Abstract: Sensor apparatus for a multiple layer steel (MLS) cylinder head gasket measures combustion pressures for detecting engine conditions. A membrane is positioned at one end of an elongated metal tube, and the membrane end of the tube engages a cylinder bore boundary. A fiber optical sensor apparatus is fixed within the tube, and communicates with cyclic combustion events via the membrane. In one disclosed embodiment, optical wires from sensor apparatus situated at each engine bore are bundled into a common groove machined into an extended spacer layer radially outwardly of the conventional boundary of the gasket. The tube protects the sensor apparatus from damage of sealing stress on the gasket, and particularly at the bore perimeter. Each tube lies in a separate groove in the spacer layer that terminates at the bore boundary. A converter changes optical signals received from the apparatus into electrical signals for transmittal to a controller.

Abstract: A multi-layer steel (MLS) cylinder head gasket containing fully integrated pressure sensors includes first and second metal layers with inner facing surfaces, and a spacer layer interposed between the facing surfaces. Outer (non-facing) surfaces of the first and second metal layers each include an elastomeric seal coating; the inner surfaces of the layers each include a friction reducing coating. Combustion apertures extend fully between the outer surfaces of the gasket, and are adapted to circumscribe cylinder bores of an engine. The spacer layer includes protective slots positioned adjacent each of the combustion apertures. Each slot wall contains a pressure sensor in form of a strain gauge to measure deflection of the wall resulting from pressure changes within engine combustion chambers. The measured deflections are correlated to actual pressures within the chambers. In the protective slots, the strain gauges are not exposed to combustion gases that could otherwise foul the sensors.