Gas Cars Emit More Black Carbon Than Previously Thought

[surfingslovak]

http://cen.acs.org/articles/90/web/2012/02/Black-Carbon-Belchers.html" onclick="window.open(this.href);return false;

 

[DaveinOlyWA]

admitting any is more than enough for me

 

[easkag]

http://cen.acs.org/articles/90/web/2012/02/Black-Carbon-Belchers.html

If anyone has any questions about this - let me know. I collaborate with one of the authors - I wrote the software the runs the LII (Laser Induced Incandescence) instrument used to measure the concentrations. Even "clean" ICE cars produce soot (carbon), but it is a much lower concentration than trucks (by "trucks", I referring to the big tractor-trailers). We've concentrated mostly on trucks (as a company) since that is where the regulation is - allowable soot emissions are getting progressively tighter for on-road diesels.

Greg

 

[AndyH]

Welcome Greg!

What's the range of particle sizes from gasoline engines? I found one reference that suggested something in the .005 micrometer range.

Thanks!

 

[easkag]

What's the range of particle sizes from gasoline engines? I found one reference that suggested something in the .005 micrometer range.

Good question AndyH - I'm not sure - LII (the instrument I work on) measures soot concentration (mg/m^3 for example), and infers the soot primary particle size (soot is an aggregate composed of many smaller, primary particles). Most users (almost all) haven't been interested in the primary particle size, and if I understand correctly, aggregate size isn't a regulatory issue (yet). I did ask one of the authors (he specializes in combustion research) and his answer was:

I assume the question is about aggregate size, not PPS. In general, I would say a mean size of about 80 nm for the aggregate mobility diameter (a little smaller than typical diesel particles).

More work is required, especially lab work. For instance, how do the size of particles from GDI engines compare to those from PFI engines?

PPS = primary particle size
GDI = gasoline direct injection
PFI = port fuel injection

Sincerely,

Greg

 

[AndyH]

Fantastic Greg - above and beyond for sure! Thank you!

The thought that came to mind was whether there'd be a benefit to fitting a mechanical filter in the exhaust stream - something like the Donaldson nanofiber media. They get close to 90% removal of 2 nm particles but maybe 50% at about 1/2 a micron.

http://www.donaldson.com/en/filtermedia/support/datalibrary/052024.pdf

Anyone want to build a small filtered 'sniffer' that can be slung below cars and trucks to clean up after themselves?

 

[easkag]

The thought that came to mind was whether there'd be a benefit to fitting a mechanical filter in the exhaust stream - something like the Donaldson nanofiber media. They get close to 90% removal of 2 nm particles but maybe 50% at about 1/2 a micron.

They have something like this for diesels (DPF): http://en.wikipedia.org/wiki/Diesel_particulate_filter

I've been amazed at how well they work (from a filtering point of view) and that they don't introduce too much back pressure into the system. I haven't heard of any attempts to add this to a car/gasoline engine, but this isn't my area (I know just enough to be dangerous about this topic). I've always been of the mind just go electric and bypass any tailpipe emissions, but I realize this isn't practical for large trucks/trains/etc. or even all cars (yet...maybe someday).

Greg