Germany’s ‘Diesel Fear’ Leaves $5 Billion in Used Cars Gathering Dust

Transportation, Travel and Trips
41
Certainly not in the UK, I know 1 bank that changes them every 3 months as they could get a better deal by buying 8 times as many cars as changing them every 2 years. The deal is so good, they can sell the cars for the same as they paid new.

42
Looking at 530x based on CH prices. (what I am considering right now)

530xi CHF 74'300

6.5-6.7l/100km

530xd CHF 81'200 (+6900CHF)

5.3-5.5l/100km (-1.2l/100km)

6900CHF buys you more than 3000liters of petrol enough to cover the difference of consumption for 250'000KM. Add costs of adblue and it is even more.

So I was quite generous in favour of diesel when quoting 150-200k kms. Even considering discounts, tax benefits (crazy in light of dieselgate), I am sure I would not keep the car long enough to break even. On the other hand petrol is quieter, stinks less and sounds better.

Also, I hope swiss authorities will catch up and abolish the tax benefits of diesel.

43
say what now?

reliability is definitely on the side of petrol.

44
I always thought diesel engines were more reliable because they're built to withstand a much higher compression ratio.

And I might be wrong but aren't there less moving parts to a diesel engine?

45
I think it used to be like that but now you have the common real, particle filter and other emission systems, turbo etc. the engines just got more complex.

46
Good point, I think a lot of the conventional wisdom is based on these intergalactic mileage monsters

47
Open the hood of a 30 year old car, and open the hood of a modern car.

There is so much more these days that can break down where the engine itself only has become a small part of the whole installation, this led to lowering the trustworthy advantage the diesels had, even if the combustion part never will break down, something else eventually wil.

48
Yes! You are correct. For beginners no spark plug is required. Once combustion takes place it continues until fuel cut off. Actually an effective and relatively efficient technology if used for certain means of transport (i.e. boats, trains, trucks) where the vehicle maintains a predetermined constant velocity. As for cars, most rarely maintain any constant speed and in this case there are better alternatives including gasoline.

49
There is more to say on this, IMHO, e.g. what do you mean by "better". I recently changed from a diesel engine (Renault Clio 75HP) to a petrol engine (Ford Fiesta 75HP) and my fuel consumption has gone from 4.9L/100km to 6.9L/km. Since I am not one of EF's "boy racers", I would like economy, rather than performance. Why is there such a big difference?

50
probably your driving style as that is quite high.

for reference, my 9 year old, 1800 kg, 4wd, 3 liter diesel also does 7l/100km.

51
Wow, 6.9L/km. That's not reduced economy, it's a big leak in the fuel tank!

To answer your question: Diesel has (in practice) a higher energy density than gasoline. Since an IC engine converts the energy stored chemically in the fuel into heat and kinetic energy by ignition, you need to put fewer kilos of fuel into a diesel to get the same amount of kinetic energy (work done to move the car) out.

Compare flambeeing your Christmas pudding with Brandy vs Nitro thinners. Aside from the question of if it's edible afterwards, the same weight of Nitro will give a considerably larger "Oompf" on ignition, likely affecting your eyebrows, tablecloth, guests, and ceiling. Nitro thinners have more energy stored chemically than a sugar/alcohol mixture.

Uncompressed Diesel also burns more slowly than gasoline (which is opposite to the Brandy/Nitro example), but when compressed it's ignition is almost instantaneous. This means that you're able to extract more kinetic energy from a Diesel (per stroke) because the conflagration is more complete by the time you have to open the exhaust valve in preparation for the next stroke. Gasoline engines have a slower flame propagation in compression, so there is proportionally more unburnt fuel in the cylinder when the exhaust valve opens.

52
That ́s what I am talking about, these things can run on oil from the chippy, you do get hungry driving behind a car that has been tanked with chip oil though, but think about it, one Liter of Vita d ́Or from Lidl costs 85 cent and will propel your 200er merc just as good as Oil from a Shell station.

53
Buying vegetable is significantly cheaper in bulk. At the start of my career I worked for a chemical company and employees could buy 50 gallon (Imperial gallons) drums of palm oil for their chip pans. Usually split amongst several people, because 50 gallons of chip pan oil is a lot for one family to get through.

54
It's not the reason why diesel engines are(were) more reliable. It's because they don't have spark plugs.

55
It's not really that simple. The lack of an ignition system to operate and maintain reduces the maintenance a bit, but modern petrol engines are about as reliable as diesels... if you service them properly, and you don't flog the engine.

Because diesels generate their grunt way down in the rpm range, driver's don't rev them up as high (some do, but they don't understand the point of a diesel). Back a few decades ago the lower rpms meant that oil lasted longer, and there weren't as many vibrations and harmonics which needed balancing as in a petrol engine (the higher an engine revs the more often you have to change the direction of the pistons, the less wear you see on sliding surfaces), but modern oils, as well as designs optimized to reduce harmonics mean that Diesel and Petrol engines are more or less neck and neck for passenger vehicles.

Diesel exhaust temps are lower than petrol, and they also run a bit cooler, so they're a bit less prone to wear in the cooling system, but the regular service items for a long(ish) interval (WaPu, Timing/fan belt, clutch, exhaust/cat, alternator, seals) last roughly the same period.

The lower amount of waste heat a Diesel needs to deal with would be the bigger longevity factor - oil breaks down with heat, so the less heat your oil is exposed to the longer your oil protects the wear surfaces (journals, rings). Rubber parts, like timing belts, also age thermally.

But the biggest factors affecting engine life are how hard the driver flogs it, and if the engine in maintained properly.

56
it would seem to me that the internal combustion engine is at the end of it ́s development, you simply can ́t get the pistons to jiggly up and down in a better way, a bit here, a bit there maybe but at a cost of Godzillians. So what is next? Electric? A big and definitely maybe. You will need refined rare earths by the megaton and then, although an electric car is not fussy where it ́s electricity comes from, you still have to generate it somehow.

57
Well, the question was about RELIABILITY, not DURABILITY.

58
It's a myth to think that you can separate reliability from durability, specifically if you're trying to make that distinction based on fuel type alone.

The point still holds, petrol engines aren't less reliable than diesels because of the ignition system alone.

Reliability nowadays is mostly about sensor/wiring/software problems, and diesels are as prone to them as petrol.

Sensors, connectors and switches are all sourced from the same low bid suppliers, regardless of fuel source.

59
Well, Mazda has announced to build HCCI engines into commerically available vehicles by 2019... that's pretty soon for what I believe is the biggest change to how internal combustion engines work in... dunno... a century?

Basically a petrol engine that gets rid of the spark plug and ignites through pressure like a diesel - but to deal with cold starts and the like do they probably still pack an ignition system in it. In theory could this get you some 20-30% more efficiency (some American sources claim 50% but I believe thats mostly due to them being American...). Anyway: That's huge. I read somewhere that reducing the consumption of current petrol engines of a Golf sized car by a litre per 100km costs about 1 Billion EUR in Research and Development. If this engine works will it shake up those calculations on what's got the best footprint quite a bit.

60
You switch things around and try to counter-argument out of context.

Castro said "I always thought diesel engines were more reliable because they're built to withstand a much higher compression ratio."

Assuming he is talking about diesel engines in general and not only about newer ones, diesel engines do have a fame to be more reliable. This fame comes from the fact that they were simpler (in part) than gasoline engines. One reason is because they didn't have spark plugs-based ignition systems: old ignitions with distributors were known to be unreliable. Even modern ignition systems with coil-packs are not that much reliable.

Still, the argument was about whether diesel engines were/are more reliable because they are built to withstand much higher compression ratios, which is not the case.

PS: if you think RELIABILITY=DURABILITY, I hope you are not an engineer and don't have to develop products that need to be profitable.