Abstract
In designing an after-burner it was decided to use the California emission test cycle since this was the only recognized test standard. It also gave a fair coverage result, but for British conditions a modified cycle with longer idling and 15 mile/h cruising periods was used.
Experience in gas turbine design was invaluable in tackling this design problem. Modern American automobiles have carbon monoxide emissions of 1·5–4 per cent when measured over the standard test cycle, but on some European vehicles 3–5·5 per cent has been observed.
The dimensions of the after-burner had to be restricted to the available space in cars, and designed as simply as possible. Prototypes were made and extensive testing carried out. Eventually a satisfactory unit was produced with good performance on the road. The reduction in pollution was very satisfactory and values for the Californian cold test procedure were 1·5 per cent carbon monoxide and 100 parts per million hydrocarbons.
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