An opposed piston engine includes a cylinder having a cylinder wall, and a pair of opposed pistons, Each face of each piston of the pair of opposed pistons has a top plane and a recess formed therein, each recess comprising a first surface defining part of a cone, the cone defined by the first surface of at least one of the recesses having a longitudinal axis that defines an angle equal to at least one half of a cone angle of the cone with the top plane.

A fuel injection device including a valve body having an injection hole-formed part having a plurality of injection holes on the leading end side of the valve body. An injection hole comprises a crossing angle, θ1, between a central axis of the injection hole-formed part and an injection hole axis, and another injection hole comprises a crossing angle, θ2, between the central axis and another injection hole axis. θ2 is larger than θ1. The injection holes are formed such that a distance between the central axis and an inlet surface center of the injection hole is longer than a distance between the central axis and another inlet surface center of the another injection hole. A straight line beyond an outlet surface in the injection hole axis does not intersect with another straight line beyond another outlet surface in the another injection hole axis.

An engine includes a combustion chamber including a cylinder wall defining a cylinder, a fuel injector disposed in a first opening in the cylinder wall and a piston head disposed in the cylinder. A piston bowl at least partially defined by a wall having a generally spiral shape is provided in a top of the piston head.

A fuel injection device including a valve body having an injection hole-formed part having a plurality of injection holes on the leading end side of the valve body. An injection hole comprises a crossing angle, 1, between a central axis of the injection hole-formed part and an injection hole axis, and another injection hole comprises a crossing angle, 2, between the central axis and another injection hole axis. 2 is larger than 1. The injection holes are formed such that a distance between the central axis and an inlet surface center of the injection hole is longer than a distance between the central axis and another inlet surface center of the another injection hole. A straight line beyond an outlet surface in the injection hole axis does not intersect with another straight line beyond another outlet surface in the another injection hole axis.

A combustion chamber for an opposed-piston engine has a rotationally skewed shape in a longitudinal section that is orthogonal to a chamber centerline, between diametrically-opposed openings of the combustion chamber through which fuel is injected. The rotationally skewed shape interacts with swirl to generate a tumble bulk charge air motion structure that increases turbulence.

A piston may include an outer peripheral surface and a crown. The outer peripheral surface may include first and second openings spaced about and extending through the outer peripheral surface. The crown may include a recess at least partially defined by a first lobe in fluid communication with the first opening and a second lobe in fluid communication with the second opening. Each of the first and second lobes may be recessed relative to an adjacent portion of the recess of the crown.

An opposed piston engine may include a first housing, first and second pistons, and first, second, and third fuel injector nozzles. The first housing may define a first passage extending along a first longitudinal axis. The first and second pistons may be slidably disposed within the first passage. The first, second, and third fuel injector nozzles may be in fluid communication with the first passage. At least one of the first, second, and third fuel injector nozzles may be angularly offset from another one of the first, second, and third fuel injector nozzles by an oblique angle about the first longitudinal axis.

A combustion chamber for an opposed-piston engine has an elongated asymmetrical shape in longitudinal section that runs along a chamber centerline, between diametrically-opposed openings of the combustion chamber through which fuel is injected. The asymmetry apportions combustion chamber volume to provide additional clearance on a side of the chamber centerline toward which swirl is directed, thereby giving a fuel plume space to swing without hindrance in response to swirl.

An opposed piston engine includes a cylinder having a cylinder wall, and a pair of opposed pistons, Each face of each piston of the pair of opposed pistons has a top plane and a recess formed therein, each recess comprising a first surface defining part of a cone, the cone defined by the first surface of at least one of the recesses having a longitudinal axis that defines an angle equal to at least one half of a cone angle of the cone with the top plane.

A combustion chamber for an opposed-piston engine has a rotationally skewed shape in a longitudinal section that is orthogonal to a chamber centerline, between diametrically-opposed openings of the combustion chamber through which fuel is injected. The rotationally skewed shape interacts with swirl to generate a tumble bulk charge air motion structure that increases turbulence.