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184 posts

Master Geek
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  Reply # 1950993 3-Feb-2018 05:18
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Aredwood:

Lastman:

The problem is NOX is a major factor in fine particle pollution deaths. The figure quoted seems to be about 5000 premature deaths in Europe per year, about half of all fine particle related deaths. And vehicles were the major contributor. Add to that the masive cost on healthcare of treating all the related disorders.

The effect on the environment isn’t quite as benign as you suggest, also.

The dieselgate vehicles only reduced NOX when they were being tested, otherwise they operated in more fuel efficient, less exhaust damaging modes. European laws were strict but the fine print allowed companies to certify vehicles that had high NOx emissions so diesels in Europe emitt high levels of NOx despite the regulations.


Lots of earlier diesel vehicles have EGR and other NOx reduction systems, but no particulate filters. How many extra deaths have been caused by those unnecessary particulate emissions? EGR systems have been fitted to diesel vehicles long before particulate filters have existed.


Also CO2 emissions cause deaths due to things like droughts and other natural disasters caused by climate change due to man made global warming. Heck, whole countries are predicted to disappear due to sea level rise.


Note also that alot of city based NOx emissions will also come from gas appliances. And what about NOx emissions from jet engines? They are not subject to any NOx emissions regulations.


Again, it is partly related to politics. As small disappearing island countries don't have much geopolitical clout.



So? That just reinforces the underlying fact that manufacturers have been unable to produce clean diesels. VW could get around European legislation but tried to cheat to get around the US rules.

NOx is poison, other particulates/gases, some of which are related to NOx are poison, or the other word for it in this context is air pollution. The point of the legislation was to limit pollution and so limit early deaths and sickness.

You can bring CO2 into it (the VW execs likely didn’t care about CO2 any more than they did NOx) but its not air pollution because its not poisonous and doing the sums on CO2 here might not be so simple anyway.

CO2 recduction is part of the wider issue of the direction of transportation and energy use.


7402 posts

Uber Geek
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  Reply # 1951020 3-Feb-2018 08:51
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Aredwood:

 

That above section backs up what I have said earlier. A whole host of problems, with the only benefit being NOx reductions.

 

As for commonrail diesel engines, main reason for using commonrail. Is it gives the ability to inject diesel at any time. For example, diesel is injected during the exhaust stroke to do a DPF "burnoff". But commonrail is both more complex, and my understanding is that the commonrail pump robs more engine power. Due to the need to constantly maintain very high fuel pressures. While the high injection pressures in distributor and unit injector systems are only produced while fuel is actively being injected.

 

Also have a read of the Talk section of the same Wikipedia page. There are alot of challenges to the claim about EGR increasing efficiency in petrol engines.

 

 

I agree about the whole host of problems associated with EGR, but fuel efficiency (until things get clogged up etc) isn't one of them.

 

It should be trivial to conduct a test on fuel efficiency on a petrol car with EGR enabled/disabled.  If many people are making that claim, then they need to back it up.

 

As for whether there's more power robbed by a CR pump vs mechanical injection, surely that's almost irrelevant?  I've owned two similar weight/size but different diesel vehicles, one mechanically injected, the other CR.  The CR produces about 50% more power over a much wider rev range, produces much much less pollution, and manages to do this while consistently using only about 60% as much fuel. (About 8.2 vs >14 l/100km around town).  Diesel vehicles are much cleaner than they used to be, but not clean enough when in some cities and countries a very high % of the private fleet is diesel.  That incentivised by very high taxes on petrol (which may be less locally polluting - but with higher CO2e footprint).


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Uber Geek
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  Reply # 1952240 6-Feb-2018 00:05
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Fred99:

 

I agree about the whole host of problems associated with EGR, but fuel efficiency (until things get clogged up etc) isn't one of them.

 

It should be trivial to conduct a test on fuel efficiency on a petrol car with EGR enabled/disabled.  If many people are making that claim, then they need to back it up.

 

As for whether there's more power robbed by a CR pump vs mechanical injection, surely that's almost irrelevant?  I've owned two similar weight/size but different diesel vehicles, one mechanically injected, the other CR.  The CR produces about 50% more power over a much wider rev range, produces much much less pollution, and manages to do this while consistently using only about 60% as much fuel. (About 8.2 vs >14 l/100km around town).  Diesel vehicles are much cleaner than they used to be, but not clean enough when in some cities and countries a very high % of the private fleet is diesel.  That incentivised by very high taxes on petrol (which may be less locally polluting - but with higher CO2e footprint).

 

 

 

 

Quote from the talk section:

 

 

EGR can definitely hurt efficiency. I performed very careful measurements with a 1995 Toyota Corolla (1.8L non-Calif. model) on a weekly commute, mostly highway, air conditioner off. After EGR was disconnected, highway mileage went from 34-35 mpg to a consistent 38-40mpg. This makes sense, since EGR reduces combustion temperatures and thus Carnot efficiency. It is interesting to note that the 1.6L version of this car is not equipped with EGR, except in California. This leads me to think that its effect is largely detrimental, and it's there mainly as an emissions band-aid. This is a vacuum-modulated EGR valve with an ECU-controlled VSV acting as an on/off switch.

 

 

Although EGR on petrol cars has alot of variables. It would be a bad idea disabling EGR on a Mitsubishi GDI engine. So test results for 1 petrol car model, would have very little relevance to other petrol cars.

 

While lots of other engines, had EGR fitted or not fitted, entirely up to the rules in force where the car was sold. California cars in the US were often made to different emissions standards as cars sold in other parts of the USA. While in NZ, the NZ new, Aussie new, and Japan new versions of the same car and same engine. Would often have different, or often no emissions controls at all in the case of the NZ new versions.






452 posts

Ultimate Geek
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  Reply # 1954609 10-Feb-2018 00:10
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kryptonjohn:

 

I would dearly love to delete the EGR on my VW but it means getting an P0401 insufficient flow error and nobody seems to be able to defeat that.

 

 

Mostly for the benefit of future readers who find this via an internet search, I would like to point out that any tampering, or removal of emissions control equipment such as EGR, is most likely illegal.

While not explicitly banned, the vehicle must still be able to pass the same test in place for entry of used vehicle's into NZ. It is likely that a vehicle with disabled EGR would produce excess NOx.

https://www.nzta.govt.nz/resources/rules/vehicle-exhaust-emissions-2007/

The revised Rule prohibits the removal of, or tampering with, emissions control technology on vehicles registered in New Zealand. Any vehicle with modified exhaust equipment must continue to be able to pass the same emissions test in place at entry for used vehicles. This measure is important as it makes it clear that it is not acceptable to remove or modify emissions control equipment on a vehicle in such a way as to make the emissions worse. It will also help enable new policies to be developed which will target the emissions of the in-service fleet.



MikeAqua:

 

kryptonjohn:

 

Doesn't matter now. Diesel is close to dead as far as new vehicles are concerned. Dieselgate and excessively restrictive emission controls have killed it. 

 

 

Diesels are still popular in the Ute and SUV categories which are the two biggest categories in NZ.  I'm not sure how that compares to other countries.

 

And then there are trucks and heavy machinery

 



There popularity is largely restricted to Large SUV's and Utes. Smaller suv's are most often petrol.

Much of diesel's popularity in this segment is due to our tax policies.

A petrol vehicle that is using 16l/100km to pull a trailer will be paying double the road tax of an identical vehicle with a diesel power-train.



Given the tainted image of diesel fuel in Europe (and how it was never great in the USA), it seems that automakers will be cutting back on R&D in this area. As an example, see the below article about toyota pulling out of that space.

https://www.ft.com/content/119239b6-9705-11e7-b83c-9588e51488a0

That said, it is likely diesel will remain around for a while as it is very popular for light vehicles in third world vehicles.

I think trucks and industrial vehicles will remain diesel for the near future. High hours of running, and larger engine sizes make for an easier business case for expensive emissions control hardware.




1471 posts

Uber Geek
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  Reply # 2066462 1-Aug-2018 17:34
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https://www.thenational.ae/business/technology/dieselgate-2-allegations-target-european-car-makers-1.753937

"The EC alleges motor manufacturers are manipulating emissions data again."

"European Union car makers may be submitting 'inflated' figures for their vehicles' carbon dioxide emissions to soften future targets for reducing the greenhouse gas, European Commission documents seen by AFP Wednesday show.

Authorities are currently switching over from an older emissions testing procedure known as NEDC to a new one called WLTP.

During the changeover, 'emission values officially declared by manufacturers may be inflated', Commission officials wrote to senior members of the European Parliament's environment committee and EU Council president Austria.

Declaring higher emissions values now 'would cause an increase of the 2021 WLTP targets ... the targets for 2025 and 2030 would also be weakened,' the officials explained.

Although the European car industry could well do without a new emissions outrage, the latest allegations differ from the 'dieselgate' scandal that has rocked the sector since 2015.

In that case, Volkswagen admitted to manipulating millions of cars to appear to emit less harmful nitrogen oxides (NOx) in lab tests than they were in real on-road driving.

Other manufacturers like Mercedes-Benz parent Daimler have since fallen under suspicion."

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