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2002 FIAT Marea estate, now has 330k on the clock.
Has averaged 5.5 l/100km week in week out for the last four years and 130,000km - 51.4mpg in old money. Long and short journeys, no problems apart from needing a new alternator for its 245,000km birthday.
I do use Firestone fuel-saver tyres and run on premium diesel though.
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I am running a 407 sw 1.6hdi round Germany at the moment and its doing better than the manufacturers figures by far..Having driven a new Prius for two days it was horrible no power, heavy on fuel and expensive if you were daft enough to buy one ,
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Decent around town and short jouneys-pointless elsewhere. It amuses me that people think of hybrids as 'smart' or 'intelligent' technology; little realising that an electric motor is only as efficient as the source of the electricity-in this case a bog standard petrol engine-plus all the losses from converting mechanical motion into chemical energy, into electrical energy, back into mechanical motion.
Even worse is the diesel hybrid concept. As any fule kno, diesels are efficient even at low load. You can't make the same efficiency gain twice.
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Er, actually the majority of the electricity that a Prius uses is either scavenged from the electrodynamic braking system while slowing down / stopping or taken while the engine's producing more power than is strictly required for what the car's doing, allowing the engine to run at a more efficient speed without wasting its output.
Or, in other words, the vast majority of it's electrical energy is what you would waste anyway in conventional vehicles. The loss of efficiency you refer to only becomes a factor in the rare occurance that it runs the engine specifically to charge the battery.
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Er, actually the majority of the electricity that a Prius uses is either scavenged from the electrodynamic braking system while slowing down...
In all but the most incompetent drivers, regenerative braking contributes very little to battery charge.
Keeping the engine loaded above what is required for road load does improve efficiency-but you still have non-negligible losses in charging and discharging battery that partially negate this.
A typical diesel engine is ~40% at full load
~ >30% at only 25% load
Pious engine ~35% efficient at full load, and falling away below that as throttled petrol engines do. So really a pious only achieves what a Diesel does except with a ghastly CVT transmission and a more convoluted electromechanical system. So yes I do understand how the concept works. Because I can see through the marketing fog and make a direct comparison. There's nothing spectacular about hybrids outside of stop-start driving. Period.
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Er, actually the majority of the electricity that a Prius uses is either scavenged from the electrodynamic braking system while slowing down...
In all but the most incompetent drivers, regenerative braking contributes very little to battery charge.
It would be interesting to compare brake-pad life with a conventional car - assuming similar driving style and usage.
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Can't remember the last time I changed the pads-it was over 3 years (30,000 miles ago). Good drivers don't brake that that much-even in urban traffic. Nothing will help drivers who immediately switch from throttle to brake-even with regenerative braking (conventional brakes kick in under heavy braking).
The Pious has some good points
-it is unbeatable in stop/start traffic -It's NOx/PM emissions are a lot lower than diesel
-Insulated coolant reservoir for fast warm up (why don't conventional engines use this??)
I haven't driven one-but I have been a passenger in one. It was fine albeit only averagely economical on the 50 mile cross country trip we went on. Personally I like the sound of a diesel in preference to the milk-float like whirr of electric motors. I also prefer proper cogs in the drivetrain-and a clutch. The detached driving experience of the hybrid is the biggest turn off-and its exaggerated claim to intelligence and efficiency.
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I quite fancy trying the diesel-hybrid idea that all the manufacturers seem to be adopting now, where you have a conventional turbo diesel drivetrain driving the front wheels and a smaller electric motor and battery pack integrated into the back axle.
The idea seems to be to use the electric motor in assistive mode, to help overcome intertia from rest, then the conventional drivetrain takes over at about 15mph.
The ECU supposedly sorts out how much assistance is needed and when, etc. The Peugeot iteration is switchable, apparently, so you can vary the amount of assistance.
Edited by craig-pd130 on 19/05/2011 at 16:41
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I quite fancy trying the diesel-hybrid idea that all the manufacturers seem to be adopting now
A lot of diesel engineers (including me) regard the Peugeot diesel hybrid as a publicity stunt. The assumption people make is that because a hybrid might improve the fuel economy of a petrol by ~25%, it will also improve the efficiency of a diesel by ~25%. It won't for reasons I've outlined above. The diesel has already made the efficiency gains at low load, and the same gain cannot be made twice. An electric motor cannot be more efficient than it's source of power. There's a reason that automotive engineers have been wisely ignoring the non-engineers clamouring for diesel hybrids from day one.
Edited by unthrottled on 19/05/2011 at 20:47
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I'm not sure that's comparing apples with apples. There's no mechanical connection between the diesel motor and the electric motor: only an electrical one.
If, when accelerating from rest, the electric motor gives a shove to get the car rolling -- even if only up to 10 or 15mph -- it will require less effort from the diesel engine, which means less fuel used.
The batteries can be recharged from the alternator and the state of charge managed by the ECU so it doesn't get dangerously low.
Sure, this will sap a little power from the engine compared with, say, an ultra-modern clutched alternator.
However, it's just my speculation at the moment. I think it's an interesting idea, but of course the proof will be when these cars are available and can be tested side-by-side with their conventional equivalents.
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If, when accelerating from rest, the electric motor gives a shove to get the car rolling -- even if only up to 10 or 15mph -- it will require less effort from the diesel engine, which means less fuel used.
No! The electric motor is charged either directly or indirectly via the diesel engine. The alternator is a parasitic load on the engine. You only get back what you put in-minus all the irreversible losses incurred by changing energy from one form to another-and back again.
The only reason the hybrid works for petrol is because low load efficiency is poor-with a diesel it isn't and you can't make the saving twice.
Hybridising doesn't even help with downsizing. The minimum useful cylinder capacity for a diesel is ~400cc. Below that, the volume/surface area is just too poor to be useful. The minimum number of cylinders required for acceptable smoothness is 4. That gives the smallest practical diesel engine of ~1600cc-which tends to be the asymptote that most manufacturers have already arrived at.
Like I said, there's no technical difficulty in hybridising a diesel; what holds it back is that it is a rotten idea.
Edited by unthrottled on 19/05/2011 at 22:43
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I agree the alternator is a parasitic load -- but with modern, smart, clutched alternators, it doesn't have to be engaged all the time. It could be managed so that it does its heaviest work when the diesel engine is on the overrun, for example.
Of course you don't get something for nothing, but it will be interesting to see if this kind of "assistive" hybrid will live up to manufacturer's hopes and claims.
As I said in an earlier post, the proof will be in the road-testing. As we've seen in several road tests over recent years, Honda and Toyota petrol hybrids are no more economical (and often, less so) when compared against a fairly conventional diesel hatch in real-world, give-and-take motoring. I'm keen to see how these upcoming cars will fare.
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I used to get over 50 mpg (log kept) when I ran Audi and Passat diesels. But I don't do 20,000 year any more and my diesels (completely reliable) were rather old-school, So, for those who don't want DPF DMF because they have to pay for fixing the faults, or those who are doing fewer longer runs, the Prius etc have an advantage over other petrol engined cars. I suspect there will be quite a segment who do not want diesel at any price. I like them: just don't want one!
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Can't remember the last time I changed the pads-it was over 3 years (30,000 miles ago). Good drivers don't brake that that much-even in urban traffic.se this??)
Indeed, I've done 70K miles on my current set of pads and there's plenty of meat left.
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>In all but the most incompetent drivers, regenerative braking contributes very little to battery charge.
Precisely the opposite IMHO! The incompetant driver would be the one jumping on the anchors at the last minute, forcing the use of the friction brakes to scrub off the majority of the speed. Decelerating gradually with a light touch on the brake pedal causes most, if not all, all the braking effect to be electrodynamic. Remember here that retardation on overrun (the province of engine braking in conventional vehicles) is a purely electrodynamic effect in the Prius.
This is very easy to prove in a Prius. Start at the top of a decent length hill with a depleted battery. Remove foot from throttle. Govern descent speed with brake pedal. The engine will remain stopped throughout and the battery will very likely be fully charged by the time you reach the bottom. There's a downhill-to-junction motorway exit down the way from me that can get it from "two bars" to full in under a kilometer doing this, scrubbing off 120kph downhill all the way (a sight faster than the engine ever does it directly, blowing your first point clean out of the water). Before you ask where that 120kph orginally came from, the answer is same place yours did, the engine. The difference here is that we both have to stop at the junction and the Prius turned it back into something useful, while you warmed your brake pads and the surrounding atmosphere up.
Apparently, according to stuff I've seen reported elsewhere (possibly apocryphal), the truly economy fixated manage to get their discs to rust through disuse. I don't even try, 'cos I don't care. It's purely a tax thing and it comes with a fuel card. Fun to work out how it works though.
I take it you've never actually driven one?
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No. I've been a passenger in one and on a 50 mile journey @~50mphwith 3 people on board, it averaged 49mpg-pretty average. Admittedly this sort of driving is not its forte, but it does highlight the ineffectiveness of the hybrid system in steady(ish) state driving.
This is very easy to prove in a Prius. Start at the top of a decent length hill with a depleted battery. Remove foot from throttle. Govern descent speed with brake pedal. The engine will remain stopped throughout and the battery will very likely be fully charged by the time you reach the bottom.
Unless it was a steep hill, and the speed very low, you won't get very far before air drag slows you down to an unsustainable speed. It's less efficient tthan knocking a normal car into neutral and coasting as far as possible-or, over short distances, leave the engine in overrun and use no fuel.
If you read the road ahead only about 10% of your fuel should end up being dissipated through the brakes-even in town. Regenerative braking might recuperate half of that-5% improvement in economy. Yay. Regenerative braking is admitted by most to be a bit of a gimmick.
Edited by unthrottled on 19/05/2011 at 20:38
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I am running a 407 sw 1.6hdi round Germany at the moment and its doing better than the manufacturers figures by far..Having driven a new Prius for two days it was horrible no power, heavy on fuel and expensive if you were daft enough to buy one ,
Totally agree, why on earth do people consider that hybrids are green ?? They are less economical than equivalentg sized modern diesels and use a lot more scarce raw materials in their construction - batteries motors electronics etc, and must also require more energy to construct in the first place because of their added complexity. Also, I would guess that MPG raises as the battery starts to get tired, just like a middle-aged laptop.
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@WellKnownSid -- that's impressive, which engine do you have in that? Excellent value motoring.
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The 1.9 JTD. Car was five years old when I got it, and already had 200k+ on the clock which probably did more good than anything... well run in!
It gets an oil change every 10,000km which is half the recommended figure, and I'm obsessive about major service items if failure mode is catastrophic (cam belt, tensioners, water pump, thermostat and coolant all changed last year).
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My 2010 Nissan Note 1.6 Petrol Automatic is getting the equivalent of 60mpg ...on LPG.
Plus it too has 'None of the problems associated with Diesels' as it isn't one,
I do 20K miles a year so LPG works very well for me.
Filled up today.. 33.2mpg on LPG with the price difference thats an equivalent to 59.84
Best I've had..driving really carefully 63mpg, worst 55 mpg. I sure do miss that Turbo Diesel kick in the back though. Personally I will never EVER buy a hybrid, if I couldn't get LPG I'd go back to a super efficient Turbo Diesel.
Edited by Ethan Edwards on 19/05/2011 at 00:26
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The company I worked for started to lease these specifically for the service guys to get into and around the London congestion zone. Admired rather than liked I think, but they seem to do the job. The load space is compromised by the sloping tailgate and high load floor and I witnessed daily attempts to fit equipment and boxes into them that a van or estate would have taken easily. Most sport roof racks.
I have only been driven in one and was surprised by the performance. No turbo-diesel kick in the back, but a controlled acceleration that got you to speed quite swiftly. The drive train is supremely quiet at low speed and in traffic, but gets very “busy” at motorway speeds if you are trying to keep up with the rep-mobiles on the outside lane. It all runs out of puff at about 90mph. With two up and the load space full of gear, performance tailed off up motorway inclines.
Economy? The fuel gauge didn’t move off the full position, even though we drove about 80 miles to our destination. A bit optimistic I think. My driver turned off the distracting information graphics display, which may have given a more realistic reading. When you aren’t paying for the petrol, you don’t need to know.
Clearly a good part of the economy of these is the computer controlled acceleration, smoothing out the driver input and calculating the best drive combination to achieve its performance. This probably explains the lukewarm response from some drivers used to the instant response of a modern TD. It’s all just a bit too sedate for them.
From a passenger point of view however, smooth and comfortable.
Would I buy one? The load carrying ability of the Prius package would be a problem for me and I would need to convince myself of the real world economy, but if we are all forced back to petrol by legislation, this Toyota solution has to be worth a look. I would not be put off by negative comments from those who have never driven one or who have not researched how the concept works.
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A local Toyata rep was trying to sell me one about a year ago.
I asked him how much a towbar was.
He looked blank......that was not an option.
I then reminded him that I had come in looking for a diesel.
Salesmen
Huh!
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It's load space that puts me off the Prius. Even with the high load floor (presumably the batteries have to go somewhere), I would have thought that an estate version would sell like electric cakes ...
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I think the space inside and the price would put me off. The theoretical 3.9l/100km of the Prius sounds pretty good - 72mpg, but a Skoda Octavia Greenline II hatchback does slightly better at 3.8l/100km combined... 74mpg, and costs at least 20% less.
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I think most, who haven't driven one in it's designed environment, are missing the point with Prius.
It's as comfortable, smooth, quiet, refined and pleasant to drive or ride in as a top range executive automatic petrol. it's uncannily quiet and smooth at normal urban speed. With the running costs of a hatchback to boot, especially in the urban environemt when it trounces everything except a motorised shoe.
Prius isn't just about economy, though agreed that load space could be better, hopefully that will be addressed in the forthcoming MPV version.
In the urban crawl, all but the best proper automatic gearbox Diesels are nothing short of horrible to drive, noisy to boot, especially at tickover which the Prius doesn't often and if it does is barely audible and vibration isn't transmitted to the cabin.
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Toyota release the Prius+ next year, a seven-seater MPV version which should meet load space needs (unless all 7 seats are up).
We should always remember that the Prius is a car targeted specifically at our diesel-dodging friends in the good old US of A, where it's gone down an absolute storm.
Had the London CC charge not existed, I sometimes wonder if it would've ever taken hold over here at all.
That said, smooth, quiet hatchback/mid-size petrol automatics are few and far between. I think the Prius gets a fair few sales simpy because of the way it drives, it's such a reserved, quiet, seamless progression. Fairly unique in this car sector, with good economy being a nice bonus. Toyota's 5yr manufacturer warranty is another factor too.
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Having Googled a bit on the new MPV Prius, it doesn't look as though it's going to have much more load space than the original. Estate cars should be big, square, and be capable of taking a wardrobe (plus another on the roof rack).
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The Mazda 5 7 seater is the Prius+'s (MPV) nearest competition. It has 1485 liters of capacity with the seats down.
The Prius+ has 1900 litres with the seats down. So it would seem it is very good.
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>The theoretical 3.9l/100km of the Prius sounds pretty good
"Theoretical" is the operative word! I reckon to average about 5.6ish in summer and 6.1ish in winter. It has to keep the cat and heater warm, so runs the engine more in winter. Also the winter boots have a higher rolling resistance than the super-economic (but useless in the cold) standard fit ones.
Then again, I'm not trying as it's a fleet vehicle and comes with a fuel card. (As a dyed-in-the-wool diesel-hater it was the only option, the 300EUR pcm tax break was a bonus.) You can take those figures as "what you get if you cane it" ones.
Good things: Interior space (like the Tardis), there's loads underfloor in the back too. Flat load space with seats folded. Storage bins everywhere. Quiet, ridiculously so on electrics. Possibly the easiest thing to drive there is - most relaxing. Loads of odd toys to play with. Rear camera with parking cue lines. Reliable. Cheap to service. Satnav good, fast and accurate. Even basic ICE system plays digital files, saving disc swapping.
Bad things: High loading sill at the back. No possibility of towbar. A tad underpowered (the new version fixes this I believe). Autopark is gimmick-demo-in-pub-carpark only (but you have to have it to get the camera). Road noise on standard tyres. Lever adjust seat back rather than wheel (again, new version??). Choice of "sit bolt upright" or "lumbar pain" driving positions only. Steering wheel has rake only adjustment. Little 12v aux battery tends to expire as it never gets a proper charge/discharge cycle. Space saver spare. Climate control not as good as some. Engine noise intrusive over 150kph on the Autobahn....;-)
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The Skoda Octavia Greenline is slower than the Prius 10 secs to 60mph vs 12 secs. Load capacity is similar (580 vs 550 L).
With the price of diesel being higher than petrol, 72mpg vs 74mpg isn't going to work that much different overall.
The Prius also has the advantage of being quieter and probably cheaper to service.
The Skoda is at least 3K cheaper than the Prius, but the depreciation is higher on the Skoda.
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