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Opposed piston engine cam shape

  • US 10,465,516 B1
  • Filed: 03/04/2019
  • Issued: 11/05/2019
  • Est. Priority Date: 11/07/2018
  • Status: Active Grant
First Claim
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1. An internal combustion engine comprising:

  • a driveshaft having a first end and a second end and disposed along a driveshaft axis;

    a first cam mounted on the driveshaft, the first cam having a cam hub attached the driveshaft, and a circumferential cam shoulder extending around a periphery of the hub, the cam shoulder having a first cam diameter and a first segmented polynomial shape, the shoulder having at least two lobes formed by the polynomial shape, each lobe characterized by a peak positioned between a first trough and a second trough and a lobe wavelength between the two troughs, the peak having a maximum amplitude for the lobe, where the wavelength distance from the first trough to peak of an ascending shoulder portion of the lobe is greater than the wavelength distance from the peak to the second trough of a descending shoulder portion of the lobe;

    a second cam mounted on the driveshaft spaced apart from the first cam, the second cam having a cam hub attached the driveshaft, and a circumferential cam shoulder extending around a periphery of the hub, the cam shoulder having a second segmented polynomial shape of constantly changing slope which second segmented polynomial shape has the same frequency as the first segmented polynomial shape, the shoulder having at least two lobes formed by the second polynomial shape, each lobe characterized by a peak positioned between a first trough and a second trough and a lobe wavelength between the two troughs, the peak having a maximum amplitude for the lobe, where the wavelength distance from the first trough to peak of an ascending shoulder portion of the lobe is greater than the wavelength distance from the peak to the second trough of a descending shoulder portion of the lobe,wherein the number of lobes of the second cam corresponds with the number of lobes of the first cam;

    a first combustion cylinder defined along a center cylinder axis, the combustion cylinder having a first end and a second end with an intake port formed in the cylinder between the first and second ends and an exhaust port formed in the cylinder between the intake port and the second end, the center cylinder axis being parallel with but spaced apart from the driveshaft axis, wherein a combustion chamber is defined within the cylinder between the two cylinder ends;

    a first piston assembly disposed in the first cylinder end of the first combustion cylinder and an opposing second piston assembly disposed in the second cylinder end of the first combustion cylinder, the first piston assembly engaging the segmented polynomial shaped shoulder of the first cam and the second piston assembly engaging the segmented polynomial shaped shoulder of the second cam, each piston assembly movable between an inner dead center (IDC) position in which the piston assembly is fully extended in the combustion chamber away from its corresponding cam and an outer dead center position in which the piston assembly is fully retracted in the combustion chamber away from the inner dead center position; and

    at least one fuel injector disposed adjacent a center of the combustion cylinder and in communication with said combustion chamber,andwherein the cams oppose one another so that the peak of a lobe of the first cam is substantially aligned with the peak of a lobe of the second cam, but no portion of first segmented polynomial shaped shoulder is parallel with a portion of second segmented polynomial shaped shoulder.

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