Method and device for operating an internal combustion engine with a predefined air-fuel mixture
By introducing additional correction parameters and Gaussian functions into the internal combustion engine, the problem of nonlinear error in the air-fuel ratio was solved, enabling precise adjustment of the air-fuel ratio and improving engine performance and emission purification.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ROBERT BOSCH GMBH
- Filing Date
- 2022-02-11
- Publication Date
- 2026-06-02
AI Technical Summary
Existing technologies struggle to effectively compensate for nonlinear errors in the air-fuel ratio in internal combustion engines, leading to inaccurate mixture regulation and impacting engine performance and emissions.
By introducing other correction parameters into the air-fuel ratio adjustment, nonlinear errors are compensated for in each operating range according to the internal combustion engine's operating range and actual filler volume. Correction is performed using correction offset and factor, combined with Gaussian function and time filtering technology, to achieve precise adjustment of the air-fuel ratio.
It improves the precision of air-fuel ratio adjustment, reduces adaptation time, and enhances engine stability and emission purification capabilities.
Smart Images
Figure CN114922738B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to internal combustion engines, and more particularly to methods for regulating and adapting the air / fuel mixture supplied to the cylinders of an internal combustion engine. The invention particularly relates to methods for regulating and adapting the air / fuel mixture during the operation of an internal combustion engine. Background Technology
[0002] In normal operation, gasoline engines run using an air / fuel mixture that is close to stoichiometric equilibrium, meaning the λ value of the air / fuel mixture is approximately 1. Such internal combustion engines are now almost exclusively represented by what are known as EGAS systems. EGAS systems incorporate electronic control of a throttle body with a throttle valve and λ adjustment for regulating and adapting the air / fuel ratio. This adjustment or adaptation can be achieved using sensors to detect the air present in the combustion chamber (e.g., an air mass meter), or by using an intake manifold pressure sensor and sensors to detect exhaust gas composition (e.g., a λ sensor).
[0003] In conventional gasoline engine operation, air is delivered to the engine cylinders under the control of the throttle valve, and a stoichiometric amount of fuel corresponding to this air volume is injected into the combustion chamber or into the intake manifold located upstream of the intake valve. Mixture regulation attempts to at least approximately set the air / fuel mixture to stoichiometric equilibrium. The setting of the air delivered to the cylinders (the so-called air fill factor) is predetermined by the driver of the motor vehicle running the internal combustion engine. The driver controls torque, particularly via an accelerator pedal electronically connected to control equipment, where the accelerator pedal position is generally interpreted as corresponding to the driver's desired torque and thus translating into a corresponding expected fill factor. The expected fill factor corresponds to the amount of air required in the cylinders that generate torque to provide the driver's desired torque. The expected fill factor corresponds to the throttle valve position, causing the control equipment to adjust the throttle valve accordingly.
[0004] Besides the dynamic effects, the actual filler volume follows the adjusted expected filler volume, which is continuously detected by the control device via a model or sensor. The amount of fuel corresponding to the actual filler volume is calculated and delivered to the cylinder. Because deviations occur between the actual filler volume or the amount of fuel actually injected and the desired air filler volume or the desired amount of fuel to be injected due to aging effects, component tolerances, and such factors, an adjustment and adaptation method is implemented in the control device. In the case of filler volume adaptation, within the filler volume control used to calculate the expected position of the throttle, the air filler volume is corrected based on the expected filler volume pre-given by the driver's desired torque by comparing the expected filler volume with the measured actual filler volume. If the expected filler volume and the actual filler volume deviate from each other, it is assumed that the throttle model used does not accurately depict reality, and the model is adapted using a correction factor over a long period of time until the expected filler volume and the actual filler volume are consistent again. Thus, for example, contamination or drift effects of the throttle body during the vehicle's lifespan can be corrected and adapted.
[0005] Furthermore, mixture adaptation and adjustment are implemented to ensure a desired stoichiometric mixture with λ equal to or approximately 1, relative to component tolerances, contamination, or drift effects, enabling optimal exhaust emission purification via a downstream catalytic converter. To this end, the signal provided by the λ sensor is continuously monitored, and the mixture is adjusted and adapted (depending on the engine system configuration) either by matching the amount of injected fuel or by matching the air-fill quantity through a calibrated throttle position, using corresponding correction values.
[0006] For the operation of an internal combustion engine, the mixture regulation is typically equipped with pre-control for adjusting the fuel-air ratio, or λ value. This pre-control uses a correction function to adjust the air-fill quantity determined by the measured λ value, which is typically geared towards the engine's operating point. This is to prevent mismatch in the pre-control.
[0007] For example, a mixture adaptation is known from US 4,584,982, in which different correction variables are provided for different operating ranges of the internal combustion engine. These correction variables are used to correct for different types of errors. For example, errors in determining air quality act multiplicatively on fuel metering, while the effects of injection valve start-up delay and leaking air act additively. These errors are corrected by the mixture adaptation. However, current adaptation methods are based solely on the correction of offset and multiplicative errors, making it particularly difficult to characterize nonlinear deviations or errors via conventional mixture adaptation. Summary of the Invention
[0008] Therefore, the object of the present invention is to provide a possibility for adapting the mixture error of an internal combustion engine in an improved manner.
[0009] This task is set up by the method for operating an internal combustion engine by means of a mixture adaptation according to claim 1, and by the corresponding equipment and engine system having an internal combustion engine according to the parallel claims.
[0010] Other construction options are described in the dependent claims.
[0011] According to the first aspect, a method is provided for operating an internal combustion engine (particularly in a gasoline engine) by means of adjusting the air-fuel ratio of the air-fuel mixture, the method comprising the following steps:
[0012] - Provides the actual λ value illustrating the current air-fuel ratio information, and provides the expected λ value illustrating the desired air-fuel ratio information;
[0013] - Adjustments are performed based on the actual and expected λ values to determine the total amount of fuel to be delivered.
[0014] - From the pre-control related to the measured or simulated actual fill volume, the expected injection volume is determined according to at least one correction parameter, in particular correction offsets and / or correction factors, wherein the measured or simulated actual fill volume or the fuel volume derived from the actual fill volume is loaded with at least one correction parameter in order to obtain the expected injection volume;
[0015] In addition, based on the operating range of the internal combustion engine, other correction parameters are provided. The measured or simulated actual fill volume or expected fuel volume is loaded with these other correction parameters in order to compensate for nonlinear errors when setting the air-fuel ratio.
[0016] It can be configured to determine the operating range based on the measured or simulated actual fill volume, so that other calibration parameters are related to the measured or simulated actual fill volume.
[0017] In this way, in addition to adapting the correction offset and / or correction factor according to conventional adaptation methods, other correction parameters can be considered on a per-run range or per-run point basis to compensate for nonlinearities. Thus, the moving adaptation enables a simple and robust way to compensate for tolerance-induced nonlinearities.
[0018] Therefore, the above method has the following advantages: it requires less adaptation time because, for the overall adaptation of the engine system, it is not necessary to individually experience all operating ranges to obtain the corresponding correction parameters. After adapting the correction parameters for the entire range specified by the correction offset and correction factor, the values of other correction parameters can be precisely adjusted for each operating range.
[0019] The values of other calibration parameters related to the operating range are determined based on the adaptation data set. The actual filler quantity or fuel metering can be applied using other calibration parameters by simply adding them, by multiplying them, or by linearizing the adaptation line between two adjacent operating ranges using the least squares method.
[0020] In addition, other relevant influencing variables that can be considered to determine the operating range may be taken into account, such as the activation of the catalyst heating method, the temperature of the cooling medium, or other operating conditions.
[0021] In addition, other correction parameters can be considered with the following weights: in particular, by applying a Gaussian function or a Hutfunktion function, the weights at the boundaries of the corresponding operating range are lower than the weights in the core region of the corresponding operating range.
[0022] It is possible to configure, in particular using the PT1 filter, to perform time filtering on other correction parameters, thereby making the correction smooth over time.
[0023] Furthermore, given a defined actual filling volume for the corresponding operating range, other calibration parameters can be adapted periodically or continuously based on the measured or simulated actual injection volume.
[0024] In particular, other correction parameters can be adapted based on the deviation between the average actual injection quantity and the average expected injection quantity within the operating range. Alternatively, other correction parameters can be adapted based on the deviation between the actual injection quantity and the corresponding expected injection quantity at the center of mass within the operating range.
[0025] Other correction parameters can be compared individually to pre-defined thresholds for the operating range, and if the value of another correction parameter in one of the operating ranges exceeds the pre-defined threshold by an amount, the error can be signaled.
[0026] According to other aspects, a device is provided for (particularly in gasoline engines) operating an internal combustion engine by means of adjusting the air-fuel ratio of the air-fuel mixture, wherein the device is configured to:
[0027] - Provides the actual λ value illustrating the current air-fuel ratio information, and provides the expected λ value illustrating the desired air-fuel ratio information;
[0028] - Adjustments are performed based on the actual and expected λ values to determine the total amount of fuel to be delivered.
[0029] - From the pre-control related to the measured or simulated actual fill amount, the expected injection amount is determined according to at least one correction parameter, in particular a correction offset and / or a correction factor, wherein the measured or simulated actual fill amount or the fuel amount derived from the actual fill amount is loaded with at least one correction parameter in order to obtain the expected injection amount;
[0030] In addition, based on the operating range of the internal combustion engine, other correction parameters are provided. The measured or simulated actual fill volume or expected fuel volume is loaded with these other correction parameters in order to compensate for nonlinear errors when setting the air-fuel ratio. Attached Figure Description
[0031] The preferred embodiments are then described in more detail with reference to the attached figures.
[0032] Figure 1 A schematic diagram of an engine system with an internal combustion engine featuring intake manifold injection is shown.
[0033] Figure 2 A block diagram illustrating the functions used to adapt the air-fuel ratio in an internal combustion engine within an engine system is shown; and
[0034] Figure 3 The diagram shows the adaptation characteristic curves for different operating ranges. Detailed Implementation
[0035] Figure 1 A schematic diagram of an engine system 1 having an internal combustion engine 2, particularly for use in motor vehicles, is shown. The internal combustion engine 2 is a gasoline engine, which in this embodiment has four cylinders 3. Air is supplied to the internal combustion engine 2 or the cylinders 3 via an air delivery system 4. In the air delivery system 4, an air quality sensor 5 is arranged on the input side. This air quality sensor 5 can be configured as a hot-film air quality sensor to detect the amount of air flowing into the internal combustion engine 2.
[0036] Downstream of the air quality sensor 5 is a throttle adjustment device with a throttle valve 6, which controls the airflow in the internal combustion engine 2 by setting the throttle valve 6, and thus controls the amount of air present in the cylinder 3. The amount of air is defined here as the amount of air available in the cylinder 3 during combustion, and is described as an air mass flow that is proportional to the engine speed.
[0037] An injection valve 7 is arranged between the throttle valve 6 and the intake valve (not shown) of the cylinder 3 to inject a predetermined amount of fuel into the so-called intake manifold section of the air delivery system 4. Alternatively or additionally, the injection valve 7 may be arranged directly on the cylinder 3 to enable direct fuel injection.
[0038] Combustion exhaust gas from cylinder 3 is discharged via exhaust gas discharge section 8. A λ sensor 9 is arranged in exhaust gas discharge section 8, which measures the oxygen content of the combustion exhaust gas and provides a corresponding λ signal. The λ signal enables determination of whether the air / fuel mixture supplied in cylinder 3 for combustion is in stoichiometric equilibrium, or to determine whether there is too much or too little fuel or too much or too little air during combustion.
[0039] If, at the moment of combustion, there is more air in the combustion chamber of cylinder 3 than required for the stoichiometric air / fuel ratio, a mixture that is too lean is involved. In the case of the stoichiometric air / fuel ratio, the λ value corresponding to value 1 is greater than 1. If, at the moment of combustion, there is more fuel in the combustion chamber of cylinder 3 than required for the stoichiometric air / fuel ratio, a mixture that is too rich is involved, which is described by a λ value less than 1.
[0040] Engine system 1 is operated by control unit 10. Control unit 10 detects system state variables via various sensors and manipulates corresponding actuators to operate internal combustion engine 2. In this way, control unit 10 obtains, for example, information about the amount of air flowing into cylinder 3 (that is, about the air filler) and information about the instantaneous actual λ value, which indicates whether the air / fuel mixture was too rich or too lean during combustion in cylinder 3, or whether it had a balanced stoichiometric air / fuel ratio of 1.
[0041] Based on the system state variables of engine system 1, and based on the driver's desired torque FWM (expected engine torque) pre-given externally, control device 10 then pre-given the operation for the throttle adjustment device and the operation for the injection valve 7. In order to operate the throttle adjustment device, a voltage corresponding to a determined adjustment angle of the throttle 6 is correspondingly pre-given.
[0042] The injection valve 7 is controlled by the opening duration, which is basically related to the amount of fuel to be injected.
[0043] Control unit 10 controls internal combustion engine 2 to provide the desired engine torque. This is based on measured or simulated system state variables, such as, for example, the manipulation of the injection valve 7 for injecting fuel based on a determined fuel metering and the amount of fresh air flowing into the internal combustion engine. However, these variables are subject to error.
[0044] To compensate for potential deviations between the air-fuel ratio and its actual value, a so-called mixture adaptation is performed. This involves correcting the calculated fuel quantity (fuel metering) or the measured or simulated air fill (derived from the fresh air mass flow) using one or more correction parameters. The correction parameters may include a pre-defined correction offset k. off and the pre-given correction factor k F The pre-given correction offset k off and the pre-given correction factor k F The actual filler quantity or fuel metering to be corrected is determined in relation to the pre-controlled actual filler quantity or fuel metering and is applied to the correction. For this purpose, the actual filler quantity or fuel metering to be corrected is, for example, additively loaded with a correction offset k. off And it is multiplicatively loaded with a correction factor k F .
[0045] Figure 2 The functions implemented in the control device 10 are shown in detail. In the control device 10, the function blocks are implemented either as software or as hardware.
[0046] Based on the driver's desired torque FWM or other expected torque preset by the driver through operation of the accelerator pedal, the engine system 1 is operated to adjust the throttle valve 6. In the case of a gasoline engine, the driver's desired torque FWM preset by the driver via the corresponding position of the accelerator pedal essentially corresponds to information about the expected fill volume, which is directly converted into the expected position of the throttle valve 6. This decisively determines the air mass flow entering the internal combustion engine 2.
[0047] By evaluating the amount of air LM flowing through the air delivery system 4, the fill quantity detection block 22 determines the actual fill quantity F. ist The air volume LM can be determined using air quality sensor 5. The provided information pertains to the actual fill volume F. ist The information is used as the basis for mixture conditioning. The entire mixture conditioning process includes pre-control in pre-control block 23 and mixture conditioning in mixture conditioning block 26, in which the information corresponding to the actual filling amount F is determined. ist The expected injection volume MV.
[0048] The air / fuel mixture is regulated using the mixture regulating block 26. This regulation allows for the setting of both proportional and derivative components. The air / fuel mixture regulation is based on the actual λ value Lambda supplied by the λ sensor 9. ist And used to calibrate the air / fuel ratio to the expected λ value Lambda. soll A pre-defined air / fuel ratio. For this purpose, the fuel quantity difference dMR is provided as an adjustment variable. The fuel quantity difference dMR takes into account the expected injection quantity MV determined by pre-control block 23. The expected injection quantity can be determined based on the measured λ deviation, that is, it is determined as a fuel quantity that may have resulted in the desired expected λ value (i.e., tolerance correction).
[0049] Information about the expected injection volume MV is first fed to the system that takes into account other correction parameters f. z The loading element 29 is then fed to the summing element 27, where the fuel quantity difference dMR is added to obtain the total fuel quantity MG.
[0050] The total fuel quantity MG is fed to the injection calculation block 24, which determines the opening duration of the injection valve 7 based on the total fuel quantity MG and controls the injection valve 7 accordingly.
[0051] To perform mixture adaptation, the measured actual filling amount F ist Loaded with correction parameter k off k F Correction parameter k off k F Provided via adapter block 25. Using an adaptation method known per se, implemented in adapter control block 21, the behavior of engine system 1 is monitored, and adjustments are made to the correction parameter k at a given time. off k F The determination and readjustment of the correction parameter k. off k F It is fed to pre-control block 23 and applied regardless of the operating range. Pre-control block 23 processes the corrected actual filling amount F. ist In order to provide the expected injection volume accordingly.
[0052] The determination of the correction parameters can be performed, for example, as described in published document DE 10 2011 006 5871. For this purpose, especially in the steady-state operation of an internal combustion engine, measurement data is determined based on the injected fuel quantity and the actual air-fuel ratio, and these measurement data are corrected using correction parameters based on a pre-given λ value (i.e., a pre-given air-fuel ratio). From the application of the least squares method to the measurement data, the correction offset k is obtained. off and correction factor kF .
[0053] In calibration block 28, other calibration parameters f are provided for each operating range. z The other correction parameters f z The solution is fed to loading element 29, where the expected injection quantity MV is loaded. In loading element 29, other correction parameters f are considered, in a suitable manner, particularly by additive or multiplicative loading of the expected injection quantity MV determined by pre-control. z .
[0054] In calibration block 28, calibration parameters f are provided, for example, in the form of a lookup table, for different operating ranges of engine system 1. z Through the actual filling amount F ist Alternatively, the information on the actual injection quantity determined thereby can predetermine the operating range, and this information can characterize the engine system's load and speed, as well as other state variables.
[0055] To avoid applying other correction parameters f z In cases where the engine system's operating point jumps from one operating range to the next, other correction parameters f can be considered with low weight at the boundaries of the operating range. z Furthermore, other correction parameters f can be fully considered within the core area of the corresponding operating range. z This can be achieved by loading other correction parameters with a Gaussian function or a hat function, or something similar, such that other correction parameters are considered to be 0 at the boundaries of the operating range, and other correction parameters f pre-given for that operating range are considered in the middle of the operating range. z The value of .
[0056] In addition, the correction block 28 can, for example, use a PT1 filter to perform time filtering on other correction parameters so that the correction intervention remains smooth over time despite transient, perhaps rapid, variations between operating ranges.
[0057] By determining the actual injection quantity M at the operating point ist The difference in injection volume between the expected injection volume MV and the actual instantaneous fill volume F determines additional correction parameters for the operating range. ist (The instantaneous actual filling amount F) ist The adaptation parameters, namely the correction offset and correction factor, are obtained when the operating point is associated with the running point.
[0058] exist Figure 3 The example illustrates the deviation between the actual injection quantity determined by an example and the expected injection quantity determined by the pre-control block.
[0059] Figure 3 The curve is plotted using the actual fill amount F. ist This shows the actual injection volume, where the corrected offset k off and correction factor k F The straight line K1 (solid line) represents the operating range B, which describes the defined range of values for the actual fill amount. Other correction parameters f are associated with the operating range B. z The injection quantity difference is obtained from the actual injection quantity, which has been determined with respect to the actual filling quantity in the relevant operating range B.
[0060] These other correction parameters are determined by the observed actual fill volume F for the operating range. ist (The diagram shows circle O) obtained from the actual filling amount F. ist In this process, representative values can be determined by identifying the centroids (diamond-shaped) of relevant clusters using appropriate clustering methods. Other corresponding correction parameters can also be determined by averaging the injection quantity differences within the operating range. These other correction parameters f are obtained directly during additive loading and by correspondingly considering the average actual injection quantity within the operating range during multiplicative loading. z .
[0061] When applying clustering methods, the measurement points of the actual injection volume within a running range are clustered using clustering methods, and the corresponding centroids are determined. The actual injection volume value of the centroid and the expected injection volume are compared with the actual filling volume F of the centroid. ist The deviation is expressed as the injection quantity difference: This injection quantity difference is used to determine other correction parameters f. z The foundation.
[0062] For each operating range B, adjustments to other correction parameters f can be performed continuously. z The determination and matching of.
[0063] With the help of diagnostic block 30, other calibration parameters can be compared with thresholds for the operating range, and if the value of another calibration parameter in one of the operating ranges exceeds the threshold given for this purpose, the error can be signaled.
Claims
1. A method for operating an internal combustion engine (2) by means of adjusting the air-fuel ratio of an air-fuel mixture, the method comprising the following steps: - Provides the actual λ value (Lambda) that illustrates the current air-fuel ratio. ist ), and provide the expected λ value that illustrates the desired air-fuel ratio; - Based on the actual λ value (Lambda) ist ) and the expected λ value (Lambda) soll This is used to adjust the expected injection quantity (MV) in order to determine the total amount of fuel (MG) to be delivered. - From the measured or simulated actual air filling volume (F ist In the relevant pre-control, based on at least one correction parameter (k) off k F The expected injection quantity (MV) is determined, where the air fill quantity represents the air delivered to the cylinder, wherein the measured or simulated actual air fill quantity (F) ist ) or determined by the actual air filling amount (F) ist The derived fuel quantity is loaded with at least one correction parameter (k). off k F In order to obtain the desired injection volume; In addition, based on the operating range of the internal combustion engine (2), other correction parameters (f) are provided. z The measured or simulated actual air filling volume (F) ist ) or the expected injection volume (MV) is loaded with the other correction parameters (f z This is to compensate for nonlinear errors when setting the air-fuel ratio.
2. The method according to claim 1, wherein, The internal combustion engine (2) is a gasoline engine.
3. The method according to claim 1, wherein, The at least one correction parameter (k) off k F This includes corrected offset (k) off ) and / or correction factor (k F ).
4. The method according to claim 1, wherein, The actual air filling volume (F) measured or simulated. ist ), determine the operating range, such that the other correction parameters (f z ) and the measured or simulated actual air filling volume (F) ist )related.
5. The method according to claim 1, wherein, The other correction parameters (f) are considered with the following weights. z The weight at the boundary of the corresponding operating range (B) is lower than the weight in the core area of the corresponding operating range (B).
6. The method according to claim 5, wherein, The other correction parameters (f) can be considered by applying a Gaussian function or a hat function. z ).
7. The method according to claim 5, wherein, For the other correction parameters (f) z Time filtering is performed to smooth the correction over time.
8. The method according to claim 7, wherein, Using a PT1 filter to correct the other correction parameters (f) z Time filtering is performed.
9. The method according to any one of claims 1 to 8, wherein, The actual air filling volume (F) determined for the corresponding operating range ist In the case of ), periodically or continuously based on the measured or simulated actual injection volume (M ist To adapt to the other correction parameters (f) z ).
10. The method according to claim 9, wherein, According to the actual injection quantity (M) in the operating range (B) ist The deviation between the average value of ) and the average value of the expected injection quantity is used to adjust the other correction parameters (f) z (Adaptation) 11. The method according to claim 9, wherein, Based on the actual injection volume (M) of the center of mass within the operating range (B). ist The deviation between the expected injection amount and the other correction parameters (f) are adjusted accordingly. z (Adaptation) 12. The method according to any one of claims 1 to 8, wherein, The other correction parameters (f) z ) are compared with a pre-given threshold for the operating range (B), and if the other correction parameter (f) is in one of the operating ranges z If the value of ) exceeds a pre-defined threshold, an error is signaled.
13. An apparatus for operating an internal combustion engine (2) by means of adjusting the air-fuel ratio of an air-fuel mixture, wherein the apparatus is configured to: - Provides the actual λ value (Lambda) that illustrates the current air-fuel ratio. ist ), and provide the expected λ value that illustrates the desired air-fuel ratio; - Based on the actual λ value (Lambda) ist The expected injection quantity (MV) is adjusted using the expected λ value to determine the total fuel quantity (MG) to be delivered. - From the measured or simulated actual air filling volume (F ist In the relevant pre-control, based on at least one correction parameter (k) off k F The expected injection quantity (MV) is determined, where the air fill quantity represents the air delivered to the cylinder, wherein the measured or simulated actual air fill quantity (F) ist ) or determined by the actual air filling amount (F) ist The derived fuel quantity is loaded with at least one correction parameter in order to obtain the expected injection quantity; In addition, based on the operating range (B) of the internal combustion engine (2), other correction parameters (f) are provided. z The measured or simulated actual air filling volume (F) ist ) or the expected injection volume (MV) is loaded with the other correction parameters (f z This is to compensate for nonlinear errors when setting the air-fuel ratio.
14. The device according to claim 13, wherein, The internal combustion engine (2) is a gasoline engine.
15. The device according to claim 13, wherein, The at least one correction parameter (k) off k F This includes corrected offset (k) off ) and / or correction factor (k F ).
16. A computer program product comprising instructions that, when implemented by a computer, cause the computer to perform the steps of the method according to any one of claims 1 to 12.
17. A machine-readable storage medium comprising instructions that, when executed by a computer, cause the computer to perform the steps of the method according to any one of claims 1 to 12.