TAKING ON THE NEXT TIER 4 THRESHOLD Cummins unveils engines to meet 75 to 173 hp emissions standards for 2012; Cummins Compact Catalyst key addition
BY MIKE BREZONICK Jan. 1, 2011, is the date many in the engine-powered equip- ment industry have memorized as the start date for the EPA’s Tier 4 engine emissions standards. Yet it’s just one of the Tier 4 milestones still ahead, as it affects only the engines in the 174 to 750 hp power band. Exactly one year later, Tier 4 begins for engines between 75 to 173 hp, and while to date most of the industry’s at- tention has been on the how and how much of the 2011 technology, the 2012 standards, which have their own unique challenges, suddenly seem a lot closer. Thus it was that Cummins, which was among the first engine manufac- turers to establish and publicly explain its 2011 Tier 4 technology path, used the recent Bauma exhibition to reveal the engines and technologies it will use to surmount the 2012 hurdle. Cummins displayed the latest gener- ations of its four-cylinder QSB3.3 and QSB4.5 engines, which the company said are designed to provide a simpli- fied Tier 4 installation across a 75 to 160 hp power range. The QSB3.3 cov- ers an output range of 75 to 110 hp, while the QSB4.5 spans a range of 110 to 160 hp. Peak torque ratings remain unchanged from Tier 3, with the QSB3.3 topping out at 306 lb.ft. and the QSB4.5 reaching 466 lb.ft. Much of the Tier 4 technology being applied to the 3. 3 and 4. 5 L platforms is familiar, as much of it was what Cummins used on many of its larger engines for 2011. These include: • the Direct Flow air cleaner from Cummins Filtration, which is engi- neered to provide more perform- ance and dust-holding capacity in a more compact envelope; • an electronically controlled, high pressure common rail (HPCR) fuel system; • the CM2250 electronic control module (ECM), the company’s common Tier 4 control platform;
• a scaled-down cooled exhaust gas recirculation (EGR) system for NOx reduction; and • a variable flow turbocharger that incorporates a simple variable tur- bine mechanism designed to im- prove boost across a wide engine speed range. While nearly all of that had been seen in one form or another before, the new engines included one small additional item that drew big interest at Bauma, the Cummins Compact Catalyst developed by Cummins Emission Solutions. Shown publicly for the first time in Munich, Germany, the Cummins Com- pact Catalyst incorporates a catalytic coating and substrate within a stain- less-steel can, all tailored specifically to the QSB3.3 and QSB4.5 engines. It is designed to remove particulate mat- ter (PM) from the exhaust stream by simple, flow-through passive oxidation and was engineered to be extremely compact to allow for tight installations on smaller equipment. “It’s the next evolution of the diesel oxidation catalyst (DOC) for Cummins,” said Chris Calas, engine manager for the QSB3.3 at Cummins. “It involved fine tuning the substrate surface and the washcoat to get the highest PM reduction while using the least amount of precious metals in order to make it as cost-effective as possible.
Cummins used the recent Bauma show to unveil its engines and technologies for the 75 to 173 hp Tier 4 interim/Stage 3b standards that take effect in 2012. The Tier 4 engines include the four-cylinder QSB3.3 (left) and four-cylinder QSB4.5 (right), and one of the key technolo- gies is the new Cummins Compact Catalyst (center).