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14 November 2007.
Last summer, Nissan announced a new
clean diesel technology using high-performance catalysts
that may be able to meet the State of California's
standard for super-ultra-low emission vehicles (SULEVs),
equivalent to the Tier2Bin2 emissions requirements.
To reduce diesel emissions, Nissan's
new technology uses three components working together:
modulated-kinetic (MK) combustion, high-performance
catalysts, and advanced engine control systems.
While the modulated-kinetic
combustion curbs toxic emissions at its origin-phase by
simultaneously reducing oxides of nitrogen (NOx) and
particulates, the new engine systems exert more precise
control of oxygen in the exhaust for better fuel
efficiency and less emissions.
Nissan says its unique
Hydrocarbon-Oxides of Nitrogen (HC-NOx) trap catalyst
technology comprises a breakthrough construction which
incorporates a HC-trap layer in the NOx-trap catalyst.
The HC-trap layer serves to trap the HC which is
oxidized to generate hydrogen (H2) and carbon monoxide
(CO), which in turn react with the NOx gases trapped by
the NOx-trap layer to produce nitrogen (N2) and carbon
dioxide (CO2) gases, in addition to water vapor (H2O) as
end products. The chemical reactions reduce HC and NOx
resulting in cleaner tail-pipe emissions.
The third Japanese carmaker had
previously announced clean diesel technology that met
the U.S. Tier2Bin5 emissions standards.
With this new HC-NOx trap catalyst
technology, Nissan believes it will be able to achieve
cleaner diesel emissions in future vehicles that will
meet the stringent SULEV-standards set by the state of
In order to meet the SULEV-standards,
hydrocarbons in vehicle emissions must be exhaust
reduced by about 90% and NOx levels must be reduced by
70% versus Tier2Bin5 standards. That is 0.0062g/km
(0.01g/mile) of HC(NMOG) against 0.0559g/km
(0.09g/mile), and 0.0124 g/km (0.02g/mile) of NOx
against 0.0435g/km (0.07g/mile) made possible by
previous Tier2Bin5 technology.
Under the Nissan Green Program 2010,
Nissan has announced plans to expand clean diesels to
surpass current emission standards. Looking ahead,
stricter regulations will be imposed in major markets
including Japan, US, and Europe within the next few
These new clean diesel engines will
comply with future exhaust emission regulations in these
markets. In Japan, a new clean diesel engine is
scheduled for introduction in the X-TRAIL SUV in autumn
2008. In the U.S., a clean diesel engine that complies
with the Tier 2 Bin 5 requirements is scheduled to be
available on the 2010 Maxima.
As of May 2006, 80% of all new
gasoline-fuelled Nissan cars sold in Japan have been
certified as Super Ultra-Low Emission Vehicles
(SU-LEVs). Nissan estimates that the resulting effect on
reducing exhaust emissions is virtually the same as if
electric vehicles and other clean cars accounted for 40%
of the company's unit sales volume in Japan. SU-LEVs
emit 75% fewer oxides of nitrogen (NOx) and non-methane
hydrocarbon (NMHC) emissions than vehicles complying
with Japan's 2005 exhaust emission regulations.