Standards raised to win fares
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• Passenger transport exhibits at the recent Transport '90 show in Munich reflected the concern of industry and operators to raise standards of PSV equipment and services to offer an attractive alternative to the private car. On the environmental front, there are signs that the use of particulates filters in PSV operation is not the panacea it was once thought to be: work being carried out by MAN is just one example of a different approach to exhaust emission problems. Particulates filters currently available have an undesirable back pressure effect when used with turbocharged engines, and the MAN theory, now under experiment in a standard Nuremberg city bus, is based on the use of low-sulphur diesel fuel, high injection pressure and an oxidation catalyst in the exhaust line. Trials have already yielded a dramatic reduction of soot/ particulates, NOx and unburnt hydrocarbons as well as almost eliminating exhaust smell.
The principle works on raising injection pressure to over 1,200 bar and use of a catalyst of the type already tested in methanol-powered engines. It requires fuel with sulphur content reduced to 0.05% — current level is 0.2% and MAN expects to meet the US 1994 limits with ease. This low-sulphur fuel is being produced for the experiment by an independent company but it is possible that the oil industry could switch to largescale production within three or four years. The extra cost to the consumer would not be more than 0.7p/lit.
An MAN-powered Van Hool A.508 midibus on show is part of the first German order for this type of vehicle. The 2.25m-wide 18-seater with room for 40 standees, is destined for a new demandresponsive service.
An innovative exhibit from Mercedes-Benz was styled and built by Duvedec of the Netherlands, using a frontwheel drive MB100 running gear. The two-door minibus is based on a steel chassis, tandem-axle extension and has aluminium-framed GRP lowfloor bodywork for 15-22 passengers.