_pg clean but dear

18th October 1980, Page 27

18th October 1980

Page 27

Page 27, 18th October 1980 — _pg clean but dear

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'ALUATION of a double-deck bus powered with liquid petroleum s has shown that the bus is cleaner and quieter than a convennal diesel, but much more expensive to run.

d Shell UK Oil.

The Leyland-engined bus was mpared with an identical dieI bus over the same route and 1ring its first 18,000 service Iles it returned only 3.6mpg mpared with the 7.4mpg rered by the conventional hide.

The Carlisle bus needed an adnced fuel storage and control stem and this was installed th a minimal amount of alterain to the basic vehicle layout Ribble staff and Landi Hartog K) Ltd.

The engine used was a Leyid 680, normally fitted to the lantean but converted to spark nition for lpg fuel by Leyland thicles with assistance from e TNO Research Institute for lands.

The engine performance was test-bed set to keep the maximum exhaust temperature no higher than the diesel version.

Initial reports from the trials have revealed a satisfactory performance from the bus engine which produces good low-speed torque and reduced internal noise and vibration. External noise levels were predictably similar to the standard powered vehicles. But noise levels of the diesel bus did get worse while the vehicle was in service but the lpg-powered vehicle stayed quieter.

Ribble is to continue with its evaluation and is using NBC's Vehicle Maintenance Costing system which should allow detailed cost assessments of the two types of vehicles.

The National Bus Company is not extending the evaluation to convert further vehicles as operating costs are of crucial importance and neither research nor financial assistance is available to offset additional fuel and conversion costs.