CD Article: 2007 Mercedes-Benz E320 Bluetec

[CD_Editor]

You may discuss our cover story of the day in this thread....
First Drive:


Now that Ultra Low Sulphur diesel fuel is available at the pumps, Mercedes-Benz' new Bluetec technology allows the company's 3.0-litre Bluetec diesel V6 to meet the strictest emissions standards in North America.  "Emissions aside though, the E320 Bluetec sedan's abundant torque, quiet diesel engine, excellent fuel economy, and long driving range is what's likely to seduce buyers into switching to diesel," says Editor, Greg Wilson.   More...

[scottmcphee]

Nice guts, shame about the face.
Now lets see MB wrap some sexy metal around that street pounding engine! 

Scott

[tpl]

Why ?   Maybe making the awd and especially the awd wagon with Bluetec would be interesting, if expensive, but the basic car is IMHO quite attractive for what it professes to be; a 5 seat luxury sedan.

I do think that it will be a big seller.  Diehard M-B diesel fans will want to get one of these BEFORE the next model year when they have to fiddle around with adding dilute urine to it every so often.Or, if the EPA decides not to accept the adding of the solution, no more M-B diesels for a bit longer.

If it was a bit cheaper, say $60,000 including leather, rather than $70k   I'd be tempted even though i HATE automatic transmissions. Even better if they put the engine ( or a smaller version of it )into a C-class wagon...

[Loudpedal]

Auto manufacturers need to warranty the emission control equipment for 10 years right?   

I just had a flashback to another thread about used Mercedes Benz vehilcles requiring expensive servicing...

[Jameel]

I wonder if this will ever filter down into the Chrysler products (beside the Cherokee)?

[scottmcphee]

But it's so Kia Amanti 2004 looking.

[articsteve]

Though the AdBlue system requires AdBlue fluid to be replaced at regular intervals (it uses about one litre per 1000 km) Weber indicated this could be done during regular service intervals at the dealership.

That's a bit vague don't ya think 

What's a regular service interval?  12,000 km?  That would require a 12 litre holding tank.  How much is this Adblue $$$$?

[tpl]

That is a worry and... the stuff has to still be a liquid at -30 or so if they are to sell these things all over Canada.  So I wonder what else is in it apart from the ammonia.

I'd rather see a smaller reservoir, maybe same size as a washer fluid one 4-6 litres and the stuff available at every gas bar.  OR for Canada to just stick with the new 2007 standards for diesels for a few years.

[banfield]

Would have been nice if this article had included estimated exhaust system service costs.  Judging from the description of the very complex exhaust system components and controls, need for a special additive and even special engine oil (also see Jim Kerr's article on this system elsewhere on the website), maintenance costs could be prohibitive.  1000 km or so per tank of fuel sounds great, but what if the cost of maintenance eats up all the fuel savings? And of course, the initial cost of the system will be reflected in the high price of the vehicle.

[tpl]

I doubt that the availability of the engine oil will be a problem... Shell, Mobil, Amsoil Valvoline all claim to have a CJ-4 oil available... but some of them say it will be more expensive by 10-15% than the CI-4 oils it replaces. However, these oils are not the sort of thing that every crappy tire has on the shelf !

[Titanium48]

It sounds like "AdBlue" is a urea solution.  Urea is relatively cheap (the solution shouldn't be much more expensive than diesel on a per-litre basis) but it does like to crystallize/freeze at -11°C.  Replacing some of the urea with organic ammonium salts can lower this to ~-30°C though.  When urea is injected into the exhaust stream just before the SCR catalyst it decomposes into CO2 and ammonia.  The ammonia is a reductant which allows the catalyst to convert NOx to nitrogen (the ammonia is oxidised to nitrogen in the process). 

The system works, but unfortunately the real solution to the diesel NOx problem hasn't been invented yet.  Direct decomposition of NOx to nitrogen and oxygen is an energetically favorable reaction and is thus theoretically possible, but no suitable catalyst has yet been developed.

[scottmcphee]

..well if you're stuck at the side of the road and need to fill up the exhaust emissions tank with urea to get going... I know a cheap and ready source for that.  I wonder if it would work.. dilute solution...  Not AdBlue.. Add Yellow.  I think the Germans may have finally come up with a plan for second hand beer!  Miles-per-case.  Wouldn't that be the ultimate next-gen fuel, step aside Hydrogen.

[Titanium48]

...Your new Mercedes comes with a full set of catheters for those long road trips with the family...

It would work to some extent, but you'd need 10 times as much as the urea concentration in "second hand beer" is only about 3% (less if the beer is consumed too fast), compared with about 30% in the real solution.  The salts would corrode your exhaust system and might deactivate the catalyst though.

[tpl]

The whole AdBlue(™) thing seems like a patch up job to me.   Apart from the EPA  wanting to have all vehicles obeying one standard  is the saving of the amount of NOx from a few '000 expensive diesel M-Bs going to save the planet ?

[Titanium48]

It is a patch up job, but unfortunately adding exogenous reductant is the only currently available way of scrubbing NOx emissions under lean conditions.  Using extra fuel as the reductant has also been investigated, but it is much less efficient and would negate the fuel economy advantage of the diesel engine.  Until a true NOx decomposition catalyst is invented we will have to make due with SCR if we want clean diesel engines.

[tpl]

Ok. I must admit that I thought that research such as finding a catalyst for a particular reaction that is know to be catalysable  was just a question of using a computer model of the reaction nowadyas and that the real work was in making the catalyst  into an engineering practicallity.

Like trying to make these high temp superconductors into practical means to transmit power rather than fragile laboratory curiosities.

[Titanium48]

Chemistry is still largely an empirical, trial and error science, but there are some promising leads for NOx decomposition catalysts.   Certain copper containing zeolites (aka molecular seives, relatively inexpensive and commonly used in the chemical industry) have shown good NOx decomposition activity under laboratory conditions.  Hopefully the engineers will find a way to make them efficient and durable enough for real world use.

[soj]

The whole AdBlue(™) thing seems like a patch up job to me.   Apart from the EPA  wanting to have all vehicles obeying one standard  is the saving of the amount of NOx from a few '000 expensive diesel M-Bs going to save the planet ?

No it isn't but that's not the US EPA's concern.  As fuel costs rise, the trend that has already occurred in Europe will start to happen here.  There one out of every two new cars sold is a diesel apparently.  If we in NA even reach the 1 in 5 or 1 in 4 market penetration level, air quality in most urban centres will be the worse for it unless you set some pretty stringent emission controls. 

[soj]

On an other note, I wonder what all this marvelously complex emission technology will do for the E class' already abysmal reliability ratings?

[tpl]

The whole AdBlue(™) thing seems like a patch up job to me.   Apart from the EPA  wanting to have all vehicles obeying one standard  is the saving of the amount of NOx from a few '000 expensive diesel M-Bs going to save the planet ?

No it isn't but that's not the US EPA's concern.  As fuel costs rise, the trend that has already occurred in Europe will start to happen here.  There one out of every two new cars sold is a diesel apparently.  If we in NA even reach the 1 in 5 or 1 in 4 market penetration level, air quality in most urban centres will be the worse for it unless you set some pretty stringent emission controls. 

I am sure you are correct.

 However, if those zillion people who are now driving older cars trade up to a Bluetec diesel ( or equivalent technology), their older , but still clean, cars on resale will cause a zillion really old clunkers to be scrapped which should improve air quality.  I know that is a trickle down theory of emissions but I recall the EPA chief techy saying a year or two back that its the oldest 20% of cars cause 90% of the emissions.   The diesels also produce less CO2 than gas engined cars which people believe is a good thing as well as the absolute smaller amount of oil used.