Monday, February 11, 2013

Automakers defend turbo mileage, performance

Automakers defend turbo mileage, performance

Paul A. Eisenstein , The Detroit Bureau – 3 days

They’re billed as being the perfect automotive solution, able to deliver both improved fuel economy and solid performance, but do turbochargers live up to their billing? A review by Consumer Reports magazine has touched off a fierce debate.

According to a new report by Consumer Reports magazine, turbos are more hype than help, generally failing to deliver. In fact, the non-profit publication claims, turbocharged engines are often slower and less fuel-efficient than the conventional engines they replace.

Industry officials, however, are standing by the technology which, they contend, will help meet increasingly tough mileage mandates without sacrificing performance and ride quality like other high-efficiency alternatives.

A decade ago, turbochargers were found in limited numbers and generally used on sports cars and other high-performance products. Today, they’re increasingly commonplace on even the most mainstream models, everything from compact sedans to full-size pickups.

According to a study by Honeywell Transportation Systems – a major supplier of the technology – turbocharging is already in use on 25% of the new vehicles sold worldwide and could see an 80% growth by 2017.

“Turbocharged engines are expected to continue to grow globally because they meet the needs of consumers in a wide range of vehicle segments and geographic markets,” said Honeywell’s Vice President of Marketing and Product Management Peter Hill, citing “a combination of fuel-savings and performance at an affordable price” as a reason for their popularity.

But Consumer Reports is raising serious questions about such claims.

"While these engines may look better on paper with impressive EPA numbers, in reality they are often slower and less fuel efficient than larger four and six-cylinder engines," said Jake Fisher, CR’s director of automotive testing.

The magazine cited several examples, including the Ford Fusion with EcoBoost that it claimed delivered slower acceleration and lower mileage than many other midsize models – despite a $795 premium. Also flagged was the 1.4-liter turbo version of the compact Chevrolet Cruze which CR said was “barely faster” than comparable models.

Getting down to basics, turbos are a relatively simple technology, though the industry has come up with some sophisticated ways to maximize their performance. A turbocharger taps the energy in a vehicle’s exhaust to spin a fan that, in turn, forces extra air into the engine. Mixed with an additional charge of fuel, the powertrain can produce significantly more power than a conventional – or “naturally aspirated” – engine could with the same displacement.

Proponents claim that means a 2.0-liter turbocharged engine like the EcoBoost system in the Ford Fusion can deliver the power on demand of a conventional V-6. But when the vehicle is being driven more gently, say while cruising the highway where less power is needed, the turbocharger is idled and it yields the higher mileage of an inline-four.

“We cannot answer for how Consumer Reports tested the Fusion, but its findings are not consistent with our internal and external feedback. It shows EcoBoost vehicles lead in customer satisfaction for fuel economy across segments - including surveys by J.D. Power,” asserts Said Deep, Ford’s product technology spokesman.

Ford has heavily invested in its EcoBoost system, offering a variety of different versions on a wide range of models. It plans to offer the technology on 80% of the vehicles it sells in the U.S. by mid-decade, from the little Fiesta all the way up to the big F-Series truck. But Ford isn’t the only maker disputing Consumer Reports’ latest test results.

Hyundai, which uses turbocharging on a wide range of its own products, has also raised a flag. In fact, it believes CR has shown that its claims for real-world mileage, “in fact do correlate nicely” with official EPA fuel economy figures.

Consumer Reports isn’t the first to challenge the industry’s assessment of turbochargers. Ford has, in fact, come under sharp criticism from some quarters for the mileage of several new models – though such concerns aren’t limited to turbos.

Hyundai – and Korean sibling Kia -- recently had to restate fuel economy numbers on a wide variety of vehicles, though that was the result of testing anomalies.

General Motors officials, meanwhile, decided against offering a downsized, turbocharged engine in the all-new Chevrolet Corvette Stingray because testing showed it delivered not only higher performance but better mileage with a conventional, high-displacement engine.

But that underscores the increasing palette of technologies available to powertrain engineers, including such advanced systems as Direct Injection, displacement on demand – where some of an engine’s cylinder can be temporarily idled while cruising – and variable valve timing.

The debate over turbos is likely to continue but, at least for now, most manufacturers have plans to continue expanding their use of the technology.

Copyright 2013 The Detroit Bureau

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