A system and method for a variable displacement internal combustion engine using different types of pneumatic cylinder springs on skipped working cycles to control engine and aftertreatment system temperatures are described. The system and method may be used to rapidly heat up the aftertreatment system(s) and/or an engine block of the engine following a cold start by using one or more different types of pneumatic cylinder springs during skipped firing opportunities. By rapidly heating the aftertreatment system(s) and/or engine block, noxious emissions such as hydrocarbons, carbon monoxide, NO.sub.x and/or particulates, following cold starts are significantly reduced.

A system and method for a variable displacement internal combustion engine using different types of pneumatic cylinder springs on skipped working cycles to control engine and aftertreatment system temperatures are described. The system and method may be used to rapidly heat up the aftertreatment system(s) and/or an engine block of the engine following a cold start by using one or more different types of pneumatic cylinder springs during skipped firing opportunities. By rapidly heating the aftertreatment system(s) and/or engine block, noxious emissions such as hydrocarbons, carbon monoxide, NO.sub.x and/or particulates, following cold starts are significantly reduced.

Disclosed is an internal combustion engine including: an actuator for axial displacement of at least one gas exchange valve of the internal combustion engine, wherein the actuator includes: an actuator piston disc, a cylinder volume adapted for the actuator piston disc, wherein the actuator piston disc is movably arranged in an axial direction between a rest position and an active position, wherein the position sensor arrangement is configured for determining the position of the at least one gas exchange valve, the at least one gas exchange valve being displaced by the movement of the actuator piston disc, and a local control unit associated with the actuator, wherein the local control unit is operatively connected to the at least one controllable inlet valve and the controllable outlet valve of the actuator and operatively connected to the position sensor arrangement.

Disclosed is an internal combustion engine including: an actuator for axial displacement of at least one gas exchange valve of the internal combustion engine, wherein the actuator includes: an actuator piston disc, a cylinder volume adapted for the actuator piston disc, wherein the actuator piston disc is movably arranged in an axial direction between a rest position and an active position, wherein the position sensor arrangement is configured for determining the position of the at least one gas exchange valve, the at least one gas exchange valve being displaced by the movement of the actuator piston disc, and a local control unit associated with the actuator, wherein the local control unit is operatively connected to the at least one controllable inlet valve and the controllable outlet valve of the actuator and operatively connected to the position sensor arrangement.

The invention relates to a cylinder valve assembly (19) comprising a pneumatic valve spring arrangement (25) including a first (29) and a second (31) valve spring member defining a valve spring cavity (33), and a valve spring venting arrangement (27) comprising a first venting cavity portion (37) in fluid flow connection with the valve spring cavity (33); a second venting cavity portion (39); a movable sealing member (41) arranged to allow a pressure difference between the first venting cavity portion (37) and the second venting cavity portion (39); a feedback channel fluid flow connecting the first venting cavity portion (37) and the second venting cavity portion (39); and a venting channel (53). The sealing member (41) is configured to be movable between a first sealing member position where the sealing member (41) prevents fluid flow from the first venting cavity portion (37) through the venting channel (53); and a second sealing member position where the sealing member (41) allows fluid flow from the first venting cavity portion (37) through the venting channel (53). The valve spring venting arrangement (27) further comprises an elastic member (55) urging the sealing member (41) towards the first sealing member position.

The invention relates to a cylinder valve assembly (19) comprising a pneumatic valve spring arrangement (25) including a first (29) and a second (31) valve spring member defining a valve spring cavity (33), and a valve spring venting arrangement (27) comprising a first venting cavity portion (37) in fluid flow connection with the valve spring cavity (33); a second venting cavity portion (39); a movable sealing member (41) arranged to allow a pressure difference between the first venting cavity portion (37) and the second venting cavity portion (39); a feedback channel fluid flow connecting the first venting cavity portion (37) and the second venting cavity portion (39); and a venting channel (53). The sealing member (41) is configured to be movable between a first sealing member position where the sealing member (41) prevents fluid flow from the first venting cavity portion (37) through the venting channel (53); and a second sealing member position where the sealing member (41) allows fluid flow from the first venting cavity portion (37) through the venting channel (53). The valve spring venting arrangement (27) further comprises an elastic member (55) urging the sealing member (41) towards the first sealing member position.

Embodiments disclosed herein relate to internal combustion engines, combustion systems that include such internal combustion engines, and controls for controlling operation of the combustion engine. The internal combustion engine may include one or more mechanisms for injecting fuel, air, fuel-air mixture, or combinations thereof directly into one or more cylinders, and controls may operate or direct operation of such mechanisms.

The invention pertains to gas exchange in internal combustion engines using low to zero-emission fuels. The combustion engine has the ability to regulate the quantity of air/fuel mixture in the cylinder using one or more exhaust valve(s) (2) that can have adjustable opening times in order to control the gas exchange in the cylinder so that exhaust and alternatively also air can be expelled into the exhaust system. By reducing the quantity of air and thus the quantity of fuel for each cycle, that combined with reduced compression pressure means that engines can operate with a higher expansion ratio by leaving the exhaust valve(s) (2) open through a part of the compression stroke to reduce the amount of air to the combustion and reduce compression and then pressure rise before combustion. Air volume and gas exchange are regulated by compressor(s) (5) as well as opening and closing of exhaust valve(s) (2) with the exhaust valve control (4); alternatively, also intake valves for 4-stroke engines.

The invention pertains to gas exchange in internal combustion engines using low to zero-emission fuels. The combustion engine has the ability to regulate the quantity of air/fuel mixture in the cylinder using one or more exhaust valve(s) (2) that can have adjustable opening times in order to control the gas exchange in the cylinder so that exhaust and alternatively also air can be expelled into the exhaust system. By reducing the quantity of air and thus the quantity of fuel for each cycle, that combined with reduced compression pressure means that engines can operate with a higher expansion ratio by leaving the exhaust valve(s) (2) open through a part of the compression stroke to reduce the amount of air to the combustion and reduce compression and then pressure rise before combustion. Air volume and gas exchange are regulated by compressor(s) (5) as well as opening and closing of exhaust valve(s) (2) with the exhaust valve control (4); alternatively, also intake valves for 4-stroke engines.

A system and method for controlling an internal combustion engine involving (1) cylinder trapping strategies where one of several pneumatic spring types are dynamically selected for cylinders based at least partially on a predicted number of upcoming skips for each of the cylinders respectively and/or (2) staggering various valvetrain dependent operational engine strategies as operating conditions permit as the internal combustion engine warms up following a cold start.