Engine system

An engine system in which blow-by gas with a specific gravity less than 1 with reference to air is generatable, the engine system comprising:

• a cylinder block including a cylinder and a crank chamber which are arranged in an up/down direction, the crank chamber being positioned below the cylinder,
• wherein
• an internal peripheral face of the cylinder block has a ventilation port that is open and connects to a ventilation passage that connects an internal space of the crank chamber with an external space outside of the cylinder block,
• the ventilation port is placed above a center in the up/down direction of the crank chamber,
• an internal peripheral face of the cylinder block has a gas introduction port that is open and connects the internal space of the crank chamber with the external space out of the cylinder block, and
• the engine system further comprises an airflow forming portion that forms an airflow from the gas introduction port toward the ventilation port,
• in an output axis direction along a rotational axis of a crankshaft placed in the crank chamber, the ventilation port and the gas introduction port are placed at positions different from each other,
• the cylinder includes multiple cylinders provided to be arranged in the output axis direction,
• the multiple cylinders include a one end side cylinder and another end side cylinder which are positioned on both sides of the multiple cylinders in the output axis direction,
• the ventilation port is placed at a position that corresponds to the one end side cylinder, and
• the gas introduction port is placed at a position that corresponds to the other end side cylinder.