Search Results

The benefits of diesel fuel additives have been demonstrated in a broad range of performance and operational areas, from the refinery, through storage and distribution, to fuel dispensing and vehicle operation. The customer is certainly aware of their effects on fuel performance in many of these respects, such as cold-weather operation, ease of starting, foaming, odour, etc. An area of particular interest in customer perception, however, is fuel economy. Excluding the use of after-market fuel-treatment devices, it is claimed that additives of different types can improve fuel economy, for example by improving combustion, by maintaining injection equipment in optimum condition, or by reducing engine frictional losses.

A method is proposed to quantify the activity of a detergent at a selected engine operating condition by measuring the amount of additive required to reduce nozzle fouling to zero in a well-defined engine test procedure. To determine this critical detergent concentration, a series of engine tests is performed using increasing levels of additive, until a zero level of fouling is achieved. These results are then used to construct a detergent concentration response map, defining unambiguously the additive activity and allowing quantitative comparisons of different detergents or additive packages. Concentration response plots are presented from both bench engine test series and vehicle road trials which demonstrate the wide variability in the amount of different detergents required to achieve comparable deposit control. From these maps the performance of the detergents may be compared in terms of keep-clean and clean-up activity for the range of engines and operating conditions.