A new diesel version of BMW's compact 3-Series will hit U.S. highways this year. BMW has offered a diesel engine in the 3-Series before with their 335d, but it was a 6-cylinder. The 328d offers a more efficient 2.0-liter turbocharged 4-cylinder that BMW says should deliver an estimated 45 mpg highway and in the mid-30's combined.

The new engine puts out 180 horsepower and 280 lb-ft of torque. It will have the same urea injection exhaust treatment as seen on other BMW diesels in order to meet U.S. emissions standards.

The 328d will be offered in both sedan and wagon body styles. Rear-wheel drive will be standard, with all-wheel drive offered as an option. The 328d wagon will be available only with all-wheel drive.

BMW's new 8-speed automatic will be the only transmission offered. It is more efficient than a manual and therefore the best fit for a car focused on maximizing fuel economy.

The 328d will have a "premium" over the 328i, which uses a turbocharged 4-cylinder gasoline engine. Production will begin in July 2013, and sales are set to kick off in July or August.

The new BMW 328d looks like a win-win, offering better fuel economy, likely twice the longevity, lower maintenance and higher resale value than the gas-powered 328i, without sacrificing performance. The base price will be below $40K USD.