EC limits set
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1111 Exhaust emissions limits for diesel-engined trucks and buses have been agreed by the EC Environment M in isters.
This will limit carbon monoxide to 4.5g/kWh: hydrocarbons to 1.1g/kWh: nitrous oxides to SWAM: and particulates to 0.63g/kWh for engines below 85Kw (114 Ii p1 and 0.36 for larger engines.
These limits will apply lo vehicles seeking type approval after July 1992 and vehicles in production by October 1993.
By October 1995 vehicles corning off the pniduclion lines will have emission limits of: CO, Lkg/kWh; RU. 1.10Wh NoX,
7g/kWh: and particulates. (1.15g/kn.
Ft is almost certain that Ihese levels will force truck manufacturers to fit electronic controls to diesel injector pumps, says Ricardo Consulting Engineers.
Cummins already has 'Celect Electronic versions of its 10 and 14-litre engines running in the US. and version of these may be used in Europe to ifleet the regulations.
Tests indicate that 40% of particulates from a DI diesel come from the lubricating oil. To achieve tlw limit of 0.15g/kWh American and European engine manufacturers are taking different approaches.
The Americans tend to favour oils with low additive levels. allowing for some to get into the combustion chamber and cause particulates. These oils will have to be changed more frequently and oil drain periods may have to come down.
In Europe the engine manufacturers are counting on 'super performance' synthetic oils to solve the problem. These will be expensive, but drain periods may well be extended. At least one oil company is reviewing its policy of saying that its oil is suitable for all diesel engines.
Vehicles will be checked for emissions at annual plating, although the equipment and procedures are as yet unclear. It is also possible that roadside checks may be carried out.