An engine includes a combustion chamber, a cylinder head, an intake valve, a partition wall plate, and a tumble valve. The cylinder head includes an intake port that communicates with the combustion chamber. The intake valve includes a head configured to open and close an open end of the intake port. The partition wall plate partitions the intake port into first and second passages. The tumble valve is configured to open and close either one of the first passage and the second passage. A cross sectional shape of the partition wall plate is defined on a basis of a shape of a gap that is surrounded by a contour of the head and a contour of the open end, as viewed in a reference direction. The reference direction is a direction from a reference point in the intake port to a gap between the open end and the head.

An air intake set for a motor vehicle engine, including an air intake hose, a flow meter and a device for directing an air flow positioned upstream of the flow meter with respect to the direction of circulation of the air flow in the hose. The device for directing an air flow is adapted to guide the air flow towards the flow meter and has a variable permeability so as to set the velocity of the air flow.

An explosion relief valve for a crankcase of an engine includes a carrier plate, a cap, and an annular flame arrestor. The carrier plate includes a valve plate that has a sinuous shape for redirecting flame back into the engine The flame arrestor includes a plurality of layers of smooth metal sheets, with each layer having a pattern of apertures that is different in size and spacing than the pattern of apertures of its adjacent layer. The apertures of each layer are partially, and only partially, aligned with the perforations of its adjacent layers. The layers are laid flush against each other to minimize or eliminate air space between the layers, leaving only the air channels existing between the apertures of the metal sheet layers as passageways for exhaust gases to be released from the valve.

In an engine compartment, a separation wall is provided between an intake pipe, which runs around to a rear side of the engine from a lateral side of the engine, and the engine. On an outer side of this separation wall, a travel wind guide having a vertical wall portion that opposes the separation wall with the intake pipe being therebetween is provided. The travel wind guide guides vehicle travel wind that is introduced into the engine compartment in a manner to cause the vehicle travel wind to flow along the intake pipe on the outer side of the separation wall.

A rectification structural body includes an inlet port into which air from an air cleaner flows, an outlet port from which air flows out toward an airflow sensor, and a chamber provided between the inlet port and the outlet port. The inlet port and the outlet port are provided in such directions and at such positions that an air flow is bent in the chamber. The chamber includes two cases of a first case and a second case, the chamber being divided into the two cases.

The subject matter of this specification can be embodied in, among other things, a gas mixer that includes a convergent-divergent nozzle comprising a convergent portion and a divergent portion and defining a first gas flow path, an air housing comprising an air inlet configured to supply air to the first gas flow path upstream of the convergent-divergent nozzle, a gas housing defining a second gas flow path and including a first gas inlet configured to receive a secondary gas and allow the secondary gas into a second gas flow path, and a gas nozzle positioned parallel to and centrally within the first gas flow path in a convergent portion of the convergent-divergent nozzle, the gas nozzle configured to supply the secondary gas to the first gas flow path upstream of the divergent portion.

A vehicle has an upper hood duct with an air intake adjoining a hood air intake structure. A lower hood duct is connected to the upper hood duct. An on-engine air cleaner is connected to the lower hood duct. An auxiliary air inlet is arranged in the lower hood duct. The auxiliary air inlet may have an auxiliary air inlet door connected to an auxiliary air inlet door adapter by way of a hinge. The auxiliary air inlet door adapter may be connected to an auxiliary air inlet door adapter base attached to the lower hood duct. An electric or pneumatic actuator may be connected to the auxiliary air inlet door by way of an actuator door connection, and to the auxiliary air inlet door adapter by way of an actuator adapter connection.

A pre-cleaner for an internal combustion engine is arranged in an intake passage of the internal combustion engine at an upstream side of a filter of an air cleaner. The pre-cleaner includes a casing that includes a cylindrical side wall and swirl generation vanes that swirl intake air about an axis of the casing. The side wall has a portion located next to an upstream side of the swirl generation vanes that is formed from an air-permeable fibrous molded body.

A mixer for a gas flow system, such as an exhaust gas recirculation system, is provided. In one example, a gas flow system for an engine includes a first passage through which a first gas is configured to flow along a first axis; a second passage through which a second gas is configured to flow along a second axis, the first passage fluidly coupled to the second passage at an outlet of the first passage; and a mixer integrated with the first passage at the outlet and extending into the second passage, the mixer including an extension extending radially around the first axis and a main body extending into the second passage along the first axis.

An air cleaner for vehicles includes: a case having an inlet, through which outside air is introduced, and an outlet, through which filtered air is discharged; and a filter installed in an inner space of the case, configured to filter the outside air introduced through the inlet, and including a filtration member, wherein the filtration member is formed in an “∩” shape open downwards and is configured to allow the outside air to pass therethrough in a downward direction and in a lateral direction.