Reciprocating piston mechanism and a method of increasing internal EGR in an internal combustion engine

A reciprocating piston mechanism comprising

• a crankcase;
• a crankshaft having at least a crankpin, said crankshaft being supported by the crankcase and rotatable with respect thereto about a crankshaft axis;
• at least a connecting rod including a big end and a small end;
• a piston being rotatably connected to the small end;
• a crank member being rotatably mounted on the crankpin, and comprising at least a bearing portion which is eccentrically disposed with respect to the crankpin, and having an outer circumferential wall which bears the big end of the connecting rod such that the connecting rod is rotatably mounted on the bearing portion of the crank member via the big end;
• wherein the crank member is provided with a crank member gear which meshes with a first auxiliary gear being an external gear, wherein the first auxiliary gear is fixed to a second auxiliary gear via a common auxiliary shaft, which auxiliary shaft is mounted to the crankshaft, wherein an auxiliary shaft axis is spaced apart from the crankshaft axis and is configured to rotate about the crankshaft axis, which second auxiliary gear meshes with a central gear having a center line which coincides with the crankshaft axis;
• and wherein the crank member gear is an internal gear;
• and
• wherein the crankshaft comprises at least a second crankpin which is angularly spaced with respect to the crankpin about the crankshaft axis, and at least a second crank member rotatably mounted on the second crank pin, wherein the second crank member is provided with a second crank member gear being an internal gear which meshes with a third auxiliary gear being an external gear, wherein the third auxiliary gear is fixed to a fourth auxiliary gear via a common second auxiliary shaft, which second auxiliary shaft is mounted to the crankshaft wherein a second auxiliary shaft axis is spaced apart from the crankshaft axis and is configured to rotate about the crankshaft axis, which fourth auxiliary gear meshes with the central gear.

A reciprocating piston mechanism comprising

• a crankcase;
• a crankshaft having at least a crankpin, said crankshaft being supported by the crankcase and rotatable with respect thereto about a crankshaft axis;
• at least a connecting rod including a big end and a small end;
• a piston being rotatably connected to the small end;
• a crank member being rotatably mounted on the crankpin, and comprising at least a bearing portion which is eccentrically disposed with respect to the crankpin, and having an outer circumferential wall which bears the big end of the connecting rod such that the connecting rod is rotatably mounted on the bearing portion of the crank member via the big end;
• wherein the crank member is provided with a crank member gear, being an external gear, which meshes with a first auxiliary gear being an external gear, wherein the first auxiliary gear is fixed to a second auxiliary gear, being an external gear, via a common auxiliary shaft, which auxiliary shaft is mounted to the crankshaft, wherein an auxiliary shaft axis is spaced apart from the crankshaft axis and is configured to rotate about the crankshaft axis, which second auxiliary gear meshes with an intermediate auxiliary gear, being an external gear, which intermediate auxiliary gear also meshes with a central gear, being an internal gear, having a center line which coincides with the crankshaft axis.

A reciprocating piston mechanism comprising a crankcase;

• a crankshaft having at least a crankpin, said crankshaft being supported by the crankcase and rotatable with respect thereto about a crankshaft axis;
• at least a connecting rod including a big end and a small end;
• a piston being rotatably connected to the small end;
• a crank member being rotatably mounted on the crankpin, and comprising at least a bearing portion which is eccentrically disposed with respect to the crankpin, and having an outer circumferential wall which bears the big end of the connecting rod such that the connecting rod is rotatably mounted on the bearing portion of the crank member via the big end;
• wherein the crank member is drivably connected to an auxiliary shaft via a first transmission wherein the auxiliary shaft is mounted to the crankshaft wherein an auxiliary shaft axis is spaced apart from the crankshaft axis and is configured to rotate about the crankshaft axis, wherein the auxiliary shaft is drivably connected to a central ring via a second transmission, wherein the central ring has a center line which coincides with the crankshaft axis;
• wherein the first and second transmission are configured such that the crank member rotates at a rotation frequency with respect to the crankcase which is substantially half of that of the crankshaft when the central ring has a fixed position with respect to the crankcase;
• wherein the first transmission comprises a crank member gear being an external gear and mounted to the crank member, and a first auxiliary gear being an external gear and fixed to the auxiliary shaft, wherein the crank member gear and the first auxiliary gear mesh with each other;
• and
• wherein the second transmission comprises a second auxiliary gear being an external gear and mounted to the auxiliary shaft, which second auxiliary gear meshes with an intermediate auxiliary gear, being an external gear, which intermediate auxiliary gear also meshes with an internal gear of the central ring.