New EPA Regulations Will Require Machine Reconfiguring, Add Cost

Final Tier 4: Size & Expense
By Jeff Griffin, Senior Editor | June 2010 Vol. 65 No. 6
The engine compartment of the Ditch Witch HT300. Final Tier 4 engines will likely be larger, requiring redesign.

“In developing our SCR technology solutions we benefited from Fiat Powertrain Technologies’ consolidated experience from on-road Tier 2 and Tier 3 applications developed for engines in more than 100,000 trucks and commercial vehicles sold since 2006. This extremely valuable resource, coupled with the tremendous construction equipment design expertise of our global R&D teams, has enabled us to develop SCR solutions specifically optimized for the load cycles of off-road equipment.”

Charles Machine Works, David Campbell, priority project manager: “Equipment owners need to know that equipment will be more expensive -- my estimate is a 5 percent MSRP increase for equipment larger than 174 horsepower. For equipment between 75 and 174 horsepower, the increase may be larger. They will be expensive to operate. An additional consumable fluid will likely be needed. Also, additional steps may be needed to prepare for long-term equipment storage.

“Equipment manufacturers will need to modify equipment to accommodate Final Tier 4 engines. The SCR module is expected to be somewhat larger than a conventional muffler. These modules will be similar in size to the DPFs that will be added starting in 2011. An additional tank for diesel exhaust fluid (DEF), which SCR requires, will be needed. DEF consumption is expected to be 2 to 5 percent of fuel consumption. As a bare minimum, the DEF tank should be 5 percent as large as the fuel tank. Depending on the OEM’s chosen DEF refill strategy, the tank could be much larger. Electronic components to monitor and control the SCR performance plus a pump to control the DEF usage rate will be integral parts of the system. Finally, the DEF tank will need heating components to thaw the fluid when temperatures are below 15 degrees Fahrenheit.

“The SCR systems that are expected in 2014 should be very similar to those introduced on model year 2010 trucks. There will likely be some differences between on-road and off-road applications, but I expect those to be subtle.

“I am not aware of any particular routine maintenance issues with SCR. There is at least one intermittent issue related to machine storage. DEF is a 32.5 percent aqueous urea solution, meaning it is 67.5 percent water and 32.5 percent urea. When a machine is unused for an extended period, the water can evaporate, leaving a solution that has a higher than desired concentration of urea. In the worst case, all the water evaporates leaving urea crystals in the tank. The DEF tank should probably be drained if a user expects to park a machine for an extended period.”