U.S. patent application number 10/248806 was filed with the patent office on 2004-08-26 for method and apparatus for charging a battery of an automotive vehicle having dual voltage electrical systems.
This patent application is currently assigned to FORD GLOBAL TECHNOLOGIES, INC.. Invention is credited to Berels, David Jeffeory.
Application Number | 20040164703 10/248806 |
Document ID | / |
Family ID | 32867794 |
Filed Date | 2004-08-26 |
United States Patent
Application |
20040164703 |
Kind Code |
A1 |
Berels, David Jeffeory |
August 26, 2004 |
METHOD AND APPARATUS FOR CHARGING A BATTERY OF AN AUTOMOTIVE
VEHICLE HAVING DUAL VOLTAGE ELECTRICAL SYSTEMS
Abstract
An electrical system for an automotive vehicle includes a low
voltage battery having a low voltage, a high voltage battery having
a high voltage, and a DC-to-DC converter coupled to the low voltage
battery and the high voltage battery. A controller controls a
conversion of the low voltage to a high voltage through the
DC-to-DC converter and controls the charging of the high voltage
battery with the high voltage. The controller monitors a state of
charge of the high voltage battery, compares the state of charge to
a predetermined state of charge and generates an indicator when the
state of charge reaches the predetermined state of charge.
Inventors: |
Berels, David Jeffeory;
(Plymouth, MI) |
Correspondence
Address: |
KEVIN G. MIERZWA
ARTZ & ARTZ, P.C.
28333 TELEGRAPH ROAD, SUITE 250
SOUTHFIELD
MI
48034
US
|
Assignee: |
FORD GLOBAL TECHNOLOGIES,
INC.
Dearborn
MI
48126
|
Family ID: |
32867794 |
Appl. No.: |
10/248806 |
Filed: |
February 20, 2003 |
Current U.S.
Class: |
320/103 |
Current CPC
Class: |
B60L 58/12 20190201;
B60L 50/16 20190201; H02J 1/082 20200101; H02J 7/1423 20130101;
B60L 58/20 20190201; Y02T 10/70 20130101; B60L 2210/10 20130101;
Y02T 10/72 20130101; B60L 2210/40 20130101; Y02T 10/7072
20130101 |
Class at
Publication: |
320/103 |
International
Class: |
H02J 007/00 |
Claims
1. A method of charging a high voltage battery comprising:
electrically coupling a first low voltage source to a low voltage
battery; converting the low voltage to a high voltage; charging a
high voltage battery with the high voltage; monitoring a state of
charge of the high voltage battery; comparing the state of charge
to a predetermined state of charge; and generating an indicator
when the state of charge reaches the predetermined state of
charge.
2. A method as recited in claim 1 wherein when monitoring a state
of charge comprises measuring a battery voltage and measuring a
battery current.
3. A method as recited in claim 1 further comprising coupling the
low voltage battery to a high voltage battery through a
contactor.
4. A method as recited in claim 3 further comprising comparing the
low voltage battery voltage and the high voltage battery voltage
and controlling the contactor in response to comparing.
5. A method as recited in claim 1 wherein converting comprises
converting the low voltage to a high voltage using a DC-to-DC
converter.
6. A method as recited in claim 1 wherein said predetermined state
of charge corresponds to a starting state of charge to enable
starting of the engine with a starter/generator.
7. A method as recited in claim 1 wherein generating an indicator
comprises generating a visual indicator.
8. A method as recited in claim 1 wherein generating an indicator
comprises generating an audible indicator.
9. A method as recited in claim 1 further comprising generating an
initiating electrical signal from a switch coupled to a battery
terminal.
10. A method as recited in claim 1 wherein the indicator indicates
the high voltage battery is charged.
11. A method as recited in claim 1 further comprising generating a
second indicator indicating the high voltage battery is not charged
when the state of charge is less than the predetermined
threshold.
12. A method of charging a high voltage battery through a first low
voltage battery generating a low voltage with a low voltage source
electrically coupled to the low voltage battery comprising:
converting the low voltage to a high voltage through a DC-to-DC
converter; charging a high voltage battery with the high voltage;
monitoring a state of charge of the battery; comparing the state of
charge to a predetermined state of charge; generating a first
indicator when the state of charge is below the predetermined state
of charge; and generating a second indicator when the state of
charge reaches the predetermined state of charge.
13. A method as recited in claim 12 wherein when monitoring a state
of charge comprises measuring a battery voltage and measuring a
battery current.
14. A method as recited in claim 12 further comprising coupling the
low voltage battery to a high voltage battery through a
contactor.
15. A method as recited in claim 14 further comprising comparing
the first battery voltage and the second battery voltage and
controlling the contactor in response to comparing.
16. A system for an automotive vehicle comprising: a low voltage
battery having a low voltage; a high voltage battery having a high
voltage; a DC-to-DC converter coupled between the low voltage
battery and the high voltage battery; and a controller coupled to
the high voltage battery, the low voltage battery and said
controller controlling a conversion of the low voltage to a high
voltage through the DC-to-DC converter and controlling charging of
the high voltage battery with the high voltage, said controller
monitoring a state of charge of the high voltage battery, comparing
the state of charge to a predetermined state of charge, said
controller generating an indicator when the state of charge reaches
the predetermined state of charge.
17. A system as recited in claim 18 further comprising a
starter/generator and a starting load, wherein said predetermined
state of charge being a function of said temperature and said
starting load.
18. A system as recited in claim 18 further comprising a battery
terminal cover coupled to a battery terminal of the low voltage
battery.
19. A system as recited in claim 18 further comprising a cover
generating an electrical signal when the battery terminal cover is
in an open position, said electrical signal coupled to said
controller.
20. A hybrid electric vehicle having a system as recited in claim
18.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to dual voltage
automotive vehicles, and more specifically, to charging the
batteries of the electrical systems of the vehicle.
[0002] Automotive vehicles with internal combustion engines are
typically provided with both a starter motor and alternator. In
recent years, a combined alternator and starter motor has been
proposed. Such systems have a rotor mounted directly to the
crankshaft of the engine and a stator sandwiched between the engine
block and the bell housing of the transmission. During initial
startup of the vehicle, the starter/generator functions as a
starter. While functioning as a starter, the starter/generator
rotates the crankshaft of the engine while the cylinders are
fired.
[0003] After the engine is started, the starter/generator is used
as a generator to charge the electrical system of the vehicle.
[0004] Such systems may include both a 12-volt nominal system and a
36-volt nominal system, which correspond to 14 and 42-volt
operating voltages, respectively. It should be noted the dual
voltage systems may also be incorporated in vehicles without
starter/generators.
[0005] Electrical energy from the 42-volt battery of the vehicle is
used to turn the starter/generator, which in turn is used to start
the motor. Energy from the 12-volt system may be used to operate
the vehicle lights and instrument panel. Consequently, it is
important to maintain the battery so that a certain state of charge
is provided to allow the battery to provide enough power to the
starter/generator to start the engine. If one or both of the
batteries is low, however, the vehicle may need to be jumpstarted.
Typical jumpstarting is desirable, wherein jumper cables are
connected between a good battery or power source and the discharged
battery. Typically, if the 42-volt battery is low it may not be
charged by charging the 12-volt battery. It may not be desirable to
allow the operator to charge both batteries independently to
prevent mixing the voltage potentials and possibly damaging the
batteries or the electrical systems.
[0006] It would therefore be desirable to provide a method and
apparatus for charging a battery to provide an indication to the
vehicle operator to guide the operator through the charging
process.
SUMMARY OF INVENTION
[0007] The present invention provides a way in which to charge the
vehicle batteries so that both batteries of both voltage levels
become charged.
[0008] In one aspect of the invention, a method of charging a high
voltage battery includes electrically coupling a first low voltage
source to a low voltage battery, converting the low voltage to a
high voltage, charging a high voltage battery with the high
voltage, monitoring a state of-charge of the high voltage battery,
comparing the state of charge to a predetermined state of charge,
and generating an indicator when the state of charge reaches the
predetermined state of charge.
[0009] In a further aspect of the invention, a system for an
automotive vehicle includes a low voltage battery having a low
voltage, a high voltage battery having a high voltage, and a
DC-to-DC converter coupled to the low voltage battery and the high
voltage battery. A controller controls a conversion of the low
voltage to a high voltage through the DC-to-DC converter and
controls the charging of the high voltage battery with the high
voltage. The controller monitors a state of charge of the high
voltage battery, compares the state of charge to a predetermined
state of charge, and generates an indicator when the state of
charge reaches the predetermined state of charge.
[0010] One advantage is that the indicator may provide to the
vehicle operator both instructions and the state of charge of both
vehicle batteries.
[0011] Other advantages and features of the present invention will
become apparent when viewed in light of the detailed description of
the preferred embodiment when taken in conjunction with the
attached drawings and appended claims.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is a schematic view of an automotive vehicle having a
starter/generator system according to the present invention.
[0013] FIG. 2 is a flowchart illustrating the operation of the
present invention for charging the 12-volt battery.
[0014] FIG. 3 is a flowchart illustrating the operation of the
present invention for charging the 42-volt battery.
[0015] FIG. 4 is a side view of a battery terminal cover switching
apparatus according to one embodiment of the present invention.
DETAILED DESCRIPTION
[0016] The present invention is described with respect to a
particular configuration of a starter/generator relative to a
hybrid electric vehicle. However, the teachings of the present
invention may be applied to various type of vehicles having dual
battery powered electrical systems.
[0017] Referring now to FIG. 1, an automotive vehicle 10 is
illustrated having an internal combustion engine 12 having
cylinders 14 with pistons 16 located therein. Each cylinder 14 is
coupled to a fuel pump 18 through a fuel injector (not shown) or
other fuel delivery system. Each cylinder 14 also has a spark plug
20 or other ignition source coupled to a powertrain control unit. A
powertrain control unit 22 controls the ignition timing and fuel
pump 18 operating in a conventional manner subject to the
improvements of the present invention.
[0018] Engine 12 is coupled to a transmission 26. Transmission 26
may be automatic, manual or continuously variable. Transmission 26
is coupled to a differential 28 to drive an axle 30 to provide
power to wheels 32. Of course, the present invention is also
applicable to four-wheel drive systems in which all of the wheels
32 are driven.
[0019] A starter/generator system 40 that includes a
starter/generator 42 and its associated control electronics is
coupled to engine 12. In the present invention, starter/generator
42 is positioned between a housing 44 of transmission 26 and the
engine 12. Of course, those skilled in the art will recognize other
positions are available including, but not limited to, belt driven
types. Starter/generator 42 has a stator 46 fixedly attached to
bell housing 44 and a rotor 48 coupled to a crankshaft 50 of engine
12. A clutch 52 is used to engage and disengage engine 12 from
transmission 26. Starter/generator 42 is used as a starter during
engine startup and as an alternator to supply power to recharge the
batteries of the vehicle and to supply electrical loads. Clutch 52
allows starter/generator 42 to start the engine prior to engagement
of the transmission.
[0020] A vehicle system controller 54 is coupled to
starter/generator system 40. Vehicle system controller 54 is
coupled to powertrain control unit 22, to a power inverter 56 and a
battery control module 57. Collectively, controller 54 and battery
control module 57 may be referred to as a controller. In practice,
the power inverter 56, system controller 54 and battery control
module 57 may be contained in a single package or interconnected
using a bus system, thus making it unimportant which signals are
generated at which device. The inverter 56 is used to convert DC
power to AC power in the motoring mode and AC power to DC power in
power generation mode as will be further described below.
[0021] Battery controller 57 is coupled to 42-volt battery 64 to
monitor the voltage 76 and a current. By monitoring the battery
voltage and current, the state of charge of the 42-volt battery 64
may be determined.
[0022] Power inverter 56 is coupled to an energy storage device 58
such as an ultra capacitor, a first DC-to-DC converter 60, and a
second DC-to-DC converter 62. DC-to-DC converter 60 is coupled to a
nominal 36-volt battery 64. DC-to-DC converter 62 is coupled to a
nominal 12-volt battery 66. Of course, the actual battery voltage
is dependent on the particular system to which it is attached. The
present invention is particularly useful when one battery voltage
is much greater than the other battery voltage.
[0023] It should also be noted that a contactor 68 may be
electrically coupled between 36-volt battery 64 and DC-to-DC
converter 60 to provide electrical isolation between the 36-volt
battery and the rest of the vehicle. Battery control module 57 is
coupled to contactor 68 to control the opening and closing of
contactor 68.
[0024] System controller 54 is also coupled to an indicator 80.
Indicator 80 may comprise an audible indicator, a visual indicator,
or a combination of the two. One example of an indicator is an LCD
display that can display various messages and actions for the
vehicle operator to perform. Instrument panel reminder lights or
chimes may also be used to generate messages.
[0025] A 12-volt source 65 such as a 12-volt battery from another
vehicle, battery charger or generator is shown electrically coupled
to 12-volt battery 66.
[0026] Referring now to FIG. 2, a method for charging a 12-volt
battery when the 42-volt battery is charged is illustrated. In step
100 if the 12-volt battery is not dead and the 42-volt battery is
not charged the system starts again in step 100. In step 100 if the
12-volt battery is not charged and the 42-volt battery is charged,
step 102 is executed. In step 102, the 12-volt battery is charged
in a conventional manner. That is, jumper cables may be connected
from a 12-volt source such as another charged battery. Typically,
when charging a 12-volt battery the positive terminal of the
charged battery is connected to the positive terminal of the dead
battery, while the negative terminal of the charged battery is
coupled to chassis ground in the vehicle with the dead battery. The
negative battery terminals may also be coupled together. In step
104 the charge of the 12-volt battery is monitored during the
charging process. In step 106 a message indicating that the 12-volt
battery charging is complete may be displayed to the driver. The
message may take the form of one of the indicators described above
such as audible, an indicator light, or an LCD message.
[0027] Referring now to FIG. 3, a method for charging the 42-volt
battery whether or not the 12-volt battery is discharged is
illustrated. In the case where a 12-volt battery is discharged, the
12-volt battery may be charged simultaneously with the 42-volt
battery. In step 110, if the 42-volt battery is not dead the system
continues checking in step 110. In step 110, if the 42-volt battery
is dead step 112 is executed. In step 112 a switch may be activated
as will be further described below. If the switch is activated, the
jumpstart process has been entered. This step is performed
simultaneously with step 114. In step 114 the jumper cables are
connected to the 12-volt battery in the manner described above.
During the process, messages or other indicators may be
illuminated. In step 116 if the 12-volt battery voltage is greater
than the voltage of the 42-voltage battery an error message is
generated in step 118. In step 116 if the 12-volt battery voltage
is not greater than the 42-volt battery step 120 is executed. In
step 120 the contactor 68 described above is closed. The DC-to-DC
converter 60 is then used to convert the 12-volt power to 42-volt
power so that 36-volt battery 64 may be charged in step 122. In
step 124 the state of charge of the 36-volt battery is monitored.
In step 126, a display message may be displayed to the vehicle
operator to continue charging until otherwise notified. In step 128
the state of charge of the 42-volt battery is monitored. If the
state of charge compared to a state of charge threshold indicates
the 42-volt battery is not charged, steps 124 and 126 are again
executed which continues displaying "continue charging." In step
128 if the state of charge is at a level indicating the 42-volt
battery is charged (above a state of charge threshold), step 130 is
executed. In step 130 the display indicator may indicate
"discontinue charge" so that the vehicle operator knows the 42-volt
battery is fully charged. In step 132 the vehicle may be started
and normally operated since both of the batteries are charged. As
mentioned above, the process illustrated in FIG. 3 may be used to
charge the 42-volt battery as well as the 12-volt battery, if
needed. Of course, more than one of each type of battery may be
provided in an automotive vehicle. That is, the 42-volt battery may
be charged and fully functional prior to entering step 110
above.
[0028] Referring now to FIG. 4, if an LCD type display is not
available, a cover 150 having an electrical switch 152 coupled to
battery control module 57 may be provided. Switch 152 generates an
electrical signal as to the presence or non-presence of battery
terminal 154 of battery 66. Thus, when cover 150 is opened, battery
control module 157 enters a charging sequence. Thus, indications
may be provided through an indicator light or an audible
warning.
[0029] Thus, as can be seen, only a 12-volt battery source is
required to charge the 42-volt volt battery. The DC-to-DC converter
converts the 12-volt charging current to a voltage and current
capable of charging the 36-volt battery. Thus, particularly during
the introduction of such vehicles, commonly found 12-volt battery
systems may be readily available to charge such systems in the
event the 42-volt battery is discharged.
[0030] While particular embodiments of the invention have been
shown and described, numerous variations and alternate embodiments
will occur to those skilled in the art. Accordingly, it is intended
that the invention be limited only in terms of the appended
claims.
* * * * *