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Chevy Volt: More Computer Than Car

With more lines of code than it takes the average F-35 fighter fly, the Chevy Volt is on the edge of a shift to automobiles built with, and run on, software.

Henry Ford probably wouldn’t recognize the inside of General Motor’s Chevy Volt because the car is almost more software than hardware.

Powered by a “system of systems,” software makes up over 40 percent of the car -- up from just 5 percent in the 1980s -- which features over 100 electronic controllers, 10 million lines of code, and even has its own IP address.

“With the level of technology that we’re putting into today’s automobile, the product development process is just like a rocket program,” says Eric Cassenfeit, global director of electrical, controls and software development for General Motors. “The Chevrolet Volt is an excellent example of that.”

IBM worked with GM in developing the software systems for the Volt by providing a set of tools to assist with software development, requirements management, and system level design, says Sky Matthews, director of Rational Systems Products at IBM.

“For them, getting their hands around a problem that included so much software content was a new thing,” says Matthews. “They certainly had challenges around the ability to scale their expertise and the quality of their software delivery process.”

A major tool GM used was Rational Rhapsody Architect for Software, an IBM program that was used to design the high-level architecture of the vehicle. Rational Rhapsody has been used in a number of other industries including aerospace, defense, telecommunications, and other automotive applications, says Matthews.

“There has been other uses of those products in automotive in the past as well,” says Matthews. “It’s not new, but certainly this is probably the largest program they were used on.”

The Volt’s heavy reliance on software is reflective of a dramatic change in the automotive design process, says Matthews. For one, software is a flexible platform, meaning it can be changed or modified without needing to recall the vehicle or change the hardware.

“It gives customers -- automotive OEMs and suppliers – more flexibility on how they go about conceptualizing and designing the functionality of the vehicle,” Matthews continues. “The more you can put into software the more flexibility you give yourself as a manufacturer.”

Secondly, it allows vehicles to connect remotely to other products like OnStar or Ford SYNC, which allow for more flexibility in how functions can be delivered to the customer. Electric cars like the Volt could eventually be able to interact with the electric grid or connect with other applications.

“Ultimately as a user of a vehicle, I don’t care whether the processing is being done in a processor onboard the car or somewhere off in an IT farm somewhere else, as long as it makes my vehicle do something cool and interesting,” says Matthews.

Rhapsody was also used in the Volt testing process, providing the rigorous simulations needed to make sure the Volt battery would hold up. The Chevy Volt is powered by a “T”-shaped lithium-ion battery which powers the electric drive unit. This allows it to drive 40 miles on battery power alone. Software simulations helped prove the battery’s safety and durability over three years of validation testing.

IBM software was also used to help speed up time-to-market on the Volt, which was designed and engineered in just 29 months. A relatively new IBM product, Rational Team Concert, helped engineers and designers collaborate in real time, with their work tracked and managed within the program, says Matthews.

“We’ve had some roles within our engineering operations that have had maybe 20 to 40 percent efficiency because they spend the bulk of their time keeping track of all the people interacting and what they’re working on,” says Len Wozniak, manager, Software Process and Powertrain Controls Architecture for General Motors. “It’s horribly frustrating to engineers, it tremendously slows down our development. Our engineering really don’t have to spend their time finding information anymore. When information is available to one, it’s available to all.”

Although the Volt is first car to have such extensive software under the hood, Matthews thinks this is part of relatively recent shift in automotive design.

“For automotive it’s pretty recent that they’ve crossed that complexity barrier and they have to start relying on tools to generate more of the software for them,” he says. “I think that’s going to be a big trend in automotive. The Volt is certainly the most complex automotive project we’ve seen in terms of software so far.”

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