# US 2021/0340905 A1 · Device for Varying a Compression Ratio, Reciprocating-Piston Internal Combustion Engine and Working Device

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- Number: US 2021/0340905 A1
- Document ID: US20210340905A1
- Status: Published application
- Kind: A1
- Application number: 17/284,296
- Filed: 2019-10-16
- Published: 2021-11-04
- Earliest claimed: 2018-11-14
- Assignees: Bayerische Motoren Werke Aktiengesellschaft
- Applicants: Bayerische Motoren Werke Aktiengesellschaft
- Inventors: Ulrich GUTZER
- Web page: https://patentgrep.com/patent/US20210340905A1

## CPC

- F02B 75/048: {by means of a variable crank stroke length}
- F02D 15/02: by alteration or displacement of piston stroke
- F16C 3/28: Adjustable cranks or eccentrics
- F02B: INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL (gas-turbine plants F02C; hot-gas or combustion-product positive-displacement engine plants F02G)
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)
- F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS

## Abstract

An apparatus configured to change a compression ratio of a reciprocating piston internal combustion engine includes an externally toothed eccentric, an adjusting unit, and a coupling unit. A first takeoff shaft is coupled mechanically to the external toothing system of the eccentric. A second takeoff shaft is coupled mechanically to the adjusting unit. The first and second takeoff shafts of the coupling unit, the eccentric and/or the adjusting unit are configured for the partial or complete arrangement in the interior of a crankcase of the crankshaft, within an installation space of a web of the crankshaft and/or within an installation space of a counterweight.

## Claims

### Claim at position 1

-11. (canceled)

### Claim 12

An apparatus configured to change a compression ratio of a reciprocating piston internal combustion engine, the apparatus comprising:
an externally toothed eccentric which is configured to be arranged in a rotationally movable manner between a pin journal of a crankshaft of a crank drive and a connecting rod eye of a connecting rod in order to change a stroke height of a piston of the reciprocating piston internal combustion engine, which piston is coupled mechanically to the connecting rod;
an adjusting unit which is coupled mechanically to an external toothing system of the eccentric and is configured to set the eccentric by way of rotation of the eccentric, and
a coupling unit which is configured to couple the eccentric mechanically to the adjusting unit and to first and second takeoff shafts which are arranged parallel to one another, are spaced apart radially from one another, and are coupled mechanically to one another, wherein
the first takeoff shaft is coupled mechanically to the external toothing system of the eccentric,
the second takeoff shaft is coupled mechanically to the adjusting unit, and
the first and second takeoff shafts of the coupling unit, the eccentric and/or the adjusting unit are configured for the partial or complete arrangement in the interior of a crankcase of the crankshaft, within an installation space of a web of the crankshaft and/or within an installation space of a counterweight.

### Claim 13 (depends on 12)

The apparatus according to claim 12, wherein
the adjusting unit has an adjusting gear which is configured as an internal gear with an external toothing system configured to receive an adjusting movement for the eccentric, and is configured with an internal toothing system fixedly with respect to the external toothing system for conjoint rotation for mechanical coupling to the coupling unit,
the coupling unit, the eccentric and/or the adjusting unit are/is configured for the partial or complete arrangement: (i) in the interior of a crankcase of the crankshaft, (ii) within an installation space of a web of the crankshaft, and/or (iii) within an installation space of a counterweight, and/or
the coupling unit is arranged partially or completely in the interior of the installation space of the adjusting gear.

### Claim 14

An apparatus configured to change a compression ratio of a reciprocating piston internal combustion engine, the apparatus comprising:
an externally toothed eccentric which is configured to be arranged in a rotationally movable manner between a pin journal of a crankshaft of a crank drive and a connecting rod eye of a connecting rod in order to change a stroke height of a piston of the reciprocating piston internal combustion engine, which piston is coupled mechanically to the connecting rod,
an adjusting unit which is coupled mechanically to an external toothing system of the eccentric and is configured to set the eccentric via rotation of the eccentric, and
a coupling unit configured to couple the eccentric mechanically to the adjusting unit, wherein
the adjusting unit has an adjusting gear which is configured as an internal gear with an external toothing system configured to receive an adjusting movement for the eccentric, and is configured with an internal toothing system fixedly with respect to the external toothing system for conjoint rotation for mechanical coupling to the coupling unit, and
(i) the coupling unit, the eccentric and/or the adjusting unit are configured for the partial or complete arrangement: (a) in the interior of a crankcase of the crankshaft, (b) within an installation space of a web of the crankshaft, and/or (c) within an installation space of a counterweight, and/or (ii) the coupling unit is arranged partially or completely in the interior of an installation space of the adjusting gear.

### Claim 15 (depends on 14)

The apparatus according to claim 14, wherein when the coupling unit is configured for coupling the eccentric mechanically to the adjusting unit via first and second takeoff shafts which: i) are arranged parallel to one another, ii) are spaced apart radially from one another, and iii) are coupled mechanically to one another.

### Claim 16 (depends on 15)

The apparatus according to claim 15, wherein when the coupling unit is configured as a mechanism unit which circulates partially or completely: (a) in the interior space of the crankcase, (b) in the installation space of a web of the crankshaft, and/or (c) in the installation space of a counterweight,
the first takeoff shaft of the coupling unit is configured to be arranged spaced apart in parallel and radially with respect to a rotational axis of the crankshaft, and has an externally toothed first gearwheel for the rotation of the eccentric, and a second gearwheel which is offset axially and is fixed with respect to the first gearwheel of the first takeoff shaft for conjoint rotation, and/or
the second takeoff shaft of the coupling unit is configured to be arranged spaced apart in parallel and radially with respect to the rotational axis of the crankshaft and with respect to the first takeoff shaft, and an externally toothed first gearwheel is configured so as to mesh with the second gearwheel of the first takeoff shaft and, offset axially and fixedly with respect to the first gearwheel of the second takeoff shaft for conjoint rotation, so as to mesh with an externally toothed second gearwheel.

### Claim 17 (depends on 16)

The apparatus according to claim 16, wherein
the second gearwheel of the second takeoff shaft is arranged so as to mesh on the internal toothing system of the adjusting gear,
the external toothing system of the adjusting gear is arranged so as to engage with an adjusting device, and/or
the adjusting gear is configured for rotatable mounting in the interior space of a crankcase of the reciprocating piston internal combustion engine.

### Claim 18 (depends on 17)

The apparatus according to claim 17, further comprising:
an intermediate mechanism that is configured as part of the coupling unit, with an externally toothed intermediate gearwheel, an intermediate shaft which supports an externally toothed intermediate gearwheel, and/or spaced apart in parallel and radially with respect to the crankshaft axis and/or with respect to the first and second takeoff shaft, wherein
the intermediate mechanism is set up to bring about, indirectly or directly, mechanical coupling and meshing of the first gearwheel of the first takeoff shaft, to/with the external toothing system of the eccentric.

### Claim 19 (depends on 18)

The apparatus according to claim 18, further comprising:
a synchronizing mechanism that is configured as part of the coupling unit and/or an intermediate mechanism, with an externally toothed synchronizing gearwheel, a synchronizing shaft which supports an externally toothed synchronizing gearwheel, and/or spaced apart in parallel and/or in a coinciding manner or radially with respect to the crankshaft axis, with respect to any intermediate shaft and/or with respect to the first and second takeoff shaft, in order to change a compression ratio of further cylinders of the reciprocating piston internal combustion engine, wherein
the synchronizing mechanism is set up to bring about, indirectly or directly, mechanical coupling and meshing of the synchronizing gearwheel to/with the external toothing system of the eccentric in order to be driven by way of this, and in addition to/with the coupling unit, the intermediate mechanism and/or the intermediate gearwheel in order to drive the eccentric.

### Claim 20 (depends on 19)

A reciprocating piston internal combustion engine, comprising:
the apparatus according to claim 19 configured to change a compression ratio of the reciprocating piston internal combustion engine;
a crank drive with a crankshaft with at least one pin journal which is mounted on both sides in a rotationally movable manner; and
the pin journal:
(i) being operatively connected to a connecting rod and a piston which is arranged in a cylinder of the reciprocating piston internal combustion engine such that it is slidingly movable, and
(ii) being configured for the conversion of a rotational movement of the crankshaft into a bidirectional, translational movement of the piston with a defined stroke height.

### Claim 21 (depends on 20)

The reciprocating piston internal combustion engine according to claim 20, wherein:
(a) an eccentric of the crank drive rotates with a relative and/or controllably adjustable phase and/or relative rotational speed with respect to the rotation of the crankshaft, with a factor of +½ with respect to the rotational speed of the crankshaft,
(b) toothing systems ensure said ratios via meshing with a stationary adjusting gear of the apparatus for changing a compression ratio, and/or
(c) the phase angle of the rotation of the eccentric and therefore the setting of the compression ratio is brought about via a rotation of the adjusting gear via the adjusting device of the apparatus for changing a compression ratio, and
(d) the eccentric is set via a correspondingly present rotational angle relative to the ignition time via a resulting compression.

### Claim 22 (depends on 21)

A working apparatus with a reciprocating piston internal combustion engine which is configured as a drive means for an assembly of the working apparatus according to claim 21.