-fuel ratio for combustion in the engine. 4. A method according to claim 1, wherein the first output signal includes the first pump current generated in response to actuation at a lower reference voltage, and the second output signal includes the second pump current generated in response to the induction in action at a higher reference voltage. 5. A method according to claim 1, wherein the first output signal indicates the oxygen content for the humid air, and the second output signal indicates an increase in the oxygen content as a result of the dissociation of the humid air, and the pump current for dry air is based on the ratio of the first and second output signals and the current Pumping for dry air indicates the oxygen content for dry air. 6. A method according to claim 1, wherein the correction factor is a correction factor for dry air, compensating for the variability of the sensor readings, while finding the correction factor for the first and second output signals includes finding the correction factor based on the ratio of the output signal of the reference sensor to the ratio between the first and second output signals. 7. A method according to claim 6, in which the reference transfer function of the alcohol content of the sensor is based on the output signal of the reference sensor. 8. A method according to claim 7, in which the evaluation of the alcohol content in the fuel, both on the first output signal and on the found correction factor includes: regulation of the reference transfer function of the alcohol content of the sensor according to the found correction factor; and applying the adjusted alcohol transfer function to the first sensor output. 9. A method according to claim 1, wherein the oxygen sensor is a universal sensor of oxygen in the exhaust gases associated with the exhaust manifold of the engine upstream of the catalytic converter exhaust gases. 10. A method according to claim 9, in which the selected conditions include conditions without supplying the engine with fuel and conditions without supplying the engine with fuel include the event of switching off the fuel supply during deceleration. 11. A method according to claim 1, wherein the oxygen sensor is an intake air oxygen sensor coupled to an engine intake manifold upstream of the intake compressor. 12. A method according to claim 11, in which the selected conditions include the inclusion in the work of exhaust gas recirculation (EGR) and the lack of reception in the intake manifold purge gases or crankcase ventilation gases. 13. The method of engine control, which includes: in conditions without the supply of the engine with fuel the supply to the sensor of the oxygen content in the exhaust gases as the first, lower voltage, in which the water molecules do not dissociate, and the second, higher voltage, in which the water molecules completely dissociate; finding a correction factor for the sensor based on the ratio of the first and second output signals generated when the first and second voltages are applied, respectively, and estimating the content of ethanol in the fuel burned in the engine by applying the found correction factor to the transfer function based on the first output signal. 14. The method according to claim 13, wherein the conditions without supplying the engine with fuel include the event of shutting off the fuel supply during deceleration, and the method also includes adjusting the engine operation parameter based on the estimated ethanol content in the fuel and wherein the parameter includes air fuel ratio for burning. 15. The method according to claim 13, wherein the first output signal includes a first pump current generated in response to the supply of a first, lower voltage, and the second output signal includes a second pump current generated in response to the supply of a second, higher voltage, the first and second output signals indicate the amount of oxygen in humid air and the first, lower, voltage is below average voltage, and the second, higher voltage is above average voltage, the third voltage produces the third pump, indicating the amount of oxygen in dry air. 16. A method according to claim 13, in which the sensor oxygen content in the exhaust gas is placed upstream from the catalytic converter exhaust gases and upstream from the inlet of the EGR channel, made with the possibility of recirculation of exhaust gas from the exhaust manifold to the intake manifold of the engine. 17. The method of engine control, including: when the gases of the purge and crankcase ventilation are not supplied to the engine, the supply to the sensor of the oxygen content in the intake air of the first, lower voltage at which water molecules do not dissociate, and the second, higher voltage at which water molecules dissociate completely; finding a correction factor for the sensor based on the ratio of the first and second output signals generated when the first and second voltages are applied, respectively, and estimating the content of ethanol in the fuel burned in the engine by applying the found correction factor to the transfer function based on the first output signal. 18. The method according to p. 17, in which the first output signal includes the first pump current generated in response to the supply of the first, lower, voltage, the first output signal indicates the amount of oxygen in moist air, and the second output signal includes the second the pump current generated in response to the supply of a second, higher voltage, the second output signal indicates an increase in the oxygen content as a result of the dissociation of moisture, and the ratio between the first and second output signals indicates the oxygen content ode in dry air. 19. A method according to claim 17, in which the sensor oxygen content in the intake air is located upstream from the intake throttle and downstream from the output of the channel EGR, made with the possibility of recirculation of exhaust gas from the exhaust manifold to the intake manifold of the engine. 20. The method of claim 19, also including estimating the EGR flow to the EGR channel using the adjusted output signal of the oxygen content in the intake air, based on the output signal of the oxygen content in the intake air and the correction factor found.

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