Coke scraping ring, cylinder liner, cylinder, gas engine and gas engine operation method

A coke scraping ring, for a cylinder liner of a cylinder used in a gas engine, the coke scraping ring for scraping carbonaceous residuals off a top land of a piston of the gas engine, the coke scraping ring comprising:

• a ring body having a top end, a bottom end, and a combustion-facing side configured to be in direct contact with combustion products during operation;
• a scraping ring section at the bottom end and a recess ring section, the recess ring section configured to provide a recess in the combustion-facing side;
• recess elements partly or fully protruding into the ring body;
• and
• wherein the recess elements have a rounded rectangular cross-section, wherein the recess elements are oriented on the combustion-facing side in a vertical, parallel and tilted, or in a zig-zag configuration.

A gas engine operation method comprising continuous scraping carbonaceous residuals off a top land of a cylinder piston, the method comprising:

• assembling a cylinder piston, a coke scraping ring, a cylinder liner, a cylinder crank case and a cylinder head to obtain a ready-to-operate cylinder;
• wherein the coke scraping ring comprises:
• a ring body having a top end, a bottom end, and a combustion-facing side configured to be in direct contact with combustion products during operation;
• a scraping ring section at the bottom end and a recess ring section, the recess ring section configured to provide a recess in the combustion-facing side;
• operating the cylinder while scraping excess carbonaceous residuals off the top land of a cylinder piston;
• and
• observing no pressure-induced deformation on the cylinder piston.