February 12, 2018
Since the U.S. Environmental Protection Agency’s (EPA) engine tiers mandate came out in 1996, there have been varying degrees of implementation. Based on the phase-in of Tiers I through Tier 3 and ending with Tier 4 Interim (T4i) and Tier 4 Final (T4F), there have been different emissions levels acceptable for larger and smaller pieces of equipment that have changed throughout the phase-in.
“Sometimes it has been hard for people to grasp what tier equipment they are dealing with and the complexity of the machine,” says Brad Stemper, product manager for Case Construction Equipment. “They have tried to categorize where everything fits in — whether processes are happening in or after the engine.”
Tier 1 and Tier 2 emissions processes essentially all took place in the engine, Stemper points out. With Tier 3, Tier 4 interim, and Tier 4 Final came exhaust gas recirculation and after-treatment systems.
“The emissions mandates created complexity due to the OEM’s chosen path to compliance,” Stemper says. “Some manufacturers chose to implement one solution across all products, and others chose various solutions depending on what specific solutions made sense for different machines and applications.”
The key to effectively managing mixed equipment fleets is to take a comprehensive inventory and create a “cheat sheet” for each machine, Stemper says. “I suggest this to our own fleet managers,” he says. “You need to know what machine you are looking at and what it has as far as the emissions control system.”
There are myriad emission control technologies, including cooled exhaust gas recirculation (CEGR), diesel oxidation catalyst (DCO), diesel particulate filter (DPF), and Selective Catalytic Reduction (SCR).
“There are variations of these,” Stemper says, “so it’s important to familiarize yourself with your applicable equipment and technologies to be most proficient.”
For engines equipped with SCR technology, this includes understanding proper handling and transporting of diesel exhaust fluid (DEF) for Tier 4i and Tier 4F equipment, says Luke Van Wyk, national sales manager for Thunder Creek Equipment.
Using a closed system to transfer DEF from container to container eliminates potential contaminants, he notes. Many of the closed DEF systems come with the same kind of dispensing nozzle as found on fuel pumps. They are kept “closed” through the same type of coupler found on a keg tap, he adds, which eliminates contaminants that could occur with the use of a DEF poured from an open container into a funnel inserted into the DEF tank.
“SCR system failures are directly related to how DEF is handled and, most likely, someone in the supply chain who contaminated it on the way to the machine,” he says. “Equipment operators and managers shouldn’t be afraid of technology. It is unavoidable, but with proper education and practices, equipment will become a seamless part of any operation. The key is to be intentional with management to have the right systems in place so there is no negative experience with technology.”
Brad Stemper is a product manager for Case Construction Equipment (CE). His previous role was solutions marketing manager handling a variety of solutions, including emissions control technologies across the North American CE product line. He also worked with the sales channel and customers to identify ways to help their equipment and businesses operate more smoothly. He holds both a bachelor’s and master’s degree from the Milwaukee School of Engineering and has worked with Case since 1999 in a number of roles, including commercial training and as a technical specialist.
Luke Van Wyk is an owner and national sales manager for Thunder Creek Equipment, an Iowa-based manufacturer dedicated to bringing new and innovative solutions for handling fuels, fluids, and maintenance in the field. The company’s applications include a proprietary two-in-one diesel exhaust fluid (DEF) pumping system used to ensure DEF cleanliness, and purity, particularly in dirty off-road applications to keep selective catalytic reduction (SCR) systems and, thus, equipment working.
A little preparedness goes a long way when it comes to operating and maintaining equipment of mixed tiers with varying emissions technologies, says Brad Stemper, solutions marketing manager for Case Construction Equipment. “It can be overwhelming, depending on the fleet size,” he says, adding that fleet managers and equipment operators should take advantage of the knowledge base of equipment dealers and distributors. “Make them your No. 1 point of reference. They will have all the information for every group of equipment standards in the industry and be able to advise fleet managers of the most important points.”
Stemper likens it to driving a car. All vehicles have four wheels and a steering wheel, but each make and model has subtle differences, and there are varying features and technologies. Vehicle owners often do not read the manual before operating it. The same can sometimes be said of off-highway equipment. A seasoned wheel loader or excavator operator may not realize some of the minute — and not so minute — differences. “Being familiar is the No. 1 thing that needs to happen to be more productive and profitable,” Stemper says.
As new equipment technology is introduced, the fluids used — such as longer-maintenance coolants — are “completely different” than traditional coolants used just 10 or 15 years ago, Stemper points out. “You can’t just top off anti-freeze anymore,” he says. “You have to understand what your equipment uses and that the coolants can’t be mixed, because they will ‘gel up’ and eliminate the cooling capacities. You have to understand what you have so you know how to respond.”
Some equipment still requires the use of diesel particulate filters (DPFs). Small, lower-horsepower machines use a combination of an in-engine system and diesel oxidation, and don’t require additional monitoring. However, once equipment reaches higher thresholds — i.e. above 75 horsepower — simplistic emissions controls aren’t able to achieve the emissions requirements. That’s when Case implements a Selective Catalytic Reduction (SCR) system into most of its higher horsepower products. “These [SCR] systems require DEF to be added, but there aren’t any concerns of needing to pull the machine off to the side and burn extra fuel just to run regeneration,” Stemper says.
It is important for operators to understand that equipment using SCR technology needs to maintain the proper amount of DEF — a precise mixture of high-purity urea and de-ionized water. This chemical mixture is injected into the exhaust system to reduce NOx emissions in the exhaust.
“If you run low on DEF, the machine will literally ‘pull’ the engine down and affect productivity,” Stemper says. “It’s important to keep reiterating that you have to fill up DEF. Watch the DEF gauge in each machine and have a reference card in the cab or operator station about what to check or do if a specific warning occurs.”
The most important advice for managing the diesel exhaust fluid (DEF) used in Tier 4 Interim and Tier 4 Final equipment is maintaining its purity through proper handling, advises Luke Van Wyk, owner and national sales manager for Thunder Creek Equipment.
“You need to be very intentional how you handle DEF,” he explains. “There are well-defined risks if it’s not handled properly.”
Although DEF isn’t hazardous, proper management and handling practices are necessary to prevent contamination that can have serious effects on machine health and performance.
Not only will Tier 4 machines “literally shut down” if they are DEF deficient, but it requires a technician to assess the machine and interface with the ECM. “You can’t just put more in and start up the equipment again,” he points out.
The source of DEF also matters, because this reflects its quality. The American Petroleum Institute (API) certifies DEF manufacturers for meeting ISO standards, Van Wyk notes. A black, square label with API indicated on it signifies that the DEF is coming from a reputable source.
“It gives them assurance, especially because there are so many ‘backyard blenders,’” he says. “Urea is being blended with water and then being passed off as DEF. This could create some significant issues for the equipment due to contamination.”
The catalyst found in Selective Catalytic Reduction (SCR) systems is made of rare metals such as tungsten, vanadium, and zeolite. When DEF is injected into the exhaust stream, it converts to ammonia. The ammonia and exhaust enter the catalyst and produce a chemical reaction with nitrogen oxide (NOx), converting it to water and nitrogen, which is completely inert, before releasing it through the equipment’s exhaust pipe.
“Chemicals such as ammonia and urea are very corrosive,” Van Wyk explains. “If any metal contaminants get into the DEF, they will get trapped inside the catalyst and cause problems. As the DEF keeps coming in and the ammonia keeps entering the catalyst, those trapped minerals and the resulting corrosion will essentially cause the catalyst to rust from the inside out.”
Van Wyk likens DEF contamination to an infection in the human body. “If I go in for knee surgery tomorrow, and that scalpel isn’t clean and sterile, I may get an infection,” he says. “That infection will grow and grow over time until it makes me ill. Mishandling or contaminating DEF — like an infection in the body — will spread throughout the system and cause serious damage.”
Once this occurs, the catalyst cannot be repaired — only replaced — and this can cost thousands of dollars.