Cylinder Head Gasket With Integrated Miniature Combustion Pressure Sensors

The design and preliminary performance of a multi layer metal cylinder head gasket with integrated 1.7mm diameter combustion pressure sensors is described. The pressure sensors are either removable from the gasket without need for engine head removal or permanently fixed to the gasket. The gasket design is suitable for all sizes and types of internal combustion engines including gasoline, diesel, or alternative fuel, with peak pressures ranging from 100bar to 350bar. The sensors’ diaphragms are positioned semi-flush with the gasket surface exposed to combustion gasses while the sensors’ sealing surfaces are located 5mm-7mm from the diaphragms. The devices miniature signal conditioners are mounted inside a gasket extension protruding beyond the engine block. The miniature fiber optic pressure sensor operates on the principle of light intensity changes transmitted by two fibers upon reflection from a metal diaphragm deflecting under the effect of cylinder pressure. Preliminary test results are reported here collected on a 4-cylinder gasoline engine demonstrating good agreement with a reference transducer. When optimized, it is expected that a gasket integrated sensor will offer the accuracy of +/-1.5% enabling advanced engine controls based on Indicated Mean Effective Pressure (IMEP), Mass Fraction Burned (MFB), Peak Pressure as well as control of pilot fuel injection and virtual Mass Air Flow and NOx sensing.