Marine engine intake manifolds having noise attenuation

An intake manifold for a marine engine having a throttle for controlling flow of intake air to the marine engine, the intake manifold comprising:

• a plenum for receiving the intake air from the throttle,
• a plurality of intake runners which extends from upstream ends receiving the intake air from the plenum to downstream ends for discharging the intake air to the marine engine,
• a quarter wave resonator having an elongated cavity extending from an open end coupled to the plenum to a closed end, the elongated cavity being tuned to attenuate sound emanating from the marine engine via the plurality of intake runners, wherein the quarter wave resonator comprises an elongated body extending alongside the plurality of intake runners and an elbow portion which couples the elongated body to the plenum, and
• a sensor coupled to the elbow portion and exposed to the plenum via the open end of the elongated cavity, the sensor being configured to sense temperature and pressure of the intake manifold.

A marine engine comprising:

• an engine block having a plurality of cylinders for combustion, wherein the engine block extends in a length direction, in a width direction which is perpendicular to the length direction, and in a height direction that is perpendicular to the length direction and perpendicular to the width direction,
• a throttle for controlling flow of intake air to the engine block,
• an intake manifold, the intake manifold comprising a plenum for receiving the intake air from the throttle and a plurality of intake runners which are aligned in a stack relative to the height direction and longitudinally extends from upstream ends receiving the intake air from the plenum to downstream ends discharging the intake air to the plurality of cylinders, and
• a quarter wave resonator extending from an open end coupled to the plenum to a closed end, the quarter wave resonator being located on one side of the stack relative to height direction and having an elongated cavity which is tuned to attenuate sound emanating from the marine engine via the plurality of intake runners.

A marine engine comprising:

• an engine block having a plurality of cylinders for combustion, wherein the engine block extends in a length direction, in a width direction which is perpendicular to the length direction, and in a height direction that is perpendicular to the length direction and perpendicular to the width direction,
• a throttle for controlling flow of intake air to the engine block,
• an intake manifold, the intake manifold comprising a plenum for receiving the intake air from the throttle and a plurality of intake runners which longitudinally extends from upstream ends receiving the intake air from the plenum to downstream ends discharging the intake air to the plurality of cylinders, and
• a quarter wave resonator extending from an open end coupled to the plenum to a closed end, the quarter wave resonator longitudinally extending alongside the plurality of intake runners and having an elongated cavity which is tuned to attenuate sound emanating from the marine engine via the plurality of intake runners, wherein the upstream ends of the plurality of intake runners has a stepped formation relative to the plenum.

A marine engine comprising:

• an engine block having a plurality of cylinders for combustion, wherein the engine block extends in a length direction, in a width direction which is perpendicular to the length direction, and in a height direction that is perpendicular to the length direction and perpendicular to the width direction,
• a throttle for controlling flow of intake air to the engine block,
• an intake manifold, the intake manifold comprising a plenum for receiving the intake air from the throttle and a plurality of intake runners which longitudinally extends from upstream ends receiving the intake air from the plenum to downstream ends discharging the intake air to the plurality of cylinders,
• a quarter wave resonator extending from an open end coupled to the plenum to a closed end, the quarter wave resonator longitudinally extending alongside the plurality of intake runners and having an elongated cavity which is tuned to attenuate sound emanating from the marine engine via the plurality of intake runners, wherein the quarter wave resonator comprises an elongated body extending alongside the plurality of intake runners and an elbow portion which couples the elongated body to the plenum, and further comprising a sensor coupled to the elbow portion and exposed to the plenum via the open end of the elongated cavity, the sensor being configured to sense temperature and pressure of the intake manifold.

A marine engine comprising:

• an engine block having a plurality of cylinders for combustion, wherein the engine block extends in a length direction, in a width direction which is perpendicular to the length direction, and in a height direction that is perpendicular to the length direction and perpendicular to the width direction,
• a throttle for controlling flow of intake air to the engine block,
• an intake manifold, the intake manifold comprising a plenum for receiving the intake air from the throttle and a plurality of intake runners which longitudinally extends from upstream ends receiving the intake air from the plenum to downstream ends discharging the intake air to the plurality of cylinders, and
• a quarter wave resonator extending from an open end coupled to the plenum to a closed end, the quarter wave resonator longitudinally extending alongside the plurality of intake runners and having an elongated cavity which is tuned to attenuate sound emanating from the marine engine via the plurality of intake runners, wherein the intake manifold comprises a monolithic inner manifold half and a monolithic outer manifold half which are mated together to define the plurality of intake runners, the plenum, and the quarter wave resonator.