Diesel particulate filters

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Re: Diesel particulate filters

Post by Nereus » Sat Feb 03, 2018 7:06 pm

STEVE G wrote:
Sat Feb 03, 2018 6:22 pm
Nereus wrote:
Sat Feb 03, 2018 4:09 pm
Hmm, cannot agree with that, Steve. The diesel combustion process produces the particles, regardless of the operating temperature of either the engine or the ambient air. The problem is the filter will not re-generate until the exhaust gas reaches around 600 degrees C.
With a cold engine and cold ambient air, fuel atomization is incomplete which produces more soot particles, I think it's something like a magnitude of two or three times from warmer conditions, there is plenty of research available on this, I'd send you a link if I wasn't posting from a small screen!
The FUEL temperature will affect the atomisation, because both the viscosity and surface tension will decrease with an increase in temperature.
Cold ambient air increases the combustion efficiently because it is more dense, hence the use of intercoolers to reduce the temperature. On big marine diesels there is usually some form of fuel heater, and not only when using heavy bunker oil. On small high speed automotive engines I doubt it will make any appreciable difference. Especially with the fuel pressures found in modern common rail injection systems and the electronically controlled injectors.
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Re: Diesel particulate filters

Post by STEVE G » Sat Feb 03, 2018 7:39 pm

Yes, they use fuel heaters on aircraft for the same reason because the fuel can be coming out the wing at about -40C in cruise but when I get in my vehicle at the airport in about half an hour, everything is going to be at about 2C, the engine, fuel and air temperature!
Google something like "reducing diesel cold start particle emissions" and you'll find research papers on the subject that explain the process.

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Re: Diesel particulate filters

Post by J.J.B. » Sun Feb 04, 2018 10:29 pm

Nereus wrote:
Sat Feb 03, 2018 3:56 pm
J.J.B. wrote:Our Discovery has an AdBlue tank but I’ve no idea where you get the stuff from. According to the manual, it needs topping-up at such lengthy intervals that it is done at service time so perhaps I can safely ignore it.
The following is a discussion on the Australian LRO website, J.J.B.:

https://www.aulro.com/afvb/l462-discove ... lling.html
Thanks Nereus, I took a look but it seems they are discussing a different system on the D5.We have one if the last (and best!) D4 Landmark models and the AdBlue filler is located next to the diesel one. Hopefully I won’t need to do anything with it.
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