Reason for US diesel delay

Excerpt from BBC interview with Tokio Ishino, staff manager for powertrain development at Mazda:

In the Mazda 6, Ishino explained, a low compression ratio allows perfect ignition timing. Combustion only happens when fuel and air are fully mixed in the chamber before they ignite. There are consequently no oxygen deficiencies and no fuel hotspots the factors that, respectively, cause NOx and soot. Optimised combustion means the Mazda 6 would meet US particulate-emissions regulations without filters. The engine is, quite simply, clean.

In normal diesel engines, Ishino said, a higher compression ratio is needed for cold-weather starts and to ensure smooth operation as they warm up. Mazdas Skyactiv-D cures this with ceramic glow plugs to start it up and variable exhaust valve lift, which allows hot exhaust gases to circulate and warm the engine more quickly.

The difficulty, and frankly, the delay for US sales relates to the quality of the fuel. The cetane number is low, which means the fuel itself has less ability to auto-ignite, Ishino said. The challenge for Mazda is to ensure the engine starts up without difficulty and still controls soot and NOx in such conditions, because the diesel formulation in the US will not change for the sake of accommodating a clever engine

This has required additional development, Ishino added. That is why Americans can currently buy a 2.5-litre gasoline Mazda 6, but not a 2.2-litre diesel. But it is on the way, scheduled to arrive in the second half of 2013 for the 2014 model year again, with no additional NOx aftertreatment. It will burn fuel as cleanly in the US as it does in Europe.

Full article at: http://www.bbc.com/autos/story/20130...iesel-invasion

Makes sense. North America should really improve on the diesel they import.

Thanks for sharing.

Link isn't working for me.

I know Volkswagen is having significant problems with the high pressure fuel pump in their USA TDI diesel engines, due to the lower lubrication properties of typical American diesel fuel.

Seems as though all car companies have to re-engineer their diesel engines for their American vehicles.

Interesting info, (especially since the source is a staff manager for powertrain development at Mazda).

A clean diesel, with no additional aftertreatment is a technical challenge, and not cheap.

Full link: http://www.bbc.com/autos/story/20130131-mazda-prepares-us-diesel-invasion

Note: to clarify the first line (bolded) in article, this engine still has a costly DPF.

I have read about this before...

I'm no expert on refining, but the poorer quality has to do with continually intensifying emissions based mandates and regulation by The Fed. This is compounded by inadequate infrastructure at the refining level. It takes time to engineer, implement and build refining upgrades which can improve diesel quality and capacity. But, improvements are being made. For example, the company I work for recently completed a multi-billion dollar upgrade to their Port Arthur refinery, making it the largest output capacity refinery in the US. With the expansion, output doubled, along with improving the capability to process virtually any quality of crude oil.

The weird thing is, lubricity can be improved (what I believe it lost in stringent refining), with additive injection. Lubricity additives are injected at the distribution level, which is where I work. I'm not sure why if lubricity is poorer in the states, they don't just up the additive injection rates. The lowest allowable concentration of lubricity additives is generally quite low.

After reading this thread I am no longer as disappointed as I previously was with not owning a diesel. If all the manufacturers are having a difficulty with American Diesel, then I would be hesitant to buy a diesel-powered import car, and I certainly wouldnt want to be among the first adopters.
Perhaps the US will benefit from the delay since the 2.2 diesel is out everywhere else and they have had a chance to observe long term performance of the engines and refine the tuning for the US market.

IHeartGroceries said:

I have read about this before...

I'm no expert on refining, but the poorer quality has to do with continually intensifying emissions based mandates and regulation by The Fed.

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You have been misinformed. The poorer quality of US diesel has to do with oil company and domestic auto/truck maker lobbyists. If the US would adopt the cleaner Euro spec we would get the same clean diesel that they get and diesels could be imported to the US without modification.

The weird thing is, lubricity can be improved (what I believe it lost in stringent refining), with additive injection. Lubricity additives are injected at the distribution level, which is where I work. I'm not sure why if lubricity is poorer in the states, they don't just up the additive injection rates. The lowest allowable concentration of lubricity additives is generally quite low.

Click to expand...

Again, that is due to US oil company lobbyists who want to avoid additional more stringent standards that are used in other developed nations.

MikeM. said:

Again, that is due to US oil company lobbyists who want to avoid additional more stringent standards that are used in other developed nations.

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Yep. And their huge primary consumer, large diesel trucks, do okay with the current standard. So they do not want to add costs to address what is less than 1% of their market.

Unfortunately even though companies can bring over tried and tested diesels which they have been selling for years in other countries, there is no guarantee that those engines will have long-term reliability in the USA.

If I owned a VW TDI vehicle, I would find a good diesel lubricant additive and keep a case of it in my trunk. Because you need to add it upon every fill up. And not all of those additives work. I saw a rigorous test of close to 20 additives and only 7 were truly effective. Amazingly, 4 of them made the lubricity worse!

Another problem is that even our gas stations and gas tankers contribute to the problem. Tankers can be used alternatively for gas or diesel. If there are still some gallons of gas in a tanker when it is filled with diesel, that contaminates the diesel and lowers the lubricity. Likewise when tanks are filled at gas stations, sometimes they start pumping gas down into the diesel tanks. They make mistakes.

Some owners of diesels will fill up with gas because it is usually 60 to 70 cents cheaper, or they can't find a diesel station. This is to be avoided at all times. Those engines and associated parts are not designed to use gas. And the gas in your tank can continue to contaminate several tankfuls as you work it out of your system. VW has stated that several diesel failures have been due to owners putting gasoline into their vehicles.

Bombadil said:

Unfortunately even though companies can bring over tried and tested diesels which they have been selling for years in other countries, there is no guarantee that those engines will have long-term reliability in the USA.

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True, Mercedes and Volvo make heavy diesel trucks for different markets. If our domestic manufacturers did not lobby for fuel standards that keep us in the dark ages we too could use the same efficient and clean burning modern diesels that are available in other developed nations.

As it is, manufacturers have to design engines for different fuel standards. But that's what the domestic manufacturers want.

Also as stringent Euro 6 regs actually become effective in more developed countries, the high sales rate for light diesel passenger vehicles is questionable in the future. Countries with subsidized diesel fuel (and lower pricing) will have different sales rates of course, as they do now.

I am attracted to the great mileage and increased torque of a diesel vehicle. And would love to have the option of a nice diesel in various Mazda vehicles. But do harbor serious concerns about them and would not be an early adopter.

Sometimes around here, diesel can cost 80 cents more per gallon than gas. Let's say gas is $3.20/gal and diesel is $4.00/gal. Then by simple math, the cost per mile for fuel would be the same between a 32 mpg gas vehicle vs a 40 mpg diesel. If I am adding additives to the diesel to be safe, that's another $2-$3 per tankful. And, thus far, diesels have tended to have higher long term repair costs.

I feel it isn't unfair to consider the long-term operating cost to be roughly equivalent between a 32 mpg gas vehicle and a 44-45 mpg diesel. Thus a Mazda 3 with 2.0L Skyactiv is likely to be significantly less expensive over the long term than a VW Golf with 2.0L TDI, as their respective EPA estimates are not all that different. It will be interesting to see what mileage numbers Mazda will get with their 2.2L diesel.

Bombadil - ^ I think some of our mazdas247.com people in Europe did the math on 2.2 diesel vs 2.0 gasser mileage difference, it came in around 25% (not the usual 30% expected with lower performance diesels), certainly still very good considering the tremendous torque. But as you mentioned for US buyers the fuel price differences plus maintenance significantly impacts total operating costs (not to mention purchase price premium of $2K+ or probably $3K+).

Maybe what I heard is all crap, but a show I watched recently said that the reason diesel is different here in NA has to do with the process we use to refine into gasoline. Our refineries are optimized to produce gasoline and a small amount of diesel. In Europe, its the other way around, they produce mostly diesel and a smaller amount of gasoline. The reason for the different in quality is largely due to the refining process. Still, it's sad that our fuel is not of the highest quality. But what can you do...In Canada anyway, there hasn't been a new refinery built (at least according to the CBC) in 30 years.

I read yesterday (will try to find the link) that Mazda is getting into electrics. First models will be out late 2015. Diesel, Gasoline, Electric Hybrid -- now that would be a trick!