PSA Peugeot-Citroen could delay the introduction of plug-in diesel-electric hybrid cars, including the stunning Prologue (pictured below), as it seeks to cut costs during the economic downturn.

Ladimir Prince, manager of PSA’s hybrid innovations unit, said though the carmaker’s plug-in hybrid project could be delayed by a year or two, the economic crisis will not slow the firm’s plans to launch diesel-electric hybrid models.

Prince said PSA is still working toward launching a diesel-hybrid powertrain in 2011 in the Peugeot 3008 crossover though admits sales are now projected to be in the tens of thousands, not nearly as high as earlier estimates had forecast.

Prince gave an overview of the manufacturer’s hybrid vehicle plans in Rouen in northern France during a trade show, where he remarked PSA is moving forward with research on plug-in electric hybrids, but does not have a date for series production.

“A lot of our future decisions will depend on battery costs,” Prince said. “More government support for alternative propulsion vehicles could also speed development”.