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Turbos, Blowers and Real-World Fuel Economy

Turbos, Blowers and Real-World Fuel Economy

Just in case you hadn't noticed, auto makers around the world are jumping on the boosted engine bandwagon in a big way.

By replacing bigger engines with smaller ones, then boosting them to get the needed power, manufacturers are coming up with quick fuel-efficiency improvements. But they also are running into some real-world fuel-economy problems. More on this in a minute.

The market for turbochargers is growing so fast auto makers are encouraging more suppliers to get into the business. They don’t like it when a handful of companies dominate the global market for a critical technology.

Currently, the global turbo market for light-passenger vehicles largely is the domain of BorgWarner, Garrett (Honeywell) and IHI. But Continental and Bosch and Mahle have joined the fray. And yet there doesn’t seem to be any problems with too much capacity because demand is booming and will be for years to come.

Of course, turbochargers are not the only play in this game. Eaton’s superchargers are coming on strong, thanks to several innovations. Up until recently, superchargers mainly were on relatively large displacement V-6s and V-8s for high-performance cars. Not anymore.

Eaton now makes a tiny supercharger for the 1.2L Nissan Micra. It also has a supercharger on the hybrid version of the Nissan Pathfinder. And it will announce a diesel supercharger application for an unnamed OEM in the near future.

The knock against superchargers is that because they are belt-driven, they cause parasitic power losses on an engine. But Eaton is coming out with a clutched supercharger that only engages when needed, eliminating most of those losses. It’s also working on an electric supercharger that would need no belt at all.

So far, Eaton is the only player when it comes to mass-producing superchargers for passenger vehicles. But the OEMs will not tolerate that for long.

I’ve got to believe several purchasing departments are actively prodding other Tier 1 suppliers to start manufacturing superchargers.That would give them the leverage to hold the lid on prices just in case superchargers really strike the fancy of car buyers, thanks to the instant throttle response blowers provide.

A word of caution to those in the forced-induction world: In my experience, boosted engines smaller than 2.0L may deliver terrific fuel economy on dynos in the lab but are not so good in the real world.

Little engines simply must labor too hard to keep up with traffic, meaning you are in boost mode most of the time, and that kills fuel economy.

So far, consumers are enamored with the impressive mileage numbers they see on dealer showroom stickers, but prepare for a backlash if too many consumers are disappointed by what they actually achieve in everyday driving. Maybe some public education is in order, or maybe the OEMs need to keep real-world, not test-cycle calibration, at the forefront of their efforts.

If the public gets the idea auto makers are trying to pull a fast one, it could cripple one of the hottest technologies in the automotive industry.

John McElroy is editorial director of Blue Sky Productions and producer of “Autoline” for WTVS-Channel 56, Detroit, and “Autoline Daily,” the online video newscast.

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