The US auto industry remains unsold over the future of “green cars” such as electrics and hybrids, as carmakers struggle with the first steps in a market most agree shows promise over the long term. Automakers wheeled out a variety of new hybrids and plug-in electrics at the annual Detroit auto show this week, touting their great energy savings along with new, freshened designs. But despite that apparent commitment, behind the scenes, the manufacturers remain split between doubts and optimism [...]