At the same time, Volvo also worked intensively on emission control, trying to control the unregulated oxidizing catalyst that was going to be introduced soon and to make it - under certain conditions - reduce the three harmful substances hydrocarbons (HC), carbon monoxide (CO) and nitric oxides (NOX) to negligible levels. By improving the exhaust cleaning capacity through controlling the fuel/air mixture in the narrow band where the ratio for the catalyst is at its optimum, in 1976, Volvo became the first car manufacture to serve the solution: The Lambda sensor. This genial little piece of engineering enabled the catalyst to cut more than 90 per cent of the harmful hydrocarbon, carbon monoxide and nitric oxide levels that are created as a result of the combustion of the fuel/air mixture.
The year after, California introduced new stricter maximum levels for these substances (hydrocarbons 0.41 g/mile; carbon monoxide 9.0 g/mile; nitric oxides 1.5 g/mile) which by then were the strictest in the world. Volvo cars using three-way catalysts and Lambda sensor emitted considerably less than these levels. The emissions of nitric oxides were very low and as a consequence, Volvo was awarded for its pioneering work by the Carter administration.
The year after, California introduced new stricter maximum levels for these substances (hydrocarbons 0.41 g/mile; carbon monoxide 9.0 g/mile; nitric oxides 1.5 g/mile) which by then were the strictest in the world. Volvo cars using three-way catalysts and Lambda sensor emitted considerably less than these levels. The emissions of nitric oxides were very low and as a consequence, Volvo was awarded for its pioneering work by the Carter administration.