WO2004081682A1

WO2004081682A1 - Method for designing and constructing complex technical products

Info

Publication number: WO2004081682A1
Application number: PCT/AT2004/000087
Authority: WO
Inventors: Herwig Sorger
Original assignee: Avl List Gmbh
Priority date: 2003-03-14
Filing date: 2004-03-11
Publication date: 2004-09-23
Also published as: DE112004000118D2

Abstract

The invention relates to a method for designing and constructing complex technical products, especially internal combustion engines, and the components thereof, whereby aids for computer-assisted engineering work are used for the simulation and design, and aids for computer-assisted construction are used for the construction.

Description

Process for the design and construction of complex technical products

The invention relates to a method for the design and construction of complex technical products and their components, in particular internal combustion engines, tools for computer-aided engineering work and tools for computer-aided design being used for the simulation calculation, and program logic for carrying out the method.

It is an existential task for the manufacturers of motor vehicles to meet the rapidly changing market trends with ever shorter model cycles despite increasing cost pressure. It is therefore extremely important to achieve an optimum for a new engine development with regard to the requirements regarding efficiency and performance as well as the safe compliance with the legal and / or market conditions. In addition, the requirements regarding manufacturability and robustness in practical use have to be met in order to make the product competitive. These requirements must be implemented in development projects that provide less and less time for development work in order to open up the market as quickly as possible.

The object of the present invention is to change the development and construction process for a complex technical product in such a way that all the requirements mentioned can be met reliably and in compliance with high quality standards in a given time frame.

According to the present invention, the solution to this problem is seen in the following steps:

a) Filing of development-specific information in at least one

Knowledge Base,

b) defining the product requirements,

c) Creation of a product structure with the aid of computer-aided

Construction (CAD),

d) selecting a model structure from the tools of computer-aided engineering (CAE), e) transformation of at least some of the parameters of the product structure to the model structure,

f) simulation and calculation of at least part of the model structure of the

Product or component based on the transformed parameters of the product structure,

g) transforming the updated parameters of the model structure back to the product structure.

At the interface between geometry definition and simulation, the problem arises that the product models designed in a CAD system (CAD = Computer Aided Design) and the model structures used for the various CAE calculation tools (CAE = Computer Aided Engineering) would have to match, to allow a simple automated exchange of data. However, a simple analysis already shows that the model structure required in the simulation systems does not correlate with the product structure that is present in CAD systems and PDM systems (PDM = Product Data Management). Through the transformation of the parameters from the product structure into the model structure and the back transformation, a correspondence between calculation and construction models can be achieved.

In the case of highly complex products in particular, it is advantageous if, after the product requirements have been defined, they are divided into sub-requirements, the sub-requirements preferably being functionally coordinated with one another. Subsequently, it is provided that sub-models to meet the sub-requirements are selected from a predetermined group of aids for computer-aided engineering work. The submodels can be assigned to individual subrequirements. By merging the partial models into a digital model structure, a development model for the entire model can be generated.

In order to be able to carry out a parameterized control of the product, for example an entire basic engine consisting of the main assemblies cylinder crankcase, crank drive, cylinder head, valve train and timing drive, it is provided that the product properties and / or requirements are defined by control parameters.

For comparison and assessment of equivalent production methods within the process chain, it is particularly advantageous if individual production steps of a component are mapped. Depending on the complexity of the component and the manufacturing and machining process, different model strategies can be used. Another version The invention provides that the product is subdivided into main assemblies within the product structure and that each main assembly is assigned a main skeleton part with auxiliary geometric elements. In this way it is possible to define the structure of a construction by means of relationships between basic geometric elements at a lower level and between components at a higher level, and to automate a construction process even when the parameters of these relationships change. This approach allows you to build a rough design that can be refined step by step without breaking relationships.

The invention is explained in more detail below with reference to the figures. Show it

1 is a flowchart in the overall development process of a product,

2 is a block diagram of the interface integration simulation design,

3 shows a valve train of an internal combustion engine with calculation-specific orientation points,

4 shows a networked rocker arm with orientation point information,

Fig. 5 shows a communication scheme at the interface CAD / CAE and

Fig. 6 shows a construction method for an overall engine.

The key point of the method and sequence optimization described in detail below is the digital product model, which replaces simple models consisting only of 2D or SD geometry and, in addition to the geometry, records all data that arise during the different development phases. The inevitably resulting flood of data requires complex systems for data storage, such as EDM (Engineering Data Management) and PDM (Product Data Management).

The method according to the invention is described using an internal combustion engine. The process is of course also suitable for other complex technical products.

Against the background of the current expansion of the model diversity of vehicle manufacturers and the associated combination of gas exchange and combustion technologies with existing and new engine series, the flexibility of newly created processes and methods is of great importance tion to. The determination of the main engine dimensions requires strategic considerations for the staggered displacement and the determination of the number of cylinders and designs, which must be mapped in the design methodology. In addition to optimizing the construction time and increasing the quality, the goal of new design processes is the adaptability and reproducibility of the boundary conditions. Furthermore, there should be the possibility of directly using concepts for the layout and detail phase as well as for simultaneous and subsequent processes, thereby streamlining the overall development process.

All measures serve to create the necessary quality in order to achieve the high degree of structural maturity in one step, which enables the elimination of a motor generation.

Accordingly, the following 3 priorities can be derived for implementation:

• Metamethodology

• Building methodϊk

• Sequence optimization by using the feature technology

Metamethodology is a general approach, the scope of which should be independent of the CAD / CAE tools used. The metamethodology comprises 5 sub-aspects that also interact:

o Knowledge databases / specifications

• Modularization and frontloading

• control parameters

• Production equivalence

• Interface integration

Since the majority of the constructions are not created without a model ("new construction of the first type"), but rather through the configuration and / or combination of already known full or partial solutions ("new construction of the second type"), the structure and implementation of development and Knowledge databases are of central importance for the use of experience that has already been gathered, on the one hand to make the knowledge of experienced employees who already use the portability of past and known solutions available, and on the other hand to generate specifications that describe the properties of known components as precisely as possible In this context, the requirements are based not only on the product but also on the integrated computer-assisted process chain. This avoids unwanted iterations in the overall development process. The basis for this object orientation are EDM and PDM systems, which must be platform independent and can be used across project phases.

The original possibility of the construction methodology, for correction purposes, to return to certain points in the course of the construction process without leaving the basic sequence of processing, is replaced by new, partly systematic, partly chaotic procedures based on partial models and digitized product models. The basic requirement for this is the modularization of the product in subtasks and the description of the relationships between these subtasks. Through intensive frontloading (Fig. 1), the subtasks can then be optimally interlinked in the sense of concurrent engineering. 1, the degree of development E and the input I are plotted over the development time t. Reference numbers 1 to 4 denote the individual development phases of concept study, pre-development, series development and series assurance. The process of the so-called front loading, that is to say bringing forward the introduction of development-specific information, is indicated by the arrows P.

The development of sensible sub-models for complex main engine components and their combination into a digital product model enables the component properties to be clearly controlled in accordance with the technical requirements (e.g. function, package, manufacture, assembly, customer service, testability, etc.). The control is carried out by control parameters that are derived from the component specifications or specifications. The goal is the parameterized control of the entire basic engine, consisting of the main assemblies cylinder crankcase, crank drive, cylinder head, valve train and timing drive.

The control parameters of the individual main assemblies are hierarchically subordinate to the strategic considerations, such as staggered displacement, determination of the number of cylinders, designs, etc. This clear reference flow enables "top-down" control and prevents sources of error through circuit references. The number of control parameters is deliberately limited so that the main motor functions can be displayed on the one hand, and rapid and reliable changes on the other hand Parameters summarized in sets.

The basis for a continuous process chain is the mapping of the individual production steps of a component, depending on the complexity different model strategies of the component as well as the manufacturing and machining process are used.

At the interface between geometry definition and simulation, the problem arises that the product models designed in the CAD system and the model structures used for the various CAE calculation tools would have to match in order to allow an easily automated exchange of data. However, a simple analysis already shows that the model structure required in the simulation systems does not correlate with the product structure that is present in CAD systems and PDM systems. Accordingly, the integration of the interfaces in the construction method approach CON is essential. Fig. 2 shows schematically the way to integrate the model requirements from the various simulation areas of computer-aided engineering CAE into the CAD model in such a way that on the one hand there is a correspondence between the function-describing control parameters SP, and on the other hand there is the possibility of mutual communication when these control parameters SP change , The design methodology CON is influenced both by the control parameters SP and by bilateral output variables BO. The tools of the computer-aided engineering work CAE consist for example of accompanying calculation CAC, thermodynamic calculation TDA, finite element method FEA, flow dynamic calculation CFD and acoustic calculation ÄCA.

While simulation tools from the field of CFD (Computational Fluid Dynamics) and FEA (Finite Element Analysis) can directly benefit from the advantages of 3D geometries for the creation of their input data, the difficulty with other tools increases even further, since the for Some CAE calculation tools sometimes require geometry-based data to deviate significantly from the geometric information inherent in an element of the product structure. A characteristic of some simulation tools used in the concept phase of the development process is that they have a very high degree of abstraction. This is partly the case because less information is often available for the definition of basic design features, so it does not have to be calculated very precisely, but short throughput times are of great importance for fast optimization.

A known CAE tool, for example, is used for the dynamic calculation of valve and control drives of internal combustion engines. It is used in the earliest concept studies and is used with increasing engine maturity with increased detailing in terms of modeling and data. A calculation of the single valve started and, with satisfactory results, proceeded to the full valve train calculation. This is followed by a further increase in complexity with the addition of the control drive or the drive of injection elements.

For example, one of the parameters that influences the dynamics of a valve train from the start is the rocker arm stiffness.

It can initially be estimated with simple approaches, but with increasing constructive design, an exact determination should be made. So far, either replacement models had to be used or the calculator underwent the tedious process of determining the equivalent stiffness using an FE calculation. In many cases, both a different methodology and different tools were used.

The aim in the example above is to automatically map the CAD model structure or its data to the CAE data model. The solution shows that in addition to the need to assign components and transfer their parameters appropriately, methods must also be selected and parameterized that are used to determine the required data.

This finding quickly leads to the need to dispense with the ideal of fully automated transformation of such data. The closest solution to this is to find a way for a definition activity to be performed only once within the framework of a methodology definition. Since, for reasons of generality, a procedure is required here in which calculations such as FE analyzes are not carried out within a CAD system, but instead have to run outside in the sense of a definable tool chain, only parameter definitions and the construction of calculation-specific model structures are possible. In addition to the representation of the valve train 10 with rocker arms 11 for gas exchange valves 12, FIG. 3 also shows a number of additional orientation points PNTO, PNT1, PNT4, PNT5, PNT6, PNT12, PNT13, PNT14, PNT15, PNT22, PNT24, PNT25, PNT29 , APNTO, APNT1, APNT2, which were assigned to the valve train as part of a methodology. This means that they are retained even if the design is changed. This fact can be used here to easily determine the rocker arm stiffness over the cam angle. With the orientation of these orientation points in addition to the component geometry, for example in the form of a data file in STL format (stereolithography format), the representation as shown in FIG. 4 succeeds when the correct coordinate system is taken into account. Here you can already see the automatically networked component and the orientation points PNTO, PNT2, PNT12, necessary for the storage or application of the load, APNT1 for location and direction. The matching nodes can then be found easily.

In general it can be said that it is also possible to determine complex derivations of data from components or assemblies. This creates an intermediate layer that provides the required methods (FIG. 5) and manages these with regard to their parameters. In this way, all geometry-based data of the CAE data model can be obtained, provided that it was determined using methodical and automatable approaches.

A CAD data exchange layer, e.g. as part of a CAD management system, provides the information in the CAD / CAE interface and manages access and communication. Since the development process is iterative, the calculator or his tool needs direct access to the design to quickly optimize the component shape. He can carry out parameter studies in a simple manner and without involving the designer. However, this is always done in a system that allows the configuration to be adopted when released by the designer.

The set-up methodology takes into account the requirements of the metamethodology, but refines the level of detail in terms of practical implementation so that the scope depends on the CAD tools used. The construction methodology makes it possible to define the construction of a construction by means of relationships between basic geometric elements at a lower level and between components at a higher level, and to automate a construction process even when the parameters of these relationships change. This approach allows you to build a rough design that can be refined step by step without breaking relationships.

The construction methodology should meet the following objectives:

- Bundling of the know-how built up over years regarding 3D CAD modeling

- Coverage of the most common engine configurations (in-line engine, V-engine, any number of cylinders)

- Consistently uniform scheme of the model structure in order to enable every designer to rework models that are also unknown to him

- Multi-modeling ability to work on complex parts and assemblies - Full exploitation of the parametric possibilities of the CAD system with focus on the use of standardized structures to accelerate the model construction and the model change, especially in the concept phase

- Clear definition of the reference flow between the individual engine components

- Independence of the individual main engine assemblies so that the design methodology can also be used in projects in which only a few components need to be designed.

- Largely automatic generation of:

• derived models for component simulation

• simplified DMU models (digital mockup) for installation examinations

• Interface parts to control the functional interaction of the components

The construction methodology is described in more detail below.

The basic structure of the overall engine is carried out via several main assemblies (crank mechanism, crankcase, cylinder head, valve train, timing mechanism), each of which contains its own main skeleton part. This main skeleton part contains all auxiliary geometries (axes, planes, etc.) that are necessary for the components of the respective main assembly and serves as the top reference for these components.

The motor skeleton assembly MSBG is the key element of the applied design methodology. All main skeletal parts HSGM, HSMA, HSKG, HSKT, HSZK, HSVT, HSST are integrated in it. Within the motor skeleton assembly MSBG, the construction parameters PSl to PS7 are exchanged between the individual main skeleton parts via assembly relationships. Since only parametric values are exchanged at this assembly level and no copying geometries are allowed between the individual main skeleton parts, each of these main skeleton parts can also exist on its own. In order to avoid redundancies, a comparison of the parameter values PSl to PS7 is enforced in the motor skeleton module MSBG so that all main skeleton parts functionally and logically match each other.

Main skeleton parts are available for the following main engine assemblies:

1. Overall engine HSGM, HSMA

2. HSKG cylinder crankcase

3. HSKT crank mechanism 4. HSZK cylinder head

5. Valve train HSVT

6. Control gear HSST

Each main skeleton part is completely independent and contains all the reference geometries relevant to it in the form of curves, planes, axes, points, coordinate systems, etc.

The corresponding design parameters are then derived from the respective reference geometry elements and transferred to the other main skeleton parts.

The reference geometry elements are then passed on directly to the sub-skeletons or components via copy geometries in order to ensure a clear "top-down" reference flow.

For some construction elements, a satisfactory solution that contains all the desired variabilities cannot be implemented using parameter control alone. In this case, table-controlled patterns are used, the values of which are parameter-controlled again via relationships.

The main skeleton part and the relevant component skeleton are basically integrated into each assembly. The copy geometries created in the assemblies refer from the main skeleton part to the component skeleton. All other parts in the assemblies only refer to the component skeleton and must be independent of the main skeleton part.

The assembly itself consists of all relevant parts such as cast cores, unfinished parts and finished parts as well as attachments that belong to the assembly. This makes it possible to design several people on one assembly at the same time ("multi-modeling"); the maintenance of the correspondence of the interface references is nevertheless guaranteed.

Universally applicable drawing views and sections are generated from the finished parts and the assemblies, which contain all functionally relevant information.

In the past, conventional CAD systems have focused almost exclusively on the acquisition and processing of shape-describing features using geometric primitives such as points, edges, surfaces and volumes. In contrast, so-called "features" are an extended class of elements that carry more than just geometric information: they are construction elements that, in addition to their geometric description (shape features) also contain information about their behavior in construction (semantics). As a result, development results can be recorded, information for later development phases can be derived semi-automatically and aspects from later phases can be brought into the development process as early as possible. Accordingly, in addition to the parameters described, features serve to integrate other CAE tools and thus streamline computer-aided process chains.

By default, such features only depict relatively simple elements such as standard parts, slugs, ribs, etc. The first attempts to extend this methodology to more complex components exist. The ultimate goal is to extend the feature technology to highly complex components. Here, not only simple parameters such as diameter, length etc., ie scalar sizes, are used for the design of the shape features, but so-called "curves", ie higher-quality geometric elements. This allows even complex bodies to be built up without having to subsequently carry out manipulations that change the topology.

With regard to the design and optimization of the CAD / CAE interface, it is essential that these features can be used to generate a significant part of the parameters for the subsequent derivation of CAE calculation-specific data models. In addition, there is the option of deriving the response from the calculation, e.g. a proposed change to be able to work in without having to interrupt the construction work until the reply is received. This procedure allows a reduction in the mutual time dependency of development activities (sequences) and thus a more compact process design.

The patent claims submitted with the application are proposals for formulation without prejudice for the achievement of further patent protection. The applicant reserves the right to claim further features previously only disclosed in the description and / or drawings.

Back-references used in sub-claims indicate the further development of the subject matter of the main claim through the features of the respective sub-claim; they are not to be understood as a waiver of the achievement of independent, objective protection for the characteristics of the related subclaims.

However, the subjects of these subclaims also form independent inventions which have a design which is independent of the subjects of the preceding subclaims. The invention is also not restricted to the exemplary embodiment (s) of the description. Rather, numerous changes and modifications are possible within the scope of the invention, in particular such variants, elements and combinations and / or materials, for example by combining or modifying individuals in conjunction with those described in the general description and embodiments and the claims and in the drawings Features or elements or process steps contained therein are inventive and lead to a new object or to new process steps or process step sequences through combined features, also insofar as they relate to manufacturing, testing and working processes.

Claims

GODFATHER CLAIMS

1.Procedures for the design and construction of complex technical products, in particular internal combustion engines, and their components, wherein tools for computer-aided engineering work and tools for computer-aided design are used for the simulation and calculation, with the following steps:

a) storing development-specific information in at least one knowledge database,

b) defining the product requirements,

c) creating a product structure with the help of computer-aided design,

d) selecting a model structure from the tools of computer-aided engineering work,

e) transformation of at least some of the parameters of the product structure to the model structure,

f) simulation and calculation of at least part of the model structure of the product or component based on the transformed parameters of the product structure,

2. The method in particular according to claim 1, characterized in that after defining the product requirements, these are divided into sub-requirements.

3. The method in particular according to claim 2, characterized in that the partial requirements are functionally coordinated with one another.

4. The method in particular according to claim 2 or 3, characterized in that sub-models to meet the sub-requirements are selected from a predetermined group of aids for computer-aided engineering work.

5. The method in particular according to claim 4, characterized in that the partial models are brought together to form a digital model structure of the product.

6. The method in particular according to one of claims 1 to 5, characterized in that the product properties and / or requirements are defined by control parameters.

7. The method in particular according to one of claims 1 to 6, characterized in that individual production steps of a component are mapped.

8. The method in particular according to one of claims 1 to 7, characterized in that the product is subdivided into main assemblies within the product structure and a main skeleton part with auxiliary geometric elements is assigned to each main assembly.

9. Program logic for performing the method according to one of claims 1 to 8.

2004 03 11 Fu / Ka