Future Trends Surrounding Diesels
 3.2 Trends at the Department of Energy
Figures for diesel fuel consumption broken down by vehicle weight class have also been predicted to double from 1992 levels by 2007, with the increase for each class varying from 180% to 240%.
Table 7: Trends in Consumption in Diesel Fuel by Vehicle Weight Class (in billions of gallons)
| Vehicle Weight Class and / or Location |
1992 |
1997 |
2002
(est.) |
2007
(est.) |
| On-road vehicles |
22 |
29 |
36 |
43 |
| Light-duty trucks |
1.4 |
2.0 |
2.7 |
3.3 |
| Medium-and heavy-duty vehicles |
21 |
27 |
33 |
38 |
| Heavy heavy-duty vehicles(HHDVs) |
20 |
25 |
30 |
35 |
|
From DOE Report NREL/SR-540-32689
Total annual sales of all diesel vehicles, including trucks, buses and passenger cars was 300,000 units in the 1990, but reached the 570,000 level by the mid-1990s. EPA data indicates that this will reach 670,000 by 2007, and is further predicted to reach the 700,000 vehicle level in 2010.
During this time, increasingly stringent emission regulations will come into effect with Tier 2 for light-duty vehicles in 2004 and for heavy-duty vehicles in 2007. The increasing demand for diesel vehicles together with increasingly stringent regulation means that technology for after-treatment equipment is needed. Any number of technologies are now under study, but it is important to develop technologies that reduce emission levels while maintaining the diesel engine's superior fuel economy.
To this end, the DOE has shown great interest in selective catalytic reduction (SCR) processes utilizing urea to achieve major reductions in NOx and PM. In the US, these units have been used on stationary diesels at factories for more than 20 years, and in Europe plans are in place for their application to diesel vehicles.
Table 8: Post- Combustion Treatment Devices for Diesel Exhaust Systems
Exhaust Gas
Control Device
(After-Treatment ) |
Expected Reduction in Nox levels |
Expected Reduction in PM levels |
Current Feasibility |
| NOx Absorber Catalyst |
80% or more |
30% |
Prospect for availability in 2007 |
| Diesel Particulate Filter(DPF) |
None |
80%-90% |
Already in use in California |
| Oxidation Catalyst |
None |
20%-30% |
Already in use on some vehicles |
| Urea-SCR Catalyst |
80% or more |
30% |
Prospect for availability between 2005 and 2007. Requires study of urea-loading and storage infrastructure. |
| Plasma Exhaust Treatment |
65% or more |
30% |
Presently under research |
|
From DOE Report NREL/SR-540-32689
The DOE has already studied issues related to ammonia slip and urea supply infrastructure for SCR systems. Research into the practicality of SCR is proceeding, and urea-SCR catalyzers are seen as one effective method for complying with more stringent regulation.
Large increases in urea demand are predicted for the period from 2007 to 2010 if SCR systems are practically adopted.
Diagram 3: Estimated Urea Demand
The DOE foresees continued strong demand for diesel trucks in the US, which means that it remains necessary to monitor trends in the use of SCR as a countermeasure for diesel exhaust.
Although there is still much resistance to the diesel engine in the US, the enthusiastic approach to developing the infrastructure necessary for practical use of this technology in Europe could possible envelop the US as well, and it is essential to keep a comprehensive watch on developments regarding SCR in both Europe and the US.
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9/10 |
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