Work will begin immediately on a $69 million upgrade at General Motors Corp.’s DMAX Ltd. joint venture plant in Moraine, OH, as the operation is converted to production of a new 6.6L turbocharged diesel engine designed to meet strict new emissions regulations in 2010.

The investment tally includes renovations to the plant and new machinery and tooling and will retain more than 1,000 jobs at the 10-year-old facility, the auto maker says. The plant presently employs 1,195 people and builds 200,000 diesel engines annually.

John Buttermore, vice president-global manufacturing, GM Powertrain, says the investment reflects a commitment from GM to reduce fuel consumption and emissions across its global portfolio.

“This new investment demonstrates GM’s commitment to continue to invest in technologies that reduce the impact of our vehicles on the environment, while maintaining performance attributes required by customers in the areas of towing and hauling loads,” he says in a statement.

GM has released few details on the new 6.6L Duramax, but perhaps its greatest modification will be the addition of a selective catalytic-reduction after-treatment system to curb oxides of nitrogen emissions. Combined with a diesel particulate filter, the engine will meet the Tier 2 Bin 5 and LEV 2 emissions standards coming in 2010. GM says the engine will be compliant in all 50 states.

The current 6.6L mill, a 4-valve, high-pressure, common-rail direct-injection diesel with a particulate filter but no after-treatment system, has helped drive up substantially GM’s share of the heavy-duty truck market since its introduction in the ’01 model year. GM says its market penetration rose to 33% last year, up from 3% in 2001.

GM offers the engine in Chevrolet Silverado/GMC Sierra heavy-duty pickups, as well as Chevy Kodiak/GMC TopKick medium-duty commercial vehicles and Chevrolet Express/GMC Savana fullsize vans.

Buttermore joined other GM powertrain executives, state and local officials, and leadership from the plant’s IUE-CWA Local 797 to announce the investment today in Moraine.

GM and Isuzu Motors Ltd. launched the DMAX JV in 1998. GM owns 60% and Isuzu controls the remainder. GM recently divested its stake in Isuzu, which it leveraged primarily for diesel-engine development, and Toyota Motor Corp. snatched up 5.9% of the Tokyo-based manufacturer also as a diesel technology play.

DMAX rolled out its 1 millionth Duramax V-8 turbodiesel in May.