Opposed piston engine with piston compliance
An engine having a cylinder with a bore opposed pistons disposed for reciprocation in the bore includes compliant members that allow for angular adjustment of piston structure with respect to the cylinder in response to an imbalance in forces coupled to the pistons by connecting rods.
1. An opposed piston engine including a crankshaft, a cylinder, a pair of opposed pistons disposed for reciprocal movement in the cylinder, and connecting rods coupled to the crankshaft, each piston including an elastically deformable member between the piston and a respective connecting rod; in which,
each piston includes a cylindrical body with a skirt, an open end, and a closed end defining a crown, a piston rod with first and second ends, the first end attached to a back of the crown and the second end extending through the open end, and an associated wristpin attaching the second end to a respective pair of connecting rods, the elastically deformable member including a resiliently deformable boot retaining the first end; and,
the piston rod includes a bore and the piston includes a longitudinal axis and an array of passages symmetrically disposed about the longitudinal axis and abutting the back surface of the crown, each of said passages being in fluid communication with the bore and opening to an inside surface of the skirt.
2. The engine of claim 1 , in which the resiliently deformable boot comprises a fluoro-elastomeric material.
3. The engine of claim 2 , in which the piston rod is a flexible rod.
4. The engine of claim 1 , the piston rod further including a disc-shaped section on the first end, the disc-shaped section being retained in the resiliently deformable boot and secured to the back of the crown, with a portion of the resiliently deformable boot located between the disc-shaped section and the back of the crown.
5. The engine of claim 4 , in which the piston rod is aligned with the longitudinal axis and the disc-shaped section is connected to the array of passages, with a portion of the resiliently deformable boot located between the disc-shaped section and the array of passages.
6. An assembly for a diesel engine, including:
a cylinder;
a pair of opposed pistons disposed for reciprocal movement in the cylinder;
and, each piston including a crown, a piston rod, and an elastically deformable member retaining the piston rod at the back surface of the crown;
in which the piston rod includes a bore and the piston includes a longitudinal axis and an array of passages symmetrically disposed about the longitudinal axis and abutting the back surface of the crown, each of said passages being in fluid communication with the bore and opening to an inside surface of the skirt.
7. The assembly of claim 6 , the elastically deformable member for the piston including a resiliently deformable boot between the first end and the back surface of the crown.
8. The assembly of claim 7 , in which the resiliently deformable boot comprises a fluoro-elastomeric material.
9. The assembly of claim 7 , in which the piston rod is a flexible rod.
10. The assembly of claim 7 , in which the piston rod further including a disc-shaped section on the first end, the disc-shaped section being retained in the resiliently deformable boot and secured to the back of the crown, with at least a portion of the resiliently deformable boot located between the disc-shaped section and the back of the crown.
11. The engine of claim 10 , in which the piston rod is aligned with the longitudinal axis and the disc-shaped section is connected to the array of passages, with a portion of the resiliently deformable boot located between the disc-shaped section and the array of passages.
12. A method of operating an internal combustion engine including a pair of crankshafts, a cylinder and a pair of opposed pistons disposed for reciprocal movement in the cylinder, in which each piston includes a crown with a back surface internal to the piston, a piston rod with a bore and an end attached to the back surface of the crown, a skirt with an open end, and an elastically deformable element located between the end of the piston rod and the back surface of the crown, the engine further including structures connecting each of the piston rods to the crankshafts the method including:
retaining the attached ends of the pistons in respective elastically deformable elements;
elastically deforming the element of one of the pistons in response to an imbalance in forces coupled to a the piston rod of the piston from the crankshafts;
providing a first stream of a liquid coolant directed through the bore of the piston rod and the element toward the back surface; and,
fanning the first stream into a plurality of symmetrically-distributed second streams that flow on the back surface, along the piston skirt, and out of the open end of the piston.
13. The method of claim 12 , further including asymmetrically cooling the cylinder.
14. The method of claim 12 , in which the element includes a boot and elastically deforming the element includes deforming the boot.
15. An opposed piston engine including a pair of crankshafts, a cylinder, a pair of opposed pistons disposed for reciprocal movement in the cylinder, and structures connecting each of the pistons to the crankshafts; wherein,
at least one piston includes a cylindrical body with a skirt, an open end, and a closed end defining a crown;
the structure connecting the at least one piston to the crankshafts includes a piston rod with a bore and a first end attached to a back of the crown and a resiliently deformable boot between the first end and the back of the crown; and,
the back of the crown includes a plurality of symmetrically-arranged passages in communication with the bore and extending radially to the piston skirt.
16. The engine of claim 15 , in which the structure connecting the at least one piston to the crankshaft further includes a second end of the piston rod extending through the open end, a wristpin on the second end, and one or more connecting rods coupled to the wristpin and the crankshaft.
17. The engine of claim 16 , in which the resiliently deformable boot comprises a fluoro-elastomeric material.
18. The engine of claim 17 , in which the piston rod is a flexible rod.
19. The engine of claim 16 , the piston rod further including a disc-shaped section on the first end, the disc-shaped section being retained in the resiliently deformable boot and secured to the back of the crown, with at least a portion of the resiliently deformable boot located between the disc-shaped section and the back of the crown.