We've been talking more and more about petrol particulate filters in recent years, but how do they actually work?
A particular term has been creeping into more and more car reviews in recent years - ‘petrol particulate filter’. These aren’t as well known asdiesel颗粒过滤器（DPFS）大约更长，从2009年开始就变得无处不在。
Particulates from petrol engines have been tightly controlled since the days of Euro 5. However, the replacement of the old NEDC (New European Driving Cycle) lab test cycle with the tougherWLTP (Worldwide Harmonised Light Vehicles Test Procedure)regime from Euro 6c onwards (joined by RDE, Real Driving Emissions, from Euro 6d) has made it much harder to comply. For a lot of cars, particulate matter emissions needed to be reduced drastically, leading to the rise of the OPF.
When exhaust gasses make their way through the device, the honeycomb filter traps excess nitrous oxide, carbon monoxide and hydrocarbon particulates. Due to the high temperature of the filter, these are all burned off, giving off a little water, nitrogen and carbon dioxide in the process. Hey presto - a decrease in particulates of around 90 to 95 per cent.
Diesel particulate filters have a reputation for getting clogged over time, particularly on cars that are used mostly for shorter, lower-speed journeys. With OPFs, this isn’t as much of an issue. As a kick-off, higher petrol engine (and therefore exhaust) temperatures make them more effective at burning stuff off, and secondly, petrol engines usually emit lower volumes of particulates.
但是我们离题 - 总结，不，汽油颗粒过滤器不需要任何维护。除非您对我们的下一个观点感到困扰，否则您可能会及时忘记它。或者一开始就不知道。
Widespread adoption of OPFs is good news from an environmental perspective - we can’t deny that. But it’s hard not to be sad about the side effect of quieter engines. The reason for the noise reduction is simple - the particulate filter is an additional restriction, and restrictions in an exhaust system mean a more muffled sound coming out of the tailpipe.
As noted by then-Aston Martin首席工程师马特·贝克尔（Matt Becker）在几年前与CT交谈时，OPF使我们很难在2010年代添加我们习惯的所有人造流行音乐和刘海。在某些情况下，这不是一件坏事。这Jaguar F-Type R例如，可以说听起来更好的后FFS，其曾经过多的机枪般的排气性特征大大降低了。现在，这一切都是关于可爱的V8 Rumble，它仍然可以听到。
For a lot of cars, though, the news is less good. OPF-equipped second-generation奥迪R8s (facelift onwards) are noticeably more muted than their predecessors. To make matters worse, the closely relatedHuracan Evocan use the same engine without filters, withLamborghini取而代之的是组合端口和方向注入以减少排放并遵守规则。
不久之后，将这个问题重新构想为“什么汽车don’thave particulate filters?” Starting in late 2017, PSA Group installed OPFs on all its GDI (gasoline direct injection) petrol engines.Volkswagenstarting fitting OPFs to all its cars in 2018, as didBMW.Mercedes,Volvo,座位,AudiSkodaare among others using them.
Supercars and luxury sports cars aren’t immune, either. Aston Martin models powered by twin-turbo V8s, which are sourced from Mercedes-AMG, have used OPFs for a little while now.保时捷911包括GT3在内的模型是OPF用户。我们已经讨论过的奥迪R8，甚至法拉利也参加了该法案，从F8 Tributo的3.9升双涡轮增压V8开始。
From a technical standpoint, yes you can. Quite easily, in fact. Myriad companies offer OPF delete pipes for stacks of different cars. However, there are a couple of caveats. Firstly, any such modification would need to be accompanied by some ECU fiddling to prevent the missing OPF sensors from giving a fault code or even forcing the car into limp mode. Plus, you might have noticed a warning in the fine print on some websites, usually saying something along the lines of ‘track use only’.
OPF是您汽车排放控制系统的一部分，因此，由于安装了decat管来抛弃催化转换器（或抛弃DPF），如果发现，OPF删除可能会使您在合法的热水中留下。VAG Tuning Company Revo已经反对OPF删除。这家英国公司的网站补充说：“我们预计将其删除与DPF一样违法，因此，删除GPF并不是Revo支持的过程。”
See also: The Pros And Cons Of Different Exhaust Materials
That’s not to say the solution is hopeless if you want to retain road legality. If you focus on removing the restrictions you’re actually able to, there are still aural improvements to be made. We’ve heard plenty of decent results from OPF-back or axle-back exhaust setups, for instance, and in time aftermarket companies will only get better at working with OPFs, both for exhausts and other modifications.