Environmental Engineering Reference
In-Depth Information
Transportation accounts for 50% of US urban air pollution and 33% of US
GHG emissions.
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Today 50% of all Americans live in areas that don't meet air quality
standards.
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Global oil consumption is expected to reach 119M bbl a day in 2025, 60% of
which will be supplied by the Organization of the Petroleum Exporting
Countries (OPEC).
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The Energy Information Administration (EIA) estimates that imports will
constitute 61% of US liquid fuel demand in 2030.
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Electric drive vehicles can reduce petroleum consumption by 40% and emis-
sions by 50%. Hybrid electric transit buses see reductions in particulate matter
by nearly 90% and nitrous oxides by up to 50%.
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Vehicle electrification is now a key aspect of virtually all automotive and
heavy transportation manufacturers' product development and marketing plans.
Table 1.5 highlights this electrification path for the automotive case [8].
Many studies put the sort of engine actions and vehicle electrification activities
listed in Table 1.5 into the perspective of installation cost, on-cost, versus their CO
2
reduction performance. Figure 1.11 illustrates this for the case of engine actions
designed to improve efficiency through higher thermodynamic efficiency and
emission reductions through more complete combustion process and after treatment
as needed. Figure 1.12 extends this same format to the case of vehicle electrifica-
tion and notes, in particular, the existing case of hybridization as one path to
electrification and a second, much higher opportunity, for the case of MEVs,
including plug-in electric vehicle (PHEV), range extended electric vehicle (REV)
and battery electric vehicle (BEV).
In Figure 1.11 the engine optimization technologies include electric spin-up
turbo charger, cylinder deactivation or variable compression ratio, GDI and elec-
tromechanical valve actuation (EVA), now being approximated by variable valve
timing and lift (VVTL).
1.2 Limits of engine-only actions
As Figure 1.11 shows, the low-hanging technology fruits are already being har-
vested in the $50/%CO
2
to $100/%CO
2
range. Beyond this, more advanced tech-
nologies such as HCCI that blurs the distinction between Otto cycle and diesel
cycle operation are being pursued. As Figure 1.12 demonstrates, the capability to
push deeper into CO
2
reduction requires higher levels of vehicle electrification and
the introduction of MEVs: PHEV, REV and BEV.
Coinciding with engine actions to lower CO
2
emissions are the quest for
cleaner fuels, including
Ethanol, bio-diesel, cellulosic diesel and ethanol, jatropha-derived diesel and
other crop-to-wheels fuels.
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Electricity and hydrogen top the list of energy carriers.
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