С микроба
viviandr писал(а):Сажевый фильтр имеет специальную конструкцию для накопления сажи. Когда сажи становится много, то растет сопротивление в выпускном тракте. Мозги мотора получают информацию с датчиков давления, которые установлены на DPF (трубки идут к датчикам давления, т.к температура там высокая, что б они (датчики) не сгорели) и начинает процесс регенерации DPF, путем повышения содержания кислорода в выхлопе и полного выжигания накопившегося углерода (сажи). Для того чтобы не пережечь слишком сильно DPF, на нем устанавливают датчик температуры. После DPF всегда следует DOC катализатор, который доокисляет получившийся СО до углекислого газа (СО2) Надеюсь принцип понятен всем и сомнений , что у нас на Грандах нет DPF не осталось.
Кусок из wiki :
For diesel engines
For compression-ignition (i.e., diesel engines), the most-commonly-used catalytic converter is the Diesel Oxidation Catalyst (DOC). This catalyst uses O2 (oxygen) in the exhaust gas stream to convert CO (carbon monoxide) to CO2 (carbon dioxide) and HC (hydrocarbons) to H2O (water) and CO2. These converters often operate at 90 percent efficiency, virtually eliminating diesel odor and
ing to reduce visible particulates (soot). These catalyst are not active for NOx reduction because any reductant present would react first with the high concentration of O2 in diesel exhaust gas.
Reduction in NOx emissions from compression-ignition engine has previously been addressed by the addition of exhaust gas to incoming air charge, known as exhaust gas recirculation (EGR). In 2010, most light-duty diesel manufactures in the U.S. added catalytic systems to their vehicles to meet new federal emissions requirements. There are two techniques that have been developed for the catalytic reduction of NOx emissions under lean exhaust condition - selective catalytic reduction (SCR) and the lean NOx trap or NOx adsorber. Instead of precious metal containing NOx adsorbers, most manufacturers selected base metal SCR system which use a reagent such as ammonia to reduce the NOx into nitrogen. Ammonia is supplied to the catalyst system by the injection of urea into the exhaust, which then undergoes thermal decomposition and hydrolysis into ammonia. One trademark product of urea solution, also referred to as Diesel Emission Fluid (DEF), is AdBlue.
Diesel exhaust contains relatively high levels of particulate matter (soot), consisting in large part of elemental carbon. Catalytic converters cannot clean up elemental carbon, though they do remove up to 90 percent of the soluble organic fraction[citation needed], so particulates are cleaned up by a soot trap or diesel particulate filter (DPF). A DPF consists of a cordierite substrate with a geometry that forces the exhaust flow through the substrate walls, leaving behind trapped soot particles. As the amount of soot trapped on the DPF increases, so does the back pressure in the exhaust system. Periodic regenerations (high temperature excursions) are required to initiate combustion of the trapped soot and thereby reducing the exhaust back pressure. The amount of soot loaded on the DPF prior to regeneration may also be limited to prevent extreme exotherms from damaging the trap during regeneration. In the U.S., all on-road heavy-duty vehicles powered by diesel and built after January 1, 2007, must be equipped with a catalytic converter and a diesel particulate filter
DPF должен выглядеть подобным образом
dpf.jpg
Доступно и доходчиво
http://www.tdiservice.ru/technology/dpf/На заборах тоже много чего пишут, а рукой потрогаешь - доски...
Добавлено: 25 авг 2011, 21:52