
San Francisco Gets Three Hymotion Plug-In Prius Hybrids















In regards to refineries, how much diesel can you get from a barrel of oil versus how much gasoline? Can the refinery be operated so that a majority of the production is diesel fuel or are you always stuck with a lot of gasoline. If its the latter doesn't that mean you will always need a mix of gasoline and diesel fueled cars?


You also have to consider how much H2 (from CH4) and energy (thermal) it takes to refine gasoline from heavier crudes and make >15->5ppm ULSD.


It would be very interesting to see fuel consumption by engine displacement and power, I suspect that fuel consumption improved despite bigger engines and more power , still given the potential growth from new member states this is a worrying trend line


We can only hope that biodiesel will become a mainstream fuel in America!


good. Biodiesel is next fuel for diesel vehicle. But how we overcome Injection mechanism failure?


"Biodiesel is next fuel for diesel vehicle. But how we overcome Injection mechanism failure?"

what injector failure? unless the temperature is too cold and the fuel gels, there should be no injector failure.



I am afraid you will be disappointed. I can't find any proof, but I'm guessing that average real world fuel consumption did not change in the last 20 years.

Engines get more efficient, but cars get heavier and bigger, with more accessories, most notably air conditioning. Net result: 0.



There was an interesting discussion of this before:

I'm sure there's plenty of more info out there, too.

Rafael Seidl

@Tony -

the ratio of products depends on the source of the crude oil, but averaged across sources, a barrel of oil will readily deliver at least twice as much diesel as low-octane raw gasoline. By-products are small amounts of propane-butane (LPG) and rather larger amounts of kerosene and heavy oil - some of which will be bunker oil or even bitumen.

In Europe, only the heavy oil is hydrocracked to produce the high-octane compounds required to bring the raw gasoline up to the standard of regular or premium unleaded. Hydrocracking also yields polycyclic paraffins and aromatics (light cycle oil), which are added to diesel fuel because there are few other uses for them.

In the US, very strict emissions regs have kept the diesel share of new passenger cars very low for decades. As a result, US refineries have to hydrocrack not just heavy oil but also middle distillate to produce as much gasoline as possible - one of the reason they operate less efficiently than their European counterparts. Even so, approx. 1 in 7 gallons of gasoline consumed in the US has to be imported as finished fuel - most of it from Europe. Demand is so high that wholesale prices of regular unleaded (RON 91) have drawn level with those of the most popular grade, Euro95. German filling stations recently discontinued sales of the inferior grade.

The US uses its diesel for trucks and space heating along the Eastern coast. The rest is exported to Europe, but the volume is much smaller than that of US gasoline imports. Additional diesel sources for e.g. Italy are Ukraine and Iran, which banned diesel passenger cars from Tehran because of air quality problems. Trade sanctions have prevented refinery upgrades, so the country imports finished gasoline from India - a country whose fuel tax structure greatly favors diesel.

Now that technologies for meeting T2B5 in the US and for improving the fuel economy of spark ignition engines are becoming available, perhaps these global imbalances will be reduced. Natural gas and biofuels should also help in this regard.


Knowing that filters to remove fine diesel particles are iffy at best, & non-effective at worst, & that nano particle filter tech isn't even demonstrated, this 4+ times increase in diesels must be devastating people in European cities. Or are the studies to intimately document pollution-felled citizens...NOT being performed.

Certainly, such studies are NOT a high priority in the above posts.


I would say that a "greener" diesel might run on biodiesel or NG. There was an article on here about NG and diesel producing less emissions. Maybe a dual fueled diesel hybrid would be a good start.


@ Litesong -

I've noticed you've mentioned that DPFs aren't effective in removing ultrafine PM and nanoparticles in several other posts about diesel emissions. Do you have ANY reference for that? Any?

I have several references which show DPFs are extremely effective across that entire particle size distribution. Here are a couple: (slides 10 and 11) (slide 27)

Other references show that at the very worse, exhaust from engines with DPFs are indistinguishable from the intake air in terms of PM numbers (, “Report on Ultrafine Particles”, page 7).

If diesel engines produce most of the ambient ultrafine and nanoparticles, why have studies shown that ambient ultrafines consist almost entirely of organic carbon (OC)? The USEPA claims that diesel exhaust PM is about 75% elemental carbon (EC) by mass. EC makes up an EXTREMELY small mass fraction of ambient UF PM, about 1% according to the Southern Oxidant Study.

Other source apportionment studies have shown that GASOLINE emissions makes up a larger portion of ambient PM than diesel (see, North Front Range Air Quality Study; : Min-Suk Bae, James J. Schauer, Jeffery T. DeMinter, Jay R. Turner; “Hourly and Daily Patterns of Particle-Phase Organic and Elemental Carbon Concentrations in the Urban Atmosphere.” Journal of the Air & Waste Management Association, Volume 54, July 2004, Pages 823-833; Alan W. Gertler, “Diesel vs. gasoline emissions: Does PM from diesel or gasoline vehicles dominate in the US?” Atmospheric Environment, Volume 39, Issue 13, April 2005, Pages 2349-2355)

I've worked in the air pollution field for almost 25 years, and I don't recall ever seeing EC making up more than about 10% of speciated ambient PM. That's why I'm not convinced that even the old high-emitting diesels were a "major source" of ambient PM, much less these clean diesels with DPFs.

Litesong ,
Your right , here in northern Italy , all the kids seem to be
continually sick this winter , the local GP says he has never known
so many chest infections amongst the young !


Hi Italy...Children near freeways have extra lung disease & deaths the closer they live to freeways. New studies now indicate diesel particles contribute to society's extraordinary heart disease & death rates, whether they be in the U.S. or in Europe, where engine manufactureres are so proud of their 'highly controlled' diesel fumes.

Yes Carl, that is where my data comes from...the playgrounds & living spaces(more like death places) kids inhabit near freeways. Your pristine data from some diesel laboratory is NOT translating well to the congested highways where engine particle pollution is invading the habitats of our children, where sneaky fine & nano particles take up residence inside our children causing lung & heart disease & death. & as I have alluded to already, studies on other organs damaged by particles aren't even done yet.

Carl, take your 25 years air pollution research, find a 4 year old running diesel with a filter that hasn't been maintained properly & breath that exhaust for 3 years.

Cheap after market diesel filters have very little effectiveness. Much more expensive diesel filters must be custom tailored to the vehicle it is placed on & rigorously maintained for proper functioning. Even with proper maintainance, they are prone to long-term failure. The data on childhood lung & heart diseases & deaths near freeways prove that diesels AND autos in general are a greater danger to our children than the human child-predators we fear so much.


Litesong - are there no gasoline vehicles on those freeways? How do you know for sure it's DPM that's causing the health issues?

If DPFs fail after "4 years", why are OEM DPFs not only still effective at 150,000 miles, they actually become MORE effective than the were when new?

Do you have any comment on this?:

"...Peugeot with SiC-Diesel particle filter (DPF) has much lower emissions of nanoparticles, than generally supposed until now. The usual SMPS measurements from the CVS dilution tunnel estimate the background concentrations in the CVS dilution air, which are about 40 times higher, than the concentrations of finest particles in the exhaust gas of the vehicle....

...Due to the air filter of the CVS air inlet there are about 2 times lower particle count concentrations in the CVS air than in the ambient air...

...the particle count-concentration in the exhaust gas is about 18 times lower, than in the CVS dilution air. Due to that both gases change the roles: the CVS air is the emission source and the exhaust gas acts as the dilution air...."

"Nanoparticle Emissions from Particle Filter-Equipped Diesel Car."

The exhaust of the DPF-equipped diesel engine has fewer particles than the FILTERED air of the dilution tunnel!

What's your thoughts on the source apportionment studies (which predate DPFs by the way) which show that GASOLINE engines are a much larger source of ambient PM2.5?

I grew up on the downwind side of a major truck route (about 100 feet from the freeway), and my lungs are fine. So are my brother's. So are all of the other neighbor kids that I knew.

If you have a problem with diesels and autos in general, you must have a REAL problem with adults that smoke around children!


Hi Carl...You & your brother are 2 data points. I'm glad you 2 data points survived. A lot of kid data points didn't survive & aren't surviving. Do you NOT believe studies that kids have greater lung & heart disease & death the closer they live to freeways? Do you really believe the semi that just belched diesel fumes onto the playground is innocuous? Do you think the only problem workers face inside the cargo holds of a ships next to running diesel forklifts are the carbon monoxide emissions?

Ten plus percent of highway traffic are diesel semis. Now that so many 'civilian' diesels are on the road in Europe, diesels are blooming on the highways. Commercial diesel trucks use many times more fuel than gasoline cars. Just one diesel with malfunctioning filter will output 100 times more fine particles than cars. Some of the manufacturers jump up & down when they declare that 'our filter reduces particles by 85%. That only leaves a semi outputing 15 TIMES more particles than a gasoline car. To call diesels safe while watching diesels belch particles continually from any freeway onto a playground, is to be blind while you shake your clean paper 'data' in my face.

Smoking has nothing to contribute to this discussion. But since my parents, my brother & my uncle died of smoking & my sister is dying of emphysema, yes, I don't like smoking either.


This boils down to litesong arguing from anecdote, Carl from peer-reviewed sources. I'll take Carl's researched findings over "a gut feeling" any day...

Brian P

It's also worth noting that the diesel engines that were "on the road" in the past and even now, are no comparison to the DPF-equipped diesels that will gradually be replacing the older non-DPF-equipped diesels.

I haven't seen an acknowledgment yet that a significant portion of the traffic on these roads that are supposedly killing our kids (yet somehow I survived!) are gasoline powered vehicles ... that also emit fine PM.


Marshall...The only reason you call my words 'anecdote', is that you don't care to look up diesel articles on lung & heart problems for children & people who are in long time close proximity to freeways. They are easily found by simple googling for U.S. & European articles & fine 'googlers' can do a more comprehensive job than me.

Your attitude is the attitude people developed as congested diesels became a supporting backbone to our society. People saw diesel problems as a conflict between the methods used for short term(flowing into long term) support of their families, & those same methods having long term detrimental effects to the same members of the family.

Fortunately, short term effects on our most sensitive citizens were less 'seeable' because the sensitive were fewer in number. Unfortunately, our 'little' blindness to the 'few' diesel sensitve people, became a big 'blindness' to long term effects of diesel that downed & killed so many of our people as the decades piled up.

We 'kind of' cleaned up auto & diesel emissions from the 70's to the 90's. We put extensive medical air pollution research & study on the back burner, & gave ourselves a pat on the back. But increased congested traffic & belated studies of CT has shown the shortfall of our 'kind of' solutions to pollution.

Carl's clean 'paper' world has not transferred to the real world of freeway playgrounds. Real life (& death) has intruded into the laboratory world & smeared the results with disease & death.



Yes, but they’re exposed to PM from a myriad of sources. PM from diesel is being addressed (DPF). What about the other sources?

I believe emissions from ANY combustion source are harmful, including emissions from gasoline engines and coal-fired electric power plants.


No, which is why I support using DPFs on diesel engines. What about particulate filters on SI engines? What about children that live just downwind of a coal-fired electric power plant?

This is really digressing from the original point of my discussion, which is your assertion about DPF - “[k]nowing that filters to remove fine diesel particles are iffy at best, & non-effective at worst, & that nano particle filter tech isn't even demonstrated...” (your words from your previous post)

Sorry, I “know” no such thing. This is what I dispute. I’m sorry you feel that I’m “shaking data” in your face, but that’s the only way I know to support my point.

In the U.S. (where I live and work), ALL new diesel vehicles sold since January 2007 have been OEM-equipped with DPF - trucks, buses, and light-duty diesel vehicles. Heavy-duty over-the-road diesel trucks have to be certified for 435,000 miles. EPA wouldn’t certify these engines if the engine manufacturers couldn’t demonstrate they (DPFs) wouldn’t be effective for at least that time frame.

Here are a few more sources that support the point that DPF is VERY effective (hope you don’t feel I’m shaking data in your face):

“…Health effects were eliminated or reduced to non-significant levels [with use of DPF]…” ( slide #11)

“...The lowest number of particles are emitted from the diesel + filter vehicle, and are about one tenth of those emitted from the vehicles with the NA SI-engines….
...If fitting particle filters to diesel vehicles becomes widespread practice, petrol vehicles could become the major source of ultrafine particles...." (Färnlund et al., "Emissions of Ultrafine Particles from Different Types of Light Duty Vehicles." Swedish National Road Administration (European study)

“…DPF effective over entire PM size range…” (Matti Maricq, "Measuring motor vehicle PM emissions: Current issues and future.")

My point isn’t that diesel PM is innocuous; it’s that DPM has been essentially eliminated with DPF, contrary (apparently) to what you believe.


Carl's data is far superior to litesong's.

litesong cites a study that fails to control for other pm sources (hint: not just from diesel vehicles)

and still generalizes, ignoring the fact that the T2B5 standard in the U.S. is several times more stringent than European standards

historically, the U.S. has had emissions standards far more stringent than Europe


Children & other people existing near freeways have greater diseases & death, the closer they live to freeways. At this late date, eyesight shows that many semis are belching particles onto our playground kids near freeways.

Diesel tractor trailers are carrying too much weight trying to be accelerated by straining diesel engines with too many emissions NOT to be unhealthy to surrounding people continually near freeways. The smart people here just aren't looking up enough data.

I'm not letting gasoline engines off the hook either, but as someone said, this article is about diesels.


...according to German Federal Motor Transport Authority CO2 output of Diesel car fleet is increasing, whereas CO2 output of the patrol car fleet is decreasing.
Thus, I can hardly see any benefit in powering cars with Diesel engine instead of patrol engine. The Diesel oil should rather be used to warm our homes in winter!

And the main point is, engine efficentcy of a patrol engine is slightly less than that of a Diesel engine. BUT!
There are hardly achived by a average drive. Only Toyotas Hybrid drive comes close to the best engine operating point. All Diesels and patrol engines just operate far from the max. efficency point they can theoretical achieve.
Thus, the whole disscussion about that engine to choose is rahter nonsense. The whole drivetrain efficency and system efficency should be taken into account - and the impact of our health of course (mostly ignored by European governments).


Michel – by your own admission in some of your other posts, CO2 is increasing in the diesel fleet in Europe and decreasing in the gasoline fleet because diesel engines are disproportionately used in the larger cars there (not to mention the increasing market share they’re getting). Bosch expects efficiency to improve by at least 10% in future diesel engines and that the gap between the best advanced gasoline engines and diesels will remain about 30% (
And does that CO2 output include the higher energy requirements to refine gasoline?


I agree, and what are really being ignored are the massive HC emissions for which GASOLINE vehicles are responsible. A study in Europe (Heidi Hellén, Hannele Hakola and Tuomas Laurila, “Determination of source contributions of NMHCs in Helsinki (60°N, 25°E) using chemical mass balance and the Unmix multivariate receptor models.” Atmospheric Environment, Volume 37, Issue 11, April 2003, Pages 1413-1424) showed that 54% of the ambient NMHC is from gas vehicles (both direct and indirect emissions). Contributions from diesels were trivial (0.2%). If you remove the long-range transport (34% - most of which is probably gasoline-derived anyway), local contributions to ambient NMHC would be 0.54/0.66 = 81%. Interestingly, that’s similar to what’s been found in the U.S. ( , slide #16).

Anthropogenic VOCs (NMHC) are an air quality problem on multiple fronts. First, they’re the primary precursor to ground-level ozone (smog). Second, many VOCs are toxic in and of themselves (e.g., benzene). Thirdly, VOCs photo-oxidize to formaldehyde (a suspected carcinogen). Finally, these substances further oxidize to increasingly lower vapor pressure products which partition into the solid phase (particles). Most of these particles are in the nucleation (nanoparticles) and/or accumulation (ultrafine) modes.

It is clear to me that DPFs essentially remove diesel engines from the air quality “radar”. I’m still waiting for tangible evidence that DPFs are ineffective or are subject to high failure rates.


Carl, good point.
But I think, without promoting the Diesel, patrol cars fuel consumption would have gone down anyway. The problem is, heavy car market did hardly exist in Europe some years ago. The Diesel engine enebled the car companies to push there SUVs into the market. The consumer would hardly have excepted a SUV with 15-18l/100km fuel consumption (patrol).
But they accept 10-12l Diesel in an VW SUV. In fact, their patrol powered VW/BMW Limo or what so ever the drove before buying a SUV needed 10-12l in town as well. Thus, for most of the consumers everything is as it was.

Furthermore, I guess to produce a 2t Diesel-SUV does more damage to the enviroment than producing a 1,5t Limo.
I thing it is even more difficult to get these people out of their 2t Diesel SUV and get them into a ecofriendly 800kg vehicle.

But everying is politics, isn,t it? A 2t SUV produced in Bratislava and sold in for example Germany generates more profit than selling a 800kg compact car. On the other hand, I do not understand, why some European economies without any oil in the backyard pump their purchasing power into the hands of tribal lords in the Greater Middle East. Because they by weapons and cars made in Europe; thus send this money back and create jobs?

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