ACtion Magazine - September/October 2012 - (Page 30)

Shutter up! A irflow shutters are back—did you even miss them? Have you ever seen them? The idea certainly isn’t new—they have appeared on the mid-1920s Cadillacs, an assortment of Packards in the the 1930s,Volvos from the 1950s and countless trucks and buses made through the 1980s as well as locomotives, ag equipment and aircraft. Now they are showing up (again) on an eclectic mix of modern vehicles. The earliest versions, usually slatted or similar to a window blind, used a cable or lever manually operated by the driver to block radiator airflow and aid a quick warm-up during cold weather. Over time, and as drivers became more forgetful or less adept, control was passed to a variety of vacuum or electromechanical devices which would open or close the flaps according to the coolant temperature. Eventually, better thermal management and more sophisticated engine management reduced the need, and by the late 1980s almost nobody, including the HD truck makers were using them. But everything old can be new again and the technology is re-emerging, notably on hybrid, eco and high-mileage variants of some 2012 and 2013 models and some highperformance cars as well. A quick survey shows some version of grille blockers (as they’re now called, or flaps or shutters) appearing on certain models of at least the Ford Focus, Lincoln MKS, Cadillac ATS, Chevrolet Cruze and Malibu, Buick LaCrosse, Dodge Dart, Ram 1500 trucks, Tesla Model S, Kia Optima, plus some Jeeps and Hyundai’s Sonata HEV. Additionally, the technology also appears on some Mercedes-Benz cars and a host of 5-, 6- and 7-Series BMW models in both Europe and North America. and engineers worldwide are literally under the regulatory gun to bring emissions down and fuel efficiency up. Most product managers would sell a body part to find an extra tenth of a mile per gallon or pull a few more grams of carbon dioxide out of the exhaust stream. Aerodynamic theory teaches that drag is a huge obstruction to the efficiency of an object moving through the air. Since the front ends of modern vehicles are no longer flat and square and every part in the airstream – mirrors, headlights, even wipers and wheelcovers – is massaged to offer the least resistance, plugging up some of the holes at the very front surfaces can produce a big change in air flow. Enter the front end air blocker, now usually found right behind the bumper air intake(s) rather than at the radiator or other coolers. When closed, they prevent some air from flowing through to the coolers and force that air around the car instead. Data from several manufacturers show that when these air control panels are closed – almost always at highway speeds – the improved aero reduces the need for engine power and can add roughly 0.3 - 0.5 mpg. That’s a huge gain from very little (and very old) technology. Additionally, using less fuel reduces tailpipe emissions, and some manufacturer’s tests have recorded as much as a two percent reduction in CO2 emissions. Röchling Group KG The shutter blades on the Chevrolet Cruze block only the lower air intake in the bumper. Röchling Engineering Plastics makes this multi-blade unit for BMW. So what happened, and why the renewed interest—did 100 years of cooling and control technology suddenly vanish? In a word, no. Heat management technology improves every year as do materials, fluids and control strategies. The reason is elsewhere, and until recently it had gone unnoticed from the days when it didn’t much matter. The secret is aerodynamics and its effect on fuel mileage. Designers 30 ACTION • September/October 2012 The most common industry term for the system seems to be “active grille shutters” (AGS), but you’ll also encounter AAF for Hyundai’s active air flap or BMW’s “air vent control” and “active aero” designations. The components are fairly straightforward, with most using one actuator to control the assembly. Some simply open or close a single panel or a set of louvers, while other types can control the amount of closure to a fine degree using bus, PWM or other digital protocols. In almost all cases, the shutters block only one or two air pathways, never the entire airflow. The coolers still receive moving air from under and over the bumper. This is one of those systems the owner won’t even know the car General Motors

Table of Contents for the Digital Edition of ACtion Magazine - September/October 2012

ACtion Magazine - September/October 2012
Table of Contents
Outlook
In Bin
Expansion Valve
Leonard’s Law
Under The Southern Cross
Cooling Corner
Virtual View
News & Updates
Got Diesel?
Shutter Up!
Association News
Quick Check
New Products & Services
Last Watch
2013 Training Event Program

ACtion Magazine - September/October 2012