Patent ID: 7619742

Claim:
A high-speed spectrographic sensor for internal combustion engines comprising: a plug receivable into a combustion chamber of an operating internal combustion engine; a light source providing light at multiple frequencies having wavelengths less than 3000 nm; a light guide held by the plug and receiving the light source to communicate the light into the combustion chamber for interaction with combustion gases and to communicate the light out of the combustion chamber for sensing; and a sensor system including a slit-less spectroscope receiving light from the light guide, the slit-less spectroscope attached to the light guide to receive light from the light guide directly also without an intervening slit; the spectroscope distinguishing strength of no less than 20 multiple frequencies of the light at a rate of no less than 1000 times per second after interaction with the combustion gases; wherein the spectroscope provides an optical system spatially separating multiple light frequencies as received simultaneously from the light guide after passage through the combustion chamber to permit simultaneous monitoring of the multiple frequencies at different spatial locations.