Power supply control apparatus and method for hybrid vehicle

• US 8,039,976 B2
• Filed: 07/11/2007
• Issued: 10/18/2011
• Est. Priority Date: 09/20/2006
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toyota Jidoshokki, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Kabushiki Kaisha Toyota Jidoshokki, Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Takeuchi, Junichi, Oki, Ryoji, Sato, Eiji
• Primary Examiner(s): NGUYEN, HANH N
• Application Number:
  US12/310,128
• Publication Number:
  US 20100001523A1
• Time in Patent Office: 1,560 Days
• Field of Search: 290/40.A, 290/40.B, 290/40.C, 290/40.F, 290/40.R, 180/65.21, 180/65.225, 180/65.23
• US Class Current: 290/40.00C
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• CPC Class Codes: B60K 6/28 characterised by the electric energy storing means, e.g. batteries or capacitors
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/445 Temperature
• CPC Class Codes: B60L 2270/20 Inrush current reduction, i.e. avoiding high currents when connecting the battery
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: B60L 58/24 for controlling the temperature of batteries
• CPC Class Codes: B60L 58/25 by controlling the electric load
• 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 10/24 including control of energy storage means
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 10/30 including control of auxiliary equipment, e.g. air-conditioning compressors or oil pumps
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• 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 2510/0676 : Engine temperature
• CPC Class Codes: B60W 2510/244 : Charge state
• CPC Class Codes: B60W 2510/246 : Temperature
• CPC Class Codes: B60W 30/194 : related to low temperature conditions, e.g. high viscosity of hydraulic fluid
• CPC Class Codes: B60Y 2400/112 : Batteries
• CPC Class Codes: F02D 2200/503 : Battery correction, i.e. corrections as a function of the state of the battery, its output or its type
• CPC Class Codes: F02D 29/02 : peculiar to engines driving vehicles; peculiar to engines driving variable pitch propellers
• CPC Class Codes: F02D 29/06 : peculiar to engines driving electric generators
• CPC Class Codes: F02N 11/04 : the motors being associated with current generators
• CPC Class Codes: F02N 11/0848 : with means for detecting successful engine start, e.g. to stop starter actuation
• CPC Class Codes: F02N 11/0866 : comprising several power sources, e.g. battery and capacitor or two batteries
• CPC Class Codes: F02N 2011/0888 : DC/DC converters
• CPC Class Codes: F02N 2011/0896 : Inverters for electric machines, e.g. starter-generators
• CPC Class Codes: F02N 2200/023 : Engine temperature
• CPC Class Codes: F02N 2200/046 : Energy or power necessary for starting
• CPC Class Codes: F02N 2200/064 : Battery temperature
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

When the temperature of an engine and a main battery is low at the time of activating a vehicle system, an ECU starts the engine in advance and outputs a running permission signal after completion of engine startup. At this stage, the ECU suspends a defect diagnosis operation on a subsidiary load and feedback-controls the DC/DC converter by setting the voltage control value to a level lower than the output voltage from the subsidiary battery and at least the lower limit of the operating voltage of the ECU. The ECU feedback-controls the DC/DC converter by setting the voltage control value to a level of at least the output voltage of the subsidiary battery in response to completion of engine start-up. Then, the suspension of the defect diagnosis operation on the subsidiary load is canceled and a running permission signal is output.

Claims

1. A power supply control apparatus for a hybrid vehicle, comprising:

a first power supply providing a first power supply voltage,

a motor receiving supply of power from said first power supply to start an internal combustion engine,

a voltage converter connected parallel to said motor with respect to said first power supply to voltage-convert said first power supply voltage according to a voltage control value for output between first and second power supply lines,

a second power supply connected between said first and second power supply lines, providing a second power supply voltage that is lower than said first power supply voltage,

an electric load connected between said first and second power supply lines to receive voltage from at least one of said voltage converter and said second power supply,

a control device receiving voltage from the at least one of said voltage converter and said second power supply to control startup of said internal combustion engine and said voltage converter according to designation of activation of a vehicle system, and

a defect diagnosis device giving a diagnosis of a defect at said electric load based on a voltage output between said first and second power supply lines becoming lower than a lower limit of an operating voltage at which a proper operation of said electric load is ensured,

wherein said control device comprises

a first voltage conversion control unit that controls said voltage converter by setting said voltage control value to a first voltage that is lower than said second power supply voltage and that is at least the lower limit of an operating voltage of said control device,

a defect diagnosis prohibition unit that prohibits a defect diagnosis operation of said defect diagnosis device in response to said voltage control value set to said first voltage,

a low temperature startup control unit that drive-controls said motor to start said internal combustion engine in response to a temperature of at least one of said internal combustion engine and said first power supply being not more than a predetermined threshold value,

a second voltage conversion control unit that controls said voltage converter by setting said voltage control value to a second voltage that is at least said second power supply voltage in response to completion of the startup of said internal combustion engine, and

a running permission unit that cancels the prohibition of the defect diagnosis operation of said defect diagnosis device and designating a running permission of said hybrid vehicle in response to said voltage control value being set at said second voltage.

2. The power supply control apparatus for a hybrid vehicle according to claim 1, wherein said control device further comprises

output power estimation unit that estimates power that can be output by said first power supply based on a temperature and a state of charge of said first power supply,

said first voltage conversion control unit sets said voltage control value to said first voltage when said estimated power that can be output from said first power supply becomes lower than a predetermined power required for the startup of said internal combustion engine, and

sets said voltage control value to said second voltage control value to said second voltage when said estimated power that can be output from said first power supply is at least said predetermined power.

3. The power supply control apparatus for a hybrid vehicle according to claim 2,

wherein said first voltage conversion control unit further comprises a required power estimation unit that estimates predetermined power required for the startup of said internal combustion engine,

said required power estimation unit estimates supply power to said motor based on a temperature of said internal combustion engine, and calculates said predetermined power by adding power consumption of said control device estimated in advance and charging power of said second power supply to said estimated supply power to said motor.

4. The power supply control apparatus for a hybrid vehicle according to claim 3, wherein said first voltage conversion control unit feedback-controls said voltage converter such that an output voltage matches said voltage control value.

5. The power supply control apparatus for a hybrid vehicle according to claim 2, wherein said first voltage conversion control unit feedback-controls said voltage converter such that an output voltage matches said voltage control value.

6. The power supply control apparatus for a hybrid vehicle according to claim 1, wherein said first voltage conversion control unit feedback-controls said voltage converter such that an output voltage matches said voltage control value.

7. A power supply control method for a hybrid vehicle, said hybrid vehicle including

a first power supply providing a first power supply voltage,

a motor receiving supply of power from said first power supply to start an internal combustion engine,

a voltage converter connected parallel to said motor with respect to said first power supply to voltage-convert said first power supply voltage according to a voltage control value for output between first and second power supply lines,

a second power supply connected between said first and second power supply lines, providing a second power supply voltage that is lower than said first power supply voltage,

an electric load connected between said first and second power supply lines to receive voltage from at least one of said voltage converter and said second power supply,

a control device receiving voltage from at least one of said voltage converter and said second power supply to control startup of said internal combustion engine and said voltage converter according to designation of activation of a vehicle system, and

a defect diagnosis device giving a diagnosis of a defect at said electric load based on a voltage output between said first and second power supply lines becoming lower than a lower limit of an operating voltage at which a proper operation of said electric load is ensured,

said power supply control method comprising:

a first step of setting said voltage control value to a first voltage that is lower than said second power supply voltage and that is at least a lower limit of an operating voltage of said control device in response to a temperature of at least one of said internal combustion engine and said first power supply being not more than a predetermined threshold value,

a second step of prohibiting a defect diagnosis operation of said defect diagnosis device in response to said voltage control value being set to said first voltage,

a third step of feedback-controlling said voltage converter such that an output voltage matches said voltage control value, and drive-controlling said motor to start said internal combustion engine,

a fourth step of feedback-controlling said voltage converter by setting said voltage control value to a second voltage that is at least said second power supply voltage in response to completion of the startup of said internal combustion engine, and

a fifth step of canceling the prohibition of a defect diagnosis operation of said defect diagnosis device, and designating a running permission of said hybrid vehicle in response to said voltage control value being set to said second voltage.

8. The power supply control method for a hybrid vehicle according to claim 7, wherein said first step comprises

a first substep of estimating power that can be output by said first power supply based on a temperature and a state of charge of said first power supply,

a second substep of setting said voltage control value to said first voltage when said estimated power that can be output by said first power supply becomes lower than a predetermined power required for the startup of said internal combustion engine, and

a third substep of setting said voltage control value to said second voltage when said estimated power that can be output by said first power supply is at least said predetermined power.