Eccentric shaft speed change mechanism

Patent metadata

Field	Value
Publication number	US-11268437-B2
Application number	US-201916375423-A
Country	US
Kind code	B2
Filing date	Apr 4, 2019
Priority date	Apr 4, 2019
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

A crankshaft is rotatably supported by an engine block and rotatable about a crank axis. An eccentric shaft is rotatably supported within the engine and rotatable about an eccentric shaft axis, wherein the eccentric shaft axis is parallel to and distal from the crank axis. A speed change mechanism interlinks movement of the eccentric shaft and the crankshaft. The speed change mechanism selectively varies a ratio of a rotational speed of the eccentric shaft relative to a rotational speed of the crankshaft from 1:1 to one of: −8:1, −6:1, −4:1, −2:1, −1:1, −0.5:1, 0:1, 0.5:1, 1:1, 2:1, 4:1, 6:1, and 8:1, thereby causing the eccentric shaft to rotate at a speed different from the crankshaft and varying a rotational position of the eccentric shaft relative to the crankshaft.

First claim

What is claimed is:

1. An internal combustion engine comprising:
an engine block defining a cylinder bore;
a piston slidably supported within the cylinder bore, wherein the piston slides reciprocally within the cylinder bore throughout an engine cycle, including a piston compression stroke having a compression stroke length and a piston expansion stroke having an expansion stroke length;
a crankshaft rotatably supported by the engine block and rotatable about a crank axis;
an eccentric shaft rotatably supported within the engine and rotatable about an eccentric shaft axis, wherein the eccentric shaft axis is parallel to and distal from the crank axis;
a speed change mechanism interlinking movement of the eccentric shaft and the crankshaft,
wherein the speed change mechanism selectively varies a ratio of a rotational speed of the eccentric shaft relative to a rotational speed of the crankshaft from 1:1 to one of: −8:1, −6:1, −4:1, −2:1, −1:1, −0.5:1, 0:1, 0.5:1, 1:1, 2:1, 4:1, 6:1, and 8:1, thereby causing the eccentric shaft to rotate at a speed different from the crankshaft and varying a rotational position of the eccentric shaft relative to the crankshaft, wherein the speed change mechanism includes an interference clutch having:
a clutch actuator;
a clutch plate disposed coaxially on the eccentric shaft between a stationary ground element and a drive element of the engine, the clutch actuator adapted to move the clutch plate axially along the eccentric shaft between a first position and a second position;
a first synchronizer mounted onto the clutch plate, facing the stationary ground element;
a second synchronizer mounted onto the clutch plate, facing the drive element of the engine; and
one or more interference elements extending outward from the clutch plate;
wherein the clutch actuator selectively moves the clutch plate between the first position and the second position, wherein the clutch actuator moves the clutch plate into the first position, wherein the clutch actuator moves the clutch plate toward the stationary ground element, the first synchronizer frictionally engages the stationary ground element to synchronize the rotational speed of the eccentric shaft to the rotational speed of the stationary ground element, and at least one of the interference elements engages the stationary ground element to rotationally lock the eccentric shaft to the stationary ground element, and wherein the clutch actuator moves the clutch plate to the second position, wherein the clutch actuator moves the clutch plate toward the drive element of the engine, the second synchronizer frictionally engages the drive element of the engine to synchronize the rotational speed of the eccentric shaft to the rotational speed of the drive element of the engine, and at least one of the interference elements engages the drive element to rotationally lock the eccentric shaft to the drive element, wherein the rotational speed of the drive element of the engine is greater than the rotational speed of the stationary ground element.

2. The internal combustion engine of claim 1 wherein the rotational speed of the stationary ground element is zero, and the rotational speed of the drive element of the engine is one half the rotational speed of the crankshaft.

3. The internal combustion engine of claim 1 wherein the drive element further comprises:
a phaser that selectively adjusts a rotational position of the eccentric shaft relative to the crankshaft and infinitely adjusts a compression ratio of the internal combustion engine between a first predetermined compression ratio and a second predetermined compression ratio greater than the first predetermined compression ratio.

4. The internal combustion engine of claim 1 wherein the drive element further comprises:
a gearbox; and
a phaser,
wherein the gearbox is disposed on and coaxial with the eccentric shaft and selectively rotates the eccentric shaft at a rotational speed that is one of: one half of the rotational speed of the crankshaft, and the same as the rotational speed of the crankshaft, and wherein the phaser is disposed on and coaxial with the eccentric shaft, and selectively alters a rotational position of the eccentric shaft relative to a rotational position of the crankshaft to adjust a compression ratio of the internal combustion engine.

5. The internal combustion engine of claim 4 wherein the phaser adjusts a stroke length and a top dead center position of the piston inside the cylinder bore between at least a first length with a first top dead center position and a second length with a second top dead center position, the first length is smaller than the second length, the first top dead center position is between the second top dead center position and the crankshaft, the first length defines a first predetermined compression ratio and the second length defines a second predetermined compression ratio greater than the first predetermined compression ratio, and wherein the gearbox is one of a harmonic drive, a planetary gearset, and a roller reducer.

6. The internal combustion engine of claim 1 wherein the drive element further includes:
a gearbox rotatably supported by the engine block and coaxial with the eccentric shaft; and
a clutch housing supported coaxially on the eccentric shaft;
a clutch plate rotatably engaged with the eccentric shaft and moveable axially along the eccentric shaft within the clutch housing, the clutch plate including at least one interference element extending outward from the clutch plate; and
a clutch actuator adapted to move the clutch plate axially along the eccentric shaft within the clutch housing,
wherein the clutch actuator selectively moves the clutch plate between a first position and a second position, wherein in the first position the at least one interference element of the clutch plate engages the clutch housing in a first rotational orientation and eliminates a difference in rotational speed between the eccentric shaft and the clutch housing, wherein in the second position the at least one interference element of the clutch plate engages with the clutch housing in a second rotational orientation different than the first rotational orientation and eliminates a difference in rotational speed between the eccentric shaft and the clutch housing, and wherein the gearbox selectively rotates the eccentric shaft at a rotational speed that is one of: one half of the rotational speed of the crankshaft, and the same as the rotational speed of the crankshaft.

7. The internal combustion engine of claim 6 wherein a phaser adjusts a stroke length and a top dead center position of the piston inside the cylinder bore between at least a first length with a first top dead center position and a second length with a second top dead center position, the first length is smaller than the second length, the first top dead center position is between the second top dead center position and the crankshaft, the first length defines a first predetermined compression ratio and the second length defines a second predetermined compression ratio greater than the first predetermined compression ratio, and wherein the gearbox is one of a harmonic drive, a planetary gearset, and a roller reducer.

8. The internal combustion engine of claim 1 wherein the drive element further includes:
an input shaft rotatably supported by the engine block and parallel to the eccentric shaft;
a plurality of input shaft gears rotatably disposed on the input shaft;
a clutch plate disposed coaxially on the input shaft axially between the plurality of input shaft gears, the clutch plate including one or more interference elements extending outward from the clutch plate;
a first synchronizer disposed on the clutch pla

Assignees

• Gm Global Tech Operations Llc

Inventors

• Gautier Erwan
• Ketterer Justin
• Heinbuch Ryan

Classifications

• F02B75/048 Primary

  by means of a variable crank stroke length · CPC title

• F02D15/02

  by alteration or displacement of piston stroke · CPC title

• F02B75/045 Primary

  by means of a variable connecting rod length · CPC title