Evaluation method for ultralow-temperature cold start warm-up time of engine

Abstract

The invention discloses a method for evaluating the warm-up time of ultralow-temperature cold start of an engine. The method comprises the following steps: S100, establishing a thermodynamic physical sub-model of the engine; s200, establishing an engine cooling system sub-model; s300, establishing a sub-model of the engine lubrication system; s400, establishing an engine heat network system sub-model; s500, integrating a plurality of sub-models, and establishing an engine thermal management model; s600, carrying out calibration on the thermal management model; s700, on the basis of the engine heat management model, the engine starting and warming process is simulated; and S800, according to the engine warming-up starting process, the warming-up time is obtained. According to the invention, the hot start test cost can be saved; a more accurate thermal management model is provided; and the test resource occupation is replaced by simulating the engine heating time, so that the test cost is saved.

Description

Technical Field

[0001] The invention relates to the field of engine cold starting, and in particular to a method for evaluating the warm-up time of an engine during ultra-low temperature cold starting. Background Art

[0002] In some existing ultra-low temperature cold start market segments, the engine coolant temperature is required to rise to a specified temperature (preferably 40°C) within a specified time. Only when this temperature condition is reached can the cab heater be turned on. In order to achieve the corresponding goals, warm-up tests at different no-load speeds are required, which is not only costly but also time-consuming. Usually, before the test, the engine (or the entire vehicle) must be placed in a cold storage for sufficient cooling until it reaches the specified low temperature condition. Only then can the start-up test be carried out. In the case of tight cold storage resources, it is not possible to carry out too many warm-up tests under working conditions. Therefore, the main problems with the existing methods for field evaluation of cold start warm-up time are: high cost and tight test resources.

[0003] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0004] The present invention aims to provide a method for evaluating the ultra-low temperature cold start warm-up time of an engine, which can solve the problems existing in the background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides an evaluation method for the ultra-low temperature cold start warm-up time of an engine, which is based on an evaluation model for the ultra-low temperature cold start warm-up time of an engine, and is characterized in that it includes the following steps: S100: establishing an engine thermodynamic physics sub-model; S200: establishing an engine cooling system sub-model; S300: establishing an engine lubrication system sub-model; S400: establishing an engine thermal network system sub-model; S500: integrating multiple sub-models to establish an engine thermal management model; S600: calibrating the thermal management model; S700: simulating the engine start-up warm-up process based on the engine thermal management model; S800: obtaining the warm-up time according to the engine start-up warm-up process.

[0006] In one or more embodiments, the step S100 includes: S110: obtaining universal characteristic data of the engine; S120: obtaining target calibration data based on the universal characteristic data; S130: calibrating the module of the engine thermodynamic physics sub-model based on the target calibration data; wherein the target calibration data includes intake flow, temperature of each part, pressure of each part, and engine fuel consumption; the module of the engine thermodynamic physics sub-model includes: air filter, intake pipe, supercharger, intercooler, intake manifold, intake duct, combustion chamber, exhaust duct, exhaust manifold, exhaust pipe and after-treatment system.

[0007] In one or more embodiments, the step S200 includes: S210: acquiring engine cooling function test data; S220: calibrating the module of the engine cooling system sub-model based on the engine cooling function test data; wherein the engine cooling function test data includes the flow rate, temperature rise, and pressure difference of each branch; the module of the engine cooling system sub-model includes a water pump, a cylinder head water jacket, a thermostat, a radiator, and an oil cooler.

[0008] In one or more embodiments, the step S300 includes: S310: acquiring engine lubrication function test data; S320: calibrating the module of the engine lubrication system sub-model based on the engine lubrication function test data; wherein, the engine lubrication function test data includes the oil pressure and oil temperature of each part; the module of the engine lubrication system sub-model includes an oil pump, an oil cooler, an oil filter, a main bearing, a connecting rod bearing, a piston cooling spray hook, and an oil cooler.

[0009] In one or more embodiments, the step S400 includes: S410: obtaining experimental data on engine heat transfer characteristics; S420: setting the mass and specific heat of the mass block in the engine thermal network system sub-model based on the experimental data on engine heat transfer characteristics; S430: establishing a heat transfer connection between mass blocks in the engine thermal network system sub-model based on the experimental data on engine heat transfer characteristics; wherein the modules in the engine thermal network system sub-model include: engine body, cylinder head, cylinder liner, piston, connecting rod, crankshaft, intake pipe, exhaust pipe, supercharger; the mass block is a module in the engine thermal network system sub-model that is formed by subdividing the modules based on temperature-sensitive characteristics, and has similar temperature-sensitive characteristics.

[0010] In one or more embodiments, the step S500 includes: S510: merging the engine thermodynamic physics sub-model, the engine cooling system sub-model, the engine lubrication system sub-model and the engine thermal network system sub-model to form an engine thermal management model; S520: constructing the energy flow relationship and temperature sensing relationship between the sub-models of the engine thermal management model.

[0011] In one or more embodiments, the step S600 includes: S610: placing the evaluation model of the engine ultra-low temperature cold start warm-up time under a steady-state external characteristic condition, adjusting the heat transfer coefficients between the engine thermal network system submodel, the engine cooling system submodel, and the engine lubrication system submodel, so that the calculation results under the corresponding conditions are consistent with the test values. S620: performing transient warm-up calibration, adjusting the heat transfer coefficients between the thermal network and the cooling and lubrication system, so that the calculation results under the corresponding conditions are consistent with the test values.

[0012] In one or more embodiments, the step S700 includes: S710: placing the evaluation model of the engine ultra-low temperature cold start warm-up time under a steady-state external characteristic condition again. If the evaluation model of the engine ultra-low temperature cold start warm-up time outputs "OK", step S800 is executed; if the evaluation model of the engine ultra-low temperature cold start warm-up time outputs "NOT OK", step S600 is re-executed.

[0013] In a second aspect, the present invention provides an evaluation model for an engine's ultra-low temperature cold start warm-up time, wherein the evaluation model for an engine's ultra-low temperature cold start warm-up time is used to implement an engine's ultra-low temperature cold start warm-up time evaluation method as described in any one of claims 1 to 8, and is characterized in that the evaluation model for an engine's ultra-low temperature cold start warm-up time includes the engine thermal management model; the engine thermal management model includes: an engine thermodynamics physics sub-model, an engine cooling system sub-model, an engine lubrication system sub-model and an engine thermal network system sub-model.

[0014] Compared with the prior art, the multiple technical solutions and embodiments provided by the present invention have at least the following technical effects or advantages:

[0015] By first establishing cold start models for each engine component, an overall engine thermal management model is formed, thereby saving hot start test costs; by running the engine thermal management model under simulated external characteristic conditions to obtain warm-up time results, and using the actual engine warm-up time test results of cold storage tests for comparison, the thermal management model is corrected to make it more accurate; by correcting the thermal management model with a small amount of test resources, the warm-up time results can be obtained through subsequent simulation tests, replacing subsequent test resource occupation and saving test costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and can be considered as illustrative of various combinations of preferred embodiments and do not constitute an improper limitation on the present invention. In the drawings:

[0017] Figure 1 A schematic diagram of the overall process of a method for evaluating the ultra-low temperature cold start warm-up time of an engine provided by the present invention;

[0018] Figure 2 A schematic diagram of a specific flow chart of steps S600, S700 and S800 of a method for evaluating an engine ultra-low temperature cold start warm-up time provided by the present invention. DETAILED DESCRIPTION

[0019] Unless explicitly stated otherwise, throughout the specification and claims, the term "comprise" or its variations such as "include" or "comprising", "made of", etc. will be understood to include the stated elements or components but not to exclude other elements or other components.

[0020] The purpose of the present invention is to provide an evaluation method for the ultra-low temperature cold start warm-up time of an engine, so as to reduce the cost of testing the cold start time of the engine and avoid the tense test scene of the cold storage environment.

[0021] Embodiment 1:

[0022] The present embodiment provides an evaluation method for the ultra-low temperature cold start warm-up time of an engine, which is based on an evaluation model for the ultra-low temperature cold start warm-up time of an engine, and is characterized in that it includes the following steps: S100: establishing an engine thermodynamic physics sub-model; S200: establishing an engine cooling system sub-model; S300: establishing an engine lubrication system sub-model; S400: establishing an engine thermal network system sub-model; S500: integrating multiple sub-models to establish an engine thermal management model; S600: calibrating the thermal management model; S700: simulating the engine start-up warm-up process based on the engine thermal management model; S800: obtaining the warm-up time according to the engine start-up warm-up process.

[0023] Specifically, in order to reduce the cost of cold start time testing, the present invention provides an evaluation method for the ultra-low temperature cold start warm-up time of an engine. By first establishing cold start models of various engine components, an overall engine thermal management model is formed. The thermal management model is used to simulate the heat transfer characteristics of the engine according to different engine models. By inputting a variety of engine data, a variety of thermal management models can be obtained for testing, thereby saving the cost of hot start testing; further, the engine thermal management model is operated under simulated external characteristic conditions to obtain the warm-up time result, and by comparing the actual engine warm-up time test results of the cold storage test, the thermal management model is corrected to make it more accurate and close to the actual value. This embodiment only requires a small amount of test resources to correct the thermal management model, and the warm-up time results can be obtained through simulation tests in the future, replacing the subsequent test resource occupation, saving the test cost. The simulation speed of this method is high, and the model running time is shorter than the actual vehicle operation time, and different idle conditions can be predicted in a short time. The establishment of this method provides a low-cost and high-precision analysis means for the selection and optimization of reliable, effective and energy-saving cold start schemes under ultra-low temperature conditions.

[0024] As a preferred implementation manner of this embodiment, the step S100 includes: S110: obtaining universal characteristic data of the engine; S120: obtaining target calibration data based on the universal characteristic data; S130: calibrating the module of the engine thermodynamic physics sub-model based on the target calibration data; wherein the target calibration data includes intake flow, temperature of each part, pressure of each part, and engine fuel consumption; the module of the engine thermodynamic physics sub-model includes: air filter, intake pipe, supercharger, intercooler, intake manifold, intake duct, combustion chamber, exhaust duct, exhaust manifold, exhaust pipe and after-treatment system.

[0025] Specifically, in order to provide an initial calibration of the engine thermodynamic physics sub-model, the universal characteristics of the engine are obtained by looking up a table, and an engine thermodynamic physics sub-model that conforms to the actual thermodynamic characteristics of the engine is established. The evaluation model of the ultra-low temperature cold start warm-up time of the engine obtains the calibration data of the air filter, intake pipe, supercharger, intercooler, intake manifold, intake duct, combustion chamber, exhaust duct, exhaust manifold, exhaust pipe and after-treatment system in the engine characteristics, and restores it to the module of the engine thermodynamic physics sub-model, so as to obtain a more accurate model.

[0026] As a preferred implementation manner of this embodiment, the step S200 includes: S210: acquiring engine cooling function test data; S220: calibrating the module of the engine cooling system sub-model based on the engine cooling function test data; wherein, the engine cooling function test data includes the flow rate, temperature rise, and pressure difference of each branch; the module of the engine cooling system sub-model includes a water pump, a cylinder head water jacket, a thermostat, a radiator, and an oil cooler.

[0027] Specifically, in order to provide initial calibration of the module of the engine cooling system sub-model, the evaluation model of the engine ultra-low temperature cold start warm-up time obtains the cooling function test data during the engine factory test and establishes an engine cooling system sub-model that conforms to the engine cooling characteristics.

[0028] As a preferred implementation manner of this embodiment, the step S300 includes: S310: acquiring engine lubrication function test data; S320: calibrating the module of the engine lubrication system sub-model based on the engine lubrication function test data; wherein, the engine lubrication function test data includes the oil pressure and oil temperature of each part; the module of the engine lubrication system sub-model includes an oil pump, an oil cooler, an oil filter, a main bearing, a connecting rod bearing, a piston cooling spray hook, and an oil cooler.

[0029] Specifically, in order to provide initial calibration of the engine lubrication system sub-model, the evaluation model of the engine ultra-low temperature cold start warm-up time obtains the engine lubrication function test data, simulates the engine oil pressure and oil temperature, and establishes an engine lubrication system sub-model that conforms to the engine cooling characteristics.

[0030] As a preferred implementation manner of this embodiment, the step S400 includes: S410: obtaining experimental data on engine heat transfer characteristics; S420: setting the mass and specific heat of the mass block in the engine thermal network system sub-model based on the experimental data on engine heat transfer characteristics; S430: establishing a heat transfer connection between the mass blocks in the engine thermal network system sub-model based on the experimental data on engine heat transfer characteristics; wherein the modules in the engine thermal network system sub-model include: engine body, cylinder head, cylinder liner, piston, connecting rod, crankshaft, intake pipe, exhaust pipe, supercharger; the mass block is a module in the engine thermal network system sub-model that is formed by subdividing the modules based on temperature-sensitive characteristics, and has similar temperature-sensitive characteristics.

[0031] Specifically, in order to provide initial calibration of the engine thermal network system sub-model, the evaluation model of the engine ultra-low temperature cold start warm-up time obtains experimental data on the engine heat transfer characteristics, simulates the mass and specific heat of each mass block of the engine, and establishes an engine thermal network system sub-model that conforms to the engine cooling characteristics.

[0032] As a preferred implementation manner of this embodiment, the step S500 includes: S510: merging the engine thermodynamic physics sub-model, the engine cooling system sub-model, the engine lubrication system sub-model and the engine thermal network system sub-model to form an engine thermal management model; S520: constructing the energy flow relationship and temperature sensing relationship between the sub-models of the engine thermal management model.

[0033] Specifically, in order to integrate multiple sub-models and form a whole with unified allocation properties, this embodiment realizes the merging of multiple sub-models by electrically connecting the electrical signals and circuits of multiple sub-models; the merging includes the connection between the source level and each module, the connection of signal transmission, and an additional sensor circuit, the probe of the sensor circuit is connected to the engine to transmit cold start warm-up data. The thermal management model assembly that can simulate the engine start-up process and transmit the engine warm-up time is formed.

[0034] As a preferred implementation of this embodiment, the step S600 includes: S610: placing the evaluation model of the engine ultra-low temperature cold start warm-up time under a steady-state external characteristic condition, adjusting the heat transfer coefficients between the engine thermal network system submodel, the engine cooling system submodel and the engine lubrication system submodel, so that the calculation results under the corresponding conditions are consistent with the test values. S620: performing transient warm-up calibration, adjusting the heat transfer coefficients between the thermal network and the cooling and lubrication system, so that the calculation results under the corresponding conditions are consistent with the test values.

[0035] Specifically, in order to fit the hot start data obtained by the method for evaluating the engine ultra-low temperature cold start warm-up time, the present embodiment provides a method for evaluating the engine ultra-low temperature cold start warm-up time by multiple training to eliminate error losses, so that the method simulates a warm-up time that is closer to the actual one. Among them, the "adjusting the heat transfer coefficients between the engine thermal network system sub-model, the engine cooling system sub-model and the engine lubrication system sub-model so that the calculation results under the corresponding working conditions are consistent with the test values" includes but is not limited to: using algorithms and continuously reducing losses to obtain the most realistic heat transfer coefficient, professional technicians adjusting the heat transfer coefficient based on experience, and finding a more accurate heat transfer coefficient through multiple value taking, etc.

[0036] As a preferred implementation manner of this embodiment, the step S700 includes: S710: placing the evaluation model of the engine ultra-low temperature cold start warm-up time under a steady-state external characteristic condition again. If the evaluation model of the engine ultra-low temperature cold start warm-up time outputs "OK", step S800 is executed; if the evaluation model of the engine ultra-low temperature cold start warm-up time outputs "NOT OK", step S600 is re-executed.

[0037] Specifically, the evaluation model of the engine ultra-low temperature cold start warm-up time can obtain the experimental data curve corresponding to the actual cold start warm-up time of the engine, and compare it with the experimental data of the cold start warm-up time obtained by the method, and determine the error amplitude between the actual warm-up time and the simulated warm-up time through mathematical calculation methods such as standard deviation. When the error amplitude is not greater than the threshold value of the negligible error, the evaluation model of the engine ultra-low temperature cold start warm-up time outputs "OK", and the method continues to execute step S800; when the error amplitude is greater than the threshold value of the negligible error, the evaluation model of the engine ultra-low temperature cold start warm-up time outputs "NOT OK", and returns to step S600 to modify the heat transfer coefficient and try again, so as to make the data more accurate. The threshold is preset into the evaluation model of the engine ultra-low temperature cold start warm-up time by professional technicians.

[0038] Embodiment 2:

[0039] This embodiment provides an evaluation model for the ultra-low temperature cold start warm-up time of an engine. Based on the same concept, the evaluation model for the ultra-low temperature cold start warm-up time of an engine is used to implement the evaluation method for the ultra-low temperature cold start warm-up time of an engine;

[0040] The engine ultra-low temperature cold start warm-up time evaluation model comprises the engine thermal management model;

[0041] The engine thermal management model includes: an engine thermodynamics physics sub-model, an engine cooling system sub-model, an engine lubrication system sub-model and an engine thermal network system sub-model.

[0042] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A method for evaluating the ultra-low temperature cold start warm-up time of an engine, based on an evaluation model for the ultra-low temperature cold start warm-up time of an engine, characterized in that: The steps include: S100: Establish the engine thermodynamic physics sub-model; S200: Establishing the engine cooling system sub-model; S300: Establishing the engine lubrication system sub-model; S400: Establish the engine thermal network system sub-model; S500: Integrate multiple sub-models to establish an engine thermal management model; S600: Calibrate the thermal management model; S700: simulating an engine startup warm-up process based on the engine thermal management model; S800: Acquire the warm-up time according to the engine startup warm-up process.

2. The method for evaluating the engine ultra-low temperature cold start warm-up time according to claim 1, characterized in that: The step S100 includes: S110: Acquiring universal characteristic data of the engine; S120: Acquire target calibration data based on the universal characteristic data; S130: Calibrate a module of the engine thermodynamics physics sub-model based on the target calibration data; Among them, the target calibration data includes intake flow, temperature of various parts, pressure of various parts, and engine fuel consumption; the modules of the engine thermodynamic physics sub-model include: air filter, intake pipe, supercharger, intercooler, intake manifold, intake duct, combustion chamber, exhaust duct, exhaust manifold, exhaust pipe and after-treatment system.

3. The method for evaluating the engine ultra-low temperature cold start warm-up time as claimed in claim 1, characterized in that: The step S200 includes: S210: Acquiring engine cooling function test data; S220: Calibrate a module of the engine cooling system sub-model based on the engine cooling function test data; Among them, the engine cooling function test data includes the flow rate, temperature rise and pressure difference of each branch; the modules of the engine cooling system sub-model include a water pump, a cylinder head water jacket, a thermostat, a radiator and an oil cooler.

4. The method for evaluating the engine ultra-low temperature cold start warm-up time as claimed in claim 3, characterized in that: The step S300 includes: S310: Acquiring engine lubrication function test data; S320: Calibrate a module of the engine lubrication system sub-model based on the engine lubrication function test data; Among them, the engine lubrication function test data includes oil pressure and oil temperature of various parts; the modules of the engine lubrication system sub-model include oil pump, oil cooler, oil filter, main bearing, connecting rod bearing, piston cooling spray hook, and oil cooler.

5. The method for evaluating the engine ultra-low temperature cold start warm-up time as claimed in claim 4, characterized in that: The step S400 includes: S410: Acquire engine heat transfer characteristic experimental data; S420: Based on the engine heat transfer characteristic experimental data, setting the mass and specific heat of the mass block in the engine thermal network system submodel; S430: establishing heat transfer connections between mass blocks in the engine thermal network system submodel based on the engine heat transfer characteristic experimental data; Among them, the modules in the engine thermal network system sub-model include: engine body, cylinder head, cylinder liner, piston, connecting rod, crankshaft, intake pipe, exhaust pipe, and supercharger; the mass block is a module with similar temperature-sensitive characteristics that is formed by subdividing the modules in the engine thermal network system sub-model based on temperature-sensitive characteristics.

6. The method for evaluating the engine ultra-low temperature cold start warm-up time as claimed in claim 4, characterized in that: The step S500 includes: S510: combining the engine thermodynamics physics sub-model, the engine cooling system sub-model, the engine lubrication system sub-model and the engine thermal network system sub-model to form an engine thermal management model; S520: Constructing energy flow relationships and temperature sensing relationships between various sub-models of the engine thermal management model.

7. The method for evaluating the engine ultra-low temperature cold start warm-up time as claimed in claim 4, characterized in that: The step S600 includes: S610: placing the evaluation model of the engine ultra-low temperature cold start warm-up time under a steady-state external characteristic condition, adjusting the heat transfer coefficients among the engine thermal network system sub-model, the engine cooling system sub-model and the engine lubrication system sub-model, so that the calculation results under the corresponding conditions are consistent with the test values. S620: Perform transient warm-up calibration and adjust the heat transfer coefficient between the thermal network and the cooling and lubrication system so that the calculated results under the corresponding working conditions are consistent with the test values.

8. The method for evaluating the engine ultra-low temperature cold start warm-up time as claimed in claim 7, characterized in that: The step S700 includes: S710: Place the evaluation model of the engine ultra-low temperature cold start warm-up time under steady-state external characteristic conditions again. If the evaluation model of the engine ultra-low temperature cold start warm-up time outputs "OK", execute step S800; if the evaluation model of the engine ultra-low temperature cold start warm-up time outputs "NOT OK", re-execute step S600.

9. An evaluation model for engine ultra-low temperature cold start warm-up time, the evaluation model for engine ultra-low temperature cold start warm-up time is used to implement an evaluation method for engine ultra-low temperature cold start warm-up time as claimed in any one of claims 1 to 8, characterized in that: The evaluation model for the engine ultra-low temperature cold start warm-up time includes the engine thermal management model; the engine thermal management model includes: an engine thermodynamic physics sub-model, an engine cooling system sub-model, an engine lubrication system sub-model and an engine thermal network system sub-model.

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