GM Reveals Investment in Fuel-Saving Powertrain Startup

General Motors says it is confident a 3-year-old equity investment in the Silicon Valley startup Tula Technology could soon yield a fuel-economy improvement of up to 15% for some of the automaker’s future cars and trucks.

The companies call it Dynamic Skip Fire (DSF) technology. It integrates advanced digital-signal processing with sophisticated powertrain controls to create a software-based approach to variable-displacement engines, they say, and ultimately makes the most of vehicle fuel economy across a wide range of driving conditions.

“This technology holds the potential to improve fuel economy on select GM vehicles without degrading power capability when it’s required,” GM Chief Technology Officer Jon Lauckner says in a statement.

“This joint effort combines software expertise from Silicon Valley with powertrain expertise from General Motors,” says Lauckner, who also serves as vice president of Global R&D for GM and president of GM Ventures, which made the investment in Tula in 2010.

Co-investors included the venture capital firms Sequoia Capital, Sigma Partners and Khosla Ventures.

Unlike conventional cylinder-deactivation technology, where a fixed number of cylinders are shut down under a relatively rigid set of conditions, DSF continuously makes dynamic firing decisions on an individual cylinder basis to deliver the required engine torque for all vehicle speeds and loads while avoiding vibration issues.

According to Tula testing, DSF has shown a fuel-efficiency improvement of up to 15% in a multi-cylinder engine compared with an engine without cylinder deactivation.

GM’s news regarding DSF comes as automakers speed up powertrain investment to meet tightening global fuel-economy and carbon-dioxide emissions rules, including a federal target of 54.5 mpg (5.2 L/100 km) by 2025 in the U.S.

The automaker says it is revealing the investment in Tula for the first time because DSF has a reached an advanced stage of development.

GM Ventures has invested in about 20 startup companies since it was founded in 2010. Investments generally target early-stage automotive technologies such as clean technology and advanced lightweight materials.

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