Analysis of CO Emission Sources in Diesel Combustion (Third Report)

- CO Reduction Techniques and its Validation -

Abstract

CO emission sources from diesel combustion with multiple fuel injections were analyzed by using in-cylinder CO-LIF imaging and numerical simulation. The major source of CO emission under low-load conditions is the over-diffusion of pilot sprays, and that under high-load condition is the shortage of oxygen in the rich regions at the frame front. As an example of CO reduction techniques, a new piston-cavity with a stepped lip which reduces the squish flow velocity was introduced. Its effects on CO emission were validated by exhaust emission tests and simulations.