Method of controlling engine speed of hybrid vehicle

Patent metadata

Field	Value
Publication number	US-10023183-B2
Application number	US-201414546693-A
Country	US
Kind code	B2
Filing date	Nov 18, 2014
Priority date	Sep 23, 2014
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

A method of controlling an engine speed of a hybrid vehicle including a motor that is connected to a transmission, a battery that provides a driving voltage to the motor, an engine that is selectively connected to the motor through an engine clutch, and a hybrid starter-generator (HSG) that is connected to the engine includes: comparing, when the engine is started, an external air temperature to a setting temperature; setting a battery rated derating factor based on the comparison of the external air temperature to the setting temperature; determining an output area of the HSG according to a battery voltage; and outputting an available torque of the HSG based on the set battery rated derating factor and the determined HSG output area.

First claim

What is claimed is:

1. A method of controlling an engine speed of a hybrid vehicle including a motor that is connected to a transmission, a battery that provides a driving voltage to the motor, an engine that is selectively connected to the motor through an engine clutch, and a hybrid starter-generator (HSG) that is connected to the engine, the method comprising:
comparing an external air temperature to a predetermined temperature when the engine is started;
setting a rated derating factor of the battery based on the comparison of the external air temperature to the predetermined temperature;
determining an output area of the HSG according to a battery voltage;
outputting an available torque of the HSG based on the set rated derating factor of the battery and the determined output area of the HSG; and
setting the rated derating factor of the battery as less than 1 when the external air temperature is less than the predetermined temperature, and setting the rated derating factor of the battery as 1 when the external air temperature is greater than or equal to the predetermined temperature.

2. The method of claim 1 , further comprising:
applying a minimum output area of the HSG when the battery voltage is less than a first predetermined voltage;
applying an intermediate output area of the HSG when the battery voltage is equal to or greater than the first predetermined voltage and is less than a second predetermined voltage; and
applying a maximum output area of the HSG when the battery voltage is equal to or greater than the second predetermined voltage.

3. The method of claim 1 , further comprising:
cranking the engine with the output torque of the HSG; and
increasing an engine speed with only the available torque of the HSG without fuel injection until the engine speed is synchronized with a motor speed.

4. The method of claim 3 , further comprising generating an engine torque by coupling the engine clutch and ejecting fuel when the engine speed is synchronized with the motor speed.

5. The method of claim 1 , further comprising:
calculating a torque for synchronizing the engine speed with the motor speed when a driving mode of the hybrid vehicle is converted from an electric vehicle (EV) mode to hybrid electric vehicle (HEV) mode;
comparing the available torque of the HSG to the torque for synchronizing the engine speed with the motor speed; and
maintaining the EV mode when the available torque of the HSG is greater than the torque for synchronizing the engine speed with the motor speed.

6. The method of claim 5 , further comprising converting to the HEV mode when the available torque of the HSG is equal to or less than the torque for synchronizing the engine speed with the motor speed.

7. The method of claim 6 , wherein the converting to the HEV mode comprises increasing the engine speed with the available torque of the HSG and generating the engine torque after increasing the engine speed.

Assignees

• Hyundai Motor Co Ltd

Inventors

• Ohn Hyungseuk
• Lim Seongyeop
• Oh Neungseop

Classifications

• B60K2006/4825

  Electric machine connected or connectable to gearbox input shaft · CPC title

• B60K2006/268

  Electric drive motor starts the engine, i.e. used as starter motor · CPC title

• B60K6/387

  Actuated clutches, i.e. clutches engaged or disengaged by electric, hydraulic or mechanical actuating means · CPC title

• B60W2555/20

  Ambient conditions, e.g. wind or rain · CPC title

• B60W30/194

  related to low temperature conditions, e.g. high viscosity of hydraulic fluid · CPC title