VW Faces $17B Fine for Emissions Scam

GM also passes the EPA with their diesels. The Cruze is going to be the only diesel car available next year.
I'm guessing GM has no problem using the loop holes in EU regulations.

Should be pointed out that the newest diesels in the study were 2015MY.

 

Thank you for further solidifying my point.

 

Apparently, diesel cars in Europe that are certified to Euro 6d-temp have NOx emissions that on average are well below the regulated limit (80 mg/km), and nearly as low as the petrol cars average...

New diesels found to be 71% cleaner than petrol models | Environment News

 

Ah I don't want to believe in it!

 

For at least the last twenty years or more, there has never been any doubt whatsoever that Diesel engines can be made to be just as clean as gasoline engines are. There is no real controversy about that.

But it is complicated and expensive. That's why they cheated.

 

It is still a relatively new technology that is improving in costs and effectiveness with time. Which couldn't have been made until strict emission standards and USLD were in place.

VW cheated in the beginning because of the cost it would add to their popular diesel Jetta, and because having to use DEF was seen as a negative by the public. They kept cheating because of momentum, and the advantage it gave them. BMW and GM both met the regulations while maintaining performance and fuel economy without cheating in the US.

 

My understanding is the SCR requires:

• AdBase a urea based, consumable fluid, 20 gallons diesel to 1 gallon fluid
• Higher fuel consumption as a fuel rich cycle is needed

I'm not sure about whether or not this also requires a larger, more effective particle filter.

Bob Wilson

 

I believe you are wrong on the higher fuel consumption. It is a mostly passive exhaust treatment, like a gasoline car's 3-way cat. It just requires the addition of DEF to deal with the higher levels of NOx. LNT systems on the other hand require regen cycles that burn extra fuel to raise the exhaust temps.

In the early days of improved diesel emissions, adding DEF was seen as a negative by the public because it was an additional maintenance item. One truck company nearly went under, or maybe did, because they insisted on finding a solution that didn't use SCR.

So VW didn't want SCR on the Jetta for those reasons. Honda tried to introduce a diesel Accord after cancelling the first hybrid without using SCR for the same reasons. They didn't cheat, so gave up, as would Mazda did more recently. The larger, heavier Passat managed to get near equal EPA fuel economy numbers using SCR to its sibling using just LNT.

 

For the AdBlue ratio, I was using sources like this:
AdBlue What diesel vehicle owners need to know

When the fuel is burned by the engine, AdBlue is injected into the SCR catalyst in order to convert the NOx into a less harmful mixture of nitrogen and water vapour. The solution is stored in its own tank, separate from the diesel, before being added to outgoing exhaust gas by a dosing control system that supplies enough AdBlue to make up 2–6% of the total fuel consumption. In the SCR catalytic converter, the urea present becomes ammonia when heated, reacting with the NOx in the emissions to convert the pollutants into nitrogen, water, and a small amount of carbon dioxide —elements that are already natural to the air that we breathe.​

I also understand that a typical system looks like:

Source: What is SCR? | Diesel Technology Forum

The extra fuel burn occurs when the particulate filter has to 'burn out' the soot. Not technically part of direct NOx treatment, it is needed prevent the catalyst from being rendered inoperable due to a layer of soot.

Regardless, I'm always curious. Do you have other sources?

I agree with you that the failed VW system ... well it was a fraud. Worse, it fooled other manufactures using SCR that they could not compete with VW cheat.

Bob Wilson

 

Regulations required DPF before ULSD became available in the US. Diesels were equipped with them before regulation NOx levels required SCR or LNT. So the fuel used to regenerate them isn't part of the SCR process. I'm sure the SCR benefits by being kept cleaner, but then the 3-way cat of a DI gasser likely would benefit from an exhaust filter too.

LNT requires its own regen cycle that may not coincide with the DPF's.

 

Maybe the answer lies in that 2-6% AdBlue per fuel? In reality no car consumes that much AdBlue, it's more like 1% of fuel. So I have a feeling that other measures to reduce NOx also apply, such as EGR, injector timing and maybe even some of the principals of LNT?

 

And a quote from that article:

Emissions Analytics says that in around 10 years the majority of diesels on the road are likely to be of the cleaner variety and that the current figures suggest a switch to petrol vehicles may not deliver the desired long-term air quality improvements.
​

We will have to see how this complex after treatment systems will survive and still be effective in 10+ year old cars.

 

They all use EGR; some sources mention that SCR reduces the amount needed though.
Some use both LNT and SCR. I believe BMW's in the US did.

When pollution controls first appeared on gas cars, they weren't as effective, nor as reliable as they are today. The technology for diesels is improving.

 

Under ideal conditions, fully warmed up at constant speed on a level freeway, there is no fuel consumption increase for the NOx emissions system. In this specific situation, it can in fact function as a passive system. This was documented in the ICCT sponsored West Virginia University study which triggered Dieselgate in the U.S.

Under very low load conditions, for example slow downtown traffic, diesel engines do not produce exhaust gasses hot enough to sustain sufficient temperature for the NOx catalyst. Various engine control measures are necessary to keep the NOx catalyst hot enough, similar to the Prius "flame thrower mode". This results in fuel consumption increases of up to around 5%, according to Bosch, in its recent publication about its newer more finely tuned system.

 

Yes, the technology itself is proven. What is still required is:
1. Manufacturers who equip cars with high quality, robust systems
and
2. Customers who are willing to pay for that.

Japan has already proven that Diesel cars are not necessary to reach the CO2 goals. But Diesel cars are necessary for German manufacturers to meet their profit goals.

 

Flame thrower mode. Yah-tah-hey.

 

Near as I can tell, the VW diesel cheat definitely hid poor efficiency that I understand SCR systems can fix. But having poisoned the well, USA passenger car diesels are rare and per announcements, getting even rarer. The good diesel vs bad diesel is more of an EU debate where Bosch announced they've figured out how to make low-pollution diesels without comment about efficiency effects.

I would observe there is at least one business, The Glider Kit Specialists | Fitzgerald Glider Kits, dedicated to building new truck bodies without diesel engines so rebuilt, highly polluting engines can be installed. In effect, never installing a modern SCR diesel emissions system much less a new Bosch-style diesel.

Of course this is moot as far as I'm concerned as we have two plug-in hybrids. They are EV around town and can go months, even a year, without getting a tank of gas. In contrast, our hybrids used to go +3 weeks between tanks and our last gasser barely went 2 weeks between fill-ups.

Bob Wilson

ps. Background

Source: Consumer Reports Tests VW Diesel Fuel Economy and Performance

In response to the scandal, Consumer Reports conducted new testing of 2015 and 2011 Volkswagen TDI diesel vehicles in this “cheat” mode to assess fuel economy and performance. We found a noticeable decline in fuel economy for both models. Our testing also showed reduced acceleration with the 2011 model, which is equipped with a lower-tech diesel filtration system.​

Source: http://www.autonews.com/article/20180425/OEM06/180429878/bosch-diesel-breakthrough

Thermal management

Bosch’s new process optimizes thermal management of exhaust temperatures, slashing nitrogen oxide emissions to one-tenth of the legally permitted limit, and doesn’t require new hardware, Denner said. The system keeps emissions stable even at cold temperatures, he said.​

 

There's a paper from Bosch that more fully describes the thermal management system for NOx control.


http://www.autonews.com/assets/pdf/bosch-nox-report.pdf

 

I mention BMW having a combo LNT and SCR system, and I now recall Cummins has the same on some engines. This might be the coming norm for diesels.

But let's take a step back. Diesels' fuel economy has dropped following stricter emissions. Yet, if we allowed gas cars to follow diesels old NOx limits, their fuel economy improve. Picture a Prius that could use lean burn. Cleaner exhaust comes with acceptable cost of reduced fuel economy. We've been living with tighter emission regulations on gas cars for far longer, so that cost is no longer thought of with them.

We might need diesels if we ever want to switch ICEs from fossil fuels to something renewable and sustainable.

The glider loophole was to be closed next year, but for reasons, won't be.

Bosch's work shows that diesel emission technology is improving. Unfortunately, when fuel is cheap, people aren't willing to pay the increased cost for a diesel or hybrid over the traditional gasoline car.

 

similarly, just like the engines and their maintenance, low sulfur diesel & biodiesel ain't cheap either.
.