November 2004
http://www.dieselnet.com/
Nissan launching Quon truck with urea-SCR system
Japanese truck and bus manufacturers have been developing emission
systems to meet the next set of Japan's emission standards ("new long
term") that become effective from October 2005: NOx = 2 g/kWh and PM
= 0.027 g/kWh. At the time of their introduction, these will be the
most stringent HD diesel emission standards in the world (they will
remain so until the introduction of the 2007 limits in the USA). One
of the possible approaches considered by some manufacturers for NOx
control is urea-SCR.
Last week, Nissan Diesel has released its 2005-compliant Quon truck,
which is the first commercial vehicle in Japan fitted with a urea-SCR
catalyst. PM is reduced through in-cylinder methods, such as high
pressure fuel injection. NOx is reduced over the catalyst, through
reaction with urea (in the SCR technology, water solution of urea
must be carried on the vehicle and injected upstream of the catalyst).
It is not clear what type of SCR catalyst has been used by Nissan.
Earlier evaluation work of SCR systems performed by Japan Automobile
Research Institute (JARI) indicated that vanadium emissions--a
possible health concern--are possible in trucks using vanadium-based
SCR catalysts.
The 25-ton GVW Quon truck is powered by the GE13 6-cylinder, 13-liter
diesel engine, which is available in 257-302 kW power ratings.
Following the SCR technology path is also Mitsubishi Fuso Truck & Bus
Corporation. Urea-SCR was featured in the Mitsubishi 6M70T
turbocharged diesel engine, which was unveiled at the Tokyo Motor
Show earlier this November.
Manufacturers who support urea-SCR have been working to create the
distribution infrastructure for urea solutions. Following
negotiations with Nissan Diesel, 800 gas stations throughout Japan
agreed to supply urea.
According to press reports, the two other major commercial vehicle
manufacturers, Hino Motors and Isuzu Motors, favor the EGR and diesel
particulate filter technology rather than SCR for meeting the 2005
emission standards.
Press release (in Japanese):
http://www.nissandiesel.co.jp/newsrelease/2004/1118quon.html
Asahi Shimbun article (in English):
http://www.asahi.com/english/business/TKY200411270147.html
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