GM is expected to unveil the new 2016 Cadillac CT6 next spring. The CT6 is expected to be a big, high-tech super-sedan that takes styling cues from last year's Elmiraj show car, shown above. Source: General Motors.

The new top-of-the-line Cadillac sedan will be called "CT6," according to General Motors. Why?

More details emerged this week on General Motors' (NYSE:GM) plan to revive its Cadillac luxury brand. Most of them make sense, but one is puzzling.

It was a bit of a surprise to learn that GM will make Cadillac a separate business unit, and that the brand's headquarters will move to New York City

It wasn't a big surprise, though. Both moves follow the pattern set by two other luxury-car brands: VW Group's Audi and Nissan's (NASDAQOTH:NSANY) Infiniti. New Cadillac President Johan de Nysschen is a veteran of both.

But a lot of experts were surprised and confused when GM announced on Wednesday that it would launch a new naming scheme for Cadillac's products, starting with its new super-sedan, which will be given the somewhat puzzling name "CT6."

Another new naming scheme for one of the industry's oldest brands
This is the first car to follow a new naming convention that will eventually spread across the Cadillac line.

As GM put it in its statement: "The name [CT6] also indicates a coming shift to a simplified naming convention for future Cadillac models. Under this strategy, familiar lettering like 'CT' would be used for car models, with the number indicating the relative size and position of the cars in the hierarchy of Cadillac models."

Will the next Cadillac ATS be called "CT3" or "CT4"? We'll have to wait to find out. Source: General Motors. 

A quick check of U.S. Patent and Trademark Office records shows that GM has already registered "Cadillac CT5," and presumably a range of others will follow. But they might not follow right away. Cadillac marketing chief Uwe Ellinghaus said in a statement that the renaming would be an "evolutionary process -- we will only change a product's name when the product itself is redesigned or an all-new model is created."

Cadillac's alphabet soup gets murkier
At first glance, it's a bizarre move, made even more bizarre by the contrast with Cadillac's long and rich history of evocative product names. Why not look to Cadillac's past and name the new super-sedan "Fleetwood," or "DeVille," or "Brougham"?

I think the answer is that GM, mindful of Cadillac's global aspirations and looking to the examples set by its luxury rivals, sees value in alphanumeric names that are the same in any language. (Of course, there's a counterargument to that: The two best-selling cars in the world eschew alphanumeric names for actual words, specifically "Corolla" and "Focus.")

Car enthusiasts, at least American ones, might have loved to see the new sedan called "Fleetwood," but Cadillac is clearly committed to the alphanumeric approach, at least for the time being. 

And now we know that over the next few years, Cadillac will abandon its current (moderately confusing) alphabet-soup naming convention for a completely different alphabet-soup convention that has the potential to be even more confusing. 

It seems weird, doesn't it? But consider this: It's exactly what Infiniti did a couple of years ago.

Infiniti just traded one bowl of alphabet soup for another, too
For years, Infiniti had designated its model ranges with a single letter: G for its sports sedans, M for its big luxury sedans, EX for its midsize crossover, and so on. The letters were followed by numbers that indicated engine size or trim level: G37, M45, etc.

As alphanumeric naming conventions go, it was fairly straightforward. Infiniti's customers didn't seem to have any trouble navigating it. 

But then, in a move widely hailed as an attempt to fix something that wasn't broken, Infiniti tore it all up. Starting in 2014, it said all Infiniti cars would be named with the letter "Q," followed by a number to indicate the specific model. The G sports coupe line became "Q60," the M sedans became "Q70," and so on.

Last year's Infiniti M35h became this year's Infiniti Q70 Hybrid. Confused yet? Buyers might be: Q70 sales are down 17% this year. Source: Infiniti.

Critics were not gentle. Autoblog called the move "questionable," Yahoo! Autos declared it "Q-razy," and The New York Times archly observed that "Infiniti did not hire one of the many brand consulting firms that rename products."

The executive behind that move? Infiniti's then-president, Johan de Nysschen. Apparently he thought it was a shining success, because it seems to be page one of his playbook for Cadillac.

This might not hurt much, but will it actually help?
Truth be told, Infiniti's renaming probably hasn't done much damage. In fact, it might not have mattered much at all: The new naming convention went into effect in January, and Infiniti's U.S. sales are up 7.2% this year. 

That OK, but not great. It beats the overall U.S. market's 5.1% increase, but lags most of Infiniti's luxury rivals: Toyota's Lexus (up 16.7%), Audi (up 14.5%), BMW (up 11.7%), and Mercedes-Benz (up 8.2%).

On the other hand, it beats Cadillac, which has seen U.S. sales fall 4% this year. 

Of course, what Cadillac really needs isn't new names. It needs more new products -- namely crossover SUVs, where Cadillac is losing sales to rivals on all sides -- and more time for picky luxury customers to catch on to the brand's much-improved products. 

Those new crossovers are coming, GM says, and de Nysschen promises that Cadillac will be given the time it needs to find its new audience. But apparently, the new products will be coming with a new set of names.

What do you think? Is GM shuffling the deck chairs on the Titanic? Or is there some real merit to this new naming convention? Scroll down to leave a comment and let me know.

John Rosevear owns shares of General Motors. The Motley Fool recommends BMW and General Motors. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.