This summer, Chrysler has begun a three-year powertrain overhaul.

First to debut: Chrysler's gasoline-electric Two Mode hybrid. Next comes a family of high-tech V-6s.

And in 2010, two powerful Cummins diesel engines will debut in the Dodge Ram and Jeep Grand Cherokee.

Here's a snapshot of Chrysler's powertrain plans.

Hybrids

The 2009 Dodge Durango and Chrysler Aspen SUVs, which go on sale in August, will be offered with a Two Mode hybrid system that incorporates a 385-horsepower, 5.7-liter Hemi V-8 with a cylinder cutoff system.

The engine is combined with the Two Mode four-speed automatic hybrid system, developed by General Motors.

The system will be shared with BMW and Mercedes-Benz. The Two Mode powertrain propels the vehicle on electric power at speeds up to about 25 mph. Chrysler estimates fuel economy at about 20 miles per gallon city. Overall fuel economy is expected to increase 25 percent.

But the combination of Chrysler's efforts to reduce its model line and shrinking SUV sales may result in the Durango and Aspen hybrids being offered for only one or two model years.

In 2010, Chrysler will offer the Two Mode powertrain in the light-duty version of the Ram pickup.

It is unclear which Chrysler vehicles will use the front-drive version of the Two Mode system. The Dodge Caliber and Jeep Compass and Patriot are good candidates for the Two Mode transmission, says Paul Lacy, manager of technical research at Global Insight, a forecasting firm in suburban Detroit.

Other candidates are models built off the automaker's upcoming global midsized vehicle platform.

Diesels

The diesel engine's future in North America may not be as bright as it was two years ago when Chrysler was making powertrain decisions.

At that time, diesel fuel, depending on region, was around 30 cents a gallon cheaper than regular unleaded gasoline. Now, diesel in some regions is nearly $1 a gallon higher.

The Grand Cherokee diesel is doing well enough to stay in the lineup. In 2010, Chrysler will switch diesels from the 3.0-liter Mercedes-Benz engine to a 4.2-liter Cummins V-6. The Cummins V-6 and a 4.7-liter V-8, also from Cummins, will be used in Dodge Ram pickups and possibly the full-sized truck Chrysler will build for Nissan.

As for cars, Chrysler is studying whether to offer Chrysler 300 customers the diesel it sells in Europe, a 3.0-liter V-6 from Mercedes-Benz.

Chrysler spokesman Nick Cappa said every vehicle Chrysler sells in Europe, except the Dodge Viper, is available with a diesel engine.

Diesel availability may be expanded to other models in the United States, he said.

"There has to be enough consumer interest and customer awareness to make a profitable business case," Cappa said.

For the 2010 model year, the Jeep Wrangler could get a turbocharged, four-cylinder diesel, sources say.

The four-cylinder diesel offered in Europe is made by Italian engine manufacturer VM Motori S.p.A. but does not meet emission standards in all 50 states.

Gasoline engines

In 2010, Chrysler rolls out its family of overhead-cam V-6 engines, called Phoenix. The engines will be available in four displacements and have such fuel economy features as direct injection, variable valve timing, turbocharging and a cylinder cutoff system.

Chrysler also is expected to adopt smaller-displacement, turbocharged four-cylinder and V-6 engines, said Eric Fedewa, an analyst with CSM Worldwide in suburban Detroit. Chrysler's four-cylinder engines will add direct injection to boost fuel economy.

Electric vehicles

In September 2007, Chrysler formed ENVI, an engineering organization that has as its mission the creation of electric vehicles for Chrysler, Dodge and Jeep.

Recently, Cappa said ENVI is "aggressively committed to bring electric vehicles to Chrysler, Dodge and Jeep as soon as possible."

At the 2008 Detroit auto show, the automaker unveiled three alternative-powertrain vehicles:

1. Dodge Zeo, a four-seat sports car with a 258-hp electric motor.

2. Jeep Renegade, a sporty off-road vehicle with an electric motor on each wheel and a small diesel engine.

3. Chrysler ecoVoyager, a people mover with an electric motor and a hydrogen fuel cell as a range extender.

But Chrysler has no plans to build any of the three.

Transmissions

To boost fuel economy, Chrysler will add six-speed automatic and dual-clutch transmissions.

The dual-clutch transmission, built with Getrag Corp., is expected to deliver about a 6 percent fuel economy gain over Chrysler's four-speed automatic, which will be dropped. The transmission arrives in 2010.