Aggregates Manager Digital Magazine
Issue link: http://read.dmtmag.com/i/932759
28 AGGREGATES MANAGER / February 2018 A little preparedness goes a long way when it comes to operating and maintaining equipment of mixed tiers with varying emis- sions 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 knowl- edge 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 some- times 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 capaci- ties. 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 pre- cise 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." T he most important advice for managing the diesel exhaust fluid (DEF) used in Tier 4 Interim and Tier 4 Final equipment is main- taining its purity through proper handling, advises Luke Van Wyk, owner and national sales manager for Thunder Creek Equip- ment. "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 seri- ous 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 equip- ment'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 contaminat- ing 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. Voices of Experience Brad Stemper Luke Van Wyk