Akerson, speaking on the sidelines of the AutomotiveNews World Congress during the Detroit auto show, said he has been pleased with consumer response to the newly launched Chevrolet Volt plug-in hybrid, so much so that GM now expects to sell more than 25, 000 Volts in 2011 and will add another Volt-like product, perhaps in the form of a small electric van, in 2012 or 2013.