Control system and control method of hybrid electric vehicle

• US 10,017,174 B2
• Filed: 09/05/2014
• Issued: 07/10/2018
• Est. Priority Date: 09/09/2013
• Status: Active Grant

• Current Assignee: BYD Company Limited
• Original Assignee: BYD Company Limited
• Inventors: Wang, Jinlong, Chen, Hao, Ruan, Ou
• Primary Examiner(s): Hilgendorf, Dale W
• Application Number:
  US14/917,907
• Publication Number:
  US 20170001624A1
• Time in Patent Office: 1,404 Days
• CPC Class Codes: B60K 2006/4808 Electric machine connected or connectable to gearbox output shaft
• CPC Class Codes: B60K 6/48 Parallel 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 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/10 Controlling the power contribution of each of the prime movers to meet required power demand
• CPC Class Codes: B60W 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 20/15 Control strategies specially adapted for achieving a particular effect
• 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 2510/244 Charge state
• CPC Class Codes: B60W 2520/04 Vehicle stop
• CPC Class Codes: B60W 2540/16 Ratio selector position
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 2710/086 Power
• CPC Class Codes: B60W 30/18018 Start-stop drive, e.g. in a traffic jam
• CPC Class Codes: B60W 30/18054 at stand still, e.g. engine in idling state hill holding B60W30/18118
• CPC Class Codes: B60W 30/182 Selecting between different operative modes, e.g. comfort and performance modes
• CPC Class Codes: B60Y 2300/182 Selecting between different operative modes, e.g. comfort and performance modes
• CPC Class Codes: F02D 2041/224 Diagnosis of the fuel system
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02N 11/0818 : Conditions for starting or stopping the engine or for deactivating the idle-start-stop mode
• CPC Class Codes: F02N 11/0833 : Vehicle conditions F02N11/0822, F02N11/0825 take precedence
• CPC Class Codes: F02N 2200/02 : said parameters being related to the engine
• CPC Class Codes: F02N 2200/023 : Engine temperature
• CPC Class Codes: F02N 2200/062 : Battery current
• CPC Class Codes: F02N 2200/08 : said parameters being related to the vehicle or its components
• CPC Class Codes: F02N 2200/0802 : Transmission state, e.g. gear ratio or neutral state
• CPC Class Codes: Y02T 10/40 : Engine management systems
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y10S 903/93 : Conjoint control of different elements

Abstract

A control system for a hybrid electric vehicle comprises a transmission system configured to drive wheels, an engine power subsystem connected to the transmission system, a motor power subsystem connected to the transmission system and a control module. When vehicle'"'"'s electrical power is on, the control module is configured to control operating mode of the hybrid electric vehicle through the engine power subsystem and the motor power subsystem. The operating mode comprises HEV-eco mode and HEV-s mode. When the hybrid electric vehicle operates in HEV-eco and the hybrid electric vehicle operates at low power or when the hybrid electric vehicle operates in HEV-s mode and when the vehicle speed is zero, the control module enables the hybrid electric vehicle to operate by idle start-stop strategy.

Claims

1. A control system for a hybrid electric vehicle, comprising:

a transmission system configured to drive wheels of the hybrid electric vehicle;

an engine power subsystem connected to the transmission system;

a motor power subsystem connected to the transmission system; and

a control module,

wherein when electrical power of the vehicle is on, the control module is configured to control the hybrid electric vehicle to operate in corresponding operating modes by controlling the engine power subsystem and the motor power subsystem, wherein the operating mode comprises HEV-eco mode and HEV-s mode,

wherein;

(1) when the hybrid electric vehicle operates in HEV-eco and the hybrid electric vehicle operates at low power, or when the hybrid electric vehicle operates in HEV-s mode; and

(2) the vehicle speed is zero,

the control module is further configured to control the hybrid electric vehicle to operate by idle start-stop strategy;

wherein when the hybrid electric vehicle operates in the HEV-eco mode,

under the conditions that a road slope is below a lower limit of slope, electric quantity of a power battery is below a lower limit of the electric quantity, or

under the conditions that the road slope is below the lower limit of the slope and a maximum allowable discharge power of the power battery is below a lower limit of the power,

the control module is configured to control the hybrid electric vehicle to operate in a low power mode.

2. The control system according to claim 1, wherein when the hybrid electric vehicle operates by idle start-stop strategy and an engine is running, the control module is further configured to shut off the engine when all of following conditions is satisfied:

(1) no fault is detected in a high-pressure system;

(2) no fault is detected in a communication system;

(3) a transmission shift lever is in park P;

(4) the maximum allowable discharge power of the power battery in the motor power subsystem exceeds the upper limit of power;

or

(5) water temperature at an engine thermostat is greater than an upper limit of a preset temperature.

3. The control system according to claim 1, wherein when the hybrid electric vehicle operates by idle start-stop strategy and an engine turns off, the control module is further configured to turn on the engine when any of following conditions is satisfied:

(1) a fault has been detected in a high-pressure system;

(2) a fault has been detected in a communication system;

(3) a transmission shift lever is not in park P;

(4) the maximum allowable discharge power of the power battery is below a lower limit of power;

or

(5) water temperature at an engine thermostat is less than a lower limit of a preset temperature.

4. A method of controlling a hybrid electric vehicle, the method comprising:

detecting that the hybrid electric vehicle'"'"'s electric power is on;

enabling, by a control module, the hybrid electric vehicle to enter into an operating mode through an engine power subsystem and a motor power subsystem in an instance;

detecting that the hybrid electric vehicle operates in a HEV-eco mode;

detecting that;

(1) a road slope is lower than or equal to a lower limit of slope, and an electric quantity of a power battery is lower than or equal to a lower limit of the electric quantity of the power battery of the motor power subsystem;

or

(2) the road slope is lower than or equal to the lower limit of slope, and a maximum allowable discharge power of the power battery is lower than or equal to a lower limit of the maximum allowable discharge power;

determining that the hybrid electric vehicle operates in a low power strategy;

detecting that a hybrid electric vehicle speed is zero; and

enabling, by the control module, the hybrid electric vehicle to operate by idle start-stop strategy.

5. The method according to claim 4, further comprising:

controlling an engine to shut off, by the control module, when the hybrid electric vehicle operates by idle start-stop strategy, the engine is running, and when all of following conditions is satisfied;

(1) no fault is detected in a high-pressure system;

(2) no fault is detected in a communication system;

(3) a transmission shift lever is in park P;

(4) the maximum allowable discharge power of the power battery of the motor power subsystem exceeds an upper limit of power; and

(5) water temperature at an engine thermostat is greater than an upper limit of a preset temperature.

6. The method according to claim 4, further comprising:

controlling an engine to turn on, by the control module, when the hybrid electric vehicle operates by idle start-stop strategy, the engine turns off, and when any of following conditions is satisfied;

(1) a fault has been detected in a high-pressure system;

(2) a fault has been detected in a communication system;

(3) a transmission shift lever is not in park P;

(4) the maximum allowable discharge power of the power battery of the motor power subsystem is below a lower limit of power;

or

(5) water temperature at engine thermostat is less than a lower limit of a preset temperature.