Methods and systems are provided for a 2-port integrated exhaust manifold for an inline-3, inline-6, V-6, and/or V-12 engine. In one example, a system may include an exhaust manifold integrated within a cylinder head of an engine block. The integrated exhaust manifold may include a first set of two runners from a first outer cylinder coupled to a first manifold exhaust port, a second set of two runners of a second outer cylinder coupled to a second manifold exhaust port, and one runner of an inner cylinder coupled to the first manifold exhaust port and another runner of the inner cylinder coupled to the second manifold exhaust port.

Disclosed herein is an exhaust insulator structure for a multi-cylinder engine of a vehicle. The structure includes an exhaust manifold, an exhaust gas purifier, and a heat insulator. The engine is able to switch its mode of operation from an all-cylinder operation in which all of four cylinders thereof are activated to a cylinder-cutoff operation in which two of the four cylinders are deactivated to serve as idle cylinders and the other two cylinders are activated to serve as active cylinders, or vice versa. The exhaust manifold includes: idle-cylinder-connected branched exhaust piping communicating with the idle cylinders; and active-cylinder-connected branched exhaust piping communicating with the active cylinders. A portion of the heat insulator facing the active-cylinder-connected branched exhaust piping has an opening that lets air blowing against the vehicle traveling into the heat insulator.

Disclosed herein is an exhaust insulator structure for a multi-cylinder engine of a vehicle. The structure includes an exhaust manifold, an exhaust gas purifier, and a heat insulator. The engine is able to switch its mode of operation from an all-cylinder operation in which all of four cylinders thereof are activated to a cylinder-cutoff operation in which two of the four cylinders are deactivated to serve as idle cylinders and the other two cylinders are activated to serve as active cylinders, or vice versa. The exhaust manifold includes: idle-cylinder-connected branched exhaust piping communicating with the idle cylinders; and active-cylinder-connected branched exhaust piping communicating with the active cylinders. A portion of the heat insulator facing the active-cylinder-connected branched exhaust piping has an opening that lets air blowing against the vehicle traveling into the heat insulator.

A multi-cylinder engine exhaust structure disclosed herein includes: four branched exhaust pipes respectively communicating with four cylinders classified into two groups, each being comprised of two of the four cylinders with discontinuous exhaust strokes; two intermediate collecting pipes, each being formed by combining associated two of the four branched exhaust pipes respectively communicating with the two cylinders in an associated one of the two groups; a last collecting pipe formed by combining these intermediate collecting pipes; and an exhaust gas purifier coupled to an exhaust gas downstream end of the last collecting pipe. Two of the four branched exhaust pipes respectively communicating with two of the four cylinders to be activated as two active cylinders while the engine is performing a cylinder-cutoff operation are shorter than the two other branched exhaust pipes respectively communicating with the two other cylinders to be deactivated as two idle cylinders during the cylinder-cutoff operation.

A multi-cylinder engine exhaust structure disclosed herein includes: four branched exhaust pipes respectively communicating with four cylinders classified into two groups, each being comprised of two of the four cylinders with discontinuous exhaust strokes; two intermediate collecting pipes, each being formed by combining associated two of the four branched exhaust pipes respectively communicating with the two cylinders in an associated one of the two groups; a last collecting pipe formed by combining these intermediate collecting pipes; and an exhaust gas purifier coupled to an exhaust gas downstream end of the last collecting pipe. Two of the four branched exhaust pipes respectively communicating with two of the four cylinders to be activated as two active cylinders while the engine is performing a cylinder-cutoff operation are shorter than the two other branched exhaust pipes respectively communicating with the two other cylinders to be deactivated as two idle cylinders during the cylinder-cutoff operation.

The invention relates to a power unit, in particular for a hybrid vehicle, including a reciprocating-piston engine and at least one generator drivingly connected to the engine, wherein the engine has at least two pistons guided in at least two cylinders in a tandem arrangement, and two crankshafts, which are connected to the pistons by connection rods that run in opposite directions, and are mechanically coupled in the same phase. The engine includes a hub-hub connection with a first connection joining a first hub to a second hub such that an angular position between the first hub and the second hub is continuously adjustable on installation. The hub-hub connection also has a second connection in the form of a connection disk configured, dimensioned and arranged with support surfaces on each of which the first hub and the second hub rest. The connection disk has a matrix with hard material elements embedded therein, in particular diamond chips, which are arranged in the support surfaces for frictional engagement of the hubs.

The engine includes a cylinder head provided over a cylinder row, an intercooler provided on one end side of the cylinder head in a row direction of the cylinder row, an air supply manifold to introduce air from the intercooler to the cylinder head, and a cooling piping connected to the intercooler, where the cylinder head, air supply manifold, and cooling piping are arranged in a width direction intersecting the row direction of the cylinder row in stated order of the cylinder head, air supply manifold, and cooling piping, and in a cross section of the air supply manifold taken along a line intersecting the row direction, a length along the width direction is shorter than a length along a direction intersecting both the row direction and the width direction.

The engine includes a cylinder head provided over a cylinder row, an intercooler provided on one end side of the cylinder head in a row direction of the cylinder row, an air supply manifold to introduce air from the intercooler to the cylinder head, and a cooling piping connected to the intercooler, where the cylinder head, air supply manifold, and cooling piping are arranged in a width direction intersecting the row direction of the cylinder row in stated order of the cylinder head, air supply manifold, and cooling piping, and in a cross section of the air supply manifold taken along a line intersecting the row direction, a length along the width direction is shorter than a length along a direction intersecting both the row direction and the width direction.

Methods and systems are provided for a valve system for actuating two cylinder valves in an engine. In one example, the valve system may include a single pump and a solenoid valve capable of non-concurrently actuating the two cylinder valves coupled to separate cylinders.

Methods and systems are provided for a valve system for actuating two cylinder valves in an engine. In one example, the valve system may include a single pump and a solenoid valve capable of non-concurrently actuating the two cylinder valves coupled to separate cylinders.