Diesels Aren't Bad

no doubt herr muller is putting some politicians in his pocket as we speak.

the work they have done over the years will be very profitable if he can convince the eu that the pollution standards are not correct. read: $$$$$$$$$$

what does toyota know? they know that they aren't german, so they'll look to squeezing the hydrogen dollars.

 

Implications in the linked article that diesel engines are fundamentally unable to meet European emission standards are nonsense. Light-duty diesel vehicles currently sold in the U.S., which have more strict NOx emission standards than Euro 6, are proof of that.

 

I don't see why it would be imposible to make diesel as clean as or cleaner than gasoline. We are talking about two very similar technologies.

One solution would be to put an oxygen separator on the car. I found one that would feed a 1.6L engine and small "enough" to fit on a small car, although it wouldn't have much trunk space afterwards. The separator consumes less than 1hp. Then cool the exhaust, which will now be mostly CO2 and H2O and feed that with the separated oxygen into the engine. The engine will now be running nitrogen free, and no nitrogen means no NOx.

With NOx out of the way the compression ratio can be raised and the timing advanced. The engine would be running on 70% EGR so that wouldn't be a problem. Or just make the engine out of ceramics and run straight oxygen and diesel. Again, no nitrogen, no NOx formation. And by using pure oxygen, or at least enriched oxygen, then the particulate, CO, HC and VOC emissions would be next to nothing.

 

Looks like we are all engineers here. ( yes, I'm being passive aggressive..I'm from Minnesota for crying out loud )

Seems to me that any tech they add to make the vehicles cleaner will in turn add complexity and weight. And possibly increase maintenance costs ( i.e. - urea injection ). These things increase costs in all areas ( purchase, operation, maintenance ) which in turn makes it harder to compete. Seems like a bit of a catch-22 to me.

BTW - @Isaac Zachary I see you are from Gunnison, CO. Visited the area last year. Loved it!

 

Was just reading 33% of the nitrogen pollution in Chesapeake Bay is from vehicles, and I have to guess that is diesel trucks.

 

The diesel cars are already as clean as many gas cars in the US. Some might match the Prius in emissions under 50k miles, but the manufacturs aren't willing to warranty them at them level at this time .Cleaner if you are looking at particulates. The equipment adds cost, and so does the use of DEF(urea) to operating costs.

Compared to emission control technology for gasoline, this technology is young. In another thread. Bosche announced they have greatly improved the effectiveness of current systems through more precise control of engine and emission equipment operations. So cleaner isn't going to be far off. Which might include lower cost.

 

I agree that the tech will get better. However, due to dieselgate, I think they have lost the perception battle...at least in the USA. It will take a long time to recover from that. Plus, the fact that electric vehicles are coming on strong puts diesels at even more of a disadvantage.

On the other hand, there probably will always be a small niche for them (in the USA). I'd say they are pretty much 'dead' for now though.

 

From what I understand they are attempting to ban diesels right now in Germany, and they want to ban them in most of Europe.

German court rules that cities can immediately ban older diesel cars - Autoblog

But it is ironic that people think gasoline is clean and diesel is dirty simply because a few companies cheated on their emissions. There isn't that much difference between the two types of fuel and how their engines work. This would be like saying that manual transmissions are destroying the planet, so buy an automatic becase they are so much better.

It's perfectly fine if they ban diesel, as long as gasoline is next on the list. It just doesn't make sense to ban diesel and put gasoline up on a pedestal as the "clean fuel" when it isn't.

If diesel is expected to get the same NOx and PM levels as gasoline, then gasoline should be required to get the same HC, CO and CO2 levels as diesel. And this needs to be enforced. Instead of fining VW and others and giving that money to the government, make them buy back their cheating vehicles from car owners or make those cars get the emissions they should without sacrificing fuel mileage or performance.

 

if people think diesels are more damaging environmentally and health wise, it is because science has let us down.
and also because of the smelly trucks and buses still on the road.

*i think they did make them buy back the cars. and in some places, add the more expensive emissions package.

 

Diesel might win out over hybrids in larger vehicles like minivans and the full size trucks and SUVs. The only hybrid van here is actually a plug in, and the previous attempt for big SUVs and trucks failed in the market.

In Europe, they have different standards for gasoline and diesel cars, and those only recently approached the limits of the US's tier 2 regulations.On top of that, diesel cars have been popular there for decades. Try picturing what the air would be like here if the majority of cars here were diesels with the emission controls of an '80s Mercedes diesel. In a way, GM saved us by making crap diesels back then.

While diesels can be made as clean as a gasoline car, it takes more effort and cost to do so.

I don't think other governments have been as harsh with VW as in the US.

 

but other governments have different agendas. politics overusing science is bad for most everybody.

 

The Continental electrically heated converter is a big step forward. When diesels idle, their exhaust can be too cool to work in the catalytic converter.

Bob Wilson

 

If those cars were all from the 80's that might be a good thing. That is, unless you're saying they have 80's emissions but are from years posterior to the 80's.

Back when diesel engines first came out they were by far much less polluting than their gasoline cousins, with the exception of particulate emissions. At some point it became easier to reduce the emissions on gasoline cars, but that happened in the mid 90's. If you take two cars from the 80's, one gas and the other diesel, the diesel would very certainly less than the gasoline car, with the exception of particulate matter. Even NOx emissions from an 80's diesel would likely be less than from an 80's gas engine. Not to mention that an 80's diesel doesn't have any emissions control devices (which weren't needed due to the lower emissions) but by now the EGR valve and catalytic converter on an 80's gasoline car are probably non-functional. So if you're going to drive a classic car with a classic engine, drive an old diesel. Otherwise you need modern day sequential port fuel injection, digital ignition timing, multiple sensors, a digitally controlled EGR system and a well designed threeway catalytic converter to beat the emissions on a diesel with a gasoline engine.

My 1972 VW Beetle produces way more pollutants than my 1985 VW Golf diesel. NOx, CO and HC are all way lower in the diesel.

 

I think there is a difference between banning all diesel cars vs. older diesel cars.

When legislation entices the owners to replace their older products, such as "polluting cars", or cooling equipment with "ozone-unfriendly refrigerants", or less-than-energy-efficient windows, washing machines etc., with newer/better ones, it can have a positive effect on the economy as well as ecology.

 

... and negative effect on a cars resale value

 

What's ironic about banning older diesel cars is that as you go back in model years, you come to a point where diesels are cleaner than gasoline cars for a respective model year with the exception of particulate matter. I'm not sure when exactly the change from diesels being cleaner to gasoline cars being cleaner came about, but I'd be willing to bet that if you took my 1985 diesel Golf and put it next to a 1985 gasoline Golf the diesel would likely get better NOx emissions and definitely get better CO and HC emissions. The only thing that older diesels fail at is PM emissions.

It would only make sense to ban older diesels if the only concern is PM emissions. But if its NOx, then both older diesels and older gasoline cars need to be banned since many older gasoline cars are going to be putting out a whole lot more NOx than the diesel cars. The trouble getting NOx levels down in diesel cars to what can be done in gasoline cars is a problem that mainly started in the late 90's. Now maybe banning diesel cars from the late 90's or early 2000's onward would be a logical solution to NOx emissions. But then we'd be banning newer diesels instead of older ones.

Really, the cars that should be banned are any and all that were designed to not meet the emission standard for their model year. And it shouldn't be the consumer's problem, they didn't design the vehicle. If the government mandated an emissions standard that was too low or too full of loopholes, they should be responsible for replacing the consumers' cars. But if it was a manufacture who didn't follow the emissions standard, they should be held responsible.

 

This is not true, in the 80s Golf diesel was not imported to the US just because it did not meet the NOx limits.

 

Europe may have had stricter NOx limits back then. Remember, lean burn in gas engines was once a regular practice, and many still were using carburetors.

 

What do you mean that the 80's diesel Golfs were not imported to the USA? They were imported and sold here in the United States along with the gasoline Golf's. I should know, I personally own one. And in it clearly states on my Golf and in the Golf's manuals that it was designed to met the US emissions standards for all passenger cars of it's model year.

Diesels originally got much better NOx emissions compared to gasoline engines back during the carburetor era, which is why emissions equipment, like EGR systems, was first put on gasoline cars, not diesel cars.

This brings up another point. If you have a gasoline car from the late 60's to late 80's it's likely that either the emissions equipment was taken off the vehicle or it no longer works. But there was no need for diesel engines to have emissions equipment back then because they met the emissions requirements without them. So if you have an old 70's or 80's diesel there's no chance that the emissions equipment has failed. Add to that the difficulty to find working emissions equipment for those model years on gasoline engines. When I rebuilt a 1974 VW dual heat riser engine I was unable to find a working EGR valve, even after paying quite a bit of money for supposedly working ones, and so ended up just putting it together without it. What a shame.

When the lean burn engine came out, just like the diesel engine, it too got stellar NOx emissions for it's time. Much better than your average gasoline engine. I have a book on fuel and emissions from 1975 somewhere here with graphs that compare emissions between different engines back then and the Honda lean burn engines produced a mere fraction of the NOx emissions that the other gasoline engines produced.

The thing is that carbureted and throttle body injected gasoline engines aren't able to distribute their fuel very well. This leaves a lot of lean pockets in each cylinder and even lean cylinders that are very close to or right at the point of peak NOx production. Diesel and lean burn engines run much leaner, which creates fewer pockets that are close to the peak NOx production point. (As you get leaner and leaner you end up producing less and less NOx. A case in point are some propane engines that run at extremely lean air/fuel ratios and don't produce any noticeable amount of NOx as a result.) This is why diesel and lean burn engines used to beat typical gasoline at producing fewer harmful emissions hands down.

As gasoline technology progressed it has become possible to thoroughly mix gasoline into the air with hardly any lean pockets and nearly zero difference between cylinders. This greatly reduces NOx production, but doesn't eliminate it. However, even more important is that since gasoline engines run at stoichiometric air fuel ratios it is much easier to reduce NOx via a catalyst in the exhaust, making them easier to produce better emissions than diesel engines. But this has only been the case since port fuel injection and catalytic converters have been the norm. Diesels used to get better emissions even without any emissions equipment.

It's only been in recent times that diesel emissions have been much more difficult to make reach the same levels attainable in gasoline engines. But that doesn't mean they were dirtier from the beginning.