In a gas flow controlled combustion system, an in-cylinder gas stream formed by a contoured piston surface shape interacts with an oil beam. This kind of system does not spray the oil mist toward the pit of the piston, but sprays it toward the spark plug. The special shape of the inlet port and the injector are at an angle, giving the mixture a certain swirling force in the cylinder and forming in the cylinder. The air flow causes the oil and gas not to be directly sprayed toward the spark plug, but instead forms a vortex in the cylinder to rotate around the spark plug. This allows for proper mixing and homogenization of the mixed gas charge for most conditions.