Nitrogen oxides in internal combustion engine gases
An account was given in a paper entitled “Proknocks and Hydrocarbon Combustion” (Ubbelohde, Drinkwater and Egerton 1935) of some experiments made to trace the source of the nitrogen peroxide which had been found by sampling the products from the cylinder of a petrol engine at various stages of the stroke. Those experiments indicated that it was not simply a matter of nitric oxide formed by the flame giving rise to the nitrogen peroxide, for different results were obtained using different exhaust-valve surfaces. Nevertheless it seemed probable that the flame should be mainly responsible for the formation of nitric oxide, and so further experiments have been made. In order to make progress it was essential to determine the amount of nitric oxide as well as the amount of nitrogen peroxide, and analytical methods had to be devised to do this. The first part of this note deals with the methods of determining small quantities (of the order of 10 -4 mol. fraction) of total nitrogen oxides and of nitrogen peroxide, and the second part with the results of analyses of the gases sampled from the cylinder of internal combustion engines by the methods described by Egerton, Smith and Ubbelohde (1935) and by Drinkwater and Egerton for the C. I. engine in a paper shortly to be published.