摘要:
An opposed-piston engine has a cylinder block with a plurality of cylinders arranged inline, with each cylinder including an intake port longitudinally separated from an exhaust port. The engine's air handling system includes open intake and exhaust chambers in the cylinder block. The open chamber constructions eliminate the need for multi-pipe manifolds and smooth the flow of charge air.
摘要:
An opposed-piston engine includes pistons, each piston having an annular cavity in the piston's sidewall and positioned between its crown and ring grooves to block transfer of heat from the crown to the piston body.
摘要:
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.
摘要:
An opposed-piston engine includes an inline cylinder block with an open exhaust chamber that contains all of the engine's exhaust ports. Exhaust outlets open from the exhaust chamber through opposing sides of the cylinder block. A turbocharger is positioned on each side of the cylinder block and has an inlet closely coupled with a respective exhaust outlet. The exhaust chamber is divided into separate collector sections, each collector section containing the exhaust ports of one or more cylinders, and each turbocharger has a first inlet closely coupled with a first collector section and a second inlet closely coupled with a second collector section. The engine has a cylinder firing sequence which alternates between the cylinders in the first and second collector sections.
摘要:
Methods are described for operating a two-stroke cycle, compression-ignition, opposed-piston engine using a self-igniting, low reactivity fuel which manages trapped temperature and trapped combustion residue within the combustion chambers of the engine, thereby ensuring fuel ignition timed to avoid misfires at low loads and pre-ignition (knocks) at high loads.
摘要:
A combustion chamber for an opposed-piston engine includes a squish zone defined between circumferential peripheral areas of opposing end surfaces of the pistons, a cavity defined by one or more bowls in the end surfaces, and at least one injection port that extends radially through the squish zone into the cavity. The cavity has a cross-sectional shape that imposes a tumbling motion on air flowing from the squish zone into the cavity. Opposing spray patterns of fuel are injected into the combustion chamber. Charge air is admitted into the bore from the intake port (224) as the pistons move from respective bottom dead center positions in the bore, a tumble component (343) is added to the motion of the air in the combustion chamber (300), and spray patterns (381) of fuel (248) are injected into the combustion chamber (300) in opposing radial directions of the cylinder.
摘要:
A mechanism for varying crankshaft timing on a belt/chain driven, dual crankshaft opposed-piston engine includes sprockets on corresponding ends of the two crankshafts, connected by a belt or chain which is tensioned by two or more tensioners. By changing the position of the tensioners the length of the two spans of the belt/chain are varied and thus the phase between the crankshafts is varied.
摘要:
A combustion chamber for an opposed-piston engine is defined between a pair of pistons disposed for opposing reciprocal movement in a cylinder. The combustion chamber is formed between crowns of the pistons and has a radius that decreases from the longitudinal axis of the cylinder. Each crown includes a periphery, a bow! within the periphery defining a concave surface with a first portion curving inwardly toward the interior of the piston and a second portion curving outwardly from the interior, and a convex surface within the periphery curving outwardly and meeting the second portion of the concave surface to form a ridge. Each ridge has a height thai decreases with the distance from a longitudinal axis.
摘要:
Exhaust temperature management strategies for an opposed-piston, two-stroke engine with EGR are based on control of a ratio of the mass of fresh air and external EGR delivered to a cylinder to the mass of the trapped charge (density of the delivered charge multiplied by the trapped volume at port closing).