Genuine question, not being facetious, Do the new euro4 engines cut down on particulates then?
Ok I accept that particulates are deadly, but I also ask to take into account the bigger picture, for exapmle
(1) all the toxic gases etc and impact on manufacturing the cars in the first place, with there now restrictive cost to fix, so more are scrapped earlier.
(2) As more cars are scrapped because of cost to fix, just think of the enviornmental impact of the parts of cost that cannot be recycled.
I feel that people 'overlook' the cost to the environment sometimes, for example, take the Prius, very environmentally friendly to run, but what to mancufacture and recycle? Even to recycle something takes energy and therefore must have an impact somewhere down the line?
Just to stress a point, Low energy light bulbs have mercury inside them, how toxic is this? And the costs involved in recycling or disposing of safely? So just think of ALL the environmental impacts, including those to peoples health of manufacture and then recycling?
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I would have thought the car manufacturers were aware of the side affects of DPF's and other Gizmo's that are used to pass euro 4 laws. Do they not have better soloutions then these filters, or can they not lobby Euro MP's to raise the issue, and work together for better technology? Surely it would be in their interest to do so....
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No matter what you did to a diesel it cannot be made as clean as petrol,for a start it weighs 20% more by volume although there has been a trend towards diesels it is now going the otherway in Germany as people realise its cheaper to run petrol cars.
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Andy, do you mean the diesel fuel weighs 20% more? Not really much of a factor in total car weight surely? Sure an iron diesel block is heavy as it has to withstand higher stresses, and the necessity of a turbo and high pressure injection means things are more complex than they used to be, but diesel still has an edge in some situations.
Diesel cars make a lot of sense for long distance motorway work, and are cheaper over high miles. I think people are realising that there are appropriate tools for jobs - in the same way that a Prius is a pretty stupid choice if mostly motorway work is intended, a diesel is not a good low mileage or predominantly city based role, *if* you are worried about local environmental factors.
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Present day taxation says its cheaper to run a petrol than a diesel in Germany even though its cheaper to buy per litre.You have to do all sorts to a diesel to make it reasonable clean and then it will not come near a petrol.
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I don't think it is all gloom and doom about diesels. The new Accord to be launched this year exceeds Euro vl emissions standards.
And when this motor arrives in production cars in the next three years, it will be able to provide even lower emissions and superior fuel consumption. Diesels traditionally produce less carbon dioxide than petrols ? but more nitrogen oxide (NOx). Yet the Super-Clean oil-burner has a clever catalytic converter that removes up to 99 per cent of the harmful emissions.
As a result, it combines the low CO2 output of a diesel with the reduced NOx outputs usually associated with a petrol motor
Taken from Auto Express.
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To address the subject of the thread, I would generally agree that Euro IV (Roman numbers for diesels, Arabic for petrols) engines and beyond now show too small a gain over their petrol fuelled counterparts to give a significant practical benefit in many operating cases.
This is a great pity as the diesel engine has many advantages over a petrol, primarily its ability to run non-stoichiometrically (ie run with a very lean mixture) and the absence of that mechanical abomination - the throttle plate. This is why the diesel is still the most efficient internal combustion prime mover and is of course the reason why everything you see around you was shifted by one.
I would never underestimate the importance of limiting particulate emissions, but as usual, the politicians have taken a steam hammer to the problem and killed the job. Given time, the diesel industry can develop ways of limiting particulates without the use of a crippling DPF.
As far as the comment about fuel goes, diesel fuel has a slightly higher density and a higher calorific value than that of petrol.
659. (Satisfied user of one of the last Cat III engines).
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This is a great pity as the diesel engine has many advantages over a petrol primarily its ability to run non-stoichiometrically (ie run with a very lean mixture) and the absence of that mechanical abomination - the throttle plate.
Petrol engines do not have to run stoichiometrically - that is only a requirement of the tranditional three-way catalyst. It is entirely possible to run petrol engines in a lean burn mode - as many are.
Many years back I did some consultancy work for Sonex on this theme. Bascially we monitored crank rpm and took the second derivative (i.e. rate of change of piston acceleration). This information effectively represents 'combustion quality' data. By setting a lower threshold you can lean out the mixture to some predetermined misfire limit and effectively use feedback control to vary the mixture so that the engine runs at the misfire limit (or close to it) under all driving conditions. The system was tried in some Ford Escorts to assess driveability - it worked reasonably well. With appropriate engine design its possible to go to very lean mixtures (50:1) and reduce throttle pumping losses.
Sonex are still in the business and have developed all sorts of emissions reduction technology - including Diesel systems which reduce particulates.
>>as usual the politicianshave taken a steam hammer to the problem and killed the job. Given time the diesel industry can develop ways of limiting particulates without the use of a crippling DPF.
The 'industry' has largely written the latest legislation (they usually get what they want in Europe - not so in the US and Japan!) - the politicians have just rubber stamped it. The VM's have had 20+ years to work on this problem. DPF's are a cheap and cheerful solution (for the manufacturer, if not the owner..).
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To AB: that all depends: there are several emissions from petrol engines that are greater than contemporary diesel; volatile organic compounds, benzene, CO, and for DI engines, ultra-fine particulates. At least the latest diesels are being treated for emissions. As for running and total costs, I can't say re Germany, but the ppm in the UK can be cheaper for diesel.
Edited by nortones2 on 31/01/2008 at 15:38
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IMHO, the worst emission from a diesel is the noise ;-)
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My last Mondeo was Euro IV compliant and did this without a DPF. So it's possible but of course CO2 emissions also now need to be cut.
As you'll know the difference between Euro III and IV was to reduce NOx and particulates. The Euro IV Mondeo did this by burning more fuel so the CO2 figure went up slightly and the mpg down.
My Mazda6 diesel does have a DPF and I now know that when it regenerates the DPF the car loses power for a brief moment. It was particularly bad a few times driving on the M40 on Tuesday and today... it felt a bit like someone had depressed the clutch. But being on cruise control I know that was not it.... so popped into Mazda dealership and they told me about the DPF thing. Hope they're right..... or could it be a dodgey clutch and they don't want to repair/fix it???? They even replace clutches damaged by drivers misuse upto 9000 miles apparently.
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I sometimes wonder if posts are always understood. Auto Express recently wrote about the new Honda Accord diesel engine that will exceed Euro VI emission standards with improved economy above the present diesel engine.
I'm satisfied with my iCTDI which returns over 38mpg on urban journeys, and 50mpg on runs, usually French autoroutes. If the new Honda diesel beats these figures, as Auto Express suggest, then I shall be well satisfied when I change my current model for the new one later in the year.
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Robbie, bear in mind that you are the lucky exception with your current Honda. I, and all others I have talked to, struggle to get more than 42 mpg even driving like a nun. Last tank, admittedly 4 up and heavily loaded on a trip to the lakes, I got 37.6 mpg.
Honda have admitted to me verbally that some Accord 2.2 diesels will get 50 mpg easily, most can't, and they've been unable to find what the difference is.
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Have you tried increasing tyre pressures?
I keep mine at the intermediate level. I can't remember the pressure, but it's the one with three up and same pressures all round. Road holding in the wet is fine, and there is no uneven wear on the tyres.
My consumption was poor initially.
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I've tried everything I can think of. The 43 mpg was with tyres at 35 psi (normally 33 all round) and a constant 65 mph on the motorway on cruise with the aircon off.
Normal use on a tank to tank basis is 40-41 mpg, that's driving normally with aircon on. Sadly as I've done 58k miles I'm not expecting any more bedding in, but I could be wrong.
Saying that, I wasn't expecting to have intermittent loss of power that they can't trace either, but that's another story.
Edited by Gordon M on 31/01/2008 at 18:41
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I've tried everything I can think of. The 43 mpg was with tyres at 35 psi (normally 33 all round) and a constant 65 mph on the motorway on cruise with the aircon off.
Wow that is poor. Measured over a decent distance presumably?
As a comparison of 2.2 diesels, that sort of cruising speed in my Avensis gets 55-60mpg, with both air-con and cruise on. I've never switched the air-con off in 16 months/25k miles, and only two or three times have I got less than 45mpg on a tankful. The usual mpg on a tankful is closer to 50, on 60% Mway/40% urban driving.
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It was a 320 mile round trip, so probably about 15 miles of that wasn't on the motorway.
To be fair, over about 5k miles I got 41.3 mpg from completely normal use, with no effort to conserve fuel, aircon on and 'brisk' progress on the motorway. I've never had a car with fuel economy less sensitive to how you drive it.
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I've never had a car with fuel economy less sensitive to how you drive it.
That is strange isn't it? Saves you worrying about putting your foot down occasionally anyway!
The Avensis has a good 10mpg (ie 20%) variation depending on roads, right foot, temperature, head-wind!! Even a service and new front tyres seemed to knock 5mpg off... 'tis a very sensitive car, although never unreasonably thirsty obviously.
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My Ibizas EU4 compliant without DPF as far as I know. And it still smokes a lot when you boot it.
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I deliberately opted for the Euro III Scenic because I didn't want the FAP system. I read an article that said that BMW investigated the same system and ditched it because they couldn't make it reliable. Certainly from talking to Renault owners with FAP on their cars, they are constantly being told their driving patterns are incompatible with the system, and that there's nothing that can be done about the repeated error messages, intermittently gutless performance, and fuel economy that's about 5 mpg heavier than mine with the same engine.
As far as I am concerned, even without all that it's just one more thing to go wrong as the car gets older, and in any case even in Euro III guise it's very clean running. I followed SWMBO home once and she was pressing on. The thing doesn't smoke any way. The tiniest hint of a puff for maybe 0.5 of a second when you first boot it, but nothing after that.
Cheers
DP
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I think DP's post just proved that Renault are us at designing and making diesel engines. History proves it.
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I don't know what you meant by that madf, but I'm guessing it wasn't a complement.
Cheers
DP
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The harmful effects of particulate matter have been known for decades. To some extent the car makers (in Europe at least) have been living on borrowed time. Legislation has been delayed and delayed - largely due to the strong motor industry lobby in the EU (which is why our emissions legislation has always run well behind e.g. US and Japan).
The legislating committees are stuffed full of car industry reps; they largely set the framework of the regulations.
Eu emission legislation does not specify the application of any particular technology, it just specifies emissions limits. DPF is one (fairly cheap) solution - but there are others.
Getting Diesel fuel to burn cleanly and smoothly under all circumstances is a tricky business, which is why the engines end up so complex.
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The ultra-fine fraction (UFP) are suspected in the association between cardiac illness and vehicle emissions, certainly. But UFP are not confined to diesels, as lean-burn gasoline DI engines and CNG give rise to UFP, possibly from engine oil in the latter. They also derive from natural sources. Most air pollution measurements have focussed on the PM10 particles, as the technology has been limited until recently. Its thought now cardiac inflammation risk comes from PM <2.5 and nano-particles. Measuring the mass of PM10 has been commonplace but UFP contribute little mass to PM10 or PM2.5, although the numbers of UFP are relatively large. The Americans have seized on diesel, but gasoline is not yet required to control UFP: wonder why? Pointer here: www-g.eng.cam.ac.uk/mmg/environmental/collings.html
BTW, I am no expert on epidemiology but take an interest, due to previous health-related work.
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I don't know what you meant by that madf but I'm guessing it wasn't a complement.
OK saw your knock of Renault diesels in the other thread, so I guessed correctly ;-)
madf, Euro IV compliance has caused economy and driveability issues across the board due to the complex systems introduced to meet this standard. In any case, since when has a problem with an exhaust particulate filtering system been an engine issue? Even the finest engine in the world will all run rough when confronted with a blocked exhaust.
I have seen nothing to convince me that problems with Renault dCi engines are any more common than injection problems on a Ford TDCi, turbo failure and swirl flap ingestion on a BMW x20d, poor economy and power loss on a Honda CTDi, MAF, head gasket and plastic water pump impeller failures on various VW TDIs etc etc. Yet we all know more people with each of these cars who are delighted, than those who have had problems.
The "big" Renault problem - turbo failures on the early F9Q 1.9 was fixed four years ago now, and the majority of customers affected were seen alright by Renault. They acted late yes, but they did act, and modified the design of the turbo and EGR valve. BMW addressed their turbo issue too, but cars are still leaving the factory with those plastic swirl flaps in the manifold. So are all BMW diesels useless? Of course not. Will the significant majority do 200,000 miles without failing? If I were forced to bet a year's salary one way or t'other, I wouldn't bet against it.
I'm guessing you've had a bad experience somewhere along the line, but that has little relevance in the wider world of Renault diesel ownership. I had a shocking, disgustingly appallingly unreliable VW, but for every one of me there are probably 10 with the same car who have had no major problems and who would happily buy another. I ranted and raved about that car, and abused VW to the point of needing to consult my copy of Rogers Profanisaurus for new ideas, but four years on if a VW I liked came up at the right price, I'd buy one.
Cheers
DP
Edited by DP on 01/02/2008 at 12:47
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Honda have admitted to me verbally that some Accord 2.2 diesels will get 50 mpg easily most can't and they've been unable to find what the difference is.
I have heard this about the Honda engine from my brother in law who has an FRV. It is very quiet and refined, but struggles with fuel consumption. I have the same situation with my 2.0 TDI A4, mine has to be treated with kid-gloves to ger early 40's mpg, whilst other idential cars seem to easliy achieve the elusive 50mpg.
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Interesting to read that the Honda diesel isn't sensitive to the way it's driven - the results seem uniformly mediocre for a 2.2.
I didn't realise that VAG engines varied betwen diferent cars as much as that. I know that mine (a 2.0 TDI like Roly93's) varies considerably according to the way it's driven - 10 mpg. If I want to press on and use the (considerable) acceleration to the full, I'll get 45-50 mpg; a gentle right foot will yield 55-60.
I'm not complaining - it's nice to have the choice.
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My VAG pd engines the same- 1.4 tdi that if your gentle will easily top 60mpg, if your pressing on even a bit goes down to about 48 mpg.
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I will be interested to see how my new co. car, a Mondeo IV 2.0 TDCi manual (with DPF and all the anti-emissions gubbins), will compare with my outgoing B5.5 Passat PD130, which is largely unencumbered.
The Mondy is bigger & heavier so I'm not expecting the same economy, but I am keen to see just how big the difference is.
I'll be sure to post experiences & figures as I get them.
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Is it my imagination, or do more people complain about the fuel consumption of their Hondas - especially diesels - than most other makes.
Whenever I have taken a test drive in a Honda, they always seem undergeared. Perhaps I have hit on the reason for the poor fuel figures.
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I havent been following this thread closely though I dont think it is Euro IV that handicaps diesels much over Euro III, rather DPFs might be the issue.
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Is it my imagination or do more people complain about the fuel consumption of their Hondas - especially diesels - than most other makes.
I think with the diesels it's because most people buy them expecting to get the 50+ mpg that the official figures and 90% of the road tests have achieved. And most people only get 41. I wouldn't mind, but some (Robbie for example) DO get the 50+, so it's clearly possible on some examples.
Whenever I have taken a test drive in a Honda they always seem undergeared. Perhaps I have hit on the reason for the poor fuel figures.
I don't think so, in 5th at 70 the car is only doing about 2100 rpm, so I wouldn't expect that to be an issue.
Saying that, the VTEC in the petrol does enable the car to go quicker by enabling it to use more fuel, so if you rev it hard....
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