DEARBORN, MICH. (Sept. 27, 5:30 p.m. ET) — Ford Motor Co. has found that efficiency comes at a price. Noise.

When engineers for the Dearborn-based automaker tuned the engine for Ford’s new 2013 Fusion hybrid sedan to get the most miles out of each gallon, the engine produced what the carmaker termed “unpleasant powertrain sounds.”

So to keep the efficiency without annoying drivers and their passengers, Ford is equipping the Fusion with “active noise-cancellation technology,” complete with speakers integrated into the headliner and flooring and a control box that can generate a reverse sound signal inside the car to mask the sound, it said in a Sept. 26 press release.

Automakers and their suppliers have been looking at a variety of noise issues related to future cars for years. The industry has faced issues with requirements in Europe to reduce engine noise outside cars so they are less annoying to pedestrians. But it also faces concerns globally that electric cars and hybrids must produce some kind of sound as a warning to alert people who are visually impaired that a car is nearby.

There have been active noise-cancellation systems in air-intake manifolds, extra sound absorption layered between the passenger compartment and engine to block sounds and additional film layers in auto glass to cut out road noise.

Ford’s system is designed to keep drivers comfortable while they also achieve 47 mpg performance.

The Fusion hybrid places three microphones within its headliner, with two microphones over the first row of seats and one over the rear seats. Those microphones measure engine noise and send a signal to the electronic active noise-cancellation control module mounted behind the instrument panel.

The module will generate opposing sound waves to cancel out the objectionable sound, and direct that sound through the audio system.

The hybrid will make it into dealer showrooms in North America later this fall.