So what do we think of diesels now?

[Curlytips]

HM government is now suggesting we "think carefully" before buying a diesel car, and already London will introduce emission charges on top of congestion charges. So could the future mean increased tax on diesel fuels in future?

And what does that mean for aviation? Do those new diesel-powered aviation engines look less attractive (and are they worse than our 100LL polluters)?

Should any of us, Avgas or Jet A1 users, feel guilty when probably every bus in the capital is diesel powered (even though some are bio-fuel)? And here's my real question for the team.......

When jet aircraft (airliners, air force or whatever), are turning and burning, are they contaminating the atmosphere with nitrous oxide or anything, and does it fall to the surface to join in with our city pollution levels?

[Philoctetes]

And shipping? - virtually burning tar - ie fuel that has to be preheated before it can be injected into cylinders.

But that must be exempt as they transport materials needed for car battery construction from one side of the world to he other!

[piperboy84]

Should any of us, Avgas or Jet A1 users, feel guilty when probably every bus in the capital is diesel powered

I'm was burdened with feelings of guilt knowing my 6 cylinder, 3 liter Land Rover Discovery engine was being choked of fresh oxygen with all that exhaust return CSV valve emmission shyte the factory put on it . Bypassing it allowed both myself and the Landy to breath easier.

[BEagle]

Diesel? DIESEL??

Simply NOT an Officer's fuel, old boy...:=

DEATH BEFORE DISEASEL!!

[abgd]

The main reasons to burn Avtur IMO is a reduced risk of immolation in an accident + reduced greenhouse emissions. The main environmental reason not to burn 100 leaded is that it's toxic enough that I don't like splashing it on myself. Despite the recent diesel scandal these reasons still stand and I'd opt for a heavy fuel aircraft engine if they were affordable.

FWIW I believe diesel buses and lorries are meant to have less particulate and NO2 emissions than most diesel cars.

Airliners do emit similar nasties, but at least spread them equitably about over the highlands and Atlantic ocean rather than just London and similarly built up areas, which makes it somewhat less harmful.

[abgd]

But that must be exempt as they transport materials needed for car battery construction from one side of the world to he other! They transport petrol from one side of the world to the other in much the same way. The difference is they need to do so every time you need a tankful whereas batteries can be recharged. It's easier to recycle batteries than petrol too!

[Avitor]

An electric car? No thanks.

[onetrack]

Here in my city Down Under, we burn CNG in most of the 1300-strong bus fleet. Not only because it is much cleaner, but because we also have oodles of it under Australia and our coastal waters (Australia has the 2nd largest supply of NG in the world, behind Qatar as No. 1).

As to diesels, they are a dying engine type. Just looked at a new Isuzu D-Max, they now have a particulate filter in the exhaust, that needs to be run through a "burn-off" phase - every 500km!

Diesels were once famous for simplicity, long life, high torque, and economy.
With every "advance" in newer diesel engines, fuel economy worsens, complexity increases to petrol engine levels, and the sheer costliness of maintenance and repair on them makes your eyes water.

It's highly unlikely that diesel will ever be removed as a power source from the heavy industrial power side of things (heavy trucks, earthmovers, ships) - but diesel power in small road vehicles has always been an "iffy" equation - particularly where the average urban dweller only travels a few kms or a few miles in each trip.

Aircraft diesels have only ever been a "flash in the pan" and they will never amount to anything. The weight required for diesel engine strength will always work against them.
I personally believe the future will see more hybrid engines, and a rapid increase in electric motive power.

One only has to look at the advances in electronics and electrical design in the last 30-40 years to see that electrical design still has great potential for efficiency and weight-saving, as compared to liquid fuels that are near the peak of their design.

Who recalls when computers were the size of a room and could only handle basic calculations, and only then by highly trained operators utilising special computer language?
Yet today, we carry in our pockets and purses, mini-computers that connect us to the entire world in seconds, that provide detailed maps, and which provide video, photo-and movie-taking, all in the one little hand-held device. The old computer designers and electrical engineers of the 60's and 70's would be amazed at the speed and breadth of electrical and electronic development of today - as we will be, with new major advances in electrical power technology in the next 20 years.

[Mechta]

It's highly unlikely that diesel will ever be removed as a power source from the heavy industrial power side of things (heavy trucks, earthmovers, ships)

Just imagine if a clean fuel for oceangoing ships could be found? No, that'll never happen...

http://www.rk-marine-kiel.de/images/content/infos/maritimes/windjammer/reederei_laeisz/preussen.jpg

[Katamarino]

The main reasons to burn Avtur IMO is a reduced risk of immolation in an accident + reduced greenhouse emissions.

That might be true in the tame parts of the world, i.e. (parts of) Europe and North America, but if you want to fly anywhere more interesting then fuel availability means that an aero-diesel is a no-brainer. The SMA first generation one has a couple of annoying flaws, and we all know about the issues with Thielert, but more modern engines are looking pretty good.

[Mariner9]

To answer the OP, 'diesel' GA aircraft run on Jet A-1 (i.e. kero), not diesel. Jet A-1 specs are not yet changing to address environmental concerns, but its only a matter of time.

As for shipping, fuel environmental specs have been tightening for years and are continuing to do so. Google "Marpol Annex VI" and "ISO8217" if you want more information.

[27/09]

One only has to look at the advances in electronics and electrical design in the last 30-40 years to see that electrical design still has great potential for efficiency and weight-saving, as compared to liquid fuels that are near the peak of their design

There has certainly been some amazing advances. One of the most significant being the reduction in the amount of energy needed to power those devices.

Unfortunately physics dictates how much energy an aircraft needs for it to fly. Reducing energy consumption like they have for computers isn't an option.

The answer lies in developing the best (cleanest, safest, highest energy for volume/weight) fuel. The fossil fuels are hard to beat right now. Battery technology isn't exactly environmentally friendly either.

It's my guess the future will be batteries or fuel cells once they can store 12 to 14 hours of energy for a 787 size aircraft.

[Jan Olieslagers]

'diesel' GA aircraft run on Jet A-1 (i.e. kero), not diesel
Some can, the Thielert at least and I think the Wilksch too (if that is still around, which I doubt). In fact I can't see why ANY kerosene engine could not also run on diesel fuel, which is only slightly "thicker" making it a better lubricant.
There have even been reports of recreational fliers running their diesel on "red" heating fuel oil - identical to road diesel but for the colour.

[Sam Rutherford]

The SMA in our C182 was great (with some limitations) but clearly the plan was then dropped by Cessna.

I run an extremely ugly but extremely cheap Fluence EV (100% electric) which is interesting with both positives and negatives...

Battery capacity/size/weight is the key issue - once this is sufficiently advanced things will change very quickly...

[chevvron]

HM government is now suggesting we "think carefully" before buying a diesel car, and already London will introduce emission charges on top of congestion charges. So could the future mean increased tax on diesel fuels in future?


The Mayor conveniently forgets the proliferation of wood burning stoves which seems to be in fashion. These are just as polluting as diesel cars as the fuel isn't refined in any way, unlike the various grades of 'smokeless' coal produced in the aftermath of the smogs of the '50s.

[ericferret]

Man takes diesel car in for MOT test having recently filled it with Jet A and forgotten about the emissions test. Realised his error, but too late to back out.
Tester "the figures on this are really low never seen one this good before"

True story

[ChickenHouse]

With current discussion after VW-Dieselgate we do not need to discuss facts, physics or chemistry, decision will be taken on ideologic and political abstraction layer. Even further with all that biological waste put into diesel I fear to put that solylent green into an aircraft. Yes I do drive a diesel car, but I try to feed it on biological free diesel, avoiding what is called Dieselpest. Jet-A is not diesel, but quite close, so I believe our politicians are completely unable to tell the difference. As big as I would like to see a more environmental approach for aviation fuel, I do not see what the alternative is, yet.

[DirtyProp]

I want one of these:

Steam Car Club Dobles (http://www.steamcar.net/dobles.html)

But with a slightly more modern body, chassis, brakes, suspensions, etc.

[ChickenHouse]

@DP: YMMD, thx! But why a modern body, the old ones are just fine. These cars are from an era after Siemens found out that electric street transportation is not such a good idea - what he was convinced of in the beginning of 1881. The reasons why he abandoned are still valid.

[A and C]

Light aviation contributions to pollution are so small as to be insignificant, I did see figures that suggested that the annual U.K. GA fuel burn was equal to the fuel burn for an hour on the M25 at rush hour.

I don't know the sorce of these numbers but I think it sums up the scale quite well.

[ChickenHouse]

Light aviation contributions to pollution are so small as to be insignificant, I did see figures that suggested that the annual U.K. GA fuel burn was equal to the fuel burn for an hour on the M25 at rush hour.

I don't know the sorce of these numbers but I think it sums up the scale quite well.
Did facts ever keep politicians away from stupid decisions?

I just read in a German newspaper they plan to ban Diesel powered cars from Stuttgart if they do not comply with Euro 6 regulations - their contribution to pollution in that town was estimated to be less 5% ... It is all about ideologies, not reality. I will be allowed to burn 100LL on top of their heads, but can not take the 2 year old car of my friend there to drive into town?

[The_Pink_Panther]

Alright, I'll continue the thread drift; can someone fill me in on how diesel cars are so bad that cities are looking at measures to ban them?
Diesel CO emissions are half of petrol, diesel particulates (the sooty stuff?) is the same, but their NOx levels are slightly higher.
I believe the NOx / CO difference is down to the difference in the chemistry of petrol / diesel burn, but I'm open to being educated.

[ChickenHouse]

Alright, I'll continue the thread drift; can someone fill me in on how diesel cars are so bad that cities are looking at measures to ban them?
Diesel CO emissions are half of petrol, diesel particulates (the sooty stuff?) is the same, but their NOx levels are slightly higher.
I believe the NOx / CO difference is down to the difference in the chemistry of petrol / diesel burn, but I'm open to being educated.
First, it is a political and ideologic hunt, not a facts driven one.

Second, NOx is that tad higher that Diesel qualifies as "we make the world better" pretend-carrier.

Third, a problem is soot. As long as we had the old Diesel engines, soot was only a problem for the mom with her clotheline very close to the streets, but - every dumb idiot was able to see the black stuff. Then they invented the Diesel cat, the visible soot disappeared, but the physics got a lot worse as Diesels now produced tiny and airborne particles instead of the black rocks collected at the curbstone. They invented a bigger problem by solving a visible unseemliness. Then somebody even found out that tiny particles could have a medical impact and boom, next wave. Had they left it at the old soot throwers, we would not face the problem.

[Basil]

Theresa May pledges to protect diesel drivers | Daily Mail Online (http://www.dailymail.co.uk/news/article-4380752/Theresa-ll-protect-diesel-drivers.html)
A scientific adviser, who has now admitted that he was wrong, was driven by an obsession with carbon emissions.
Can we really believe any of those characters? Do they first come up with a conclusion and then go about 'proving' it?
Glad to see that the PM is, at least, talking the talk; we shall see if she puts rhetoric into practice and stands up to money grabbing city councils.

[m.Berger]

Southampton has spent years solidifying the traffic in order to justify a congestion charge. I shall be keeping my twenty year old Diesel. It will cost the planet much more to melt it down and replace it than it will ever pollute.

[arra_halc]

Light aviation contributions to pollution are so small as to be insignificant, I did see figures that suggested that the annual U.K. GA fuel burn was equal to the fuel burn for an hour on the M25 at rush hour.

I don't know the sorce of these numbers but I think it sums up the scale quite well.

The stat I saw was that the total fuel that evaporates from Car fuel tanks via the breathers exceeds total consumption of 100LL across the whole of Europe.

[The Ancient Geek]

100LL is widely available in Europe and the USA but in most of Africa it is virtually unobtainable, making GA impossible without having 200 litre drums trucked in to any airfield that you plan to visit in advance and at great expense.
Diesel engines for light aircraft are the only way forward in these areas and they are becoming increasingly popular.

[Curlytips]

Received new format AOPA members magazine at weekend. Looks a nice "face-lift" to mag and includes an article talking about Warter being the only producer of UL91? I thought there were other players .....Total, Air BP etc but notice less and less airfields stocking, and no longer any price advantage. But a question I never really got the answer to, is whether by running my O-360 on UL91, do I get any less power output? Without any price difference is there any remaining advantage with the exception of being green?

What does the team think?

[Johnm]

Most of these policies are driven by green campaigners, many of whom make snake oil salesmen look respectable. The difficulty is that quite often they demand that something be banned e.g. Lead in petrol. However they don't then follow through and consider whether the solution (carcinogenic additives and CAT full of toxic heavy metals) might be worse than the problem.

[mikemmb]

I want one of these:

Steam Car Club Dobles (http://www.steamcar.net/dobles.html)

But with a slightly more modern body, chassis, brakes, suspensions, etc.

Steam cars ? nourishing obscurity (http://www.nourishingobscurity.com/2011/10/steam-cars/)

DP.......try the Pelland for size!

[onetrack]

The stat I saw was that the total fuel that evaporates from Car fuel tanks via the breathers exceeds total consumption of 100LL across the whole of Europe.This statement is completely incorrect, as petrol-powered vehicles have had totally-enclosed fuel systems since the early 1970's to prevent excessive fuel evaporation losses.

The system is called Evaporative Vapour Emission Control (EVAP) and is one of the earliest emission control systems fitted to petrol-powered vehicles.

The primary vapour control device is a charcoal-filled canister that is fitted either in the engine bay, or close to the fuel tank.

Howstuffworks.com - Evaporative Emission Control System (http://auto.howstuffworks.com/evaporative-emission-control-system1.htm)

[jolihokistix]

The air in Putney high street is among the most polluted in London. Despite the introduction of hybrid buses, the mayor has taken to rerouting them to avoid the worst spots. There are calls to scrap all of London's diesel buses, but what would you do with all of them?

[Steve6443]

Did facts ever keep politicians away from stupid decisions?

I just read in a German newspaper they plan to ban Diesel powered cars from Stuttgart if they do not comply with Euro 6 regulations - their contribution to pollution in that town was estimated to be less 5% ... It is all about ideologies, not reality. I will be allowed to burn 100LL on top of their heads, but can not take the 2 year old car of my friend there to drive into town?

Consider their choices. By (European) law they HAVE to do something to reduce the emissions. So what can they do? Ban ALL diesel cars? No, because there would be an outcry. However by targeting a selection of vehicles and claiming these are dirty, this allows the Greens to claim the moral high ground without a blanket ban on all diesel cars, ensuring that sufficient vehicles have been eliminated from the city in order to clean up the air.

Personally speaking (and that's only cos I drive an EU6 car) I'd prefer that approach than that favoured by our favourite deluded hypocrite Khan, saying he's going to charge 24 quid a day for diesels to enter his Londonistan, irrespective of emissions. As if a tax ever helped the environment......

What I find interesting is that your friend's two year old car doesn't meet the limits for the EU6 regulations, but my 3 year old car does......

[Basil]

The air in Putney high street is among the most polluted in London. Despite the introduction of hybrid buses, the mayor has taken to rerouting them to avoid the worst spots. There are calls to scrap all of London's diesel buses, but what would you do with all of them?
Because it's usually at a standstill!
Must be bad to reach all the way to Japan ;)

[ShyTorque]

Removing HGVs from roads would help. Unfortunately, petrol engines aren't really an option for heavier vehicles.

[jolihokistix]

Tokyo has been working on this for 20 years at least:
Tokyo Metropolitan Government's Efforts to Control Diesel Vehicle Emissions | Japan for Sustainability (http://www.japanfs.org/en/news/archives/news_id030817.html)

[Capt Kremmen]

Theresa May pledges to protect diesel drivers | Daily Mail Online (http://www.dailymail.co.uk/news/article-4380752/Theresa-ll-protect-diesel-drivers.html)
A scientific adviser, who has now admitted that he was wrong, was driven by an obsession with carbon emissions.
Can we really believe any of those characters? Do they first come up with a conclusion and then go about 'proving' it?
Glad to see that the PM is, at least, talking the talk; we shall see if she puts rhetoric into practice and stands up to money grabbing city councils.





The 'scientific adviser' who was wrong, is a long time proponent, adviser and activist on climate change !

[onetrack]

The air in Putney high street is among the most polluted in London. Despite the introduction of hybrid buses, the mayor has taken to rerouting them to avoid the worst spots. There are calls to scrap all of London's diesel buses, but what would you do with all of them?You convert them to run on CNG, the same as we have done in Australia. It is an economic move, it just requires initial capital outlay - but the benefits are there in greatly reduced emissions and a reduced fuel bill.

[soay]

The 'scientific adviser' who was wrong, is a long time proponent, adviser and activist on climate change !
The thing is, when he gave that advice, the evidence was in that climate change was going to globally destabilise the climate if we didn't our reduce greenhouse gas emissions, but not so obvious that the emissions from diesel engines would be locally so bad for health. That's what scientists do: go where the evidence takes them.

Incidentally, global warming induced changes, such as the meandering jetstream (https://www.theguardian.com/environment/2016/dec/19/arctic-ice-melt-already-affecting-weather-patterns-where-you-live-right-now), and increased water vapour in the atmosphere, are not going to improve flying conditions for GA.

[mm_flynn]

... but not so obvious that the emissions from diesel engines would be locally so bad for health. ...

I think that is a difficult to sustain position. The impact of diesel pollution and the challenges of making abatement equipment that worked for start/stop local journeys has been well understood for a long time.

There is a common view that the risks of climate change are of such an existential nature that it is worth taking significant pain now (local pollution, forgone development, lower material output, etc, - but not the use of nuclear power) to attempt to reduce the longer term impact. I suspect it was this conscious trade-off that drove the recommendations.

[soay]

Well, in retrospect, the diesel engine manufacturers over promised and under delivered, while the regulation agencies looked the other way. In fact, most of the governmental responses to the problems of human induced climate change - which as signatories to the Paris accord they have acknowledged is a real threat - have been ineffectual, as evidenced by the ever increasing percentage of CO2 in the atmosphere (https://climate.nasa.gov/climate_resources/24/). The average is approaching 410 ppm, compared with about 310 ppm when measurements were started at the Mauna Loa Observatory in Hawaii in 1950. This is higher than at any time in the past 400,000 years, so it's unsurprising that we've just had the two warmest years on record (https://www.nasa.gov/press-release/nasa-noaa-data-show-2016-warmest-year-on-record-globally), globally, and record low sea ice extent at both poles (https://www.nasa.gov/feature/goddard/2017/sea-ice-extent-sinks-to-record-lows-at-both-poles).

In aviation terms, higher temperatures are manifested as more water vapour and energy in the atmosphere, which rarely improves flying conditions (https://link.springer.com/article/10.1007/s00376-017-6268-2).

[m.Berger]

And what instruments were they using to measure the PPM 400,000 years ago?
Sounds like poppycock to me that cannot be demonstrated nor proven, only asserted.

[abgd]

How about drilling a column of ice from antarctica then extracting air from bubbles and measuring it? There are more abstract ways such as looking at stomatae on fossil plants, which are unlikely to be as reliable but can be used to corroborate findings.

[Maoraigh1]

Does Mauna Loa produce CO2, which many volcanoes do? If so, why quote measurements from it?
Why would moving coal burning manufacturing processes to another part of the planet, (China) be expected to affect global warming?
I'm just mistrustful

[abgd]

Does Mauna Loa produce CO2, which many volcanoes do? If so, why quote measurements from it?
...
I'm just mistrustful

It's a good question, for which you could find the answer with 2 minutes of googling if you were genuinely interested.

https://earthobservatory.nasa.gov/blogs/climateqa/mauna-loa-co2-record/

[horizon flyer]

Not a good idea to run a diesel car on Avtur it will wreck the fuel pumps as provides no lubrication for them. In all aero diesels, the fuel pumps have external lubrication from the engine oil by design.

What is needed is a low rev max 2700rpm, direct drive, with good power to weight ratio so the best way is a 2 stroke 3 cylinder or greater design. this means overlapping power strokes lower peak torque 1 power stroke/cyl/rev lower torque ripple and no torque reversal (prop driving the engine) plus lower revs needed for given power output.

All the 4 stroke designs have problems in several of these areas, so I don't think any of them are the long term solution.

One of the best would be the 8 cyl 2 row radial 2 stroke by Zoche been in development for over 20 years. Have seen the mock up at an airshow, very compact but I think it is now just an EU grants scam and will never see the light of day.

The hope is for the Delta Hawk V4 to replace the unreliable Lycoming IO360 as it works very well in the Cirrus SR20 they plan to have it certified in the next year.

There are other uniflow designs, single piston per cyl and 2 piston per cyl with both single and dual crankshaft models. The problem is engine development even with all this computer added design/manufacturing seems to cost a fortune and take for ever.

[soay]

Why would moving coal burning manufacturing processes to another part of the planet, (China) be expected to affect global warming?Where on Earth did you get that idea from? The only thing that effects is our ability to ask what's the point of reducing our CO2 emissions when they are relatively small compared to China? That's because we've offshored our manufacturing there, so the Chinese are emitting CO2 on our (UK, USA, Europe) behalf.

[LowNSlow]

abgd: all the ice core samples demonstrated that temperature increase preceded CO2 increase..... Ooooh hockey stick.
Follow the money......

Back on track:

Diesel engines: trains, trucks and tractors.

The cr@p that ships burn isn't even close

Jet A1 in cars, bad move, jet fuel doesn't have to lubricate fuel pumps which is why it's lubriscity is much lower. Cue problems making ex-car diesel engines run on Jet-A1.

[abgd]

all the ice core samples demonstrated that temperature increase preceded CO2 increase..... Ooooh hockey stick.No, not all of them - specifically the most recent one. As I understand it the argument goes that increased temperatures increase CO2 and Methane emissions which in turn increase temperatures, so there's a positive feedback loop which amplifies temperature fluctuations due to natural minor 'insults' such as changes in the Earth's orbit that would otherwise cause only small changes in temperature:

https://www.newscientist.com/article/dn11659-climate-myths-ice-cores-show-co2-increases-lag-behind-temperature-rises-disproving-the-link-to-global-warming/

I'd agree it's not quite such a straightforward story as 'CO2 rises, then temperature rises after'. But straightforward stories only take you to O-levels/GCSE level.

The problem with climate science is that it's thoroughly messy. For example, the following article supports the idea that CO2 and Methane cause climate change:

http://www.nature.com/articles/srep21691

I think I could understand this at a low level if I had a few months to devote to it and access to scientific journals again. If you gave me a few years I could get to a point where I could hold and defend an opinion on whether it's good science or bunkum or something in between. I'd have some idea about where the weaknesses in the arguments lie and which questions are more-or-less settled.

I have a background in biomedical science which is similarly messy. I have a shallow understanding of some of the mathematical techniques used. But the truth of the matter is, I'm not a specialist in the field and something tells me that you're not either.

Will power grids be able to cope with intermittent renewable supplies? Are most refugees genuine, and do they pose any risk to us? Is the NHS collapsing because of underfunding, lazy doctors, the ageing population or deliberate mismanagement with a view to privatisation? How bad are diesel fumes for our health? Will Brexit be good or bad for the economy? Should we all be taking statins?

None of us are likely to be experts on more than one of these issues, if any. And yet if we wish to be citizens partaking in public discourse we need to hold opinions about the issues that seem important to us, and what to do about them. So how do we decide whom to trust as advisers?

[soay]

all the ice core samples demonstrated that temperature increase preceded CO2 increase
That's like saying that people died of cancer before tobacco was smoked, so smoking can't cause cancer. It's a logical fallacy.

Natural processes buried megatons of carbon, in the form of coal, oil and methane, which we are burning and releasing their products of combustion into the atmosphere. This is why the current CO2 increase is triggering the temperature increase, rather than following the natural pattern. Of course, once temperatures get high enough, positive feedbacks will kick in, naturally releasing greenhouse gases stored in currently frozen methane clathrates. That's when we will lose all ability to prevent runaway temperature increases. Observations indicate that this process may have already begun.

[andytug]

Will power grids be able to cope with intermittent renewable supplies? Are most refugees genuine, and do they pose any risk to us? Is the NHS collapsing because of underfunding, lazy doctors, the ageing population or deliberate mismanagement with a view to privatisation? How bad are diesel fumes for our health? Will Brexit be good or bad for the economy? Should we all be taking statins?

None of us are likely to be experts on more than one of these issues, if any. And yet if we wish to be citizens partaking in public discourse we need to hold opinions about the issues that seem important to us, and what to do about them. So how do we decide whom to trust as advisers?

You would need to find those without a vested interest, nor funded by any private company or government department with an agenda.
Problem is I suspect those kind of scientists no longer exist.

[soay]

You would need to find those without a vested interest, nor funded by any private company or government department with an agenda.
Problem is I suspect those kind of scientists no longer exist.
With all the fake news about these days, it's easy to become distrustful of everyone, but bear in mind the relative scale of the agendas. The only possible one that scientists from all over the world researching climate change could have in common would be keeping on some notional gravy train. Compare that with the implications for the fossil fuel corporations if we all have to stop burning their fuels. It's an existential crisis to them, so they have responded with a propaganda campaign to sow seeds of doubt on the science and the scientists who are threatening their livelihood, using the tactics so successfully employed by the tobacco corporations. ExxonMobil, for example, employ scientists who warned them in the 1970s that burning fossil fuels would cause global warming (https://www.scientificamerican.com/article/exxon-knew-about-climate-change-almost-40-years-ago/). Since then, they have spent more than $30 million on think tanks that promote climate change denial. Ask yourself which agenda is most likely.

[abgd]

You would need to find those without a vested interest, nor funded by any private company or government department with an agenda.
Problem is I suspect those kind of scientists no longer exist. So do you give up on all scientific knowledge?

It seems to me that most corporate and government interests are not sympathetic to the idea of man-made climate change and the need to do something about it. At least, this has not historically been the case. Sure, there will always be people (e.g. wind-turbine manufacturers and solar panel manufacturers) who will benefit from action on climate change, but as Soay points out, my feeling is that their political and economic power has historically been far less than that of the oil companies. US and Canadian administrations in particular have been actively hostile to climatologists, even removing publicly funded data from the public domain on occasion: book burning for the 21st century.

https://www.wired.com/2017/01/rogue-scientists-race-save-climate-data-trump/

It seems to me that scientists who state that they believe in global warming are acting strongly against their own interests, so if anything I feel this strengthens their claims.

That leaves accusations of groupthink. Having been a scientist, my own bias and sympathies are towards scientists. A good scientist really is a truth-seeker. Sure, you want to win the respect of your peers with decisive and well executed experiments - but you are also well aware that you could lose your reputation if your claims turn out to be untrue. In my own field of psychology there have been bad eggs who've falsified results. But that field tends to be the preserve of small groups working on research that is never replicated. Climate change science is more likely to involve big groups of people - think how many people are involved in launching a satellite or drilling an ice core and how hard it would be to conspire to manipulate a result. The science is replicated and contested. Errors are uncovered and corrected. To me, it seems likely to be good science, with the caveat that the error bars are always going to be big because it's inherently a messy field to work in.

[Basil]

The much touted 40,000 deaths pa is 'notional deaths'. People aren't ACTUALLY dying.
They work out that people MAY die a month earlier, multiply that by the number of actual deaths and come up with this imaginary figure.
e.g.: England & Wales 530k deaths pa x 1/12 = 44k

People are ACTUALLY living longer now.

This Diesel thing is just another Project Fear.

[mm_flynn]

The much touted 40,000 deaths pa is 'notional deaths'. People aren't ACTUALLY dying.
They work out that people MAY die a month earlier, multiply that by the number of actual deaths and come up with this imaginary figure.
e.g.: England & Wales 530k deaths pa x 1/12 = 44k

People are ACTUALLY living longer now.
That actually isn't how they do it. They look for correlations in death rates vs exposure to various factors (such as high levels of particulates). This is how 'deaths from' indirect or cumulative causes are worked out. This would include factors such as particulate pollution like diesel, water pollution, cigarette smoking, radiation exposure, lifestyle choices, genetic variances, etc.

The fact that people are living longer only says the benefit of various favorable factor changes and generally increasing health spending is more than offsetting negative factor changes.

Diesel particulate is as much project fear as was addressing sewage in drinking water and the coal driven London Smogs of the past.

[Silvaire1]

What do I think of diesels? The same as I've always thought of diesels: the unrefined fuel stinks and doesn't evaporate, the particulate smoke stinks and blows directly in your face when you're walking or riding a motorcycle (even with the newest technologies), they make urban buildings black, they are over complex and expensive to maintain (particularly for aircraft) and their existence on the road is the result of a European regulatory and tax regime that disingenuously forces people to drive them for the sake of energy security that would be better achieved by other means. And they are built by liars. I've driven them both old and new, disliked them from inside and particularly outside, and will never own one. Exactly the same opinion I had of them 10 years ago.

In my experience the very worst thing about European roads is Diesel engines: they are western Europe's 21st century version of the 20th century East Block two stroke. It's an honest relief when I can escape Diesel engines to roads where they aren't so prevalent. I hope that with the aimless political wind now by luck blowing against them they'll be gone in due course, sooner rather than later.

[Parson]

Well I was going to buy a Golf GTD but I'm now looking at a GTI.

Did fly a converted C172 diesel a few years back. Was so nose heavy, wasn't able to trim enough nose up on approach - dangerous.

[ZFT]

Just bought 3.6 turbo deisel. Why? Deisel is 25% cheaper than petrol where I reside. Simple economics and I have no faith or trust in any of these reports anyway.

[Elephant and Castle]

I despair when I see a group of people who on the face of it should be intelligent spout such strong opinions on things they know next to nothing. How are we ever going to make any progress or fix our problems if any solutions are immediately dismissed as lies by people who not only know very little but also lack the intellectual curiosity to follow the scientific method to back their claims.

[S-Works]

I love my diesels. My car is a new Cayenne S Diesel and is smooth powerful and a delight to drive with massive torque all delivered low down. My Motorhome is Diesel, my wife's car is diesel, my Landrover is Diesel.

They will pry my Diesel engines from my cold dead fingers........ :)

[Kerosene Kraut]

In aviation diesel is still perfect as it can run on kerosene that is cheap and available everywhere. Avgas has become exotic in many parts of the world including the military's.
However I'm still not sure if the perfect aviation diesel engine already exists? Not sure about modified car engines. My choice would be nothing that needs battery power to keep going.

For private car use I see diesel engines dying. They have been used for the wrong concept: Instead of making them maximum efficient (that would have been the logical choice) they went the maximum vehicle size plus maximum horsepower/torque route. Not being as clean as advertised will kill them now. You can see the sales numbers erode already.

[lederhosen]

I fly a 172 with a CD155 engine in a large group. It is a well equiped aircraft and was expensive to acquire, so the hourly costs are not cheap. It is quite heavy and performance low down is nothing special. It requires lengthy warm up and cool down periods. Power setting is done by setting a percentage, so you have to look down and consciously check it. This takes a bit of getting used to as the throttle movement makes setting exact percentages not very intuitive. We run it on car diesel, which is a lot cheaper and with the lower fuel burn the fuel cost to the group is much lower.

[Kulwin Park]

I fly a 172 with a CD155 engine in a large group. It is a well equiped aircraft and was expensive to acquire, so the hourly costs are not cheap. It is quite heavy and performance low down is nothing special. It requires lengthy warm up and cool down periods. Power setting is done by setting a percentage, so you have to look down and consciously check it. This takes a bit of getting used to as the throttle movement makes setting exact percentages not very intuitive. We run it on car diesel, which is a lot cheaper and with the lower fuel burn the fuel cost to the group is much lower.

Great post! Very informative of the highs and lows of the CD155

[Mechta]

However I'm still not sure if the perfect aviation diesel engine already exists? Not sure about modified car engines. My choice would be nothing that needs battery power to keep going. That narrows the field to anything with a mechanical injection pump. The Weslake Dieselair engine in its original form (as flown in a Luscombe Silvaire) and the French Gazaile which used the Peugeot/Citroen 1.4 from the 106/Saxo, both qualify.

http://gazaile2.free.fr/img/imgFini/moteur/diesel.jpg

https://translate.google.co.uk/translate?hl=en&sl=fr&u=http://gazaile2.free.fr/&prev=search

The downside of mechanical injection is reduced efficiency (compared to common rail diesels) and lower power to weight ratio.

[Jan Olieslagers]

That's reducing the facts to the essential, @Mechta, thanks!

Now I agree that it is desirable, at the very least, to have the engine(s) operative without any dependency on the aircraft electrical system. Still, every petrol engine requires sparks so some kind of electricity is required; yet some meet this requirement. The Rotax 912 family at least, and I think a good many US engines too, those that run from magneto's. Thinking along the lines of the 912, why couldn't a fadec get electrical power from a completely separate circuit, with its own generator coils? Does it require a lot of power, perhaps?

[S-Works]

Yes they do require a lot of power and it needs to be "clean".

[Basil]

I despair when I see a group of people who on the face of it should be intelligent spout such strong opinions on things they know next to nothing. How are we ever going to make any progress or fix our problems if any solutions are immediately dismissed as lies by people who not only know very little but also lack the intellectual curiosity to follow the scientific method to back their claims.
The government told us to switch to Diesel. We expected that they had taken expert technical advice before doing so.
Why now should we believe anything we're told?
My guess? The anti-Diesel thing is another fad like Vegans or the latest diet.

[chevvron]

The government told us to switch to Diesel. We expected that they had taken expert technical advice before doing so.
Why now should we believe anything we're told?
My guess? The anti-Diesel thing is another fad like Vegans or the latest diet.
Course it is. It's just the basis of an excuse for the government to put even more tax on diesel fuel and collect more revenue from diesel lorry and train operators.

[soay]

David King, the former chief scientific adviser has admitted it was wrong to cut fuel duty on diesel vehicles (https://www.theguardian.com/environment/2017/apr/04/fuel-duty-cut-for-diesel-cars-was-wrong-says-ex-chief-science-adviser) after being hoodwinked by the car industry.

He said the government at the time wanted to encourage more people to drive diesel cars because they were said to emit less carbon dioxide than petrol vehicles. He said he was aware of warnings that diesel vehicles produced more toxic nitrogen dioxide, but he and the government had wrongly assumed this could be controlled by new technology and European regulations.

“I was in very close contact with the industry that was producing these catalyst trap systems and I was convinced that they could manage the problem,” he said. “What we know now, from the Department for Transport emission results from very extensive tests of vehicles, is that a large number of diesel-driven vehicles on the road in London are emitting more than 12 times the Euro 6 limit.”

Asked whether he was misled by the car industry, King cited the Volkswagen emissions scandal. “They [VW] were designing into the engine of vehicles a system that would in effect produce a very good result on the test bed and then deteriorate when it was on the road,” he said.

But King said all diesel car manufacturers “are managing a system whereby the test bed produces the results they want”.

Of course, this justification will carry no weight for those who deny the overwhelming evidence that our emissions of CO2 are destabilising the climate. Such people tend to fall into either the "It is difficult to get a man to understand something, when his salary depends upon his not understanding it!" camp, or are conspiracy theorists. Either way, no new evidence will ever induce them to change their minds, unlike David King!

[ShyTorque]

I own a BMW 3 litre diesel car. The inside of the exhaust tailpipes are as clean as a whistle, bare metal, after almost 100k miles and 11 years. On the other hand, the tailpipe of my other cars (petrol engines) have sooty deposits. In view of the recent bad publicity about diesels I sometimes feel slightly guilty about keeping it, but if I sell it someone else will get the benefit; it's a long way from scrap condition. It's also the most economical on fuel. So it's staying.

[chevvron]

All this concentration about CO2 emissions, rather than 'de-stabilising the climate', people forget that CO2 is broken down by vegetation and thus contributes to the ecology (grow more vegetation and more CO2 will be absorbed) whereas if you compare the CO emisions of diesel and petrol cars there is a vast difference because diesel engines only emit tiny amounts of CO compared to petrol engines. It's commonly know that if you run a petrol engine in (say) a garage with the door closed, you will die of CO poisoning, but do the same with a diesel engine and you might get a headache, but that's all.
On the issue of particulates, these are emitted by both diesel and petrol cars with diesel cars producing them at the same (low) level throughout the life of the car due to the 'particulate trap' fitted to the exhaust, however with petrol engines, the amount starts off low with a new cars and steadily increases over the life of the car ending up far exceeding the amount emitted by diesel engines.
By the way, the sooty deposits in the tailpipe of petrol cars are due to the unleaded petrol being used nowadays; leaded petrol, although more harmful in the long run, was 'cleaner' in terms of soot deposits. The same goes for spark plugs; once upon a time a sooty spark plug indicated the mixture was too rich whereas a 'normal' mixture was a brownish deposit on the electrodes or even clean electrodes; nowadays the 'norm' is to have sooty spark plugs.

[Crash one]

I despair when I see a group of people who on the face of it should be intelligent spout such strong opinions on things they know next to nothing. How are we ever going to make any progress or fix our problems if any solutions are immediately dismissed as lies by people who not only know very little but also lack the intellectual curiosity to follow the scientific method to back their claims.

So how does the non scientific general public user find out the real truth?
I was told that to burn a gallon of petrol produces about three quarters gallon of water, which is pretty harmless stuff. What does the other 25% consist of and what is the genuine comparison with diesel?
Is there an honest, genuine organisation devoted to finding the truth, or are they all employed to produce a result that will satisfy someone's financial interest?
Or are the answers to these questions so bloody obvious they don't need asking?
All the time people making various claims are relying on the results for their own salaries, no one is going to trust anything or anybody.
The same krap is going to happen with electric motors, what cost in emissions will there be if power stations are used to recharge, manufacture batteries, build the new infrastructure?
There's no such thing as a free lunch.

[londonblue]

So how does the non scientific general public user find out the real truth?
I was told that to burn a gallon of petrol produces about three quarters gallon of water, which is pretty harmless stuff. What does the other 25% consist of and what is the genuine comparison with diesel?
Is there an honest, genuine organisation devoted to finding the truth, or are they all employed to produce a result that will satisfy someone's financial interest?
Or are the answers to these questions so bloody obvious they don't need asking?
All the time people making various claims are relying on the results for their own salaries, no one is going to trust anything or anybody.
The same krap is going to happen with electric motors, what cost in emissions will there be if power stations are used to recharge, manufacture batteries, build the new infrastructure?
There's no such thing as a free lunch.

Funny, I asked a colleague a similar question. I asked whether we benefit from recharging vehicles, or do we just displace the issue from the town (with petrol/diesel) to the area around the power station (with electric)?

His answer was that his understanding is that there are economies of scale from recharging because the incremental increase in emissions from the power station are lower than from diesel or petrol. (Even more so if the power isn't supplied by fossil fuels.)

Of course this may not be true, but it was his truthful response in that he isn't paid by anyone to answer the question in any particular way.

[soay]

So how does the non scientific general public user find out the real truth?
I was told that to burn a gallon of petrol produces about three quarters gallon of water, which is pretty harmless stuff. What does the other 25% consist of and what is the genuine comparison with diesel?

Well, the first rule is to avoid web sites which have been set up to deliberately obfuscate the damage caused by burning fossil fuels, such as WUWT and the GWPF.

The products of combustion is fairly basic chemistry as described here (https://www.e-education.psu.edu/egee102/node/1951): "Carbon dioxide is the principal product of combustion of fossil fuels since carbon accounts for 60–90 percent of the mass of fuels that we burn."

Diesel emits 2.68 kg of CO2 per litre while for petrol it's 2.31 kg - source (https://people.exeter.ac.uk/TWDavies/energy_conversion/Calculation%20of%20CO2%20emissions%20from%20fuels.htm).

Note that a litre of diesel weighs about 0.87 kg, so it emits more than its own weight in CO2. That's because each atom of its carbon combines with two atoms of oxygen.

[ShyTorque]

It's commonly know that if you run a petrol engine in (say) a garage with the door closed, you will die of CO poisoning,Not if it's a car engine produced in the last three decades or so!

At least, not if it has a catalytic convertor working as per its design. It converts CO to CO2 (and to a lesser extent, excess HC to CO2 as well), that's exactly why it's there!

The last MOT emissions result I got, for my year 2000 petrol car gave CO = 0.00 % vol, HC = 5 ppm at fast idle and CO 0.01% vol. at natural idle. I think you'd be alive in the garage for quite some time at that rate. Other methods of doing yourself in are far more efficient!

I certainly agree that modern petrol fuels emit more soot than the old leaded stuff; I have been building and tuning my own engines for over 40 years; I began when performance cars needed 4 and 5 star petrol.

I re-jetted a carburettor equipped motorcycle only last week after making some induction improvements. it now runs far better than standard. A couple of years ago I tuned the mixture on my SU carb equipped modified car after a rebuild (this involved hand modifying mixture needles). To confirm everything was all OK I took it for a rolling road session before we did a long distance touring expedition. The operator was very impressed that according to his highly sophisticated Lambda machine I'd managed to get it stoichimetric by eye, using the spark plug colours. He suggested I richened it up very slightly to improve the power output.

[Basil]

soay, according to your Transport conversion table, Diesel cars produce less CO2 than petrol as follows:

Small car -29%
Large car -48%
Average car -40%

I must say, I was a little confused by the heading:
Vehicle type Kg CO2 per litre
which then goes on to express CO2 in Kg/km

[soay]

soay, according to your Transport conversion table, Diesel cars produce less CO2 than petrol
That's why the government promoted diesel engines over petrol, because it's the CO2 emissions which are changing the climate. Diesel contains more carbon per litre than petrol, but that's compensated for by its better MPG. For example, the diesel engined DA40 consumes only 5.6 usg/hr (of Jet-A1) at an IAS of 116 kts.