Method for managing an alternator combined with at least one power battery and driven by a heat engine

Patent metadata

Field	Value
Publication number	US-9682629-B2
Application number	US-201214362786-A
Country	US
Kind code	B2
Filing date	Nov 22, 2012
Priority date	Dec 6, 2011
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

A method for managing a motor vehicle including a first battery connected to an alternator and an electrical network, the alternator operable either at a positive low alternator voltage or a high alternator voltage higher than the low alternator voltage, the method including: estimating a potential recharging current strength that the first battery could absorb if it was, at that moment, powered by the high alternator voltage; estimating a first alternator yield corresponding to a current rotation speed of the alternator, and to a strength of consumed current actually fed into the network; estimating a second alternator yield corresponding to the current rotation speed of the alternator and to the sum of strengths of a potential recharging current of the battery and of the consumed current; and imposing a high alternator voltage if the difference between the first yield and the second yield is higher than a first threshold.

First claim

The invention claimed is:

1. An electric power supply system for a vehicle including a heat engine able to propel the vehicle, comprising:
a network of at least one electricity consuming member;
a first electric accumulator battery connected to the network;
a controllable alternator connected to the network, driven by the engine, and configured to deliver electric power to the network at a setpoint voltage controllable to at least a strictly positive low alternator voltage, and to a high alternator voltage strictly higher than the low alternator voltage;
an ammeter configured to measure instantaneous intensity consumed by the network;
an estimator of a state of charge of the first battery configured to estimate intensity of a potential recharging current that the first battery would be capable of absorbing if the first battery was at that instant powered at the high alternator voltage;
a meter of a speed of rotation of the alternator;
an electronic control unit linked to the meter, to the state of charge estimator, and to the ammeter, and linked to a map of the alternator yield as a function of alternator speed and of intensity output by the alternator, the electronic control unit configured to estimate a first alternator yield corresponding to a current speed of rotation of the alternator, and to an intensity of current consumed actually drawn from the network, to estimate a second alternator yield corresponding to the current speed of rotation of the alternator and to the sum of intensities of a potential recharging current of the battery and of the current consumed, and to impose the high alternator voltage if the difference between the second alternator yield and the first alternator yield is higher than a first threshold.

2. The system as claimed in claim 1 , wherein the electronic control unit is configured to stop imposing a high alternator voltage if the difference between the second yield and the first yield again becomes lower than a second threshold lower than or equal to the first threshold.

3. The system as claimed in claim 1 , wherein the electronic control unit is configured to impose a low alternator voltage if the state of charge of the first battery becomes higher than a third threshold or if the potential recharging current becomes lower than a fourth threshold.

4. The system as claimed in claim 1 , wherein the electronic control unit is linked to an estimator of the engine yield, and is configured to impose the high alternator voltage only if the product of the engine yield and the second yield is higher than a fifth threshold.

5. The power supply system as claimed in claim 1 , further comprising a second electric accumulator battery connected to the alternator and configured to power a starter configured to launch the vehicle engine, the second battery having a second maximum no-load voltage that is lower than a first maximum no-load voltage of the first battery, and which is lower than the low alternator voltage.

6. The system as claimed in claim 5 , further comprising a driving monitoring unit linked to the alternator, configured to detect types of driving of the vehicle, and configured to impose the high alternator voltage during at least certain phases of driving of the vehicle including phases of regenerative braking, and to impose the low alternator voltage during other phases of driving that consume more fuel than the certain driving phases, unless the electronic control unit imposes the high alternator voltage.

7. The system as claimed in claim 6 , further comprising a regulator configured to vary a drive ratio between the speed of rotation of the alternator and a speed of rotation of the engine, the driving monitoring unit being linked to the regulator and configured to impose at least a first drive ratio if it detects driving of city type, and to impose at least a second drive ratio lower than the previous one, if it detects driving of highway type.

8. The system as claimed in claim 1 , further comprising a regulator configured to vary a drive ratio between the speed of rotation of the alternator and a speed of rotation of the engine, the electronic control unit being linked to the regulator and configured to compute a first alternator yield and a second alternator yield corresponding to the current speed of the alternator, and a first and a second alternator yield corresponding to a different drive ratio from the current ratio, and is configured so that, if the difference between the second alternator yield and the first alternator yield is higher than the first threshold for at least one of the two drive ratios, the control unit imposes the drive ratio making it possible to obtain the highest second alternator yield.

9. A method for managing a motor vehicle including a first battery connected to an alternator and to a power network of the vehicle,
the alternator being controllable to operate either at a strictly positive low alternator voltage, or at least at a high alternator voltage strictly higher than the low alternator voltage, the method comprising:
estimating an intensity of a potential recharging current that the first battery would be capable of absorbing if the first battery was at that instant powered at the high alternator voltage;
estimating a first alternator yield corresponding to a current speed of rotation of the alternator, and to an intensity of effectively consumed current output in the network;
estimating a second alternator yield corresponding to the current speed of rotation of the alternator and to the sum of intensities of the potential recharging current of the battery and of the current consumed; and
imposing a high alternator voltage if the difference between the second yield and the first yield is higher than a first threshold.

10. The management method as claimed in claim 9 , wherein the drive ratio is varied between the speed of rotation of the alternator and the speed of rotation of an engine driving the alternator, so as to increase the difference between the second yield and the first yield, for at least a range of speeds of rotation of the engine.

Assignees

• Renault Sas

Inventors

• Saint-Leger Gerard
• Demure Sophie

Classifications

• Y02T10/70

  Energy storage systems for electromobility, e.g. batteries · CPC title

• Y02T10/92

  Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles · CPC title

• B60L1/003 Primary

  to auxiliary motors, e.g. for pumps, compressors · CPC title

• H02J7/163

  with special means for initiating or limiting the excitation current · CPC title

• B60L2240/421

  Speed · CPC title