As carmakers try to reduce the harmful emissions from gasoline-powered engines, efforts focus on controlling engine performance using data from sensors. A team from Texas A&M University in College Station and Fiber Dynamics Inc. in Bryan, Texas, has integrated a fiber optic sensor and a spark plug to provide in-cylinder pressure information.

The researchers demonstrated sensitivities as high as 0.00339 rad/psi using the intrinsic fiber Fabry-Perot interferometer, as described in the Feb. 20 issue of Applied Optics. Monitoring the pressure on the sensors, they employed a semiconductor laser emitting near 1300 nm to measure changes in the reflectance of the metal-coated fiber.