Reciprocating engine with extended minimum combustion chamber volume

A crankshaft system of piston engine, comprising:

• a main journal,
• a rod journal,
• a sun gear with a equivalent radius Rs and a total of Zs teeth,
• a planet gear with a equivalent radius Rp and a total of Zp teeth,
• a crankpin,
• a connecting rod,
• wherein the rod journal rotates around the main journal, the distance between the rod journal center and the main journal center is r, the planet gear rotates around the rod journal, and the rotation of the planet gear is outside of the sun gear and is constrained by the sun gear, the crankpin is mounted on the planet gear, the distance between the planet gear center and the crankpin center is m, the length of the connecting rod is L, a first end of the connecting rod is attached to the crankpin, a second end of the connecting is attached to a piston,
• wherein the main journal is fixed on a crankcase by a bearing and the main journal rotates in the bearing around its axle,
• wherein the sun gear is stationary with reference to the crankcase,
• wherein 0<m<r<L, m<Rp, k=Zs/Zp=Rs/Rp, k is integer 1, 2 or 3, Zs and Zp are integers,
• wherein when the piston is at its TDC position, all 4 restrictions are applied at same time:
• Restriction 1, crank angle=0;
• Restriction 2, the center of planet gear, the center of the sun gear and the center of the crankpin are aligned with the connecting rod;
• Restriction 3, the rod journal is at its uppermost position;
• Restriction 4, the center of the crankpin is at the lower side of the planet gear center,
• wherein the piston and a cylinder define a combustion chamber volume, the maximum combustion chamber volume defines a displacement of the piston, the combustion chamber volume when the piston is at its TDC position defines a minimum volume. The variation of the combustion chamber volume is within 0.2% of the displacement of the piston from 0° ATDC to Ax=14° ATDC and beyond.

A method of extending the minimum combustion chamber volume of a piston engine, comprising:

• a main journal,
• a rod journal,
• a constraining gear,
• a planet gear,
• a crankpin,
• a connecting rod,
• wherein the rod journal rotates around the main journal, the distance between the rod journal center and the main journal center is r, the planet gear rotates around the rod journal, the rotation of the planet gear is constrained by the constraining gear, the crankpin is mounted on the planet gear, the distance between the planet gear center and the crankpin center is m, the length of the connecting rod is L, a first end of the connecting rod is attached to the crankpin, a second end of the connecting is attached to a piston,
• wherein the main journal is fixed on a crankcase by a bearing and the main journal rotates in the bearing around its axle,
• wherein the constraining gear is stationary with reference to the crankcase,
• wherein the piston and a cylinder define a combustion chamber volume, the maximum combustion chamber volume defines a displacement, the combustion chamber volume when the piston is at its TDC position defines a minimum volume,
• wherein the number of teeth of the constraining gear is integer k times of the number of teeth of the planet gear, k=1, 2, 3, 4 or 5,
• wherein 0<m<r<L,
• wherein when the piston is at its TDC position, all 4 restrictions are applied at same time:
• Restriction 1, crank angle=0;
• Restriction 2, the center of planet gear, the center of the sun gear and the center of the crankpin are aligned with the connecting rod;
• Restriction 3, the rod journal is at its uppermost position;
• Restriction 4, the center of the crankpin is at the lower side of the planet gear center,
• wherein when the main journal rotates, the crankpin rotates around both the main journal and the planet gear center simultaneously but in different angular velocities, the trajectory of the crankpin is noncircular, the movement the first end of the connecting rod follows the trajectory of the crankpin. The variation of the combustion chamber volume is within 0.2% of the displacement of the piston from 0° ATDC to Ax=14° ATDC and beyond, this combustion chamber volume is referred to as an extended minimum combustion chamber volume from 0° ATDC to Ax=14° ATDC and beyond.