DETROIT – A fuel-efficient, direct injected Ecotec 2.4L four-cylinder engine will be the third engine offered in the 2010 Buick LaCrosse luxury sedan, General Motors announced. 

Backed by a fuel-saving six-speed automatic transmission, the new powertrain combination is expected to deliver fuel economy of 30 mpg highway and 20 mpg city, making LaCrosse one of the most fuel-efficient cars in its segment. 

The Ecotec 2.4L four-cylinder joins the lineup later this year as the standard engine in the LaCrosse CX. Direct injection technology helps it deliver 182 horsepower (136 kW) and 172 lb-ft. of torque (233 Nm). Buick expects about 25 percent of customers will opt for 2.4L-equipped models. 

The 2.4L's injection of fuel directly into the combustion chamber enables a higher compression ratio to increase efficiency and horsepower. That means more power is made with less fuel and lower emissions. In fact, cold-start emissions are reduced by up to 25 percent with direct injection, GM said. Engineers tuned the Ecotec 2.4L engine to deliver greater torque at lower rpm and build it smoothly toward its peak at 4,900 rpm. 

"Direct injection is a key component of GM's ongoing strategy to use advanced propulsion technology to help us deliver more fuel-efficient cars today and in the future," said Tom Stephens, vice chairman of global product development. "GM is using multiple technology pathways to achieve increased efficiency and to diversify energy sources -- and we're applying them where they make the most sense for customers when it comes to efficiency, performance and cost." 

Every engine in the LaCrosse lineup is direct injected and matched with a fuel-saving six-speed automatic transmission. Along with the Ecotec 2.4L, a new, direct injected 3.0L V-6 is offered and a larger-displacement, more powerful 3.6L V-6 is standard on the LaCrosse CXS model, GM said.