The present invention discloses a control method of variable stroke engine for reforming high-octane fuel under the FCE mode, the ECU connected to the engine controls the amount of fuel injected from the flexible cylinder injector to the flexible cylinder and controls the switch state of inlet valve and exhaust valve of the flexible cylinder, so that the flexible cylinder can be switched between two-stroke mode and four-stroke mode according to the actual engine operating conditions; when the engine is at a small load and needs to promote combustion stability, the flexible cylinder injector injects a rich fuel with equivalence ratio greater than 1 into the flexible cylinder, the flexible cylinder is at two-stroke mode; when the engine is at a large load and needs sufficient power output, the flexible cylinder injector injects a conventional fuel into the flexible cylinder, said flexible cylinder is at four-stroke mode.

According to an aspect of the present invention, there is provided a combustion engine comprising a first exhaust gas channel and a separate second exhaust gas channel each connected to at least one cylinder, wherein the first exhaust gas channel is further connected to a turbocharger and the second exhaust gas channel is configured to bypass the turbocharger, and a throttling valve in the second exhaust gas channel configured to control an exhaust gas pressure in the cylinder.

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.

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.

According to an example aspect of the present invention, there is provided a combustion engine comprising a first exhaust gas channel and a separate second exhaust gas channel each connected to at least one cylinder, wherein the first exhaust gas channel is further connected to a turbocharger and the second exhaust gas channel is configured to bypass the turbocharger, and a throttling valve in the second exhaust gas channel configured to control an exhaust gas pressure in the cylinder.

Described herein is a system for variable actuation of an engine valve of an internal-combustion engine, where the system is able to actuate the engine valves, selectively, in a four-stroke operating mode and in a two-stroke operating mode, on the basis of the operating conditions of the engine.

Described herein is a system for variable actuation of an engine valve of an internal-combustion engine, where the system is able to actuate the engine valves, selectively, in a four-stroke operating mode and in a two-stroke operating mode, on the basis of the operating conditions of the engine.

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 center (UDC) towards lower dead center (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.

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.

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.