This excerpt was originally posted on the John Deere, Straightforward Blog June 8, 2011. You can view the original post here.
With Interim Tier 4-equipped machines on their way to the field, we’ve found that regeneration of exhaust filters continues to be a source of questions for many operators. To help address those questions, we’re going to take another look at the basics of exhaust filter regeneration. Before we get started, be sure to check out our earlier video blog entitled Exhaust Filter Cleaning 101 for a little more background on the basics of John Deere’s exhaust filter regeneration strategies.
It’s important to understand that, in most cases, the regeneration process does not have an impact on machine operation or require operator involvement. Our exhaust filter regeneration strategies include:
John Deere engines and exhaust filter components are designed for uninterrupted operation using passive regeneration, a natural cleaning process where engine exhaust temperatures are sufficient to oxidize the particulate matter (PM) trapped in the exhaust filter. The process is continuous during normal engine operating conditions — greater than 30 percent load factor — and is the most fuel-efficient way to clean.
If conditions (temperature, load, or speed) for passive regeneration cannot be achieved, then PM must be removed using active regeneration, an automatic cleaning process. This requires injecting a small quantity of fuel into the exhaust stream for a short duration and elevating exhaust temperatures to clean the filter. It’s important to remember that, in most applications, active regeneration cleaning occurs only when passive regeneration isn’t possible based on temperature, load and speed. It serves as a backup system.
Active regeneration begins when the filter is partially restricted. The process will take approximately 25 to 50 minutes from start to finish. If normal operating conditions cannot be achieved and filter loading begins to occur, John Deere’s exhaust temperature management (ETM) system manages the initiation and duration of the active regeneration. The actual cleaning process takes approximately 20 to 30 minutes.
Remember that, in most cases, the regeneration process uses exhaust heat created under normal engine operating conditions, so the operator won’t even notice it’s taking place. In the event that an active regeneration is necessary, the engine’s control system can raise exhaust temperature to regenerate the filter. In either case, regeneration does not impact machine operation.
Our exhaust filter system has been designed to properly maintain itself without operator intervention while being completely transparent to the operator. Most of the processes with John Deere’s Interim Tier 4 engines happen behind the scenes, which enable operators to use their equipment the same way they used earlier equipment powered by John Deere engines.