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It is true that
burning equal volumes of gasoline or diesel- Diesel will
produce more CO2 as it has a higher ratio of Carbon to
Hybdrogen than gas. However, when consumed in a Diesel the
higher energy density of the fuel coupled with the thermal
efficiencies of the Diesel engine will result in a net
reduction of CO2 for the same amount of work done (or
distance traveled) over a gasoline powered unit of same
size/weight/drag, etc. Here ia an analysis done by Bosch
which is a true "apple to apple" comparison. Bosch tested
two Honda Accords, a gasoline unit with the 2 litre iVTEC
and a 2.2 Litre Honda i-CTDi Diesel now being sold in
Europe. The gas model produces 140 ft/lbs of torque and 155
HP. The Diesel produces 250 ft/lbs torque and 140 HP. On
the EU combined drive cycle, the Gas Accord consumes 8
litres of fuel in 100km. (About 35 MPG) The Diesel only
needs 5.5 L of fuel to go the same distance. (About 51
mpg). This indicates an efficiency gain over the gas Accord
of about 46%. To state this performance in terms of CO2
emissions, the gas Accord produced 304 grams/mile of CO2.
The Diesel produced 233 grams/mile. That is nearly 25% less
CO2 emission even though, as you correctly pointed out, the
Diesel fuel is laden with more Carbon the gasoline. Other
makes were also analyzed with similar and consistent
results.
As for Biodiesel-- the energy equation for Biodiesel is
generally accepted as 3.2/1 for Soy based fuel and 4/1 for
Canola based fuel. This means that if I am operating a
biodiesel production facility, every 1000 watts I invest in
the process will yield 3200 watts of Soy Biodiesel or 4000
watts of Canola Biodiesel. This is one of the best energy
returns among the renewable fuels. It is far better than
the (controversial) 1.4/1 ratio for Ethanol or the upside
down energy ratios for Hydrogen and the synthetic
gas-to-liquid coal based technologies. In addition, a
gallon of biodiesel has only 7% less energy than a gallon
of diesel. A gallon of Ethanol has 37% less energy than a
gallon of gasoline. It is interesting to note that the
automoakers are putting bigger gas tanks in their flex fuel
vehicles so consumers can still drive the same distance per
tank! Of course, they will pay the difference at the pump.
Market studies: I am not reffering to Ricardo. Actually my
data comes from J.D. Power and Synovate Motoreasearch who
found better consumer acceptance of light duty clean
Diesels and predict that light duty diesels will outsell
Hybrids in the next 5-7 years. (Hybrids at 3% of sales,
Diesel at 10%) By the way, the pollution problem from
automobiles is, essentially, solved. Lots of things
contribute to air pollution. It is not fair to blame dirty
air on what comes out of the tailpipe of a late model
automobile, regardless of its power train. Of the approx.
5700 million metric tons of CO2 that the US economy pumps
into the atmosphere every year, only 32% derive from
transportation (Including air, sea, rail, autos & trucks).
Saab demonstrated years ago that their Trionic engine
management system actually produced cleaner "air" (less the
O2) coming out the tailpipe than the ambient air found in
downtown L.A.
As for incentives for diesel/hybrids; you are correct in
that they will be expensive. But it is possible that
upcoming Carbob Emission laws will mandate or at least
subsidize diesel/hybrids because this technology provides
the greates amount of CO2 reduction.
Without giving away the show, let me summarize where the
industry is going: Emissions regulations, including
restrictions on carbon output, are the primary drivers of
vehicle design. Extensive aftertreatment systems are needed
to get diesels clean enough to meet the essentially zero
emission levels for NOx and PM. These aftertreatment system
are expensive and require additional fuel to regenerate
them. This creates cost and fuel penalties which could
destroy the cost advantages that Diesels have always
enjoyed, especially in the world of Heavy Duty. Thus the
Diesel is in a fight for its life! Diesels have
traditionally utilized a highly stratified combustion
process. Gasoline has traditionally used a homogenous
process. We will see a merging of technologies. Gasoline
will move toward stratification and higher compression
ratios. Diesels will move toward homogeneous mixtures and
lower compression. in the meantime, synthetic fuels are
being developed which may optimize a multi-phase combustion
mode engine switching between stratified DI or HCCI as it
moves from idle to part load to full load and back. The
compression ratio may be in the neighborhood of 15/1 and
possibly use a synthetically produced fuel low in carbon,
no sulphur and other inorganics which will producing
managable levels of emissions with low CO2. That is the
master plan!
burning equal volumes of gasoline or diesel- Diesel will
produce more CO2 as it has a higher ratio of Carbon to
Hybdrogen than gas. However, when consumed in a Diesel the
higher energy density of the fuel coupled with the thermal
efficiencies of the Diesel engine will result in a net
reduction of CO2 for the same amount of work done (or
distance traveled) over a gasoline powered unit of same
size/weight/drag, etc. Here ia an analysis done by Bosch
which is a true "apple to apple" comparison. Bosch tested
two Honda Accords, a gasoline unit with the 2 litre iVTEC
and a 2.2 Litre Honda i-CTDi Diesel now being sold in
Europe. The gas model produces 140 ft/lbs of torque and 155
HP. The Diesel produces 250 ft/lbs torque and 140 HP. On
the EU combined drive cycle, the Gas Accord consumes 8
litres of fuel in 100km. (About 35 MPG) The Diesel only
needs 5.5 L of fuel to go the same distance. (About 51
mpg). This indicates an efficiency gain over the gas Accord
of about 46%. To state this performance in terms of CO2
emissions, the gas Accord produced 304 grams/mile of CO2.
The Diesel produced 233 grams/mile. That is nearly 25% less
CO2 emission even though, as you correctly pointed out, the
Diesel fuel is laden with more Carbon the gasoline. Other
makes were also analyzed with similar and consistent
results.
As for Biodiesel-- the energy equation for Biodiesel is
generally accepted as 3.2/1 for Soy based fuel and 4/1 for
Canola based fuel. This means that if I am operating a
biodiesel production facility, every 1000 watts I invest in
the process will yield 3200 watts of Soy Biodiesel or 4000
watts of Canola Biodiesel. This is one of the best energy
returns among the renewable fuels. It is far better than
the (controversial) 1.4/1 ratio for Ethanol or the upside
down energy ratios for Hydrogen and the synthetic
gas-to-liquid coal based technologies. In addition, a
gallon of biodiesel has only 7% less energy than a gallon
of diesel. A gallon of Ethanol has 37% less energy than a
gallon of gasoline. It is interesting to note that the
automoakers are putting bigger gas tanks in their flex fuel
vehicles so consumers can still drive the same distance per
tank! Of course, they will pay the difference at the pump.
Market studies: I am not reffering to Ricardo. Actually my
data comes from J.D. Power and Synovate Motoreasearch who
found better consumer acceptance of light duty clean
Diesels and predict that light duty diesels will outsell
Hybrids in the next 5-7 years. (Hybrids at 3% of sales,
Diesel at 10%) By the way, the pollution problem from
automobiles is, essentially, solved. Lots of things
contribute to air pollution. It is not fair to blame dirty
air on what comes out of the tailpipe of a late model
automobile, regardless of its power train. Of the approx.
5700 million metric tons of CO2 that the US economy pumps
into the atmosphere every year, only 32% derive from
transportation (Including air, sea, rail, autos & trucks).
Saab demonstrated years ago that their Trionic engine
management system actually produced cleaner "air" (less the
O2) coming out the tailpipe than the ambient air found in
downtown L.A.
As for incentives for diesel/hybrids; you are correct in
that they will be expensive. But it is possible that
upcoming Carbob Emission laws will mandate or at least
subsidize diesel/hybrids because this technology provides
the greates amount of CO2 reduction.
Without giving away the show, let me summarize where the
industry is going: Emissions regulations, including
restrictions on carbon output, are the primary drivers of
vehicle design. Extensive aftertreatment systems are needed
to get diesels clean enough to meet the essentially zero
emission levels for NOx and PM. These aftertreatment system
are expensive and require additional fuel to regenerate
them. This creates cost and fuel penalties which could
destroy the cost advantages that Diesels have always
enjoyed, especially in the world of Heavy Duty. Thus the
Diesel is in a fight for its life! Diesels have
traditionally utilized a highly stratified combustion
process. Gasoline has traditionally used a homogenous
process. We will see a merging of technologies. Gasoline
will move toward stratification and higher compression
ratios. Diesels will move toward homogeneous mixtures and
lower compression. in the meantime, synthetic fuels are
being developed which may optimize a multi-phase combustion
mode engine switching between stratified DI or HCCI as it
moves from idle to part load to full load and back. The
compression ratio may be in the neighborhood of 15/1 and
possibly use a synthetically produced fuel low in carbon,
no sulphur and other inorganics which will producing
managable levels of emissions with low CO2. That is the
master plan!
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