Hopefully Ford and Ram does move the dpf regen to the exhaust, thus eliminating some fuel bypassing the rings. If not we will be switching to GM. This article may explain some dpf regen questions. The 9th glow plug is in exhaust pipe because GM injects in exhaust to regen the DPF filter.
Diesel Particulate Filters
A diesel particulate filter, also known as a DPF, is an emissions reduction device designed to remove diesel particulate matter or soot from the exhaust gases of a diesel engine. This particulate matter is the byproduct of incomplete combustion mostly made up of unburned hydrocarbons (Hc) and the non-combustible residue of lubricating oils. These particles also provide a vehicle for the many trace chemicals that are also produced by diesel fuel and the combustion process which are known to cause environmental problems and believed to cause public health issues. The DPF is designed to physically trap, store and then oxidize or burn off particulate matter effectively reducing particulate matter emissions. This process of burning off the collected particles is called regeneration. What remains after the regeneration process is ash which is the noncombustible residue of engine lubricating oil. The use of ultra low sulfur fuel (ULSD) and low phosphate engine oils is required on DPF equipped engines. Sulfur and phosphates will foul the DPF quickly causing performance loss and dramatically reducing the life of the DPF.
It is important to note that the chemistry shown is simplified to show the basic function. The chemistry that takes place in an after treatment system is complex, varies between manufacturers and is still being explored. You need to understand that the process of burning off the particulate matter and determining what chemicals and gasses that exit the tail pipe involves several chemical reactions, not just heat. In fact, depending on the chemical changes that take place, the temperatures require to burn off particulate matter can be reduced. Most after treatment systems combine a diesel oxidation catalyst or a diesel oxidation converter with the DPF and both may be"catalyst-coated." The application of a base, or precious metal coating, to the surface of the catalyst and the filter will alter the chemistry of the exhaust that can reduce the ignition temperature necessary for oxidation of the particulate matter. This passively burns off some of the soot during normal operation of the vehicle and helps in reducing the volume of soot that reaches the DPF. Used in-line with a DPF, a diesel oxidation catalyst will also help boost exhaust temperatures required for active regeneration. A system like that of the 6.4L PSD, extra fuel is added to the exhaust gasses by injecting fuel into the cylinders during the exhaust stroke. The added fuel is burned off in the catalyst effectively raising the exhaust temperature to heat the DPF during active regeneration.
Worth noting- Urea injection, also called Selective Catalytic Reduction (SCR), works by an ammonia-like acid being injected into a special catalyst to reduce NOx in diesel emissions. This will further complicate after treatment systems and increase maintenance for the operator in that urea it will add another fluid to be regularly maintained.
