Diesel engine aftertreatment unit pressure drop prediction method, system, device, and diesel engine vehicle

Abstract

The present disclosure relates to a diesel engine aftertreatment unit pressure drop prediction system, method, device and diesel engine vehicle, wherein the system comprises: a parameter acquisition module for acquiring diesel engine operating parameters and aftertreatment system parameters, wherein the operating parameters comprise engine exhaust parameters, carrier parameters and catalyst coating parameters; a carrier pressure drop calculation module for calculating straight-through carrier pressure drop and wall-flow carrier pressure drop by using the diesel engine operating parameters acquired by the parameter acquisition module; and a pressure drop prediction module for performing cumulative summation on the straight-through carrier pressure drop and the wall-flow carrier pressure drop calculated by the carrier pressure drop calculation module to obtain the total pressure drop of the diesel engine aftertreatment unit as a prediction result. The system and method of the present disclosure can predict the pressure drop value of the catalytic unit, and the model can compare the model pressure drop value with the measured pressure drop value and realize self-calibration and correction, thereby improving the accuracy and applicability of the pressure drop prediction value.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of diesel engine data processing, and more particularly to a diesel engine aftertreatment unit pressure drop prediction method and system and a diesel engine vehicle. BACKGROUND

[0002] In order to reduce the pollutant emissions of the engine, a purification treatment system arranged outside the engine is referred to as an aftertreatment system. The exhaust gas discharged from the cylinder of the engine passes through the aftertreatment system, and most of the gaseous pollutants and particulate matters in the exhaust gas are removed, and the relatively clean gas flow is finally discharged into the atmosphere through the exhaust tailpipe. The main structure of the aftertreatment system includes various catalytic units inside, an external packaging system, sensors and actuators responsible for measurement and control, etc.

[0003] When the gas flow passes through a certain pipeline or material, the drop value of the pressure (pressure) thereof is referred to as pressure drop. For the engine exhaust and the aftertreatment system, the pressure drop reflects the resistance suffered by the exhaust gas flow, and the greater the pressure drop, the higher the engine fuel consumption. Therefore, the pressure drop is an important indicator of the performance of the engine and the aftertreatment system.

[0004] The prior art does not have a system and method for real-time calculation or prediction of the pressure drop of the aftertreatment system based on the theory of laminar flow and percolation, which is a problem to be solved. SUMMARY

[0005] To solve the technical problem that the prior art does not have a system and method for real-time calculation or prediction of the pressure drop of the aftertreatment system based on the theory of laminar flow and percolation.

[0006] To achieve the above technical purpose, the present disclosure provides a diesel engine aftertreatment unit pressure drop prediction system, comprising:

[0007] A parameter acquisition module is configured to acquire diesel engine operating parameters and aftertreatment system parameters, wherein the operating parameters include engine exhaust parameters, carrier parameters and catalyst coating parameters.

[0008] A carrier pressure drop calculation module is configured to calculate the straight-through carrier pressure drop and the wall-flow carrier pressure drop by using the diesel engine operating parameters acquired by the parameter acquisition module.

[0009] A pressure drop prediction module is configured to add up the straight-through carrier pressure drop and the wall-flow carrier pressure drop calculated by the carrier pressure drop calculation module to obtain the total pressure drop of the diesel engine aftertreatment unit as a prediction result.

[0010] Further, the carrier pressure drop calculation module is specifically configured to:

[0011] The straight-through carrier pressure drop of the catalytic unit with a straight-through carrier is calculated by the following formula:

[0012]

[0013] wherein,

[0014] wherein, a=a0-2a c ;

[0015] wherein, a0 is obtained by the following formula: (a0+w) 2 CPSM=1;

[0016] In the formula, Δp S and Δp contraction represents the pressure drop caused by the local resistance of the pipeline contraction when the gas flows to the inlet of the catalytic unit, i.e. the straight-through carrier pressure drop;

[0017] ξ is the expansion and contraction resistance coefficient of the inlet and outlet pipeline;

[0018] ρ is the density of the gas flow;

[0019] u in is the speed of the engine exhaust gas flowing into the carrier channel;

[0020] CPSM is the number of channels per square meter on the end face circle of the carrier, which is obtained by the carrier parameter collected by the parameter collection module;

[0021] Q V is the volume flow of the engine exhaust gas, which is obtained by the engine exhaust gas parameter collected by the parameter collection module;

[0022] D is the diameter of the catalytic unit, which is obtained by the carrier parameter collected by the parameter collection module;

[0023] a is the side length of the channel in the catalytic unit;

[0024] a0 is the side length of the channel possessed by the carrier itself in the catalytic unit, and

[0025] a c is the coating thickness of the catalyst coating in the catalytic unit, which is obtained by the catalyst coating parameter collected by the parameter collection module;

[0026] w is the wall thickness value possessed by the carrier itself in the catalytic unit, which is obtained by the carrier parameter collected by the parameter collection module.

[0027] Further, the carrier pressure drop calculation module is specifically used for:

[0028] calculating the wall flow carrier pressure drop of the catalytic unit with the wall flow carrier by the following formula:

[0029] Δp F = Δp friction,in+ Δp w + Δp friction,out ; wherein

[0030]

[0031] wherein

[0032]

[0033]

[0034]

[0035] Δp friction,in represents the pressure drop due to the frictional shear stress along the flow path of the inlet channel of the wall-flow catalytic unit;

[0036] Δp friction,out represents the pressure drop due to the frictional shear stress along the flow path of the outlet channel of the wall-flow catalytic unit;

[0037] Δp w represents the pressure drop due to the permeation of the gas through the filter wall of the wall-flow carrier;

[0038] f represents the frictional resistance coefficient along the flow path;

[0039] μ represents the viscosity of the gas flow;

[0040] T represents the temperature of the engine exhaust gas, which is obtained by the engine exhaust gas parameter acquired by the parameter acquisition module;

[0041] L represents the length of the catalytic unit carrier, which is obtained by the carrier parameter acquired by the parameter acquisition module;

[0042] cdr represents the asymmetry ratio of the wall-flow carrier, which is equal to the ratio of the inlet / outlet channel side length, and is obtained by the carrier parameter acquired by the parameter acquisition module;

[0043] u w0 represents the average flow velocity of the gas flow through the filter wall of the wall-flow carrier;

[0044] k represents the permeability of the filter wall of the wall-flow carrier;

[0045] d pore represents the pore diameter of the micropore of the filter wall of the wall-flow carrier, which is obtained by the carrier parameter acquired by the parameter acquisition module;

[0046] ε represents the porosity of the micropore of the filter wall of the wall-flow carrier, which is obtained by the carrier parameter acquired by the parameter acquisition module.

[0047] Further, the pressure drop prediction module calculates the total pressure drop of the diesel engine aftertreatment unit as a prediction result through the following formula:

[0048]

[0049] wherein Δp total represents the total pressure drop of all catalytic units of the entire aftertreatment system;

[0050] Δp S,i represents the pressure drop of the i-th straight-through carrier of the catalytic unit;

[0051] Δp F,j represents the pressure drop of the j-th wall-flow carrier of the catalytic unit;

[0052] i and j are positive integers; m is the number of catalytic units of the straight-through carrier; and n is the number of catalytic units of the wall-flow carrier.

[0053] Further, the system further comprises:

[0054] a correction and calibration module configured to compare the calculated pressure drop values of the catalytic units with the actually measured pressure drop values of the catalytic units, and correct and calibrate the pressure drop prediction module by adjusting the resistance coefficients.

[0055] Further, the correction and calibration module corrects and calibrates through the following formula:

[0056]

[0057] β i represents the resistance coefficient of the i-th straight-through catalytic unit;

[0058] γ j represents the resistance coefficient of the j-th wall-flow catalytic unit.

[0059] To achieve the above technical purposes, the present disclosure can also provide a diesel engine aftertreatment unit pressure drop prediction method, comprising:

[0060] acquiring diesel engine operating parameters and aftertreatment system parameters, wherein the operating parameters include engine exhaust parameters, carrier parameters and catalyst coating parameters;

[0061] calculating the pressure drop of the straight-through carrier and the pressure drop of the wall-flow carrier using the diesel engine operating parameters acquired by the parameter acquisition module;

[0062] accumulating and summing the pressure drop of the straight-through carrier and the pressure drop of the wall-flow carrier calculated by the carrier pressure drop calculation module to obtain the total pressure drop of the diesel engine aftertreatment unit as a prediction result.

[0063] Further, the method further comprises: comparing the calculated pressure drop value of each catalytic unit with the actually measured pressure drop value of each catalytic unit, and correcting and calibrating the pressure drop prediction module by adjusting the resistance coefficient.

[0064] To achieve the above technical purposes, the present disclosure further provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the diesel engine aftertreatment unit pressure drop prediction method when executing the computer program.

[0065] In another aspect, the present disclosure further provides a diesel locomotive equipped with the above-mentioned electronic device and the above-mentioned diesel engine aftertreatment unit pressure drop prediction system.

[0066] The present disclosure has the following beneficial effects:

[0067] The system and method of the present disclosure are based on the laminar flow theory and the percolation theory, and a prediction calculation model of the pressure drop of each catalytic unit in the diesel engine aftertreatment system is constructed. By inputting the exhaust conditions (flow rate, temperature, density, etc.) of the engine steady state point and the parameters (size, wall thickness, catalyst coating thickness, etc.) of each catalytic unit, the pressure drop value of the catalytic unit can be predicted. The model can compare the model pressure drop value with the measured pressure drop value, and realize self-calibration and correction, thereby improving the accuracy and applicability of the pressure drop prediction value. The method and model can be used for the design and selection of aftertreatment catalytic units, and can save resource and time costs. BRIEF DESCRIPTION OF DRAWINGS

[0068] Figure 1 A structural schematic diagram of the system of embodiment 1 of the present disclosure is shown;

[0069] Figure 2 A structural schematic diagram of the improved system of embodiment 1 of the present disclosure is shown;

[0070] Figure 3 A schematic diagram of the microstructure and gas flow of the straight-through carrier is shown;

[0071] Figure 4 A schematic diagram of the microstructure and gas flow of the wall-flow carrier is shown;

[0072] Figure 5 A flowchart of the method of embodiment 2 of the present disclosure is shown;

[0073] Figure 6 A structural schematic diagram of embodiment 3 of the present disclosure is shown. DETAILED DESCRIPTION

[0074] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood, however, that the description is merely exemplary and is not intended to limit the scope of the present disclosure. Also, in the following description, the description of well-known structures and techniques is omitted to avoid unnecessarily obscuring the concept of the present disclosure.

[0075] In the drawings, various structural diagrams according to embodiments of the present disclosure are shown. These diagrams are not drawn to scale in which certain details are exaggerated for clarity of presentation and can omit certain details. The shapes of various regions, layers, and the relative size and positional relationship therebetween shown in the drawings are merely exemplary, and in actuality, they can be deviated due to manufacturing tolerances or technical limitations, and a person skilled in the art can additionally design regions / layers having different shapes, sizes, and relative positions according to actual needs.

[0076] Explanation of terms involved in the present disclosure:

[0077] Aftertreatment system: refers to a purification treatment system arranged outside the engine in order to reduce the pollutant emission of the engine. The exhaust gas discharged from the cylinder of the engine passes through the aftertreatment system, in which most of the gaseous pollutants and particulate matters are removed, and the relatively clean gas flow is finally discharged into the atmosphere through the exhaust tailpipe. The main structure of the aftertreatment system includes various catalytic units inside, an external packaging system, sensors and actuators responsible for measurement and control, etc.

[0078] Pressure drop: also known as back pressure, refers to the drop in pressure (pressure) of a gas flow when it flows through a certain section of pipeline or material. For engine exhaust and aftertreatment system, the pressure drop reflects the resistance suffered by the exhaust gas flow, the greater the pressure drop, the higher the engine fuel consumption. Therefore, the pressure drop is an important indicator of the performance of the engine and the aftertreatment system.

[0079] Catalytic unit: mainly includes a carrier and a catalyst coating. The carrier is generally a material with a porous structure such as honeycomb ceramic. The catalyst coating is applied to the carrier to achieve purification of gaseous pollutants or particulate pollutants. The carrier can be divided into straight-through carrier and wall-flow carrier according to the flow of the gas flow therein. According to the function and type, the commonly used aftertreatment catalytic unit of diesel engine can be divided into catalytic oxidizer (Diesel Oxidation Catalyst, abbreviated as DOC, using straight-through carrier), particulate filter (Diesel Particle Filter, abbreviated as DPF, using wall-flow carrier), selective catalytic reduction (straight-through carrier), etc. The pressure drop of the catalytic unit includes local resistance pressure drop, along-the-way friction pressure drop, and wall permeation pressure drop, etc.

[0080] Steady state point: refers to the state that the speed, torque, power, exhaust temperature, exhaust flow and the like of the engine reach stability within a certain time, and remain unchanged within a certain time. The performance of each component of the engine at the steady state point is a key concern in engine design and development work.

[0081] Embodiment one:

[0082] As shown in Figure 1 :

[0083] The present disclosure provides a diesel engine aftertreatment unit pressure drop prediction system, comprising:

[0084] A parameter acquisition module is configured to acquire diesel engine operating parameters and aftertreatment system parameters, wherein the operating parameters include engine exhaust parameters, carrier parameters and catalyst coating parameters.

[0085] A carrier pressure drop calculation module is configured to calculate the straight-through carrier pressure drop and the wall-flow carrier pressure drop using the diesel engine operating parameters acquired by the parameter acquisition module.

[0086] A pressure drop prediction module is configured to add up and sum the straight-through carrier pressure drop and the wall-flow carrier pressure drop calculated by the carrier pressure drop calculation module to obtain the total pressure drop of the diesel engine aftertreatment unit as a prediction result.

[0087] Further, the carrier pressure drop calculation module is specifically configured to:

[0088] The straight-through carrier pressure drop of the catalytic unit with a straight-through carrier is calculated by the following formula:

[0089]

[0090] wherein,

[0091] wherein, a=a0-2a c ;

[0092] wherein, a0 is obtained by the following formula: (a0+w) 2 CPSM=1;

[0093] In the formula, Δp S and Δp contraction represent the pressure drop caused by the local resistance of the pipeline contraction when the gas flows into the inlet of the catalytic unit, i.e. the straight-through carrier pressure drop;

[0094] ξ is the expansion and contraction resistance coefficient of the inlet and outlet pipelines;

[0095] ρ is the density of the gas flow;

[0096] u in is the speed of the engine exhaust flowing into the carrier channel;

[0097] CPSM is the number of channels per square meter on the end face circle of the carrier, which is obtained by the carrier parameter acquired by the parameter acquisition module;

[0098] Q V is the volumetric flow rate of engine exhaust, which is obtained by the engine exhaust parameter acquired by the parameter acquisition module;

[0099] D is the diameter of the catalytic unit, which is obtained by the carrier parameter acquired by the parameter acquisition module;

[0100] a is the side length of the channel in the catalytic unit;

[0101] a0 is the side length of the channel possessed by the carrier itself in the catalytic unit, and

[0102] a c is the coating thickness of the catalyst coating in the catalytic unit, which is obtained by the catalyst coating parameter acquired by the parameter acquisition module;

[0103] w is the wall thickness value possessed by the carrier itself in the catalytic unit, which is obtained by the carrier parameter acquired by the parameter acquisition module.

[0104] Further, the carrier pressure drop calculation module is specifically used for:

[0105] calculating the wall flow carrier pressure drop of the catalytic unit with the wall flow carrier by the following formula:

[0106] Δp F = Δp friction,in + Δp w + Δp friction,out ; wherein,

[0107]

[0108] wherein,

[0109]

[0110]

[0111]

[0112] Δp friction,in represents the pressure drop caused by the frictional shear stress along the flow path of the inlet channel gas flow of the wall flow catalytic unit;

[0113] Δp friction,out represents the pressure drop caused by the frictional shear stress along the flow path of the outlet channel gas flow of the wall flow catalytic unit;

[0114] Δp wrepresents the pressure drop generated by the permeation of the gas as it passes through the filter walls of the wall-flow carrier;

[0115] f represents the frictional resistance coefficient along the path;

[0116] μ represents the viscosity of the gas flow;

[0117] T represents the temperature of the engine exhaust, which is obtained by the engine exhaust parameter acquired by the parameter acquisition module;

[0118] L represents the length of the catalytic unit carrier, which is obtained by the carrier parameter acquired by the parameter acquisition module;

[0119] cdr represents the asymmetry ratio of the wall-flow carrier, which is equal to the ratio of the inlet / outlet passage side length, which is obtained by the carrier parameter acquired by the parameter acquisition module;

[0120] u w0 represents the average flow velocity of the gas flow as it passes through the filter walls of the wall-flow carrier;

[0121] k represents the permeability of the filter walls of the wall-flow carrier;

[0122] d pore represents the pore size of the micropores of the filter walls of the wall-flow carrier, which is obtained by the carrier parameter acquired by the parameter acquisition module;

[0123] ε represents the porosity of the micropores of the filter walls of the wall-flow carrier, which is obtained by the carrier parameter acquired by the parameter acquisition module.

[0124] Further, the pressure drop prediction module specifically calculates the total pressure drop of the diesel engine aftertreatment unit as a prediction result by the following formula:

[0125]

[0126] wherein Δp total represents the total pressure drop of all catalytic units of the entire aftertreatment system;

[0127] Δp S,i represents the straight-through carrier pressure drop of the catalytic unit of the i-th straight-through carrier;

[0128] Δp F,j represents the wall-flow carrier pressure drop of the catalytic unit of the j-th wall-flow carrier;

[0129] i and j are positive integers; m is the number of catalytic units of the straight-through carrier; and n is the number of catalytic units of the wall-flow carrier.

[0130] Further, the system further comprises:

[0131] The correction and calibration module is used to compare the calculated pressure drop values of each catalytic unit with the actually measured pressure drop values of each catalytic unit, and correct and calibrate the pressure drop prediction module by adjusting the resistance coefficient.

[0132] Further, the correction and calibration module is specifically corrected and calibrated by the following formula:

[0133]

[0134] β i represents the resistance coefficient of the i-th through-flow catalytic unit;

[0135] γ j represents the resistance coefficient of the j-th wall-flow catalytic unit.

[0136] Catalytic unit with through-flow carrier:

[0137] As shown in the following formula: Figure 3

[0138] When the gas flow enters the inlet of the catalytic unit, due to the small channel cross-sectional area of the catalytic unit, the pipe contraction occurs, thereby generating the local resistance (pressure drop) Δp contraction caused by pipe contraction, which is calculated by the following series of formulas.

[0139]

[0140]

[0141] a = a0-2a c

[0142] (a0+w) 2 CPSM = 1

[0143] When the gas flow flows in the carrier of the through-flow catalytic unit, the pressure loss (pressure drop) caused by the frictional shear stress along the path can be calculated by the following series of formulas.

[0144]

[0145] μ = 8.32 x 10 -15 T 3 -2.96 x 10 -11 T 2 + 6.24 x 10 -8 T + 2.31 x 10 -6

[0146] When the gas flow flows out of the outlet of the catalytic unit, the pipe expansion occurs at this time, thereby generating the local resistance (pressure drop) Δp expand caused by pipe expansion, which is calculated by the following formula.​

[0147]

[0148] For catalytic units using straight-through carriers, the total pressure drop Δp S is the sum of the above three.

[0149] Δp S = Δp contraction + Δp friction + Δp expand

[0150] For catalytic units with wall-flow carriers:

[0151] As shown in: Figure 4

[0152] For wall-flow carriers, first, the local resistance pressure drop Δp contraction caused by the contraction of the inlet pipe and the local resistance pressure drop Δp expand caused by the expansion of the outlet pipe still exist, but their values are low compared to other pressure drops of the total pressure drop, and can generally be ignored.

[0153] Secondly, for wall-flow carriers, in the inlet and outlet channels, a part of the pressure drop will still be generated due to the friction along the way, but because the gas simultaneously flows forward and laterally along the wall, the calculation forms of the flow rate u in of the gas flowing into the inlet channel, the pressure drop along the way Δp friction,in of the inlet channel, and the pressure drop along the way Δp friction,out of the outlet channel will all change.

[0154]

[0155]

[0156]

[0157] It can be seen from the above formula that for wall-flow carriers with symmetrical inlet and outlet structures (cdr = 1), the pressure drops along the way of the inlet and outlet channels are equal (Δp friction,in = Δp friction,out ); and for wall-flow carriers with asymmetrical structures (cdr ≠ 1, and the actual products are mostly cdr > 1), the pressure drops along the way of the inlet and outlet channels are not equal (Δp friction,in ≠ Δp friction,out , and the actual products are mostly Δp friction,in < Δp friction,out ).

[0158] ​In addition, the wall-flow substrate must also take into account the permeation pressure drop Δp w The calculation method of Δp

[0159]

[0160]

[0161]

[0162] The above contents are integrated and combed along the direction of gas flow. The total pressure drop Δp F of the catalytic unit with a wall-flow substrate is the sum of the following five items: contraction the local resistance pressure drop Δp friction,in caused by the inlet pipe contraction, w the permeation pressure drop Δp friction,out caused by the filter wall, expand the local resistance pressure drop Δp F caused by the outlet pipe expansion. As mentioned above, the first and last items are relatively small and can be ignored, so Δp F can be calculated by the following formula.

[0163] Δp friction,in = Δp w + Δp friction,out

[0164] The total pressure drop of the catalytic unit with a wall-flow substrate:

[0165] The above describes the calculation method of the pressure drop Δp S of a catalytic unit with a straight-through substrate and the pressure drop Δp F of a catalytic unit with a wall-flow substrate. However, in actual diesel engine aftertreatment products, there may be more than one section of these two types of substrates. For example, in the aftertreatment system of a diesel engine at the China VI emission level, there is usually one section of DOC (straight-through), one section of DPF (wall-flow), and one or more sections of SCR / ASC (all straight-through). This section provides a calculation method for the total pressure drop of all catalytic units in a complete aftertreatment product.

[0166] Suppose there are m straight-through catalytic units and n wall-flow catalytic units in this set of aftertreatment products. Let Δp S,i i represent the pressure drop of the i-th straight-through catalytic unit among the m straight-through catalytic units, and let Δp F,j j represent the pressure drop of the j-th wall-flow catalytic unit among the n wall-flow catalytic units. Then the total pressure drop Δptotal The pressure drop of each catalytic unit can be calculated by the following formula.

[0167]

[0168] In addition, the pressure drop values of each catalytic unit calculated by the model can be compared with the actually measured pressure drop values of each catalytic unit, and the pressure drop prediction module is corrected and calibrated by adjusting the resistance coefficient, and the principle logic is as shown in Figure 2 Therefore, the method and the model have wide application conditions and can be applied to different diesel engine models, different engine steady state point working conditions and different aftertreatment systems.

[0169] Figure 2 The method is expressed in the form of formula as follows: the resistance coefficient β of the i-th straight-through carrier i And the resistance coefficient γ of the j-th wall-flow carrier j Instead of being directly set to 1 according to the above method, the actual pressure drop measurement results are combined to correct according to the least square method, so that the model has higher accuracy.

[0170]

[0171] Example two:

[0172] As shown in Figure 5 :

[0173] The present disclosure also provides a diesel engine aftertreatment unit pressure drop prediction method, comprising:

[0174] S201: Collecting diesel engine operating parameters and aftertreatment system parameters, wherein the operating parameters include: engine exhaust parameters, carrier parameters and catalyst coating parameters;

[0175] S202: Calculating the pressure drop of the straight-through carrier and the pressure drop of the wall-flow carrier by using the diesel engine operating parameters collected by the parameter collection module;

[0176] S203: Accumulating and summing the straight-through carrier pressure drop and the wall-flow carrier pressure drop calculated by the carrier pressure drop calculation module to obtain the total pressure drop of the diesel engine aftertreatment unit as a prediction result.

[0177] Specifically, the straight-through carrier pressure drop of the catalytic unit with a straight-through carrier is calculated by the following formula:

[0178]

[0179] Wherein,

[0180] Wherein, a = a0-2a c ;

[0181] wherein a0 is obtained by the following formula: (a0+w) 2 CPSM = 1 ;

[0182] In the formula, Δp S and Δp contraction represents the pressure drop caused by the local resistance of the pipeline contraction when the gas flows to the inlet of the catalytic unit, i.e. the straight-through carrier pressure drop;

[0183] ξ is the expansion and contraction resistance coefficient of the inlet and outlet pipeline;

[0184] ρ is the density of the gas flow;

[0185] u in is the velocity of the engine exhaust gas flowing into the carrier channel;

[0186] CPSM is the number of channels per square meter of the end face circle of the carrier, which is obtained by the carrier parameter collected by the parameter collection module;

[0187] Q V is the volume flow of the engine exhaust gas, which is obtained by the engine exhaust gas parameter collected by the parameter collection module;

[0188] D is the diameter of the catalytic unit, which is obtained by the carrier parameter collected by the parameter collection module;

[0189] a is the side length of the channel in the catalytic unit;

[0190] a0 is the side length of the channel possessed by the carrier itself in the catalytic unit, and

[0191] a c is the coating thickness of the catalyst coating in the catalytic unit, which is obtained by the catalyst coating parameter collected by the parameter collection module;

[0192] w is the wall thickness value possessed by the carrier itself in the catalytic unit, which is obtained by the carrier parameter collected by the parameter collection module.

[0193] Further, the wall flow carrier pressure drop of the catalytic unit with the wall flow carrier is calculated by the following formula:

[0194] Δp F = Δp friction,in + Δp w + Δp friction,out ; wherein,

[0195]

[0196] wherein,

[0197]

[0198]

[0199]

[0200] Δp friction,in represents the pressure drop caused by the frictional shear stress of the gas flow along the inlet channel of the wall-flow catalytic unit;

[0201] Δp friction,out represents the pressure drop caused by the frictional shear stress of the gas flow along the outlet channel of the wall-flow catalytic unit;

[0202] Δp w represents the pressure drop caused by the permeation of the gas through the filter wall of the wall-flow carrier;

[0203] f represents the frictional resistance coefficient along the channel;

[0204] μ represents the viscosity of the gas flow;

[0205] T represents the temperature of the engine exhaust, which is obtained by the engine exhaust parameter collected by the parameter collection module;

[0206] L represents the length of the catalytic unit carrier, which is obtained by the carrier parameter collected by the parameter collection module;

[0207] cdr represents the asymmetry ratio of the wall-flow carrier, which is equal to the ratio of the inlet / outlet channel side length, and is obtained by the carrier parameter collected by the parameter collection module;

[0208] u w0 represents the average flow velocity of the gas flow through the filter wall of the wall-flow carrier;

[0209] k represents the permeability of the filter wall of the wall-flow carrier;

[0210] d pore represents the pore size of the micropore of the filter wall of the wall-flow carrier, which is obtained by the carrier parameter collected by the parameter collection module;

[0211] ε represents the porosity of the micropore of the filter wall of the wall-flow carrier, which is obtained by the carrier parameter collected by the parameter collection module.

[0212] Further, the total pressure drop of the diesel engine aftertreatment unit is calculated as a prediction result by the following formula:

[0213]

[0214] wherein Δp total represents the total pressure drop of all catalytic units of the entire aftertreatment system;

[0215] Δp S,iThis represents the pressure drop across the catalytic unit of the i-th through-support;

[0216] Δp F,j This represents the wall-flow support pressure drop of the catalytic unit of the j-th wall-flow support;

[0217] i and j are positive integers; m is the number of catalytic units in the straight-through support; n is the number of catalytic units in the wall-flow support.

[0218] Furthermore, the method also includes: comparing the calculated pressure drop value of each catalytic unit with the actual measured pressure drop value of each catalytic unit, and correcting and calibrating the pressure drop prediction module by adjusting the drag coefficient.

[0219] Specifically, correction and calibration are performed using the following formula:

[0220]

[0221] β i This represents the drag coefficient of the i-th straight-through catalytic unit;

[0222] γ j This represents the drag coefficient of the j-th wall-flow catalytic unit.

[0223] Example 3:

[0224] This disclosure also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described diesel engine aftertreatment unit pressure drop prediction method.

[0225] Figure 6 This is a schematic diagram of the internal structure of an electronic device in one embodiment. For example... Figure 6 As shown, the electronic device includes a processor, a storage medium, a memory, and a network interface connected via a system bus. The storage medium stores an operating system, a database, and computer-readable instructions. The database may store a sequence of control information. When executed by the processor, the computer-readable instructions cause the processor to implement a method. The processor provides computing and control capabilities, supporting the operation of the entire computer device. The memory stores computer-readable instructions, which, when executed by the processor, cause the processor to perform a method. The network interface of the computer device is used for communication with a terminal. Those skilled in the art will understand that… Figure 6The structure shown in the figure is only a block diagram of part of the structure related to the scheme of the present application, and does not constitute a limitation on the computer device to which the scheme of the present application is applied. The specific computer device can include more or fewer components than those shown in the figure, or combine certain components, or have a different component arrangement.

[0226] The electronic device includes, but is not limited to, a smart phone, a computer, a tablet computer, a wearable smart device, an artificial intelligence device, a mobile power supply, etc.

[0227] The processor can be composed of integrated circuits in some embodiments, for example, can be composed of a single packaged integrated circuit, or can be composed of multiple packaged integrated circuits with the same function or different functions, including one or more combinations of central processing units (CPUs), microprocessors, digital processing chips, graphics processors, and various control chips. The processor is the control core (Control Unit) of the electronic device, which connects various components of the entire electronic device through various interfaces and lines, executes programs or modules stored in the memory (such as executing remote data read-write programs, etc.), and calls data stored in the memory to execute various functions and process data of the electronic device.

[0228] The bus can be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. The bus is configured to realize the connection and communication between the memory, the at least one processor, etc.

[0229] Figure 6 Only the electronic device with components is shown, and those skilled in the art can understand that, Figure 6 The structure shown does not constitute a limitation on the electronic device, and can include fewer or more components than those shown in the figure, or combine certain components, or have a different component arrangement.

[0230] For example, although not shown, the electronic device can further include a power supply (such as a battery) to supply power to each component, and preferably, the power supply can be connected to the at least one processor logic through a power management device, so that the power management device can implement functions such as charge management, discharge management, and power consumption management. The power supply can also include one or more DC or AC power sources, recharging devices, power failure detection circuits, power converters or inverters, power status indicators, and the like. The electronic device can also include various sensors, Bluetooth modules, Wi-Fi modules, and the like, which are not described here.

[0231] Further, the electronic device can further include a network interface, which can optionally include a wired interface and / or a wireless interface (such as a WI-FI interface, a Bluetooth interface, etc.), and is generally used to establish a communication connection between the electronic device and other electronic devices.

[0232] Optionally, the electronic device can further include a user interface, which can be a display (Display), an input unit (such as a keyboard (Keyboard)), and optionally, the user interface can also be a standard wired interface, a wireless interface. Optionally, in some embodiments, the display can be an LED display, a liquid crystal display, a touch liquid crystal display, and an OLED (Organic Light-Emitting Diode) touch, etc. The display can also be appropriately referred to as a display screen or a display unit, and is used to display information processed in the electronic device and to display a visualized user interface.

[0233] Further, the computer usable storage medium can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, at least one application required by a function, etc.; and the data storage area can store data created according to the use of the blockchain node, etc.

[0234] In several embodiments provided by the present application, it should be understood that the disclosed devices, apparatuses and methods can be implemented in other ways. For example, the above-described device embodiments are merely illustrative, and for example, the division of the modules is only a logical function division, and actual implementation can have another division manner.

[0235] The modules described as separate components can or can not be physically separated, and the components shown as modules can or can not be physical units, i.e., they can be located in one place, or can be distributed on multiple network units. Part or all of the modules can be selected according to actual needs to achieve the purpose of the present embodiment.

[0236] In addition, each function module in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of hardware plus software function module.

[0237] The above describes the embodiments of the present disclosure. However, these embodiments are only for illustrative purposes, and are not intended to limit the scope of the present disclosure. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A diesel engine aftertreatment unit pressure drop prediction system, characterized in that, include: The parameter acquisition module is used to acquire diesel engine operating parameters and after-treatment system parameters, wherein the operating parameters include: engine exhaust parameters, carrier parameters and catalyst coating parameters; The carrier pressure drop calculation module is used to calculate the pressure drop of the straight-through carrier and the pressure drop of the wall-flow carrier using the diesel engine operating parameters collected by the parameter acquisition module. The pressure drop prediction module is used to sum the pressure drop of the straight-through carrier and the pressure drop of the wall-flow carrier calculated by the carrier pressure drop calculation module to obtain the total pressure drop of the diesel engine aftertreatment unit as the prediction result. The carrier pressure drop calculation module is specifically used for: The pressure drop of the straight-through support in a catalytic unit with a straight-through support is calculated using the following formula: ； in, ; in, ; in, The following formula can be used to obtain: ; In the formula, and This refers to the pressure drop caused by the local resistance resulting from the narrowing of the pipeline when the gas flows to the inlet of the catalytic unit, i.e., the pressure drop of the direct-flow carrier. The expansion and contraction resistance coefficient of the inlet and outlet pipelines; The density of the airflow; The speed at which engine exhaust flows into the carrier channel; The number of channels per square meter on the end face of the carrier is obtained through the carrier parameters collected by the parameter acquisition module; The volumetric flow rate of the engine exhaust is obtained by collecting engine exhaust parameters through the parameter acquisition module. The diameter of the catalytic unit is obtained from the carrier parameters acquired by the parameter acquisition module; Let be the side length of the channel in the catalytic unit; Let be the side length of the channel inherent in the support within the catalytic unit, and . The coating thickness of the catalyst coating in the catalytic unit is obtained by acquiring catalyst coating parameters through the parameter acquisition module; The wall thickness value of the support itself in the catalytic unit is obtained through the support parameters acquired by the parameter acquisition module.

2. The system according to claim 1, characterized in that, The carrier pressure drop calculation module is specifically used for: The pressure drop of the wall-flow support in the catalytic unit with the wall-flow support is calculated using the following formula. : ;in, ； ； ； in, ； ； ； This represents the pressure drop caused by frictional shear stress along the airflow path in the intake channel of a wall-flow catalytic converter. This represents the pressure drop caused by frictional shear stress along the airflow path in the outlet channel of a wall-flow catalytic converter. This represents the pressure drop that occurs when gas permeates through the filter wall of a wall-flow carrier. This represents the frictional resistance coefficient along the friction path; Indicates the viscosity of the airflow; The temperature of the engine exhaust is obtained from the engine exhaust parameters collected by the parameter acquisition module. The length of the catalytic unit support is obtained through the support parameters acquired by the parameter acquisition module; The asymmetry ratio of the wall-flow carrier is equal to the ratio of the inlet / outlet channel side lengths, and is obtained through the carrier parameters acquired by the parameter acquisition module. This represents the average velocity of the airflow as it passes through the filter wall of a wall-flow carrier. This indicates the permeability of the filter wall in a wall-flow carrier. The pore size of the micropores in the filter wall of the wall-flow carrier is obtained from the carrier parameters acquired by the parameter acquisition module. The porosity of the micropores in the filter wall of the wall-flow carrier is obtained from the carrier parameters acquired by the parameter acquisition module.

3. The system according to claim 2, characterized in that, The pressure drop prediction module specifically calculates the total pressure drop of the diesel engine aftertreatment unit as the prediction result using the following formula: ； in, This indicates the total pressure drop across all catalytic converters in the diesel engine's aftertreatment unit; Indicates the first Pressure drop of the catalytic unit on the straight-through support; Indicates the first The pressure drop of the catalytic unit on the wall-flow support; m represents the number of catalytic units on the straight-through support; n represents the number of catalytic units on the wall-flow support.

4. The system according to claim 3, characterized in that, The system also includes: The correction and calibration module is used to compare the calculated pressure drop value of each catalytic unit with the actual measured pressure drop value of each catalytic unit, and to correct and calibrate the pressure drop prediction module by adjusting the drag coefficient.

5. The system according to claim 4, characterized in that, The correction and calibration module specifically performs correction and calibration using the following formula: ； Indicates the first The drag coefficient of a single-pass catalytic unit; Indicates the first The drag coefficient of each wall-flow catalytic unit.

6. A method for predicting the pressure drop of a diesel engine aftertreatment unit, characterized in that, include: Collect diesel engine operating parameters and after-treatment system parameters, wherein the operating parameters include: engine exhaust parameters, carrier parameters and catalyst coating parameters; The pressure drop of the straight-through carrier and the pressure drop of the wall-flow carrier are calculated using the diesel engine operating parameters collected by the parameter acquisition module. The total pressure drop of the diesel engine aftertreatment unit is obtained by summing the pressure drop of the straight-through carrier and the pressure drop of the wall-flow carrier calculated by the carrier pressure drop calculation module as the prediction result. The pressure drop of the straight-through support in a catalytic unit with a straight-through support is calculated using the following formula: ； in, ; in, ; in, The following formula can be used to obtain: ; In the formula, and This refers to the pressure drop caused by the local resistance resulting from the narrowing of the pipeline when the gas flows to the inlet of the catalytic unit, i.e., the pressure drop of the direct-flow carrier. The expansion and contraction resistance coefficient of the inlet and outlet pipelines; The density of the airflow; The speed at which engine exhaust flows into the carrier channel; The number of channels per square meter on the end face of the carrier is obtained through the carrier parameters collected by the parameter acquisition module; The volumetric flow rate of the engine exhaust is obtained by collecting engine exhaust parameters through the parameter acquisition module. The diameter of the catalytic unit is obtained from the carrier parameters acquired by the parameter acquisition module; Let be the side length of the channel in the catalytic unit; Let be the side length of the channel inherent in the support within the catalytic unit, and . The coating thickness of the catalyst coating in the catalytic unit is obtained by acquiring catalyst coating parameters through the parameter acquisition module; The wall thickness value of the support itself in the catalytic unit is obtained through the support parameters acquired by the parameter acquisition module.

7. The method according to claim 6, characterized in that, The method further includes: comparing the calculated pressure drop value of each catalytic unit with the actual measured pressure drop value of each catalytic unit, and correcting and calibrating the pressure drop prediction module by adjusting the drag coefficient.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes a computer program, it implements the steps of the diesel engine aftertreatment unit pressure drop prediction method as described in any one of claims 6 or 7.

9. A diesel locomotive, characterized in that, It is equipped with the electronic equipment as described in claim 8 and the diesel engine aftertreatment unit pressure drop prediction system as described in any one of claims 1 to 5.

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