# US 10,479,345 B2 · Method of decoupling input and output torque for engine speed control and hybrid powertrain utilizing same

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- Number: US 10,479,345 B2
- Document ID: US10479345B2
- Status: Granted
- Kind: B2
- Application number: 15/673,716
- Filed: 2017-08-10
- Published: 2019-02-14
- Granted: 2019-11-19
- Earliest claimed: 2017-08-10
- Assignees: GM Global Technology Operations LLC
- Applicants: GM Global Technology Operations LLC
- Inventors: Shaochun Ye
- Web page: https://patentgrep.com/patent/US10479345B2

## CPC

- B60K 6/445: Differential gearing distribution type
- B60W 20/11: using model predictive control [MPC] strategies, i.e. control methods based on models predicting performance {(utilising navigation and traffic information in the control strategy B60W20/12)}
- B60K 6/365: with the gears having orbital motion
- B60K 6/387: Actuated clutches, i.e. clutches engaged or disengaged by electric, hydraulic or mechanical actuating means
- B60W 10/06: including control of combustion engines
- B60W 10/08: including control of electric propulsion units, e.g. motors or generators
- B60W 10/115: with planetary gears
- B60W 20/15: Control strategies specially adapted for achieving a particular effect
- B60W 20/40: Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers {(power-up or power-down of the driveline B60W30/192)}
- B60W 30/182: Selecting between different operative modes, e.g. comfort and performance modes
- B60K 2006/381: {characterized by driveline brakes}
- B60W 2050/0041: {of the drive line}
- B60W 2050/0075: {Automatic parameter input, automatic initialising or calibrating means}
- B60W 2510/0652: Speed change rate
- B60W 2710/0644: Engine speed
- B60W 2710/083: Torque
- B60W 2710/1022: Input torque
- B60W 2710/1044: Output speed change rate
- B60W 2710/1055: Output torque change rate
- Y02T 10/62: Hybrid vehicles
- B60K: ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A method of decoupling output torque from input torque during engine speed control of a hybrid powertrain for a vehicle comprises determining, via a controller, a virtual output torque required on an output member of a multi-mode transmission given a virtual input torque commanded on an input member of the multi-mode transmission for engine speed control in a selected mode of the multi-mode transmission such that rotational speed of the output member is unchanged to prevent undesired torque variation at the output member. The controller determines the virtual output torque via a first stored transfer function relating virtual output torque to virtual input torque based on modeled physical dynamics of the vehicle driveline for the selected mode of the multi-mode transmission. A hybrid powertrain includes an engine and a hybrid transmission, and a controller that controls the hybrid transmission according to the method.

## Claims

### Claim 1

A method of decoupling output torque from input torque during engine speed control of a hybrid powertrain for a vehicle, the method comprising:
determining via a controller a virtual output torque required on an output member of a multi-mode transmission given a virtual input torque for engine speed control commanded on an input member of the multi-mode transmission in a selected mode of the multi-mode transmission such that rotational speed of the output member is unchanged to prevent undesired torque variation at the output member; and
wherein the determining of the virtual output torque is via a first stored transfer function relating virtual output torque to virtual input torque, and the first stored transfer function is based on modeled physical dynamics of a driveline of the vehicle for the selected mode of the multi-mode transmission.

### Claim 2 (depends on 1)

The method of claim 1, wherein the modeled physical dynamics of the driveline include spring functions, damper functions, and inertial mass values representative of components of the driveline in the selected mode.

### Claim 3 (depends on 2)

The method of claim 2, wherein the modeled physical dynamics of the driveline are represented as a state space model.

### Claim 4 (depends on 1)

The method of claim 1, wherein the powertrain includes an engine operatively connected to the input member, the method further comprising:
commanding the virtual input torque at least partially according to an engine speed profile.

### Claim 5 (depends on 4)

The method of claim 4, wherein the multi-mode transmission includes multiple motor/generators controllable to apply physical torque to respective components of the multi-mode transmission resulting in torque at the input member equal to the virtual input torque, and torque at the output member equal to the virtual output torque, the method further comprising:
transforming, via the controller, the virtual input torque and the virtual output torque to respective torques of the multiple motor/generators according to a second stored transfer function; and
controlling the multiple motor/generators to provide the respective torques.

### Claim 6 (depends on 4)

The method of claim 4, wherein the powertrain includes an engine operatively connected to the input member, and further comprising:
monitoring vehicle operating conditions;
determining that the vehicle operating conditions warrant an engine speed control event; and
wherein the commanding the virtual input torque is in response to determining that the vehicle operating conditions warrant an engine start event.

### Claim 7 (depends on 1)

The method of claim 1, wherein the multi-mode transmission includes at least two planetary gear sets, a first selectively engageable torque-transmitting mechanism, and a second selectively engageable torque-transmitting mechanism;
wherein each of the torque-transmitting mechanisms is selectively engageable to connect a respective member of one of the planetary gear sets to another member of one of the planetary gear sets or to a stationary member; and
wherein the first torque-transmitting mechanism is engaged and the second torque-transmitting mechanism is disengaged in a first operating mode of the transmission, and the second of the torque-transmitting mechanism is engaged and the first torque-transmitting mechanism is disengaged in a second operating mode of the transmission.

### Claim 8 (depends on 7)

The method of claim 7, wherein the multi-mode transmission includes a first motor/generator and a second motor/generator, and is controllable by the controller to provide three electric vehicle modes, including a first electric vehicle mode in which the second motor/generator provides torque at the output member and the first motor/generator does not, a second electric vehicle mode in which both the first motor/generator and the second motor/generator provide torque at the output member, and a third electric vehicle mode in which the first motor/generator provides torque at the output member and the second motor/generator does not.

### Claim 9

A hybrid powertrain for a vehicle comprising:
a multi-mode transmission having an input member and an output member;
a controller operatively connected to the multi-mode transmission and configured to execute a stored algorithm that includes a first stored transfer function relating virtual output torque to virtual input torque, and the first stored transfer function is based on modeled physical dynamics of a driveline of the vehicle for each selected mode of the multi-mode transmission;
wherein, via the stored algorithm, the controller:
commands the virtual input torque; and
determines the virtual output torque required on the output member given the virtual input torque commanded on the input member for engine speed control in the selected mode of the multi-mode transmission such that rotational speed of the output member is unchanged to prevent undesired torque variation at the output member.

### Claim 10 (depends on 9)

The hybrid powertrain of claim 9, wherein the modeled physical dynamics include spring functions, damper functions, and inertial mass values representative of components of the driveline in the selected mode.

### Claim 11 (depends on 10)

The hybrid powertrain of claim 10, wherein the modeled physical dynamics are represented as a state space model.

### Claim 12 (depends on 9)

The hybrid powertrain of claim 9, further comprising:
an engine operatively connected to the input member; and wherein the stored algorithm is configured to command the virtual input torque at least partially according to a predetermined speed profile of the engine.

### Claim 13 (depends on 9)

The hybrid powertrain of claim 9, wherein the multi-mode transmission includes multiple motor/generators controllable to apply physical torque to respective components of the multi-mode transmission resulting in torque at the input member equal to the virtual input torque, and torque at the output member equal to the virtual output torque; and
wherein the controller is configured to:
transform, via the stored algorithm, the virtual input torque and the virtual output torque to respective torques of the multiple motor/generators according to a second stored transfer function; and
control the multiple motor/generators to provide the respective torques.

### Claim 14 (depends on 9)

The hybrid powertrain of claim 9, further comprising:
an engine operatively connected to the input member and
wherein the stored algorithm is configured to:
monitor vehicle operating conditions;
determine that the vehicle operating conditions warrant an engine speed control event; and
wherein the commanding the virtual input torque is in response to determining that the vehicle operating conditions warrant an engine speed control event.

### Claim 15 (depends on 9)

The hybrid powertrain of claim 9, wherein the multi-mode transmission includes at least two planetary gear sets, a first selectively engageable torque-transmitting mechanism, and a second selectively engageable torque-transmitting mechanism;
wherein each of the torque-transmitting mechanisms is selectively engageable to connect a respective member of one of the planetary gear sets to another member of one of the planetary gear sets or to a stationary member; and
wherein the first torque-transmitting mechanism is engaged and the second torque-transmitting mechanism is disengaged in a first operating mode of the transmission, and the second of the torque-transmitting mechanism is engaged and the first torque-transmitting mechanism is disengaged in a second operating mode of the transmission.

### Claim 16 (depends on 15)

The hybrid powertrain of claim 15, wherein the multi-mode transmission includes a first motor/generator and a second motor/generator, and is controllable by the controller to provide three electric vehicle modes, including a first electric vehicle mode in which the second motor/generator provides torque at the output member and the first motor/generator does not, a second electric vehicle mode in which both the first motor/generator and the second motor/generator provide torque at the output member, and a third electric vehicle mode in which the first motor/generator provides torque at the output member and the second motor/generator does not.

### Claim 17

A vehicle comprising:
a hybrid powertrain including:
an engine having a crankshaft;
a multi-mode transmission having an input member connectable to rotate with the crankshaft, and having an output member; and
a controller operatively connected to the multi-mode transmission and configured to execute a stored algorithm that includes a first stored transfer function relating virtual output torque to virtual input torque, and the first stored transfer function is based on modeled physical dynamics of a driveline of the vehicle for each selected mode of the multi-mode transmission;
wherein the modeled physical dynamics include spring functions, damper functions, and inertial mass values representative of components of the driveline in the selected mode, and are represented as a state space model;
wherein, via the stored algorithm, the controller:
commands the virtual input torque; and
determines the virtual output torque required on the output member given the virtual input torque commanded on the input member for engine speed control in the selected mode of the multi-mode transmission such that rotational speed of the output member is unchanged to prevent undesired torque variation at the output member.

### Claim 18 (depends on 17)

The vehicle of claim 17, wherein the stored algorithm is configured to command the virtual input torque at least partially according to a predetermined speed profile of the engine.

### Claim 19 (depends on 17)

The vehicle of claim 17, wherein the multi-mode transmission includes multiple motor/generators controllable to apply physical torque to respective components of the multi-mode transmission resulting in torque at the input member equal to the virtual input torque, and torque at the output member equal to the virtual output torque; and
wherein the controller is configured to:
transform, via the stored algorithm, the virtual input torque and the virtual output torque to respective torques of the multiple motor/generators according to a second stored transfer function; and
control the multiple motor/generators to provide the respective torques.

### Claim 20 (depends on 19)

The vehicle of claim 19, wherein the multi-mode transmission includes a first motor/generator and a second motor/generator, and is controllable by the controller to provide three electric vehicle modes, including a first electric vehicle mode in which the second motor/generator provides torque at the output member and the first motor/generator does not, a second electric vehicle mode in which both the first motor/generator and the second motor/generator provide torque at the output member, and a third electric vehicle mode in which the first motor/generator provides torque at the output member and the second motor/generator does not.