Search Results

An acknowledged consequence of utilising oxygenates such as MTBE as a gasoline component is known to be a lowering of CO exhaust emissions from mature technology vehicles due to the “natural” leaning effect that the inclusion of MTBE can provide. A small decrease in THC is also commonly seen in these circumstances, while the effect of MTBE on NOx emissions is more variable and not usually beneficial. The present paper describes the results of recent studies in the European arena, covering the effects of fuel oxygenates (notably MTBE) on regulated emissions for non-catalyst and catalyst car fleets examined in in-house programmes. It looks at emissions effects according to the broad classification of the onboard vehicle technology employed. It further cites experimental work that has featured MTBE replacement in gasolines by a single saturated hydrocarbon (2,3-dimethyl butane) that is isoelectronic with MTBE. Some related work conducted concurrently on splashblending is also described.

Europe is currently on the threshold of introduction of unleaded gasoline. However, this will not proceed uniformly, as some countries such as Germany. Austria. Switzerland and now Scandinavia are moving much more quickly than others. In those countries where unleaded fuel is available, registrations of catalyst cars and the build-up of the gasoline retail network and sales volumes are described. Possible future developments in these areas are discussed. The potentials and limitations on the manufacture of unleaded gasoline are discussed together with the role of oxygenates. The development of specifications in various countries is described and on the basis of market surveys actual quality is compared with the minimum requirements of these specifications. Results of road tests are presented showing the effects of both gasoline with maximum lead content and engine oil with a relatively high phosphorous content on deterioration of catalyst efficiency.