It may sound like the title of a modern-art exhibition, but Volvo’s new i-ART system slated for the automaker's 2014 2.0-L four-cylinder diesel engines might instead represent a higher state-of-art in emissions reduction.
Powertrain Engineering Vice President Derek Crabb said the i-ART system, to be publicly revealed Sept. 10 at the 2013 Frankfurt Motor Show (IAA), is a breakthrough of similar significance to the arrival of the lambda oxygen sensor in catalytic converters, pioneered by Volvo almost 40 years ago.
The initials stand for Intelligent Accuracy Refinement Technology. Developed by Denso and first shown at the 2011 IAA, the technology features a fuel-pressure sensor and a microcomputer, which monitors injection pressure based on various input data, integrated into the top of each fuel injector. The closed-loop system precisely manages injections of fuel to match specific drive cycle conditions. It replaces the single pressure sensor typically positioned in the fuel rail.
The new Volvo diesel’s common-rail system operates at a very high 2500 bar (36,259 psi). It was developed to complement the i-ART and bi-turbo boosting to deliver required improvements in emissions and performance. The system will first be used on the diesel-powered 2014 S60, V60, and XC60 FWD cars.
Fuel consumption of the new engines is reduced by 10-30% compared to units of similar output but of larger capacity, Crabb claimed. Denso engineers have stated that i-ART can improve fuel efficiency by 2%, compared with open-loop systems. It was developed to enable diesel engines to meet Euro6 regulations with a reduced aftertreatment burden. Toyota also is using i-ART systems in upcoming 3.0-L commercial diesel engines.
A secondary but significant aspect of Volvo's new diesels with rated outputs up to 168-kW (225 hp) and 400 N·m (295 lb·ft) is their sound, which Volvo has engineered to appeal to their targeted end-users’ expectations.
The 2014 diesels are part of a new family of power units called E-DRIVE, which emerged from a development program known as Volvo Engine Architecture. They cover both gasoline and diesel technology and replace eight current engines. They will drive through an eight-speed automatic transmission or six-speed manual, with ratios optimized for economy.
The engines were developed with the intent to integrate them with Volvo’s hybrid-electric programs to give power figures “in V8 territory,” said Crabb. The associated electric motors could be paired with the IC engine at the front of a car or at the rear (to provide front or all-wheel drive), with the battery centrally positioned in both cases. Volvo is also testing flywheel solutions for its hybrid program (go to http://www.sae.org/mags/aei/12096).
The gasoline engines are rated at up to 225 kW (302 hp), the most powerful using a combination of supercharger and turbocharger to improve low-end torque and help achieve a linear power delivery. Variable valve timing technology is incorporated. Volvo has also focused on minimizing friction, with the camshafts running in ball bearings.
The diesels have an intelligent heat management system incorporating “smart valves” to help speed warm-up in low-temperature ambient conditions.
The test program for the new engine family included race experience in Volvo’s WTCC (World Touring Car Championship) entry in 2011.
The E-DRIVE power units were designed and developed at Volvo’s Gothenburg Powertrain Center and are built at its Skövde engine facility, which produced 412,343 units in 2012.