Determination method, device and equipment of waste gas mass flow, medium and vehicle

Abstract

The invention relates to an exhaust gas mass flow determination method, device and equipment, a medium and a vehicle. According to the embodiment of the invention, the air mass flow, the first relative humidity, the first pressure and the first temperature of fresh air entering the engine and the second relative humidity, the second pressure and the second temperature of mixed gas formed by mixing the fresh air and waste gas generated by combustion of the engine are obtained; calculating a first water content and a first molar weight of the fresh air based on the air mass flow, the first relative humidity, the first pressure and the first temperature; the exhaust gas flow is calculated on the basis of the second relative humidity, the second pressure, the second temperature, the first water content and the first molar weight, the actual mass flow of the exhaust gas in the mixed gas is obtained, limitation of the ratio of the front pressure to the rear pressure of an EGR valve can be avoided, the determination precision of the exhaust gas mass flow in the EGR system is improved, and the practicability is high. And the control difficulty of the exhaust gas flow in the EGR system is reduced, devices required for determining the exhaust gas mass flow are reduced, and the cost is reduced.

Description

Technical Field

[0001] The present disclosure relates to the field of internal combustion engine control technology, and in particular to a method, device, equipment, medium and vehicle for determining an exhaust gas mass flow rate. Background Art

[0002] With the gradual improvement of the requirements for fuel consumption and emissions of internal combustion engines, exhaust gas recirculation (EGR) technology has been widely used. Its principle is to reintroduce part of the exhaust gas generated by the engine's combustion into the combustion chamber. Since the main components of the exhaust gas are water and CO2 with high specific heat capacity, they can absorb a large amount of heat, thereby reducing the maximum combustion temperature of the mixture in the cylinder, thereby reducing the amount of NOx generated. Therefore, exhaust gas recirculation technology can reduce the combustion temperature to a certain extent and obtain benefits in emissions or fuel consumption.

[0003] Since the EGR rate (the percentage of the exhaust gas mass flow rate of the EGR system entering the cylinder of the engine to the total intake air) will directly affect fuel consumption and combustion stability, the calculation and control of the exhaust gas mass flow rate of the EGR system is particularly important. At present, the most common calculation model of the exhaust gas mass flow rate of the EGR system is based on the absolute pressure value before and after the EGR valve, the temperature value before the valve, and the equivalent cross-sectional area of ​​the valve opening. However, this calculation method requires that the absolute pressure ratio before and after the EGR valve is less than a certain value to ensure the calculation accuracy, which increases the difficulty of exhaust gas flow control in the EGR system, and there are many sensors and actuators required to realize the above calculations on the engine. Therefore, a method for determining the exhaust gas mass flow rate of the EGR system is urgently needed to solve the above problems. Summary of the invention

[0004] In order to solve the above technical problems, the present disclosure provides a method, device, equipment, medium and vehicle for determining the exhaust gas mass flow rate.

[0005] A first aspect of an embodiment of the present disclosure provides a method for determining an exhaust gas mass flow rate, the method comprising:

[0006] Obtaining the air mass flow, first relative humidity, first pressure and first temperature of the fresh air entering the engine, and the second relative humidity, second pressure and second temperature of the mixed gas after the fresh air is mixed with the exhaust gas generated by the engine combustion;

[0007] calculating a first water content and a first molar amount of the fresh air based on the air mass flow rate, the first relative humidity, the first pressure, and the first temperature;

[0008] The exhaust gas flow rate is calculated based on the second relative humidity, the second pressure and the second temperature as well as the first water content and the first molar amount to obtain a first mass flow rate of the exhaust gas in the mixed gas, and the first mass flow rate is determined as the actual mass flow rate of the exhaust gas in the mixed gas.

[0009] A second aspect of an embodiment of the present disclosure provides a device for determining an exhaust gas mass flow rate, the device comprising:

[0010] A first acquisition module is used to acquire the air mass flow rate, the first relative humidity, the first pressure and the first temperature of the fresh air entering the engine, and the second relative humidity, the second pressure and the second temperature of the mixed gas after the fresh air is mixed with the exhaust gas generated by the engine combustion;

[0011] a first calculation module, configured to calculate a first water content and a first molar amount of the fresh air based on the air mass flow rate, the first relative humidity, the first pressure, and the first temperature;

[0012] The first determination module is used to calculate the exhaust gas flow rate based on the second relative humidity, the second pressure and the second temperature, the first water content and the first molar amount, obtain the first mass flow rate of the exhaust gas in the mixed gas, and determine the first mass flow rate as the actual mass flow rate of the exhaust gas in the mixed gas.

[0013] A third aspect of an embodiment of the present disclosure provides a computer device, the device comprising:

[0014] A memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the method for determining the exhaust gas mass flow rate of the first aspect mentioned above can be implemented.

[0015] A fourth aspect of an embodiment of the present disclosure provides a computer-readable storage medium, in which a computer program is stored. When the computer program is executed by a processor, the method for determining the exhaust gas mass flow rate of the first aspect mentioned above can be implemented.

[0016] The fifth aspect of the embodiment of the present disclosure provides a vehicle, which includes the exhaust gas mass flow determination device of the second aspect or the computer device of the third aspect or the computer-readable storage medium of the fourth aspect, and can implement the exhaust gas mass flow determination method of the first aspect.

[0017] Compared with the prior art, the technical solution provided by the embodiments of the present disclosure has the following advantages:

[0018] The disclosed embodiment obtains the air mass flow, a first relative humidity, a first pressure and a first temperature of the fresh air entering the engine, and the second relative humidity, a second pressure and a second temperature of the mixed gas after the fresh air is mixed with the exhaust gas generated by the engine combustion; calculates the first water content and the first molar amount of the fresh air based on the air mass flow, the first relative humidity, the first pressure and the first temperature; calculates the exhaust gas flow rate based on the second relative humidity, the second pressure and the second temperature and the first water content and the first molar amount to obtain the first mass flow rate of the exhaust gas in the mixed gas, and determines the first mass flow rate as the actual mass flow rate of the exhaust gas in the mixed gas, which is not restricted by the pressure ratio before and after the EGR valve, improves the determination accuracy of the exhaust gas mass flow rate in the EGR system, thereby reducing the difficulty of controlling the exhaust gas flow rate in the EGR system, and reduces the sensors and actuators required to determine the exhaust gas mass flow rate in the EGR system, thereby reducing the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0021] Figure 1 is a flow chart of a method for determining exhaust gas mass flow rate provided by an embodiment of the present disclosure;

[0022] Figure 2 is a schematic diagram of a low-pressure EGR system provided by an embodiment of the present disclosure;

[0023] Figure 3 is a flow chart of another method for determining the exhaust gas mass flow rate provided by an embodiment of the present disclosure;

[0024] Figure 4 is a structural schematic diagram of an exhaust gas mass flow determination device provided by an embodiment of the present disclosure;

[0025] Figure 5 It is a structural diagram of a computer device provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0026] In order to more clearly understand the above-mentioned objectives, features and advantages of the present disclosure, the scheme of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present disclosure, but the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, rather than all of the embodiments.

[0028] It should be understood that the various steps described in the method embodiments of the present disclosure may be performed in different orders and / or in parallel. In addition, the method embodiments may include additional steps and / or omit the steps shown. The scope of the present disclosure is not limited in this respect.

[0029] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0030] It should be noted that the modifications of "one" and "plurality" mentioned in the present disclosure are illustrative rather than restrictive, and those skilled in the art should understand that unless otherwise clearly indicated in the context, it should be understood as "one or more".

[0031] With the gradual improvement of the requirements for fuel consumption and emissions of internal combustion engines, exhaust gas recirculation (EGR) technology has been widely used. Its principle is to reintroduce part of the exhaust gas generated by the engine's combustion into the combustion chamber. Since the main components of the exhaust gas are water and CO2 with high specific heat capacity, they can absorb a large amount of heat, thereby reducing the maximum combustion temperature of the mixture in the cylinder, thereby reducing the amount of NOx generated. Therefore, exhaust gas recirculation technology can reduce the combustion temperature to a certain extent and obtain benefits in emissions or fuel consumption.

[0032] Since the EGR rate (the percentage of the exhaust gas mass flow rate of the EGR system entering the cylinder of the engine to the total intake air) will directly affect fuel consumption and combustion stability, the calculation and control of the exhaust gas mass flow rate of the EGR system is particularly important. At present, the most common calculation model of the exhaust gas mass flow rate of the EGR system is based on the absolute pressure value before and after the EGR valve, the temperature value before the valve, and the equivalent cross-sectional area of ​​the valve opening. However, this calculation method requires that the absolute pressure ratio before and after the EGR valve is less than a certain value to ensure the calculation accuracy, which increases the difficulty of exhaust gas flow control in the EGR system, and there are many sensors and actuators required to realize the above calculations on the engine. Therefore, a method for determining the exhaust gas mass flow rate of the EGR system is urgently needed to solve the above problems.

[0033] In response to the defects of related technologies in calculating EGR exhaust gas flow, the embodiments of the present disclosure provide a method, device, equipment, medium and vehicle for determining the exhaust gas mass flow rate, which is not limited by the pressure ratio before and after the EGR valve, improves the determination accuracy of the exhaust gas mass flow rate in the EGR system, thereby reducing the difficulty of controlling the exhaust gas flow rate in the EGR system, and reduces the sensors and actuators required to determine the exhaust gas mass flow rate in the EGR system, thereby reducing costs.

[0034] The method for determining the exhaust gas mass flow rate provided by the embodiment of the present disclosure can be executed by a computer device, which can be understood as any device with processing and computing capabilities, and the device can include but is not limited to electronic devices such as vehicle-mounted terminals, engine control devices, computers, etc.

[0035] In order to better understand the inventive concept of the embodiments of the present disclosure, the technical solutions of the embodiments of the present disclosure are described below in conjunction with exemplary embodiments.

[0036] Figure 1 is a flow chart of a method for determining the exhaust gas mass flow rate provided by an embodiment of the present disclosure, such as Figure 1 As shown, the method for determining the exhaust gas mass flow rate provided in this embodiment includes the following steps:

[0037] Step 110, obtaining the air mass flow, first relative humidity, first pressure and first temperature of the fresh air entering the engine, and the second relative humidity, second pressure and second temperature of the mixed gas after the fresh air is mixed with the exhaust gas generated by the engine combustion.

[0038] In the disclosed embodiment, it is assumed that the gaseous water in the gas will not undergo a phase change, that is, no condensed water will be generated. The mixed gas is a gas obtained by mixing fresh air with exhaust gas generated by engine combustion.

[0039] Fresh air is the fresh air that enters the engine. Air mass flow is the mass flow of fresh air. Mass flow refers to the mass of fluid passing through the effective cross-section of a closed pipe or open slot per unit time. The mass flow of fresh air can be measured by an air flow meter.

[0040] The first relative humidity is the relative humidity of fresh air. Relative humidity (RH) indicates the ratio of the absolute humidity in the air to the saturated absolute humidity at the same temperature and pressure, that is, the ratio of the mass of water vapor contained in a certain humid air to the mass of water vapor contained in saturated air at the same temperature and pressure. This ratio is expressed as a percentage. The relative humidity of fresh air can be measured by a humidity sensor or an air flow sensor.

[0041] The first pressure is the pressure of fresh air, that is, atmospheric pressure. The first temperature is the temperature of fresh air, which can be measured by a temperature sensor.

[0042] The second relative humidity is the relative humidity of the mixed gas. In the embodiment of the present disclosure, a humidity sensor and a temperature and pressure sensor can be set at the mixing point of the engine fresh air and exhaust gas, for example, Figure 2 As shown, a humidity sensor can be added between the throttle and the temperature and pressure sensor of the engine. As shown by the arrow in the figure, the humidity sensor can be used to measure the relative humidity of the mixed gas, that is, the second relative humidity, and the temperature and pressure sensor can be used to measure the second temperature and the second pressure of the mixed gas.

[0043] The second pressure is the pressure of the mixed gas, which can be measured by a pressure sensor.

[0044] The second temperature is the temperature of the mixed gas, which can be measured by a temperature sensor.

[0045] In the embodiment of the present disclosure, the computer device can obtain the air mass flow, the first relative humidity, the first pressure and the first temperature of the fresh air entering the engine, as well as the second relative humidity, the second pressure and the second temperature of the mixed gas after the fresh air is mixed with the exhaust gas generated by the engine combustion.

[0046] Step 120: Calculate a first water content and a first molar amount of the fresh air based on the air mass flow rate, the first relative humidity, the first pressure, and the first temperature.

[0047] In the embodiment of the present disclosure, the first water content can be understood as the amount of water contained in the fresh air in the mixed gas. The first molar amount is the molar amount of the fresh air in the mixed gas.

[0048] In the embodiment of the present disclosure, the computer device can calculate the first water content and the first molar amount of the fresh air based on the air mass flow rate, the first relative humidity, the first pressure and the first temperature.

[0049] In some embodiments, calculating the first water content and the first molar amount of the fresh air based on the air mass flow rate, the first relative humidity, the first pressure, and the first temperature may include steps 1101-1104:

[0050] Step 1101: Obtain a first molar mass of fresh air and a first saturated vapor pressure of water corresponding to a first temperature.

[0051] In the embodiment of the present disclosure, the computer device may pre-store the saturated vapor pressure of water corresponding to each temperature, and the saturated vapor pressure of water corresponds to the temperature one by one.

[0052] In the embodiment of the present disclosure, the computer device can obtain the first saturated vapor pressure of water and the first molar mass of fresh air corresponding to the first temperature from the storage space.

[0053] Step 1102: Calculate a first ratio of the air mass flow rate to the first molar mass to obtain a first molar amount of fresh air.

[0054] In the disclosed embodiment, the computer device may calculate a first ratio of the air mass flow rate to the first molar mass to obtain a first molar amount of fresh air.

[0055] Step 1103: Calculate a first product of the first saturated vapor pressure and the first relative humidity, and calculate a second ratio of the first product to the first pressure.

[0056] In the embodiment of the present disclosure, the computer device can calculate a first product of the first saturated vapor pressure and the first relative humidity, and calculate a second ratio of the first product to the first pressure.

[0057] Step 1104: multiply the first ratio by the second ratio to obtain a first moisture content of the fresh air.

[0058] In the disclosed embodiment, the computer device may multiply the first ratio by the second ratio to obtain a first moisture content of the fresh air.

[0059] Specifically, the first moisture content of fresh air can be calculated by the following formula:

[0060]

[0061] n air,水 Indicates the first water content of fresh air, in moles mol; m air Indicates the air mass flow rate of fresh air entering the engine; Psat1,水 represents the first saturated vapor pressure of water at the first temperature; RH represents the first relative humidity of fresh air, M air Indicates the first molar mass of fresh air; P atm Indicates the first pressure of fresh air, that is, atmospheric pressure.

[0062] Step 130, calculate the exhaust gas flow rate based on the second relative humidity, the second pressure and the second temperature as well as the first water content and the first molar amount to obtain a first mass flow rate of the exhaust gas in the mixed gas, and determine the first mass flow rate as the actual mass flow rate of the exhaust gas in the mixed gas.

[0063] In the embodiment of the present disclosure, the mass flow rate of the exhaust gas in the mixed gas is the mass flow rate of the exhaust gas contained in the mixed gas.

[0064] In the embodiment of the present disclosure, the computer device can calculate the exhaust gas flow rate based on the second relative humidity, the second pressure and the second temperature, the first water content and the first molar weight, obtain the first mass flow rate of the exhaust gas in the mixed gas, and determine the first mass flow rate as the actual mass flow rate of the exhaust gas in the mixed gas.

[0065] In some embodiments, calculating the exhaust gas flow rate based on the second relative humidity, the second pressure, the second temperature, the first water content, and the first molar amount to obtain a first mass flow rate of the exhaust gas in the mixed gas may include steps 1301-1303:

[0066] Step 1301: Obtain a second saturated vapor pressure of water corresponding to a second temperature.

[0067] In the embodiment of the present disclosure, the computer device can obtain the second saturated vapor pressure of water corresponding to the second temperature from the storage space.

[0068] Step 1302: Based on the combustion equation of the target fuel corresponding to the exhaust gas in the mixed gas in fresh air, determine the second molar mass of the exhaust gas and the proportional coefficient of water in the exhaust gas.

[0069] In the embodiment of the present disclosure, the combustion equation of the target fuel corresponding to the exhaust gas in the fresh air can be understood as the change process of each component in the process of the target fuel burning in the fresh air to generate exhaust gas.

[0070] In the embodiment of the present disclosure, the water ratio coefficient in the exhaust gas can be understood as the ratio of the amount of water in the exhaust gas to the total amount of the exhaust gas. The water ratio coefficient in the exhaust gas corresponds to the type of fuel, and the exhaust gas generated by the combustion of different types of fuels corresponds to the water ratio coefficient.

[0071] In the embodiment of the present disclosure, the computer device can determine the second molar mass of the exhaust gas and the proportion coefficient of water in the exhaust gas based on the combustion equation of the target fuel corresponding to the exhaust gas in the mixed gas in fresh air.

[0072] Specifically, based on the combustion equation of the target fuel corresponding to the exhaust gas in the mixed gas in the fresh air, determining the second molar mass of the exhaust gas and the proportional coefficient of water in the exhaust gas may include S11-S14:

[0073] S11. Based on a combustion equation of a target fuel corresponding to the exhaust gas in fresh air, obtain a total coefficient of components contained in the exhaust gas and a sub-coefficient of each component in the exhaust gas.

[0074] In the embodiment of the present disclosure, the computer device can obtain the total coefficient of the components contained in the exhaust gas and the sub-coefficient of each component in the exhaust gas based on the combustion equation of the target fuel corresponding to the exhaust gas in fresh air.

[0075] Specifically, the combustion equation of the target fuel corresponding to the exhaust gas in fresh air can be:

[0076]

[0077] Among them, C x H y O z Indicates the composition of the target fuel corresponding to the exhaust gas;

[0078] Indicates the composition of fresh air;

[0079] Indicates the total composition of fresh air required for combustion of target fuel;

[0080] x represents the sub-coefficient of carbon dioxide CO2 generated by the combustion of the target fuel in the exhaust gas;

[0081] The sub-coefficient representing the water H2O generated by the combustion of the target fuel in the exhaust gas;

[0082] It represents the sub-coefficient of nitrogen N2 generated by the combustion of the target fuel in the exhaust gas;

[0083] The total coefficient of the components contained in the exhaust gas can be expressed as:

[0084]

[0085] S12. Calculate the third ratio of the water sub-coefficient to the total coefficient to obtain a proportional coefficient of water in the exhaust gas.

[0086] In the disclosed embodiment, the computer device may calculate the third ratio of the water sub-coefficient to the total coefficient to obtain the proportional coefficient of water in the exhaust gas.

[0087] Specifically, the proportion coefficient C of water in the exhaust gas can be expressed as:

[0088]

[0089] S13. For each component, calculate the product of the sub-coefficient of the component and the molar mass of the component to obtain the sub-molar mass of the component in the exhaust gas.

[0090] In the embodiment of the present disclosure, the computer device can calculate, for each component, the product of the sub-coefficient of the component and the molar mass of the component to obtain the sub-molar mass of the component in the exhaust gas.

[0091] S14, summing up the sub-molar masses of the components to obtain a second molar mass of the exhaust gas.

[0092] In the disclosed embodiment, the computer device may sum up the sub-molar masses of the components in the exhaust gas to obtain the second molar mass of the exhaust gas.

[0093] Specifically, the second molar mass M of the exhaust gas EGR The calculation formula can be expressed as:

[0094]

[0095] Among them, "44" represents the molar mass of carbon dioxide, "18" represents the molar mass of water, and "28" represents the molar mass of nitrogen, and the unit is g / mol.

[0096] Step 1303, calculate the exhaust gas flow rate based on the second relative humidity, the second saturated vapor pressure, the second pressure, the first water content, the first molar amount, the second molar mass and the proportional coefficient of water to obtain a first mass flow rate of the exhaust gas in the mixed gas.

[0097] In an embodiment of the present disclosure, a computer device can calculate the exhaust gas flow rate based on the second relative humidity, the second saturated vapor pressure, the second pressure, the first water content, the first molar amount, the second molar mass and the proportional coefficient of water to obtain the first mass flow rate of the exhaust gas in the mixed gas.

[0098] Specifically,

[0099]

[0100] RH mix Indicates the second relative humidity of the mixed gas, P mix，水 Represents the water vapor pressure of the mixed gas, P sat2，水represents the second saturated vapor pressure of water corresponding to the second temperature.

[0101] P mix，水 =RH mix ·P sat2，水 (7)

[0102] n EGR，水 =n mix，水 -n air，水 (8)

[0103] n EGR，水 Indicates the water content of the exhaust gas in the mixed gas, in mol, n mix，水 Indicates the second water content of the mixed gas, in mol, n air，水 Indicates the first moisture content of fresh air.

[0104] According to the ideal gas state equation: PV = nRT, we get:

[0105]

[0106] P mix represents the second pressure of the mixed gas; and then we get:

[0107]

[0108] The second molar amount of the exhaust gas n EGR is the first mass flow rate of exhaust gas m EGR1 The second molar mass M of the exhaust gas EGR Ratio of:

[0109]

[0110]

[0111] n EGR，水 Indicates the water content of the exhaust gas in the mixed gas, M EGR Indicates the second molar mass of the exhaust gas, m EGR1 It represents the first mass flow rate of exhaust gas in the mixed gas, and C represents the proportion coefficient of water in the exhaust gas.

[0112] From the above formula, we can get the first mass flow rate m of the exhaust gas in the mixed gas: EGR1 The calculation formula is:

[0113]

[0114] The disclosed embodiment obtains a first water content of fresh air entering an engine and a second water content of a mixed gas after the fresh air is mixed with exhaust gas generated by engine combustion; performs a difference processing between the second water content and the first water content to obtain the exhaust gas water content of the exhaust gas in the mixed gas; performs exhaust gas flow calculation based on the exhaust gas water content, the proportional coefficient of water in the exhaust gas and the first molar mass of the exhaust gas to obtain the first mass flow of the exhaust gas in the mixed gas. The first mass flow of the exhaust gas in the mixed gas can be calculated by the water content of the exhaust gas contained in the mixed gas, the proportional coefficient of water in the exhaust gas and the molar mass of the exhaust gas. The first mass flow is determined as the actual mass flow of the exhaust gas in the mixed gas, which is not limited by the pressure ratio before and after the EGR valve, thereby improving the determination accuracy of the exhaust gas mass flow in the EGR system, thereby reducing the difficulty of controlling the exhaust gas flow in the EGR system, and reducing the sensors and actuators required for determining the exhaust gas mass flow in the EGR system, thereby reducing the cost.

[0115] In addition, since the exhaust gas of the EGR system contains a lot of water, the introduction of EGR technology also brings the risk of condensation to the engine intake system. In order to avoid condensation in the entire engine intake system, in related technologies, it is usually necessary to measure the relative humidity at the intake air flow meter to establish a corresponding condensation calculation model, so as to calculate and determine the condensation risk at various positions of the intake system, and avoid the condensation risk by adjusting the temperature or EGR rate. The condensation calculation model is added to the entire EGR flow calculation model, further increasing the difficulty of the entire system development. In the embodiment of the present disclosure, the introduction of humidity-related sensors can greatly simplify the condensation-related control strategy.

[0116] Figure 3 is a flow chart of a method for determining the exhaust gas mass flow rate provided by an embodiment of the present disclosure, such as Figure 3 As shown, the method for determining the exhaust gas mass flow rate provided in this embodiment includes the following steps:

[0117] Step 310: Obtain the air mass flow, first relative humidity, first pressure and first temperature of the fresh air entering the engine, and the second relative humidity, second pressure and second temperature of the mixed gas after the fresh air is mixed with the exhaust gas generated by the engine combustion.

[0118] Step 320: Calculate a first moisture content of the fresh air based on the air mass flow rate, the first relative humidity, the first pressure, and the first temperature.

[0119] The contents of steps 310 - 320 in the embodiment of the present disclosure may refer to the contents of steps 110 - 120 described above, and will not be repeated here.

[0120] Step 330: Obtain a second water content of the mixed gas.

[0121] In the embodiment of the present disclosure, the gaseous water in the gas will not undergo a phase change, that is, no condensed water will be generated. The second water content can be understood as the amount of water contained in the mixed gas.

[0122] In the embodiment of the present disclosure, the computer device can obtain a first water content of the fresh air and a second water content of the mixed gas obtained by mixing the fresh air with the exhaust gas.

[0123] Step 340: perform a difference process on the second water content and the first water content to obtain the water content of the exhaust gas in the mixed gas.

[0124] In the embodiment of the present disclosure, the exhaust gas water content can be understood as the amount of water contained in the exhaust gas. After obtaining the first water content of the fresh air and the second water content of the mixed gas, the computer device can perform a difference processing on the second water content and the first water content to obtain the exhaust gas water content of the exhaust gas in the mixed gas.

[0125] Specifically, the calculation formula for the water content of exhaust gas can be expressed as:

[0126] n EGR，水 =n mix，水 -n air，水 (14)

[0127] Among them, n EGR，水 Indicates the water content of the exhaust gas, in mol; n mix，水 The second unit for the water content of the mixed gas is mol; n air，水 It indicates the first water content of fresh air in mol.

[0128] Step 350: Calculate the waste gas flow rate based on the water content of the waste gas, the proportion coefficient of water in the waste gas, and the second molar mass of the waste gas to obtain the second mass flow rate of the waste gas in the mixed gas.

[0129] In the disclosed embodiment, the water ratio coefficient in the exhaust gas can be understood as the ratio of the amount of water in the exhaust gas to the total amount of the exhaust gas. The water ratio coefficient in the exhaust gas corresponds to the type of fuel one-to-one, and the exhaust gas generated by the combustion of different types of fuels corresponds to the water ratio coefficient one-to-one. The computer device can pre-store the water ratio coefficient corresponding to the exhaust gas generated by the combustion of different types of fuels.

[0130] In the embodiment of the present disclosure, the computer device can obtain the water proportion coefficient corresponding to the exhaust gas and the second molar mass of the exhaust gas from the storage space, calculate the exhaust gas flow rate based on the water content of the exhaust gas, the water proportion coefficient in the exhaust gas and the second molar mass of the exhaust gas, and obtain the second mass flow rate of the exhaust gas in the mixed gas.

[0131] Specifically, the exhaust gas flow rate is calculated based on the water content of the exhaust gas, the proportion coefficient of water in the exhaust gas, and the second molar mass of the exhaust gas to obtain the second mass flow rate of the exhaust gas in the mixed gas, which may include steps 3501-3503:

[0132] Step 3501: Determine the second molar mass of the exhaust gas and the proportion coefficient of water in the exhaust gas based on the combustion equation of the target fuel corresponding to the exhaust gas in fresh air.

[0133] The contents of the embodiment of the present disclosure may refer to the contents of the above step 1302 and will not be repeated here.

[0134] Step 3502: Calculate a fourth ratio of the water content in the exhaust gas to the proportional coefficient of water in the exhaust gas.

[0135] In the embodiment of the present disclosure, the computer device can calculate a fourth ratio of the water content of the exhaust gas to the proportional coefficient of water in the exhaust gas.

[0136] Step 3503: Calculate the product of the fourth ratio and the second molar mass to obtain the second mass flow rate of the exhaust gas in the mixed gas.

[0137] In the embodiment of the present disclosure, the computer device can calculate the product of the fourth ratio and the second molar mass to obtain the second mass flow rate of the exhaust gas in the mixed gas.

[0138] Specifically, the second mass flow rate m of the exhaust gas in the mixed gas EGR2 The calculation formula is:

[0139]

[0140] m EGR2 Indicates the second mass flow rate of exhaust gas in the mixed gas, M EGR It represents the second molar mass of the exhaust gas, and C represents the proportion coefficient of water in the exhaust gas.

[0141] Step 360: Calculate the difference between the first mass flow rate and the second mass flow rate.

[0142] In the embodiment of the present disclosure, after obtaining the first mass flow rate and the second mass flow rate of the exhaust gas in the mixed gas, the computer device may calculate the difference between the first mass flow rate and the second mass flow rate.

[0143] Step 370: When the difference between the first mass flow rate and the second mass flow rate is less than a preset threshold, the first mass flow rate or the second mass flow rate is determined as the actual mass flow rate of the exhaust gas in the mixed gas, or the average value of the first mass flow rate and the second mass flow rate is determined as the actual mass flow rate of the exhaust gas in the mixed gas.

[0144] In some embodiments, when the difference between the first mass flow rate and the second mass flow rate is less than a preset threshold, the computer device may determine the first mass flow rate as the actual mass flow rate of the exhaust gas in the mixed gas, or may determine the second mass flow rate as the actual mass flow rate of the exhaust gas in the mixed gas.

[0145] In other embodiments, when the difference between the first mass flow rate and the second mass flow rate is less than a preset threshold, the computer device can calculate the average value of the first mass flow rate and the second mass flow rate, and determine the average value of the first mass flow rate and the second mass flow rate as the actual mass flow rate of the exhaust gas in the mixed gas.

[0146] The preset threshold value can be set as needed and is not limited here.

[0147] Therefore, the mass flow rate of the exhaust gas in the mixed gas can be calculated by the water content of the fresh air entering the engine, the water content of the exhaust gas contained in the mixed gas, the proportion coefficient of water in the exhaust gas and the molar mass of the exhaust gas. This is not limited by the pressure ratio before and after the EGR valve, and the accuracy of determining the exhaust gas mass flow rate in the EGR system is improved, thereby reducing the difficulty of controlling the exhaust gas flow in the EGR system, and reducing the sensors and actuators required to determine the exhaust gas mass flow rate in the EGR system, thereby reducing costs.

[0148] In some embodiments of the present disclosure, after obtaining the actual mass flow rate of the exhaust gas in the mixed gas, the computer device can obtain the target mass flow rate of the exhaust gas in the exhaust gas recirculation system; calculate the difference between the actual mass flow rate and the target mass flow rate; based on the difference between the actual mass flow rate and the target mass flow rate, adjust the actual exhaust gas flow rate of the exhaust gas recirculation system to the target mass flow rate, thereby achieving control of the EGR exhaust gas flow rate.

[0149] The exhaust gas recirculation system can be understood as a system for controlling the EGR exhaust gas flow rate in the engine. The target mass flow rate of the exhaust gas can be understood as the mass flow rate that the exhaust gas recirculation system of the engine controls the EGR exhaust gas target to achieve.

[0150] Figure 4 is a schematic diagram of the structure of an exhaust gas mass flow determination device provided by an embodiment of the present disclosure, and the device can be understood as the above-mentioned computer device or a part of the functional modules in the above-mentioned computer device. Figure 4 As shown, the exhaust gas mass flow determination device 400 may include:

[0151] A first acquisition module 410 is used to acquire the air mass flow rate, the first relative humidity, the first pressure and the first temperature of the fresh air entering the engine, and the second relative humidity, the second pressure and the second temperature of the mixed gas after the fresh air is mixed with the exhaust gas generated by the engine combustion;

[0152] A first calculation module 420, for calculating a first water content and a first molar amount of the fresh air based on the air mass flow rate, the first relative humidity, the first pressure and the first temperature;

[0153] The first determination module 430 is used to calculate the exhaust gas flow rate based on the second relative humidity, the second pressure and the second temperature, the first water content and the first molar amount, to obtain the first mass flow rate of the exhaust gas in the mixed gas, and determine the first mass flow rate as the actual mass flow rate of the exhaust gas in the mixed gas.

[0154] Optionally, the first calculation module 420 includes:

[0155] A first acquisition submodule, used to acquire a first molar mass of fresh air and a first saturated vapor pressure of water corresponding to a first temperature;

[0156] A first calculation submodule, used for calculating a first ratio of the air mass flow rate to the first molar mass, to obtain a first molar amount of fresh air;

[0157] A second calculation submodule, used for calculating a first product of the first saturated vapor pressure and the first relative humidity, and calculating a second ratio of the first product to the first pressure;

[0158] The third calculation submodule is used to multiply the first ratio by the second ratio to obtain a first moisture content of the fresh air.

[0159] Optionally, the first determining module 430 includes:

[0160] A second acquisition submodule, used to acquire a second saturated vapor pressure of water corresponding to a second temperature;

[0161] A first determination submodule, for determining a second molar mass of the exhaust gas and a proportional coefficient of water in the exhaust gas based on a combustion equation of a target fuel corresponding to the exhaust gas in the mixed gas in fresh air;

[0162] The fourth calculation submodule is used to calculate the exhaust gas flow rate based on the second relative humidity, the second saturated vapor pressure, the second pressure, the first water content, the first molar amount, the second molar mass and the proportional coefficient of water to obtain the first mass flow rate of the exhaust gas in the mixed gas.

[0163] Optionally, the first determining submodule includes:

[0164] An acquisition unit, used for acquiring a total coefficient of components contained in the exhaust gas and a sub-coefficient of each component in the exhaust gas based on a combustion equation of a target fuel corresponding to the exhaust gas in fresh air;

[0165] a first calculation unit, for calculating a third ratio of the water sub-coefficient to the total coefficient, to obtain a proportional coefficient of water in the exhaust gas;

[0166] a second calculation unit, for calculating, for each component, the product of a sub-coefficient of the component and a molar mass of the component, to obtain a sub-molar mass of the component in the exhaust gas;

[0167] The summing unit is used to sum the sub-molar masses of each component to obtain the second molar mass of the exhaust gas.

[0168] Optionally, the exhaust gas mass flow determination device 400 may include:

[0169] A second acquisition module, used for acquiring a target mass flow rate of exhaust gas in the exhaust gas recirculation system;

[0170] A second calculation module, used for calculating the difference between the actual mass flow rate and the target mass flow rate;

[0171] An adjustment module is configured to adjust the actual exhaust gas flow rate of the exhaust gas recirculation system to the target mass flow rate based on a difference between the actual mass flow rate and the target mass flow rate.

[0172] Optionally, the exhaust gas mass flow determination device 400 may include:

[0173] A third acquisition module, used to acquire a second water content of the mixed gas;

[0174] a third calculation module, for performing a difference processing on the second water content and the first water content to obtain the water content of the exhaust gas in the mixed gas;

[0175] a fourth calculation module, configured to calculate the exhaust gas flow rate based on the water content of the exhaust gas, the proportional coefficient of water in the exhaust gas, and the first molar mass of the exhaust gas, to obtain a second mass flow rate of the exhaust gas in the mixed gas;

[0176] a fifth calculation module, configured to calculate a difference between the first mass flow rate and the second mass flow rate;

[0177] The second determination module is used to determine the first mass flow rate or the second mass flow rate as the actual mass flow rate of the exhaust gas in the mixed gas when the difference between the first mass flow rate and the second mass flow rate is less than a preset threshold, or to determine the average value of the first mass flow rate and the second mass flow rate as the actual mass flow rate of the exhaust gas in the mixed gas.

[0178] Optionally, the fourth calculation module includes:

[0179] A second determination submodule, configured to determine a second molar mass of the exhaust gas and a proportional coefficient of water in the exhaust gas based on a combustion equation of a target fuel corresponding to the exhaust gas in the fresh air;

[0180] a fifth calculation submodule, configured to calculate a fourth ratio of the water content of the exhaust gas to a proportional coefficient of water in the exhaust gas;

[0181] The sixth calculation submodule is used to calculate the product of the fourth ratio and the second molar mass to obtain a second mass flow rate of the exhaust gas in the mixed gas.

[0182] The exhaust gas mass flow determination device provided in the embodiments of the present disclosure can implement the method of any of the above embodiments, and its execution method and beneficial effects are similar, which will not be repeated here.

[0183] The embodiments of the present disclosure also provide a computer device, which includes a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the method of any of the above embodiments can be implemented, and its execution method and beneficial effects are similar and will not be repeated here.

[0184] Figure 5 is a schematic diagram of the structure of a computer device provided by an embodiment of the present disclosure, such as Figure 5 As shown, the computer device 500 may include a processor 510 and a memory 520, wherein the memory 520 stores a computer program 521, and when the computer program 521 is executed by the processor 510, the method provided by any of the above embodiments can be implemented, and its execution method and beneficial effects are similar, which will not be repeated here.

[0185] Of course, to simplify, Figure 5 Only some of the components related to the present invention in the computer device 500 are shown, and components such as a bus, an input / output interface, an input device, and an output device are omitted. In addition, according to specific application conditions, the computer device 500 may also include any other appropriate components.

[0186] An embodiment of the present disclosure provides a computer-readable storage medium, in which a computer program is stored. When the computer program is executed by a processor, the method of any of the above embodiments can be implemented. The execution method and beneficial effects are similar and will not be repeated here.

[0187] The above-mentioned computer readable storage medium can adopt any combination of one or more readable media. The readable medium can be a readable signal medium or a readable storage medium. The readable storage medium can include, for example, but is not limited to, a system, device or device of electricity, magnetism, light, electromagnetic, infrared, or semiconductor, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0188] The computer program may be written in any combination of one or more programming languages ​​to write program codes for performing the operations of the disclosed embodiments, including object-oriented programming languages ​​such as Java, C++, etc., and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer device, partially on the user's device, as a separate software package, partially on the user's computer device and partially on a remote computer device, or entirely on a remote computer device or server.

[0189] An embodiment of the present disclosure provides a vehicle, which includes the above-mentioned exhaust gas mass flow determination device or the above-mentioned computer device or the above-mentioned computer-readable storage medium, and can implement the method of any of the above-mentioned embodiments. The execution method and beneficial effects are similar and will not be repeated here.

[0190] The above description is only a preferred embodiment of the present disclosure and an explanation of the technical principles used. Those skilled in the art should understand that the scope of disclosure involved in the present disclosure is not limited to the technical solutions formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above disclosed concept. For example, the above features are replaced with the technical features with similar functions disclosed in the present disclosure (but not limited to) by each other to form a technical solution.

[0191] In addition, although each operation is described in a specific order, this should not be understood as requiring these operations to be performed in the specific order shown or in a sequential order. Under certain circumstances, multitasking and parallel processing may be advantageous. Similarly, although some specific implementation details are included in the above discussion, these should not be interpreted as limiting the scope of the present disclosure. Some features described in the context of a separate embodiment can also be implemented in a single embodiment in combination. On the contrary, the various features described in the context of a single embodiment can also be implemented in multiple embodiments individually or in any suitable sub-combination mode.

[0192] The above description is only a specific embodiment of the present disclosure, so that those skilled in the art can understand or implement the present disclosure. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure will not be limited to the embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for determining the mass flow rate of exhaust gas, characterized in that: include: Obtaining the air mass flow, first relative humidity, first pressure and first temperature of the fresh air entering the engine, and the second relative humidity, second pressure and second temperature of the mixed gas after the fresh air is mixed with the exhaust gas generated by the combustion of the engine; calculating a first water content and a first molar amount of the fresh air based on the air mass flow rate, the first relative humidity, the first pressure, and the first temperature; The exhaust gas flow rate is calculated based on the second relative humidity, the second pressure and the second temperature as well as the first water content and the first molar amount to obtain a first mass flow rate of the exhaust gas in the mixed gas, and the first mass flow rate is determined as the actual mass flow rate of the exhaust gas in the mixed gas.

2. The method according to claim 1, characterized in that The calculating the first water content and the first molar amount of the fresh air based on the air mass flow rate, the first relative humidity, the first pressure and the first temperature comprises: Obtaining a first molar mass of the fresh air and a first saturated vapor pressure of water corresponding to the first temperature; Calculating a first ratio of the air mass flow rate to the first molar mass to obtain a first molar amount of the fresh air; calculating a first product of the first saturated vapor pressure and the first relative humidity, and calculating a second ratio of the first product to the first pressure; The first ratio is multiplied by the second ratio to obtain a first moisture content of the fresh air.

3. The method according to claim 1, characterized in that The calculating the exhaust gas flow rate based on the second relative humidity, the second pressure, the second temperature, the first water content, and the first molar amount to obtain a first mass flow rate of the exhaust gas in the mixed gas includes: Obtaining a second saturated vapor pressure of water corresponding to the second temperature; determining a second molar mass of the exhaust gas and a proportional coefficient of water in the exhaust gas based on a combustion equation of a target fuel corresponding to the exhaust gas in the mixed gas in the fresh air; The exhaust gas flow rate is calculated based on the second relative humidity, the second saturated vapor pressure, the second pressure, the first water content, the first molar amount, the second molar mass and the proportional coefficient of water to obtain a first mass flow rate of the exhaust gas in the mixed gas.

4. The method according to claim 3, characterized in that The determining the second molar mass of the exhaust gas and the proportional coefficient of water in the exhaust gas based on a combustion equation of a target fuel corresponding to the exhaust gas in the mixed gas in the fresh air comprises: Based on a combustion equation of a target fuel corresponding to the exhaust gas in the fresh air, obtaining a total coefficient of components contained in the exhaust gas and a sub-coefficient of each component in the exhaust gas; calculating a third ratio of the water sub-coefficient to the total coefficient to obtain a proportional coefficient of water in the exhaust gas; For each of the components, calculating the product of the sub-coefficient of the component and the molar mass of the component to obtain the sub-molar mass of the component in the exhaust gas; The sub-molar masses of the components are summed to obtain the second molar mass of the exhaust gas.

5. The method according to claim 1, characterized in that After determining the first mass flow rate as the actual mass flow rate of the exhaust gas in the mixed gas, the method further includes: Obtaining a target mass flow rate of exhaust gas in an exhaust gas recirculation system; calculating a difference between the actual mass flow rate and the target mass flow rate; The actual exhaust gas flow rate of the exhaust gas recirculation system is adjusted to the target mass flow rate based on a difference between the actual mass flow rate and the target mass flow rate.

6. The method according to claim 1, characterized in that After obtaining the first mass flow rate of the exhaust gas in the mixed gas, the method further includes: obtaining a second water content of the mixed gas; performing a difference processing on the second water content and the first water content to obtain the water content of the exhaust gas in the mixed gas; Calculating the waste gas flow rate based on the water content of the waste gas, the proportion coefficient of water in the waste gas, and the second molar mass of the waste gas to obtain a second mass flow rate of the waste gas in the mixed gas; calculating a difference between the first mass flow rate and the second mass flow rate; When the difference between the first mass flow rate and the second mass flow rate is less than a preset threshold, the first mass flow rate or the second mass flow rate is determined as the actual mass flow rate of the exhaust gas in the mixed gas, or the average value of the first mass flow rate and the second mass flow rate is determined as the actual mass flow rate of the exhaust gas in the mixed gas.

7. The method according to claim 6, characterized in that The calculating the waste gas flow rate based on the water content of the waste gas, the proportion coefficient of water in the waste gas, and the second molar mass of the waste gas to obtain the second mass flow rate of the waste gas in the mixed gas includes: determining a second molar mass of the exhaust gas and a proportional coefficient of water in the exhaust gas based on a combustion equation of a target fuel corresponding to the exhaust gas in the fresh air; calculating a fourth ratio of the water content of the exhaust gas to a proportional coefficient of water in the exhaust gas; The product of the fourth ratio and the second molar mass is calculated to obtain a second mass flow rate of the exhaust gas in the mixed gas.

8. A device for determining the mass flow rate of exhaust gas, characterized in that: include: A first acquisition module, used to acquire the air mass flow, first relative humidity, first pressure and first temperature of the fresh air entering the engine, and second relative humidity, second pressure and second temperature of the mixed gas after the fresh air is mixed with the exhaust gas generated by the combustion of the engine; a first calculation module, configured to calculate a first water content and a first molar amount of the fresh air based on the air mass flow rate, the first relative humidity, the first pressure and the first temperature; The first determination module is used to calculate the exhaust gas flow rate based on the second relative humidity, the second pressure and the second temperature and the first water content and the first molar amount to obtain a first mass flow rate of the exhaust gas in the mixed gas, and determine the first mass flow rate as the actual mass flow rate of the exhaust gas in the mixed gas.

9. A computer device, characterized in that: include: A memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the method for determining the exhaust gas mass flow rate as described in any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium, characterized in that: The storage medium stores a computer program, and when the computer program is executed by a processor, the method for determining the exhaust gas mass flow rate according to any one of claims 1 to 7 is implemented.

11. A vehicle, characterized in that: The vehicle comprises the exhaust gas mass flow determination device according to claim 8 or the computer device according to claim 9 or the computer-readable storage medium according to claim 10 .

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