Exhaust emissions and odors from 140 Helsinki city buses were significantly reduced in a year long test of low sulfur diesel produced by the oil division of Neste Corp.
Compared with buses using conventional diesel fuel, Neste Oil and Helsinki City Transport (HCT) found buses powered by Neste Oil's City Diesel fuel generated:
- 97-99% less sulfur emissions.
- 2-10% less nitrogen oxide emissions.
- 10-30% less particle emissions.
- 50% less smoke when started in cold weather.
Buses using City Diesel consumed 2% more fuel than buses using normal diesel.
Maintenance and repair of buses using City Diesel were unchanged.
City Diesel, developed after 1989 by Neste and two Swedish bus manufacturers, contains 0.005 wt % sulfur. It also has lower levels of aromatic compounds and less combustible hydrocarbons than conventional diesel blends and costs about 7/gal more to produce, Neste said.
Conclusions were based on bus exhaust data generated in 1991 by a study of bus emissions by Neste, HCT, the State Technical Research Center of Finland (VTT), and Finland's Ministry of Trade & Industry (MTI). Funding was provided by an energy and environmental technology program of MTI.
Research aimed at cutting bus exhaust emissions is to continue to the end of 1993 under a project by Neste, HCT, VTT, and Kemira SA/NY, Brussels. Researchers also will study effects on health of vehicle exhaust emissions.
Neste said City Diesel can be used in all diesel engines and can be stored and dispensed by the same types of equipment as normal diesel fuel.
"Improvements in engine technology likely will reduce exhaust emissions over the long term," Neste reported.
"But using City Diesel opens the possibility of achieving immediate improvements with existing vehicles."
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