Using blocked force methodology to reduce development time by 50 percent for BEV compressor manufacturers

Adapting to the electrical transition

As component noises become more noticeable without engine sounds to mask them, the quieter operation of battery electric vehicles (BEVs) presents noise, vibration and harshness (NVH) challenges throughout development. Compressors are particularly problematic because they produce constant tonal noise unrelated to acceleration. In addition to noise and vibrations, integrating components is also more challenging. The electrical compressor is now part of the powertrain unit since it is responsible for the thermal management of the battery and powertrain in addition to its usual role in vehicle cabin comfort. As a result, original equipment manufacturers (OEMs) and component manufacturers must adapt to developing the best products in the most efficient way possible.

Sanden is a leading innovator of automotive thermal system products, focusing on quality and environmental sustainability, and has worked with Simcenter™ software solutions for over 20 years. Thomas Di Vito, head of research and concept development, explains the move from a mechanical compressor to an electrical compressor has required the company to adopt new processes.

“Previously, cabin comfort was the priority,” says De Vito. “But now we must focus on the entire thermal management system as cooling is vital for the battery and electronics. On top of this, we no longer have a combustion engine to mask the noise, so it needs to be as quiet as possible without sacrificing any efficiency or effectiveness.”

As well as having an efficient NVH design, the e-compressor must also be compatible with more sustainable per- and polyfluoroalkyl substances (PFAS) free refrigerant solutions. Carbon dioxide (R744) and propane (R290) solutions are much more environmentally friendly, but they require a more complex design to safely handle higher pressure and flammability.

To meet these challenges and stay ahead of the competition, Sanden has adopted cutting-edge techniques to ensure it fully captures customer requirements and delivers the best product for each vehicle. Sanden uses Simcenter SCADAS™ hardware, Simcenter Qsources™ hardware, and Simcenter Testlab™ software for data collection and analysis during the development of these critical components. Simcenter is part of the Siemens Xcelerator business platform of software, hardware and services. Additionally, Sanden provides solutions for new refrigerants carbon dioxide (R744) and propane (R290).

Blocked force methodology

To successfully exchange data with customers to ensure the right products are developed, Sanden needed to align the data format with them to make it as seamless as possible. However, as Olivier Aubry, NVH specialist at Sanden explains, this wasn’t straightforward. “We have many different models of compressor,” says Aubry. “Some with three fixation points, some with four. This means the receiver on the test bench where the compressor is mounted must be changed depending on the model.”

To overcome this, Sanden adopted blocked force methodology to characterize the vibration sources in the context of structure-borne noise. “Previously, using contact forces for transfer path analysis, all the NVH data that was gathered was dependent on the receiver,” says Aubry. “One reason for using Simcenter is that it is very advanced in structure-borne noise determination and blocked force methodology in particular. The Simcenter impact measurements and modal analysis are more advanced than alternative solutions we reviewed. This allows us to gather data independent of the receiver, so it’s the same across all our compressor models.”

Marc Servagent, NVH test engineer, explains how using Simcenter Qsources along with blocked force methodology enables virtual testing of products. “With blocked force methodology we use an invariant load to simulate the response of the compressor in a virtual environment,” he says. “We can define the exact position of the accelerometer and the hitting point on the compressor. Depending on the area we want to excite, it can be difficult to find the space to use the hammer. In this instance we use Simcenter Qsources, which gives reliable excitation. Once we have the necessary data we can easily compare this with a compressor with three or four fixation points.”

Virtual prototyping enhances OEM integration

Effectively integrating the compressor into the full vehicle is just as important as the compressor design itself. Since vehicles have so many variables, the same compressor can perform differently in each. In the past, this would only be realized once prototypes were built, leading to costly redesigns. Now, Sanden gives the customer all the necessary data to add the compressor into a virtual system assembly and simulate performance before building anything. “The interface description at component attachment points is much more advanced with blocked forces methodology,” says De Vito. “Without it, we wouldn’t be able to give customers all the necessary data. But now we can give them a full understanding of our product and how best to integrate it with their vehicle.”

Cutting development time by 50 percent

The new process has proved to be a significant time saver as well as ensuring the accuracy and quality of designs. “Thanks to Simcenter, we have cut development time in half and saved hundreds of thousands of euros by avoiding additional development cycles.” says Di Vito. “We have a product ready to be installed in the vehicle without any further testing as we have already confirmed exactly how it will perform.”

Additionally, Simcenter has aided Sanden and its customers in meeting their environmental targets. It has been used to help build products that not only meet performance requirements but also use environmentally friendly refrigerants, contributing to the overall sustainability of the vehicles they are installed in.

Aubry highlights the contribution of Siemens staff throughout the implementation. “Simcenter customer support and Simcenter Engineering and Consulting services were very important to our success,” he says. “They were quick to respond to any issues we had and worked alongside us whenever we needed them.”

Another reason for choosing Simcenter is the flexible token licensing system that means customers don’t need to invest in specific licenses for modules that would sit idle when not in use. Instead, available tokens can be used for any of the Simcenter Testlab solutions. This allows Sanden to maximize their investment and minimize idle licenses.

Aubry also explains the technology has delivered results beyond those seen directly by customers. “As well as ensuring we can provide accurate information for customers, using blocked force methodology with Simcenter is also of great benefit to us internally,” he says. “It allows us to compare all the data measured at different Sanden sites worldwide, whatever type of test bench and receiver they use, and it enables us to benchmark our products against competitors. This is crucial for maintaining a leading position in the market.”

Reducing noise in the future

Next, Aubry intends to address the airborne and fluid-borne noise generation mechanisms of the compressor. He is confident that Simcenter solutions will play a vital role in this, making sure Sanden maintains its position at the leading edge of component development.