Are you worried about the future of diesel cars?

[Nasher]

When you load up a car with 5 people and a few suitcases etc the petrols will suffer more than the diesels.

That depends on the power of the engine. Not the type of fuel it uses. But with a diesel engine you have the equivalent of a couple of extra people in weight all the time. Which is one of the reasons they are always slower than the petrol equivalent.

 

[Simon]

I love how this has become the accepted narrative now and everyone just glosses over the fact that we massively tax fuel and as a result the market priorities using as little of it as possible.

Company cars aside there isn't much of an incentive to get diesel beyond the often significant fuel consumption benefits.

Mine for example is only 40 quid a year less to tax than the petrol version.

Diesels are a consequence of decades of European government fuel duty policies.

Do people in Dubai buy diesel cars?

Well diesel is much cheaper per MJ than gasoline. So it has always been an unlevel playing field. Diesel has been incentivised as it should/could have been taxed 15% higher.

 

[Mercenary Keyboard Warrior]

By a trivial amount! Maybe 1mpg?

5% Thats assuming your 20mpg and 1mpg
You wouldn't refer to 5% pay rise as trivial

Reality is we don't know, driving style will make more diff than that granted.

The type of environment as well, when I drive in London I drive far worse economywise for a diesel as I do when in Cambridge. In london if your not sticking to the car in front someone will be aiming for your gap so you have to drive a diesel even further from economically, in Cambridge you can leave a gap, so drive more to suit the diesel torque rather than racing to close the gap.

No one knows the reality as the government figures are worthless. The urban figure is supposed to be this but its clearly nigh on useless for real world consumption.

I used to be FD for a business with a really large fleet of commercial and cars, fuel bill was into 6 figures a month. We pretty much only had diesels, the guys in London got around 30-40mpg from Mondoes to Focuses to 3 series etc, this didnt change noticeably year on year despite ever increasing claimed manufacturers MPGs. Being such high users we did talk monthly at board meetings about fuel (it was also when we were seeing the £1.50 a litre pricing), it was from memory our third highest cost item after staff and rent.

We had someone argue for ages to be allowed a petrol, and in the end the fleet manager relented. It was supposed to be a fuel efficient one, they then got sacked about 6 months later and was replaced by someone who was given the car. Same role as everyone else, they got under 20mpg just like the first person. In the end we changed that persons car out and they immediately went to the same sort of MPG as the rest in diesels. Completely unscientific granted. It was "funny" in a way because part of the reason the first guy got sacked was because the fleet manager was insistent he was fiddling fuel and no way could his MPG be so low.

 

[Mercenary Keyboard Warrior]

That depends on the power of the engine. Not the type of fuel it uses. But with a diesel engine you have the equivalent of a couple of extra people in weight all the time. Which is one of the reasons they are always slower than the petrol equivalent.

No its how the engine generates the power from how the fuel is burned.
Lets not get into the whole debate on torque vs BHP.
Diesels are far less impacted by loads than petrol, its why anything that will haul weight will use diesel because petrol are low torque (comparatively) and rely on revs to generate power.

You can't compare diesels to petrol based on speed because they are different, yes the same in that the use a liquid fuel but the nature of the combustion process is different.

Its more like 1 person. Take the Audi TT 1.8 180ps vs the 184ps diesel, its 55kg diff (1210 vs 1265)
Just picked that as its on my desk, but for sure every model will vary and the gap has widened on some now due to smaller petrols.

Add 3 average people thats about 180kgs and say 60kgs of luggage. Thats not an insignificant 240kgs, or about 20% extra weight, you will notice less impact in a diesel than a petrol.
Mainly because due to the torque you will not work the car as hard to keep acceptable performance, with the petrol you will tend to rev harder and hence use more fuel

 

[Nasher]

Lorries use diesel because it's cheaper to run them on it.

 

[Mercenary Keyboard Warrior]

Lorries use diesel because it's cheaper to run them on it.

And why is that as the fuel is no cheaper
Is because a diesel will do more work for the same cost, its just far more obvious as the weight goes up
Have a look at some of the old range rovers petrols vs diesels for example

Anyway, was googling a bit over my canteen supplied fake Nandos chicken lunch, turns on the AA did a bit on this area a few years ago

• Getting stuck in a traffic jam is another daily problem with winter driving. Even with a warmed-up engine, a petrol car can lose at least two-thirds to three-quarters of a litre of fuel every hour, or 1.2 to 1.4p a minute. A diesel car can lose a third to half a litre of fuel an hour, or 0.6 to 1.0p a minute.

May even be a little more than Foxs' 5%
Ignoring the cost although costs are currently quite similar actually per litre of fuel, its quite clear that diesels will use less, every test indicates they do, just the numbers will vary.

few other interesting snipets we all knew but they at least tried to measure:

"Warming up an engine's oil in cold weather and greater use of heaters, windscreen wipers and lights account for the three per cent increased engine workload. Even at relatively mild winter temperatures, the fuel consumption of a cold car leaving its driveway is 40 per cent higher than normal."

• Even at a relatively mild outside temperature of +10C, a car's fuel consumption for the first mile will be around 40 per cent higher than with a warmed-up engine. This falls to around 16 per cent over the next three miles and, even up to 6.5 miles from start-up, fuel consumption can be 8 per cent higher.

This I am more surprised at frankly, I never would have said 40%!
But they broke it down a little more

The increase in fuel consumption due to cold weather is similar for both diesel and petrol cars. AA tests show extra fuel use after 1 mile and 3 miles respectively are:

• typical small petrol car – 34% and 17%
• medium petrol car – 38% and 16%
• small diesel car – 32% and 12%
• medium diesel car – 43% and 18%

Quite interesting how significant they made out the impact to be. Just goes to show how significantly down on MPG the cars are. Throw in the extra work for demisting and heating and you can see why MPGs drop for the winter season!

http://www.theaa.com/motoring_advice/news/aa-fuel-for-thought-increased-cost-of-winter-motoring.html

 

[jigger]

My diesel is not particularly efficient in stop start traffic from cold. It's sometimes as low as 20mpg in such conditions.

Of course it's not. You have heater plugs and a much higher compression ratio. Some cars fire all the injectors at start too. It takes a lot more energy to start a diesel than a petrol.

 

[Vertigo]

Other than direct injection, the ability to run without directly controlling the throttle plate (BMW Valvetronic), Fiat's Twin-air that allows two valve openings during a single induction cycle, moving turbos from being the preserve of specialist cars to general driving,VNT turbos there have been absolutely no developments in petrol engines.

Cylinder shutdown?

I drive a 1.4L petrol which produces 150bhp and will happily do 50mph on a long run. Not many years ago that would have been unheard of.

 

[Simon]

And why is that as the fuel is no cheaper
Is because a diesel will do more work for the same cost, its just far more obvious as the weight goes up
Have a look at some of the old range rovers petrols vs diesels for example

Hardly the best comparison. A old petrol na engine vs a turbo diesel.

Any case, as said higher up diesel does give more energy per litre which is a huge factor in its adoption.

that fact on idling needs some thosort got behind it. Half a litre in an hour is nothing. In that same hour you could go 70miles and use 8-9 litres of fuel.

 

[Simon]

Double post

 

[Jonnycoupe]

I love how this has become the accepted narrative now and everyone just glosses over the fact that we massively tax fuel and as a result the market priorities using as little of it as possible.

Company cars aside there isn't much of an incentive to get diesel beyond the often significant fuel consumption benefits.

Mine for example is only 40 quid a year less to tax than the petrol version.

Diesels are a consequence of decades of European government fuel duty policies.

A) you don’t need to talk as though I’m a moron.
B) you are applying your logic as appropriate for the general public.

Company car CO2 banding over the last decade was a big push for some of the change.

Only yesterday I had to wait ages for some old chap to move his car off the road into a gated apartment complex in his diesel Corsa, I thought i was at farmer Geddons barn....

Then we had the scrapage scheme and the tax where superminis that cost significantly more in diesel flavour. I was only in a mini garage on Sunday when a young girl about to trade in her mini and sign up for PCP after agreeing for £395 of lifeshine care mention the fact it was so much cheaper to tax the new one!!

The point I was replying to was still relevant anyway.

 

[Mercenary Keyboard Warrior]

Hardly the best comparison. A old petrol na engine vs a turbo diesel.

Any case, as said higher up diesel does give more energy per litre which is a huge factor in its adoption.

that fact on idling needs some thosort got behind it. Half a litre in an hour is nothing. In that same hour you could go 70miles and use 8-9 litres of fuel.

Whilst the half a litre isnt a lot granted thats beside the point, the point was that diesels are more efficient in that area as well, and people disputed based on I am not sure, Foxs OBC maybe.

Not sure how what could have been done driving 70 miles adds, maybe you were going to add that it could also have been 5-6 litres in a diesel? or 25 litres in an old Stang, I am sure you wanted to add some relevance just not sure what to a conversation about economy in stop start?

Its true its almost impossible to compare diesel to petrol. Because we do a broad pick a car and try to compare engines but then to really compare something you should match the key criteria and thats nigh on impossible to do real world for car engines as they just don't exist. I was trying to think of something heavy that I knew came in both variants but I agree wasn't a good choice. Can you suggest a heavy vehicle thats available in a broadly similar petrol and diesel variant that could be used to assess the urban?

 

[Joe T]

Only yesterday I had to wait ages for some old chap to move his car off the road into a gated apartment complex in his diesel Corsa, I thought i was at farmer Geddons barn....

I doubt that that diesel Corsa was originally a company car. More likely bought for the high MPGs, which is Fox's point.

 

[Mercenary Keyboard Warrior]

I doubt that that diesel Corsa was originally a company car. More likely bought for the high MPGs, which is Fox's point.

probably.
I know someone with a diesel micra, quite old, she commutes 20 miles each way daily, mainly along dual carriageway, and often drives a couple of hundred miles each way at a weekend.
How she puts up with it I dont know, but she also likes the fact its tiny so can get into any spot in the works multistory carpark, I used to work at the same place and there are plenty of spaces I used to hate parking in as they were smaller and hence why they were always the ones left if you nipped out at lunch etc.

Should she be banned from having a diesel because its a small car? Plenty of small cars travel distances as well.
Its what the car is used for thats key, plenty of big diesels sitting in traffic, plenty of petrols doing daily motorway/dual trips that would be more suited to diesel

Maybe to get back to the main question a bit more directly

I think rather than being worried about diesel we should expect it may not be the cheap way of motoring it currently is, and that the government should over a period of time (like 10 years) have an escalating tax regime that removes the significant cost benefit of running a diesel to bring it more in line with petrol.
I would keep it just a little cheaper, but make it that its not really noteworthy for anyone doing less than say 12k pa. There are plenty of ways of getting this right for example, maybe the annual tax should be bumped up a fair bit, but the fuel duty on diesel lowered. So the fixed costs are higher and variable lower, should push those doing low mileage away from diesel, but keep the company cars mile munching in diesel rather than petrol.

 

[Nasher]

They won't do much with petrol/diesel now I don't think, except maybe ban diesel from town centers. Which is what London is already working towards.

With EVs on the rise they will be focusing on making those more expensive to run. Theres no way they will let people buy old, tax free EVs and then charge them up at home for peanuts forever.

 

[inflames]

They won't do much with petrol/diesel now I don't think, except maybe ban diesel from town centers. Which is what London is already working towards.

With EVs on the rise they will be focusing on making those more expensive to run. Theres no way they will let people buy old, tax free EVs and then charge them up at home for peanuts forever.

100% agree, they will have to Tax EVs eventually as they will be slowly start to lose funding for all the ICE cars coming off the road.

 

[Joe T]

They won't do much with petrol/diesel now I don't think, except maybe ban diesel from town centers. Which is what London is already working towards.

The press (inc the FT) disagrees with you and believes that there is a tax change coming in the budget announcement next week.

 

[Amp34]

More nonsense.

The largest EV on the market, charging in a coal-heavy part of the US is comparable to a very small ICE, assuming the rapid decarbonising of the power system that's underway grinds to a halt.

Source

And if you have a green electricity service (as we do, costs us an extra ~8%) then the P100D will have a lifetime emissions total per km of 1/10th of the small ICE car.

It’s not like renewable electric tariffs aren’t available or actually much more expensive than mixed tariffs in the UK or Norh America. And if you’re buying an electric car you’re probably more able and inclined to swallow the extra cost of a renewable only tariff anyway.

What will happen after diesel cars are taxed into the scrap yard a new study will find out the issues with small turbo direct injection petrol's that everyone one switched to and a government think tank will tax them out the market and we will be back into large NA port injection petrol's maybe America was right all along

I was reading an article where in the high pollution zones a large percentage of pollution is caused by heating properties and the government want to move away from gas boilers to reduce this. Just wait until a modern day house hold fires up a 20-30KW electric boiler followed by charging two cars with 30kw fast chargers the power grid will collapse

Even North America is moving away from the large NA engine now. Ironically diesel is just starting to become more popular, but only in larger vehicles and the large V8 engines in those vehicles are now being replaced by smaller turbod V6 and 4s. They’re actually becoming more popular as they have slightly better performance.

 

[Nasher]

Well for a long time the US didn't have small, fast, European/Japanese cars. The big V8s were the only real option for anything remotely fast. It's kind of a "new" things for them.

 

[Deleted User 234324]

I'm not at all worried about it, in-fact sooner its gone the better, bring on the electric revolution. Be interesting to see what Tesla reveal tonight with the electric truck.