A collecting exhaust port 18 provided in a cylinder head 12 is comprised of exhaust port sections 46 extending from exhaust valve bores 35 in cylinders 14, and an exhaust collecting section 47 in which the exhaust port sections 46 are collected. The cylinder head 12 includes a protrusion 49 projecting in an arch shape outside a side wall 11 1 of a cylinder block 11. The exhaust collecting section 47 of the collecting exhaust port 18 directly faces an inner surface of a side wall 12 1 of the protrusion 49. Water jackets J2 and J3 for cooling the protrusion 49 are provided in upper and lower surfaces of the protrusion 49 having the collecting exhaust port 18 defined therein. The water jackets J2 and J3 are not provided between the side wall 12 1 of the protrusion 49 and the exhaust collecting section 47. Thus, the compact cylinder head 12 having the collecting exhaust port 18 integrally provided therein can be formed, while avoiding the complication of the structure of a core.

Cylinder head structure in multi-cylinder engine

An exhaust arrangement for a multi-cylinder internal combustion engine (1) of a vehicle which has a row of cylinders (C1-C4). The arrangement includes an exhaust manifold (2) including a branch portion (8) having a plurality of branch pipes (7A-7D) corresponding to the cylinders, a catalyst (4) disposed downstream of the exhaust manifold (2), and an exhaust pipe (3) connecting the exhaust manifold (2) to the catalyst (4). The exhaust pipe (3) defines an exhaust path having a bend (12). The bend (12) includes a plane dividing an interior of the bend (12) into equal halves. A partition (14) divides the exhaust path into first and second exhaust passages (15,16) coextending in a longitudinal direction of the exhaust pipe (3). The partition (14) extends in the bend (12) in alignment with the plane. An oxygen sensor (23) is disposed at the bend (12) of the exhaust pipe (3) in alignment with the partition and projects into both of the first and second exhaust passages (15,16) through a periphery of the partition (14).

Exhaust arrangement for internal combustion engine

An exhaust manifold connected to exhaust ports of at least three straightly-arranged cylinders of an internal combustion engine is constructed by a primary exhaust pipe which extends from the foremost cylinder of the cylinders in the rearward direction of the engine along the direction of the straight arrangement of the cylinders and a plurality of secondary exhaust pipes which extend from the other cylinders except for the foremost cylinder to the primary exhaust pipe. The secondary exhaust pipes are collected to the primary exhaust pipe so that downstream end portions of the secondary exhaust pipes are wound into the center axis of the primary exhaust pipe at a plurality of points on the center axis, respectively.

Exhaust manifold for internal combustion engine

In an exhaust system, a first oxygen sensor (S1) is attached to an exhaust pipe (101) connected to a standard cylinder in which the amount of injected fuel is the closest to the average of the amounts of fuel injected in a plurality of cylinders. A controller calculates the air-fuel ratio of the standard cylinder based on the value detected by the first oxygen sensor (S1). Then, based on the difference between the calculated air-fuel ratio of the standard cylinder and a predetermined target air-fuel ratio, the amount of correction to the amount of fuel injected in the standard cylinder is determined such that the air-fuel ratio of the standard cylinder is equal to the target air-fuel ratio. Furthermore, based on the amount of correction to the amount of fuel injected in the standard cylinder, the amounts of correction of the other cylinders are determined.

Exhaust system, and engine device and vehicle with the same

An exhaust manifold provides improved output by suppressing exhaust interference between cylinders at the exhaust manifold. An air-fuel ratio sensor is installed in position where it can uniformly detect the exhaust gas of each cylinder. The exhaust manifold has a plurality of exhaust tubes, one per cylinder, that connect with a collector case. Each of exhaust tubes has a linear portion located directly above the section where it merges with the collector case. The exhaust tubes are connected to the collector case such that the center axes of the linear portions intersect at intersection point inside the collector case or downstream thereof. The air-fuel ratio sensor is arranged such that its detecting part is positioned in the vicinity of the intersection point. Depending upon whether the exhaust tubes of cylinders have firing orders that are successive or not determines whether the exhaust tubes are slanted or parallel with respect to each other.

Exhaust Manifold for internal combustion engine

An exhaust manifold comprising a plurality of exhaust pipes and a merging portion applies exhaust gas from each cylinder uniformly to an oxygen sensor in a merging portion at low speed thereby improving the durability of the oxygen sensor. A downstream forward end of each exhaust pipe of the exhaust manifold, when connected to an inlet wall of a merging case having the oxygen sensor mounted on a side thereof, is formed in the shape of a bell mouth for leading the exhaust gas to the oxygen sensor. Each exhaust pipe is fixedly welded to the merging case at a position upstream of the forward end of the bell mouth. An angle formed by lines perpendicular to tangential lines at starting and ending points of a curved portion of the bell mouth at the forward end of the exhaust pipe is set in the range of 45° to 75°. As a result, the bell mouth spreads over the whole interior of the merging case and reduces a flow rate of the exhaust gas, and part of the exhaust gas flows toward the oxygen sensor. The oxygen sensor is thus more evenly exposed to the exhaust gas and has increased durability.

Exhaust manifold, for internal combustion engine, for improving durability of oxygen sensor at merging portion of exhaust manifold

PROBLEM TO BE SOLVED: To improve gas hitting property without damaging durability of an oxygen sensor inside an aggregation with regard to an internal combustion engine exhaust manifold composed of a plurality of exhaust pipes and aggregations. SOLUTION: When an individual downstream side end 1A of a plurality of exhaust pipes 1 is connected to an inlet side wall 2A of an aggregation case 2 having an oxygen sensor 3 mounted on its lateral, the form of the exhaust pipe 1 ends 1A is made in a bell-mounth shape for guiding exhaust gas to the oxygen sensor 3. Respective exhaust pipe 1 is preferable to be fixed to the aggregation case 2 by welding at the upper stream position than the bell-mouth shaped end 1A. In this case, the angle formed by the starting part of the curve of the bell-mouth shape of the exhaust pipe end 1A and the end part is preferable to be within the range from 45 deg. to 75 deg.. Thus because exhaust gas is wholly diffused by the bell-mouth shape and its flow velocity weaken and a part of the exhaust gas flows towards the oxygen sensor 3, exhaust gas hitting the oxygen sensor 3 is improved without deteriorating the durability of the oxygen sensor 3.

Oi Yasuhiro

Papers

Exhaust manifold, for internal combustion engine, for improving durability of oxygen sensor at merging portion of exhaust manifold

Internal combustion engine exhaust manifold