Removal and breakage of fuel piping during a vehicle front collision is prevented for an engine mounted longitudinally in an engine compartment. Embodiments include a side structure of the engine having an alternator in front of an intake manifold and fuel piping behind the intake manifold so as to extend in the vertical direction. The intake manifold includes a plurality of independent intake pipe portions each having one end portion connected to one side of the engine in a vehicle width direction, and a surge tank portion to which the other end portions of the independent intake pipe portions are connected. As seen from the rear side, a portion of the fuel piping closer to the surge tank portion is located closer to the one side of the engine in the vehicle width direction than the surge tank portion.

An intake manifold includes a surge tank, an inlet pipe, and intake pipes. The surge tank includes a curved portion and a bulging portion. The curved portion forms a curved outer wall of the surge tank and includes an inner surface that is continuous with inner surfaces of entrances of the intake pipes. The bulging portion bulges into the surge tank toward the curved portion and overlaps with an imaginary extension of an exit of the inlet pipe into the surge tank. The bulging portion includes a flow changing portion. The flow changing portion is configured to direct a flow of intake air toward a section that is more interior into the surge tank than the bulging portion in relation to the inlet pipe and located on part of the inner surface of the surge tank that is continuous with the inner surface of the curved portion.

The invention relates to a method of operating a four stroke internal combustion engine system (1), the engine system (1) comprising:—a four stroke internal combustion engine (2) provided with an intake duct (5),—a turbo compressor (6″) arranged to compress intake flow in the intake duct (5), and—a displacement machine (7) provided in the intake duct (5) downstream the turbo compressor (6″), wherein the displacement machine (7) is arranged to displace intake flow from an inlet to an outlet thereof. The method comprises the step of: operating the displacement machine (7) in a first mode where a pressure ratio (PR) given by a pressure at the outlet of the displacement machine (7) divided by a pressure at the inlet of the displacement machine (7) is substantially equal to 1. The invention also relates to a four stroke internal combustion engine system arranged to be operated by the above method.

A side part structure of an engine having cylinders lined up in a front-and-rear direction of a vehicle body, is provided. The structure includes auxiliary machinery disposed in a front part of one side wall part of the engine in a vehicle width direction, a fuel system component disposed in a rear part of the side wall part, an intercooler disposed between the auxiliary machinery and the fuel system component, and a first protector member disposed between the intercooler and the fuel system component. At least a front part of the first protector member is formed so as to be separated from the side wall part as it extends rearward. A front part of the intercooler is disposed rearward of the auxiliary machinery and the intercooler is disposed along the first protector member so as to be separated from the side wall part as it extends rearward.

The present invention refers to a spacer for use in an air intake system of an internal combustion engine for delimiting an intake duct between an intake manifold and a cylinder head of the engine, wherein the spacer is provided with at least one flow-through passage and at least one air-accumulation cavity which are fluid-communicatively connected and constitute the intake duct.

An air intake apparatus includes a plurality of funnel-shaped portions provided in a plurality of intake ports. The plurality of funnel-shaped portions respectively include open ends located at positions at which lengths of the plurality of intake ports are aligned with each other, the open ends being provided along a direction perpendicular to a direction in which respective centerlines of the plurality of intake ports extend.

The invention relates to a method of operating a four stroke internal combustion engine system (1), the engine system (1) comprising:—a four stroke internal combustion engine (2) provided with an intake duct (5),—a turbo compressor (6″) arranged to compress intake flow in the intake duct (5), and—a displacement machine (7) provided in the intake duct (5) downstream the turbo compressor (6″), wherein the displacement machine (7) is arranged to displace intake flow from an inlet to an outlet thereof. The method comprises the step of: operating the displacement machine (7) in a first mode where a pressure ratio (PR) given by a pressure at the outlet of the displacement machine (7) divided by a pressure at the inlet of the displacement machine (7) is substantially equal to 1. The invention also relates to a four stroke internal combustion engine system arranged to be operated by the above method.

An internal combustion engine includes a cylinder block including a cylinder, a cylinder head including an intake port, the intake port communicating with the cylinder, an intake manifold fixed to the cylinder head, the intake manifold being configured to supply intake air into the cylinder, and a dynamic vibration absorber configured to suppress vibration of the intake manifold. A direction that is orthogonal to both a central axis of the cylinder and a rotational axis of a crankshaft of the internal combustion engine is defined as a width direction. The dynamic vibration absorber is attached to the intake manifold on an opposite side of a center of gravity of the intake manifold from the cylinder head in the width direction.

A side part structure of an engine having cylinders lined up in a front-and-rear direction of a vehicle body, is provided. The structure includes auxiliary machinery disposed in a front part of one side wall part of the engine in a vehicle width direction, a fuel system component disposed in a rear part of the side wall part, an intercooler disposed between the auxiliary machinery and the fuel system component, and a first protector member disposed between the intercooler and the fuel system component. At least a front part of the first protector member is formed so as to be separated from the side wall part as it extends rearward. A front part of the intercooler is disposed rearward of the auxiliary machinery and the intercooler is disposed along the first protector member so as to be separated from the side wall part as it extends rearward.

An engine intake air duct 1 has an intake portion 10 that extends along a first center line A, and a main duct portion 20 that extends along a second center line B. The main duct portion 20 has a merging portion 50, a discharge opening 21, and an extending portion 40 that extends from the merging portion 50 towards an opposite end to the discharge opening 20. A reflecting wall 41 is provided at an end face of the extending portion 40. The intake portion 10 merges with the main duct portion 20 in such a way that the first center line A is directed towards a downstream end of the main duct portion 20.