Fibre optic sensor arrangements for the analysis of flame propagation in standard spark ignited multicylinder engines

摘要

A passive optical method has been developed to enable the inspection of flame propagation events in combustion chambers of spark ignited engines. The optical system accesses the combustion chamber via individual optical fibers. Each fiber transmitts the flame radiation present within its aperture, the optical signal is converted with photodiodes and is continuously recorded. For the purpose of monitoring local flame radiation properties such as flame front propagation, or localised combustion events such as diffusion burn in pool fire flames or self ignition due to knock or glow ignition, multichannel sensor arrangements are used. The multichannel arrangements are designed to have very narrow aperture cones for each individual optical fiber and geometric arrangements of the fibers which enable the reconstruction of local combustion events. These geometric arrangements cover applications for tomographic reconstruction of flame distribution and for model based event reconstruction if low resolution arrangements must be used. The fiber sensor arrays are implanted in engine components such as the cylinder head gasket or the body of spark plugs. This ensures that the sensors are not compromising the operation of a standard, multicylinder engine. The paper gives an overview of the field of application and presents application examples for engine engineering.