Taking the No-SCR Approach

Deere explains move forward with interim Tier 4 engines that don't require diesel exhaust fluid.

Published on: Aug 26, 2010

In advance of the fall farm show season, farmers might want a primer on what to expect for engine power choices from the major manufacturers. For Deere, the choice for the next three years is pretty clear: You won't see much of a change.

That choice, which is part of a strategy aimed at providing what the company says is a "key advantage" in the market, differs from the other three players in the business for 2011. "We're more confident than ever that these are the right solutions to meet emission standards," says Goeff Stigler, product marketing manager, John Deere Power Systems.

Major engine makers face a two-step process for meeting much tougher emission standards - called Tier 4. There's an interim step that takes effect in 2011 for engines with 175 horsepower and above; then just three years later (a short amount of time for engineers and designers) Final Tier 4 takes affect. The chart below shows how dramatic the emissions changes since 1999.


From Tier 1 in 1999 to January 2011 engine makers have had to make significant cuts in NOx and particulate emissions. Bright yellow in front shows the largest engines and their progress.

During a conference call earlier this summer, Stigler outlined the two approaches engine makers face for meeting emissions. "You can use a diesel particulate filter with a diesel oxidizing catalyst and cooled exhaust gas recirculation or go with selective catalytic reduction using urea," he says.

With SCR, engine makers might have fewer actual changes in the engine itself - although different manufacturers are taking different approaches. Deere has chosen the DPF/DOC approach - which means an added particulate filter to their current engine design.

In addition, Deere will use more exhaust gas recirculation which Stigler explains has worked well in the Tier 3 engines the company now sells. "We chose cooled EGR more than four years ago and that's supported by customer research," Stigler says. In fact, for the interim Tier 4 engines Deere will be launching at the Farm Progress Show and Husker Harvest Days in the next few weeks, EGR use will rise to as much as 30% to lower NOx.

How will you know? The new interim Tier 4 PowerTech engine launching next week is the PVX 9.0L. The P stands for Plus, the V for variable geometry turbocharger, the X for exhaust filter and of course 9.0L is the displacement. Deere has been using a variable geometry turbo in its Tier 3 engines, which allows precise control of airflow as the engine operates.

"With this approach we'll have three more years with a single-fluid solution with no reduction in reliability and fuel economy," Stigler says. "There are 160 Deere applications that use these engines and hundreds of outside applications too." EPA certified the 9-liter engine at the end of March 2010. Stigler says the engines have had 240,000 test hours and 42,000 vehicle test hours.

If you're headed to any of the big shows this fall, check out the engine choices being offered by the major producers. Deere's single-fluid approach is based on customer research and while the company is hard at work designing final Tier 4 engines for launch in 2014, it's keeping its options open.

As for pricing? The company announced a 5.7% increase for the 8R tractor with interim Tier 4 engine technology.