Abstract: A blow-by gas recirculation structure includes a cylinder head including an intake manifold mounting surface and a cylinder block mounting surface with a first intake passage extending between a first intake opening formed in the intake manifold mounting surface and a first intake port formed in the cylinder block mounting surface, and a second intake passage extending between a second intake opening formed in the intake manifold mounting surface and a second intake port formed in the cylinder block mounting surface. The cylinder head further includes at least one blow-by gas passage for recirculating blow-by gas to the first intake passage. The intake manifold mounting surface has at least one enlarged recess fluidly connected between the blow-by gas passage and the first intake passage, the enlarged recess being disposed between the first and second intake openings and at least partially aligned with centers of the first and second intake openings.

Abstract: A blow-by gas recirculation structure for an engine includes a gas-liquid separating member, a cylinder head, a support member and a mounting bolt. The gas-liquid separating member includes a gas-liquid separating passage to separate oil from the blow-by gas. The cylinder head includes a communication passage communicating with the air intake system. The support member is configured and arranged to rotatably support a camshaft in the cylinder head. The mounting bolt securely fastens the support member to the cylinder head with the mounting bolt threadedly engaging within the communication passage of the cylinder head. The mounting bolt has an axial through hole axially extending there-through and communicating with the gas-liquid separating passage so that the blow-by gas that has passed through the gas-liquid separating passage is recirculated from the axial through hole of the mounting bolt, through the communication passage, and into the air intake system.

Abstract: A cam lobe of a camshaft has a base circle portion and a lifting lobe portion. A camshaft journal of the camshaft has first and second bearing portions that bear reaction forces from the base circle portion and the lifting lobe portion, respectively. The first bearing portion has an axial width smaller than that of the second bearing portion with at least a portion of an axial end surface of the first bearing portion facing the cam lobe being disposed away from the cam lobe relative to an axial end surface of the second bearing portion. The base circle portion has an axial width smaller than that of the lifting lobe portion with at least a portion of an axial end surface of the base circle portion facing the camshaft journal being disposed away from the camshaft journal relative to an axial end surface of the lifting lobe portion.

Abstract: A blow-by gas recirculation structure includes a cylinder head including an intake manifold mounting surface and a cylinder block mounting surface with a first intake passage extending between a first intake opening formed in the intake manifold mounting surface and a first intake port formed in the cylinder block mounting surface, and a second intake passage extending between a second intake opening formed in the intake manifold mounting surface and a second intake port formed in the cylinder block mounting surface. The cylinder head further includes at least one blow-by gas passage for recirculating blow-by gas to the first intake passage. The intake manifold mounting surface has at least one enlarged recess fluidly connected between the blow-by gas passage and the first intake passage, the enlarged recess being disposed between the first and second intake openings and at least partially aligned with centers of the first and second intake openings.

Abstract: A blow-by gas recirculation structure for an engine includes a gas-liquid separating member, a cylinder head, a support member and a mounting bolt. The gas-liquid separating member includes a gas-liquid separating passage to separate oil from the blow-by gas. The cylinder head includes a communication passage communicating with the air intake system. The support member is configured and arranged to rotatably support a camshaft in the cylinder head. The mounting bolt securely fastens the support member to the cylinder head with the mounting bolt threadedly engaging within the communication passage of the cylinder head. The mounting bolt has an axial through hole axially extending there-through and communicating with the gas-liquid separating passage so that the blow-by gas that has passed through the gas-liquid separating passage is recirculated from the axial through hole of the mounting bolt, through the communication passage, and into the air intake system.

Abstract: A cam lobe of a camshaft has a base circle portion and a lifting lobe portion. A camshaft journal of the camshaft has first and second bearing portions that bear reaction forces from the base circle portion and the lifting lobe portion, respectively. The first bearing portion has an axial width smaller than that of the second bearing portion with at least a portion of an axial end surface of the first bearing portion facing the cam lobe being disposed away from the cam lobe relative to an axial end surface of the second bearing portion. The base circle portion has an axial width smaller than that of the lifting lobe portion with at least a portion of an axial end surface of the base circle portion facing the camshaft journal being disposed away from the camshaft journal relative to an axial end surface of the lifting lobe portion.

Abstract: An apparatus for circulating a blowby gas to engine cylinders in an internal combustion engine, including a cylinder head cover including a first wall defining a first passage, and a first flange outwardly extending from the first wall, and a cylinder head including a second wall and a second flange cooperating with the first flange to form an abutting surface therebetween on which a second passage is arranged. The second passage is connected with the first passage and extending in a direction of a row of the engine cylinders. The second wall defines a plurality of third passages each having one end that is open to the second flange and communicated with the second passage and an opposite end open to an intake port of each of the engine cylinders.

Abstract: An apparatus for circulating a blowby gas to engine cylinders in an internal combustion engine, including a cylinder head cover including a first wall defining a first passage, and a first flange outwardly extending from the first wall, and a cylinder head including a second wall and a second flange cooperating with the first flange to form an abutting surface therebetween on which a second passage is arranged. The second passage is connected with the first passage and extending in a direction of a row of the engine cylinders. The second wall defines a plurality of third passages each having one end that is open to the second flange and communicated with the second passage and an opposite end open to an intake port of each of the engine cylinders.

Abstract: A mounting structure is provided for an EGR valve or an EGR tube. The EGR valve or the EGR tube is made of stainless steel or cast iron which is high in the physical strength at a high temperature. The EGR valve or the EGR tube is mounted to an intake manifold made of aluminum by means of bolts or stud bolts. The EGR valve or the EGR tube has female threads provided therein into which the bolts or stud bolts are screwed. The intake manifold has through holes provided therein through which the bolts or stud bolts extend.

Abstract: In order to minimize the supercharging effect from the cylinder to cylinder and to maximize the efficiency of the inertia supercharging effect over essentially the whole engine speed range, first and second elongate collectors which communicate with separate banks of cylinders are interconnected at essentially their mid points by a connection tube having a selected length and cross-sectional area. An engine speed responsive valve disposed in the tube or pipe selectively induces the situation wherein quasi separate induction systems are defined for each bank of cylinders or a single enlarged system is established.

Abstract: In order to minimize the supercharging effect from the cylinder to cylinder and to maximize the efficiency of the inertia supercharging effect over essentially the whole engine speed range, first and second elongate collectors which communicate with separate banks of cylinders are interconnected at essentially their mid points by a connection tube having a selected length and cross-sectional area. An engine speed responsive valve disposed in the tube or pipe selectively induces the situation wherein quasi separate induction systems are defined for each bank of cylinders or a single enlarged system is established.