As we strive to meet global emissions targets over the coming decade, technologies which enable a reduction in total vehicle cost whilst improving vehicle performance and design will be critical in driving electric vehicle uptake.
Ricardo’s R&D team recently introduced Project DiODE; innovate oil cooled systems for power electronics and electric machines within an EDU application. Within the DiODE project we are developing an electric motor concept which utilises our innovative oil cooling technologies and advanced thermal management solutions to achieve up to 20% improvement in performance compared with current leading-edge products. This enables a 10-20% motor downsizing and weight reduction which brings down the cost of the vehicle and improves vehicle packaging opportunities.
We spoke to David Hawke, Chief Engineer on the DiODE project to get an insight into how this was achieved and to find out what the next steps are for development of this innovative solution.
Hi David, thanks for agreeing to chat with us today. Can you give us a bit of an insight into the technical objectives for the DiODE project?
David: “For our project we have five key technical objectives. The first was to design novel distributed oil jet cooled Power Electronics, designs, which are compatible with 800 volts, 400 volts and other levels. Our current solution is designed for 800 volts, but there is room to increase that.
The second objective is to innovate and down select cooling approaches for the rotor, the stator and power electronics, looking at direct cooling heat pipes as well as new materials and how they integrate into one system.
The third objective consists of updating our thermal toolchains, improving our modelling, our design tools and bring them even closer together so that we can assess concepts over relevant drive cycles. In this project, we're assessing automotive specifically but the tools and approaches we can apply to any market. We've looked at using them for airspace, we could also use them for off highway and other areas.
The fourth objective is to analyse the different concepts against targets focusing on mainstream passenger car but also scaling to high performance vehicles, trucks and off-highway.
And lastly, our final objective is to develop a concept EDU that operates at 800 volts and is suitable for passenger car applications. This concept can be used to guide global vehicle manufacturers as they develop electric vehicles, helping them to bring their products to market faster, and at lower cost.”
So, what is the desired outcome of the project? Can you highlight some of what has been achieved so far?
David: “We are aiming to have an EDU concept that's ready for development which is customisable for OEMs. So far in the project, we've made great progress in the toolchain development. We're able to cut several weeks out of our development process by streamlining the tools and automating the interactions, particularly between the electromagnetic and thermal. More specifically, we were able to speed up the process of building a 1D thermal model to assess complex thermal designs quickly and earlier in the design cycle.
Another highlight would be that the project is looking at the distributed inverter and this has enabled a huge improvement, saving a lot of package space. We've essentially split the inverter into 3 phase modules so we can package it around the output shaft of the e-machine if we chose, or for a different application we could package it around the outer diameter of the machine as well. But this gives us more options for packaging, enables us to use more dead space within the EDU within the transmission part.”
It sounds like this technology is really going the help OEMs to improve the performance of their vehicles whilst providing them with lots of options in terms of vehicle packaging. What is next for the DiODE project, then? Where do you see the technology progressing?
David: “Well what’s been particularly exciting in this project is that we've seen that a shared oil system for cooling of electrical parts, has the potential to have big advantages.
The conventional approach would be to use a water-glycol cooling system, but that's not compatible with direct contact of electrical live parts. Obviously, water and electricity don't mix! So, we've been able to get big benefits by putting the oil in direct contact with the electrical live parts.
Future work on the project will be validating the direct oil designs, more from a lifetime perspective, looking to extend the analysis into more detailed life analysis of components.
We can then increase the power density of both the e-machine and power electronics, as we understand how hard we can push the components dependent on duty cycle.”
There’s certainly a lot of potential here. We look forward to hearing more as the project progresses!
David: “Yes, DiODE has been a really exciting project to work on. It has brought a lot of key people within Ricardo together to develop an innovative oil cooling and thermal management solution which helps to solve some of the complex challenges facing OEMs today. We're really excited about what we can take in the future!”
Ricardo’s R&D in novel and disruptive cooling technologies and thermal management is already much in demand with global vehicle manufacturers who need innovative technology solutions to accelerate the development and introduction of electric and hybrid vehicles.
Find out how Ricardo can assist you in the development of cooling technologies and thermal management strategies at automotive.ricardo.com/diode