Engine cylinder head temperature sensing method with virtual reality fusion
By using a virtual-real fusion approach and adjusting model parameters with real-time engine data, the high cost and real-time performance issues of cylinder head temperature measurement are resolved. This enables rapid, accurate, and low-cost sensing of cylinder head temperature, supporting engine thermal management and life prediction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGXI YUCHAI MASCH CO LTD
- Filing Date
- 2026-01-29
- Publication Date
- 2026-06-12
AI Technical Summary
Existing technologies for measuring engine cylinder head temperature are costly, have poor durability, cannot operate in real time, involve large amounts of computation, and are difficult to dynamically adapt to different operating conditions in the engine controller.
By constructing a simplified model based on physical laws, dynamically adjusting model parameters using real-time engine operating data, and comparing it with measured temperatures, a virtual-real fusion perception of cylinder head temperature is achieved. This relies entirely on standard signals from the engine electronic control unit and requires no additional hardware sensors.
It enables rapid, accurate, and low-cost sensing of cylinder head temperature, is suitable for real-time operation in vehicle electronic control units, has high robustness and engineering practicality, and supports engine thermal management control and life prediction.
Smart Images
Figure CN122190903A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of engine design and manufacturing, and in particular to a method for sensing engine cylinder head temperature using a virtual-real integrated approach. Background Technology
[0002] Accurate sensing of engine cylinder head temperature is crucial for preventing knocking, optimizing ignition / injection strategies, protecting components, and achieving efficient thermal management. Existing technologies have the following main limitations:
[0003] 1. Direct temperature measurement method: Thermocouples are embedded in the cylinder head firing surface, which is costly, has poor durability, and is difficult to deploy in mass-produced vehicles.
[0004] 2. Computational Fluid Dynamics / Finite Element Method: Relies on accurate geometric and material models, involves large computational loads, and cannot be run in real time in engine controllers.
[0005] Therefore, there is an urgent need for a low-cost, computationally efficient method for real-time estimation of cylinder head temperature that can dynamically adapt to different engine operating conditions.
[0006] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention
[0007] The purpose of this invention is to provide a virtual-real integrated method for sensing engine cylinder head temperature. The "virtual" aspect of this method lies in constructing a simplified model based on physical laws; the "real" aspect lies in using real-time engine operating data to dynamically adjust the core parameters of the model, and ensuring the accuracy of the model by comparing it with the measured temperature. This method is entirely based on the standard signals already present in the engine electronic control unit, without the need for any additional hardware sensors.
[0008] To achieve the above objectives, this invention provides a virtual-real fusion method for sensing engine cylinder head temperature, comprising the following steps: signal acquisition and preprocessing, which includes real-time acquisition of various engine operating parameters, including engine speed, torque, coolant temperature, exhaust temperature, and exhaust flow rate, and calculating the steady-state exhaust temperature and exhaust flow rate corresponding to the real-time engine speed and torque; dynamic thermal inertia time constant calculation, which includes converting the steady-state exhaust temperature into a transient value matching the actual metal temperature change rate based on the thermal inertia of the cylinder head temperature response, and calculating the dynamic thermal inertia time constant; instantaneous exhaust temperature calculation, which involves performing a first-order inertial delay correction on the calculated steady-state exhaust temperature to obtain an instantaneous exhaust temperature that conforms to the physical transient process; cylinder head temperature calculation, which is based on the linear heat distribution assumption that the ratio of the difference between the cylinder head temperature and the coolant temperature to the exhaust temperature is constant under all engine operating conditions, and calculating the cylinder head temperature at the current moment; and output and application, outputting the real-time cylinder head temperature for engine thermal management control.
[0009] In a preferred embodiment, the engine speed, torque, and outlet water temperature can be directly read from various sensors of the engine. The exhaust temperature and exhaust flow rate can be obtained from the engine universal curve generated after the universal characteristic test is completed on the engine bench. The steady-state exhaust temperature and exhaust flow rate at different speeds and torques can be obtained by interpolation using the real-time engine speed and torque read from the engine.
[0010] In a preferred embodiment, the formula for calculating the dynamic thermal inertia time constant is as follows:
[0011] (1)
[0012] in, The thermal inertia time constant under rated operating conditions can be calibrated and confirmed using a test bench. The exhaust flow rate at the rated operating point can be obtained through bench testing. The exhaust flow rate at the current operating point is obtained by interpolation on the universal curve; K is the structural thermal resistance coefficient.
[0013] In a preferred embodiment, it can be seen from formula (1) that if = ,but = ;when < At that time, thermal inertia time constant An increase indicates a slower temperature response; conversely, a decrease indicates a decrease.
[0014] In a preferred embodiment, the formula for calculating the structural thermal resistance coefficient in formula (1) is as follows:
[0015] (2)
[0016] in, The highest exhaust temperature, This is the highest temperature of the cylinder head. The highest water temperature can be obtained through bench testing.
[0017] In a preferred embodiment, the discrete recursive formula for the exhaust temperature at the current moment is:
[0018] (3)
[0019] in, The exhaust temperature at the current moment. The exhaust temperature at the previous moment. The steady-state exhaust temperature is calculated using MAP interpolation, where Δt is the sampling period or calculation step size. The dynamic thermal inertia time constant calculated by formula (1) is Δt = 1 s. During the initialization of the calculation, It can be set to the value obtained from the current interpolation. .
[0020] In a preferred embodiment, based on the linear heat distribution assumption, the difference between cylinder head temperature and coolant temperature under all engine operating conditions ( ) and exhaust temperature ( The ratio of ) is constant, that is Then the cylinder head temperature at the current moment can be calculated using the following formula:
[0021] (4)
[0022] in, The current cylinder head temperature. This is the highest temperature of the cylinder head. The highest water temperature, The highest exhaust temperature, The exhaust temperature at the current moment. The water temperature at the current moment.
[0023] In a preferred embodiment, the real-time cylinder head temperature is output for engine thermal management control. Thermal management control includes controlling the operating strategy of the cooling system (electronic water pump, thermostat, and fan) to achieve precise cooling; or it is used to monitor thermal load and trigger engine torque reduction protection; or it is used to perform thermal fatigue damage calculation, carry out life prediction, and improve engine reliability.
[0024] Compared with existing technologies, the virtual-real fusion method for sensing engine cylinder head temperature of the present invention has the following beneficial effects: The present invention creatively proposes a real-time estimation method for engine cylinder head temperature that integrates steady-state data, dynamic physical models, and inherent structural characteristics. Its core lies in achieving rapid, accurate, and low-cost "virtual-real fusion" sensing of cylinder head metal temperature without a direct cylinder head temperature sensor through transformation and correction. The present invention utilizes experimental data covering all operating conditions and ensures the accuracy of transient processes through a physical model, making it more robust to extrapolation than purely data-driven models.
[0025] 1. A thermal inertia time constant that dynamically changes with exhaust flow rate was proposed and defined, which accurately characterizes the transient delay characteristics in the process of exhaust temperature transfer to the cylinder head.
[0026] 2. An indirect calculation model for cylinder head temperature based on the linear heat distribution assumption is established. This model bypasses complex three-dimensional heat conduction calculations, transforming the difficult-to-measure cylinder head metal temperature into a function of easily obtainable coolant temperature and a modified exhaust temperature. The formula is simple in form, requires minimal calibration, is highly practical for engineering applications, and has a very low computational load, making it ideal for real-time operation in vehicle electronic control units (ECUs).
[0027] 3. A three-level fusion sensing architecture of "steady-state data + dynamic correction + structural characteristics" is established, systematically integrating the above-mentioned inventions into a complete sensing process, achieving deep fusion of data and models. The first level, the data layer, utilizes the engine steady-state universal characteristic MAP (database) obtained from pre-experimentation to interpolate basic steady-state exhaust parameters based on real-time speed / torque. The second level, the dynamic correction layer, uses a dynamic thermal inertia time constant model to perform first-order inertial delay correction on the steady-state exhaust temperature, obtaining a "virtual" transient exhaust temperature that reflects the actual thermal inertia process. The third level, the physical conversion layer, uses a linear heat distribution model combined with the current coolant temperature ("real" sensor signal) to convert the corrected exhaust-side temperature, ultimately achieving low-cost indirect calculation of the final target, thus completely solving the technical challenge of "real-time cylinder head temperature sensing." Attached Figure Description
[0028] Figure 1 This is a logic block diagram of a sensing method according to an embodiment of the present invention. Detailed Implementation
[0029] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.
[0030] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.
[0031] like Figure 1 As shown, the virtual-real fusion engine cylinder head temperature sensing method according to a preferred embodiment of the present invention includes the following steps: signal acquisition and preprocessing S1, which includes real-time acquisition of various operating parameters of the engine, including engine speed n, torque Md, coolant temperature Tw, exhaust temperature Tp, and exhaust flow rate m, and calculating the steady-state exhaust temperature and exhaust flow rate corresponding to the real-time engine speed and torque through the operating parameters; dynamic thermal inertia time constant calculation S2, which includes converting the steady-state exhaust temperature into a transient value that matches the actual metal temperature change rate based on the thermal inertia of the cylinder head temperature response, and calculating the dynamic thermal inertia time constant; instantaneous exhaust temperature calculation S3, performing a first-order inertial delay correction on the calculated steady-state exhaust temperature to obtain an instantaneous exhaust temperature that conforms to the physical transient process; cylinder head temperature calculation S4, which is based on the linear heat distribution assumption that the ratio of the difference between the cylinder head temperature and the coolant temperature to the exhaust temperature is constant under all engine operating conditions, and calculating the cylinder head temperature at the current moment; and output and application S5, outputting the real-time cylinder head temperature for engine thermal management control.
[0032] In some implementations, the engine speed n, torque Md, and outlet water temperature Tw can be read directly from various sensors on the engine. Generally, the exhaust temperature Tp and exhaust flow rate m are not usually measured by sensors. However, the exhaust temperature Tp and exhaust flow rate m can be retrieved from the engine universal curve MAP generated after the universal characteristic test is completed on the engine bench. The steady-state exhaust temperature and exhaust flow rate are included under different speeds and torques. The corresponding steady-state exhaust temperature and exhaust flow rate are calculated by interpolation using the real-time engine speed and torque read.
[0033] In some implementations, the cylinder head temperature response exhibits thermal inertia. To convert the steady-state exhaust temperature into a transient value that matches the actual rate of metal temperature change, the dynamic thermal inertia time constant needs to be considered. The calculation formula is as follows:
[0034] (1)
[0035] in, The thermal inertia time constant under rated operating conditions can be calibrated and confirmed using a test bench. The exhaust flow rate at the rated operating point can be obtained through bench testing. The exhaust flow rate at the current operating point is obtained by interpolation on the universal curve; K is the structural thermal resistance coefficient.
[0036] In some implementations, it can be seen from formula (1) that if = ,but = ;when < At that time, thermal inertia time constant An increase indicates a slower temperature response; conversely, a decrease indicates a decrease.
[0037] In some implementations, the formula for calculating the structural thermal resistance coefficient in formula (1) is as follows:
[0038] (2)
[0039] in, The highest exhaust temperature, This is the highest temperature of the cylinder head. The highest water temperature can be obtained through bench testing.
[0040] In some implementations, the steady-state exhaust temperature obtained by interpolation calculation in step S1 is... By performing a first-order inertial delay correction, an instantaneous exhaust temperature that better reflects the physical transient process is obtained. Its discrete recursive formula is:
[0041] (3)
[0042] in, The exhaust temperature at the current moment. The exhaust temperature at the previous moment. The steady-state exhaust temperature is calculated using MAP interpolation, where Δt is the sampling period or calculation step size. The dynamic thermal inertia time constant calculated by formula (1) is Δt = 1 s. During the initialization of the calculation, It can be set to the value obtained from the current interpolation. .
[0043] In some implementations, based on the linear heat distribution assumption, the difference between cylinder head temperature and coolant temperature is calculated under all engine operating conditions. ) and exhaust temperature ( The ratio of ) is constant, that is Then the cylinder head temperature at the current moment can be calculated using the following formula:
[0044] (4)
[0045] in, The current cylinder head temperature. This is the highest temperature of the cylinder head. The highest water temperature, The highest exhaust temperature, The exhaust temperature at the current moment. The water temperature at the current moment.
[0046] In some implementations, the real-time cylinder head temperature is output for engine thermal management control, which includes controlling the operating strategies of the cooling system's electronic water pump, thermostat, and fan to achieve precise cooling; or for monitoring thermal load and triggering engine torque reduction protection; or for performing thermal fatigue damage calculations, life prediction, and improving engine reliability.
[0047] In some implementation methods, specific calculation examples are as follows:
[0048] 1. Signal Acquisition and Preprocessing. The engine's current speed n=1500 r / min, torque Md=1250 Nm, and outlet water temperature Tw=95℃ are read. Steady-state exhaust temperature is obtained by interpolation on the universal curve. =710℃, exhaust flow rate =1050kg / h.
[0049] 2. Calculation of dynamic thermal inertia time constant. Assumptions =760℃, =350℃, =105℃, then the structural thermal resistance coefficient K =1.67 is calculated according to formula (2).
[0050] Then calculate the dynamic thermal inertia time constant according to formula (1). Assuming the thermal inertia time constant calibrated at the rated point. =30, exhaust flow rate =1200kg / h, calculated according to formula (1) =31.47.
[0051] 3. Instantaneous exhaust temperature calculation. Assume the instantaneous exhaust temperature at the previous moment... =660℃, then the transient exhaust temperature at the current moment can be calculated according to formula (3). =661.56, which reflects the slow approach from 660℃ to 710℃ (steady-state value), and demonstrates the effect of thermal inertia correction very well.
[0052] 4. Cylinder head temperature calculation. The cylinder head temperature at the current moment is calculated according to formula (4). =308.27℃.
[0053] In summary, the virtual-real fusion method for sensing engine cylinder head temperature of the present invention has the following advantages: The present invention creatively proposes a real-time estimation method for engine cylinder head temperature that integrates steady-state data, dynamic physical models, and inherent structural characteristics. Its core lies in achieving rapid, accurate, and low-cost "virtual-real fusion" sensing of cylinder head metal temperature without a direct cylinder head temperature sensor through transformation and correction. The present invention utilizes experimental data covering all operating conditions and ensures the accuracy of transient processes through a physical model, making it more robust to extrapolation than a purely data-driven model.
[0054] 1. A thermal inertia time constant that dynamically changes with exhaust flow rate was proposed and defined, which accurately characterizes the transient delay characteristics in the process of exhaust temperature transfer to the cylinder head.
[0055] 2. An indirect calculation model for cylinder head temperature based on the linear heat distribution assumption is established. This model bypasses complex three-dimensional heat conduction calculations, transforming the difficult-to-measure cylinder head metal temperature into a function of easily obtainable coolant temperature and a modified exhaust temperature. The formula is simple in form, requires minimal calibration, is highly practical for engineering applications, and has a very low computational load, making it ideal for real-time operation in vehicle electronic control units (ECUs).
[0056] 3. A three-level fusion sensing architecture of "steady-state data + dynamic correction + structural characteristics" is established, systematically integrating the above-mentioned inventions into a complete sensing process, achieving deep fusion of data and models. The first level, the data layer, utilizes the engine steady-state universal characteristic MAP (database) obtained from pre-experimentation to interpolate basic steady-state exhaust parameters based on real-time speed / torque. The second level, the dynamic correction layer, uses a dynamic thermal inertia time constant model to perform first-order inertial delay correction on the steady-state exhaust temperature, obtaining a "virtual" transient exhaust temperature that reflects the actual thermal inertia process. The third level, the physical conversion layer, uses a linear heat distribution model combined with the current coolant temperature ("real" sensor signal) to convert the corrected exhaust-side temperature, ultimately achieving low-cost indirect calculation of the final target, thus completely solving the technical challenge of "real-time cylinder head temperature sensing."
[0057] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.
Claims
1. A method for sensing engine cylinder head temperature using a virtual-real fusion approach, characterized in that, include: Signal acquisition and preprocessing includes real-time acquisition of various operating parameters of the engine, including engine speed, torque, outlet water temperature, exhaust temperature and exhaust flow rate, and calculation of the steady-state exhaust temperature and exhaust flow rate corresponding to the real-time engine speed and torque using the operating parameters; The calculation of the dynamic thermal inertia time constant includes converting the steady-state exhaust temperature into a transient value that matches the actual metal temperature change rate based on the thermal inertia of the cylinder head temperature response, and calculating the dynamic thermal inertia time constant. Instantaneous exhaust temperature calculation: The calculated steady-state exhaust temperature is corrected by a first-order inertial delay to obtain the instantaneous exhaust temperature that conforms to the physical transient process. Cylinder head temperature calculation is based on the linear heat distribution assumption, which states that the ratio of the difference between cylinder head temperature and coolant temperature to exhaust temperature remains constant under all engine operating conditions. The calculation determines the cylinder head temperature at the current moment. Output and application: Outputs real-time cylinder head temperature for engine thermal management control.
2. The method for sensing engine cylinder head temperature by integrating virtual and real data as described in claim 1, characterized in that, The speed, torque, and outlet water temperature can be directly read from various sensors of the engine. The exhaust temperature and exhaust flow rate can be obtained from the engine universal curve generated after the universal characteristic test is completed on the engine bench. The steady-state exhaust temperature and exhaust flow rate include different speeds and torques. The corresponding steady-state exhaust temperature and exhaust flow rate are calculated by interpolation using the real-time engine speed and torque read.
3. The method for sensing engine cylinder head temperature by integrating virtual and real data as described in claim 2, characterized in that, The formula for calculating the dynamic thermal inertia time constant is as follows: （1） in, The thermal inertia time constant under rated operating conditions can be calibrated and confirmed using a test bench. The exhaust flow rate at the rated operating point can be obtained through bench testing. The exhaust flow rate at the current operating point is obtained by interpolation on the universal curve; K is the structural thermal resistance coefficient.
4. The method for sensing engine cylinder head temperature by integrating virtual and real data as described in claim 3, characterized in that, From formula (1), we can see that if = ,but = ;when < At that time, thermal inertia time constant An increase indicates a slower temperature response; conversely, a decrease indicates a decrease.
5. The method for sensing engine cylinder head temperature by integrating virtual and real data as described in claim 3, characterized in that, The formula for calculating the structural thermal resistance coefficient in formula (1) is as follows: （2） in, The highest exhaust temperature, This is the highest temperature of the cylinder head. The highest water temperature can be obtained through bench testing.
6. The method for sensing engine cylinder head temperature by integrating virtual and real data as described in claim 3, characterized in that, The discrete recursive formula for the exhaust temperature at the current moment is: （3） in, The exhaust temperature at the current moment. The exhaust temperature at the previous moment. The steady-state exhaust temperature is calculated using MAP interpolation, where Δt is the sampling period or calculation step size. The dynamic thermal inertia time constant calculated by formula (1) is Δt = 1 s. During the initialization of the calculation, It can be set to the value obtained from the current interpolation. .
7. The method for sensing engine cylinder head temperature by integrating virtual and real data as described in claim 3, characterized in that, Based on the linear heat distribution assumption, under all engine operating conditions, the difference between cylinder head temperature and coolant temperature ( ) and exhaust temperature ( The ratio of ) is constant, that is Then the cylinder head temperature at the current moment can be calculated using the following formula: （4） in, The current cylinder head temperature. This is the highest temperature of the cylinder head. The highest water temperature, The highest exhaust temperature, The exhaust temperature at the current moment. The water temperature at the current moment.
8. The method for sensing engine cylinder head temperature by integrating virtual and real data as described in claim 3, characterized in that, The engine outputs real-time cylinder head temperature for engine thermal management control, which includes controlling the operation strategy of the cooling system's electronic water pump, thermostat, and fan to achieve precise cooling; or monitoring thermal load to trigger engine torque reduction protection; or performing thermal fatigue damage calculations to predict engine life and improve engine reliability.