New VW Diesel Could Match Hybrid Mileage

PZEV is more of a gimmick, especially when comparing emissions of different fuels. The PZEV-certified version of the Passat 1.8T produces much higher well-to-wheel emissions than the ULEV-certified Passat TDI across-the board...




Gas vs. Diesel Well-to-Wheels Emissions


Even just taking the "urban" emissions into account (and that's the only test cycle (FTP) that has any difference in emission levels between LEV, ULEV, and SULEV), the Passat TDI is still significantly lower in WTW emissions than the PZEV Passat 1.8T, based on EPA upstream emission factors...


WTW Urban Emissions of 2014 VW Passat TDI and 2014 Passat 1.8T PZEV
(Using FTP75, “city” fuel mileage, “Distribution” WTP emissions, adjusted @150K miles)

2014 Passat TDI (30.8024 mpg (from unrounded EPA value))

(Grams/Mile)

Emission..........................WTP...............PTW...............WTW Total

NMOG/VOC....................0.005..............0.042.................0.047
CO...................................0.003..............0.2.....................0.203
NOx.................................0.015..............0.04...................0.055
PM..................................0.001..............0.009.................0.010


2014 Passat PZEV (24.4546 mpg (from unrounded EPA value))

(Grams/Mile)

Emission.........................WTP...............PTW................WTW Total

NMOG/VOC..................0.204...............0.012*..................0.216
CO.................................0.004...............0.2........................0.204
NOx...............................0.018...............0.01......................0.028
PM................................0.001...............0.011.....................0.012

*includes evaporative vehicular emissions

Combining ozone precursor emissions (NMOG+NOx)...

(Grams/Mile)

Emission.....................2014 Passat TDI.......................2014 Passat 1.8T (PZEV)

NMOG+NOx.....................0.098.................................................0.244
CO....................................0.2.....................................................0.2
PM...................................0.010.................................................0.012

By the way, what "diesel tax credits" are you referring to? Federal tax credits expired several years ago (2010) to the best of my knowledge.

 

Would you agree that a clean diesel would make a superior range extender to gasoline in a Volt-like car?
Would you make those same points above about the VW XL1?
That car (a diesel!) makes the Prius look like an out-of-tune Ford Excursion.

Look, "diesel" can mean anything from a supercar to a semi truck. "Hybrid" can mean anything from a transit bus to the Porsche 918.

We need to stop stereotyping the technology. They both have their place. It simply depends on the application.

 

"In the 1970s the Japanese Government, in response to the oil shocks and air pollution concerns, launched a series of market expansion plans for the development and commercialization of low emission vehicles (LEVs) and set targets for their uptake within Japan.
...
Over the course of two decades the MITI led a number of specific R&D initiatives, including the 5-year government-industry R&D programs launched in the 1970s, the electric vehicle field tests run through the late 1990s, specific research into new fuel cell and battery technologies as well as funding for high energy efficiency hybrid vehicles. The MITI funded programmes are usually long (>10 years) and divided into three phases starting with R&D on basic technologies, then demonstration and prototype, and finally, production and early deployment; the private sector is expected to increase its share of responsibility as the technology comes closer to commercialisation (Daito, 2002).
...
LEV growth was catalysed by Toyota’s launch of the Prius hybrid electric vehicle in 1997, which saw technology developed for BPEVs put to use in a petrol-based HEV configuration."
Government policy & the development of hybrid and electric vehicles in Japan | Think Carbon

Early on the government programs focused on BEVs. It shifted when the BEVs weren't being embraced by the public at the time. The battery and electric drive train R&D would have direct and indirect application to hybrids, though.

 

Is the bolded part fuzzy enough for you ? Apparently so.
It shouldn't. The PSD, programming, and inverter are what makes the Prius, and that was all development by the car companies without government support.

 

We still see the FUD on hybrid batteries and costs from time.

We can't condemn people for doing so while continuing to support the FUD that new diesels are as dirtier as the pre ULSD and emission controls models.

 

Diesels are heavier and more expensive for the same power output. In a volt-like car, phev 20+ even VW has chosen a gasoline ice. A phev, or even a full hybrid like the prius, isn't well served by diesel. The diesels strength is low end torque and efficiency at low loads, while a hybrid's battery/motor supplies low end torque and allows engine off operation at low loads. The higher percent of electric miles the harder it is for the diesel to make sense. The mazda skyactiv 1.6L, bmw 1.5L, or ford ecoboost 1L seem like good fits for the car. In more expensive heavier vehicles a diesel may make more sense.

XL1 definitely is best as a diesel. Its all about mpg, and diesel has more energy. If you were going to build it as more of a production car, instead of an engineering limited production, a small gasoline engine makes more sense.

+1

 

What? You claimed Toyota got no help from the Japanese government in developing the Prius when did. It may not have been help in the form of a project and subsidies directly for a hybrid vehicle, but neither was the Partnership for a New Generation of Vehicles.

PNGV's goal on inception was just to develop a 80mpg car. The how wasn't determined, and the decision to use diesel hybrids for the final concepts was made over the course of the R&D work. It also covered work on things like hydraulic hybrids, clean diesel tech, and improvements in the cost of manufacturing with light weight materials, like aluminum. Things that have only an indirect connection at best to hybrid electric car development.

It appears the move to ULSD and tighter diesel emission standards came out of PNGV's research. That might not lead to the adoption of diesel personal vehicles, but it does clean up the trucking industry.

 

The analysis of WTP emissions makes me want to ask about the energy usage required to refine diesel vs. gasoline. My understanding is almost all diesel is distilled directly from crude and therefore there is a limited supply of diesel --you can get just so much out of a barrel of crude. This, combined with high worldwide diesel demand and, in the US, a higher tax, makes it more expensive than gasoline. Gasoline on the other hand is often derived by cracking crude distillates. Cracking seems to require temperatures of about 900F. and that energy has to come from somewhere, so perhaps this is the source of the higher WTP emissions.

I also want to note that the Prius uses about 1/2 as much fuel as the VW 1.8T used in the emissions comparison above. So, if someone really wants to compare a Prius to a VW TDI, they should halve the columns shown for the 1.8T.

 

MITI gave honda and toyota direct subsidies for every hybrid they sold at the beginning. Hybrids were not specifically funded for R&D, but the BEV program did fund much of the electronics, motor, and battery R&D used in the hybrids. Ford, GM, and Daimler Chrysler had other direct government subsidies. The MITI program was much more effective than the American program. In looking back those direct subsidies for each car actually produced was instrumental in the prius sucess. It gave Toyota money to produce the successful second generation. It likely would have taken longer if MITI had not done this funding.

No! One huge criticism of PNGV was that the government was pushing automakers to build cars that could not pass EPA emissions laws. The US was a follower country, not a leader on low sulfur diesel. I am not sure where it started, but hong kong had ultra low sulfur diesel in 2000. Like lead, the sulfur in diesel is incompatible with some emissions control equipment.

 

That's basically my understanding. However, diesel (middle distillate) can also be "cracked" from heavier components (called "light-cycle oil"), but that product has a very low cetane number.

Also, the higher WTP VOC emissions are mostly the result of the much higher evaporation rate of gasoline compared to diesel fuel.

I agree, but the comment was made that PZEV was a delineation that diesel is unable to meet (technically correct, but not a distinguishing feature from an air quality perspective, as I tried to demonstrate). Actually, the BMW 328d (2.0 diesel) technically meets SULEV (see my post #22 in this thread) and theoretically could be certified PZEV if it could carry those emission levels through 150K miles. Since diesel fuel is essentially non-volatile, meeting CARB's definition of "zero" evap emissions would not be an issue.

 

Wxman pointed you can crack diesel from heavier components. It might be possible to use catalytic reforming to make it from the lighter, smaller chain molecules. Reforming is used to make gasoline of usable octane, and high value solvents. So if possible, it isn't done because of profit margins.

My conclusion was based on this:

• Oxygen-rich air supplier for clean diesel technology (1999 R&D 100 Award)
• Development of aftertreatment devices to remove nitrogen oxides from diesel exhaust with efficiencies greater than 90 percent, when used with diesel fuel containing 3 ppm of sulfur

Partnership for a New Generation of Vehicles - Wikipedia, the free encyclopedia

 

The fractions at a US refinery produce more diesel than is needed in the market. These fractions are exported as diesel, because it makes economic sense. If the mix in the US changed to more diesel, the refineries could change their production. Gasoline is more energy intense to produce because we use more of it than the fractions available in the oil. Either Gasoline or Diesel can be manufactured, its just a question of production costs.

Lets take a few steps back. First the oxygen rich air supplier is not a key diesel technology. It was created at ANL before the PNGV, and simply rolled into the program. During the timing of the program they found ways to make it less expensive, and they credited this to PNGV, but it really didn't do anything for the program.
Argonne TDC: Clean Diesel Technology.

Using these membranes would decrease particulates, but increase NOx. Particulates were lowered with UL sulfer diesel and dpf.

SCR is the main after treatment for clean diesel NOx. This was invented before the 80s, but sulfur disrupts it. Removing the sulfur from diesel is expensive, unlike simply not adding lead. EGR systems reduced the amount of NOx formed, but making engines to produce low NOx made the diesels less efficient. I don't know the history of the regulation. Removing the sulfur also removed many of the particulates, which seems like more of a problem. UL Diesel plus dpf is responsible for the bulk of diesels dropped emissions. SCR to remove NOx allows more efficient diesels on the road that have low emissions. Again the US did not lead in removing more sulfur from diesel, which allowed the advances. Mazda appears to be able to drop NOx low enough without SCR in their new diesels, but it sounds like they are not as efficient as the best in class using SCR systems.

What is SCR? | Facts About SCR

 

Are you sure about this? I agree diesel's role is limited in PHEV-20's and less, but I still believe it would be superior in an EREV.

Simple reason is it's in continuous operation....which is good since there are problems cycling diesel on and off.
And it can operate at its most efficient setting. A Volt with a diesel should have a lower cost-per-mile than the current gasoline volt (which means diesel mpg wouldn't have to be much higher, since current Volt uses premium).

I agree a clean-diesel Volt would weigh slightly more (knocking a few miles off EV range) and also cost more.
It may cost so much more that the extra price may never be compensated for by reduced cents-per-mile.
But, if there were someone out there who is willing to pay more, for whatever reason, the cost and the emissions per mile should be less than gasoline.

 

No, I am not sure what is in the labs. It all depends on cost. IIRC the peak efficiency of the prius atkinson engine is 38%, the vw tdi is 42%. Both can be improved, but lets go with that delta with today's technology. Diesel also has more energy, but today costs about as much more as its extra energy, but say its 15%, and we stay in peak, which is not really that likely, we get (1.15)x(42/38)=1.27 or about 27% more efficient. That sounds good if we can get it. But now figure 200lbs of added weight makes all those electric miles less efficient, and it starts to look a little worse, we had to pay for the batteries. Let's use the volt's numbers but assume they had put a prius like atkinson in there, 62% electric miles 42 mpg gas, or 42x1.27 = 53 mpg diesel. In a 15,000 mile year, that would be 5700 miles or 136 gallons of gasoline, 107 gallons of diesel. Say the gas cost $4 and diesel $4.20 which is lower than today's diesel premium, that's less than $100/year, and these are favorable diesel numbers. Add in extra maintenance for more oil changes, dpf filter, etc and I doubt people would pay any more for it than one with a prius like engine.

But the next volt could use an atkinson or multimode (like skyactiv) or turbo. The economic route is for a more efficient gasoline engine, not a diesel here.

emissions per mile would likely be lower than gasoline if you can get all the diesel efficiency in there, but I can't see people paying more for a diesel car here. That diesel price and weight could buy more batteries if that is the trade-off. Now if you are a long distance truck phev, a diesels numbers would likely look much different.

 

With FUD, then why are Priuses everywhere on the highways and back roads as compared to the extremely sighted Volt?

Folks must be taking a real liking to the Prius. They are selling.

DBCassidy

 

Just to highlight the fun to drive side of hybrids versus diesel, here is porsche's opinion
Porsche R&D Boss Wolfgang Hatz Talks Hybrids, Manuals, and Racing – Feature – Car and Driver | Car and Driver Blog

bold italics are mine

 

I like the concept of a diesel range extender. Can be made to run B100/WVO with minimal modification.
It paves the way for an apocalyptic future where we charge up EVs for our daily commute with rooftop solar or wind, and we don't take road trips unless we've saved up enough fryer grease (or grown enough biofuel in the backyard)

 

Then when you factor the higher cost of diesel with low sulfur - you still have a ride falling short of the Prius . . . despite the fact that fuel oil has higher btu's.
.

 

It depends what car a diesel is in to see if it falls short of the prius.
Compare Side-by-Side
BMW has the effiecency vw is shooting for in the next generation. The 328d is just a little faster than the camry hybrid. RWD and sound proofing make the base bmw heavier than the base camry, but diesel versus hybrid they are about the same. Of course the bmw is more expensive being a bmw. The vw announcement is about trying to bring the price down.

How do they do? The camry hybrid gets 8 more mpg in the city, the bmw diesel gets 7 more mpg on the highway. The transmissions are equaly different, an eCVT versus a 8 speed automatic. Both do much better than their gasoline ice models as seen above. The camry hybrid though improves mainly just in the city, the bmw in the city and highway equally. YMMV. The camry is going to win on 50/50 drives even without accounting for the energy or money, just gallons. Do a mainly highway driving though, that mix is going to matter, and how you compare diesel to gas in value. Some will want the 6+ speed torque diesel, some the ecvt hybrid especially if you can't hear the engine note. Its good to have choices, but if you are doing the sporting thing - porsche has weighed in and likes gasoline hybrids better. If you are just doing endless highway miles, diesels might be better. A mix hybrid is going to win.

 

It's really too bad it is a limited production run on the XL1. Any word on MSRP?
It's time to get serious about diesel technology.
What we need is this:
Loremo: The 'Low Resistance Mobile' - MSN Autos

Imagine 150 mpg.
Cheaper TCO than a Tesla, with refueling as fast as battery swap.
Cheaper cost-per-mile than a Volt; cheaper to buy as well
Equally priced with a LEAF, but far superior range and re-fuel times.

I come up with a price-per-mile of $4/150 mpg = 2.67 cents/mile, or about 3 cents/mile incl. electricity
How many EV's can match that?
Emissions-per-mile is also going to be very competitive with EV's. depending on where in the U.S. plugged in

Think abou this: the cost-per-mile of driving a Loremo would be greater than a Prius only when diesel becomes more than $12/gallon!


Prius: $4/50 = 8cents/mile
Loremo: $12/150 = 8cents/mile