Hybrid

Why doesn't anybody make a hybrid with a diesel engine? Wouldn't that
get even better mileage?

 

One of the features of the gas-electric hybrid is that it runs very clean.
California testing indicates that some of the measured emissions are
nearing the error range of the monitoring equipment.
You can't do that with the diesel fuel currently available in the US.
Some portion of the manufacturers' enthusiasm for hybrids may be the clean
burning.

 

The electric motor has good torque at low rpms. The diesel also has good
torque at low rpm. The two characteristic tend to negate each other since both
engine types do not required additional torque at lower rpm.

However, the Smart only has a .8L diesel engine and can use all the help it
can get. I wonder if a hybrid engine in that car will get it to go faster..hmm

Pars

 

I have been told, and would like confirmation, that there is a turf war
between environmental researchers in the US and Europe.

Other things being equal, gas engines emit more of some pollutants and less
of others than a diesel engine. It is somewhat subjective to assert which
is worse. Diesels are still worse for smog; gas is still worse for the
whole earth, or something.

OTOH, if you can see diesel pollutants (like soot) people of a certain type
(like dirty hippy activists at the Sierra club)will get more frightened and
confused than if the pollutants were colorless and odorless.

On top of everything else, oil companies can get a bit more 'value added' $
from refining gas than diesel. Americans have a bad taste in their mouth
from GM's trajicomic attempts at diesel cars 25 yrs ago. Diesel is stinky.

regards,
Keith Loyd

 

The latest studies are that the diesel particulates, which were allowed for
years in the US because they don't contribute to photo-chemical smog, are
found to be in the same class as other fine particles that can lodge deep
in the lungs and cause long term respiratory problems.

The current refinery structure is geared toward producing a certain
percentage of different products from a barrel of crude. That is adjusted
to the historic needs of the consumers. When diesel cars peaked in
poularity, it upset that balance by a few percent, which was at the limits
of the adjustability in the current process. A larger adjustment would be
expensive, but the oil companies never lose money... they just charge more.
Diesel is selling for a higher price than regular unleaded now.

GM's attempts at running gas-designed cars on diesel caused grief for
them, but did not lead to the European manufacturers dropping their diesel
products. Most diesels are stinky. The VW TDI doesn't seem to be.

Diesel in medium duty working trucks is popular in the US.
Some use it because it is higher mileage. Some because of the low speed
work they do, some because they cheat and use "off-road" diesel, and don't
pay road taxes on the fuel.

 

If MPG was the only factor, I think diesel would be better, since its energy
density is higher than gasoline's. I know that at my university when they
were working on hybrid projects with MPG being the primary goal, they used a
diesel engine. However, like other posts mentioned, there's other factors
such as popularity of diesel and emissions.

 

If MPG was the only factor, I think diesel would be better, since its energy

That is not the only factor towards higher mpg:

1. Gasoline is octane derived (C8H18) whereas Diesel is cetane
derived (C10H22). There is more energy in cetane for not
much more volume than octane (denser - you are correct !).

2. Diesel engines are much higher compression than gasoline engines,
typically 17 to 22 to one versus 7 to 10 to one. Energy efficiency
is a function of the power of the compression ratio.

Typically, gasoline engines are 25% efficient, diesel engines are 35%
efficient (there are many exceptions to this rule of thumb !).

Lynn

 

Don't know if there is a "turf war", but yes, traditionally the
environmental advocates in the US have stressed pollutants (NOx,
SOx, CO, particulates, non-methane hydrocarbons) whereas Europe
has stressed greenhouse gases (CO2). Diesel, being more
efficient, releases considerably less CO2 per mile driven. But it
has higher NOx and particulate emissions. Some of these can be
addressed with more expensive aftertreatment (something akin to
cat converters used in gasoline engines), but some of that
requires cleaner diesel. Even with that, they might not meet the
upcoming emission req'ts.

California regulators had been very anti-diesel since they were
more concerned with local emissions such as causing LA basin smog.
But lately they seem to be opening the door to considering
diesels. The auto companies are also, to varying degree,
considering diesels. Probably in part due to their huge
popularity (~40% market share?) in Europe.

Honda was late to the diesel game. In fact, they bought GM/Isuzu
diesels as a stop gap. They now have their first home-grown
(AFAIK) diesel in the euro Accord.

 

Ironic that the Europeans were so late in adopting catalytic converters and
HC, CO, NOx emissions standards and now they are all gung-ho on CO2 which
is not a real pollutant at all. In fact the Euros are relatively new at
the auto-pollution "problem" but geez are they umm, enthusiastic. They are
currently cooking up some new reg on tires which eliminatees some compound
which contributes greatly to grip but is a suspected carcinogen. Frankly
the CE is a bureaucracy gone mad with self-importance.

I did 2500kms in a rented Seat Toledo diesel through France last October
and was glad I had it: gasoline was ~.95€/L and diesel was ~.78€/L. Mind
you most of the difference is tax and that's is err, adjustable... which
I'm sure is going to happen.

Note also that because of Cali regs we now have to buy low emissions
lawnmowers and flatheads don't cut it - last I looked, a Toro lawnmower had
a Honda OHV engine For me, using 6gals/year in my lawnmower and
snowblower, it all seems rather ludicrous.

I guess this is the DI diesel they announced back in 2K:
http://www.sae.org/automag/techbriefs_03-00/06.htm ?

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

 

There is no "octane" in gasoline nor cetane in diesel - they are just
convenient arbitrary mixtures, along with n-heptane in the case of octane
number measurement for evaluating antiknock/knock characteristics. There
is, in fact, no single compound which is called iso-octane - it's a
misnomer for what is, in this case, 2-2-4 tri-methyl pentane.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

 

That is not the only factor towards higher mpg:

Urggh ! Forgot the third factor about diesels.

3. Diesel engines use variable fuel to air ratios. Gasoline engines use
a constant air to fuel ratio, no matter what the speed and load.
Diesels use an unthrottled intake and the air to fuel ratio at idle
can go as low as 100 to 1, thus giving a much greater partial load
fuel efficiency than gasoline engines.

Thanks,
Lynn

 

There is no "octane" in gasoline nor cetane in diesel - they are just

True ! However, I was trying to show the greater energy in the
diesel fuel over the gasoline fuel. I have been seeing some real
funky stuff in gasoline as of late, one analysis I saw had over 300
components in it !

Thanks,
Lynn

 

First of all Honda is a conscience company when it comes to environmental
issues, or at least they are better than most. Many people buy Hybrids to
be gentle with the environment and a diesel engine is not environmentally
friendly. They emit too much smog. I would like to buy the Jetta TDI.
Great mileage, but not great in the smog department, which is a concern due
to the amount of traffic out there and being that the US is a V8, well
sometimes I think it is a V10 type of country. No one cares about any of it
around here.

Mercedes is coming out with a diesel hybrid in a couple of years.

Curt

 

Then how do you explain Honda's new diesel Accord in Europe?

 

I can't, but here is a link to an article and in the last paragraph it
states how environmentally friendly they are.

http://www.hondanews.com/CatID2003?mid=2004010527129&mime=asc

Curt

 

Small diesel cars are common in Europe because of the higher fuel costs.
Diesel is naturally more efficient then gas. Combining diesel and hybrid
in a small car is really unnecessary because of the high cost added to
the car will negate the saving from fuel efficiency.

Past diesel cars sold in the states have given a bad name to diesel to the
common automotive buyer. Even though it has proven to be more fuel efficient
and diesel engines are much cleaner then they were 20 years ago, it just
hasn't caught on to the average American car buyer.

Diesels sold in the US are mainly larger engines for 3/4 and 1 ton pickups.
But if you were in the market for such a large truck, you will notice that
the diesel engine isn't the base engine but usually a $5,000 option.

A Civic LX sedan starts at 15,360 while a similarly optioned Civic Hybrid
is $19,650 or $4,290 more.

Add the 2 together and you are looking at spending $9k more for a diesel
hybrid over a similarly optioned vehicle. That $9k isn't enough to
justify the fuel saving for small cars.

But things are changing. Hopefully we will find diesel hybrids in our
larger vehicles like delivery trucks or 18 wheelers what travel hundreds
of thousands of miles a year criscrossing the US deliving goods. $9k
more is nothing compared to the fuel savings they will get. Even our
military has requested diesel hybrids for their vehicles. They want
vehicles that can generate electricity to power devices in the field
and they also want vehicles that can go silent (via electric motors)
for covert operations without having to charge then up (electric only).
I only see good things to come from diesel hybrids in larger vehicles.
Work crews could use their pickups to power their power equipment instead
of having to buy a separate power generators.

Already all locomotives built today are diesel hybrids. And all of the
newest massive cruise ships are diesel hybrids.

 

Interesting point. Volkswagen is selling a Lupo turbo diesel in Europe
that gets 78 MPG. (No typo, seventy eight. And those are US miles and US
gallons, not those supersized imperial gallons).

 

A lot of interesting points have been raised. Yes, gasoline ICE's
benefit more from hybridization than diesel. That is primarily
because spark-ignition gasoline engines have large pumping losses
when operating in normal light throttle driving. But that doesn't
mean that diesel would not get a significant benefit from
hybridization. It would.

But a lot which perhaps has not been given its due is the vagaries
of the market. Due to high gas prices, Europe prizes high fuel
economy. Yet hybrids aren't popular there. Conversely, US drivers
are known for prefering low rpm torque to buzzy high-revving hp.
Yet US drivers shun high torque diesels. Some of it just isn't
logical and rational reasons for it just don't necessarily apply.

Oh, as to the "3 liter" (that's 3L/100km) Lupo, it has been
called a failure in the European marketplace. That has been
ascribed to it being too expensive for what it delivers.

 

With so many diesel options in Europe, a gasoline based hybrid that
merely matches the fuel economy of a diesel may not attract a lot of
attention. And non-hybrid gasoline engines that are smaller than
those in the US, with better fuel economy, are also available there.

Perhaps a diesel hybrid may attract some more attention, both in
Europe and the US.

 

Is there actually any scientific evidence that hybrids really are more
environmentally "gentle" in the overall balance? Has the total
energy/pollution bill been fully accounted for ? I have my doubts and the
FFV fraud being committed in the Mid-West U.S. only increases my
scepticism.

They may or may not sell it in the U.S. though. As has alreay been
mentioned in this thread, the diesel fuel in Europe burns much cleaner and
is therefore amenable to exhaust clean-up. There is also a much lower use
of heavy petroleum distillates for home heating in Europe so they have a
stronger incentive to make use of diesel as a motor fuel.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??