Patent ID: 8215284

Claim:
A micro-pilot injection ignition type gas engine that ignites and burns premixed air fuel-gas mixture inducted into each main combustion chamber, by means of at least one pilot flame that jets out from a pre-chamber to the main chamber through at least one pre-chamber nozzle hole communicating the main chamber to the pre-chamber in which a fuel-oil injector injects micro-pilot fuel oil to produce a pre-chamber combustion gas as a source of the flame jet, the gas engine comprising: a gas valve that delivers and cuts a fuel-gas at a position in front of each cylinder, so as to arbitrarily control the throat area as well as an opening-or-closing time span of the gas valve; an engine speed detecting unit to detect the engine speed; a cylinder pressure sensor provided at each cylinder so as to continually measure pressure levels as to each cylinder; a combustion diagnosis unit to monitor the pressure levels so that the diagnosis unit analyzes an engine combustion state through a cylinder pressure distribution along elapsed time, the distribution as to each cylinder being formed in the diagnosis unit; an opening-closing control unit as to the gas valve, so as to control an intermittent opening-or-closing of the gas valve in response to the engine speed and the pressure distribution; whereby, in starting the engine, the intermittent opening-or-closing of the gas-valve enables at least one skip-firing mode that brings an enhanced fuel-supply pressure-pulsation with which an increased amount of fuel-gas is supplied per one engine-cycle with firing so that the air fuel-gas ratio of each cylinder reaches a prescribed target value.