The Environmental Protection Agency has dictated standards that now allow a tiny fraction of NOx compared with just 15 years ago.
After more than 15 years of work, the end is in sight. A steady stream of emission standards from the Environmental Protection Agency has prompted AGCO, Cummins, Fiat Powertrain Technologies, John Deere and other makers of off-road diesel engines to develop cleaner technologies. Today, manufacturers are preparing for Tier 4 Final compliance.
The Tier 4 Interim standard required a 90% reduction in particulate matter and a 50% reduction in nitrogen oxides. The final standard requires no further reduction in particulate matter but calls for an additional 80% reduction in nitrogen oxides (NOx).
These latest requirements are significant—particulate matter and nitrogen oxide levels must be reduced to near zero for most power categories by 2014. But original equipment manufacturers (OEMs) have stepped up to the challenge.
Selective catalytic reduction (SCR) and exhaust gas recirculation (EGR) are the primary means companies have used to meet Tier 4 Final standards. Some have blended the two technologies for a hybrid solution.
Case IH and New Holland, working alongside sister company Fiat Powertrain Technologies, have developed an SCR technology. SCR is an engine exhaust after-treatment that works outside the engine, unlike EGR or hybrid alternatives, and offers benefits beyond reduced emissions.
Fiat Powertrain Technologies 8.7-Liter Tier 4 Final Engine
"Case IH SCR-only systems help reduce the need for oil changes and cut fuel consumption compared to previous-generation emission systems," says David Stark, North American sales and product trainer for Case IH. "These types of changes can make a real, positive economic impact over time. Case IH SCR technology has provided high horsepower levels while using less fuel.
"When the emission components from the engine are removed, the engine can breathe and produce high levels of horsepower," he adds. "There are no emission components on the engines, which is one reason for the higher horsepower levels."
The right fit
John Deere has developed an Integrated Emissions Control system on engines of 75 hp and above that combines a diesel oxidation catalyst, diesel particulate filter and SCR, and which will be paired with its proven EGR system. John Piasecki, the company’s director of worldwide marketing, says this setup will deliver "power, performance, ease of operation, fluid efficiency, reliability and economical operating cost.
John Deere PowerTech PSS 9.0-Liter Tier 4 Final Engine
"At John Deere, we continue to offer the right combination of technologies at the right time to meet increasingly stringent emission regulations and customer needs," he says.
The Integrated Emissions Control system’s exhaust filter reduces particulate matter, while cooled EGR along with the optimized SCR reduce NOx to within Tier 4 Final regulatory levels.
Additionally, diesel exhaust fluid (DEF) consumption will be 1% to 3% of diesel fuel consumption, depending on the application. Piasecki says this allows the DEF tank size to be smaller, which in turn minimizes the impact on vehicle applications, extending DEF filter service intervals and limiting operator involvement.
John Deere touts its integration capabilities because it acts as the designer, manufacturer and servicer of its engines, drivetrains, exhaust filter, engine control units, cooling and other vehicle systems. This allows customers to get service at one of the company’s more than 4,000 service locations.
At AGCO, engineers continue to build on the company’s e3 SCR technology in its AGCO Power engines to address Tier 4 Final requirements. CEO Martin Richenhagen says that while emission technologies have changed throughout the years, the company’s overall focus has not.
AGCO Power Tier 4 Interim Engine
"Our e3 solution delivers exactly what modern agriculture demands," he says. "Cleaner emissions, improved economics and reliable performance."
In select models, a small amount of cooled EGR will be added to ensure emission compliance, minimize fluid consumption and improve the overall power balance.
"AGCO knows this technology well," says Matt Rushing, director of product management. "We were the first to launch SCR technology in the off-road market in North America and have many years of working experience with both emission reduction technologies. We wanted to develop a solution that would bring farmer input costs down, allow us to increase power levels and lower fluid consumption— all while offering reliable emission reduction technology."
Rushing adds that customers should not expect any changes to the way they operate and maintain their AGCO equipment. The company’s new engines will deliver total fluid economy (diesel fuel and DEF) that meets or exceeds the fluid consumption levels in its Tier 4 Interim machines, he says.
Cummins, meanwhile, has focused on developing products that deliver Tier 4 Final compliance with greater horsepower and improved fluid consumption, says Nishant Prabhu, general manager.
Cummins QSL9 Tier 4 Final Integrated System
"For example, the new rating for the QSX15 takes the Tier 4 Final engine 75 hp above the Tier 4 Interim top rating of 600 hp," Prabhu says. "This offers a new level of power capability for premium performance machines such as higher-horsepower tractors, combines and forage harvesters."
For products in the 120 hp to 400 hp range, Cummins is using an ultraclean after-treatment system by combining the Cummins Compact Catalyst with SCR technology. Heavy-duty products in the 350 hp to 675 hp range will meet Tier 4 Final regulations by combining the Cummins Particulate Filter with SCR technology. The QSK engine, with power from 750 hp to 800 hp, reaches Tier 4 Final compliance with a combination of clean in-cylinder combustion and an integrated SCR after treatment.
Prabhu says this approach has allowed Cummins to maintain a unique position in the market.
"Our strategy is designed to deliver optimal engine performance using a combination of best available combustion and after-treatment technology options. Our strategy has enabled us to fully optimize fuel efficiency, power, engine response and total operational benefits. All of our Tier 4 Final products will deliver industry-leading fluid efficiency while maintaining our superior performance characteristics like torque rise, power bulge and lowest operational costs," he says.
Because the Tier 4 Final architecture builds on the company’s Tier 4 Interim solutions, Prabhu adds, OEMs will face minimal installation changes.
Engines ready for the future
The improvements from these engine manufacturers have been incremental, but the net advances during the past 16 years are remarkable.
"In agriculture, success isn’t measured over one year," says Kyle Russell, senior director of marketing at Case IH. "Success is measured over the long haul."
- Machinery Guide 2013