On-vehicle battery condition estimation device

• US 20090295399A1
• Filed: 05/26/2009
• Published: 12/03/2009
• Est. Priority Date: 05/28/2008
• Status: Active Grant

• Current Assignee: DENSO Corporation, Nippon Soken, Inc.
• Original Assignee: DENSO Corporation, Nippon Soken, Inc.
• Inventors: Saito, Shigenori, Mizuno, Satoru, Ueda, Kenji
• Granted Patent: US 8,552,688 B2
• Time in Patent Office: Days
• US Class Current: 324/429
• CPC Class Codes: B60L 58/14 Preventing excessive discharging
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 30/192 Mitigating problems related to power-up or power-down of the driveline, e.g. start-up of a cold engine
• CPC Class Codes: F02D 41/042 for stopping the engine
• CPC Class Codes: F02N 11/0825 related to prevention of engine restart failure, e.g. disabling automatic stop at low battery state
• CPC Class Codes: F02N 2200/063 Battery voltage
• CPC Class Codes: F02N 2300/2006 using prediction of future conditions
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A battery condition estimation device estimates a pre-restart voltage drop amount ΔVjh+ΔVbn of a battery mounted to a vehicle during period T1 to T2 from initiation of an engine stop until initiation of an engine restart based on detection values regarding the battery condition. The device estimates a voltage drop amount ΔVst during period T3 from initiation of the engine restart until completion of the engine restart based on the detection values regarding the battery condition. The device finally estimates a minimum voltage of the battery during period T1 to T3 from the initiation of the engine stop until the completion of the engine restart based on a voltage detection value Vj0 before the engine stop, the pre-restart voltage drop amount ΔVjh+ΔVbn, and the voltage drop amount ΔVst.

Claims

1. A battery condition estimation device capable of estimating conditions of an on-vehicle battery mounted to a vehicle, which acts as an electric power supply source to supply an electric power to on-vehicle devices such as an engine starter to start an internal combustion engine, comprising:

pre-start operation voltage drop estimation means capable of estimating a battery voltage drop amount, as a pre-start operation voltage drop amount of the on-vehicle battery, based on at least one of detection values regarding battery condition, during a period from initiation of a stop operation of the internal combustion engine until initiation of a restart operation of the internal combustion engine;

start operation voltage drop estimation means capable of estimating a battery voltage drop amount, as a start operation voltage drop amount, based on at least one of the detection values regarding the battery condition, during a period from the initiation of the restart operation until completion of the restart operation of the internal combustion engine; and

minimum voltage estimation means capable of estimating a minimum voltage of the on-vehicle battery during a period from the initiation of the stop operation of the internal combustion engine until the completion of the restart operation of the internal combustion engine based on a voltage value of the on-vehicle battery detected before the initiation of the stop operation of the internal combustion engine, the pre-start voltage drop amount of the on-vehicle battery estimated by the pre-start operation voltage drop estimation means, and the start operation voltage drop amount estimated by the start operation voltage drop estimation means.

2. The battery condition estimation device according to claim 1, wherein the pre-start operation voltage drop estimation means comprises pre-stop operation voltage drop estimation means capable of estimating a battery voltage drop amount of the on-vehicle battery, as a pre-stop operation voltage drop amount, during a period from the initiation of the stop operation until the completion of the stop operation of the internal combustion engine based on at least one of the detection values regarding the battery condition.

3. The battery condition estimation device according to claim 1, wherein the pre-start operation voltage drop estimation means comprises post-stop operation voltage drop estimation means capable of estimating a battery voltage drop amount of the on-vehicle battery, as a post-stop operation voltage drop amount, during a period from the completion of the stop operation until the initiation of the restart operation of the internal combustion engine based on at least one of the detection values regarding the battery condition.

4. The battery condition estimation device according to claim 1, wherein the pre-start operation voltage drop estimation means comprises:

pre-stop operation voltage drop estimation means capable of estimating a battery voltage drop amount of the on-vehicle battery, as a pre-stop operation voltage drop amount, during a period from the initiation of the stop operation until the completion of the stop operation of the internal combustion engine based on at least one of the detection values regarding the battery condition; and

post-stop operation voltage drop estimation means capable of estimating a battery voltage drop amount of the on-vehicle battery, as a post-stop operation voltage drop amount, during a period from the completion of the stop operation until the initiation of the restart operation of the internal combustion engine based on at least one of the detection values regarding the battery condition.

5. The battery condition estimation device according to claim 2, further comprising an internal resistance value map which stores a relationship between a current value or a voltage value and an internal resistance value of the on-vehicle battery in a one to one correspondence,

wherein the pre-stop operation voltage drop estimation means estimates the pre-stop operation voltage drop amount based on the internal resistance value obtained from the internal resistance value map and a current change amount of the on-vehicle battery detected during the period from the initiation of the stop operation until the completion of the stop operation of the internal combustion engine.

6. The battery condition estimation device according to claim 5, wherein the internal resistance map has:

a current-internal resistance value map storing a relationship between a current value and an internal resistance value of the on-vehicle battery in a one to one correspondence; and

a voltage-internal resistance value map storing a relationship between a voltage value and an internal resistance value of the on-vehicle battery in a one to one correspondence,

wherein when the output voltage of an AC generator capable of charging the on-vehicle battery is equal to an adjustment voltage, the pre-stop operation voltage drop estimation means estimates the pre-stop operation voltage drop amount of the on-vehicle battery based on the current change amount of the on-vehicle battery detected during the period from the initiation of the stop operation until the completion of the stop operation of the internal combustion engine, and based on the internal resistance value of the on-vehicle battery obtained from the current-internal resistance value map based on the current value of the on-vehicle battery detected before the initiation of the stop operation of the internal combustion engine, and

when the output voltage of the AC generator capable of charging the on-vehicle battery is less than the adjustment voltage, the pre-stop operation voltage drop estimation means estimates the pre-stop operation voltage drop amount of the on-vehicle battery based on the current change amount of the on-vehicle battery detected during the period from the initiation of the stop operation until the completion of the stop operation of the internal combustion engine, and based on the internal resistance value of the on-vehicle battery obtained from the voltage-internal resistance value map based on the voltage value of the on-vehicle battery detected before the initiation of the stop operation of the internal combustion engine.

7. The battery condition estimation device according to claim 2, wherein the pre-stop operation voltage drop estimation means obtains the current value and the internal resistance value which are detected during after the initiation of a previous stop operation until the completion of the previous stop operation of the internal combustion engine, sets a value as a current internal resistance value of the on-vehicle battery, where the value is obtained by multiplying the internal resistance value previously detected and a coefficient corresponding to a ratio between the current value currently detected and the current value previously detected of the on-vehicle battery, and

the pre-stop operation voltage drop estimation means estimates the pre-stop operation voltage drop amount based on the current change amount of the on-vehicle battery and the internal resistance value currently detected.

8. The battery condition estimation device according to claim 3, further comprising a post-stop operation voltage drop estimation map storing at least one of the information regarding the battery condition and a pre-stop operation voltage drop amount in a one to one correspondence, and

wherein the post-stop operation voltage drop estimation means estimates the post-stop operation voltage drop amount of the on-vehicle battery based on at least one of the information regarding the battery condition and the post-stop operation voltage drop estimation map.

9. The battery condition estimation device according to claim 1, wherein the start operation voltage drop estimation means obtains a maximum changed amount of current based on the current value and the internal resistance value which are detected during the period from the initiation of the restart operation until the completion of the restart operation of the internal combustion engine, and the start operation voltage drop estimation means estimates a start operation voltage drop amount of the on-vehicle battery based on the internal resistance value and the maximum changed amount of current of the on-vehicle battery.

10. The battery condition estimation device according to claim 1, further comprising a capacitance-internal resistance value map which stores a relationship between a capacitance of the on-vehicle battery and the internal resistance value of the on-vehicle battery in a one to one correspondence,

wherein the start operation voltage drop estimation means obtains the maximum changed amount of current based on the current value detected during the period from the initiation of a previous restart operation until the completion of the previous restart operation of the internal combustion engine, obtains the internal resistance value of the on-vehicle battery based on the capacitance of the on-vehicle battery and the capacitance-internal resistance value map, and estimates the start operation voltage drop amount of the on-vehicle battery based on the maximum changed amount of current and the internal resistance value of the on-vehicle battery.

11. The battery condition estimation device according to claim 10, further comprising map update means capable of collecting information regarding the battery condition when the current value of the on-vehicle battery regarding the maximum changed amount of current is detected according to the capacitance and temperature of the on-vehicle battery and capable of updating the capacitance-internal resistance value map based on the information regarding the battery condition.

12. The battery condition estimation device according to claim 1, wherein the minimum voltage estimation means estimates the minimum voltage of the on-vehicle battery during the period from the initiation of the stop operation until the completion of the restart operation of the internal combustion engine by subtracting the pre-start operation voltage drop amount and the start operation voltage drop amount from the voltage value detected before the initiation of the stop operation of the internal combustion engine.