Innovative Stainless Steel Applications in transport ... - Euro Inox

Table 38. Airborne emissions from the diesel engine of a bus in short-distance (city) traffic
(Mäkelä 2008). Cons. = fuel consumption.
Emission class
CO NOx PM CH4 NMHC N2O SO2 CO2 Cons.
(g/km) (g/km) (g/km) (g/km) (g/km) (g/km) (g/km) (g/km) (g/km)
EURO 3 0.6 9.7 0.21 0.03 0.10 0.035 0.0042 1340 423
EURO 4 0.5 6.8 0.04 0.03 0.06 0.035 0.0042 1340 423
EURO 5 0.5 3.9 0.04 0.03 0.06 0.035 0.0042 1340 423
The industry associations of steel and stainless steel producers have collected materialsproduction
LCI data. These inventories are available for use in Life Cycle Assessment
(LCA) studies. They all give a “cradle-to-gate” point of view, including efficient
recycling. The recycling ratio of ferrous metals for European end-of-life vehicles is
between 98 % and 99 %, while 1-2 % goes to waste as metal landfill (Beck 2004, Ridge
1998). Bus frames are fairly easy to dismantle and recycle.
6.3. Life cycle cost evaluation of bus-frame materials
The life cycle cost of a bus frame includes the materials and manufacturing costs of the
frame and the operating costs. Bus-frame structures are manufactured using welded
hollow sections and sheets. The difference between carbon steel and stainless steel
frames is that a carbon steel frame must be completely painted, to protect the welded
hollow sections from corrosion. Long frames need a large dip-painting tank, which
implies a corresponding capital investment. The chromium content of stainless steels,
however, ensures adequate corrosion protection and removes the need to paint frames.
This gives stainless steel an advantage in terms of manufacturing costs.
The operating costs of a bus frame are largely determined by fuel consumption and,
therefore, frame weight. Lower operating costs can therefore reduce the life cycle cost
of a lighter bus. Figure 71 shows how significant fuel costs are, compared to materials
costs. This is why the curb weight of a bus is important in the quest for low life cycle
cost with reduced operating costs.
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