Apparatus and method for controlling engine stop of hybrid electric vehicle

• US 9,764,732 B2
• Filed: 11/02/2015
• Issued: 09/19/2017
• Est. Priority Date: 03/30/2015
• Status: Active Grant

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Inventors: Kim, Sang Joon, Oh, Jong Bum, Kim, Sung Deok, Park, Il Kwon, Park, Seong Ik
• Primary Examiner(s): Sweeney, Brian P
• Application Number:
  US14/930,188
• Publication Number:
  US 20160288782A1
• Time in Patent Office: 687 Days
• Field of Search: 701 22
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/485 Motor-assist type
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 20/17 for noise reduction
• CPC Class Codes: 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
• CPC Class Codes: B60W 2030/206 related or induced by the engine
• CPC Class Codes: B60W 2510/06 Combustion engines, Gas turbines
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 2710/244 Charge state
• CPC Class Codes: F02N 11/0814 comprising means for controlling automatic idle-start-stop
• CPC Class Codes: F02N 11/0862 characterised by the electrical power supply means, e.g. battery
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

An apparatus and method for controlling an engine stop of a hybrid electric vehicle provides an efficient torque in the operation of a hybrid starter generator, by applying a torque of a high efficiency point of the hybrid starter generator according to a drop of engine RPM when the engine is stopped, so as to improve fuel efficiency of a vehicle and damping vibration of the vehicle when the engine is stopped, by generating a negative torque on the hybrid starter generator side in accordance with the drop of the engine RPM when the engine is stopped, and by applying a torque of the point that gives the maximum charging power of the battery through the generated negative torque.

Claims

1. A control unit of an apparatus comprising an engine that provides output to a hybrid vehicle;

a hybrid starter generator configured to absorb engine torque; and

a battery connected to the hybrid starter generator, wherein the control unit for controlling an engine stop of a hybrid vehicle is configured to;

control whether the engine is driven, and the torque generation of the hybrid starter generator;

execute a negative torque command of the hybrid starter generator to stop the engine by absorbing the engine torque during stopping of the engine;

set a profile so that a magnitude of an instantaneous charging energy becomes maximum as a result of a hybrid starter generator efficiency and an efficiency of the battery depending on an engine RPM; and

provide the torque of the hybrid starter generator depending on the profile.

2. The control unit of claim 1, wherein the control unit executes charging of the battery connected to the hybrid starter generator when performing the negative torque command of the hybrid starter generator so as to absorb the engine torque.

3. The control unit of claim 1, wherein the apparatus further includes:

an electronic engine mount for damping vibration when the engine is stopped.

4. The control unit of claim 3, wherein the control unit controls the vibration of the vehicle, by interlocking a quantity of vibration damping of the electronic engine mount with a quantity of the negative torque provided from the hybrid starter generator.

5. A method for controlling an engine stop of a hybrid vehicle, the method comprising the steps of:

determining, by a control unit, whether an engine power drive shaft is disconnected and a fuel injection of the engine is stopped when an engine of the hybrid vehicle is stopped;

generating, by the control unit, a negative torque in the hybrid starter generator, depending on a profile that is set so that a magnitude of an instantaneous charging energy of the battery becomes maximum, as a result of a hybrid starter generator efficiency and a battery efficiency depending on an engine RPM when the engine power drive shaft is disconnected and the fuel injection of the engine is stopped; and

determining, by the control unit, whether the engine RPM is less than a preset reference value by the generated torque of the hybrid starter generator.

6. The method of claim 5, wherein the step of generating the negative torque further comprises:

executing, by the control unit, charging of a battery connected to the hybrid starter generator.

7. The method of claim 5, wherein the step of generating the negative torque further comprises:

damping, by the control unit, a vibration when the engine is stopped through an electronic engine mount.

8. The method of claim 7, further comprising the step of:

controlling, by the control unit, the vibration of the vehicle, by interlocking a quantity of vibration damping of the electronic engine mount with a quantity of negative torque provided by the hybrid starter generator.