Emissions improvement through fuel quality

In order to achieve its objectives with regards the limitation of CO₂ emissions, the Commission is proposing monitoring of CO₂ emissions from new passenger cars registered in a given calendar year as well as information on the manufacturer, fuel type, mass, engine power and engine capacity.

Emissions improvement through fuel quality

Continuing reductions in new car emissions reaching 95% have already been achieved by the motor industry. In order to achieve significant further reductions, enhanced fuel quality will be necessary and/or the commercial acceptance of alternative power sources (e.g. electric vehicles, hydrogen fuel cells etc.).

Cleaner fuel is an essential factor in improving ambient air quality, by reducing the level of particulates produced, and improving the performance of catalytic converters. Some engine developments aimed at improving air quality cannot be introduced unless there are significant improvements in the quality of fuel.

European Commission Directive 98/70/EC tackles the issue of quality of petrol and diesel fuel and sets a time limit (2005) for the introduction of higher quality diesel and petrol including a banning of leaded petrol throughout Member States. The Directive is an outcome of the “Auto/Oil Programme” which was a joint programme initiated in 1992 between the European Commission, ACEA and EUROPIA (European oil industry). The objective of the programme is to reduce vehicle emissions and attain air quality targets through cost-effective measures which include vehicle technology, fuel quality, improved durability and other non-technical means.

Whilst both engine development and fuel quality make an important contribution to air quality, only the latter has the potential of providing an across the board effect to the entire car parc. In collaboration with government, the UK Motor Industry has undertaken an extensive programme of research into the emission of particulates from petrol and diesel engines.

Fuel Quality impact on OBD

With regards OBD, poor fuel quality could cause MIL light operation, a situation which has been known to occur in the United States where OBD has been used for some time. When the vehicle with the active MIL light has been diagnosed, a P0300 diagnostic trouble code has been registered which would normally be associated with a lean misfire condition due to a vacuum leak, low fuel pressure, dirty injectors or an ignition problem such as fouled spark plugs, plug leads or weak ignition coils. The OBD-II diagnostics treats a 2% misfire rate on an individual cylinder as normal, but water in the fuel or variations in the fuel additives in reformulated fuel can increase the misfire rate to the point where it triggers the fault code and consequent MIL operation.

LEVs, ULEVs and ZEVs

The lowering of permitted emission levels from vehicles is being made progressively more stringent and the trend is set to continue for the foreseeable future until zero or near zero emission levels can be attained. In California, Low Emission Vehicles (LEVs) are already compulsory, whereby a percentage of all vehicles sold by a manufacturer must be low emission types.

From 1991 through 1995, the state of California offered an income tax credit to individuals and businesses for the partial costs of purchasing or converting standard fuel vehicles to low emission vehicles.