An engine friction work estimation method, device and electronic equipment

Abstract

This invention discloses a method, device, and electronic equipment for estimating engine friction work. The method includes: inputting environmental correction parameters into a preset environmental correction model to obtain environmental correction coefficients; inputting vehicle state correction parameters into a preset vehicle state correction model to obtain vehicle state correction coefficients; determining the engine's basic friction work based on the engine state parameters; determining the in-cylinder explosion pressure correction coefficient based on the engine's in-cylinder explosion pressure; and obtaining the engine's friction work based on the environmental correction coefficients, the vehicle state correction coefficients, the engine's basic friction work, and the in-cylinder explosion pressure correction coefficient. This method can significantly improve the accuracy of friction work estimation under all environmental conditions and complex driving conditions, providing a more accurate data foundation for engine torque control and fuel optimization.

Description

Technical Field

[0001] This invention relates to the field of vehicle engine control technology, and in particular to a method, device, and electronic equipment for estimating engine friction work. Background Technology

[0002] Engine friction work refers to the power or work consumed by the relative motion of moving parts such as the crankshaft and connecting rod mechanism, valve train, various rotating bearings and accessory systems during engine operation. The accuracy of its value directly affects the output accuracy of the engine's effective torque, the assessment of thermal efficiency, and the control effect of fuel consumption.

[0003] Currently, in the field of engine control, the acquisition of frictional work mainly relies on bench test calibration methods. Specifically, by using a dynamometer to tow the engine backwards, mechanical losses are measured under different speeds and temperatures. Based on this, a steady-state frictional work MAP table is generated with engine speed, coolant temperature, and oil temperature as input parameters. In actual vehicle operation, the engine electronic control unit (ECU) obtains the frictional work under the current operating conditions through a table lookup method for torque control and fuel injection control.

[0004] However, the above-mentioned scheme still has certain limitations in practical applications. Its estimation accuracy is limited by the range of operating conditions, making it difficult to maintain ideal control effects under all environmental conditions and complex driving conditions, which restricts further optimization of engine torque control and fuel economy. Summary of the Invention

[0005] To improve the accuracy of engine friction work estimation under all environmental conditions and complex driving conditions, this invention provides an engine friction work estimation method, device, and electronic equipment.

[0006] In a first aspect, embodiments of the present invention provide a method for estimating engine friction work, which may include: Input the environmental correction parameters into the preset environmental correction model to obtain the environmental correction coefficients; Input the vehicle state correction parameters into the preset vehicle state correction model to obtain the vehicle state correction coefficients; Determine the engine's basic frictional work based on engine state parameters; Determine the in-cylinder explosion pressure correction coefficient based on the engine in-cylinder explosion pressure. The engine friction work is obtained based on the environmental correction coefficient, the vehicle state correction coefficient, the engine basic friction work, and the in-cylinder explosion pressure correction coefficient.

[0007] In one or more optional embodiments of this application, after obtaining the engine friction work, the method further includes: The measured frictional work is obtained based on the measured effective work and indicated work of the engine. Based on the measured friction work and the engine friction work, the prediction error is obtained; If the absolute value of the prediction error is greater than a preset error threshold, the preset environment correction model and the preset vehicle state correction model are iteratively corrected based on the prediction error until the absolute value of the prediction error recalculated after correction is less than or equal to the preset error threshold.

[0008] In one or more optional embodiments of this application, the environmental correction parameters include ambient atmospheric temperature, atmospheric pressure, altitude, and relative humidity. The step of inputting environmental correction parameters into a preset environmental correction model to obtain environmental correction coefficients includes: The ambient air temperature, atmospheric pressure, altitude, and relative humidity are input into the preset environmental correction model to obtain the environmental correction coefficient.

[0009] In one or more optional embodiments of this application, the vehicle state correction parameters include vehicle speed, longitudinal acceleration, load, and road rolling resistance. The step of inputting vehicle state correction parameters into a preset vehicle state correction model to obtain vehicle state correction coefficients includes: The vehicle speed, longitudinal acceleration, load, and road rolling resistance are input into the preset vehicle state correction model to obtain the vehicle state correction coefficient.

[0010] In one or more optional embodiments of this application, the engine status parameters include engine speed, engine oil temperature, and coolant temperature. The determination of the engine's basic frictional work based on engine state parameters includes: Based on the engine speed, the oil temperature, and the coolant temperature, a preset steady-state friction work lookup table is retrieved to obtain the engine's basic friction work; wherein, the preset steady-state friction work lookup table is used to characterize the correspondence between engine speed, oil temperature, coolant temperature, and engine's basic friction work.

[0011] In one or more optional embodiments of this application, after obtaining the engine friction work, the method further includes: Based on the engine friction work and the engine crankshaft angular velocity, the engine friction torque is obtained; The target indicated torque is determined based on the target effective torque and the engine friction torque; wherein, the target effective torque represents the net torque output by the engine crankshaft based on the driver's acceleration intention. The engine is controlled based on the target indicated torque.

[0012] In one or more optional embodiments of this application, the engine friction work is obtained based on the environmental correction coefficient, the vehicle state correction coefficient, the engine base friction work, and the in-cylinder combustion pressure correction coefficient, including: The engine friction work is obtained by multiplying the environmental correction coefficient, the vehicle state correction coefficient, the engine basic friction work, and the in-cylinder explosion pressure correction coefficient.

[0013] Secondly, embodiments of the present invention provide an engine friction work estimation device, which may include: The environmental correction module is used to input environmental correction parameters into a preset environmental correction model to obtain environmental correction coefficients. The vehicle state correction module is used to input vehicle state correction parameters into a preset vehicle state correction model to obtain vehicle state correction coefficients. The basic friction work determination module is used to determine the basic friction work of the engine based on engine state parameters. The in-cylinder combustion pressure correction module is used to determine the in-cylinder combustion pressure correction coefficient based on the engine's in-cylinder combustion pressure. The calculation module is used to obtain the engine friction work based on the environmental correction coefficient, the vehicle state correction coefficient, the engine basic friction work, and the in-cylinder explosion pressure correction coefficient.

[0014] Thirdly, embodiments of the present invention provide a computer-readable storage medium having a computer program / instruction stored thereon, which, when executed by a processor, implements the engine friction work estimation method described above.

[0015] Fourthly, embodiments of the present invention provide a computer program product, including a computer program / instruction, which, when executed by a processor, implements the engine friction work estimation method as described above.

[0016] Fifthly, embodiments of the present invention provide a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the engine friction work estimation method as described above.

[0017] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following: This invention provides a method for estimating engine friction work. By introducing environmental and vehicle state correction coefficients, this method corrects for friction work deviations caused by external environmental conditions and dynamic vehicle states, building upon the existing basic engine friction work. Furthermore, it utilizes an in-cylinder combustion pressure correction coefficient to compensate for the influence of combustion pressure on the friction state of moving parts. This expands the friction work estimation model from a traditional single-dimensional static lookup table to a multi-dimensional joint estimation. Compared to existing solutions, this significantly improves the accuracy of friction work estimation under all environmental conditions and complex driving conditions, providing a more accurate data foundation for engine torque control and fuel optimization.

[0018] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings.

[0019] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a flowchart illustrating the engine friction work estimation method provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the engine friction work estimation device provided in an embodiment of the present invention. Detailed Implementation

[0021] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0022] The inventors discovered that in existing technologies, the acquisition of frictional work mainly relies on bench test calibration methods. Specifically, by using a dynamometer to tow the engine, mechanical losses are measured under different speeds and temperatures, and a steady-state frictional work MAP table is calibrated based on this, using engine speed, coolant temperature, and oil temperature as input parameters. In actual vehicle operation, the engine electronic control unit obtains the frictional work under the current operating conditions by looking up the table, which is used for torque control and fuel injection control. However, this method still has certain limitations in practical applications. Its estimation accuracy is constrained by the range of operating conditions covered, making it difficult to maintain ideal control effects under all environmental conditions and complex driving conditions, thus restricting further optimization of engine torque control and fuel economy. Based on this, the inventors, through further research and development, have created this invention, providing an engine frictional work estimation method, device, and electronic equipment.

[0023] Example 1 Embodiment 1 of the present invention provides a method for estimating engine friction work, referring to... Figure 1 As shown, the method may include the following steps S101-S105: S101: Input the environmental correction parameters into the preset environmental correction model to obtain the environmental correction coefficients.

[0024] S102: Input the vehicle state correction parameters into the preset vehicle state correction model to obtain the vehicle state correction coefficients.

[0025] S103: Determine the engine's basic frictional work based on engine state parameters.

[0026] S104: Determine the in-cylinder explosion pressure correction coefficient based on the engine in-cylinder explosion pressure.

[0027] S105: Based on the environmental correction coefficient, vehicle condition correction coefficient, engine basic friction work, and in-cylinder explosion pressure correction coefficient, the engine friction work is obtained.

[0028] This invention provides a method for estimating engine friction work. By introducing environmental and vehicle state correction coefficients, this method corrects for friction work deviations caused by external environmental conditions and dynamic vehicle states, building upon the existing basic engine friction work. Furthermore, it utilizes an in-cylinder combustion pressure correction coefficient to compensate for the influence of combustion pressure on the friction state of moving parts. This expands the friction work estimation model from a traditional single-dimensional static lookup table to a multi-dimensional joint estimation. Compared to existing solutions, this significantly improves the accuracy of friction work estimation under all environmental conditions and complex driving conditions, providing a more accurate data foundation for engine torque control and fuel optimization.

[0029] In step S101 above, environmental correction parameters are input into a preset environmental correction model to obtain environmental correction coefficients. These environmental correction parameters include ambient air temperature, atmospheric pressure, altitude, and relative humidity.

[0030] Specifically, this can be achieved by inputting ambient atmospheric temperature, atmospheric pressure, altitude, and relative humidity into a preset environmental correction model to obtain environmental correction coefficients. After the preset environmental correction model outputs these environmental correction coefficients, they will be used in subsequent steps, along with the engine's basic friction work, vehicle condition correction coefficients, and in-cylinder combustion pressure correction coefficients, to participate in the real-time estimation of friction work. The environmental correction coefficients are used to correct for deviations in friction work caused by external environmental conditions, such as oil viscosity, lubrication status of moving parts, and intake air density.

[0031] The preset environmental correction model can be established in various ways, such as modeling based on physical mechanisms or based on experimental data.

[0032] Specifically, the pre-defined environmental correction model can be established using a physical mechanism-based modeling method. According to physical mechanisms, environmental parameters such as ambient temperature, atmospheric pressure, altitude, and relative humidity affect engine friction work primarily by altering oil viscosity and the lubrication state of moving parts. When ambient temperature decreases, oil viscosity increases, increasing oil film resistance between moving parts and leading to increased friction work. When ambient pressure decreases or altitude increases, intake air density decreases, changing the combustion state in the cylinder and affecting the lubrication conditions between piston rings and cylinder liners. Changes in relative humidity affect the water vapor content in the intake air, influencing the thermodynamic properties of combustion products and indirectly altering friction work. Based on these physical mechanisms, a functional relationship between environmental correction coefficients and various environmental correction parameters can be established, for example, using a multinomial regression model or an exponential model. The basic structure of the model is determined through theoretical analysis, and the model includes several undetermined coefficients. By inputting ambient temperature, atmospheric pressure, altitude, and relative humidity into the pre-defined environmental correction model, the environmental correction coefficients can be obtained.

[0033] The pre-defined environmental correction model can also be established using a calibration method based on experimental data. In engine bench testing, using an environmental simulation chamber or high-altitude environmental test rig, different ambient atmospheric temperatures, atmospheric pressures, altitudes, and relative humidity conditions are set. Under each condition, the mechanical losses are measured by reversing the engine using a dynamometer at different speeds and temperatures. The results are then compared with measurements under standard environmental conditions to calculate the friction work correction coefficients for each environmental condition. A calibration dataset is formed using ambient atmospheric temperature, atmospheric pressure, altitude, and relative humidity as inputs and the measured correction coefficients as outputs. Based on this, a multivariate nonlinear regression method is used to fit the calculation model for the environmental correction coefficients; alternatively, an artificial neural network method is used, using the calibration dataset as training samples, to establish a neural network model with ambient atmospheric temperature, atmospheric pressure, altitude, and relative humidity as input layers and environmental correction coefficients as output layers. The network weights are trained using an error backpropagation algorithm until the error between the model output and the calibration data converges to a pre-defined range.

[0034] The pre-defined environmental correction model can also be established using a hybrid modeling approach that combines physical mechanisms with experimental data. First, a theoretical model framework containing undetermined coefficients is constructed based on tribological principles. Then, using measured data obtained from bench calibration tests, parameter identification methods are employed to determine the undetermined coefficients in the model. Parameter identification can utilize methods such as least squares, Gauss-Newton iteration, or recursive least squares algorithms.

[0035] In step S102 above, vehicle state correction parameters are input into a preset vehicle state correction model to obtain vehicle state correction coefficients. These vehicle state correction parameters include vehicle speed, longitudinal acceleration, load, and road rolling resistance.

[0036] Specifically, vehicle speed, longitudinal acceleration, load, and road rolling resistance can be input into a preset vehicle state correction model to obtain vehicle state correction coefficients. After the preset vehicle state correction model outputs the vehicle state correction coefficients, these coefficients will be used in subsequent steps, along with the engine's basic friction work, environmental correction coefficients, and in-cylinder combustion pressure correction coefficients, to participate in the real-time estimation of friction work. The vehicle state correction coefficients are used to correct for the impact of factors such as engine load changes, increased inertial drag, and fluctuations in accessory power consumption caused by the dynamic driving state of the vehicle on friction work, so that the estimated friction work can reflect the dynamic changes of the vehicle in actual road driving.

[0037] The method of establishing the preset vehicle state correction model is similar to that of the preset environment correction model in step S101 above. It can also be established in a variety of ways, such as modeling based on physical mechanisms or establishing it based on experimental data.

[0038] The pre-defined vehicle state correction model can be established using a physics-based modeling method. The impact of vehicle dynamic driving state on engine friction work is mainly reflected in three aspects: First, changes in vehicle speed directly affect engine speed and crankshaft angular velocity, thereby altering the relative speed of moving parts and the dynamic pressure effect of the oil film, causing friction work to change nonlinearly with vehicle speed; Second, longitudinal acceleration reflects the transient acceleration and deceleration process of the vehicle. During acceleration, the crankshaft angular acceleration increases, the inertial resistance of moving parts rises, and the lateral force between the piston and cylinder liner changes, resulting in a momentary increase in friction work; Third, when the load increases, the overall vehicle driving resistance increases, the engine needs to output more power to maintain the vehicle speed, the in-cylinder explosion pressure increases, the normal pressure of the piston rings on the cylinder wall increases, and the friction work increases accordingly. At the same time, the increased load also changes the vehicle vibration characteristics, indirectly affecting the friction state of bearings and moving parts; Road rolling resistance directly determines the power level required for the engine to overcome road resistance. When rolling resistance increases, the engine load increases, and the load borne by each moving part also increases accordingly. Based on the aforementioned physical mechanisms, a functional relationship can be established between the vehicle state correction coefficient and vehicle speed, longitudinal acceleration, load, and road rolling resistance. This can be achieved, for example, using a multiple regression model or a nonlinear function. The basic structure of the model is determined through theoretical analysis, and the model contains several undetermined coefficients. By inputting vehicle speed, longitudinal acceleration, load, and road rolling resistance into a preset vehicle state correction model, the vehicle state correction coefficient can be obtained.

[0039] The pre-defined vehicle state correction model can also be established using a calibration method based on experimental data. In whole-vehicle swivel bench tests or actual road tests, different operating conditions are set up, including vehicle speed, longitudinal acceleration, load, and road rolling resistance. Real-time engine operating data is collected under each condition via the engine ECU and the Controller Area Network Bus (CAN). The difference between indicated work and effective work is used to infer the measured friction work, thereby calculating the friction work correction coefficient for each vehicle state condition. A calibration dataset is formed using vehicle speed, longitudinal acceleration, load, and road rolling resistance as inputs and the measured correction coefficients as outputs. Based on this, a multivariate nonlinear regression method is used to fit and obtain the calculation model for the vehicle state correction coefficients; alternatively, an artificial neural network method is used, using the calibration dataset as training samples, to establish a neural network model with vehicle speed, longitudinal acceleration, load, and road rolling resistance as input layers and vehicle state correction coefficients as output layers. The network weights are trained using an error backpropagation algorithm until the error between the model output and the calibration data converges to a pre-defined range.

[0040] The pre-defined vehicle state correction model can also be established using a hybrid modeling approach that combines physical mechanisms with experimental data. First, a theoretical model framework for vehicle state correction coefficients, including undetermined coefficients, is constructed based on dynamic principles. Then, measured data obtained from bench or road calibration tests are used to determine the undetermined coefficients in the model using parameter identification methods. Parameter identification can employ methods such as least squares, Gauss-Newton iteration, or recursive least squares algorithms. After inputting vehicle speed, longitudinal acceleration, load, and road rolling resistance into the pre-defined vehicle state correction model, the model outputs the vehicle state correction coefficients.

[0041] In step S103 above, the basic frictional work of the engine is determined based on the engine state parameters. These engine state parameters include engine speed, engine oil temperature, and coolant temperature.

[0042] Specifically, this can be achieved by retrieving a preset steady-state friction work lookup table based on engine speed, oil temperature, and coolant temperature to obtain the engine's basic friction work. The preset steady-state friction work lookup table is used to characterize the correspondence between engine speed, oil temperature, coolant temperature, and the engine's basic friction work.

[0043] The preset steady-state friction work reference table is obtained through pre-calibration via engine bench testing. Under various operating conditions—combinations of engine speed, oil temperature, and coolant temperature—the engine's mechanical losses are measured using a dynamometer with a reverse drag method. The friction work value corresponding to each operating condition is calculated. A three-dimensional map table, i.e., the preset steady-state friction work reference table, is constructed using engine speed, oil temperature, and coolant temperature as input dimensions and friction work as the output dimension. During actual operation, the ECU collects the current engine speed, oil temperature, and coolant temperature in real time. It then searches the preset steady-state friction work reference table using these three values. If the current operating condition falls between the calibration points, a multi-dimensional linear interpolation method is used to calculate the corresponding friction work value, outputting the engine's basic friction work. This basic friction work reflects the baseline friction loss level of the engine under the current speed and thermal conditions, without the influence of environmental or vehicle dynamic factors.

[0044] In step S104 above, the in-cylinder explosion pressure correction coefficient is determined based on the engine in-cylinder explosion pressure.

[0045] Specifically, the in-cylinder combustion pressure can be input into a preset in-cylinder combustion pressure correction model to obtain an in-cylinder combustion pressure correction coefficient. This coefficient is used to compensate for the additional effects of high-pressure combustion gases on the piston rings and cylinder liners during combustion. When the in-cylinder combustion pressure increases, the high-pressure gases act on the back of the piston rings, pressing them tightly against the cylinder wall, increasing the normal pressure between the piston rings and cylinder liners, thereby increasing frictional resistance.

[0046] The preset in-cylinder combustion pressure correction model can be pre-calibrated through bench testing. On an engine bench, keeping the engine speed and temperature constant, the in-cylinder combustion pressure is changed by adjusting the fuel injection quantity or intake pressure. Engine mechanical losses are measured at each pressure point. Using the mechanical losses under standard conditions as a benchmark, the friction work correction coefficient corresponding to each combustion pressure is calculated, establishing a correspondence between the in-cylinder combustion pressure and the correction coefficient. This correspondence can be stored in MAP table format or fitted into an empirical formula with in-cylinder combustion pressure as the independent variable. During actual operation, the ECU collects cylinder pressure sensor signals in real time or estimates the current in-cylinder combustion pressure based on the fuel injection quantity and engine speed, inputting this data into the preset in-cylinder combustion pressure correction model. The model then outputs the in-cylinder combustion pressure correction coefficient.

[0047] In step S105 above, the engine friction work is obtained based on the environmental correction coefficient, the vehicle state correction coefficient, the engine basic friction work, and the in-cylinder explosion pressure correction coefficient.

[0048] Specifically, the engine friction work can be obtained by multiplying the environmental correction factor, vehicle condition correction factor, engine basic friction work, and in-cylinder combustion pressure correction factor. This is illustrated in Formula 1 below:

[0049] In the formula, Wf For the friction work of the engine, Wf_base For the basic frictional work of the engine, Kenv This is the environmental correction factor. Kveh This is the vehicle condition correction factor. Kcy This is the correction factor for the in-cylinder combustion pressure.

[0050] Among them, the engine basic friction work reflects the benchmark friction loss of the engine under standard environmental conditions and without the influence of vehicle load; the environmental correction coefficient corrects the influence of external environmental conditions on friction work; the vehicle state correction coefficient corrects the influence of the dynamic driving state of the whole vehicle on friction work; and the in-cylinder combustion pressure correction coefficient compensates for the additional influence of high-pressure gas in the cylinder on the friction state of piston rings and cylinder liners.

[0051] The engine friction work under the current operating condition is obtained by multiplying the above four parameters. Since each correction coefficient independently characterizes the influencing factors of friction work from different dimensions, the multiplication form can concisely achieve multi-factor joint correction. Compared with the traditional single-dimensional lookup table scheme, this method extends the estimation of engine friction work from static open-loop to multi-dimensional coupled estimation. After obtaining the engine friction work, the ECU can output the estimated value to the engine torque control and fuel injection control modules for subsequent target indicated torque calculation and fuel injection quantity control.

[0052] In this embodiment of the application, after completing step S105 and obtaining the engine friction work, step S106 is further included, specifically including the following steps S1061-S1063: S1061: Based on the measured effective work and indicated work of the engine, the measured friction work is obtained.

[0053] Specifically, this can be achieved by the engine ECU collecting the engine's effective work and indicated work in real time. Effective work can be directly measured by a torque sensor at the crankshaft flywheel end, or indirectly estimated by crankshaft speed fluctuations. Indicated work can be obtained by collecting instantaneous pressure signals within the cylinder from a cylinder pressure sensor and integrating the pressure-volume curve, or estimated from parameters such as fuel injection quantity and combustion efficiency. After obtaining the effective work and indicated work within the same working cycle, the effective work is subtracted from the indicated work to obtain the measured frictional work.

[0054] It should be noted that the measured friction work reflects the actual friction loss that has occurred in the engine during the current working cycle. In other words, this value is calculated back from sensor signals or parameters after combustion has completed, and therefore has a time lag. During actual engine control, when it is necessary to determine the current injection quantity or torque output, the measured friction work at that moment has not yet been generated and cannot be known in advance. Therefore, it is necessary to rely on the estimation model to predict the engine friction work before the control command is issued, i.e., the engine friction work obtained in step S105. The measured friction work is not directly used for control at the current moment, but rather serves as a reference for subsequently evaluating the accuracy of the estimation model output, used to correct the model parameters for the next moment or subsequent operating conditions. The measured friction work includes the actual friction loss under the combined effects of all factors such as environmental conditions, vehicle condition, engine wear, and oil aging, and can objectively reflect the true friction level under the current operating conditions.

[0055] S1062: The prediction error is obtained based on the measured friction work and engine friction work.

[0056] Specifically, the measured friction work can be compared with the engine friction work estimated in step S105. Subtracting the engine friction work from the measured friction work yields the prediction error. The sign and magnitude of this prediction error reflect the direction and degree of deviation between the current friction work estimation model (including steps S101-S105 above) and the actual operating conditions. If the prediction error is zero or close to zero, it indicates that the current friction work estimation model has high accuracy; if the prediction error deviates significantly from zero, it indicates that the current friction work estimation model has a systematic bias and needs to be corrected.

[0057] In practical engineering applications, the measured friction work itself contains certain measurement noise and random errors due to factors such as sensor measurement accuracy and combustion cycle fluctuations. If every random fluctuation in the measurement value is treated as a model deviation for correction, the model parameters will be repeatedly adjusted with the noise, which will reduce the estimation accuracy and even cause control oscillations. To address this, this application introduces a dead zone mechanism, with a preset error threshold serving as the dead zone boundary. When the absolute value of the prediction error is less than or equal to the preset error threshold, the error is considered a normal deviation within the range of measurement noise and random fluctuations. The accuracy of the current friction work estimation model meets the requirements, so correction is abandoned, and the model parameters remain unchanged. Only when the absolute value of the prediction error exceeds the preset error threshold is the model considered to have a substantial systematic deviation, and the iterative correction process is initiated. For example, setting the preset error threshold to ±2% of the measured friction work means that correction is not triggered within the range of ±2%. This 2% threshold absorbs the unreliability caused by sensor accuracy limitations and random combustion fluctuations, thereby ensuring that the correction process is not interfered with by measurement noise and ensuring the stability and effectiveness of model correction.

[0058] It should be noted that the aforementioned current friction work estimation model is a complete model constituted by steps S101 to S105 of the embodiments of this application. This model sequentially obtains the environmental correction coefficient, the vehicle state correction coefficient, the engine's basic friction work, and the in-cylinder explosion pressure correction coefficient, ultimately multiplying the above four parameters to obtain the engine friction work. Therefore, the prediction error mentioned in this step is essentially used to evaluate the output accuracy of the overall model constituted by the aforementioned steps S101 to S105.

[0059] The iterative correction based on the prediction error in the subsequent step S1063 is also performed on a part of the overall model.

[0060] S1063: If the absolute value of the prediction error is greater than the preset error threshold, the preset environment correction model and the preset vehicle state correction model are iteratively corrected based on the prediction error until the absolute value of the prediction error recalculated after correction is less than or equal to the preset error threshold.

[0061] Specifically, this method can pre-store a preset error threshold, which can be set according to the engine control accuracy requirements and sensor measurement accuracy. For example, it can be set to ±2% of the measured friction work.

[0062] The absolute value of the prediction error calculated in step S1062 is compared with the preset error threshold. If the absolute value of the prediction error is less than or equal to the preset error threshold, it indicates that the accuracy of the current friction work estimation model meets the requirements and no correction is needed, and the original model parameters remain unchanged. If the absolute value of the prediction error is greater than the preset error threshold, it indicates that the deviation of the current estimation model exceeds the allowable range and the model needs to be corrected.

[0063] At this point, the preset environment correction model and the preset vehicle state correction model are iteratively corrected based on the prediction error. Specifically, the Recursive Least Squares (RLS) algorithm can be used as an adaptive correction algorithm. With the goal of minimizing the prediction error, the parameters in the preset environment correction model and the preset vehicle state correction model are continuously updated through online recursive calculation, so that the engine friction work output by the model gradually approaches the measured friction work.

[0064] During the correction process, after each iteration, the environmental correction coefficients and vehicle state correction coefficients output by the corrected model are recalculated. Then, step S105 is executed again to obtain the updated engine friction work estimate. Steps S1061 and S1062 are then executed again to calculate the new prediction error, and the absolute value of the new prediction error is compared with a preset error threshold. The above iterative correction process is repeated until the absolute value of the recalculated prediction error is less than or equal to the preset error threshold. At this point, the correction stops, and the corrected preset environmental correction model and preset vehicle state correction model are obtained, thus yielding the corrected friction work estimation model.

[0065] It should be noted that the iterative correction in this step is limited to the preset environmental correction model and the preset vehicle state correction model in the friction work estimation model, and does not correct the in-cylinder explosion pressure correction coefficient, because the influence of in-cylinder explosion pressure on friction work follows a fixed physical law and does not change with environmental aging and wear and other time factors.

[0066] In this embodiment of the application, after completing the above step S105 and obtaining the engine friction work, step S107 is further included, specifically including the following steps S1071-S1073: S1071: Based on the engine friction work and the engine crankshaft angular velocity, the engine friction torque is obtained.

[0067] Specifically, this can be achieved by acquiring the engine crankshaft angular velocity, which can be measured by a crankshaft position sensor. In thermodynamics and engine control principles, the relationship between power or work and torque is: torque equals power or work divided by angular velocity. Therefore, dividing the engine friction work estimated in step S105 by the crankshaft angular velocity yields the engine friction torque.

[0068] The engine friction torque corresponds to the friction work, reflecting the equivalent torque consumed by the engine under current operating conditions to overcome the frictional resistance of various moving parts. Its physical meaning is the same as that of friction work, but it is expressed in the form of torque. Since the torque coordination, fuel injection control, and idle speed control modules inside the engine ECU all perform calculations and decisions based on torque parameters, the estimation result after converting friction work into friction torque can be directly used in subsequent engine control calculations.

[0069] S1072: Determine the target indicated torque based on the target effective torque and the engine friction torque. The target effective torque represents the net torque output by the engine crankshaft, determined based on the driver's acceleration intention.

[0070] Specifically, the target effective torque can be calculated in real time by an internal torque demand arbitration module based on the driver's input signal to the accelerator pedal, combined with vehicle status information such as current speed, gear, vehicle load, and road conditions. The target effective torque represents the net torque value that the vehicle system expects to actually output from the engine crankshaft flywheel end, and is a comprehensive reflection of the driver's acceleration intention and the vehicle's status requirements.

[0071] However, the total torque actually generated by engine combustion is not entirely used for external output; a portion of the torque needs to overcome internal engine friction losses, namely the engine friction torque calculated in step S1071 above. Therefore, in order to ensure that the crankshaft flywheel end can ultimately output the target effective torque, the combustion process must generate a total torque greater than the target effective torque.

[0072] The target effective torque is added to the engine friction torque to obtain the target indicated torque. This target indicated torque represents the total torque required by the engine under current operating conditions to achieve the target effective torque output, and is the core basis for subsequent fuel injection quantity calculation and ignition control.

[0073] S1073: Engine based on target indicated torque control.

[0074] Specifically, the target indicated torque determined in step S1072 can be used as the control target, and the amount of fuel injection required to achieve the torque can be calculated.

[0075] Based on parameters such as current engine speed, intake air volume, air-fuel ratio, and ignition advance angle, a preset torque-fuel conversion model converts the target indicated torque into corresponding injection pulse width and injection timing, sending control commands to the injectors to achieve precise injection of the target fuel quantity. Simultaneously, the ignition advance angle and intake parameters are adjusted according to the target indicated torque and current operating conditions, ensuring that the indicated torque generated during combustion closely approximates the target indicated torque in real time. During actual engine operation, cylinder pressure and crankshaft speed signals are continuously monitored to assess whether the actual indicated torque reaches the target value, forming a closed-loop control of fuel injection and combustion. This ensures that the effective torque output from the crankshaft flywheel stably follows the driver's target effective torque requirement.

[0076] Through the above control process, the embodiment of this application feeds back the engine friction work estimated in step S105 to the engine's fuel injection control and torque control through a closed-loop control loop, realizing the bidirectional coupling between friction work estimation and engine control, so that the improvement in friction work estimation accuracy is directly converted into the improvement of engine torque control accuracy and fuel economy.

[0077] It should be noted that both steps S106 and S107 are executed after the engine friction work estimation value is obtained in step S105. Step S106 focuses on the adaptive correction of the friction work estimation model itself, which is a model-level optimization; step S107 focuses on using the estimation result to achieve real-time engine control, which is an application-level execution. The two steps are independent and parallel, both using the engine friction work output in step S105 as a prerequisite input, together constituting the complete flow of the friction work estimation model control in this embodiment.

[0078] Compared with the prior art, the embodiments of this application have the following beneficial effects: By introducing environmental correction coefficients and vehicle state correction coefficients respectively, the friction work estimation model is expanded from the traditional single-dimensional static table lookup to a multi-dimensional joint estimation that integrates environmental conditions, vehicle dynamic state, and engine operating state. Under complex working conditions such as high altitude, low temperature, heavy load, and transient acceleration and deceleration, the friction work estimation error is significantly reduced, and the estimation accuracy is greatly improved. Based on the high-precision friction work estimation value, it is further converted into friction torque and participates in the real-time calculation of the target indicated torque, which effectively improves the engine torque control accuracy and makes the fuel injection quantity control more precise, thereby reducing the overall vehicle fuel consumption. At the same time, due to the improvement in the accuracy of friction work estimation, the torque compensation under idling conditions is more accurate, the engine idling stability is improved, combustion is more complete, and pollutant emissions are correspondingly reduced.

[0079] Furthermore, this application introduces an online adaptive correction mechanism based on measured friction work, enabling the friction work estimation model to track changes caused by factors such as engine oil aging, component wear, and long-term operating condition drift. This ensures high estimation accuracy throughout the entire engine lifecycle and demonstrates self-learning and adaptive capabilities. All of the above steps can be implemented in software within the existing engine ECU, without requiring additional hardware sensors or modifications to the engine's structure. This results in low modification costs and demonstrates good engineering feasibility and widespread application value.

[0080] Example 2 Based on the same inventive concept, embodiments of the present invention also provide an engine friction work estimation device, referring to... Figure 2 As shown, the device includes: Environmental correction module 101 is used to input environmental correction parameters into a preset environmental correction model to obtain environmental correction coefficients; The vehicle state correction module 102 is used to input the vehicle state correction parameters into the preset vehicle state correction model to obtain the vehicle state correction coefficients. The basic friction work determination module 103 is used to determine the basic friction work of the engine based on the engine state parameters. The in-cylinder explosion pressure correction module 104 is used to determine the in-cylinder explosion pressure correction coefficient based on the engine in-cylinder explosion pressure. The calculation module 105 is used to obtain the engine friction work based on the environmental correction coefficient, the vehicle state correction coefficient, the engine basic friction work, and the in-cylinder explosion pressure correction coefficient.

[0081] Example 3 Based on the same inventive concept, embodiments of the present invention also provide a computer-readable storage medium storing a computer program / instructions thereon, which, when executed by a processor, implements the engine friction work estimation method as described in Embodiment 1 above.

[0082] Example 4 Based on the same inventive concept, embodiments of the present invention also provide a computer program product, including a computer program / instruction, which, when executed by a processor, implements the engine friction work estimation method as described in Embodiment 1 above.

[0083] Example 5 Based on the same inventive concept, embodiments of the present invention also provide a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the engine friction work estimation method as described in Embodiment 1 above.

[0084] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0085] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0086] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0087] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0088] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for estimating engine friction work, characterized in that, The method includes: Input the environmental correction parameters into the preset environmental correction model to obtain the environmental correction coefficients; Input the vehicle state correction parameters into the preset vehicle state correction model to obtain the vehicle state correction coefficients; Determine the engine's basic frictional work based on engine state parameters; Determine the in-cylinder explosion pressure correction coefficient based on the engine in-cylinder explosion pressure. The engine friction work is obtained based on the environmental correction coefficient, the vehicle state correction coefficient, the engine basic friction work, and the in-cylinder explosion pressure correction coefficient.

2. The method according to claim 1, characterized in that, After obtaining the engine friction work, the process also includes: The measured frictional work is obtained based on the measured effective work and indicated work of the engine. Based on the measured friction work and the engine friction work, the prediction error is obtained; If the absolute value of the prediction error is greater than a preset error threshold, the preset environment correction model and the preset vehicle state correction model are iteratively corrected based on the prediction error until the absolute value of the prediction error recalculated after correction is less than or equal to the preset error threshold.

3. The method according to claim 1, characterized in that, The environmental correction parameters include ambient atmospheric temperature, atmospheric pressure, altitude, and relative humidity. The step of inputting environmental correction parameters into a preset environmental correction model to obtain environmental correction coefficients includes: The ambient air temperature, atmospheric pressure, altitude, and relative humidity are input into the preset environmental correction model to obtain the environmental correction coefficient.

4. The method according to claim 1, characterized in that, The vehicle condition correction parameters include vehicle speed, longitudinal acceleration, load, and road rolling resistance; The step of inputting vehicle state correction parameters into a preset vehicle state correction model to obtain vehicle state correction coefficients includes: The vehicle speed, longitudinal acceleration, load, and road rolling resistance are input into the preset vehicle state correction model to obtain the vehicle state correction coefficient.

5. The method according to claim 1, characterized in that, The engine status parameters include engine speed, engine oil temperature, and coolant temperature. The determination of the engine's basic frictional work based on engine state parameters includes: Based on the engine speed, the oil temperature, and the coolant temperature, a preset steady-state friction work lookup table is retrieved to obtain the engine's basic friction work; wherein, the preset steady-state friction work lookup table is used to characterize the correspondence between engine speed, oil temperature, coolant temperature, and engine's basic friction work.

6. The method according to claim 1, characterized in that, After obtaining the engine friction work, the process also includes: Based on the engine friction work and the engine crankshaft angular velocity, the engine friction torque is obtained; The target indicated torque is determined based on the target effective torque and the engine friction torque; wherein, the target effective torque represents the net torque output by the engine crankshaft based on the driver's acceleration intention. The engine is controlled based on the target indicated torque.

7. The method according to claim 1, characterized in that, Based on the environmental correction coefficient, the vehicle state correction coefficient, the engine basic friction work, and the in-cylinder combustion pressure correction coefficient, the engine friction work is obtained, including: The engine friction work is obtained by multiplying the environmental correction coefficient, the vehicle state correction coefficient, the engine basic friction work, and the in-cylinder explosion pressure correction coefficient.

8. A device for estimating engine friction work, characterized in that, include: The environmental correction module is used to input environmental correction parameters into a preset environmental correction model to obtain environmental correction coefficients. The vehicle state correction module is used to input vehicle state correction parameters into a preset vehicle state correction model to obtain vehicle state correction coefficients. The basic friction work determination module is used to determine the basic friction work of the engine based on engine state parameters. The in-cylinder combustion pressure correction module is used to determine the in-cylinder combustion pressure correction coefficient based on the engine's in-cylinder combustion pressure. The calculation module is used to obtain the engine friction work based on the environmental correction coefficient, the vehicle state correction coefficient, the engine basic friction work, and the in-cylinder explosion pressure correction coefficient.

9. A computer-readable storage medium having a computer program / instructions stored thereon, characterized in that, When the computer program / instruction is executed by the processor, it implements the engine friction work estimation method according to any one of claims 1-7.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory. Its features are, The processor executes the computer program to implement the engine friction work estimation method according to any one of claims 1-7.

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