Continental Automotive GmbH
Continental’s simulation vision is to “Get the Product Right the First Time,” and the company’s strategy to achieve this has been through simulation-based design decisions. As a result, simulation using FloTHERM is now very highly integrated into the design process.
“FloTHERM is a key component of our simulation-based design decisions strategy, ensuring that our thermal design goals are met and we can deliver on Continental’s simulation vision of ‘getting the product right the first time.”
Dr. Uwe Lautenschlager, Continental Automotive GmbH
A World Away from Physical Prototyping The design engineers at Continental undertake full 3D system-level modeling, with all thermally relevant and air flow parts included in the simulation. The geometry representation is based on mechanical CAD data, with export/import of all relevant parts and modules from the CAD system. However, the geometry representation can involve both simplification and idealization. The complexity used depends on the simulation objective: less detail would be used for the analysis of various initial concepts, whereas more details would be included in the model for a mature design. “Know-How” – Continental’s Competitive Edge Continental has developed considerable in-house know-how associated with building and validating thermal simulation models (FloTHERM™ models) of the company’s complex electronic systems and subsystems, covering both the physical hardware, and potential cooling solutions.
Uncertainties arising from the various unknowns at each stage in the design process, modeling assumptions, and simplifications are mitigated through validation, as the following two examples illustrate.
- Tuner-Module Modeling: This can be modeled as a single block with homogeneous power dissipation distribution, as a detailed model with all of the internal electrical components and shielding represented, or anywhere in between. In the experience of Continental’s engineers, a simplified model is often sufficient within a complete system analysis. However, conclusions on the internal component temperatures are drawn from a reference simulation as depicted in Figure 1.
- Chassis Model Verification: A part of the chassis is used as a heatsink for amplifier cooling. An important aspect of the chassis is the extent to which the brackets on the top and bottom covers are in thermal contact (related to manufacturing tolerances). Verification of modeling assumptions is the key to improving model fidelity. Therefore, a prototype of the product was measured and the results used to compare against the simulation model. Scenario 1 (g1) considers the gap to be fully closed (perfect thermal contact), whereas Scenario 2 (g2) has a gap of 0.3 mm, so there is effectively no thermal contact between the covers. By comparison with the measured case temperature, the results for Scenario 2 (with gap) seems to be the best representation of the bracket’s contact.
The focus of Continental’s engineers on simulation does not stop at building and validating thermal models. Design decisions made to improve the thermal design can affect the mechanical, electrical, and EMC performance of the product. Faced with this problem, a major question facing Continental’s design engineers is: “How can we achieve design flexibility and enable better design decisions before the freedom for such decisions is eliminated?” The answer to the challenge requires analysis of the product’s behavior for all disciplines, as well as the identification of independent and coupled system variables. Multidisciplinary design optimization (MDO) techniques with simulation, optimization (with discipline-dependent objectives and constraints) and design-of-experiments (DOE) and response surface methods are suitable means to solve this design problem.
Continental designers have to react quickly to changing customer requirements. Products have to be developed with regards to customer confidence and quality, costs, and design time. MDO has been found to be a suitable means for finding better design solutions in a multidisciplinary environment. Simulation supports knowledge generation and a deeper understanding of product behavior at lower cost, in shorter time and with increased product flexibility, leading to increased customer confidence in their products.
“We selected FloTHERM™ for several reasons but primarily for its robust solution capabilities. FloTHERM’s object-associated Cartesian meshing is instantaneous, fully automatic, and most importantly guarantees a mesh that produces accurate simulation results even when geometry changes are made to the base model.
Dr. Uwe Lautenschlager, Continental Automotive GmbH
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