Method and arrangement for determining the starting ability of a starter battery of an internal combustion engine

• US 20020082765A1
• Filed: 11/19/2001
• Published: 06/27/2002
• Est. Priority Date: 11/17/2000
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Schoch, Eberhard
• Granted Patent: US 6,732,043 B2
• Time in Patent Office: Days
• US Class Current: 701/113
• CPC Class Codes: F02N 11/0862 characterised by the electrical power supply means, e.g. battery
• CPC Class Codes: F02N 2200/063 Battery voltage
• CPC Class Codes: F02N 2200/064 Battery temperature
• CPC Class Codes: G01R 31/3647 for determining the ability of a battery to perform a critical function, e.g. cranking

Abstract

A method of determining the starting ability of a starter battery of an internal combustion engine, according to which a charge status of the starter battery is determined, which has an influence on starting ability. Also determined is a temperature which has an influence on starting ability, in particular the temperature of the starter battery. Moreover, an average voltage drop of the starter battery during a starting phase is calculated or determined, in particular during a turn-over phase of a starter motor, which is in an operative connection with the starter battery. The starting ability of the starter battery is estimated by comparing the calculated or determined average voltage drop with a threshold value.

Claims

1. A method of determining a starting ability of a starter battery of an internal combustion engine, comprising the steps of:

determining a charge status of the starter battery, the charge status having an influence on the starting ability;

determining a temperature that has an influence on the starting ability;

one of calculating and determining an average voltage drop of the starter battery during a starting phase of a starter motor that is in an operative connection with the starter battery; and

estimating the starting ability of the starter battery by comparing the one of calculated and determined average voltage drop with a threshold value.

2. The method according to claim 1, wherein:

the temperature corresponds to a temperature of the starter battery.

3. The method according to claim 1, wherein:

the starting phase is a turn-over phase of the starter motor.

4. The method according to claim 1, wherein:

the one of calculated and determined average voltage drop is compared with the threshold value in accordance with an equation of the form

U₀(soc, T_Batt)Δ

U_{Batt, mitt}(soc, T_Batt)=U_{Batt, min}

and

soc is the charge status, T_Batt is the temperature corresponding to a temperature of the starter battery, U₀ is an open-circuit voltage of the starter battery, Δ

U_{Batt, mitt} is the one of calculated and determined average voltage drop, and U_{Batt, min} is the threshold value corresponding to a minimum voltage of the starter battery that can be used to achieve a starter rpm.

5. The method according to claim 4, wherein:

the one of calculated and determined average voltage drop is calculated according to an equation of the form

Δ

U_{Batt, mitt}(soc, T_Batt)=1/n*/Σ

(U₀(soc, T_Batt)−

U_{Batt, 1})

at times i=1 . . . n.

6. The method according to claim 4, wherein:

the open-circuit voltage of the starter battery is determined on the basis of an equation of the form (U₀(soc, T_Batt)=6*(1.88+0,247*soc+(T_BATT−

25)*0.23e-3).

7. The method according to claim 2, further comprising the step of:

determining and storing an engine characteristics map of the one of calculated and determined average voltage drop as a function of the temperature of the starter battery and the charge status on the basis of values thus obtained for the one of calculated and determined average voltage drop.

8. An arrangement for determining a starting ability of a starter battery of an internal combustion engine, comprising:

an element for determining a charge status of the starter battery, the charge status having an influence on the starting ability;

an element for determining a temperature that has an influence on the starting ability;

an element for one of calculating and determining an average voltage drop of the starter battery during a starting phase of a starter motor that is in an operative connection with the starter battery; and

an element for estimating the starting ability of the starter battery by comparing the one of calculated and determined average voltage drop with a threshold value.

9. The arrangement according to claim 8, wherein:

the temperature corresponds to a temperature of the starter battery.

10. The arrangement according to claim 8, wherein:

the starting phase is a turn-over phase of the starter motor.