Why automotive engineers are struggling with thermal simulation

thermal managementWith increasingly complex and compact designs, more electrical features and greater connectivity, today’s vehicles are a thermal management minefield, says Chris Aldham, product manager at Future Facilities Ltd.

More than ever before, thermal management is an essential part of automotive electronics design. With each new component, the heat output grows and the risks of thermal complications increases.

Now, with electric and even autonomous vehicles on the horizon, these complications are only set to increase.

For automotive engineers, this means a renewed focus on thermal management and the need for increasingly advanced thermal simulation software to test and measure their designs.

Computational Fluid Dynamics (CFD) software is a staple of the automotive industry, being used to test the reliability, safety and efficiency of electronics components and devices without building a physical prototype.

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While simulation is vital for this industry, recent research has shown that many automotive engineers aren’t happy with the functionality of their current CFD platforms. According to 6SigmaET’s 2021 survey of thermal engineers — which examined users of the top five simulation platforms — 30 per cent of those working in the automotive sector are dissatisfied with the modelling capabilities of their thermal simulation platforms.

So, why the disconnect?

Automotive electronics design is an extremely fast-moving industry, with many CFD software’s failing to meet evolving requirements and changing industry trend.

To understand these trends. 6SigmaET recently hosted a roundtable of automotive electronics engineers, who identified three key automotive innovations that are causing problems for thermal management in 2021:

1. The switch to electric vehicles

While great news for the planet, the move to electric vehicles (EVs) is leading to a whole host of complications for thermal design. Most EV’s use lithium-ion batteries that are a lot more sensitive to temperature changes than fuels used in non EV’s. Furthermore, power electronics components that are traditionally used to transmit power from batteries to the motor are very thermally sensitive. With elevated temperatures, there’s a far higher risk of ‘thermal runaway’.

To address these issues, CFD platforms are needed that can provide models for these new, more complex components. Currently, many such models must be designed from scratch — an extremely time-consuming operation.

2. Compact electronics

Where once vehicles were simply a means of getting from A to B, today they are also equipped with integrated features that incorporate a whole host of safety, security, luxury, connectivity and entertainment technologies.

As all of this tech gets built into the relevant microcontrollers, the designs grow more complex and less spacious — inevitably resulting in greater heat output and the potential for unexpected thermal complications. As a result, engineers must rethink things like layouts, airflow designs and cooling mechanisms in order to keep up with the latest automotive designs.

And it’s not just size that’s causing problems, the aesthetic nature of automotive design means that electronics components must also be squeezed into a baffling array of curved casings and designs. This pushes components together and leaves little room for bulky cooling mechanisms and unobstructed airflows.

To address this, CFD platforms must be able to import, handle and solve the complex geometries involved in automotive design, where electronics are designed to fit into the limited space available. Unfortunately, this is something that many legacy thermal simulation tools still struggle with.

3. Autonomous vehicles

The rise of experimental, autonomous vehicles has added a whole host of new challenges to the process of thermal management — further stretching the capabilities of many traditional CFD softwares.

To function safely and effectively, self-driving cars will need to incorporate hundreds of new electronic components including perception sensors, high-performance processors and decision-making AI hardware. All of these new components will have a significant impact on thermal management, with newer, more powerful chipsets expected to have a much higher thermal output.

With ever more electronics being added, engineers are being forced to rely on newer cooling mechanisms designed for a tightly packed environment. Increasingly, this will mean the incorporation of liquid cooling techniques as well as thermal solutions that are highly integrated within the mechanical packaging design.

Today, thermal simulation tools are rapidly evolving to meet these changing needs. The best simulation platforms are offering the ability to import complex CAD geometry and “photorealistic” ECAD, allowing them to recreate the complex form factors used within automotive design. Some are now also providing tools that can solve at an extremely granular level, identifying potential thermal issues among increasingly advanced and densely packed electronics designs. These types of features are ideal for the automotive environment.

Where once engineers were stuck with the simulation platform they had always used, now the market is becoming increasingly flexible. The introduction of cross-platform file formats such as ECXML means that automotive engineers are no longer “locked in” to a single outdated platform. As a result, it’s easier than ever to switch to a thermal simulation software that supports new design trends and evolving designer needs.

Chris Aldham, product manager at Future Facilities Ltd