For 2014, John Deere 5000 Series tractors must meet the EPA Interim Tier 4 (IT4) emissions mandates. These mandates require the reduction of nitrogen oxides (NOx) and diesel particulate matter (PM). NOx is formed by higher temperatures in the cylinders during combustion, and particulate matter is essentially diesel fuel that didn’t fully burn during the combustion process.
NOx can be reduced by cooling exhaust gasses by a process called Exhaust Gas Recirculation (EGR). Another component of diesel exhaust, carbon monoxide, can also be reduced by a Diesel Oxidation Catalyst filter called DOC.
Particulate matter can be reduced as well by combining a Diesel Particulate Filter (DPF) to the DOC. The exhaust filter reduces particulate matter without requiring any operator involvement.
The DOC (1) reacts chemically with exhaust gases (2 = exhaust in, 3 = exhaust out) to reduce carbon monoxide, hydrocarbons, and some particulate matter.The DPF (4) is constructed of ceramic porous channel walls, trapping and holding any remaining particulate matter.
Both the DOC and DPF are designed to last the life of the tractor. The DOC requires no regular maintenance. The DPF, which traps particulate matter and is cleaned through the automatic filter cleaning processes, also collects and retains residual ash.
Ash is formed from additives in diesel fuel and engine oil, and is a metallic compound that cannot be removed through the automatic filter cleaning process. At some point, the DPF will require professional servicing to remove the ash buildup. Based on tractor usage, this generally occurs between 4500 and 5000 hours.
Depending on the load that the tractor is under, as well as surrounding temperature, humidity, and engine speed, the DPF may build up with particulate matter, thus requiring cleaning. Filter cleaning is determined by one of three factors:
- A prescribed time-based estimation of needed filter cleaning
- DOC/DPF pressure sensors
- A particulate matter buildup estimation based on load conditions
Once one of the three parameters has been met, filter cleaning will occur.
There are three different types of filter cleaning processes:
- Passive filter cleaning
- Active filter cleaning
- Parked filter cleaning
Passive filter cleaning occurs naturally when the engine is generating enough heat to oxidize particulate matter. This automatic process occurs continuously during normal operating conditions. No tractor icons or symbols appear on the dash during passive filter cleaning.
Passive filter cleaning requires no operator involvement, and there is no interruption to tractor operation.
If conditions (temperature, load, or speed) for passive filter cleaning cannot be achieved, then PM is removed using active filter cleaner. In the diagram, 1 = injection unit, 2 = exhaust, 3 = fuel supply, and 4 = metering unit. To achieve the required conditions, Exhaust Temperature Management (ETM) manages the initiation and duration of Active Filter Cleaning. An icon on the dash indicates when ETM and Active Filter Cleaning have been initiated. ETM can adjust numerous engine parameters and/or inject a small quantity of fuel into the exhaust stream for a short duration.
The fuel turns to vapor and chemically reacts with the catalysts in the DOC to create heat to oxidize PM.It is important to note that at no time is the fuel in the DOC/DPF ignited, and there is no flame within the DOC/DPF.Like passive filter cleaning, active filter cleaning requires no operator involvement, and there is no interruption to tractor operation.
In some rare instances, a parked filter cleaning may need to take place. Most likely the only time a parked filter cleaning will need to occur is when automatic filter cleaning has been disabled within the CommandCenter™ for an extended period of time and multiple warnings to engage filter cleaning were ignored.
Additionally, when the automatic filter cleaning process has been deliberately interrupted multiple times, or if active filter cleaning has failed numerous times due to a failed component, a parked filter cleaning may be requested. In these rare instances, the CommandCenter will prompt the operator to park the tractor and start the filter cleaning process.