HYBRID VEHICLE CONTROL UNIT

• US 20150197238A1
• Filed: 01/13/2015
• Published: 07/16/2015
• Est. Priority Date: 01/14/2014
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: ITOH, Yutaro, IKEMOTO, Noriaki
• Granted Patent: US 9,162,671 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60K 2006/4825 Electric machine connected or connectable to gearbox input shaft
• CPC Class Codes: B60K 6/20 the prime-movers consisting of electric motors and internal combustion engines, e.g. HEVs
• CPC Class Codes: B60K 6/22 characterised by apparatus, components or means specially adapted for HEVs
• CPC Class Codes: B60K 6/26 characterised by the motors or the generators
• CPC Class Codes: B60K 6/28 characterised by the electric energy storing means, e.g. batteries or capacitors
• CPC Class Codes: B60K 6/32 characterised by the fuel cells
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 1/02 to electric heating circuits
• CPC Class Codes: B60L 15/2045 for optimising the use of energy
• CPC Class Codes: B60L 2210/00 Converter types
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2220/14 Synchronous machines
• CPC Class Codes: B60L 2240/34 Cabin temperature
• CPC Class Codes: B60L 2240/36 Temperature of vehicle components or parts
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2240/80 Time limits
• CPC Class Codes: B60L 3/12 Recording operating variables ; Monitoring of operating variables
• CPC Class Codes: B60L 50/16 : with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 50/40 : using propulsion power supplied by capacitors
• CPC Class Codes: B60L 58/12 : responding to state of charge [SoC]
• CPC Class Codes: B60L 58/20 : having different nominal voltages
• 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 20/13 : in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2510/244 : Charge state
• CPC Class Codes: B60W 2710/24 : Energy storage means
• CPC Class Codes: B60W 2710/244 : Charge state
• CPC Class Codes: B60W 2710/305 : target power to auxiliaries
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• 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
• CPC Class Codes: Y02T 90/40 : Application of hydrogen technology to transportation, e.g. using fuel cells
• CPC Class Codes: Y10S 903/907 : Electricity storage, e.g. battery, capacitor
• CPC Class Codes: Y10S 903/93 : Conjoint control of different elements

Abstract

A hybrid vehicle control unit (HV-ECU) sets a sub-battery voltage during an engine non-operation time to be lower than a sub-battery voltage during the normal time, which decreases a charge amount to the sub-battery relative to an amount during the normal time. The HV-ECU sets the sub-battery voltage during an engine operation time to be higher than the sub-battery voltage during the engine non-operation time, which increases the charge amount to the sub-battery relative to an amount during the engine non-operation time. An SOC control according to the above-described scheme prevents an SOC decrease of the sub-battery SOC in comparison to the conventional SOC control scheme, thereby preventing charging of the sub-battery when the main battery SOC is lower than a certain threshold. Therefore, a run-down of the sub-battery is prevented.

Claims

1. A hybrid vehicle drive system installed in a hybrid vehicle, the hybrid vehicle drive system comprising:

an engine;

a motor-generator generating electricity by a drive force of the engine;

a main battery chargeable and dischargeable in an exchange of electricity with the motor-generator;

a sub-battery electrically connected with the main battery;

a DC-DC converter disposed between the main battery and the sub-battery and converting an input voltage from the main battery to an output battery voltage that is output to the sub-battery which is designated as a sub-battery voltage; and

a hybrid vehicle control unit (HV-ECU) controlling the sub-battery voltage of the sub-battery, wherein

a normal time is defined as a time when a main battery SOC is equal to or higher than a preset threshold, and

when the main battery SOC is less than the preset threshold,

(i) in an engine non-operation time, the HV-ECU sets a sub-battery voltage during the engine non-operation time to be lower than a sub-battery voltage during the normal time to decrease sub-battery charging during the engine non-operation time relative to sub-battery charging during the normal time, and

(ii) in an engine operation time, the HV-ECU sets a sub-battery voltage during the engine operation time to be higher than the sub-battery voltage during the engine non-operation time to increase sub-battery charging during the engine operation time relative to sub-battery charging during the engine non-operation time.

2. The hybrid vehicle drive system of claim 1, wherein

the HV-ECU increases the sub-battery voltage as a drive load of the vehicle decreases to increase sub-battery charging.

3. The hybrid vehicle drive system of claim 2, wherein

the charge amount to the sub-battery is determined to minimize a system loss that is calculated as a sum of an engine loss and a sub-battery I/O loss caused by charge and discharge of the sub-battery.

4. The hybrid vehicle drive system of claim 1, further comprising:

an electric heater heating at least one of a vehicle compartment or the engine, the electric heater being controlled by the HV-ECU and electrically connected to a sub-battery side of the DC-DC converter, wherein

the HV-ECU sets an output of the electric heater during the engine non-operation time to be less than an output of the electric heater during the normal time, and

the HV-ECU sets an output of the electric heater during the engine operation time to be greater than the output of the electric heater during the engine non-operation time.

5. The hybrid vehicle drive system of claim 4, wherein

the HV-ECU increases the output of the electric heater as a drive load of the vehicle decreases, which increases an amount of electricity supplied from the DC-DC converter to the electric heater.

6. The hybrid vehicle drive system of claim 4, wherein

an amount of decrease of the output of the electric heater during the engine non-operation time is determined based on an integrated value of an amount of increase of the output of the electric heater during the engine operation time either during a period of time between a present time and a specific previous time and or during a past predetermined period of time.

7. The hybrid vehicle drive system of claim 1, wherein

the electricity supplied to the DC-DC converter in the engine operation time is procured entirely from the motor-generator.