Are they really dead? Is the new Mercedes (not quite new) Diesel engine likely to breath life into the technology?

Depends on economics.

Their life is coming to an end diesel sales have been very poor of late.

Looking to replace my C class estate later this year with the same. It’s a petrol and I do less miles than I used to so it doesn’t make sense to switch to a Diesel now but I was suprised watching some of their videos that they were releasing a new one. Unless its just an attempt to wring as much as possible out of their diesel technology before admitting defeat.

New diesel engines are compliant with the latest standards that the EU require and will not be prevented from entering cities for example as far as I’m aware, it is older diesels that are the problem, but the press has put fear into the public who now believe all diesels are bad so are not buying them.

I still would not buy one, but that is because I don’t need one for the driving I do.

Problem is that CO2 levels have already risen as a result of people stopping buying diesels I believe, so we are as a society halting the new problem by going back to the old problem.

Diesels are here to stay, granted there won’t be as many… maybe the split will be 50/50 instead of the 75/25 split it has been.

Even with the higher taxes it is still more efficient and thus lower CO2 and fuel costs than petrol and petrol hybrid equivalents for people doing high miles.

What bikebouy said.

If your vehicle is big enough, or you do big miles, then diesel is the way to go.  Remove all the ‘small/low miles’ diesels and a big chunk of the problem goes away. That includes our Golf!

Diesels are here to stay

Not as the only power source they’re not same as petrol.

Merc it would seem have some of the better real world emissions results as in they stack up to the claims in real world testing not just on the dyno. Still looks like diesel will be out of favour at least until everyone has bought a petrol or hybrid. Then maybe it will come back for one last go before it’s electric or walk.

I suspect  miss-selling small city car diesels has caused much of this issue. Short journeys, never get properly warm, DPF issues due to this and spewing lots of crap out

Mazda’s new compression-ignition petrol engine might chuck a small spanner in the works, offering similar torque and efficiency to a diesel, without the particulate issue, introduced next year.

I’ve just read a story on the BBC website about the massive decline in diesel car sale in the last month. It really was poor journalism at its finest. Not a single fact or figure, just generalisations on diesels are bad, and people are stopping buying them, no mention of EU5 or EU6 engines nor the older engines, which are the real problem. The big problem is commercial transport, but there is little or no pressure to be put on the road haulage associations of europe. About 15 years ago, I was a very small part of an idea to put trailer units straight onto the railways. Tetley’s brewery built a few, with the idea being they were loaded up at the brewery, taken on a very short journey to the local rail depot, and put straight onto a buggy, and off they went. I distinctly remember a man from the rail terminal saying with no investment whatsoever, they could take 40% of the heaviest lorries off the road immediately, and with very little investment over 70%. I never saw or heard of that again.

Sorry, off on a tangent somewhat, but…….I feel the average driver is an easier and more lucrative option here, and in no way tackling the real issue.

In saying all that…..we’ve just got a new car……first petrol in 20 years!

Mazda’s new compression-ignition petrol engine might chuck a small spanner in the works, offering similar torque and efficiency to a diesel, without the particulate issue, introduced next year.

It does seem to be everything to everyone and is actually produces less pollution then EVs based on current energy infrastructure and that DOESN’T include the cost of production the batteries.

@andy8442

Freightliner?

Problem is that CO2 levels have already risen as a result of people stopping buying diesels

That is because the average size of new car has gone up, not because of switching from diesel to petrol.

Indeed, what we all need to be driving is something the size/weight of a twizy, not an x5.

The amount of driver only x5 size cars i see going about is amazing (not in a good way)

Petrol…offering similar torque and efficiency to a diesel

We’ll see. I’m no expert, but unless they’ve figured out a way to compress petrol in storage, diesel will always have more calories per litre, which is largely why diesel is more ‘efficient’ than petrol, when compared using distance per unit of volume.

I don’t think diesel is a better fuel than petrol per se, but it’s more energy dense. When we buy it by volume, that’s kind of fundamental.

Well i just picked up my new car today and its a……….diesel. They suit me for the milage i do. I looked at petrol engines but for the driving i do they just did not make sense to me. I reckon deisels still have a place in thr car market.

Iirc a lot of the UK’s refineries are set up to.produce diesel, or at least more diesel than petrol, guessing it’s quite a long term thing to change them.  Maybe diesel prices will come down if there’s surplus production when fewer diesel cars are being bought. Or more likely tax will go up to compensate…

The petrol engine in the latest Range Rover PHEV produces 404HP from under 2 litres and 640NM torque
Lifespan of batteries seems better now; 100000 miles/8years on the RR PHEV, but only 31 miles range in full EV mode

I’m not sure that battery-power is the way to go, too many threats to their continued production beyond the short-term, e.g. weight, materials, disposal, production/environmental costs, etc
So, petrol for me with an alternative fuel (hydrogen cell?) in the future

PS Just re-reading that, those PHEV engine outputs will be from blended petrol-electric mode

I don’t see this move as much more than car companies, having sold us ‘wrong’ car for the job (diesel for short city journeys) now selling us more cars (petrol), while sneaking in more hybrids and electric so that every few years they can persuade us to buy another vehicle…

Our biggest issues are too many short journeys and cars that are still not being kept long enough.

I do 20-25k a year, all over Scotland and North England. Diesel works brilliantly for me.

I’m also predicting the ‘battery problem’ of both a short lifespan and difficulty recycling the things in 5 years time.

@drnosh- not frieghtliner, a lot more complicated than that.

Iirc a lot of the UK’s refineries are set up to.produce diesel, or at least more diesel than petrol, guessing it’s quite a long term thing to change them.  Maybe diesel prices will come down if there’s surplus production when fewer diesel cars are being bought. Or morelikely tax will go up to compensate…

I’ve read It’s actually the other way around, we export Petrol and import Diesel. The odd thing though is that as I understand it (Dad works for an Oil Producer) is that a barrel of crude will produce 19 gallons of Petrol AND 11 gallons of diesel rather than either or.

diesel will always have more calories per litre, which is largely why diesel is more ‘efficient’ than petrol, when compared using distance per unit of volume.

Don’t think this is true. AFAIK it’s down to higher efficiency of the engine due to direct injection, higher compression ratio and lack of throttle (or less throttle at least).

But it depends how you measure efficiency. Miles per gallon or per unit CO2?

The odd thing though is that as I understand it (Dad works for an Oil Producer) is that a barrel of crude will produce 19 gallons of Petrol AND 11 gallons of diesel rather than either or

Yes, although as I understand it, that ratio can vary depending on the type of crude. And some diesel is produced by cracking heavier oils, which takes even more energy.

Why don’t manufacturers make a diesel/hybrid ? They make petrol/hybrids so why not combine the best mpg with electric self charging hybrids..

Surely someone has thought of this?

I tried googling it, but came up blank.

Saying hybrids are the future is misleading, same as saying petrol is or even EV. Thankfully we live in an environment where people’s requirements are vast and complex, and there’s a space/niche that fills most of thier future requirements.

I wonder why this government are so against diesel, maybe they are thinking more tax revenue is gained by less mpg petrols..

Currently Lexus are unveiling a new hybrid, UX250h.. a sort of small SUV.. with mpg in the mid 30’s.. which seems mighty odd considering my RX300h can get 58-65 in my real world driving.

Currently Lexus are unveiling a new hybrid, UX250h.. a sort of small SUV.. with mpg in the mid 30’s.. which seems mighty odd considering my RX300h can get 58-65 in my real world driving.

Where are you seeing that number? From the blurb I read it sounded like it was going to be a lot better than that

Modern petrol cars get ridiculously good mpg, i’d be going that route if I wanted a new car, at least until electric cars are a comparable price and fast charging infrastructure in place.

Unfortunately I like vans, and there just isn’t many non-diesel vans, other than the small car-based ones, so i’m hoping i’m not shafted by LEZ in Bristol in the next few years.

Commercial panel vans and lorries will be diesel for a very long time yet.

Diesel with no NOx emissions? It may be possible, and coming soon

<div class=”bbp-reply-author”>molgrips
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diesel will always have more calories per litre, which is largely why diesel is more ‘efficient’ than petrol, when compared using distance per unit of volume.

Don’t think this is true. AFAIK it’s down to higher efficiency of the engine due to direct injection, higher compression ratio and lack of throttle (or less throttle at least).

But it depends how you measure efficiency. Miles per gallon or per unit CO2?

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You are confusing clarofic value of a carbon vs the mechanical efficiency in which it is consumed.  The statement that diesel holds more calories is correct, much like wood has more than diesel, but you cannot efficiently exploit that potential energy the same in all cases.

Diesel as stated is not going anywhere especially in the transport and freight sector, the efficiency of other fuel types are nowhere near what is required/ or can be stomached by the consumer as the alternatives would encure unbearable costs.  That said, there are various EU and UK gov funded schemes set up to encourage new technologies that are low energy consumption to provide drop in replacement fuels.  You also have the issue of, what do you do with all of the heavy cuts of crude once you’ve taken and used the gasoline fractions??

On the point of the Mazda engine, there have been a few people looking into GCI, have a look at the Saudi Aramco / IFP collaboration / Achates Power engines.  They’ve also been looking at Octane on demand

What happens in the sensible Scando countries? Just do the same is the easy answer.

Our decisions are too weighted towards commercial interests.

Why don’t manufacturers make a diesel/hybrid ? They make petrol/hybrids so why not combine the best mpg with electric self charging hybrids..

Peugeot / Citroen had one for a few years, it made 200Bhp and produced 99g/Km which wasn’t bad considering they were all 4WD (although that might be because the ICE drove the fronts and the battery the rears or something). It didn’t take off. Too expensive to produce and too small a market! Seems ‘only Europe’ isn’t big enough to warrant a new type of hybrid.

<div class=”bbp-reply-author”>wilburt
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What happens in the sensible Scando countries? Just do the same is the easy answer.

Our decisions are too weighted towards commercial interests.

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Not quite the case.  Both Sweden and Finland have large oil companies that have been looking at renewable’s for years, they are massively ahead of the rest of Europe in that case.  Finland has NESTE oil that pioneer the fischer tropsch process of converting biomass to synthetic fuel for commercial use (SASOL in SA have been producing JET using the same process bu different feed stocks for years), which has a similar (although importantly) not the same characteristics of diesel.  This is found in large % >30% of the fuel.  Sweden, have been using ethanol for 20 odd years, even in heavy duty industry with ED95, of course and getting back to points above they are not as efficient as normal DCI.  France has also just introduced ED95 for heavy duty, but it is likely to be heavily subsidised.

Northern Europe is so driven by politcal games that it’s either like getting a super tanker to turn, or those decisions that do happen quickly happen with very little scientific thought or input as the “data” is always fed by interested parties.

Intresting but not really related to private transport.

Northern European countries seem more likey to encourage electric (Norway 50% of new sales) vehicles and facilitate walking and cycling for short journeys and have better trains and trams four mid to long journeys.

Whilst our goverment is sponsored by road haulage and vehicle manufacturers who are doing ok from the status quo so less keen on progressive change.

They may occasionally make noises about “sustainable transport etc” but in action do little to nothing.

I think there are diesel free solutions to transport, even heavy goods but theres no business model in place to benefit the usual suspects so we will be chucking around for quite a while yet.

ps: we have two diesels and two petrols, next car likely to be electric but as well as not instead of the others.

Don’t think that is true

But it is. And modern Diesel engines are excellent at exploiting the fact.

‘The calorific value of diesel fuel is roughly 45.5 MJ/kg (megajoules per kilogram), slightly lower than petrol which is 45.8 MJ/kg. However, diesel fuel is denser than petrol and contains about 15% more energy by volume (roughly 36.9 MJ/litre compared to 33.7 MJ/litre).’

(Sauce; http://www.acea.be/news/article/differences-between-diesel-and-petrol)

Wood has more (energy) than diesel

Per litre? Lol. I somehow doubt it. But your point about exploitation of energy certainly stands. Exploiting a solid fuel rapidly is much more difficult than exploiting a very volitile liquid, which is in turn (until Diesel engines got so good) easier than exploiting an energy rich but much less volitile fluid.

if you consider that diesel has 15% more energy than petrol per litre, and then look at real world economy of petrol vs diesel, measured in distance per litre, there’s a definite correlation. I’m sure a clereverer person than me could prove causation too.

If we suddenly started selling road fuel either by weight or by calorific units, it would turn the conventional thinking about fuel economy on its head.

anyway, enough of this; I’ve just got up after a night shift and IT’S THE FIRST SHORTS DAY OF THE YEAR!!! YES!!!!!!!

“We’ll see. I’m no expert, but unless they’ve figured out a way to compress petrol in storage, diesel will always have more calories per litre, which is largely why diesel is more ‘efficient’ than petrol, when compared using distance per unit of volume.”

Well diesel might be more calorific but its all about the machine used to extract those calories and how efficient it is  because 100% of the calories locked up in the fuel is not liberated and work done from it. Most of it just generates wasted heat and energy in the exhaust. SO it doesn’t matter if petrol has less energy density than diesel – it matters more if the machine can extract more of the locked up energy.

In these new variable compression ratio engines when in the diesel cycle fuel is not injected in the induction stroke, the air is compressed then fuel injected into the already compressed fuel. Obviously it immediately burns due to the pressure and temperature of the compressed air, but the problem of knock is avoided because you’re not compressing the fuel with the air. So you can burn petrol at much higher pressures and temperatures than you can in a spark ignition cycle and therefore extract more energy from the fuel and do more work. One of the benefits of petrol is that it burns faster so can achieve higher piston speeds – one of the reasons petrol engines still dominate motorsport- when you have a fixed capacity engine the only way you can get more power is to increase rpm which you have a severe rpm limit with diesel engines engines, so maybe you can get better efficiencies than diesel fuel engines for some of the other more attractive properties of petrol. Anyway, I’m no expert either, but these things have been under development for a good 15 years or so now and from what I’ve read about they they do achieve the best of both worlds regarding performance, emissions and fuel economy.

The statement that diesel holds more calories is correct

Ok I can see how you’d misunderstand my post, I didn’t write that very well.

What I meant was, it’s not true that the reason for diesel engines’ increased efficiency is the increased calorific value of diesel.  There are a number of reasons, as I stated, and I don’t think the calorific value is the biggest one.