Diesel Oxidation Catalyst PM emissions from diesel engines are composed of carbonaceous particles, a soluble organic fraction (SOF), sulfates and adsorbed water. Oxidation catalysts reduce the SOF fraction and have little effect on the carbonaceous portion of PM in diesel exhaust. This limits the reduction in PM emissions that an oxidation catalyst can achieve. The maximum total particulate matter reduction is dependent on the magnitude of the SOF (compared to the carbonaceous portion) in the engine-out exhaust, and is usually between 20 and 30% [Harayama 1992]. Low sulfur fuels and special catalyst formulations are required to limit the catalytic generation of sulfate particulates from sulfur dioxide present in the exhaust gas.
Diesel Particulate Trap Diesel traps filter particulate matter from the exhaust stream with subsequent oxidation of the filtered particulate. Currently available filters for diesel engines are either ceramic wall-flow monolith filters or filter tubes covered with multiple layers of a yarn-like ceramic fiber material. The filter material contains many pores, or small holes, that allow the exhaust gases to pass through while collecting the particulate from the raw exhaust. The particulate matter that is collected by the filter eventually needs to be removed. This process is called regeneration. Two general approaches for regeneration of the trap have been investigated. One approach employed, called a passive system, is the use of catalytic material on the filter which causes regeneration, in a continuous or periodic manner, during the regular operation of the system. The other approach, known as an active system, includes an electric heater or fuel burner to periodically raise the filter temperature, oxidize the particulate and regenerate the trap, as dictated by an electronic control unit. Diesel traps are very effective in reducing PM emissions. Their drawbacks are durability/reliability problems and a decrease in fuel economy due to high exhaust gas pressure drop and, in the case of active systems, due to the operation of the heater or burner. Um, unquote. :-) Keith >Thanks for the info. I've checked up on price for a Catalytic >Converter for an >'85 Golf . . . $200+ . . . so how do you know if the one in the >junkyard is still >good? :-) > >Also, if anybody knows anything about diesel smog checks . . . > >Thanks! > >Bruce > >--- In biofuel@yahoogroups.com, "Steve Spence" <[EMAIL PROTECTED]> wrote: > > you can get cat converters from any auto store. or even good used ones >from > > a wrecking yard. Here in NJ, the state inspections stations have to > > emissions inspect any vehicle, even the smartass that brought in his > > electric conversion. the guy spent 5 minutes looking for the >tailpipe before > > the owner fessed up. > > > > Steve Spence > > Subscribe to the Renewable Energy Newsletter > > & Discussion Boards. Read about Sustainable Technology: > > http://www.green-trust.org > > [EMAIL PROTECTED] > > ----- Original Message ----- > > From: <[EMAIL PROTECTED]> > > To: <biofuel@yahoogroups.com> > > Sent: Saturday, December 14, 2002 1:39 PM > > Subject: [biofuel] Emissions test and catalytic converter > > > > > > > Hi. I have been running my '85 VW Golf on 100% biodiesel since this > > > past August and have been chewing on some emissions issues since >then: > > > > > > First, where can I have my car emissions checked? I have checked > > > with Smog Check stations (in the SF Bay Area) and none of them want to > > > touch a diesel. My car has over 200,000 miles and may need a tuneup. > > > I'd like to get a baseline to see what kind of improvement I'm > > > getting with biodiesel and how much improvement there would be with a > > > catalytic converter. > > > > > > > > > Which leads to the next question - where can a find a good catalytic > > > converter for an '85 Golf? I understand that use of veggie fuels > > > allows you to use catalytic converters that would be otherwise > > > destroyed by the sulfur in petro fuel. How does this work, and where > > > might I find one that will work for my car? > > > > > > Thanks much for your help. I look forward to hearing your replies. > > > > > > Bruce Biofuel at Journey to Forever: http://journeytoforever.org/biofuel.html Biofuels list archives: http://archive.nnytech.net/ Please do NOT send Unsubscribe messages to the list address. To unsubscribe, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
