DETROIT - With higher government fuel economy requirements looming and gas costing about $3 per gallon, Chrysler Group announced new measures to boost mileage for its cars and trucks.

The company announced that its new family of V-6 engines would have the ability to drop to three cylinders when less power is needed, raising the fuel economy by 6 to 8 percent.

The announcement included that "within the next few years, Chrysler will offer a mild-hybrid powertrain in a Chrysler Group vehicle." The company also said its two-mode hybrid program will expand beyond the Chrysler Aspen Hybrid and Dodge Durango Hybrid, both of which debut next year. The automaker indicated that 2009 will be a critical model year, with the rollout of a Jeep Grand Cherokee Bluetec with a clean-diesel engine and the debut of a "significantly upgraded version of the 5.7L Hemi V-8, resulting in notable gains in fuel efficiency."

The new Phoenix family of V-6 engines will get a multi-displacement system. The engine will operate on three cylinders when less power is needed and in V-6 mode when more power is required. The automaker said the system will result in a fuel economy gain of 6-8 percent. A new 4.7L V-8 will get a 5 percent fuel economy improvement with up to 75 more horses and 35 more pound-feet of torque.

Chrysler Group said it will take the new common-axle technology now featured in the Chrysler 300C SRT-8 and move it to other Chrysler Group vehicles, for gains in fuel economy.

Frank Klegon, executive vice president for product development, said the company is making the investments in anticipation of stronger government fuel economy requirements.

"We have developed and are implementing a series of major initiatives — including a bigger push in hybrid and clean-diesel technology — to meet the needs of American consumers," said Frank Klegon, Chrysler Group's executive vice president of product development. “We’re moving forward with real urgency to improve fuel efficiency across our entire lineup,” Klegon said.

The company will explore the possibility of a four-cylinder diesel engine for North America. It also plans to add a new fuel-efficient dual-clutch transmission to its lineup with 2010 model vehicles.