Fibre Optics For Monitoring Internal Combustion Engines

Fibre optics can offer several advantages for sensing applications in vehicles. Electromagnetic immunity is very attractive for both data transmission and sensing applications, particularly in the region of the engine compartment. Fibre optics will have their greatest impact where their use enables engine parameters previously inaccessible to be monitored. This paper discusses the application of fibre optics to various aspects of internal combustion engine monitoring including combustion sensing and in-cylinder pressure measurement. Analysis of intensity of the light emitted from combustion of the fuel in the cylinder allows a number of parameters of combustion to be measured and experimental results are presented. Fibre optics provide a remote sensing ability which allows the detection and processing electronics to be mounted in a less hostile environment. A fibre optic pressure sensor is described that offers a simple low cost device providing another useful combustion parameter.