# US 12,110,006 B2 · System and method for controlling limp-home reverse traveling of hybrid electric vehicle

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- Number: US 12,110,006 B2
- Document ID: US12110006B2
- Status: Granted
- Kind: B2
- Application number: 17/832,048
- Filed: 2022-06-03
- Published: 2023-01-05
- Granted: 2024-10-08
- Earliest claimed: 2021-06-30
- Assignees: Hyundai Motor Company; Kia Corporation
- Applicants: Hyundai Motor Company; Kia Corporation
- Inventors: Jeong Won Rho; Chil Seong Park
- Web page: https://patentgrep.com/patent/US12110006B2

## CPC

- B60K 6/48: Parallel type
- B60W 20/50: Control strategies for responding to system failures, e.g. for fault diagnosis, failsafe operation or limp mode
- B60K 6/442: Series-parallel switching type
- B60W 10/02: including control of driveline clutches
- B60W 10/06: including control of combustion engines
- B60W 10/08: including control of electric propulsion units, e.g. motors or generators
- B60W 30/18036: {Reversing}
- B60K 2006/268: {Electric drive motor starts the engine, i.e. used as starter motor}
- B60K 2006/4825: {Electric machine connected or connectable to gearbox input shaft}
- B60W 2050/0012: {Feedforward or open loop systems}
- B60W 2510/0638: Engine speed
- B60W 2510/242: for electrical energy
- B60W 2510/30: Auxiliary equipments
- 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 system for operating a hybrid electric vehicle includes a hybrid starter generator generating a counter-electromotive force while rotating with an engine when conditions are satisfied, including where starting of the engine is secured, a main relay is turned off, and an engine clutch is opened according to a request for reverse traveling, in a state where a component of a high-voltage system is failed, a motor reversely rotating using the counter-electromotive force of the hybrid starter generator, an electronic load component operated using the counter-electromotive force of the hybrid starter generator, and a controller determining an engine speed required by load output values according to operations of the motor and the electronic load component, and restricting the operation of the motor or the electronic load component according to a determined engine speed.

## Claims

### Claim 1

A system for operating a hybrid electric vehicle having a transmission excluding a reverse stage, the system comprising:
a hybrid starter generator configured to generate a counter-electromotive force while rotating with an engine when conditions where starting of the engine is secured, a main relay is turned off, and an engine clutch is opened according to a request for reverse traveling are satisfied in a state where a component of a high-voltage system is failed;
a motor configured to be reversely rotated using the counter-electromotive force of the hybrid starter generator for reverse traveling;
an electronic load component configured to be operated using the counter-electromotive force of the hybrid starter generator; and
a controller configured to determine an engine speed required by load output values according to operations of the motor and the electronic load component, and to restrict the operation of the motor or the electronic load component according to a determined engine speed.

### Claim 2 (depends on 1)

The system of claim 1, wherein the controller comprises:
a load output calculator configured to calculate the load output value according to the operations of the motor and the electronic load component; and
an engine speed controller configured to determine the engine speed required by the load output value calculated by the load output calculator, and to output a signal for restricting the operation of the motor or the electronic load component when the determined engine speed is equal to or higher than a reference speed.

### Claim 3 (depends on 2)

The system of claim 2, wherein the load output calculator is configured to calculate the load output value by summing the load output values according to the operations of the motor and the electronic load components, and then to input the calculated load output values to the engine speed controller by a feedforward control method.

### Claim 4 (depends on 2)

The system of claim 2, wherein the engine speed controller comprises an engine speed map for each load output constructed for determining the engine speed required by the load output value calculated by the load output calculator.

### Claim 5

A method for operating a hybrid electric vehicle having a transmission excluding a reverse stage, the method comprising:
generating a counter-electromotive force by a hybrid starter generator rotating with an engine when conditions are satisfied, including where starting of the engine is secured, a main relay is turned off, and an engine clutch is opened according to a request for reverse traveling, in a state where a component of a high-voltage system is failed;
reversely rotating a motor using the counter-electromotive force of the hybrid starter generator for reverse traveling;
operating an electronic load component using the counter-electromotive force of the hybrid starter generator; and
determining an engine speed required by load output values according to operations of the motor and the electronic load component, and restricting the operation of the motor or the electronic load component according to a determined engine speed.

### Claim 6 (depends on 5)

The method of claim 5, wherein determining the engine speed required by the load output values, and the restricting of the operation of the motor or the electronic load component according to the determined engine speed comprises:
calculating the load output value according to the operations of the motor and the electronic load component; and
determining the engine speed required by the calculated load output values, and restricting the operation of the motor or the electronic load component when the determined engine speed is equal to or higher than a reference speed.

### Claim 7 (depends on 6)

The method of claim 6, wherein calculating the load output value comprises calculating by summing the load output values according to the operations of the motor and the electronic load component.

### Claim 8 (depends on 6)

The method of claim 6, further comprising inputting the load output value to an engine speed controller by a feedforward control method.

### Claim 9 (depends on 6)

The method of claim 6, wherein determining the engine speed comprises determining the engine speed required by the load output value based on an engine speed map for each load output constructed through a test in advance.

### Claim 10 (depends on 9)

The method of claim 9, further comprising:
comparing the determined engine speed with the reference speed; and
outputting a signal for restricting the operation of the motor or the electronic load component in response to the engine speed exceeding the reference speed.

### Claim 11 (depends on 10)

The method of claim 10, wherein when the operation of the motor or the electronic load component is restricted in response to the signal, a current output of the motor is controlled to be equal to or less than a reference value, and simultaneously, a PWM control for a constant voltage control performed with respect to the counter-electromotive force of the hybrid starter generator is not released and continues.

### Claim 12 (depends on 10)

The method of claim 10, wherein the operations of the motor and the electronic load component are maintained without restricting the operation of the motor or the electronic load component in response to the determined engine speed being less than or equal to the reference speed.

### Claim 13

A method of operating a hybrid electric vehicle having a transmission excluding a reverse stage, the method comprising:
confirming failure of a component of a high-voltage system;
starting an engine;
turning off a main relay;
opening an engine clutch;
reversely rotating a motor using counter-electromotive force of a hybrid starter generator for reverse traveling;
operating an electronic load component;
calculating a load output value of the motor and the electronic load component;
determining an engine speed required by the calculated load output value;
determining whether the determined engine speed is greater than a reference speed;
in response to determining the determined engine speed is greater than the reference speed, outputting a signal for restricting operation of the motor or the electronic load component; and
in response to determining the determined engine speed is less than or equal to the reference speed, continuing operations of the motor and the electronic load component.

### Claim 14 (depends on 13)

The method of claim 13, wherein calculating the load output value comprises calculating by summing the load output values according to operations of the motor and the electronic load component.

### Claim 15 (depends on 13)

The method of claim 13, further comprising inputting the load output value to an engine speed controller by a feedforward control method.

### Claim 16 (depends on 13)

The method of claim 13, wherein determining the engine speed comprises determining the engine speed required by the load output value based on an engine speed map for each load output constructed through a test in advance.

### Claim 17 (depends on 13)

The method of claim 13, wherein the component of the high-voltage system comprises a high-voltage battery.

### Claim 18 (depends on 13)

The method of claim 13, wherein operating the electronic load component comprises providing voltage stored in a DC-link capacitor to the electronic load component.

### Claim 19 (depends on 18)

The method of claim 18, wherein the electronic load component comprises a low voltage DC/DC converter or an air conditioner compressor.

### Claim 20 (depends on 18)

The method of claim 18, wherein operating the electronic load component comprises charging an auxiliary battery of the electronic load component.