JP4998765B2 - Engine performance prediction analysis system, prediction analysis method, and prediction analysis program - Google Patents

Description

  The present invention relates to an engine performance prediction analysis system and the like, and more particularly, to a prediction analysis system and the like that predict engine performance by analyzing an intake / exhaust flow of an engine using a CFD analysis program.

Conventionally, engine performance such as engine output and intake noise has been predicted by performing a simulation analysis of the flow of intake and exhaust of the engine using a CFD (Computational Fluid Dynamics) analysis program. Patent Document 1 discloses a fluid analysis system that analyzes a fluid flow based on three-dimensional CAD data.
Conventionally, by predicting engine performance by such CFD analysis, it is possible to reduce the number of development man-hours spent on repeating trial manufactures and experiments, thereby shortening the development and design period.

JP 2003-216660 A

  Here, the one-dimensional CFD analysis model is mainly represented by a pipe and a container, but such an analysis model is often created by a professional developer (expert) who is used to engine development and fluid analysis. . In other words, for example, when an expert wants to develop a new configuration of an intake / exhaust pipe of an engine, an analysis model can be constructed while taking into account the pressure pulsation characteristics of air to some extent. Can be obtained.

  Of course, it is important to obtain a realistic engine configuration, but in recent severe competition for engine development, it is also required to come up with a high-performance engine based on a completely new concept. However, the skilled person has a lot of development experience, so he is caught by the existing concept and often cannot make a new idea. For example, it is easy to think of adjusting the length of the pipe or changing the connection point of the resonator in order to give the intake system an inertial effect or resonance effect, but this has not been done so far For example, an unexpected idea of connecting an intake pipe and an exhaust pipe is avoided. On the other hand, developers who are unfamiliar with engine development may have an idea that is not confined to common sense, but in order to find out the configuration of intake and exhaust pipes that are realistic and based on a new idea, create a huge analysis model. In other words, it is difficult to shorten the development and design period.

  On the other hand, when trying to optimize the structure and dimensions of intake and exhaust pipes by CFD analysis, create and analyze a huge number of analysis models, even within the range of existing ideas, and compare the results. In some cases, it may not be possible to find an optimal solution due to time constraints in design and development.

  Therefore, the present invention has been made to solve the above-described problems of the prior art, and an object thereof is to provide a prediction analysis system and the like that can efficiently obtain a new and optimum intake / exhaust configuration. Yes.

In order to achieve the above object, the present invention is a predictive analysis system that predicts engine performance by analyzing the flow of intake and exhaust of an engine using a CFD analysis program, and performs a one-dimensional CFD analysis based on an operator's input. An analysis model generation means for generating a model, and a constraint condition for changing a model configuration and a constraint condition for changing a specification value of at least an intake pipe and / or an exhaust pipe of the CFD analysis model are set based on an input from an operator, respectively. The constraint condition setting means, the analysis model changing means for changing the CFD analysis model by changing the model configuration and specification values within the set constraint conditions, and the analysis by the CFD analysis program for the changed CFD analysis model The engine performance calculation means for calculating the engine performance and the CFD analysis model change and analysis model change means by the analysis model change means. A CFD in which optimum engine performance that satisfies a predetermined standard is calculated from repetitive execution means for repeatedly executing engine performance calculation by the engine performance calculation means for the changed CFD analysis model and a plurality of changed CFD analysis models. And an optimum model selecting means for selecting an analysis model.
In the present invention configured as described above, a CFD analysis model is generated by the analysis model generation means, and the model configuration and specification values of the analysis model are automatically changed by the repetition means and the engine performance is calculated. Furthermore, since the CFD analysis model in which the optimum engine performance satisfying the predetermined standard is selected by the optimum model selection means, the optimum intake / exhaust configuration with the specified specification values can be obtained efficiently. In particular, since the model configuration of the analysis model is changed by the analysis model changing means, a new model configuration that has not been conventionally available can be obtained very efficiently. As a result, a new and optimum intake / exhaust configuration can be obtained efficiently.

In order to achieve the above object, the present invention is a predictive analysis system that predicts engine performance by analyzing the flow of intake and exhaust of an engine using a CFD analysis program. An analysis model generation means for generating a CFD analysis model, a constraint condition for changing a model configuration and a constraint condition for changing a specification value of at least an intake pipe and / or an exhaust pipe of the CFD analysis model based on input from an operator, respectively Constraint condition setting means for setting, analysis model changing means for changing the CFD analysis model by changing the model configuration and specification values within the set constraint conditions, and analysis by the CFD analysis program for the changed CFD analysis model A first engine performance calculating means that executes and calculates the engine performance, and defines the relationship between the specification value and the engine performance. An empirical formula database storing formulas, a second engine performance calculating means for calculating engine performance using the empirical formulas stored in the experimental formula database for the modified CFD analysis model, and a first engine performance calculating means or A selection unit that selects one of the second engine performance calculation units according to a predetermined condition; a change of the analysis model by the analysis model change unit; a first engine performance calculation unit or a second engine performance calculation unit by the selection unit; And repeatedly executing means for repeatedly executing calculation of engine performance by the selected first engine performance calculating means or second engine performance calculating means for the changed CFD analysis model, and a plurality of changed CFDs A CFD analysis model in which the optimal engine performance that satisfies a predetermined standard is calculated from the analysis model. Is characterized by having the optimum model selection means for constant, the.
In the present invention configured as described above, a CFD analysis model is generated by the analysis model generation means, and the model configuration and specification values of the analysis model are automatically changed by the repetition means and the engine performance is calculated. Furthermore, since the CFD analysis model in which the optimum engine performance satisfying the predetermined standard is selected by the optimum model selection means, the optimum intake / exhaust configuration with the specified specification values can be obtained efficiently. In particular, since the model configuration of the analysis model is changed by the analysis model changing means, a new model configuration that has not been conventionally available can be obtained very efficiently. Furthermore, since it has a second engine performance calculation means for calculating the engine performance using an empirical formula that defines the relationship between the specification value and the engine performance, the engine performance is much shorter than the CFD calculation. Can be calculated, and the calculation time can be greatly shortened. As a result, a new and optimum intake / exhaust configuration can be obtained efficiently.

In the present invention, it is preferable that the selecting unit selects the first engine performance calculating unit when the analysis model changing unit changes the model configuration and calculates the engine performance for the changed model configuration for the first time. When the analysis model changing means changes the specification value and calculates the engine performance for the second and subsequent times for the same model configuration, the second engine performance calculating means is selected.
In the present invention configured as described above, when calculating the engine performance for the first time, the engine performance is calculated by the first engine performance calculation means by the CFD analysis program, and the accuracy of the result of the engine performance is maintained. From the second time onward, the engine performance is calculated by the second engine performance calculation means based on the empirical formula, so that the calculation time can be shortened more reliably.

In the present invention, preferably, when an empirical expression capable of calculating the engine performance is not stored in the empirical expression database for the CFD analysis model changed by the analysis model changing means, the specification value of the CFD analysis model Is changed a plurality of times with a predetermined change width by the analysis model changing means, the engine performance is calculated by the first engine performance calculating means for each of the plurality of CFD analysis models obtained by the change, and these calculated engine performances are calculated. And empirical formula generation means for generating an empirical formula by performing multiple regression analysis based on the specifications of the plurality of CFD analysis models.
In the present invention configured as described above, even if the experimental formula is not stored in the experimental formula database, the experimental formula is automatically generated by the experimental formula generating means. It is possible to reduce the calculation time more reliably by performing the engine performance using the equation.

In the present invention, preferably, a CFD analysis model generated in the past and a past case database storing analysis results regarding engine performance in the CFD analysis model, and a CFD analysis model changed by the analysis model changing means are also provided. If the empirical formula that can calculate the engine performance is not stored in the empirical formula database, multiple regression analysis based on the specifications of the CFD analysis model stored in the past case database and the analysis results on the engine performance in the CFD analysis model And an empirical formula generating means for generating an empirical formula.
In the present invention configured as described above, even if the experimental formula is not stored in the experimental formula database, the experimental formula is automatically generated by the experimental formula generating means. It is possible to reduce the calculation time more reliably by performing the engine performance using the equation.

In the present invention, it is preferable that the constraint condition setting unit sets at least a range of the length of the intake pipe and / or the exhaust pipe as a constraint condition of the specification value.
In the present invention configured as described above, it is possible to efficiently change the analysis model while suppressing the analysis model to be calculated from becoming infinite.

In the present invention, it is preferable that the constraint condition setting means sets at least the connection position and the number of the intake pipe and / or exhaust pipe as the constraint condition of the model configuration in the model configuration related to the intake pipe and / or the exhaust pipe. .
In the present invention configured as described above, it is possible to efficiently change the analysis model while suppressing the analysis model to be calculated from becoming infinite.

  In order to achieve the above object, the present invention is a computer-aided prediction analysis method for predicting engine performance by analyzing an engine intake / exhaust flow using a CFD analysis program, based on operator input. An analysis model generation process for generating a one-dimensional CFD analysis model, a constraint condition for changing the model configuration of at least an intake pipe and / or an exhaust pipe of the CFD analysis model, and a constraint condition for changing a specification value are input by an operator. CFD analysis program for the CFD analysis model after the change, the constraint condition setting step that is set based on the model, the analysis model changing step that changes the CFD analysis model by changing the model configuration and specification values within the set constraint conditions An engine performance calculation process for calculating engine performance by executing an analysis according to The engine performance is repeatedly calculated by the engine performance calculation process for the CFD analysis model and the CFD analysis model after the change, and the optimum engine performance that satisfies a predetermined standard is determined from a plurality of CFD analysis models after the change. And an optimum model selection step for selecting the CFD analysis model for which the above is calculated.

  In order to achieve the above object, the present invention is a computer-aided prediction analysis method for predicting engine performance by analyzing an engine intake / exhaust flow using a CFD analysis program, based on operator input. An analysis model generation process for generating a one-dimensional CFD analysis model, a constraint condition for changing the model configuration of at least an intake pipe and / or an exhaust pipe of the CFD analysis model, and a constraint condition for changing a specification value are input by an operator. CFD analysis program for the CFD analysis model after the change, the constraint condition setting step that is set based on the model, the analysis model changing step that changes the CFD analysis model by changing the model configuration and specification values within the set constraint conditions Engine performance calculation step for calculating engine performance by executing analysis according to the above, and a modified CFD analysis model A second engine performance calculation step for calculating engine performance using an experimental formula stored in an experimental formula database storing an experimental formula that defines the relationship between the specification value and the engine performance, and the first engine performance A selection step for selecting either the calculation step or the second engine performance calculation step according to a predetermined condition, and changing the analysis model by the analysis model change step, the first engine performance calculation step by the selection step, or the second step The engine performance calculation process is selected, and the engine performance calculation is repeatedly executed by the selected first engine performance calculation process or the second engine performance calculation process for the changed CFD analysis model, and a plurality of changes are made. Optimum to select a CFD analysis model for which the optimal engine performance that satisfies the predetermined criteria is calculated from the later CFD analysis model Predictive analysis method of engine performance, characterized in that it comprises a Dell selecting step.

  In order to achieve the above object, an engine performance prediction analysis program according to the present invention is a prediction analysis program for an analysis computer that analyzes engine intake / exhaust flow using a CFD analysis program to predict engine performance. Then, a one-dimensional CFD analysis model is generated based on the input of the worker, and a constraint condition for changing the model configuration and a constraint condition for changing the specification value of at least the intake pipe and / or the exhaust pipe of the CFD analysis model are set. Each is set based on the input of the worker, the model configuration and specification values are changed within the set constraints, the CFD analysis model is changed, and the CFD analysis model after the change is executed by the CFD analysis program. The engine performance is calculated and the CFD analysis model is changed and the CFD analysis model after the change is used. There by repeatedly executing the calculation of the engine performance, the CFD analysis model after several changes, controls the analyzing computer so as to select a CFD analysis model optimum engine performance that meets the predetermined criterion is calculated.

In order to achieve the above object, an engine performance prediction analysis program according to the present invention is a prediction analysis program for an analysis computer that analyzes engine intake / exhaust flow using a CFD analysis program to predict engine performance. Then, a one-dimensional CFD analysis model is generated based on the input of the worker, and a constraint condition for changing the model configuration and a constraint condition for changing the specification value of at least the intake pipe and / or the exhaust pipe of the CFD analysis model are set. Each is set based on the input of the operator, and the CFD analysis model is changed by changing the model configuration and specification values within the set constraints, and the analysis by the CFD analysis program is executed for the changed CFD analysis model . the empirical formula for defining the relationship between the calculated or specification values and engine performance of the engine performance due to Any calculation of engine performance using paid was stored in the empirical formula database empirical formula is selected by a predetermined condition, to calculate the engine performance based on the selection, modify the CFD analysis model, the modified CFD analysis model The calculation of engine performance based on the CFD analysis program or the selection of calculation of engine performance using an empirical formula and the calculation of engine performance based on the selection of the changed CFD analysis model are repeatedly executed, and after a plurality of changes The computer for analysis is controlled so as to select a CFD analysis model for which the optimum engine performance satisfying a predetermined criterion is selected from the CFD analysis models.

  According to the prediction analysis system and the like according to the present invention, a new and optimum intake / exhaust configuration can be obtained efficiently.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
First, the main configuration of the engine performance analysis system according to the first embodiment of the present invention will be described. FIG. 1 is a schematic configuration diagram of an engine performance analysis system according to a first embodiment of the present invention.
The analysis system according to the present embodiment automatically changes the configuration and specification values of the intake and exhaust pipes with respect to the base one-dimensional CFD analysis model and calculates the engine performance after such change by CFD calculation. By repeating such changes and calculations, an optimum engine configuration, particularly, an intake / exhaust pipe configuration is obtained. Examples of engine performance include output (torque), intake sound, exhaust sound, fuel consumption, emission, and the like.

  As shown in FIG. 1, the analysis system 1 includes a CFD analysis system 2 and a CAD system 4. The computer 6 of the CFD analysis system 2 stores an engine performance prediction program 8 that controls the processing of the analysis system 1 in its storage device (not shown) or memory (not shown). 8 includes a model generation program 10, a pre-post program 12, a model configuration change program 14, an optimization program 16, and a CFD analysis program 18. The computer 6 also has a CPU, an input / output device, a monitor, and the like (not shown).

The model generation program 10 uses the data stored in the model database 20 to cause an operator to construct an engine model having a model configuration as shown in FIG. A program for setting and generating a one-dimensional CFD analysis model. Specifications include specifications that define the shape such as dimensions and angles, specifications related to characteristics that affect the flow of intake and exhaust, such as resistance loss and thermal conductivity, and pressure and temperature at the end of the pipe. There are specifications regarding the boundary conditions.
The model database 20 stores a plurality of component models (element models defined for each specific shape and characteristic) used to create a one-dimensional analysis model. The part model includes “pipe”, “container”, “closed end”, “open end”, “branch pipe”, “cylinder”, “resonator”, and the like.

  FIG. 2 shows a model configuration constructed by combining component models. In the example of FIG. 2, the component models are arranged and connected to the resonator (i16, v2), the air cleaner (v1), the surge tank (i9 to i11), the intake passage (i5 to i8, i12, i13), the intake air A port (i1 to i4), an exhaust port (e17 to e20), an exhaust manifold (e21 to e27), and a catalyst (e28) are represented. Here, in the engine model shown in FIG. 2, i1 to i16 and e17 to e28 are “tube” models, v1 and v2 are “container” models, and c1 to c4 are “cylinder” models. It is a model. In addition, it is possible to form a throttle valve, an EGR passage, etc., and to express the surge tank with a container model. The model database 20 also stores analysis models generated in the past.

Next, the pre-post program 12 is a program that mainly performs a series of processes such as input of constraint conditions and optimization conditions for changing an analysis model, output of results, and the like by an operator.
Next, the model configuration change program 14 is a program for changing the model configuration within predetermined constraints based on the analysis model generated by the model generation program 10. In the present embodiment, the model configuration is changed by adding or separating the part model to the base analysis model. The addition or separation of the part model is performed on the connection part between the part models of the analysis model as a base.

Next, the optimization program 16 changes the model configuration by the model configuration change program 14, changes each specification value as a function of the optimization program 16, and analyzes the changed analysis model by the CFD analysis program 18. Is a program that selects an analysis model that shows high-performance engine performance from a plurality of analysis models obtained by the change. In addition, the optimization program 16 selects an analysis model that satisfies the optimization criterion set based on the operator's input.
Next, the CFD analysis program 18 is a program for analyzing the flow of the intake and exhaust of the engine by CFD calculation of a one-dimensional analysis model, and calculates the engine performance in consideration of the flow of intake and exhaust and the combustibility in the combustion chamber. It is a possible program. As an analysis result, engine torque, intake sound, fuel consumption, etc. are output.

  Next, a CAD program 24 is stored in the computer 22 of the CAD system 4. The CAD program 24 is a general-purpose CAD program for machine design and structural analysis. The design database 26 stores three-dimensional CAD data of various engines. The CAD program 24 has a function of reading three-dimensional CAD data from the design database 26 or storing CAD data in the design database 26.

  Note that the computer 6 of the CFD analysis system 2 is preferably a computer (not shown) in which a plurality of high-speed server computers that can cope with a large amount of computation of the three-dimensional CFD are connected in parallel. In addition, a plurality of client terminals (not shown) may be connected via a network so that an operator can perform an analysis operation on such terminals.

Next, processing contents in the analysis system according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a flowchart showing a flow of processing contents in the analysis system according to the first embodiment of the present invention, and FIG. 4 is a one-dimensional analysis for explaining designation of a connection part that can add or disconnect a part model. FIG. 5 is a schematic diagram illustrating an example of a model. FIG. 5 is a diagram illustrating an evaluation condition pattern of torque characteristics as an example of an optimization determination criterion. FIGS. 6 to 10 each have a changed model configuration. It is a schematic diagram which shows the example of a one-dimensional analysis model. Note that “S” in FIG. 3 indicates each step.
Each step described below is an example in which an output torque is predicted as engine performance by the engine performance prediction program 8 and each program 10, 12, 14, 16, 18 included in the program 8, and exceeds a predetermined standard. An intake / exhaust configuration in which an optimum output torque can be obtained, and a torque curve thereof are finally output.

First, as shown in FIG. 3, one S-dimensional CFD analysis model (base model) is generated in S1.
Specifically, the operator appropriately selects the above-described component model stored in the model database 20 on a predetermined screen displayed by the model generation program 10, and further arranges and connects the one-dimensional model. Build an analysis model. In S1, such a work is accepted, and a one-dimensional analysis model having a model configuration as shown in FIG. 2 is generated, for example. In S1, it is preferable to create a model having a basic configuration as shown in FIG. 2 or a model representing an existing engine configuration when an existing engine is improved.

In S <b> 1, the values of the above-described specifications (specifications that define the shape, specifications related to characteristics, specifications related to boundary conditions) and the number of meshes input by the operator are accepted. It should be noted that specification values that define the shape of the engine may be automatically read from CAD data in the design database 26.
In this S1, a one-dimensional CFD analysis model (one-dimensional base model) that can execute an analysis based on data of these specification values and the number of meshes and data of a model configuration that represents the arrangement and connection of a plurality of component models. ) Is generated. Further, the generated analysis model is stored in the model database 20. Note that in S1, an analysis model may be generated by reading an analysis model generated in the past stored in the model database 20 or by correcting the read model.

  Next, in S2, the analysis model generated in S1 is analyzed by the CFD analysis program 18, and the presence or absence of a calculation error is checked (trial calculation). Next, when it is determined in S3 that there is a calculation error, the process returns to S1 to prompt the operator to input a model construction or specification value again. If it is determined that there is no calculation error, the process proceeds to S4.

Next, in S4, as shown in FIG. 4, the model configuration of the analysis model generated in S1 is displayed on the screen, and the operator is allowed to specify a connection part to which a part model can be added or detached. In the example of FIG. 4, a connection part n1 between the pipe i1 and the pipe i5, a connection part n2 between the pipe i2 and the pipe i6, and a connection part n3 between the pipe i5 and the pipe i9 are designated.
In the present embodiment, the addition of a component model is to add a new component model by connecting it to a designated connection unit with respect to the base model generated in S1. For example, for a tube model, connect both ends to their designated connections, and connect only one end to the designated connection and the other end to the atmosphere. Opening is also included. On the other hand, the part model separation means that a part model whose both ends or one end is connected to a designated connecting portion is separated, that is, is deleted from among the part models already incorporated in the base model generated in S1. That is. In this embodiment, a pipe model is added or separated as a part model.

In S4, the pipe models connected to (added to) these connection portions n1 to n3 (see the pipe models i29 and i30 in FIGS. 6 to 10) and the base model are incorporated in advance, and both ends are connected. Regarding the pipe model already connected to the connection parts n1 to n3 (refer to the pipe model of i5), in the present embodiment, the length and diameter of the pipe model among a plurality of specifications that define such a pipe model. Is set as a changeable parameter for optimization. Note that the changeable specifications may be set based on the input of the operator.
Further, in S4, input by an operator who can change the specification other than the specification related to the part model, such as the valve timing and the compression ratio, is accepted, and such input specification is also optimized. Set as a changeable specification parameter.

Next, in S5, an input by the operator of the constraint condition regarding the change of the model configuration is accepted. In the present embodiment, the number of pipes that can be allowed in the same path, that is, the number of pipe models that can be connected between the connection portions n1 to n3, is set as a constraint based on the input of the operator. For example, when the number of tube models as a restriction condition is input as three, as shown in FIG. 10, the number of additional tube models is set to two between the connection portion n1 and the connection portion n3. The maximum number is 3.
Next, in S6, the input by the operator of the constraint condition regarding the change of the specification value is accepted. In the present embodiment, the upper and lower limit values of the length and diameter of the pipe model and the upper and lower limit values of the specification values such as the valve timing and compression ratio set in S4 are set as constraints based on the operator's input. Set. In the present embodiment, in the following step (S10), only the specification values for which this constraint condition is set are changed.

Next, in S7, an input of optimization conditions related to engine performance and the like by the worker is received. In the present embodiment, an engine speed range that maximizes the output torque is set as an optimization condition by an operator input. For example, it is set to 4000 to 5000 rpm. Note that the engine load may be set as an operation condition for optimizing the engine performance.
Next, in S8, an optimization criterion is set based on the operator's input. Optimization criteria will be described with reference to FIG.

The base value shown in FIG. 5 is a target value of torque in optimization. This base value is set in advance so that a torque value superior to the conventional one can be obtained if the intake / exhaust configuration can basically obtain a torque exceeding the base value.
Here, for example, a sports car and a family car may have different torque output (torque characteristics) with respect to the engine speed. Therefore, in S8, several torque characteristics are prepared in advance as evaluation conditions for the base value.
As shown in FIG. 5, the evaluation condition 1 is a torque characteristic that exceeds the base value in the entire engine speed, has a large area, and has a large variation. The evaluation condition 2 is a base value at a part of the engine speed. The evaluation condition 3 is a torque characteristic that exceeds the base value in the entire engine speed range, is narrow, and has little variation. In S8, the worker is made to select any one of the evaluation conditions 1 to 3.

  Next, in S9, one analysis model for simulation used for optimization calculation is generated. In S9, an additional pipe model is connected to the connection parts n1 to n3 designated in S4 by the model configuration change program 14 with respect to the analysis model generated in S1, or the pipe model already generated is disconnected. Such a change is executed within the constraints of the model configuration input in S5. In S9, for example, as shown in FIG. 6, an analysis model in which the pipe model i29 is connected to the connection part n1 and the connection part n3 is generated.

  Next, in S10, any one of the changeable parameters (length and diameter of the pipe model, valve timing, etc.) is changed with respect to the analysis model generated in S9. In S10, this change is performed with a predetermined change width every time the process of S10 is performed. For example, if the length of the tube model, it is predetermined as 2 mm intervals. Such a change width is a relatively small numerical interval required for optimization. The change with such a change width is executed within the constraint condition of the specification value set in S6.

Further, in S10, after the pipe model is added in S9, when the process of S10 is performed for the first time with the model configuration, the specification values of the added pipe model are converted into the pipe model (i5 Etc.) to the same value. Or you may make an operator perform input. The length and diameter of the added pipe model are also set as changeable parameters for optimization.
Next, in S11, an analysis by the CFD analysis program 18 is performed on the analysis model whose specification values are changed in S10, and a torque curve is calculated as an analysis result.

  Next, in S12, an evaluation score is calculated for the torque curve calculated in S11. From the viewpoint of the evaluation point, whether the torque value is maximum at the engine speed set in S7, how much the torque value matches the evaluation curve selected in S8, or the area of the torque curve, etc. calculate. Then, the evaluation point and the calculated torque curve data are recorded in a storage device or the like.

  Next, in S13, it is determined whether or not the processes in S10 to S12 are repeated. In S13, the determination is made from the viewpoint of the usefulness of continuation of the processing obtained from the number of executions of the processing in S10 to S12 or the recording result in S12. Moreover, you may consider both of them. From the viewpoint of usefulness, for example, when the torque value has almost converged and no significant increase can be expected even if the calculation continues, or when the elongation is very small compared to the calculation cost (time, etc.) It is determined that the repetition of is stopped.

If it is determined in S13 that the repetitive process is continued, the process returns to S10, and after changing the specification value, the processes of S11 and S12 are executed.
If it is determined in S13 that the repetitive process is not continued, the repetitive process is stopped and the process proceeds to S14 in order to shorten the calculation time of the entire flow shown in FIG. Of course, when the specification values are changed (S10) within the constraint condition (S6) for all the specifications set in S4, the process proceeds to S14.
In S14, the model configuration is further changed (S9) from the viewpoint of the usefulness of continuation of the processing obtained from the number of executions of the processing of S9 to S13, and the recording result of S12, in substantially the same manner as S13, It is determined whether to repeat the processes of S10 to S13.

If it is determined in S14 that the repetitive process is continued, the process returns to S9, the model configuration is further changed, and then the processes of S10 to S13 are repeated.
Here, an example of changing the model configuration will be described. For example, FIGS. 6 to 8 are examples in which one pipe model is added, and FIGS. 9 and 10 are examples in which two pipe models are added. Further, in the model as shown in FIG. 8, a model configuration in which the i5 pipe is separated is also generated.
As described above, according to the present embodiment, for example, as shown in FIG. 7, the flow of intake air from the surge tank to the second intake port (i2) is set to two systems, or as shown in FIGS. In this way, the first intake port (i1) and the second intake port (i2) are communicated with each other, or as shown in FIGS. An analysis model having a new intake / exhaust configuration that has not been conventionally used, such as using three or three, is automatically generated. Furthermore, in addition to such an example, it is possible to obtain an unusual intake / exhaust configuration that is not conventional, such as connecting an intake pipe and an exhaust pipe, or connecting a pipe that directly introduces outside air to the intake port.

If it is determined in S14 that the repetitive process is not continued, the repetitive process is stopped and the process proceeds to S15 in order to shorten the calculation time of the entire flow shown in FIG. Of course, if all changes (S9) have been made within the constraint (S5), the process proceeds to S15.
Next, in S15, the plurality of analysis results recorded in S12 are compared. In the present embodiment, a plurality of torque curves that are analysis results are compared, and a torque curve that matches the evaluation condition selected in S8 and that exhibits the highest torque is determined. Then, an analysis model (model configuration and specifications after change) from which the torque curve is obtained is selected. An analysis model with the highest evaluation score calculated in S12 may be selected.
Next, in S16, the analysis model selected in S15 and its torque curve are displayed on the screen and stored in a storage device or the like. Further, all calculation results may be stored and displayed.

As described above, according to this embodiment, a certain analysis model is generated (S1), and the model configuration and specification values of the analysis model are automatically changed and the optimization calculation is performed. An exhaust configuration can be obtained efficiently. In particular, since the model configuration is automatically changed, a new intake / exhaust configuration unprecedented can be reliably obtained in a short development period, regardless of the experience of the operator.
In addition, since the model configuration and the specification values are changed within predetermined constraints, it is possible to prevent the calculation time from being excessively increased. In particular, as a restriction condition for the pipe model, only the length and diameter of the pipe that greatly affects the flow of intake and exhaust can be changed, and the number of pipes is also restricted, so the analysis model to be calculated is infinite. The analysis model can be efficiently changed so as to suppress the increase and obtain a more optimal result with a smaller number of calculations.

Next, an engine performance analysis system according to a second embodiment of the present invention will be described mainly with reference to FIGS. FIG. 11 is a schematic configuration diagram of an engine performance analysis system according to the second embodiment of the present invention, and FIG. 12 is a diagram illustrating an example of a preparatory difference between empirical formulas.
The analysis system according to the second embodiment basically automatically changes the configuration and specification values of the intake and exhaust pipes with respect to the base one-dimensional CFD analysis model, as in the first embodiment described above. At the same time, the engine performance after such a change is calculated, and the change and the calculation are repeated to obtain an optimal engine configuration, particularly an intake / exhaust pipe configuration. The second embodiment is different from the first embodiment in that the engine performance of the analysis model after the change is calculated by either the CFD calculation by the CFD analysis program or the calculation using the empirical formula. Different. Hereinafter, this different point will be mainly described, and detailed description of the same points as in the first embodiment will be omitted.

  First, as shown in FIG. 11, the analysis system 30 according to the second embodiment includes a CFD analysis system 32 and a CAD system 4. The computer 6 of the CFD analysis system 32 stores an engine performance prediction program 34 in its storage device (not shown) or memory (not shown). The engine performance prediction program 34 includes the model generation program 10, the pre-post A program 12, a model configuration change program 14, an optimization program 36, and a CFD analysis program 18 are included. In the description of the second embodiment, for the sake of convenience, the same reference numerals as those in the first embodiment are assigned to programs and databases similar to those in the first embodiment.

  The model generation program 10, the pre-post program 12, the model configuration change program 14, and the CFD analysis program 18 each generate a one-dimensional CFD analysis model from the component models stored in the model database 20, as in the first embodiment. Program, a program that performs a series of processing such as input of constraint conditions and output of results, a program that changes the model configuration of an analysis model by adding or removing a part model, and CFD calculation of a one-dimensional analysis model It is a program.

  The optimization program 36 in the present embodiment calculates the model performance by the model configuration change program 14, changes the specification values as functions of the optimization program 36, and calculates the engine performance for the analysis model after the change. It is a program that repeatedly executes and selects an analysis model showing high performance engine performance from a plurality of analysis models obtained by modification. In the optimization program 36, the engine performance is calculated based on a predetermined condition by either calculation by CFD calculation by the CFD analysis program 18 or calculation by an empirical formula stored in the empirical formula database 38. Further, the optimization program 36 selects an analysis model capable of obtaining engine performance that satisfies a predetermined optimization criterion, as in the first embodiment.

The experimental formula database 38 stores experimental formulas that define the relationship between engine specifications and operating conditions and engine performance. The specifications of the engine are, for example, the length and diameter of the intake and exhaust pipes, the compression ratio, the valve lift amount, etc., the operating conditions are the engine speed and the engine load, and the engine performance is the torque, intake sound, intake air amount (Volumetric efficiency). The empirical formula is obtained by performing multiple regression analysis on the results obtained by testing the actual engine or CFD analysis in advance for each engine performance. The database 38 stores such empirical formulas for each engine performance. For example, with respect to the intake air amount (volumetric efficiency), the following empirical formulas, which are defined by the coefficients a1 to a9 and the various specifications, and can directly calculate the performance values are stored.
ηv = a1 × intake pipe length / intake pipe diameter + a2 × compression ratio +... + a9 × valve lift amount For example, a torque value is calculated from ηv obtained by this empirical formula.
Moreover, the following empirical formulas that can be used to relatively calculate engine performance, which are defined by coefficients and specifications, are stored.
Torque change amount = a1 × compression ratio change amount With such an empirical formula, it is possible to obtain the torque change amount according to the change amount when a certain specification value is changed.

  Such an empirical formula has been confirmed in advance in accuracy of calculation, and an example thereof is shown in FIG. FIG. 12 shows a predicted value obtained by substituting the specification value of an analysis model for an engine analysis model into an empirical formula, and an actual measurement value obtained by analyzing the analysis model. The obtained results are plotted as indicated by black circles in the figure. In FIG. 12, a plurality of results for a plurality of engines having different specification values are plotted. In FIG. 12, among the three solid lines extending obliquely, the line extending in the middle is a line with an error of 0% where the predicted value and the measured value match, and the lines on both sides thereof are lines with an error of ± 3%. . As described above, in this embodiment, the engine performance is calculated with an accuracy of about ± 3% of error by an empirical formula.

Next, the CAD system has a CAD program 24 and a design database 26 as in the first embodiment.
Also in the second embodiment, as in the first embodiment, the computer 34 of the CFD analysis system 32 connects a plurality of high-speed server computers in parallel, and further connects a plurality of client terminals (not shown). You may connect with a network.

Next, processing contents in the analysis system according to the second embodiment of the present invention will be described with reference to FIG. FIG. 13 is a flowchart showing the flow of processing contents in the analysis system according to the second embodiment of the present invention. Note that “S” in FIG. 13 indicates each step.
Each step described below is an example of predicting output torque as engine performance by the engine performance prediction program 34 and the programs 10, 12, 14, 18, 36 included in the program 34, as in the first embodiment. It is. Note that the following processes of S21 to S29, S31, S32, and S35 to S39 are the same as those of the first embodiment, and detailed description thereof will be omitted below.

  As shown in FIG. 13, S21 to S29 perform the same processing as S1 to S9 of the first embodiment shown in FIG. That is, a one-dimensional CFD analysis model (base model) is generated in S21, trial calculation of the analysis model is performed in S22, and whether or not there is a calculation error is determined in S23. Further, in S24, the operator can specify a connection part that can add or detach a part model and input a changeable specification, and the changeable specification can be changed for optimization. Set as a specification parameter. Further, in S25 and S26, a constraint condition regarding the change of the model configuration and a constraint condition regarding the change of the specification value are set based on the input of the operator, respectively, and in S27 and S28, the optimization condition and optimization regarding the engine performance are set. Is set based on the operator's input. In S29, a simulation model used for calculation for optimization is generated by adding or disconnecting a part model to the connection portion specified in S24.

Next, the process proceeds to S30, and it is automatically selected whether the engine performance of the analysis model generated in S29 is calculated by CFD calculation or empirical formula as a prediction method.
In this embodiment, in S30, when the model configuration is changed in S29 and the process proceeds to S30 for the first time, that is, when the engine performance is first calculated in the model configuration changed in S29, calculation by CFD calculation is selected. When calculating the engine performance for the second and subsequent times in the model configuration changed in S29, calculation based on an empirical formula is selected. If the experimental formula that can calculate the engine performance of the analysis model generated in S29 is not stored in the experimental formula database 38, the calculation by the CFD calculation is selected.

If calculation by CFD calculation is selected in S30, the process proceeds to S31, and as with the first embodiment, changeable parameters (length and diameter of the pipe model) are added to the analysis model generated in S29. , Valve timing, etc.) is changed within the constraint conditions of the specification values set in S26. In S31, as described above, this change is changed at a change width of, for example, an interval of 2 mm as long as the length of the tube model every time the process of S31 is performed.
When a pipe model is added in S29 and the process of S31 is first performed with the model configuration, the specification value of the added pipe model is the same value as the pipe model (i5 etc.) generated in advance. Set to. The length and diameter of the added pipe model are also set as changeable parameters for optimization.
Next, in S32, similarly to the first embodiment, the analysis by the CFD analysis program 18 is executed on the analysis model whose specification values are changed in S31, and a torque curve is calculated as an analysis result.

On the other hand, if calculation by an empirical formula is selected in S30, the process proceeds to S33, and engine performance (torque in the present embodiment) for analysis is calculated from the experimental formula stored in the experimental formula database 38. An appropriate empirical formula that can be used and that can calculate the engine performance of the analysis model having the model configuration changed in S29 is automatically selected.
In S33, the specification value and the operating condition to be substituted into the empirical formula are determined. The specification value to be substituted is the specification value of the analysis model generated in S29. In this case, any one of the changeable specification parameters (length and diameter of the pipe model, valve timing, etc.) is set. change. Further, if there is a pipe model added in S29, when the process of S33 is performed for the first time with the model configuration, the specification values of the added pipe model are changed to those of the pipe model (i5 etc.) generated in advance. The original price. The length and diameter of the added pipe model are also set as changeable parameters for optimization. The operating condition to be substituted here is the engine speed.

Next, the process proceeds to S34, and the torque curve is calculated by substituting the specification values and the operating condition values into the empirical formula selected in S33. For example, the torque curve is calculated based on a plurality of results obtained by individually substituting the engine speed set in increments of 100 rpm into the empirical formula.
Here, as described above, in the model configuration changed in S29, the first engine performance is calculated by CFD calculation, and the second and subsequent times are calculated by empirical formulas. In such a case, a change amount (for example, torque change amount) of the engine performance corresponding to the change amount of the specification value after the second time is obtained using the above-described empirical formula capable of relatively calculating the engine performance. The engine performance is calculated by adding / subtracting the change amount to the engine performance (for example, torque) obtained by the simulation. Therefore, even if the calculation time is shortened by using the empirical formula, the accuracy of the calculated engine performance value can be ensured at a practical level.

  Next, after the processing of S32 or S34 is completed, the process proceeds to S35, and in the same manner as in the first embodiment, the torque value calculated in S32 or S34 has the maximum torque value at the engine speed set in S27. The evaluation score is calculated from the viewpoint of how much the evaluation condition selected in S8 is met. Then, the evaluation point and the calculated torque curve data are recorded in a storage device or the like.

Next, in S36, as in the first embodiment, it is determined whether or not the processes in S30 to S35 are repeated. If it is determined that the repeated process is to be continued, the process returns to S30, and after selecting the prediction method, the specifications are further changed in S31 or S33, and the process of S32 or S34 and the process of S35 are executed.
If it is determined in S36 that the repetitive process is not continued, the process proceeds to S37, and it is determined whether or not the processes of S29 to S36 are repeated as in the first embodiment. If it is determined that the repetitive process is to be continued, the process returns to S29, the model configuration is further changed, and then the processes of S30 to S36 are repeated.

Next, in S38, as in the first embodiment, an analysis model that matches the evaluation condition selected in S28 and has a torque curve showing the highest torque is selected.
Next, in S39, as in the first embodiment, the analysis model selected in S38 and its torque curve are output.

  According to the second embodiment, an optimum new intake / exhaust configuration can be obtained efficiently as in the first embodiment described above. Further, in the second embodiment, since the engine performance is calculated not only by the CFD calculation but also by an empirical formula, the calculation time can be greatly shortened. In particular, the calculation of the first engine performance after changing the model configuration is performed by CFD calculation and the second and subsequent calculations are performed by empirical formulas, so the calculation time can be shortened more reliably. Furthermore, since the calculation of the engine performance by the empirical formula uses the result of the CFD calculation, the calculation accuracy of the engine performance can be maintained even if the empirical formula is used.

Next, a first modification of the second embodiment will be described with reference to FIGS. 14 and 15. FIG. 14 is a schematic configuration diagram of an engine performance analysis system according to a first modification of the second embodiment of the present invention, and FIG. 15 shows a process of the analysis system according to the first modification of the second embodiment of the present invention. It is a flowchart which shows a part of flow of content.
This modification is an example in which a processing step for generating an empirical formula by CFD calculation and the result of multiple regression analysis is added to the processing flow (FIG. 13) in the second embodiment described above, and the analysis generated in S29. These processing steps are performed when the experimental formula that can calculate the engine performance of the model is not stored in the experimental formula database 38.

First, as shown in FIG. 14, the engine performance prediction program 44 of the prediction analysis system 40 according to this modification is obtained by adding an empirical formula generation program 46 to the engine performance prediction program 34 according to the second embodiment shown in FIG. It is. The other programs 10 and the like, the database 20 and the like, and the CAD system 4 are the same as those in the second embodiment, and description thereof will be omitted below.
The empirical expression generation program 46 in the first modification is a program that performs CFD analysis on the analysis model generated in S29 of FIG. 13 at a predetermined number of times and conditions, and generates an empirical expression by performing multiple regression analysis on the analysis result. is there. This will be further described with reference to FIG.

As shown in FIG. 15, in this modified example, after the process of S29 (FIG. 13) is completed, the process proceeds to S40, and an experimental expression capable of calculating the engine performance of the analysis model generated in S29 is stored in the experimental expression database 38. It is determined whether or not. If stored, the process proceeds to S30 (FIG. 13), and the processes of S30 to S39 are performed as described above in the second embodiment.
If it is determined in S40 that the empirical formula is not stored, the process proceeds to S41.
In S41, the analysis by the CFD analysis program 18 is repeated for a plurality of analysis models in which the changeable parameters (length and diameter of the pipe model, valve timing, etc.) are changed with respect to the analysis model generated in S29. Execute. In S41, a value larger than the change width changed in S31 described above, for example, if the length of the tube model is changed with a change width of, for example, an interval of 20 mm, is thinned out to a value that allows multiple regression analysis. . In this way, an analysis result for generating an empirical formula is acquired in a short analysis time.

  Next, in S42, the multiple regression analysis is performed on the specification value of the analysis model analyzed in S41, the analysis conditions such as the engine speed, and the analysis result obtained in S41. In S43, the multiple regression analysis is performed. From the result, an empirical formula is generated. Further, the generated experimental formula is stored in the experimental formula database 38. After the process by S43 is completed, the process proceeds to S30 (FIG. 13), and the processes of S30 to S39 are performed as described above. In S33 and S34, the engine performance can be calculated using the empirical formula generated in S43 and stored in the empirical formula database 38.

Next, a second modification of the second embodiment will be described with reference to FIGS. 16 and 17. FIG. 16 is a schematic configuration diagram of an engine performance analysis system according to a second modification of the second embodiment of the present invention, and FIG. 17 illustrates processing of the analysis system according to the second modification of the second embodiment of the present invention. It is a flowchart which shows a part of flow of content.
This modification is an example in which a processing step for generating an empirical formula by performing multiple regression analysis of past data is added to the processing flow (FIG. 13) in the second embodiment described above, and the analysis model generated in S29 These processing steps are performed when an empirical formula capable of calculating the engine performance is not stored in the experimental formula database 38.

  First, as shown in FIG. 16, the engine performance prediction program 54 of the prediction analysis system 50 according to this modification is obtained by adding an empirical formula generation program 56 to the engine performance prediction program 34 according to the second embodiment shown in FIG. It is. A CFD analysis system 52 according to this modification is obtained by adding a past case database 58 to the CFD analysis system 32 according to the second embodiment shown in FIG. The other programs 10 and the like, the database 20 and the like, and the CAD system 4 are the same as those in the second embodiment, and description thereof will be omitted below.

The experimental formula generation program 56 according to the second modified example is a program that generates an experimental formula based on data stored in the past case database 58. The past case database 58 stores a one-dimensional CFD analysis model of the engine analyzed in the past, its analysis conditions (including operating conditions such as engine speed), and its analysis results. The processing contents by the experimental formula generation program 56 will be further described with reference to FIG.
As shown in FIG. 17, in this modified example, after the process of S29 (FIG. 13) is completed, the process proceeds to S50, and an experimental expression capable of calculating the engine performance of the analysis model generated in S29 is stored in the experimental expression database 38. It is determined whether or not it has been done. If stored, the process proceeds to S30 (FIG. 13), and the processes of S30 to S39 are performed as described above in the second embodiment.

If it is determined in S50 that the empirical formula is not stored, the process proceeds to S51.
In S51, the specification values, analysis conditions, and analysis results of a plurality of analysis models that can perform multiple regression analysis are read from the past case database 58.
Next, in S52, the specification values, analysis conditions, and analysis results read in S51 are subjected to multiple regression analysis, and in S53, an empirical formula is generated from the results of the multiple regression analysis. Further, the generated experimental formula is stored in the experimental formula database 38. After the process of S53 is completed, the process proceeds to S30 (FIG. 13), and the processes of S30 to S39 are performed as described above. In S33 and S34, the engine performance can be calculated using the empirical formula generated in S43 and stored in the empirical formula database 38.

  According to these first and second modified examples, as in the first and second embodiments described above, an optimal and new intake / exhaust configuration can be obtained efficiently. Even in the absence, the empirical formula is automatically generated, so the calculation time can be shortened more reliably.

  As a third modified example, a general rule indicating the relationship between the specification value and the engine performance, for example, a general rule that a thin and long tube and a thick and short tube both have equivalent torque characteristics. Or you may newly provide the general formula database which stored the formula (general formula) which prescribed | regulated the knowledge acquired in the past. By providing such a database, for example, when there is no required empirical formula, the engine performance can be calculated based on the general formula.

1 is a schematic configuration diagram of an engine performance analysis system according to a first embodiment of the present invention. It is a schematic diagram which shows an example of a one-dimensional analysis model. It is a flowchart which shows the flow of the processing content in the analysis system of 1st Embodiment of this invention. It is a schematic diagram which shows an example of the one-dimensional analysis model for demonstrating designation | designated of the connection part which can add or isolate | separate a component model. It is a diagram which shows the evaluation condition pattern of a torque characteristic as an example of the criterion for optimization. It is a schematic diagram which shows an example of the one-dimensional analysis model in which the model structure was changed. It is a schematic diagram which shows an example of the one-dimensional analysis model in which the model structure was changed. It is a schematic diagram which shows an example of the one-dimensional analysis model in which the model structure was changed. It is a schematic diagram which shows an example of the one-dimensional analysis model in which the model structure was changed. It is a schematic diagram which shows an example of the one-dimensional analysis model in which the model structure was changed. It is a schematic block diagram of the analysis system of the engine performance by 2nd Embodiment of this invention. It is a figure which shows an example of the preliminary difference of an experimental formula. It is a flowchart which shows the flow of the processing content in the analysis system of 2nd Embodiment of this invention. It is a schematic block diagram of the engine performance analysis system by the 1st modification of 2nd Embodiment of this invention. It is a flowchart which shows a part of flow of the processing content of the analysis system by the 1st modification of 2nd Embodiment of this invention. It is a schematic block diagram of the engine performance analysis system by the 2nd modification of 2nd Embodiment of this invention. It is a flowchart which shows a part of flow of the processing content of the analysis system by the 2nd modification of 2nd Embodiment of this invention.

Claims (11)

A predictive analysis system that predicts engine performance by analyzing engine intake and exhaust flows using a CFD analysis program,
Analytical model generation means for generating a one-dimensional CFD analysis model based on an operator's input, and a restriction condition and a change in specification values of a model configuration change of at least the intake pipe and / or the exhaust pipe of the CFD analysis model Constraint condition setting means for setting the constraint conditions based on the input of each worker,
Analysis model changing means for changing the CFD analysis model by changing the model configuration and specification values within the set constraints, respectively;
Engine performance calculation means for calculating the engine performance by executing the analysis by the CFD analysis program for the changed CFD analysis model;
Repetitive execution means for repeatedly executing engine performance calculation by the engine performance calculation means for the CFD analysis model changed by the analysis model changing means and the CFD analysis model after the change;
An optimum model selecting means for selecting a CFD analysis model in which optimum engine performance satisfying a predetermined standard is calculated from a plurality of modified CFD analysis models;
A system for predicting and analyzing engine performance, comprising: A predictive analysis system that predicts engine performance by analyzing engine intake and exhaust flows using a CFD analysis program,
Analytical model generation means for generating a one-dimensional CFD analysis model based on an operator's input, and a restriction condition and a change in specification values of a model configuration change of at least the intake pipe and / or the exhaust pipe of the CFD analysis model Constraint condition setting means for setting the constraint conditions based on the input of each worker,
Analysis model changing means for changing the CFD analysis model by changing the model configuration and specification values within the set constraints, respectively;
First engine performance calculating means for calculating engine performance by executing analysis by the CFD analysis program on the CFD analysis model after the change;
An empirical formula database storing empirical formulas that define the relationship between the above specifications and engine performance;
Second engine performance calculation means for calculating engine performance using the empirical formula stored in the empirical formula database for the modified CFD analysis model;
Selecting means for selecting either the first engine performance calculating means or the second engine performance calculating means according to a predetermined condition;
Change of the analysis model by the analysis model change means, selection of the first engine performance calculation means or the second engine performance calculation means by the selection means, and the selected first of the CFD analysis model after the change. Repetitive execution means for repeatedly executing calculation of engine performance by one engine performance calculation means or second engine performance calculation means;
An optimum model selecting means for selecting a CFD analysis model in which optimum engine performance satisfying a predetermined standard is calculated from a plurality of modified CFD analysis models;
A system for predicting and analyzing engine performance, comprising:   The selecting means selects the first engine performance calculating means when the analysis model changing means changes the model configuration and calculates the engine performance for the changed model configuration for the first time, and selects the same model configuration. The engine performance prediction analysis system according to claim 2, wherein the second engine performance calculation means is selected when the analysis model changing means changes the specification value and calculates the engine performance for the second time and thereafter.   Further, when the empirical formula capable of calculating the engine performance is not stored in the empirical formula database for the CFD analytical model changed by the analytical model changing means, the specification value of the CFD analytical model is obtained by the analytical model changing means. The engine performance is calculated by the first engine performance calculation means for each of a plurality of CFD analysis models obtained by changing a plurality of times within a predetermined change width, and the calculated engine performance and the plurality of CFDs. The predictive analysis system for engine performance according to claim 2, further comprising an empirical formula generating means for generating an empirical formula by performing a multiple regression analysis based on the specification values of the analysis model. Further, a past case database that stores CFD analysis models generated in the past and analysis results related to engine performance in the CFD analysis models;
In the case where the experimental formula capable of calculating the engine performance is not stored in the experimental formula database for the CFD analytical model changed by the analytical model changing means, the specification values of the CFD analytical model stored in the past case database and the The engine performance prediction analysis system according to claim 2, further comprising: an empirical formula generation unit that generates an empirical formula by performing a multiple regression analysis based on an analysis result regarding the engine performance in the CFD analysis model.   The engine performance prediction analysis system according to claim 1 or 2, wherein the constraint condition setting means sets at least a range of the length of the intake pipe and / or the exhaust pipe as a constraint condition of the specification values.   The said constraint condition setting means sets at least the connection position and the number of the intake pipe and / or exhaust pipe as the constraint conditions of the model configuration in the model configuration related to the intake pipe and / or exhaust pipe. 2. The engine performance prediction analysis system according to 2. A computer-aided prediction analysis method for predicting engine performance by analyzing engine intake and exhaust flows using a CFD analysis program,
An analysis model generation step for generating a one-dimensional CFD analysis model based on an operator's input, a restriction condition for changing a model configuration of at least an intake pipe and / or an exhaust pipe of the CFD analysis model, and change of specification values A constraint condition setting step for setting the constraint conditions based on the input of each worker,
An analysis model changing step for changing the CFD analysis model by changing the model configuration and specification values within the set constraint conditions;
An engine performance calculation step of calculating an engine performance by executing an analysis by the CFD analysis program for the changed CFD analysis model,
The calculation of the engine performance by the engine performance calculation step for the change of the CFD analysis model by the analysis model change step and the CFD analysis model after the change is repeatedly executed,
Furthermore, an optimum model selection step of selecting a CFD analysis model in which an optimum engine performance satisfying a predetermined standard is calculated from a plurality of modified CFD analysis models;
An engine performance prediction analysis method characterized by comprising: A computer-aided prediction analysis method for predicting engine performance by analyzing engine intake and exhaust flows using a CFD analysis program,
An analysis model generation step for generating a one-dimensional CFD analysis model based on an operator's input, a restriction condition for changing a model configuration of at least an intake pipe and / or an exhaust pipe of the CFD analysis model, and change of specification values A constraint condition setting step for setting the constraint conditions based on the input of each worker,
An analysis model changing step for changing the CFD analysis model by changing the model configuration and specification values within the set constraint conditions;
A first engine performance calculation step of calculating an engine performance by executing an analysis by the CFD analysis program for the changed CFD analysis model;
A second engine performance calculation step for calculating the engine performance using the empirical formula stored in the empirical formula database storing the empirical formula for defining the relationship between the above-described specification values and the engine performance for the changed CFD analysis model When,
A selection step of selecting either the first engine performance calculation step or the second engine performance calculation step according to a predetermined condition,
The change of the analysis model by the analysis model change step, the selection of the first engine performance calculation step or the second engine performance calculation step by the selection step, and the selected first of the CFD analysis model after the change. The engine performance calculation by the engine performance calculation step 1 or the second engine performance calculation step is repeatedly executed,
Furthermore, an optimum model selection step of selecting a CFD analysis model in which an optimum engine performance satisfying a predetermined standard is calculated from a plurality of modified CFD analysis models;
An engine performance prediction analysis method characterized by comprising: A predictive analysis program for an analysis computer that predicts engine performance by analyzing engine intake and exhaust flows using a CFD analysis program,
A one-dimensional CFD analysis model is generated based on the operator's input, and the constraint condition for changing the model configuration and the constraint condition for changing the specification values of at least the intake pipe and / or the exhaust pipe of the CFD analysis model are respectively operated. The CFD analysis model is changed by changing the model configuration and specification values within the set constraint conditions, and the CFD analysis model after the change is analyzed by the CFD analysis program. by running is calculated engine performance, the CFD analysis model changes and the calculation of the engine performance repeatedly be executed for that change after the CFD analysis model, the CFD analysis model after several changes, satisfies a predetermined criterion The above analysis computer so that the CFD analysis model for which the optimum engine performance is calculated is selected. Predictive analysis program of the control to engine performance. A predictive analysis program for an analysis computer that predicts engine performance by analyzing engine intake and exhaust flows using a CFD analysis program,
A one-dimensional CFD analysis model is generated based on the operator's input, and the constraint condition for changing the model configuration and the constraint condition for changing the specification values of at least the intake pipe and / or the exhaust pipe of the CFD analysis model are respectively operated. The CFD analysis model is changed by changing the model configuration and specification values within the set constraint conditions, and the CFD analysis model after the change is analyzed by the CFD analysis program. Either the calculation of the engine performance by executing or the calculation of the engine performance using the empirical formula stored in the empirical formula database storing the empirical formula defining the relationship between the above specification values and the engine performance is performed according to a predetermined condition. is selected, is calculated engine performance based on the selection, changing of the CFD analysis model, C after the modification Calculating engine performance by the CFD analysis program for D analytical model or selected for calculating the engine performance using the above empirical formula, and repeats the calculation of the engine performance based on the selection for CFD analysis model after the change An engine performance predictive analysis program for controlling the computer for analysis so as to select a CFD analysis model for which an optimum engine performance satisfying a predetermined criterion is selected from a plurality of modified CFD analysis models.

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