Measuring vibrations on an engine manifold

An internal combustion engine demands continuos optimization of processes. For this, a whole series of engine management operations are required. This includes temperature measurement of the exhaust gas that is done using a thermocouple within the manifold and examining the propensity to vibrate in the comubustion engine. It is also important to examine the way the combustion engine is attached  and the mechanical rigidity of the structure. To perform this kind of measurement, blue laser sensors are incorporated.

The high-temperatures in the flow of exhaust gas leads to the thermcouple self-fluorescing, due to which short wavelength of the blue-violet laser provides decisive advantage. Because of the short wavelength, the light emitted from the thermocouple does not dazzle the sensor and is effectively blocked by the high quality interference filters used.

The blue laser consists of a narrow slit that provides the free space needed for the optics. To prevent the high temperatures from affecting the measurement, a protective plate is featured in the laser sensor that reduces the temperature while operation. Meanwhile, a blower featured by the sensor enables clean optical conditions and the required cooling. The fast sampling frequency allows for the vibrations to be recorded accurately and the evaluations can be performed via an interface to the PC.