а вот вам, пока вы ищете что-то про PD, то что на самом деле писали про переход на CR
In an effort to improve efficiency and emissions, Volkswagen Auto Group recently announced that it would be switching to common-rail turbo diesel technology, starting with a new wave of diesels beginning in 2007 - perfectly timed to meet new tougher North American emissions regulations that will also see cleaner diesel fuel introduced across the continent. Wait… Volkswagen, the industry leader in diesel sales, not on the forefront of diesel technology?
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But for all of its landmarks and sales, VW will be moving away from its Pumpe-Duse engine technology which it established nearly eight years ago in order to meet increasing emissions standards from Europe, as well as within North America. If you havent already heard, the U.S. Governments Tier II Emissions regulations have had manufacturers scrambling to figure out a way to improve their diesel particulate ratings before the 2007 deadline. Currently, no diesel-powered vehicle currently on sale in North America can meet these standards. Given the fact that a good chunk of VWs sales are in the diesel market, its no wonder theyre switching.
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Another factor involved in cutting emissions, particulate filters, can be fitted to common-rail diesel-powered vehicles, but they cannot be fitted to unit-injection diesel vehicles. The reason, unsurprisingly, has to do with common-rail technology and its ability to inject fuel during the post-combustion phase. The small secondary burst of fuel allows the temperature of exhaust fumes to rise, allowing for the filtration of emissions-causing particles. Particle filters are able to remove up to 80 percent of particulate emissions and would certainly help VW sneak by lofty tailpipe regulations.
и более подробно чуть более техническим языком
Around the year 2001 VW/Audi introduced the PD engine. Not a new design in theory as this type of diesel injection had been used for many years in marine applications but it hadn't come this far in terms of control. A unit injector is fitted per cylinder. The injector includes its very own high pressure pump (internal pressures of 2050 bar on the 1.9 and 2200 on the later 2.0 piezo injectors). The injector and the pump is run off the camshaft, with a cam lobe pushing down and generating the pressure. The solenoid controls the amount of fuel that is required, timing if the injector is mechanical still.
This is the fundamental problem with the PD engine and what will eventually lead to its sad demise. With new legislation all diesel engines will need to run a DPF to meet Euro 5 regs (IIRC). To activate self regeneration, a very late cycle of injection needs to be added; the fuel is injected post combustion which increases exhaust temperature which starts the regeneration process. As the timing of this injection is controlled by a mechanical factor, i.e the camshaft, there is only so much that can be done. The PD engines fitted with the DPF have a different camshaft with an additional profile to the lobe; this gives another fuel injection post combustion for regeneration. However this all has to happen within 360 degrees of camshaft rotation. For there to be time for the injector to work again for the next cycle, this obviously has some serious limitations.
как таковая PD значительно более надежная и значительно менее требовательная система, PD впрыск откатан еще с 30хх годов,... и очень жаль что экологи режут на корню красивые и надежные моторы
) никогда не возвращаются к этим моторам и не пишут хвалебные отзывы на форумах. И еще, у 1.9TDi 93-01 годов 90/110 лс только один серьезный недостаток - несоответсвие экологическим нормам евро 3 и выше, что и завершило производство этих мотров. Кстати, VW один из всех пытался внедрять насос-форсунки на легковом дизеле, но признав почти официально неудачу с этими моторами все равно пришел к впрыску common rail, который намного интереснее и, имхо, надежнее НФ. Спасибо за внимание.
С 2000 по 2009 год. Хз скоко миллионов движков разлетелось по свету. А на CR перешли исключительно по экологическим требованиям.
