Methods and systems are provided for a vehicle engine having a pre-chamber ignition system. In one example, a method may include adjusting one or more of an air injection amount and a fuel injection amount to a pre-chamber of an engine based on an air injection offset and a fuel injection offset learned while discontinuing fueling to cylinders of the engine and reducing air flow through the engine. In this way, air and fuel may be more accurately provided to the pre-chamber, thereby decreasing an occurrence of pre-chamber misfire.

Systems and methods for managing excessive intake flow path pressure and counter flow are implemented to support enhanced engine braking applications, such as 2-stroke or 1.5-stroke engine braking implementations where the intake flow path may be exposed to excessive transient pressures in the combustion chamber during activation or deactivation of an engine brake. Intake throttle, exhaust gas recirculation (EGR) valve, intake manifold blow-off valve, compressor bypass valve, exhaust throttle, turbocharger geometry or turbocharger waste gate may be controlled to effectuate counter flow management separately or in combination. Excessive transient conditions may also be prevented or managed by sequential valve motion in which brake motion activation occurs first and then exhaust valve main event deactivation occurs second. Delay between brake activation and main event deactivation may be facilitated using mechanical and/or hydraulic implements as well as electronically.

One embodiment is a system comprising an engine including a dedicated EGR cylinder configured to provide EGR to the engine via an EGR loop, a non-dedicated cylinder, a plurality of injectors, an ignition system including a plurality of spark plugs, an intake throttle, and an electronic control system. The electronic control system is configured to control combustion during transient operation of the engine by determining one or more combustion control parameters compensating for variation of one or more of inert matter, unburned air and unburned fuel in EGR output by the dedicated EGR cylinder during transient operation of the engine, and an effect of the EGR loop on inert matter, unburned air and unburned fuel provided to the plurality of cylinders, and controlling operation of at least one of the throttle, the ignition system and the plurality of injectors in response to at least one of the one or more combustion control parameters.

The solution of the invention is an internal combustion engine with oxygen concentrating equipment (80) wherein the air compressed in the compression stroke is not yet used for combustion but taken out of the cylinder space (15) and used for operating the oxygen concentrating equipment (80). The essence of the invention is that the cylinder space (15) and one or more cells of the oxygen concentrating equipment (80) are temporarily connected during each compression stroke of the engine. The air taken in the cylinder space (15) during the intake stroke and pushed out by the piston (5) during the compression stroke charges one or more cells (41 A-41Z, 51 A-51Z) of the oxygen concentrating equipment (80) and after separating most of the nitrogen in the cells (41 A-41Z, 51A-51Z), the oxygen rich air is injected into the cylinder space (15) through a compressor (33) at the beginning of the expansion stroke by an injector (11). The fuel is also introduced into the cylinder space (15) at the beginning of the expansion stroke by an injector. The ignition may be spark ignition, self-ignition (heat ignition) or their load dependent, speed dependent or power requirement dependent dynamic combination. The invention further relates to the method, the computer program product and the computer-readable medium operating the internal combustion engine with oxygen concentrating equipment.

An engine system includes main exhaust ports fluidly communicating with each combustion chamber. An exhaust variable valve lift apparatus controls an operation of a main exhaust valve which closes or opens each main exhaust port. A main exhaust manifold is connected with the main exhaust ports. Scavenge exhaust ports fluidly communicate with each combustion chamber. A variable scavenge apparatus controls an operation of a scavenge valve which closes and opens each scavenge exhaust port. A scavenge manifold is connected with the scavenge exhaust ports. A controller is configured to control operations of the exhaust variable valve lift apparatus and the variable scavenge apparatus according to a vehicle operation state.

Disclosed is a combustion engine and method for engine braking therein including an intake air channel having a first pressure, a first inlet valve between the intake air channel and the cylinder volume, an exhaust air channel having a second pressure, a first outlet valve between the cylinder volume and the exhaust air channel, and a storage reservoir having a third pressure higher than the first and second pressures, the storage reservoir being arranged in controllable fluid communication with the cylinder volume. The method takes place during two-stroke cycle and includes: displacing the piston from upper dead centre (UDC) towards lower dead centre (LDC), keeping the first inlet valve open during at least part of the travel from UDC to LDC, displacing the piston from LDC towards UDC, and keeping the fluid communication between the storage reservoir and cylinder volume open during at least a part of such travel.

An engine valve actuation mechanism for producing a variable engine valve event includes a cam, a rocker arm, a rocker arm shaft, an eccentric rocker arm bushing, and a bushing actuation device. The eccentric rocker arm bushing is disposed in an axial hole in the rocker arm, the rocker arm shaft being disposed in the eccentric rocker arm bushing with the rocker arm shaft and the eccentric rocker arm bushing having offset axial centerlines. One end of the rocker arm and the cam is connected to form a kinematic pair and the other end of the rocker arm is located above the engine valve with a gap between the cam and the engine valve. The bushing actuation device is placed in the rocker arm and drives the eccentric rocker arm bushing to rotate, and the rotation of the eccentric rocker arm bushing changes the gap to generate the variable engine valve event.

A two-stroke, opposed-piston engine includes a cylinder with an inlet piston controlled inlet port and an exhaust piston controlled exhaust port, the cylinder defining a combustion chamber with the inlet piston and the exhaust piston, a charge air channel in flow communication with the inlet port, a conduit extending directly from the combustion chamber to the charge air channel, and a valve arranged to selectively open and close flow communication through the conduit.

A residual gas ignitor for use in igniting a fuel-air mixture within a main combustion chamber of an engine. The residual gas ignitor includes at least one inlet/outlet port, a residual gas ignitor chamber for receiving a combustion gas from the main combustion chamber, an ignitor valve for opening and closing the at least one inlet/outlet port, an actuator for actuating the ignitor valve to open and close the at least one inlet/outlet port, a valve guide for keeping the ignitor valve in a correct orientation within the residual gas ignitor, a preload spring for being in compression when the actuator disposes the ignitor valve into the closed position, and a heating element for maintaining or increasing a temperature of the combustion gas while the combustion gas is in the residual gas ignitor chamber. The residual gas ignitor may be used in engines for initiating combustion of fuel-air mixtures.

Methods and systems are provided for transferring hot, compressed gases from one cylinder to another cylinder while fuel injection in both cylinders is deactivated. In one example, a method may include during a fuel shut-off event, opening a first pre-chamber injector of the first cylinder undergoing late compression or early expansion and opening a second pre-chamber injector of the second cylinder undergoing a late expansion and/or exhaust stroke or undergoing an intake stroke to allow a hot, compressed gas from the first cylinder to transfer to the second cylinder through the first and second pre-chamber injectors.