Clean diesel vs Hybrid research paper complete with sources of info

The regen cycle is based on many parameters, such as idle time, load, temp, etc. The extra fuel is then injected to cause the Diesel Particulate Filter to "burn off" the accumulated soot. There is no set rule on how much extra fuel is required

If the vehicle is used always in town/city driving with plenty of idle time, then the DPF warning light will turn on instead. You need moderate to heavy loads - eg highway driving mostly loaded - to properly burn off the soot

In city use, the DPF must be manually regenerated. The procedure varies by engine maker, it can take 30-60 minutes.

I think its funny (Not haha, but ironic) that folks here remove the DPF and stick in that tuner that allows clouds of black smoke. In many EU cities, they are mandating that city buses and trucks be retrofitted with SCR/DPF, and any hint of smoke is a hefty fine on the spot

If these "tuners" were so smart, you'd see the engineers beating a path to their door to get "educated"

 

I cant speak for diesel cars. But pickup trucks tend to gain an average of 5-6mpg some even more when deleting the DPF.

Actually Fords engineers have collaberated with the tuner I have mentioned on it and a few others as well. By the way your info on manual regens is really outdated. In the case of light trucks all regen is automatic whether its city or highway driving. Semi trucks are the only one that can force a manual regen.

 

I only have experience with highway tractors, or "real" trucks

Do you have any evidence of an independent "tuner" having engineers consulting with? It would be like the janitor at a petrochemical plant telling me how to do my job

As far as tuning, its easy to tune for higher mileage or more power. Small cars in the 70's easily got Prius fuel economy, by lean tuning. But lean tuning dramatically increases NOx emissions, which is a direct smog component

As an example: The early Honda Insight "lean burn" got pretty remarkable fuel economy, but it put out a lot of NOx due to the lean burn nature of the motor.

So its a tradeoff. You can take an early 1990's Dodge with the Cummins and a stick shift, tune it for pretty amazing fuel economy and modest power improvement. But it would pump out a lot of PM, dioxin, and NOx

So imagine if most of the vehicles on the road were just like it. If you have been to the EU on business, you would have noticed a pretty obvious difference in air quality. That is, the air quality in North American cities was a lot better

The majority of vehicles on the roads in the EU were diesel, without emissions controls until fairly recently. Now there is a big rush to improve air quality in major cities like London, as a result of all those emissions. Hence the mandatory retrofitting of older diesel buses and trucks to use SCR/DPF

 

I do have evidence yes. However without his permission I'm not going to release info.

Actually in most cases these tuners show reductions in NOx emissions vs DPF equipped trucks.

I have a brother that is in the EU, china, brazil, and even Iraq and afganistan weekly on business. He states that with the exception of china the air quality in the EU and other countries is comparable to any large city in the US

 

The air quality in Geneva is fair to good. The air quality in London is usually pretty bad. Singapore is usually fair to bad

 

As in .... 25% ? Wow

 

Yes

 

So, with the DPF removed, how are the PM, NOx, and NMHC emissions?

 

With the DPF removed and proper tuning all have been reduced. I dont have the figures in front of me. I will get them later today.

 

You don't have to take my word for it. I provided a link to the CARB ML350 BlueTec cert sheet and the LEV II LEV/ULEV/SULEV standards are available at Emission Standards: USA: Cars and Light-Duty Trucks - California (Table 3). All of the 50-state light-duty diesel vehicles are ULEV and are closer to the SULEV standards than they are to the ULEV standards.

You're implicitly misrepresenting the implications of the weekend ozone effect. There are no recommendations to increase NOx emissions that I'm aware of, just that HC emissions need to be reduced relatively more than NOx emissions, at least until the anthropogenic HC emissions become trivial. The Tier 2 regs do just the opposite of that compared to Tier 1.

My point is that, in my opinion as an air quality forecaster, using the emission category to which a vehicle is certified to conclude the air quality impact of the vehicle, or class of vehicles, is misleading because the emission standards are non-ideal from an air quality perspective.

 

Really? And how is that possible? Magic??

 

To be fair to Honda, it had a lean-NOx catalyst as well. It basically stores nitrogen oxide on the catalyst material, then periodically cycles the engine to the rich side to convert the stored NO to nitrogen and oxygen.

Still, it produced more NOx than the Prius as some didn't get stored. The Prius always runs stoichometric.

The new Insight uses Honda's L-series 8-valve engine (i-DSi) which is stoichometric, but with two spark plugs per cylinder and two sparks per cycle. Honda claim it has as good fuel economy as the lean-burn equivalent while having better (lower) NOx emissions.

A better example would be the constant references to 1980s vehicles which often were tuned for low fuel economy, but high NOx formation, by tweaking the carburettor toward the lean side.

I'm not sure I believe simultaneous low NOx formation and low fuel consumption in diesels. Diesels do not run stoichometric, they are always lean-burn, as they are typically not throttled - the same amount of air is pumped on every cycle with the amount of fuel varied. If there is excess oxygen and the heat of combustion is sufficient - which goes up the more free oxygen there is - there is enough energy to break up the nitrogen molecules in the air, which burn with the oxygen to form NOx. You can certainly design the vehicle with more EGR to reduce cylinder temperatures (by removing free oxygen), but I don't think you can do that through mods. Maybe when chipping.

I would guess, without seeing the example, that the EPA new-vehicle testing procedure is not being followed correctly. Just testing at idle can show different results from performing a proper driving cycle. See Drive-cycle economy and emissions measurement on www.fuelsaving.info.

 

Tuning makes it possible. As I said I wont go into further detail without permission as it is propriety information

Tuning has come leaps and bounds from what it was years ago. There is far more involved than the messing with EOT tables it was 10 years ago

 

Correct, and Honda, like you stated, now uses different technology to achieve results just as good with lower NOx emissions. As technology improves, we can have our cake and eat it too (Lower emissions, better performance, and better fuel economy)

Many articles have touched on this. This is a good read

http://www.thepep.org/ClearingHouse/docfiles/ECMT NOx.pdf

With older non-emission carb passenger cars, it was fairly easy to tune the vehicle for great performance and decent fuel economy. However, emissions were through the roof.

I personally would not want to drive a carb vehicle any more. Its nice to have a modern vehicle where you just hop in, turn it on, and go. No stumbling, no warm up, no choke to fiddle with, etc

Correct. The SCR/DPF will stop working altogether without the introduction of more fuel. With the SCR/DPF removed, it is patently impossible to have lower PM and NOx

Unless magic is involved

Along a similar line, it would be like removing the catalytic converters from my FJ Cruiser, and expecting *lower* CO and NOx emissions

I enjoy discussing chemistry. But perhaps we should keep it a bit more simple for the new members?

If the SCR/DPF is removed, the vehicle will automatically fail the EPA emissions test

 

So your assertion is that someone has figured a way to "tune" the vehicle to perform better on all emissions testing without a filter than the factory vehicle with a filter?

But it's secret, so no one can know about it, and automakers apparently have no interest in or knowledge of this "tuning" that would save them billions of dollars. Right.

 

Actually with the exception of the portion that states the DPF must remain intact the epa testing was followed too the letter.

Of course it will fail the government mandated testing. the government mandates the DPF is intact

 

How does removing the SCR/DPF and "tuning" make it possible?

The present fuel injector pulse timing is required to get optimal life and efficiency from the SCR/DPF. Even the quality of oil used has a huge impact on SCR/DPF life: not all CJ-4 oils are created the same, and depending on additives used and how much oil is burned, the SCR/DPF will clog and require replacement sooner

This is like when folks tell me they can lower the emissions on a gasoline motor by removing the catalytic converters. Its simple chemistry.

For a diesel engine, one can consider the soluble organic fraction of PM, the HC, CO, and NOx. A diesel oxidation catalyst will take care of the CO, HC, and SOF of PM. To keep it very simple:

CO + O2 - CO2
HC +O2 - CO2 + H2O

There will also be NO - NO2 conversion, which assists the downstream DPF to maintain longer periods between regeneration. The extra fuel is injected to increase exhaust temp, to oxidize the trapped particulates

So, how does one achieve the levels of HC, CO, NOx, and PM at the same levels using a SCR/DOC and DPF, but without the SCR/DOC and DPF??

 

Ah

Explain please how the chemistry works then. I'm not a scientist, only a humble engineer. I would like to know how NOX, PM, and other harmful byproducts of combustion can be selectively oxidized without a catalyst.

 

Automakers have this knowledge already and do collaborate with these "tuners" However with the current mandates in place they are stuck with what they have. Have you ever known and government agency especially the EPA to look beyond the end of their nose?

You dont think injector PW and injection timing can be changed along with multiple other things by ECM programming? You have alot to learn.:rockon:

 

With billions of dollars at stake, even the survival of their INDUSTRY at stake, two words: bull and s***

<sigh>

Yes, I am WELL AWARE that you can remove the emission control devices and change many operating parameters.

But you have not answered the simple chemistry question: how do you selectively oxidize HC, soluble PM, NOx without a catalyst?

If the global automotive industry could achieve that magic trick, without the use of expensive and failure-prone catalysts, all while achieving 30-40% increases in fuel economy, it would not only save the global automotive industry billions ... no, TENS of billions of dollars over the next decade, but even revolutionize the entire industry

But as a humble chemical engineer, I would still like to know this secret magic trick of selectively oxidizing chemicals without the use of catalysts. See, the chemical industry, especially the petrochemical industry, would be revolutionized overnight with such a discovery

Not only would the environment become much cleaner, but production costs of raw feedstocks would be a fraction of what they are now. This secret magic discovery would not only rescue the global economy, but create untold jobs for billions

Just asking, that's all