Internal combustion engine and method of operating the same

A method for operating an internal combustion engine including:

• a cylinder having a cylinder bore defining a combustion chamber and a cylinder longitudinal axis;
• a crankcase connected to said cylinder;
• a crankshaft rotatably journalled in said crankcase;
• a piston disposed in said cylinder bore so as to move back and forth therein to drive said crankshaft in rotation and to delimit said combustion chamber;
• at least one transfer channel for connecting said crankcase to said combustion chamber in at least one position of said piston;
• said transfer channel having a predetermined length and a transfer window opening into said combustion chamber;
• said transfer channel being separated from the interior space of said cylinder bore over a portion of said length of said transfer channel;
• a supply channel having an inlet opening at said cylinder bore;
• and, said piston having at least one piston pocket;
• said piston pocket being configured to provide a connection between said supply channel and said transfer channel in at least one position of said piston;
• the method comprising the step of:
• during an upward stroke of said piston, causing all of said piston pocket to be first connected to said transfer window and then be connected to said inlet of said supply channel.

An internal combustion engine comprising:

• a cylinder having a cylinder bore defining a combustion chamber and a cylinder longitudinal axis;
• a crankcase connected to said cylinder;
• a crankshaft rotatably journalled in said crankcase;
• a piston disposed in said cylinder bore so as to move back and forth therein through a piston stroke (h) to drive said crankshaft in rotation and to delimit said combustion chamber;
• at least one transfer channel for connecting said crankcase to said combustion chamber in at least one position of said piston;
• said transfer channel having a predetermined length and a transfer window opening into said combustion chamber;
• said transfer channel being separated from the interior space of said cylinder bore over at least a portion of said length of said transfer channel;
• a supply channel having an inlet opening at said cylinder bore;
• said piston having at least one piston pocket;
• said piston pocket being configured to provide a connection for conducting a fluid between said supply channel and said transfer channel in at least one position of said piston;
• said transfer window having a lower edge facing toward said crankcase and said inlet opening having a lower edge facing toward said crankcase;
• said piston pocket having a first region passing over said transfer window during said stroke (h);
• said piston pocket having a first edge facing toward said combustion chamber and said first edge being a first control edge in said first region;
• said piston pocket having a second region passing over said inlet opening of said supply channel during said stroke (h);
• said piston pocket having a second edge facing toward said combustion chamber and said second edge being a second control edge in said second region;
• at bottom dead center of said piston, said first control edge being at a first distance (a, a′) to said lower edge of said transfer window measured parallel to said longitudinal axis;
• at said bottom dead center, said second control edge being at a second distance (b, b′) to said lower edge of said inlet opening of said supply channel measured parallel to said longitudinal axis;
• and
• said first distance (a, a′) being less than said second distance (b, b′) so as to cause all of said piston pocket to be first connected to said transfer window during said stroke (h) in an upward direction and thereafter to be connected to said inlet opening of said supply channel.