Diesel engine rapid cold start electric glow plug design method and system

Abstract

The invention discloses a diesel engine rapid cold start electric glow plug design method and system. The method comprises the steps that electric glow plug design parameters are selected; obtaining electric glow plug performance parameters according to the electric glow plug design parameters; and carrying out multi-objective optimization on performance parameters of the electric glow plug by adopting a non-dominated sorting genetic algorithm to obtain a design scheme that the total heating time consumption of the electric glow plug and the space volume occupied by the electric glow plug are optimal when the ignition point in the cylinder is reached and the constraint conditions are met. By the adoption of the technical scheme, optimization of the electric glow plug for rapid cold start of the diesel engine is achieved, the number of tests is greatly reduced, and the design efficiency and benefits of the electric glow plug are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of diesel engine intake air heating, and in particular relates to a design method and system for a diesel engine rapid cold start electric glow plug. Background Art

[0002] my country is a vast country with a wide north-south latitude span. Some provinces in Northeast and Northwest my country often experience extreme winter weather, with average temperatures dropping below -10°C in many areas. The average temperature in the coldest month in Xinjiang, Inner Mongolia, Tibet, and Northeast China ranges from -41°C to -25°C, with the lowest point in Mohe, Heilongjiang, reaching -53°C. In these extremely cold conditions, diesel engine intake temperatures can be excessively low, leading to ignition difficulties and delayed combustion, which severely restricts vehicle mobility.

[0003] As a widely used method for heating diesel engine intake air, electric heating technology heats the intake duct via a resistance wire or other electric heating element, achieving rapid preheating of the diesel engine's intake air and improving fuel atomization and evaporation conditions, thereby ensuring rapid ignition and stable combustion. However, due to the long-standing reliance on traditional electric glow plug optimization design methods based on trial and error, electric heating devices face urgent bottlenecks: heating power mismatch, low heat transfer efficiency, non-compact structural design, high redundancy, and low reliability. Therefore, combining transient heat flow numerical simulation methods, neural network models, and automatic optimization theory to develop a new design method for electric glow plugs for rapid cold starts in diesel engines is crucial for developing a highly efficient, reliable, and compact electric heating device, thereby enabling rapid diesel engine starts in extremely cold environments and improving vehicle maneuverability. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a design method and system for a diesel engine rapid cold start electric glow plug.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A design method for a diesel engine rapid cold start electric glow plug, comprising:

[0007] Select the design parameters of the electric glow plug;

[0008] According to the design parameters of the electric glow plug, the performance parameters of the electric glow plug are obtained;

[0009] The non-dominated sorting genetic algorithm is used to perform multi-objective optimization of the performance parameters of the electric preheating plug, and the optimal design scheme for the total heating time of the electric preheating plug and the space volume occupied by the electric preheating plug when the cylinder reaches the ignition point is obtained while meeting the constraints.

[0010] Preferably, the design parameters of the electric glow plug include: the diameter of the resistance wire coil, the pitch of the resistance wire coil, the length of the electric glow plug, the diameter of the electric glow plug, and the heat power per unit area of ​​the electric glow plug;

[0011] Preferably, the performance parameters of the glow plug include: total glow plug heating power, volume occupied by the glow plug, and total glow plug heating time when the cylinder reaches the ignition point. The total glow plug heating time when the cylinder reaches the ignition point is evaluated using transient heat flow numerical simulation. Based on the simulation results, an optimal Latin hypercube sampling method and a generalized neural network are used to construct a mapping relationship between the total glow plug heating time when the cylinder reaches the ignition point and the resistance wire coil diameter, resistance wire coil pitch, glow plug length, glow plug diameter, and glow plug thermal power per unit area. This allows for rapid estimation of the total glow plug heating time when the cylinder reaches the ignition point based on the glow plug design parameters.

[0012] Preferably, the constraint condition is: the total heating power of the electric preheating plug is less than a given value, and the objective function is: minimizing the total heating time of the electric preheating plug when the cylinder reaches the ignition point and minimizing the space volume occupied by the electric preheating plug.

[0013] The present invention also provides a diesel engine rapid cold start electric glow plug design system, comprising:

[0014] The first processing module is used to select the design parameters of the electric glow plug;

[0015] A second processing module is used to obtain the performance parameters of the electric glow plug according to the design parameters of the electric glow plug;

[0016] The third processing module is used to perform multi-objective optimization of the performance parameters of the electric preheating plug using a non-dominated sorting genetic algorithm to obtain an optimal design solution for the total heating time of the electric preheating plug and the spatial volume occupied by the electric preheating plug when the ignition point is reached in the cylinder, which meets the constraints.

[0017] Preferably, the first processing module includes:

[0018] The design parameters of the electric preheating plug include: the diameter of the resistance wire coil, the pitch of the resistance wire coil, the length of the electric preheating plug, the diameter of the electric preheating plug, and the heat power per unit area of ​​the electric preheating plug;

[0019] Preferably, the second processing module includes:

[0020] The first processing unit is used to obtain performance parameters of the electric preheating plug, including: total heating power of the electric preheating plug, volume of space occupied by the electric preheating plug, and total heating time of the electric preheating plug when the cylinder reaches the ignition point.

[0021] The second processing unit evaluates the total heating time of the electric preheating plug when the cylinder reaches the ignition point through a transient heat flow numerical simulation method. Based on the numerical simulation results, the optimal Latin hypercube sampling method and a generalized neural network are used to construct a mapping relationship between the total heating time of the electric preheating plug when the cylinder reaches the ignition point and the resistance wire coil diameter, resistance wire coil pitch, electric preheating plug length, electric preheating plug diameter, and electric preheating plug thermal power per unit area. This enables rapid evaluation of the total heating time of the electric preheating plug when the cylinder reaches the ignition point based on the design parameters of the electric preheating plug.

[0022] Preferably, in the third module:

[0023] The constraint condition is that the total heating power of the electric preheating plug is less than a given value, and the objective function is to minimize the total heating time of the electric preheating plug when the cylinder reaches the ignition point and minimize the space volume occupied by the electric preheating plug.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention constructs a numerical calculation model for the intake air heating of electric preheating plugs by considering physical processes such as spraying, mixing, combustion, and heat transfer. This model enables accurate evaluation of the intake air heating performance of electric preheating plugs, significantly reduces the number of tests, and improves the efficiency and effectiveness of the evaluation of electric preheating plug design schemes.

[0026] 2. The present invention introduces a numerical calculation model for intake air heating of electric preheating plugs, an optimal Latin hypercube sampling method, a generalized neural network agent model, and a non-dominated sorting genetic optimization algorithm into the optimization design of electric preheating plugs, thereby realizing multi-objective optimization of electric preheating plugs, breaking the limitations of traditional optimization methods based on manual trial and error, and greatly improving optimization efficiency and accuracy.

[0027] 3. The present invention takes the total heating power of the electric preheating plug as the optimization constraint, ensuring the economy and reliability of the optimization scheme; introduces the volume of the electric preheating plug into the optimization target, effectively balancing the heating efficiency and structural compactness of the electric preheating plug. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0029] Figure 1 This is a flow chart of a method for designing a diesel engine rapid cold start electric glow plug according to an embodiment of the present invention;

[0030] Figure 2 This is a geometric diagram of the electric glow plug model in the example. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0032] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Example 1:

[0034] like Figure 1 As shown, an embodiment of the present invention provides a method for designing a diesel engine rapid cold start electric glow plug, comprising:

[0035] (1) Select the design parameters of the electric preheating plug: the diameter of the resistance wire coil d, the pitch of the resistance wire coil l, the length of the electric preheating plug L, the diameter of the electric preheating plug D, and the heating power per unit area of ​​the electric preheating plug w;

[0036] (2) Select the performance parameters of the glow plug: the total heating power P of the glow plug, the volume V occupied by the glow plug, and the total heating time t when the cylinder reaches the ignition point;

[0037] (3) The calculation formula of the total heating power P of the electric preheating plug is P = wS, where is the surface area of ​​the electric glow plug;

[0038] (4) The calculation formula for the space volume V occupied by the electric preheating plug is:

[0039] (5) The total heating time t of the electric preheating plug when the cylinder reaches the ignition point is evaluated by transient heat flow numerical simulation method; by simulating the transient process of electric preheating plug heating, the temperature of the oil-gas mixture in the cylinder is monitored, and the total heating time of the electric preheating plug when the cylinder reaches the ignition point is calculated; the calculation domain of the transient heat flow numerical simulation method is the fluid domain composed of geometric structures such as the intake and exhaust duct, electric preheating plug, intake and exhaust valve, nozzle, and cylinder. The inlet boundary condition is the velocity-temperature condition, the outlet boundary condition is the pressure boundary condition, the electric preheating plug wall adopts the given unit area heat power condition, the calculation domain is discretized by unstructured grid, the numerical simulation adopts the unsteady Reynolds average method, the Navier-Stokes equations and energy equations are discretized based on the finite volume method, the turbulence model adopts the RNG (Renormalization Group Theory) k-ε model, and the spray atomization model adopts the KH-RT (Kelvin Helmholtz-Rayleigh Taylor model, the non-time counter model is used for droplet collision and aggregation model, the Wall-Film model and O'Rourke-Amsdenm model are used for droplet impact model, the SAGE model is used for combustion model, the second-order central difference format is used for spatial discretization, and the first-order upwind format is used for temporal discretization;

[0040] (6) Considering that the computational complexity of using the transient heat flow numerical simulation method to evaluate the total heating time t of the electric preheating plug when the cylinder reaches the ignition point is very large, a mapping relationship between the total heating time t of the electric preheating plug when the cylinder reaches the ignition point and the design parameters (resistance wire coil diameter d, resistance wire coil pitch l, electric preheating plug length L, electric preheating plug diameter D, electric preheating plug unit area thermal power w) is further established, so as to quickly evaluate the total heating time t of the electric preheating plug when the cylinder reaches the ignition point. The specific process is as follows:

[0041] I) for the five design parameters in step (1): the resistance wire coil diameter d, the resistance wire coil pitch l, the electric preheating plug length L, the electric preheating plug diameter D, and the electric preheating plug unit area thermal power w, given a value range for each design parameter, within the value range of the design parameter, using the optimal Latin hypercube sampling method to generate a sample set, the number of sample sets is (n+1)×(n+2) / 2 times the number of design parameters, where n is the number of design parameters, and ultimately forming (n+1)×(n+2) / 2 design schemes;

[0042] II) For each design scheme in the sample set in process I), use step (5) to evaluate the total heating time t of the electric preheating plug when the cylinder reaches the ignition point;

[0043] III) Based on a generalized neural network (GRNN), a mapping relationship is constructed between the total heating time t of the electric preheating plug when the cylinder reaches the ignition point and the design parameters (resistance wire coil diameter d, resistance wire coil pitch l, electric preheating plug length L, electric preheating plug diameter D, and electric preheating plug thermal power per unit area w). The mapping expression is: t = f(d, l, L, D, w), where f is the function symbol. This allows for rapid estimation of the total heating time t of the electric preheating plug when the cylinder reaches the ignition point.

[0044] (7) A non-dominated sorting genetic algorithm (NSGA-Ⅱ) is used to implement multi-objective optimization of the performance parameters of the electric preheating plug. The constraint condition is that the total heating power P of the electric preheating plug is less than a given value. The objective function is to minimize the total heating time t of the electric preheating plug when the cylinder reaches the ignition point and minimize the space volume V occupied by the electric preheating plug. During the optimization process, the total heating power P of the electric preheating plug is calculated by step (3), the space volume V occupied by the electric preheating plug is calculated by step (4), and the total heating time t of the electric preheating plug when the cylinder reaches the ignition point is quickly evaluated by process III) in step (6). Finally, a design scheme with better total heating time t and space volume V occupied by the electric preheating plug when the cylinder reaches the ignition point is obtained under the constraint condition (the total heating power P of the electric preheating plug is less than a given value).

[0045] Example 1:

[0046] (1) This embodiment is aimed at a certain type of air-cooled diesel engine with an electric glow plug. The geometric model is shown in the attached figure. Figure 2 As shown, the design parameters and performance parameters of the model are selected by referring to steps (1) and (2);

[0047] (2) The total heating power P of the electric preheating plug of this model is calculated using the formula in step (3), and the volume V of the space occupied by the electric preheating plug is calculated using the formula in step (4);

[0048] (3) To obtain the total heating time t of the electric preheating plug when the cylinder reaches the ignition point, a transient heat flow numerical model of the electric preheating plug intake heating is constructed according to step (5);

[0049] (4) In order to quickly evaluate the total heating time t of the electric preheating plug when the cylinder reaches the ignition point, first, the method introduced in process I in step (6) is used to generate 50 samples in the design space, which can ensure that the sample points are evenly distributed in the design space. Then, according to process II in step (6), the total heating time t of the electric preheating plug when the cylinder reaches the ignition point is obtained for each sample. Finally, according to process III in step (6), a generalized neural network (GRNN) proxy model is constructed to obtain the mapping relationship between the total heating time t of the electric preheating plug when the cylinder reaches the ignition point and the design parameters. The cross-validation method is used to check the accuracy of the proxy model. The predicted values ​​of the performance parameters are in good agreement with the calculated values, and the root mean square error (RMSE) is less than 0.1. It can be considered that the proxy model in this example has a high mapping accuracy and can be used for subsequent optimization;

[0050] (5) A non-dominated sorting genetic algorithm (NSGA-Ⅱ) is used to implement multi-objective optimization of the electric preheating plug. The constraint condition is that the total heating power P of the electric preheating plug is less than a given value. The objective function is to minimize the total heating time t of the electric preheating plug when the cylinder reaches the ignition point and minimize the space volume V occupied by the electric preheating plug. During the optimization process, the total heating power P of the electric preheating plug is calculated by step (3), and the space volume V occupied by the electric preheating plug is calculated by step (4). The total heating time t of the electric preheating plug when the cylinder reaches the ignition point is obtained by the constructed proxy model. After optimization, the Pareto frontier solution set is obtained. The design scheme in the solution set is numerically simulated and verified. Finally, the optimal design scheme of the total heating time t of the electric preheating plug when the cylinder reaches the ignition point and the space volume V occupied by the electric preheating plug that meets the constraint conditions is obtained.

[0051] (6) The optimal glow plug design was processed and tested for low-temperature diesel engine starting. This experiment was conducted in a low-temperature environment test chamber at three temperatures: -20°C, -43°C, and -50°C. The measured variable was the total heating time t of the glow plug until the cylinder reached the ignition point. As shown in Table 1, the test results all showed successful ignition, and the total heating time t of the glow plug until the cylinder reached the ignition point met the design specifications at all test temperatures.

[0052] Table 1

[0053]

[0054] Example 2:

[0055] The embodiment of the present invention further provides a diesel engine rapid cold start electric glow plug design system, comprising:

[0056] The first processing module is used to select the design parameters of the electric glow plug;

[0057] A second processing module is used to obtain the performance parameters of the electric glow plug according to the design parameters of the electric glow plug;

[0058] The third processing module is used to perform multi-objective optimization of the performance parameters of the electric preheating plug using a non-dominated sorting genetic algorithm to obtain an optimal design solution for the total heating time of the electric preheating plug and the spatial volume occupied by the electric preheating plug when the ignition point is reached in the cylinder, which meets the constraints.

[0059] As an implementation of an embodiment of the present invention, the design parameters of the electric glow plug include: resistance wire coil diameter, resistance wire coil pitch, electric glow plug length, electric glow plug diameter, and electric glow plug thermal power per unit area.

[0060] As an implementation manner of an embodiment of the present invention, the second processing module includes:

[0061] The first processing unit is used to obtain performance parameters of the electric preheating plug, including: total heating power of the electric preheating plug, volume of space occupied by the electric preheating plug, and total heating time of the electric preheating plug when the cylinder reaches the ignition point.

[0062] The second processing unit evaluates the total heating time of the electric preheating plug when the cylinder reaches the ignition point through a transient heat flow numerical simulation method. Based on the numerical simulation results, the optimal Latin hypercube sampling method and a generalized neural network are used to construct a mapping relationship between the total heating time of the electric preheating plug when the cylinder reaches the ignition point and the resistance wire coil diameter, resistance wire coil pitch, electric preheating plug length, electric preheating plug diameter, and electric preheating plug thermal power per unit area. This enables rapid evaluation of the total heating time of the electric preheating plug when the cylinder reaches the ignition point based on the design parameters of the electric preheating plug.

[0063] As an implementation method of an embodiment of the present invention, the constraint condition is: the total heating power of the electric preheating plug is less than a given value, and the objective function is: minimizing the total heating time of the electric preheating plug when the cylinder reaches the ignition point and minimizing the space volume occupied by the electric preheating plug.

[0064] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A design method for a diesel engine rapid cold start electric glow plug, characterized in that: include: Select the design parameters of the electric glow plug; According to the design parameters of the electric glow plug, the performance parameters of the electric glow plug are obtained; The non-dominated sorting genetic algorithm is used to perform multi-objective optimization of the performance parameters of the electric preheating plug, and the optimal design scheme for the total heating time of the electric preheating plug and the space volume occupied by the electric preheating plug when the cylinder reaches the ignition point is obtained while meeting the constraints.

2. The diesel engine rapid cold start electric glow plug design method according to claim 1, characterized in that: The design parameters of the electric preheating plug include: the diameter of the resistance wire coil, the pitch of the resistance wire coil, the length of the electric preheating plug, the diameter of the electric preheating plug, and the thermal power per unit area of ​​the electric preheating plug.

3. The diesel engine rapid cold start electric glow plug design method according to claim 2, characterized in that: Glow plug performance parameters include total glow plug heating power, volume occupied by the glow plug, and total heating time until the cylinder reaches the ignition point. Transient heat flow numerical simulations are used to evaluate this total heating time. Based on these simulation results, an optimal Latin hypercube sampling method and a generalized neural network are used to map this total heating time to the resistance wire coil diameter, resistance wire coil pitch, glow plug length, glow plug diameter, and glow plug thermal power per unit area. This allows for rapid estimation of the total heating time until the cylinder reaches the ignition point based on the glow plug's design parameters.

4. The diesel engine rapid cold start electric glow plug design method according to claim 3, characterized in that: The constraint condition is that the total heating power of the electric preheating plug is less than a given value, and the objective function is to minimize the total heating time of the electric preheating plug when the cylinder reaches the ignition point and minimize the space volume occupied by the electric preheating plug.

5. A diesel engine rapid cold start electric preheating plug design system, characterized in that: include: The first processing module is used to select the design parameters of the electric glow plug; A second processing module is used to obtain the performance parameters of the electric glow plug according to the design parameters of the electric glow plug; The third processing module is used to perform multi-objective optimization of the performance parameters of the electric preheating plug using a non-dominated sorting genetic algorithm to obtain an optimal design solution for the total heating time of the electric preheating plug and the spatial volume occupied by the electric preheating plug when the ignition point is reached in the cylinder, which meets the constraints.

6. The diesel engine rapid cold start electric glow plug design system according to claim 5, characterized in that: The first processing module is used to select the design parameters of the electric preheating plug, which include: the diameter of the resistance wire coil, the pitch of the resistance wire coil, the length of the electric preheating plug, the diameter of the electric preheating plug, and the thermal power per unit area of ​​the electric preheating plug.

7. The diesel engine rapid cold start electric glow plug design system according to claim 6, characterized in that: The second processing module includes: The first processing unit is used to obtain performance parameters of the electric preheating plug, including: total heating power of the electric preheating plug, volume of space occupied by the electric preheating plug, and total heating time of the electric preheating plug when the cylinder reaches the ignition point. The second processing unit evaluates the total heating time of the electric preheating plug when the cylinder reaches the ignition point through a transient heat flow numerical simulation method. Based on the numerical simulation results, the optimal Latin hypercube sampling method and a generalized neural network are used to construct a mapping relationship between the total heating time of the electric preheating plug when the cylinder reaches the ignition point and the resistance wire coil diameter, resistance wire coil pitch, electric preheating plug length, electric preheating plug diameter, and electric preheating plug thermal power per unit area. This enables rapid evaluation of the total heating time of the electric preheating plug when the cylinder reaches the ignition point based on the design parameters of the electric preheating plug.

8. The diesel engine rapid cold start electric glow plug design system according to claim 7, characterized in that: The third processing module uses a non-dominated sorting genetic algorithm to perform multi-objective optimization of the glow plug's performance parameters. The constraints are: the total glow plug power is less than a given value. The objective functions are: minimizing the total heating time required to reach the ignition point in the cylinder and minimizing the volume occupied by the glow plug.

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