Is diesel a dead end as a technology?
Discussion
Max_Torque said:
Within as little as 3 -5 years and even now to a large degree, the type of fuel you are putting in your car is almost irrelevant to the technology under the bonnet!
ALL engines will have high pressure common rail injection systems, with pressure charging and EGR. Current GDI's are now over 200bar (ok, a lot less than current diesels, but once you're over about 50bar the injector technology is pretty much the same) I suspect that as the number of DI cars grows and the fleet ages, many more sources will appear for "aftermarket" recon/supply of fuel system parts etc. (with a corresponding fall in costs to the man in the street!!)
As managing the combustion process becomes even more critical to the fuel economy and emissions systems there is no way that petrol engines will just stagnate on the current technology level.
The latest downsized pressure charged VGT gasoline engines basically make 100nm/litre (min) between 1500rpm and 6500rpm, and the latest pressure charged DI engines pretty much match that except right at the top of the rpm range (approx max 5.5krpm) They are basically the same engine now. (DI have much better combustion systems to improve burn rate and hence high rpm performance, GDI's now have to make high torque at low rpm (to support downspeeding for max FE) so end up having peakl power moved down, the result, they are meeting in the middle)
The only long term advantage of diesel as a fuel is that as we get to the end of the oil reserves, diesel (without the lighter fractions required in gasoline) is easier to refine from "poorer" grade crudes.
Interesting read - thanks.ALL engines will have high pressure common rail injection systems, with pressure charging and EGR. Current GDI's are now over 200bar (ok, a lot less than current diesels, but once you're over about 50bar the injector technology is pretty much the same) I suspect that as the number of DI cars grows and the fleet ages, many more sources will appear for "aftermarket" recon/supply of fuel system parts etc. (with a corresponding fall in costs to the man in the street!!)
As managing the combustion process becomes even more critical to the fuel economy and emissions systems there is no way that petrol engines will just stagnate on the current technology level.
The latest downsized pressure charged VGT gasoline engines basically make 100nm/litre (min) between 1500rpm and 6500rpm, and the latest pressure charged DI engines pretty much match that except right at the top of the rpm range (approx max 5.5krpm) They are basically the same engine now. (DI have much better combustion systems to improve burn rate and hence high rpm performance, GDI's now have to make high torque at low rpm (to support downspeeding for max FE) so end up having peakl power moved down, the result, they are meeting in the middle)
The only long term advantage of diesel as a fuel is that as we get to the end of the oil reserves, diesel (without the lighter fractions required in gasoline) is easier to refine from "poorer" grade crudes.
The thing is though, that the cost of the tech is one thing, but it's the labour costs for changing the failed components that is just daft. To change fuel pump or SCV is a massive job on some diesels. It can't be beyond the designer to streamline this activity to offset some of the material cost - can it?
rhinochopig said:
The thing is though, that the cost of the tech is one thing, but it's the labour costs for changing the failed components that is just daft. To change fuel pump or SCV is a massive job on some diesels. It can't be beyond the designer to streamline this activity to offset some of the material cost - can it?
Interesting point really - doesn't the design ultimately cost the brand whilst its in its warranty period as they are shelling out for labour?If I recall the 330d fuel pump is buried somewhere deep in the engine!
Just me that remembers when Diesels were the simple reliable choice as petrols became all computerised??
Still, having swapped back and forth for years, its going to take a very special diesel to convert me back!
I think its all going to go Hydrogen, LPG, Biofuel and Hybrid long term....
Rudolf Diesel's first engine ran on Coal Dust, and I don't see any "Coal Dust" refilling stations....
Still, having swapped back and forth for years, its going to take a very special diesel to convert me back!
I think its all going to go Hydrogen, LPG, Biofuel and Hybrid long term....
Rudolf Diesel's first engine ran on Coal Dust, and I don't see any "Coal Dust" refilling stations....
V88Dicky said:
It is quite startling the amount of people I've overheard mentioning 'bloody egr valve again' or 'that stupid dpf filter thingys gone tits up again' or 'thats its second set of glow plugs this year' when talking about their cars.
Seems the more the car manufacturers try to 'improve' dervs, the less reliable they become.
A good mechanic friend of mine works at a combined Jaguar/Aston dealership, and when he found out my good lady wife had put a small deposit down on a 3 year old Jaaag, the first thing he said was; "You haven't bought the diesel, have you?". When I inquired why, he mentioned that the vast majority of warranty and breakdowns that they dealt with, was with the 2.7 twin-turbo diesel that Jaguar use.
Glad the missus opted for the petrol
perhaps it's simply the more popular choice?Seems the more the car manufacturers try to 'improve' dervs, the less reliable they become.
A good mechanic friend of mine works at a combined Jaguar/Aston dealership, and when he found out my good lady wife had put a small deposit down on a 3 year old Jaaag, the first thing he said was; "You haven't bought the diesel, have you?". When I inquired why, he mentioned that the vast majority of warranty and breakdowns that they dealt with, was with the 2.7 twin-turbo diesel that Jaguar use.
Glad the missus opted for the petrol
Max_Torque said:
ALL engines will have high pressure common rail injection systems, with pressure charging and EGR.
This is the key thing. The same drivers for this technology in diesels apply to petrols too - more power, better efficiency, lower emissions. Something like the VAG 1.4TSI petrol engine has a 150 bar common-rail injection system, plus a turbo and a supercharger to potentially go wrong. Very few new car buyers are planning to keep that car longer than 6-7 years so the benefits of the tech outweigh the cost of keeping it going under someone else's ownership.
sjg said:
Very few new car buyers are planning to keep that car longer than 6-7 years so the benefits of the tech outweigh the cost of keeping it going under someone else's ownership.
Ultimately the increased depreciation from the higher cost of ownership at seven+ years old will hurt the new buyers though. HellDiver said:
anonymous said:
[redacted]
Pretty much, yeah. After 3 diesels, I'm not going to bother again. All 3 were s
te. OK, two were Vauxhalls, but the other had a VAG TDI PD in it, and it was pants too.The fleet are now all petrol powered as a few quid a week mpg savings are easily wiped out with a 4 figure bill when a turbo goes. As I know from first hand experience.
rhinochopig said:
tenohfive said:
Most people won't pay any attention whatsoever to the cost of replacing the injectors though. Maybe PH'er's but most people won't know any different.
Joe Public see's a motor that's cheap, comfortable to drive, economical and powerful enough to punt about in. Injector costs are unlikely to enter most peoples heads when buying the car.
Until someone with a 6 pot beemer calls watchdog and presents their bill for 6k's worth of injectors, and 3k for a new pump and labour to fit.Joe Public see's a motor that's cheap, comfortable to drive, economical and powerful enough to punt about in. Injector costs are unlikely to enter most peoples heads when buying the car.
German diesel: reliable.
French/Italian diesel: bit of a gamble.
People with more motoring knowledge may well be put off by such costs but realistically the vast majority of the public don't fall into that category.
Edited by tenohfive on Monday 18th October 15:26
The real Apache said:
V88Dicky said:
It is quite startling the amount of people I've overheard mentioning 'bloody egr valve again' or 'that stupid dpf filter thingys gone tits up again' or 'thats its second set of glow plugs this year' when talking about their cars.
Seems the more the car manufacturers try to 'improve' dervs, the less reliable they become.
A good mechanic friend of mine works at a combined Jaguar/Aston dealership, and when he found out my good lady wife had put a small deposit down on a 3 year old Jaaag, the first thing he said was; "You haven't bought the diesel, have you?". When I inquired why, he mentioned that the vast majority of warranty and breakdowns that they dealt with, was with the 2.7 twin-turbo diesel that Jaguar use.
Glad the missus opted for the petrol
perhaps it's simply the more popular choice?Seems the more the car manufacturers try to 'improve' dervs, the less reliable they become.
A good mechanic friend of mine works at a combined Jaguar/Aston dealership, and when he found out my good lady wife had put a small deposit down on a 3 year old Jaaag, the first thing he said was; "You haven't bought the diesel, have you?". When I inquired why, he mentioned that the vast majority of warranty and breakdowns that they dealt with, was with the 2.7 twin-turbo diesel that Jaguar use.
Glad the missus opted for the petrol
otolith said:
I don't think the hushed up misfuelling and the prevalence of chip tuning are going to do much for the reputations of current diesels for reliability a few years down the line.
+1 (being lazy)...All too easy to slap £300 - £400 on the table and get immediate gains with increased strain on already highly stressed components. Few yrs down the line sell/trade in and next owner gets a nice surprise.
Its why all my diesels have remained firmly standard!
It doesnt matter what you do anyway, for example I went auto this time round thinking I would save myself clutch and flywheel issues in higher mileage. The fact the autobox gave up at 59k rather undid that theory somewhat, luckily Volvo footed the bill for that one too.
I do wonder how much the quality of the fuel has a bearing on things too. I can't imagine running poor quality diesel through high pressure systems ever does any good, just as with petrols.
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