Case Studies

BYD Auto Company Limited

LMS Engineering services helps leading Chinese new energy automotive manufacturer boost hybrid NVH performance.

The right to drive in Metropolis
Imagine not being able to drive to work on Thursdays because your license plate ends in the number eight. Driving into town with a diesel is out of the question entirely. If you don’t own a vehicle yet, odds of ever acquiring a license are no longer based on the ability to drive, but rather on mere chance.

Most of China’s financial and commercial centers have to deal with this unpleasant situation. Number policies, yellow labels for diesel cars and license lotteries are institutionalized practices to try to combat pollution and global warming. On so-called red alert days, driving into town becomes nearly impossible altogether.

Boosting the new energy image
China is doing more than just road space rationing. Since 2009, both the public and private sectors have made it their business to seize the new energy vehicle market. Today, the country has established itself as one of the world leaders in plug-in electric vehicles, representing 15.7 percent of the global light-duty plug-in market. However, new energy vehicles are considered less popular than fuel-driven cars. This fact is not about price alone. The Chinese government heavily subsidizes the hybrid and plug-in industry.

Looking at the hard numbers as well as customer feedback, certain Chinese automotive manufacturers are starting to realize that hybrid and electric vehicles still don’t match their fuel-powered equivalents in terms of quality. Typical noise, vibration and harshness (NVH) issues unique to eco-friendly hybrid powertrains seem to compromise public perception. Effectively resolving these issues requires advanced model-based systems engineering (MBSE). Basically, this methodology frontloads all vehicle subsystems early in the design process to save the most important resources: time and money.

Made in China
The MBSE approach to car development in China still lags behind. As a result, the luxury car market is dominated by the big, often European brands. Wealthy Chinese customers seem to prefer smooth and silent BMW or Mercedes-Benz sedans rather than the national alternatives. To change this, Chinese brands are starting to look beyond mere partnerships with established Western brands. Many are starting to go it alone. However, to enter the popular luxury vehicle market, they need to rethink their current outdated and deeply embedded development processes.

BYD Auto Company Limited is one of China’s pioneers in hybrid and full-electrical vehicles. Although the company only entered the automotive industry in 2003, the BYD car brand is gaining in popularity. With seven major industrial bases in Xi’an, Beijing, Shenzhen, Huizhou, Shanghai, Changsha and Shaoguan, BYD Auto Company Limited has world-class car manufacturing capabilities.

Determined to close the gap
To maintain a leading position in electric vehicles and meet ever-increasing customer expectations, BYD management approached Siemens PLM software. Shortly after, Siemens PLM Software’s LMS™ Engineering was given a clear mandate to improve the overall NVH performance of the BYD plug-in hybrid vehicle fleet.

“Customer requirements on noise and vibration in new energy vehicles are becoming demanding and we still had some issues to tackle before our cars could break through,” says Zhang Rongrong, manager of the NVH technology research division of BYD Auto Company Limited. “We specifically selected LMS Engineering to help us with these problems because we were impressed with the wealth of NVH technology accumulated over the years.”

Benchmarking and target setting
Before anything else, an engineer needs working data. Zhang Rongrong knew that the key to improving the overall NVH performance in the BYD hybrid vehicles was an in-depth understanding of the requirements. Knowing exactly where and precisely how much a car lags behind the competition would be crucial to resolve any discrepancies. A benchmarking approach was applied to the Qin, where the BYD prototypes were put nose to nose with comparable competitor models, providing all required data to execute a targeted optimization campaign.

In the next step, test-based results were analyzed using LMS Test.LabTM software. The results gave the team a basic understanding of the NVH issues to resolve. A more detailed objective evaluation followed to set the targets. Next, a detailed diagnosis provided a shortlist of possible solutions. After considering the impact on the subsystems, BYD reached a verdict regarding the solutions it wanted to implement while taking particular care to ensure that other vehicle performance attributes, such as handling and durability, did not deteriorate.

Tangible results
Highly targeted development loops executed by the LMS Engineering team helped BYD boost the NVH performance of Qin model prototypes significantly. Rongrong notes, “The results we got were staggering. Not only did we succeed in complying with our prior-defined targets, sometimes we even managed to surpass the NVH performance of the benchmark. For the Qin, idle noise in HEV mode came in at 0.9 dBA (A-weighted decibels) less than the target. This result was also 3.7 dBA less than the starting level, and 3.4 dBA less than the competing vehicle.

“Fifteen versions of the Qin were praised for NVH performance by our customers. Working together with LMS Engineering for NVH optimization has helped us position ourselves as the top seller in plug-in new energy vehicles. Thanks to LMS Engineering, we managed to save a considerable amount of time and resources. We were also able to boost our overall brand value and reputation.”

Taking the engineering leap
At present, LMS Engineering is working together with BYD’s NVH performance research division to optimize its latest hybrid model, the Song. For this one, the stakes have been raised and BYD is taking the engineering leap. The company is rethinking its current, deeply rooted vehicle development process, which is largely based on prototype benchmarking and troubleshooting. Instead, BYD wants to move into the world of model-based systems engineering, where requirements can be frontloaded in the very early phases of product development at a much lower cost. Initial benchmarking, which delivered outstanding results for the Qin, will soon be part of a larger, more advanced optimization process. As a standalone technology, it remains indispensable for the moment as it delivers essential test data for advanced and efficient system simulation.

Ready for the future
“With LMS Engineering, our NVH performance development and control process has significantly improved,” notes Rongrong. “The majority of noise- and vibration-related issues are now dealt with early in our product development process. The entire procedure is much more integrated.”

With this fundamental change in philosophy, BYD Auto Company Limited has attributed NVH performance its rightful place within the design cycle of future vehicles. The company has taken a significant step in the race to compete with other hybrid luxury car manufacturers outside of China.

Rongrong concludes, “We will definitely keep collaborating with LMS Engineering within the field of NVH as well as other key performance areas. Next to their technical strength, we were especially satisfied with the expert’s open and cooperative attitude, professionalism and dedication.”

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