Equipment World Digital Magazine
Issue link: http://read.dmtmag.com/i/846046
July 2017 | EquipmentWorld.com 38 ing enough space to accommodate the Tier 4 replacement engine," says Mike Rochford, director of emis- sions regulations and conformance at Caterpillar. "When considering a repower to Tier 4 in an older machine, there must be room to fit the SCR aftertreatment, a DEF tank, controls and a cooling system that can be up to 30 percent larger than the previous engine. While some machines have the space to fit this Tier 4-related equipment, often the engine compartment does not have the extra room." Another complication with the new engines is the sophisticated electronic controls and sensors that help them and the machines they power be more efficient, says Oftedal. Higher tier machines all use an electronic control module (ECM) that acts as the machine's brain. The ECM gets information from sensors in the transmission, details about engine speeds, tem- peratures and loads, data about the exhaust aftertreatment and how well it's performing. Algorithms in the ECM then decide on power levels, injection timing, shift points and a wide range of performance options to maximize the machine's productivity and fuel efficiency. To put one of these engines in an older tier machine may require an almost impossible amount of reen- gineering and additional upgraded componentry to communicate with the ECM. "It's a whole new world of soft- ware integration that is not back- wards compatible," says Oftedal. In these cases, you're going to be bet- ter off just buying a new machine. You can sometimes successfully repower from a Tier 3 or earlier engine to a Tier 4 Interim or Tier 4 Final engine with applications in which the engine is static and not bolted into a mobile piece of equipment, says Carl Micu, man- ager of OEM engine sales Americas and drivetrain sales worldwide, John Deere Power Systems. Ex- amples include large trash pumps, light towers and gen sets. In these applications, the engine is often mounted on a skid or platform, and you don't have the space constraints that occur with mount- ing an engine in a piece of mobile equipment. And since the engines in these applications generally run at a steady rpm and don't have to rev up or down in response to loads, they don't need sophisticat- ed software running the ECM. Getting it done Assuming you can meet all your emissions requirements, it's best to consult the engine OEM and discuss the cost and feasibility before you decide to buy used equipment that needs a new engine or to repower something in your own fleet. "Is it in suitable condition to justify the investment?" asks Roch- ford. "Items such as the machine frame condition, age and intended working conditions factor into the assessment. The condition of the hydraulics and drivetrain is the next biggest driver as to whether a machine would make a good can- didate." Owners must also analyze the cost relative to other options, including the price of a new ma- chine, used machine or rental/lease options, Rochfort says. And note that your engine pro- vider will likely need to assess the machine you're putting it in unless it's a swap for an identical engine model. "You have to do an applica- tion and appraisal," says Schultz. "Make sure the cooling system will cool, the charge air system will maintenance | continued Engines used in stationary equipment are typically easier to repower with Tier 4 Interim and Tier 4 Final engines.