jimh425 wrote:
DEF can increase the combustion temperature according to Volkswagen, for instance. http://www.volkspage.net/technik/ssp/ssp/SSP_330.pdf At least, I'm assuming their additive is the DEF.
System with additive
This system is used on vehicles where the particulate filter is installed away from the engine. Due to the distance the exhaust gas has to make from the engine to the particulate filter, the required ignition temperature for combustion of the particulates can only be reached with the introduction of an additive.
The question is "do other additives" help as well. If so, in extreme circumstance like slow driving would it be advantageous to change the amount of additive and/or change the driving method if possible to prevent a potential clogged dpf issue.
However, NEVER add DEF directly to the fuel tank or expensive, non-warranty damage can result. It should only be added to the DEF tank and never used as a fuel additive.