TRAVERSE CITY, MI – Three top powertrain experts mostly see eye to eye on what the future of the auto industry will look like in the next decade or two, with a few notable exceptions: light-duty diesels and extended-range electric vehicles.

On hand here at the CAR Management Briefing Seminars, executives from Ford Motor Co., General Motors Co. and Robert Bosch LLC agree the internal-combustion engine will remain dominant for the next 10 to 20 years, even as alternative electric, hybrid-electric, plug-in electric and extended-range electric vehicles gain ground.

Stop/start technology will be implemented much more widely as a relatively inexpensive means to improve fuel economy and curb emissions. And 7-, 8- and even 9-speed transmissions will become more common as a means to further fuel efficiency.

There also is consensus future global vehicle platforms will be designed with plug-and-play capability to house virtually any type of powertrain in order to accommodate different market preferences.

But when it comes to the outlook for light-duty diesels in the U.S. and GM’s high-visibility Volt EREV, there is no sitting around the campfire singing “Kumbaya.”

Barb Samardzich, Ford vice president-global powertrain engineering, takes issue with Johannes-Joerg Rueger, senior vice president-engineering, diesel systems for Bosch, on the growth potential for light-duty diesels in the U.S.

She also chides GM’s highly touted Volt EREV for being too expensive for most consumers, suggesting Ford’s EcoBoost strategy of downsizing and turbocharging gasoline engines is a better way to offer improved fuel economy and lower emissions to the widest audience possible.

However, Larry Nitz, executive director-hybrid and electric powertrain engineering, GM Global Product Operations, says he drove a Volt up to Traverse City from Detroit and calls it “a beautiful thing.”

Rueger spends much of his presentation touting the benefits of diesels and arguing they are “under-represented” in the U.S. and that clean diesels can help auto makers meet tougher fuel-efficiency and carbon-dioxide-emissions regulations coming after 2016. He contends even though gasoline engines steadily are increasing in efficiency with downsizing, direct injection and new induction strategies, diesels are making parallel improvements and promise to stay well ahead of spark-ignition engines in efficiency for the foreseeable future.

Rueger also points to the growing take rate for optional diesels on an increasing number of European-brand vehicles being sold in the U.S. as a sign American consumers are beginning to accept the engine.

However, even though Samardzich spends most of her presentation touting the benefits of Ford’s new 6.7L Power Stroke heavy-duty diesel and its hefty increase in torque to 800 lb.-ft. (1,085 Nm), she is skeptical of the future for smaller light-duty diesels for passenger vehicles in the U.S.

She points to the volatility of U.S. diesel fuel prices and the prohibitively high cost of diesel-emissions technology that could pose hurdles for most consumers.

When Rueger argues the cost of diesel-emissions technology and components should come down through economies of scale as the engines proliferate globally, Samardzich abruptly ends the conversation. “I anxiously await your revised (price) quotes from Bosch,” she says.