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A new tool able to deliver the local in-cylinder equivalence air fuel ratio with high temporal CA resolution is presented for SI engines. Although non-intrusive laser techniques have considerable advantages, they are inappropriate for series engines application and other measurement techniques do not have a fast enough time response. The probe presented fullfills the demand for fast local air-fuel ratio measurement with a simpler device than fast FID. Mounted at the spark plug location, it allows a completely normal running of the engine as it is integrated in a spark plug. The probe is based on hot wire anemometry technique involving catalytic oxidation of hydrocarbons on the wire.

Previous studies of in-cylinder heat transfers give numerous approaches of heat losses modelling principally compression and expansion strokes. These simulation methods are discussed showing that their accuracy during the intake stroke is neglected. Since most of the modern engines use strong structured air motion during the intake and compression strokes to both reduce consumption and reach different emissions levels targets, one may focus on in-cylinder aerodynamics and convective heat transfer coupling. The experimental velocity data acquired allow us to get an in-depth understanding of the spatial and temporal gradients of measured heat transfers in the cylinder of an internal combustion engine. Two different experimental methods have been used to investigate the in-cylinder air motion. First, near wall flow has been studied using two component local time-resolved Laser Doppler Anemometry (LDA).