Ford found that many drivers "shift by ear" rather than watching the tachometer. And with these downsized, slower-revving engines that are becoming the industry norm, the auditory clues about shift points get lost on the drivers. Ford claims that this cancels out the advantages of the down-sized turbo engines because they're not being driven within the envelope of greatest efficiency.
The solution is to train the driver to shift earlier by piping in a low-amplitude noise that occurs between cylinder firings, which increases the cylinder count to the driver's ear. Ford's patent allows the virtual cylinder count to be doubled or even tripled depending on how many artificial noises are superimposed between cylinder firings.
The company imagines this will be most beneficial on turbocharged 2- and 3-cylinder engines, and since manual transmissions aren't terribly common in American mass-market cars, this seems aimed at two groups: Europeans (who still buy small cars with manual transmissions in large numbers) and sports car buyers. Whether you like Ford's proposed system or not, at least it's less-invasive fuel-saving solution than cutting power or artificially limiting RPM.