Design method and system for fast cold start electric preheating of diesel engine

Abstract

The application discloses a design method and system of a diesel engine quick cold start electric preheating plug, and comprises the following steps: selecting electric preheating plug design parameters; obtaining electric preheating plug performance parameters according to the electric preheating plug design parameters; performing multi-objective optimization on the electric preheating plug performance parameters by using a non-dominated sorting genetic algorithm to obtain a design scheme that meets constraint conditions and is optimal in terms of total heating time of the electric preheating plug when the cylinder reaches an ignition point and a space volume occupied by the electric preheating plug. By using the technical scheme, optimization of the diesel engine quick cold start electric preheating plug is realized, the number of tests is greatly reduced, and the design efficiency and benefits of the electric preheating plug are improved.

Description

Technical Field

[0001] This invention belongs to the field of diesel engine intake air heating technology, and particularly relates to a design method and system for a diesel engine fast cold start electric glow plug. Background Technology

[0002] my country has a vast territory with a wide latitudinal span. Some provinces in the Northeast and Northwest frequently experience extreme weather in winter, with average winter temperatures in many areas below -10℃. In Xinjiang, Inner Mongolia, Tibet, and the Northeast, the average temperature of the coldest month ranges from -41℃ to -25℃, and the lowest temperature in Mohe, Heilongjiang Province, can even reach -53℃. In extremely cold environments, the intake temperature of diesel engines is too low, leading to problems such as difficulty in ignition and delayed combustion, which severely restricts vehicle maneuverability.

[0003] As a widely used method for heating intake air in diesel engines, electric heating technology heats the intake manifold using resistance wires or other electric heating elements, achieving rapid preheating of the intake air and improving fuel atomization and evaporation conditions, thereby ensuring rapid ignition and stable combustion in the diesel engine. However, due to the long-term reliance on traditional electric glow plug optimization design methods based primarily on manual trial and error, electric heating devices face bottlenecks that urgently need to be overcome: mismatched heating power, low heat exchange efficiency, non-compact structural design, high redundancy, and low reliability. Therefore, combining transient heat flux numerical simulation methods, neural network models, and automatic optimization theory, developing a new design method for diesel engine rapid cold start electric glow plugs is crucial for developing high-efficiency, high-reliability, and compact electric heating devices, thereby achieving rapid starting of diesel engines in extremely cold environments and improving vehicle mobility. 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 fast cold start electric glow plug for a diesel engine.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

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

[0007] Select the design parameters for the electric preheating plug;

[0008] Based on the design parameters of the electric preheating plug, the performance parameters of the electric preheating plug are obtained;

[0009] A non-dominated sorting genetic algorithm was used to optimize the performance parameters of the electric glow plug for multiple objectives, resulting in a design scheme that satisfies the constraints of the optimal total heating time of the electric glow plug when the cylinder reaches the ignition point and the optimal space volume occupied by the electric glow plug.

[0010] As a preferred option, the design parameters of the electric preheating plug include: resistance wire coil diameter, resistance wire coil pitch, electric preheating plug length, electric preheating plug diameter, and electric preheating plug heat power per unit area.

[0011] Preferably, the performance parameters of the electric glow plug include: the total heating power of the electric glow plug, the volume occupied by the electric glow plug, and the total heating time of the electric glow plug when the cylinder reaches the ignition point. Specifically, the total heating time of the electric glow plug when the cylinder reaches the ignition point is evaluated using a transient heat flux numerical simulation method. Based on the numerical simulation results, an 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 glow plug when the cylinder reaches the ignition point and 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. This allows for rapid evaluation of the total heating time of the electric glow plug when the cylinder reaches the ignition point based on the electric glow plug design parameters.

[0012] As a preferred option, the constraints are: the total heating power of the electric glow plug is less than a given value, and the objective functions are: to minimize the total heating time of the electric glow plug when the cylinder reaches the ignition point and to minimize the space volume occupied by the electric glow plug.

[0013] This invention also provides a diesel engine fast cold start electric glow plug design system, comprising:

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

[0015] The second processing module is used to obtain the performance parameters of the electric preheating plug based on the design parameters of the electric preheating plug;

[0016] The third processing module is used to perform multi-objective optimization of the performance parameters of the electric glow plug using a non-dominated sorting genetic algorithm, so as to obtain the optimal design scheme that satisfies the constraints of the total heating time of the electric glow plug when the cylinder reaches the ignition point and the space volume occupied by the electric glow plug.

[0017] Preferably, the first processing module includes:

[0018] The design parameters for 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 heat power per unit area.

[0019] Preferably, the second processing module includes:

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

[0021] The second processing unit evaluates the total heating time of the electric glow plug when the cylinder reaches the ignition point using a transient heat flux numerical simulation method. Based on the numerical simulation results, it constructs a mapping relationship between the total heating time of the electric glow plug when the cylinder reaches the ignition point and 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, using the optimal Latin hypercube sampling method and a generalized neural network. This enables rapid evaluation of the total heating time of the electric glow plug when the cylinder reaches the ignition point based on the electric glow plug design parameters.

[0022] As a preferred option, in the third module:

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

[0024] Compared with the prior art, the beneficial effects of the present invention are:

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

[0026] 2. This invention introduces the numerical calculation model of electric preheating plug intake heating, the optimal Latin hypercube sampling method, the generalized neural network surrogate model, and the non-dominated sorting genetic optimization algorithm into the optimization design of electric preheating plug, realizing multi-objective optimization of electric preheating plug, breaking the limitations of traditional optimization methods that mainly rely on manual trial and error, and greatly improving optimization efficiency and accuracy.

[0027] 3. This invention uses the total heating power of the electric preheating plug as an optimization constraint, ensuring the economy and reliability of the optimization scheme; it also incorporates the volume of the electric preheating plug into the optimization objective, effectively balancing the heating efficiency and structural compactness of the electric preheating plug. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0029] Figure 1 This is a flowchart illustrating the design method of a fast cold start electric glow plug for a diesel engine according to an embodiment of the present invention.

[0030] Figure 2 This is a geometric schematic diagram of the electric preheating plug model in the example. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Example 1:

[0034] like Figure 1 As shown, this embodiment of the invention provides a design method for a fast cold start electric glow plug for a diesel engine, comprising:

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

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

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

[0038] (4) The formula for calculating the volume V occupied by the electric preheating plug is as follows:

[0039] (5) The total heating time t of the electric glow plug when the cylinder reaches the ignition point is evaluated using the transient heat flow numerical simulation method. By simulating the transient heating process of the electric glow plug, the temperature of the oil-air mixture in the cylinder is monitored, and the total heating time of the electric glow plug when the cylinder reaches the ignition point is statistically analyzed. The computational domain of the transient heat flow numerical simulation method is the fluid domain composed of the geometric structures of the intake and exhaust ports, electric glow plug, intake and exhaust valves, nozzles, and cylinder. The inlet boundary condition is the velocity-temperature condition, the outlet boundary condition is the pressure boundary condition, the electric glow plug wall adopts the given unit area heat power condition, the computational domain is discretized using an 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) model. Taylor model, droplet collision and aggregation model adopts non-time counter model, droplet wall collision model adopts Wall-Film model and O'Rourke-Amsdenm model, combustion model adopts SAGE model, spatial discretization adopts second-order central difference scheme, and time discretization adopts first-order upwind scheme;

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

[0041] I) For the five design parameters in step (1): resistance wire coil diameter d, resistance wire coil pitch l, electric preheating plug length L, electric preheating plug diameter D, and electric preheating plug unit area heat power w, the range of values ​​for each design parameter is given. Within the range of design parameter values, the optimal Latin hypercube sampling method is used 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. Finally, (n+1)×(n+2) / 2 design schemes are formed.

[0042] II) For each design scheme in the sample set in process I), step (5) is used 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 glow plug when the cylinder reaches the ignition point and the design parameters (resistance wire coil diameter d, resistance wire coil pitch l, electric glow plug length L, electric glow plug diameter D, and electric glow plug unit area heat power w). The mapping expression is: t = f(d, l, L, D, w), where f is a function symbol, thereby quickly evaluating the total heating time t of the electric glow plug when the cylinder reaches the ignition point.

[0044] (7) The 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 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 through step (3), the space volume V occupied by the electric preheating plug is calculated through step (4), and the total heating time t of the electric preheating plug when the cylinder reaches the ignition point is quickly evaluated through process III in step (6). Finally, a design scheme that satisfies the constraint (the total heating power P of the electric preheating plug is less than a given value) is obtained, and 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 are both better.

[0045] Example 1:

[0046] (1) This embodiment is for an electric glow plug for a certain type of air-cooled diesel engine. The geometric model is shown in the attached figure. Figure 2 As shown, the selection of design parameters and performance parameters for this model refers to steps (1) and (2);

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

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

[0049] (4) To quickly assess the total heating time t of the glow plug when the cylinder reaches the ignition point, firstly, 50 samples are generated in the design space using the method described in step (6) process I, ensuring that the sample points are evenly distributed within the design space. Then, according to process II in step (6), the total heating time t of the glow plug when the cylinder reaches the ignition point for each sample is obtained. Finally, according to process III in step (6), a generalized neural network (GRNN) surrogate model is constructed to obtain the mapping relationship between the total heating time t of the glow plug when the cylinder reaches the ignition point and the design parameters. The accuracy of the surrogate model is verified using cross-validation. The predicted and calculated values ​​of the performance parameters are in good agreement, and the root mean square error (RMSE) is less than 0.1. It can be considered that the surrogate model in this example has high mapping accuracy and can be used for subsequent optimization.

[0050] (5) The non-dominated sorting genetic algorithm (NSGA-II) is used to perform multi-objective optimization on the electric preheating plug. The constraint 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. In the optimization process, the total heating power P of the electric preheating plug is calculated through step (3), and the space volume V occupied by the electric preheating plug is calculated through step (4). The total heating time t of the electric preheating plug when the cylinder reaches the ignition point is obtained through the constructed surrogate model. After optimization, the Pareto front solution set is obtained. The design scheme in the solution set is numerically simulated and verified. Finally, the optimal design scheme that satisfies the constraint is obtained, which has the optimal total heating time t of the electric preheating plug when the cylinder reaches the ignition point and the optimal space volume V occupied by the electric preheating plug.

[0051] (6) The optimal electric glow plug design was fabricated, and a low-temperature starting test of the diesel engine was conducted. The test was carried out in a low-temperature environment test chamber at three temperatures: -20℃, -43℃, and -50℃. The measured variable was the total heating time t of the electric glow plug when the cylinder reached the ignition point. As shown in Table 1, the test results showed that ignition was successful in all cases, and the total heating time of the electric glow plug when the cylinder reached the ignition point at each test temperature met the design specifications.

[0052] Table 1

[0053]

[0054] Example 2:

[0055] This invention also provides a diesel engine fast cold start electric glow plug design system, comprising:

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

[0057] The second processing module is used to obtain the performance parameters of the electric preheating plug based on the design parameters of the electric preheating plug;

[0058] The third processing module is used to perform multi-objective optimization of the performance parameters of the electric glow plug using a non-dominated sorting genetic algorithm, so as to obtain the optimal design scheme that satisfies the constraints of the total heating time of the electric glow plug when the cylinder reaches the ignition point and the space volume occupied by the electric glow plug.

[0059] As one embodiment of the present invention, the design parameters of the electric preheating plug include: resistance wire coil diameter, resistance wire coil pitch, electric preheating plug length, electric preheating plug diameter, and electric preheating plug unit area heat power.

[0060] As one embodiment of the present invention, the second processing module includes:

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

[0062] The second processing unit evaluates the total heating time of the electric glow plug when the cylinder reaches the ignition point using a transient heat flux numerical simulation method. Based on the numerical simulation results, it constructs a mapping relationship between the total heating time of the electric glow plug when the cylinder reaches the ignition point and 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, using the optimal Latin hypercube sampling method and a generalized neural network. This enables rapid evaluation of the total heating time of the electric glow plug when the cylinder reaches the ignition point based on the electric glow plug design parameters.

[0063] As one embodiment of the present invention, the constraint is: the total heating power of the electric glow plug is less than a given value, and the objective function is: to minimize the total heating time of the electric glow plug when the cylinder reaches the ignition point and to minimize the space volume occupied by the electric glow plug.

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

Claims

1. A design method for a fast cold start electric glow plug for a diesel engine, characterized in that, include: Select the design parameters for the electric preheating plug; Based on the design parameters of the electric preheating plug, the performance parameters of the electric preheating plug are obtained; A non-dominated sorting genetic algorithm was used to optimize the performance parameters of the electric glow plug for multiple objectives, and the design scheme with the optimal total heating time of the electric glow plug and the optimal space volume occupied by the electric glow plug when the in-cylinder reaches the ignition point satisfies the constraints. The design parameters for 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 heat power per unit area. The performance parameters of the electric glow plug include: the total heating power of the electric glow plug, the space volume occupied by the electric glow plug, and the total heating time of the electric glow plug when the cylinder reaches the ignition point. Among them, the total heating time of the electric glow plug when the cylinder reaches the ignition point is evaluated by the transient heat flow numerical simulation method. Based on the numerical simulation results, the optimal Latin hypercube sampling method and generalized neural network are used to construct the mapping relationship between the total heating time of the electric glow plug when the cylinder reaches the ignition point and 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. This enables the rapid evaluation of the total heating time of the electric glow plug when the cylinder reaches the ignition point based on the electric glow plug design parameters.

2. The design method for a diesel engine fast cold start electric glow plug as described in claim 1, characterized in that, The constraints are: the total heating power of the electric glow plug is less than a given value, and the objective function is: to minimize the total heating time of the electric glow plug when the cylinder reaches the ignition point and to minimize the space volume occupied by the electric glow plug.

3. A design system for a diesel engine's rapid cold start electric glow plug, characterized in that, include: The first processing module is used to select the design parameters for the electric preheating plug; The second processing module is used to obtain the performance parameters of the electric preheating plug based on the design parameters of the electric preheating plug; The third processing module is used to perform multi-objective optimization of the performance parameters of the electric glow plug using a non-dominated sorting genetic algorithm, so as to obtain the optimal design scheme that satisfies the constraints of the total heating time of the electric glow plug when the cylinder reaches the ignition point and the optimal space volume occupied by the electric glow plug. The first processing module is used to select the design parameters of the electric preheating plug. 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. The second processing module includes: The first processing unit is used to obtain the performance parameters of the electric glow plug, including: the total heating power of the electric glow plug, the space volume occupied by the electric glow plug, and the total heating time of the electric glow plug when the cylinder reaches the ignition point. The second processing unit evaluates the total heating time of the electric glow plug when the cylinder reaches the ignition point using a transient heat flux numerical simulation method. Based on the numerical simulation results, it constructs a mapping relationship between the total heating time of the electric glow plug when the cylinder reaches the ignition point and 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, using the optimal Latin hypercube sampling method and a generalized neural network. This enables rapid evaluation of the total heating time of the electric glow plug when the cylinder reaches the ignition point based on the electric glow plug design parameters.

4. The diesel engine fast cold start electric glow plug design system as described in claim 3, characterized in that, The third processing module is used to perform multi-objective optimization of the performance parameters of the electric glow plug using a non-dominated sorting genetic algorithm. The constraint is that the total heating power of the electric glow plug is less than a given value. The objective functions are: to minimize the total heating time of the electric glow plug when the cylinder reaches the ignition point and to minimize the space volume occupied by the electric glow plug.

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