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Old 01-20-2009, 09:16 PM   #11 (permalink)
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( Can you please post a larger image of your printout, or type out the printout ? I can barely read it. )
I'd love to insert a larger picture. Still haven't figured out how to do a direct insert into the post and can't find a help file to tell me how. Got tips?

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The biggest increase in wear and tear is if you do a lot of EOC - either constant starts from the starter will kill it quicker, or bump starting with clutch will cause it to end it's life sooner.
Because it is an auto. tranny I don't do EOC, just neutral coasting. No extra wear on the starter.

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Hello jjackstone.
What are the one way distances of you most frequent trips?
Have you done any mods to the car/engine?
Most frequent is a five mile trip to work but only when both bicycles are down or heavy rain.
The car is pure stock at the moment and bought used in 2004 with 21500 miles on it. Will be adding synthetic fluids to it in the near future. I don't keep quite the logs a lot of you do but I know that the last time I checked I was averaging 10 to 15% above old EPA numbers. Do have the ScanGauge to check with.


It's been a while but I have actually seen specs that showed either a Honda or Toyota(can't recall which) that put out cleaner air than was going in(which in LA may not be saying much).
JJ

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Old 01-20-2009, 09:43 PM   #12 (permalink)
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Originally Posted by Christ View Post
I had to point this out... while 4kRPM might be 90MPH in high gear, in low gear it might be the equivalent of about 10-20 MPH, and is completely do-able.

What this means: You could potentially drive around town "cleaning" your Diesel Particulate Filter.
Driving around in a low gear and reaching 4000rpm does not require the amount of torque it does as going 90mph. Hence it won't require the same amount of fuel to be burned and thus raise the exhaust gas temperatures as much as going 90. Also the shop manual expects the accelerator to be floored while being held at 4000 rpm on the dyno. So unless I can find a hill to drive up thats steep and long enough to sustain 4000 rpm with my foot to the floor for 20 minutes my DPF will not be cleaned driving at 10-20mph.
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Old 01-20-2009, 10:01 PM   #13 (permalink)
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Ok - so it won't raise the temps as much as going 90 will... that's great. But it will still raise the temps due to the increased flow of exhaust. The question is now "at what temperature will the DPF begin being cleaned?".

Obviously, the idea is to burn the particulates trapped in the particulate filter, therefore, it would have to reach at least the flash point temp of each of those compounds that is being burned.

Doing some research - Wiki.com

Taken from - Diesel particulate filter - Wikipedia, the free encyclopedia

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In addition to collecting the particulate, a method must exist to clean the filter. Some filters are single use (disposable), while others are designed to burn off the accumulated particulate, either through the use of a catalyst (passive), or through an active technology, such as a fuel burner which heats the filter to soot combustion temperatures, through engine modifications (the engine is set to run a certain specific way when the filter load reaches a pre-determined level, either to heat the exhaust gases, or to produce high amounts of NO2, which will oxidize the particulates at relatively low temperatures), or through other methods. This is known as "filter regeneration". Sulfur in the fuel interferes with many "regeneration" strategies, so almost all jurisdictions that are interested in the reduction of particulate emissions, are also passing regulations governing fuel sulfur levels.
Some thinking points:

How do you produce higher amounts of NO2?

Well, I'm not sure about in diesels, but if you really want NO2 production in Gasoline cars, you just lean the mixture a few points. Or advance your timing a few degrees.
Obviously, diesels *generally* don't have "timing", such as gas engines do, however, it is quite possible to lean the mixture of a diesel engine.

How to lean the mixture of ANY engine.

Rev it high. Period. The fuel system of an OEM equipped engine is not designed to provide a stoich ratio (not relevant for diesels) at high RPMS, and cannot compensate for the quality of air at those levels. Friction at this RPM raises engine temps, which in turn insulates combustion chambers to create higher ignition temps and pre-ignition in diesels (pre-pre-ignition, really, since they *generally* run on pre-ignition anyway.)
The resultant higher combustion chamber temp, including the leaner A/F mixture, creates more heat than normal, which could in turn to be used to "regenerate" the particulate filter.

Conn- PLEASE don't misinterpret this as an argument to what you're saying - it's not.

I'm simply saying that at 90 mph or at 20 MPH, the exhaust temp will still increase, just maybe not as much, or as quickly, and that the filter itself relies on heat to regenerate, which is not necessarily caused by a richer mixture, as many would report.
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Old 01-21-2009, 12:26 AM   #14 (permalink)
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Christ no offense, but don't take wikipedia as gospel. It is often changed by people who don't know what they are talking about or change the facts to meet their misconceptions.

For example, the last thing any engine manufacture wants to do is generate any form of nitrous oxides before flowing out of the cylinder. If there is NO2 being formed even more NOx is being formed. Secondly the main thing that plugs up a DPF is carbon soot and the only thing that is really effective at burning it out is lots of heat and O2. Finally sulfur doesn't interfere with regeneration. Sulfur leads to increased soot emissions which will exacerbate the plugging problem however the big problem with sulfur is that it poisons the catalyst that is used to reduce NOx into NO2.

When a regeneration cycle takes place in a modern diesel with a DPF, a small amount of fuel is injected during the power stroke late in the cycle. This is done so that not all of the fuel burns and that which is has little power extracted from it. Its sole purpose is to heat the exhaust as much as possible (Note that diesels normally have extremely low hydro carbon emissions). The fuel that isn't burned hits a dual purpose catalyst that is supposed to burn of the remaining hydrocarbons and also convert NOx to NO2. It also raises the exhaust temps further before getting to the DPF. Any O2 left in the exhaust will then burn off the carbon in the DPF (Also note to enrich the amount of O2 in the exhaust during regeneration cycles EGR is reduced which increases NOx levels produced and thus emitted).


My car was built before common rail injection and can't do a regeneration cycle. The only thing that can get my DPF clean is sustained hard driving. Also the thing that tends to plug it up the most is efficient driving around town.

Normally in the summer my car doesn't plug up at speeds above 45mph and does regenerate the DPF at speeds above 60mph. However in winter with the cooler intake air combined with the lower btu content of winter diesel fuel my car doesn't plug at 70mph. The only thing I can do to start regenerating it is to floor it up long steep hills at 80+.

Finally my car driving in 1st at 4000 rpm is going to generate about 5 to 7 psi of boost. This is going to force so much excess air into my cylinders that my exhaust temperatures will drop below what they would be driving my car around in drive. It will also burn more fuel, wear out my engine, and create more CO2 not to mention cost me a lot more money. don't take wikipedia as gospel. It is often changed by people who don't know what they are talking about or twist the facts to match their misconceptions.

For example, the last thing any engine manufacture wants to do is generate any form of nitrous oxides before flowing out of the cylinder. If there is NO2 being formed even more NOx is being formed. Secondly the main thing that plugs up a DPF is carbon soot and the only thing that is really effective at burning it out is lots of heat and O2. Finally sulfur doesn't interfere with regeneration. Sulfur leads to increased soot emissions which will exacerbate the plugging problem however the big problem with sulfur is that it poisons the catalyst that is used to reduce NOx into NO2.

When a regeneration cycle takes place in a modern diesel with a DPF, a small amount of fuel is injected during the power stroke late in the cycle. This is done so that not all of the fuel burns and that which is has little power extracted from it. Its sole purpose is to heat the exhaust as much as possible (Note that diesels normally have extremely low hydro carbon emissions). The fuel that isn't burned hits a dual purpose catalyst that is supposed to burn of the remaining hydrocarbons and also convert NOx to NO2. It also raises the exhaust temps further before getting to the DPF. Any O2 left in the exhaust will then burn off the carbon in the DPF (Also note to enrich the amount of O2 in the exhaust during regeneration cycles EGR is reduced which increases NOx levels produced and thus emitted).

My car was built before common rail injection and can't do a regeneration cycle. The only thing that can get my DPF clean is sustained hard driving. Also the thing that tends to plug it up the most is efficient driving around town.

Normally in the summer my car doesn't plug up at speeds above 45mph and does regenerate the DPF at speeds above 60mph. However in winter with the cooler intake air combined with the lower btu content of winter diesel fuel my car doesn't plug at 70mph. The only thing I can do to start regenerating it is to floor it up long steep hills at 80+.


Combustion in a diesel is quite different than a gasoline engine. Unless over fueled or smothered by excessive EGR, atomized fuel droplets fly through compressed heated air surrounded by a boundary layer of mixture that is near optimum for combustion. They continue until they burn themselves out of existence. This is why a diesel can run air fuel mixtures of 20 to well over 100 to 1 and gas engines can't. Assuming you have about 15% excess air in both cases, using the same amount of fuel in a diesel with higher air to fuel ratios drops your exhaust gas temperatures in comparison to a lower ratio.


Finally my car driving in 1st at 4000 rpm is going to generate about 5 to 7 psi of boost. This is going to force so much excess air into my cylinders that my exhaust temperatures will drop below what they would be driving my car around in drive. It will also burn more fuel, wear out my engine, and create more CO2 not to mention cost me a lot more money.

Not going to happen...
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Old 01-21-2009, 12:27 AM   #15 (permalink)
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Originally Posted by jjackstone View Post
I'd love to insert a larger picture. Still haven't figured out how to do a direct insert into the post and can't find a help file to tell me how. Got tips?
  1. Post the picture anywhere on line. (eg. Image hosting, free photo sharing & video sharing at Photobucket).
  2. Get the web address of the picture (by viewing it in your browser).
  3. When you post, click the "Insert Image" button - []
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Old 01-21-2009, 02:43 AM   #16 (permalink)
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Conn- Believe me, I don't take it as gospel even remotely. I seldom quote or even read anything from Wiki. That particular section was, however, close enough to what I had already known from working on trucks, and was close to what I had read in reports, etc. So I elected to use it instead of searching for a more reputable source.

By the way, gas engines CAN and HAVE run at ratios well in excess of 20:1. FYI. In fact, 60:1 is more likely possible for Gasoline Direct Injection, and 100:1 or better has been reported (I have yet to actually see it documented) in cases where mixture manipulation has been used. (Mixture manipulation refers to the same concept used in Honda's CVCC engines, where dual mixtures were used. One was extremely lean, the other, much smaller volume, was extremely rich. The rich mixture ignites with less spark energy, and the flame front from it ignites the much leaner mixture... timing was critical for engines of this type for maximum efficiency.)
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Old 01-21-2009, 10:31 AM   #17 (permalink)
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Old 01-21-2009, 10:48 AM   #18 (permalink)
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ConnClark,
I'd just point your land yacht up one of your mountain roads and let it rip a couple times a year. It should get plenty hot!
I don't think they meant having your car at anywhere near full throttle on a dyno for 20 minutes. I doubt many dyno's can absorb that much energy (100hp for 20 minutes!) and probably something under the hood would melt, catch fire, or atleast half the life would be cooked out of many rubber or plastic parts...
Even free wheeling at 4000rpm for 20 minutes should have the exhaust glowing brightly which I think is what they meant to have done...
Ian
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Old 01-22-2009, 01:48 PM   #19 (permalink)
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KJSatz -



I think if you have a "one wire" 02 sensor that depends on the exhaust heat to get hot enough to work (like mine), it can cool off if you do a lot of bump starts. If the 02 sensor gets too cold, the ECU/PCM will go into open-loop mode, which is not as fuel efficient. If you have a "four wire or more" 02 sensor, then it is probably self-heating and will stay hot when the engine is off.

My car has two 02 sensors. The second one is post-cat and does have 4 wires. If I had my druthers, I would convert my 1-wire 02 sensor into a 4-wire, just like my other sensor. That would get me into closed-loop mode faster.

CarloSW2
You need a front belly pan and grill block. Everything under the hood will stay 150f. Including the battery which I just had to replace.

So far I've replaced all the motormounts and recently the battery went south.

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