Do cars exist that will do 700 miles at 70MPH on one tank of fuel?
Cornwall and back without stopping (other to drop my friend off) is something I do quite often. That's just over 700 miles round trip at say
80 MPH.
That's my point, for the school run etc, the exhaust will be emitting the most pollution.
By the time you get to the motorway the exhaust will be at its cleanest.
True. The very first diesel I drove was a Golf many years ago. It didn't have much pull. It was no match for my 1.8 petrol Golf.
Bu they've improved to the extent that I'd regard a turbo as an essential part of a diesel, whereas it's optional on a petrol unless you want shit-hot acceleration.
But for an even bigger example of gutless... I was loaned a Pug 2008 (the SUV-wannabe that's based on the 208) by the garage while my car was in for work. It had a 1.2 3-cylinder engine and it was major effort to get it moving from rest, and then engine throbbed and barked (yes, that's the best word to describe the noise it made) as I set off or when I accelerated out of a roundabout. The engine also ran at about 3,500-4000 rpm at a normal
60-70 mph which made it very noisy.OK, that was an exception: a heavy car with a *very* underpowered and therefore high-revving engine. But even a supposedly powerful car can suffer. Another garage loan car was a petrol Pug 306 with IIRC a 1.8 engine. Its 0-60 acceleration was superb - to the extent that I had to be careful not to overcook things when setting off at junctions. But on the motorway it was painful. It had virtually no 50-70 acceleration (I tried 5th, then 4th, then 3rd gear) and even in top the engine was screaming away. No match for my diesel 306 which didn't have quite the 0-60 but had considerably better
50-70 which is where it really matters on a long motorway journey where you may get stuck behind a slower vehicle and then need to accelerate hard to get past it when moving into a lane where other cars are wanting to do way above 70 and you want to overtake and then get back to Lane 2 as fast as possible.I wonder if manufacturers will ever develop a cat which can turn NOx (NO, NO2) into something less harmful. I think DPFs have reduced the amount of particulates, but it's the NOx that is the lingering problem for diesels.. I'm not sure what is is about compression-ignition that produces higher NOx than spark ignition. Maybe its simply that they are very lean burn, whereas petrol engines are stoichometric - they have an accurate petrol:air ratio rather than a great excess of air relative to fuel with diesel.
Next they'll be banning gas boilers. They are not far behind with their NOx emissions in city centres.
I can get onto my nearest motorway in 4 minutes ...
Are you built like a camel or do you have an attachment connected to your willy?
I?m pretty sure it?s just down to cylinder pressure and consequent combustion temperature.
Nitrogen is pretty inert but the hotter you heat it the more NOx you get, petrol or diesel. Diesels just have a bit of a head start on the combustion pressure/temperature.
That may be a factor too but I think it stems from the high cylinder temp primarily.
Tim
Yes. My Pug 308 1.6 HDi will do about 750 miles on a 60-litre tank at 70. The fuel economy is better at a steady 70 than at a variable 30-60 on single-carriageway roads. (OK, it's better still at a steady 50!).
I've never actually done 750 miles because I've always made sure I refuel while there's still a bit of fuel left in the tank. But I did a 700 mile journey (250 miles from old house to new one, then a break then 250 back to the old one, then part of the way back to the new house - while transporting things while we were moving house) and the trip computer was still estimating another 50 miles left in the tank. That was almost all on motorways or dual carriageways.
Ah, for some reason I'd always thought that diesel engines ran a lot cooler than petrol engines. Higher pressure but lower combustion temperature. Evidently not.
Can you not last 10 hours without a piss?
Hence why I don't understand why water injection for diesels has never taken off. I presume its not as simple as it may seem.
No-one said it was 700 miles non-stop. But it may be 700 miles with much shorter breaks than you'd need to allow for refuelling an electric car.
A petrol or diesel pump adds energy to the car at a phenomenal rate. Petrol and diesel are each about 35 MJ/litre
That''s a serious amount of electricity that you'd need to charge an electric car with to equal it. Even if the charging process was 99% efficient, that's still 70 kW of waste heat you've got to dispose of.
OK, it's not quite a fair comparison because electric motors are more efficient than petrol/diesel engines so you wouldn't need to take onboard as much energy. But it's still a lot of energy needed in a short period of time.
You may only need to do 100 miles in a day, with all night (or many hours during the day while you are at work) to recharge. But if you ever need to do a longer journey, you may have to re-plan your day if you have to factor in a recharge stop of maybe 6 hours somewhere in the day. Swappable batteries would be one way, but cars tend not to be designed with the batteries in an easy-to-remove tray and there's the age-old problem of swapping clapped-out batteries that don't hold as much charge for new ones which will hold more - I'm sure a comparable problem existed several centuries ago when stage coaches swapped horses several times on a journey: you may end up getting something much better (or worse) that you had before (leaving aside the short-term problem of tired horses that will be fine after a night's rest).
Only if I drink virtually nothing on the journey and for several hours beforehand.
I think the furthest I've driven without a stop was Southampton to York which is about 5 hours and I didn't have any coffee for breakfast and just a few sips of water on the journey. And I was glad to get to a loo at the end of the journey!
Water injection for diesels. That sounds intriguing. I'll have to look up what that's all about. I wonder if it needs a large amount of water in addition to the diesel fuel?
but who owned the stage coach horses?
But no particulates.
Think is if you walk past any queue of cars in London, you always smell a diesel or two. And many smoke if they accelerate moderately hard. Some older ones, a lot.
You have to remember the age of many on here. Prostates like footballs.
The evidence on health ri9sks hasnt chamged in 20 years.
What has changed is that cars are lasting too long and manufacturers benefit from enforced scrappage
they are more eficient so ythe actual engine block is likely to run cooler BUT not the combustion chanmber itself
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