Search Results

The accurate confirmation of fuel economy benefits arising from the use of a gasoline additive package is a difficult exercise. In order to fully understand, and accurately quantify, the interaction between the treated fuel and the engine it is necessary to carry out a fleet test which allows the benefit to be measured precisely yet under realistic conditions. A series of road tests, based on a ‘paired fleet’ design, has been carried out over the last two decades. Careful analysis of the results of these tests has led to the design of a new fleet testing protocol based around ‘quads’ rather than pairs of vehicles. This new test protocol also incorporates advances in vehicle selection and preparation procedures and has resulted in a test that is both more robust and flexible, and that achieves even better resolution than before.

In Europe, the development and implementation of new regulatory test procedures including the chassis dynamometer (CD) based World Harmonised Light Duty Test Procedure (WLTP) and the Real Driving Emissions (RDE) procedure, has been driven by the close scrutiny that real driving emissions and fuel consumption from passenger cars have come under in recent times. This is due to a divergence between stated certification performance and measured on-road performance, and has been most pointed in the case of NOx (oxides of nitrogen) emissions from diesel cars. The RDE test is certainly more relevant than CD test cycles, but currently certification RDE cycles will not necessarily include the most extreme low speed congested or low temperature conditions which are likely to be more challenging for NOx after-treatment systems.