GM turns to simulations to speed hybrid development

Automotive News reports on how GM develops hybrid vehicles.

Automotive News

General Motors, racing to bring hybrid vehicles to market faster, is turning to simulation to lop weeks off the time required to design and develop software control systems for hybrid power trains.

And it goes beyond hybrids. GM is using technology known as model-based design from MathWorks, of Natick, Mass., to develop software control systems for all new GM power trains around the world.

This software, called Simulink, allows GM to simulate the control system for any GM power train before committing to the hardware.

"I don't think you could do a hybrid control system without model-based design and development," said Kent Helfrich, director of software engineering in GM Powertrain. Hybrid power trains are far more complex than those built around internal combustion engines and require sophisticated software controls.

Hybrid integration
"The name of the game in hybrid systems is integration," Helfrich told Automotive News. "You can't make an engine and a transmission separately anymore and then integrate them at the last minute. This has to be conceptualized as a family, as a system. If the system isn't conceptualized well, your end product's not going to work very well."

The automaker used MathWorks tools to design and develop its Two Mode hybrid power train control system launched in January on the GMC Yukon and Chevrolet Tahoe SUVs.

The Two Mode hybrid control system was done entirely in model-based design, Helfrich said.

"That really enabled engineers to do what they needed to do to ensure that the system actually worked, prior to even having hardware available," he said.

GM is reducing costs and taking weeks out of the development time of control systems for hybrid power trains, he said. The automaker also is shortening its cycle time on design changes without affecting quality, he said.

"We can now do those iterations virtually, and then commit ourselves to hardware later in the design center," Helfrich said. "It saved us a lot of money in terms of eliminated prototypes and rework."

Helfrich declined to quantify the cost and time savings. "It's hard to quantify things that you didn't do," he said. "But we couldn't do it without this. So it's not really a cost avoidance in that it is the only way to achieve what we need to achieve in our integrated power train controls."

Chain of tools
GM is using the same model-based design in engineering centers around the world, he said.

"The key is having one tool chain and one software product line globally for all of GM power train engineering," Helfrich said. "That's kind of unusual."

Just as automakers build a variety of vehicle models on a single platform, Helfrich's team is making those same types of design and architecture choices at a software level, said Jon Friedman, manager of aerospace, defense and automotive industry marketing at MathWorks.

MathWorks' competitors in the market for control system design software tools include Wind River Systems Inc., of Alameda, Calif.; and Mentor Graphics Corp., of Wilsonville, Ore.

GM also has power train control systems that were developed before the availability of model-based design. "That means we've got an interesting combination of old software and new software coexisting," Helfrich said.

"But it's good because the old software's validated and high-quality and is in use in millions of vehicles worldwide. We don't want to replace that unless we absolutely have to."

Companies such as Toyota Motors, Denso, and Delphi also use MathWorks tools to provide a common platform for sharing system specifications and development ideas.

(Source: Automotive News)

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