Gas engine piston, gas engine, gas engine operation method

A gas engine piston 10 for combusting hydrogen or hydrogen/hydrocarbon gas mixtures, the piston 10 comprising a piston body 12 and at least one heat-insulating element 14, such as a coating on the piston body, having a higher heat-insulating property than the piston body. The heat insulating property of the insulating element may be based on a predetermined parameter such as a piston cooling system, cooling oil or combustion gas. By providing the heat-insulating element low-temperature cooling oil coking that can occur when combusting lean combustion gases comprising hydrogen may be prevented. Further claimed is a gas engine 100 for hydrogen or hydrogen/hydrocarbon gas mixtures, and a gas engine operation method, comprising the steps of operating (S10, fig.7) the gas engine piston 10 with hydrogen or a hydrogen/hydrocarbon gas mixture; and observing (S20, fig.7) no low temperature cooling oil coking.