Abstract: A blow-by gas recirculation device that, while having a structure in which a passage for blow-by gas is in a head cover and an oil separator, an increase in size of an engine is suppressed and the risk of the freezing is mostly avoided by shortening the length of an external pipe for the blow-by gas. Therefore, the blow-by gas recirculation device guides blow-by gas from a crankcase to an intake passage through an in-cover gas passage formed inside a head cover. An oil separator that traps and removes oil from the blow-by gas is attached to the inside of the head cover. A pressure regulating valve is provided on the outlet side of the in-cover gas passage in the head cover. A separator outlet, which is an outlet for the blow-by gas in the oil separator, is overlapped on a blow-by gas inlet portion of the pressure regulating valve.

Abstract: A blow-by gas recirculation device that, while having a structure in which a passage for blow-by gas is in a head cover and an oil separator, an increase in size of an engine is suppressed and the risk of the freezing is mostly avoided by shortening the length of an external pipe for the blow-by gas. Therefore, the blow-by gas recirculation device guides blow-by gas from a crankcase to an intake passage through an in-cover gas passage formed inside a head cover. An oil separator that traps and removes oil from the blow-by gas is attached to the inside of the head cover. A pressure regulating valve is provided on the outlet side of the in-cover gas passage in the head cover. A separator outlet, which is an outlet for the blow-by gas in the oil separator, is overlapped on a blow-by gas inlet portion of the pressure regulating valve.

Abstract: The present invention provides a multi-cylinder engine capable of inhibiting an EGR cooler from being damaged and at the same time making the EGR cooler compact. On the assumption that a direction where a crank shaft spans is taken as a front and rear direction and a widthwise direction of a cylinder head perpendicular to this front and rear direction is deemed as a lateral direction, an intake-air distributing passage wall is attached to one lateral side surface of the cylinder head and an exhaust-gas converging passage wall ached to the other lateral side of the cylinder head, the exhaust-gas converging passage wall having an interior area communicated with an interior area of the intake-air distributing passage wall through the EGR cooler. In this multi-cylinder engine, an intake-air inlet pipe is made to stand up at an upper portion of the intake air distributing passage wall and the EGR cooler is above the intake-air distributing passage wall.

Abstract: The present invention provides a multi-cylinder engine capable of inhibiting an EGR cooler from being damaged and at the same time making the EGR cooler compact. On the assumption that a direction where a crank shaft spans is taken as a front and rear direction and a widthwise direction of a cylinder head (2) perpendicular to this front and rear direction is deemed as a lateral direction, an intake-air distributing passage wall (3) is attached to one lateral side surface of the cylinder head (2) and an exhaust-gas converging passage wall (4) is attached to the other lateral side of the cylinder head (2), the exhaust-gas converging passage wall (4) having an interior area communicated with an interior area of the intake-air distributing passage wall (3) through the EGR cooler (6). In this multi-cylinder engine, an intake-air inlet pipe (5) is made to stand up at an upper portion of the intake-air distributing passage wall (3) and the EGR cooler (6) spans above the intake-air distributing passage wall (3).