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This paper describes the design and operation of a facility capable of providing experimental data on the mechanism of soot formation and oxidation under controlled sustainable conditions. The central piece of the facility “the combustor” is described in detail together with its variable geometry which facilitates independent control of pressure (up to 100 bar), air-fuel ratio, swirl, angled injection, fuel-wall impingement and the feasibility of intermittent injection and auto-ignition. A planned staged programme for carrying out an extensive research study is outlined, and the versatility of the installation and its usefulness for testing alternative fuels is demonstrated.

Performance and emissions data for a four-cylinder diesel engine operating with diesel fuel, vegetable oil and emulsions of these with 10 percent water are compared with data for a laboratory single-cylinder engine. Neither the lower Cetane Number of the vegetable oil nor its emulsification with water presented obstacles to operation of the commercial engine at the higher operating speed. For this engine ignition delays were similar for all test fuels. and operation was leaner, thermal efficiency higher and NOx and smoke levels lower, for vegetable oil. These emission levels were further reduced for this fuel by emulsification.

The results of steady-flow combustion tests for emulsions of 5, 10 and 20% by volume of water at two pressures are compared with those obtained with diesel oil. A reduction in CO, H/C and soot concentrations are obtained with increase in water content. Results from a single cylinder 4-stroke diesel engine show a significant reduction in NOx emissions. Photographic examination of the burning spray for different water in diesel emulsions at atmospheric pressure indicates that an increase in water content increases the rate of combustion and reduces the luminosity of the flame up to a critical value of water content.