Laser Spark Plug for Ignition of Fuel Mixtures in Thermal Engines

A compact laser spark for ignition of gaseous fuel mixtures has been designed and implemented. The monolithic Nd:YAG/Cr:YAG passively Q-switched laser chip with fiber-coupled diode end pumping is considered as a laser pulse generator. With help of numerical simulation, optimal resonator parameters were found to ensure the greatest efficiency of optical conversion. The following parameters of the laser spark output pulses are obtained: energy of 2.71 mJ and duration of ~0.6 ns, peak power density in focus ~1.5 GW/cm
²
. The construction of laser spark plug ensures resilience to high mechanical and thermal loads at operation. Possibility of gaseous mixtures ignition with this spark plug has been evaluated experimentally.