Method for evaluating engine ultra-low temperature cold start warm-up time

Abstract

The application discloses an evaluation method for engine ultra-low temperature cold start warm-up time, comprising the following steps: S100, establishing an engine thermodynamic physical submodel; S200, establishing an engine cooling system submodel; S300, establishing an engine lubrication system submodel; S400, establishing an engine thermal network system submodel; S500, integrating multiple submodels to establish an engine thermal management model; S600, calibrating the thermal management model; S700, simulating an engine start-up and warm-up process based on the engine thermal management model; and S800, obtaining a warm-up time according to the engine start-up and warm-up process. The application can save the cost of hot start test, provide a more accurate thermal management model, and save the test cost by replacing the test resource occupation with the simulated warm-up time.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of engine cold start, in particular to an evaluation method of engine ultra-low temperature cold start warm-up time. BACKGROUND

[0002] In some existing ultra-low temperature cold start sub-market, the engine coolant temperature is required to rise to a specified temperature (preferably 40 DEG C) within a specified time, and the cab heater and the like can be started only when the temperature condition is reached. In order to achieve the corresponding target, warm-up tests at different idle speeds are required, which not only has high cost, but also has long cycle. Usually, the engine (or vehicle) is placed in a cold storage before the test to be fully cooled until the specified low temperature condition is reached, and then the start test can be carried out. In the case of tight cold storage resources, too many warm-up tests of working conditions cannot be carried out. Therefore, the existing method for evaluating the cold start warm-up time in the field has the main problems of high cost and tight test resources.

[0003] The information disclosed in this BACKGROUND section is only for the purpose of increasing the understanding of the background of the present application and should not be taken as an acknowledgment or any form of suggestion that this information forms prior art that is publicly known. SUMMARY

[0004] The present application aims to provide an evaluation method of engine ultra-low temperature cold start warm-up time, which can solve the problems in the background art.

[0005] To achieve the above-mentioned purpose, the present application provides an evaluation method of engine ultra-low temperature cold start warm-up time, based on an evaluation model of engine ultra-low temperature cold start warm-up time, characterized in that it comprises the following steps: S100: establishing an engine thermodynamic physical submodel; S200: establishing an engine cooling system submodel; S300: establishing an engine lubrication system submodel; S400: establishing an engine thermal network system submodel; S500: integrating a plurality of submodels 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 comprises: S110, acquiring universal characteristic data of the engine; S120, acquiring target calibration data based on the universal characteristic data; S130, calibrating modules of the engine thermodynamic physical sub-model based on the target calibration data; wherein the target calibration data comprises intake air flow, temperature of each part, pressure of each part, and engine oil consumption; and the modules of the engine thermodynamic physical sub-model comprise: air filter, intake pipe, supercharger, intercooler, intake manifold, intake port, combustion chamber, exhaust port, exhaust manifold, exhaust pipe, and aftertreatment system.

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

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

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

[0010] In one or more embodiments, the step S500 comprises: S510, merging the engine thermodynamic physical 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, establishing energy flow relationship and temperature sensing relationship between each sub-model of the engine thermal management model.

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

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

[0013] The second aspect of the present application provides an evaluation model of the engine ultra-low temperature cold start warm-up time, which is used to implement the evaluation method of the engine ultra-low temperature cold start warm-up time according to any one of claims 1-8, and is characterized in that the evaluation model of the engine ultra-low temperature cold start warm-up time comprises the engine thermal management model; the engine thermal management model comprises: an engine thermodynamic physical 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 application at least have the following technical effects or advantages:

[0015] By first establishing a cold start model of each component of the engine to form an overall engine thermal management model, the cost of hot start test is saved; by running the engine thermal management model under simulated external characteristic working conditions to obtain warm-up time results, and comparing with the actual engine warm-up time test results obtained by cold storage test, the thermal management model is corrected to be more accurate; by correcting the thermal management model with a small amount of test resources, subsequent warm-up time results can be obtained by simulation test, instead of subsequent test resource occupation, thereby saving test cost. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which are included to provide a further understanding of the application and constitute a part of this application, illustrate embodiments of the application and together with the description serve to explain the application. Embodiments of the application illustrated in the drawings and their descriptions are to be considered in all respects as illustrative and not restrictive of the application. In the drawings:

[0017] Figure 1 A whole flowchart of an evaluation method of an engine ultra-low temperature cold start warm-up time provided by the application is shown in the figure.

[0018] Figure 2 A specific flowchart of steps S600, S700 and S800 of an evaluation method of an engine ultra-low temperature cold start warm-up time provided by the application is shown in the figure. DETAILED DESCRIPTION

[0019] Unless otherwise defined, the terms "comprises", "comprising", "includes", "including", "consists", "consisting", "is" or "are" or "consisting of" as used throughout the specification and claims, shall be construed as including the stated elements or components, but not excluding other elements or components.

[0020] The application aims to provide an evaluation method of an engine ultra-low temperature cold start warm-up time, which can reduce the test cost of engine cold start time and avoid the shortage of cold storage environment test scene.

[0021] Embodiment one:

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

[0023] Specifically, in order to reduce the cold start time test cost, the application provides an evaluation method for engine ultra-low temperature cold start warm-up time, which establishes a cold start model of each component of the engine first to form an overall engine thermal management model, the thermal management model is used to simulate the heat transfer characteristics of the engine according to different engine models, and a plurality of thermal management models can be obtained by inputting a plurality of engine data for testing, so that the thermal start test cost can be saved; further, the engine thermal management model is run under the simulated external characteristic condition to obtain the warm-up time result, and the actual engine warm-up time test result obtained by using the cold storage test is compared to correct the thermal management model to make it more accurate and close to the actual value. The embodiment only needs a small amount of test resources to correct the thermal management model, and the warm-up time result can be obtained by simulation test in the subsequent, instead of occupying the subsequent test resources, thereby saving the test cost. The simulation speed of the method is high, and the model running time is shorter than the actual vehicle running time, so that the prediction of different idle conditions can be carried out in a short period. The method provides a low-cost and high-precision analysis means for selecting and optimizing a reliable, effective and energy-saving cold start scheme under ultra-low temperature conditions.

[0024] As a preferred embodiment of the present embodiment, the step S100 comprises: S110: obtaining the universal characteristic data of the engine; S120: obtaining target calibration data based on the universal characteristic data; S130: calibrating the modules of the engine thermodynamic physical sub-model based on the target calibration data; wherein the target calibration data comprises intake air flow, temperature of each part, pressure of each part, and engine fuel consumption; and the modules of the engine thermodynamic physical sub-model comprise: air filter, intake pipe, supercharger, intercooler, intake manifold, intake port, combustion chamber, exhaust port, exhaust manifold, exhaust pipe and aftertreatment system.

[0025] Specifically, in order to provide the initial calibration of the engine thermodynamic physical sub-model, the universal characteristics of the engine are obtained by table lookup, the engine thermodynamic physical sub-model conforming to the actual thermodynamic characteristics of the engine is established, the evaluation model for engine ultra-low temperature cold start warm-up time obtains the calibration data of the air filter, intake pipe, supercharger, intercooler, intake manifold, intake port, combustion chamber, exhaust port, exhaust manifold, exhaust pipe and aftertreatment system in the engine characteristics, and restores to the modules of the engine thermodynamic physical sub-model, so as to obtain a more accurate model.

[0026] As a preferred embodiment of the present embodiment, the step S200 comprises: S210: obtaining engine cooling function test data; S220: calibrating the modules of the engine cooling system sub-model based on the engine cooling function test data; wherein the engine cooling function test data comprises branch flow, temperature rise, pressure difference; and the modules of the engine cooling system sub-model comprise water pump, engine block cylinder head water jacket, thermostat, radiator, and oil cooler.

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

[0028] As a preferred embodiment of the present embodiment, the step S300 comprises: S310: obtaining engine lubrication function test data; S320: calibrating the modules of the engine lubrication system sub-model based on the engine lubrication function test data; wherein the engine lubrication function test data comprises oil pressure of each part and oil temperature; and the modules of the engine lubrication system sub-model comprise oil pump, oil cooler, oil filter, main bearing, connecting rod bearing, piston cooling jet, and oil cooler.

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

[0030] As a preferred embodiment of the present embodiment, the step S400 comprises: S410: obtaining engine heat transfer characteristic experimental data; S420: setting mass and specific heat of the mass blocks in the engine thermal network system sub-model based on the engine heat transfer characteristic experimental data; S430: establishing heat transfer connection between the mass blocks in the engine thermal network system sub-model based on the engine heat transfer characteristic experimental data; wherein the modules in the engine thermal network system sub-model comprise engine block, cylinder head, cylinder liner, piston, connecting rod, crankshaft, intake pipe, exhaust pipe, and supercharger; and the mass blocks are formed by subdividing the modules in the engine thermal network system sub-model based on temperature-sensitive characteristics, and the modules with similar temperature-sensitive characteristics.

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

[0032] As a preferred embodiment of the present embodiment, the step S500 comprises: S510: merging the engine thermodynamic physical 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 various sub-models of the engine thermal management model.

[0033] Specifically, in order to integrate multiple sub-models to form a whole with unified deployment attributes, the present 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 of source levels and modules, the connection of signal transmission and additional sensing circuits, the probes of the sensing circuits are connected to the engine for transmitting cold start warm-up data. The thermal management model assembly capable of simulating the engine starting process and transmitting the engine warm-up time is comprehensively formed.

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

[0035] Specifically, in order to fit the thermal start-up data obtained by the evaluation method of the engine ultra-low temperature cold start warm-up time, the present embodiment provides a method for eliminating error loss by training the evaluation method of the engine ultra-low temperature cold start warm-up time multiple times, so that the method simulates a more realistic warm-up time. Wherein, the "adjusting the heat exchange 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 to constantly reduce the loss to obtain the most realistic heat exchange coefficients, adjusting the heat exchange coefficients according to the experience of professional technicians, finding more accurate heat exchange coefficients by multiple value taking, etc.

[0036] As a preferred embodiment of the present embodiment, the step S700 comprises: S710: placing the evaluation model of the engine ultra-low temperature cold start warm-up time under steady-state external characteristic working conditions again, if the evaluation model of the engine ultra-low temperature cold start warm-up time outputs "OK", then executing step S800; if the evaluation model of the engine ultra-low temperature cold start warm-up time outputs "NOT OK", then re-executing step S600.

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

[0038] Embodiment two:

[0039] The embodiment provides an engine ultra-low temperature cold start warm-up time evaluation model, based on the same concept, the engine ultra-low temperature cold start warm-up time evaluation model is used to realize the engine ultra-low temperature cold start warm-up time evaluation method;

[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 comprises an engine thermodynamic physical 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 application is for purposes of illustration and example. These descriptions are not intended to limit the application to the precise form described, and obviously many changes and modifications can be suggested to one skilled in the art without departing from the spirit and scope of the application. The exemplary embodiments were chosen and described in order to explain the principles of the application and its practical application and to enable others skilled in the art to understand the application for various exemplary embodiments and various modifications as are suited to the particular use contemplated. It is intended that the scope of the application be defined by the claims and their equivalents.

Claims

1. A method for evaluating the engine's cold start warm-up time at extremely low temperatures, based on an evaluation model for the engine's cold start warm-up time at extremely low temperatures, characterized in that... Includes the following steps: S100: Establish the engine thermodynamic physical sub-model; S200: Establish a sub-model of the engine cooling system; S300: Establish a sub-model of the engine lubrication system; S400: Establish a sub-model of the engine thermal network system; S500: Integrates multiple sub-models to establish an engine thermal management model; S600: Calibrate the thermal management model; S700: Based on the aforementioned engine thermal management model, simulates the engine start-up and warm-up process; S800: Obtain the warm-up time based on the engine start-up and warm-up process; Step S500 includes: S510: Combine the engine thermodynamic physical sub-model, engine cooling system sub-model, engine lubrication system sub-model and 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 various sub-models of the engine thermal management model; Step S600 includes: S610: Place the evaluation model of the engine's ultra-low temperature cold start warm-up time under steady-state external characteristic conditions, and adjust 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 conditions are consistent with the experimental values. S620: Perform transient warm-up calibration, adjust the heat transfer coefficient between the heat network and the cooling and lubrication system, so that the calculated results under the corresponding operating conditions are consistent with the test values.

2. The method for evaluating the engine's cold start warm-up time at extremely low temperatures as described in claim 1, characterized in that, Step S100 includes: S110: Obtain the universal characteristic data of the engine; S120: Based on the universal characteristic data, obtain the target calibration data; S130: A module for calibrating the engine thermodynamic physical sub-model based on target calibration data; The target calibration data includes intake air flow, temperature of various parts, pressure of various parts, and engine fuel consumption; the modules of the engine thermodynamic physical sub-model include: air filter, intake manifold, turbocharger, intercooler, intake manifold, intake duct, combustion chamber, exhaust duct, exhaust manifold, exhaust manifold, and aftertreatment system.

3. The method for evaluating the engine's cold start warm-up time at extremely low temperatures as described in claim 1, characterized in that, Step S200 includes: S210: Obtain test data on engine cooling function; S220: A module for calibrating the sub-model of the engine cooling system based on the engine cooling function test data; 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 water pump, cylinder head water jacket, thermostat, radiator, and oil cooler.

4. The method for evaluating the engine's cold start warm-up time at extremely low temperatures as described in claim 3, characterized in that, Step S300 includes: S310: Obtain test data on engine lubrication function; S320: A module for calibrating the engine lubrication system sub-model based on the engine lubrication function test data; The engine lubrication function test data includes oil pressure and oil temperature at various locations; the engine lubrication system sub-model modules include oil pump, oil cooler, oil filter, main bearing, connecting rod bearing, piston cooling spray, and oil cooler.

5. The method for evaluating the engine's cold start warm-up time at extremely low temperatures as described in claim 4, characterized in that, Step S400 includes: S410: Acquire experimental data on engine heat transfer characteristics; S420: Based on the experimental data of the engine heat transfer characteristics, set the mass and specific heat of the mass block in the engine thermal network system sub-model; S430: Based on the experimental data of the engine heat transfer characteristics, establish the heat transfer connection between the mass blocks in the engine thermal network system sub-model; The modules in the engine thermal network system sub-model include: engine block, cylinder head, cylinder liner, piston, connecting rod, crankshaft, intake manifold, exhaust manifold, and turbocharger; the mass block is formed by subdividing the modules in the engine thermal network system sub-model based on temperature-sensitive characteristics, and the modules with similar temperature-sensitive characteristics are subdivided.

6. The method for evaluating the engine's cold start warm-up time at extremely low temperatures as described in claim 5, characterized in that, Step S700 includes: S710: Place the evaluation model for the engine's ultra-low temperature cold start warm-up time back under steady-state external characteristic conditions. If the evaluation model for the engine's ultra-low temperature cold start warm-up time outputs "OK", then execute step S800; if the evaluation model for the engine's ultra-low temperature cold start warm-up time outputs "NOT OK", then execute step S600 again.

7. An evaluation model for engine cold start warm-up time at extremely low temperatures, wherein the evaluation model is used to implement the evaluation method for engine cold start warm-up time at extremely low temperatures as described in any one of claims 1-6, characterized in that, The evaluation model for engine cold start warm-up time at ultra-low temperatures includes the engine thermal management model; the engine thermal management model includes: an engine thermodynamic physical 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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