U.S. patent application number 14/039657 was filed with the patent office on 2014-01-23 for method for controlling a hybrid drivetrain and battery device in the hybrid drivetrain.
This patent application is currently assigned to Schaeffler Technologies AG & Co. KG. The applicant listed for this patent is Schaeffler Technologies AG & Co. KG. Invention is credited to Carsten Angrick, Matthias Gramann.
Application Number | 20140025248 14/039657 |
Document ID | / |
Family ID | 46275615 |
Filed Date | 2014-01-23 |
United States Patent
Application |
20140025248 |
Kind Code |
A1 |
Angrick; Carsten ; et
al. |
January 23, 2014 |
METHOD FOR CONTROLLING A HYBRID DRIVETRAIN AND BATTERY DEVICE IN
THE HYBRID DRIVETRAIN
Abstract
A method for controlling a hybrid drivetrain in a motor vehicle
having an internal combustion engine, which has a crankshaft and an
electric machine which can be operated as a motor and generator,
having a rotor operatively connected to the crankshaft, having a
torsional vibration damper operatively connected to the crankshaft,
having a battery device for exchanging electrical energy with the
electric machine, and having a control unit for controlling the
battery device and the electric machine, and a corresponding
battery device. To operate the electric machine with rapidly
changing motor and generator operation without damaging the battery
device, the electric machine is operatively connected to at least
first and second electric batteries of the battery device, where at
least part of the time one of the batteries is charged in the
rhythm of occurring residual vibrations of the torsional vibration
damper, while the other is discharged.
Inventors: |
Angrick; Carsten;
(Appenweier, DE) ; Gramann; Matthias; (Renchen,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Schaeffler Technologies AG & Co. KG |
Herzogenaurach |
|
DE |
|
|
Assignee: |
Schaeffler Technologies AG &
Co. KG
Herzogenaurach
DE
|
Family ID: |
46275615 |
Appl. No.: |
14/039657 |
Filed: |
September 27, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/DE2012/000243 |
Mar 12, 2012 |
|
|
|
14039657 |
|
|
|
|
Current U.S.
Class: |
701/22 ;
903/930 |
Current CPC
Class: |
B60Y 2400/112 20130101;
Y02T 10/6278 20130101; B60L 2210/42 20130101; Y02T 10/6226
20130101; B60W 20/00 20130101; B60W 10/26 20130101; Y02T 10/7011
20130101; B60W 2510/244 20130101; Y02T 10/7066 20130101; B60L
2210/30 20130101; B60W 30/20 20130101; Y10S 903/907 20130101; B60W
2030/206 20130101; B60W 20/13 20160101; B60Y 2300/65 20130101; B60L
50/51 20190201; Y10S 903/93 20130101; Y02T 10/7061 20130101; B60L
2270/145 20130101; Y02T 10/62 20130101; B60L 58/20 20190201; B60L
58/21 20190201; B60W 10/06 20130101; B60K 6/485 20130101; B60K 6/28
20130101; B60W 10/08 20130101; Y02T 10/70 20130101 |
Class at
Publication: |
701/22 ;
903/930 |
International
Class: |
B60W 20/00 20060101
B60W020/00; B60W 10/08 20060101 B60W010/08; B60W 10/26 20060101
B60W010/26; B60W 10/06 20060101 B60W010/06 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 4, 2011 |
DE |
102011016012.4 |
Claims
1. A method for controlling a hybrid drivetrain in a motor vehicle
having an internal combustion engine, which has a crankshaft and an
electric machine which can be operated as a motor and generator,
having a rotor operatively connected to the crankshaft, having a
torsional vibration damper operatively connected to the crankshaft,
having a battery device for exchanging electrical energy with the
electric machine, and having a control unit for controlling the
battery device and the electric machine, the method comprising the
following steps: operatively connecting the electric machine to at
least first and second electric batteries of the battery device;
and, charging the first hatter, using the electric machine, in the
rhythm of occurring residual vibrations of the torsional vibration
damper, while the second battery is being discharged.
2. The method as recited in claim 1, wherein the batteries are
switched by the control unit to a charging or discharging state,
depending on their charge condition.
3. The method as recited in claim 2, wherein the battery switched
to the charging state is charged by means of half-waves that lie
above a mean torque of the residual vibrations, which are converted
to electrical energy by driving the electric machine, and the
battery switched to the discharging state drives the electric
machine in phases of half-waves that lie below a. mean torque of
the residual vibrations to compensate.
4. A battery device for carrying out the method as recited in claim
1, comprising: first and second batteries which can be connected by
means of a plurality of current-direction-sensitive switches and a
control unit for controlling the switches, as well as a
converter.
5. The battery device as recited in claim 4, wherein in each of the
batteries a device determines the charge condition, which has a
signal connection to the control unit.
6. The battery device as recited in claim 4, wherein each battery
has a switch for charging and discharging, and the switches can be
operated alternately by the control unit,
7. The battery device as recited in claim 4, wherein the switches
are bipolar transistors having insulated gate electrodes, switched
by the control unit.
8. The battery device as recited in claim 7, wherein an inverting
logic switch is situated between each switch and an output of the
control unit, and the other two switches are connected directly to
an output.
9. The battery device as recited in claim 1, wherein the switches
can be addressed individually by the control unit to control
them.
10. The battery device as recited in claim 4, wherein the batteries
are lithium-ion batteries.
11. The battery device as recited in claim 4, wherein the batteries
have different capacities.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is filed under 35 U.S.C .sctn.120 and
.sctn.365(c) as a continuation of International Patent Application
No. PCT/DE2012/000243 filed Mar. 12, 2012, which application claims
priority from German Patent Application No. 10 2011 016 012.4 tiled
Apr. 4, 2011, which applications are incorporated herein by
reference in their entireties.
FIELD OF THE INVENTION
[0002] The invention relates to a method for controlling a hybrid
drivetrain in a motor vehicle having an internal combustion engine,
which has a crankshaft and an electric machine which can be
operated as a motor and a. generator, having a rotor operatively
connected to the crankshaft, having a torsional vibration damper
operatively connected to the crankshaft, having a battery device
for exchanging electrical energy with the electric machine, and
having a control unit for controlling the battery device and the
electric machine, and a corresponding battery device.
BACKGROUND OF THE INVENTION
[0003] Hybrid drivetrains are known from series applications in
motor vehicles. These hybrid drivetrains employ, for example, an
electric machine, which serves as a starter for the combustion
engine, as an additional or part-time solitary drive, and for
recovering the kinetic energy of the motor vehicle, as a motor and
generator; the electric machine being operatively connected to a
battery device, which stores and emits electrical energy.
[0004] A device for reducing non-uniformities of rotation of a
combustion engine is also known from German Patent No, 197 09 299
A1, where half-waves from the electric machine switched to
generator operation which lie above a mean torque of the combustion
engine are damped and the released energy is stored in the battery
unit, and the electric machine is driven to fill out half-waves
lying below a mean torque, energy being taken from the battery
device. All-in-all, the charging and discharging currents which
occur here at the battery device in the rhythm of the
non-uniformities of rotation of the combustion engine are high, so
that the battery device may not have sufficient recharging kinetics
and is damaged in the course of time due to the recharging.
[0005] Furthermore, the non-uniformities of rotation, such as
torsional vibrations in modem combustion engines are so high, for
example, due to downsizing and the like, that traditionally
employed torsional vibration dampers meet their capacity
limits.
BRIEF SUMMARY OF THE INVENTION
[0006] The object of the invention is therefore to operate a hybrid
drivetrain in such a way that, on the one hand, the torsional
vibrations of the combustion engine are damped in a satisfactory
manner, and, on the other hand, the battery device is spared. The
object of the invention is also to design a corresponding battery
device so that it has longer and better functionality, for example,
with high-frequency recharging processes between charging and
discharging.
[0007] The object is fulfilled by a method for controlling a hybrid
drivetrain in a motor vehicle, having an internal combustion
engine, which has a crankshaft and an electric machine, which can
be operated as a motor and generator, having a rotor operatively
connected to the crankshaft, having a torsional vibration damper
operatively connected to the crankshaft, having a battery device
for exchanging electrical energy with the electric machine, and
having a control unit for controlling the battery device and the
electric machine, the electric machine being operatively connected
to at least first and second electric batteries of the battery
device, and at least part of the time being charged in the rhythm
of occurring residual vibrations of the torsional vibration damper
of one of the batteries, while the other is being discharged. For
example, to damp the residual vibrations of the torsional vibration
damper through the alternating operation of the electric machine in
motor and generator mode, the recharging currents, which occur with
high frequency at the battery device, can be controlled such that
one battery is only charged and the other is only discharged. Such
an operating mode helps to conserve the batteries in the battery
device, thereby prolonging their service life.
[0008] To take account of a charge or discharge state of the
batteries, there is also a provision to switch them to a charging
or discharging mode, independent of their charged condition, by the
control unit, whose function may be provided in one or more
physical control devices and control units, in this connection,
technically known devices, for example, devices that are already
present in the batteries in an advantageous manner to determine the
charged condition, can be conveyed to the control unit, which
controls in particular the charging and discharging currents for
operating the electric machine which damps the residual vibrations.
It is understood that during the operating states of the electric
machine, for example, during the start, a recovery or the like,
both batteries may also be simultaneously charged or
discharged.
[0009] Furthermore, damping of the residual vibrations by means of
the electric machine may also be suspended if the charge state or
operating condition of the batteries falls below a specified
residual charge or residual capacity, for example, at very low
temperatures, during long drives with the support of the electric
machine or the like.
[0010] In this connection, besides controlling the battery unit,
the control unit controls the electric machine, while the battery
switched to the charging state is charged by means of half-waves
that lie above a mean torque of the residual vibrations, which are
converted to electrical energy by driving the electric machine, and
the battery switched to the discharging state drives the electric
machine by half-waves that lie below a mean torque of the residual
vibrations to compensate. The operating data for controlling the
electric machine and the battery device are provided by
corresponding sensor devices for detecting rotational
characteristics such as angles of rotation and their temporal
derivatives from shafts such as the crankshaft of the combustion
engine, the transmission input shaft(s) of a gear unit, the rotor
shaft of the electric machine, inner variables of the engine
controller of the combustion engine such as engine characteristics,
upper dead-center position and the like.
[0011] The object is also fulfilled by a battery device for
carrying out the proposed method in a hybrid drivetrain which has
first and second batteries which are alternately connectible by
means of current-direction-sensitive switches and a control unit
for connecting the switch, as well as a frequency converter. In
this case, the minus pole is preferably grounded and the plus pole
is connected by means of the switch, Alternatively, the grounding
paths of the batteries can be connected by means of the proposed
switches. To this end, the control unit issues a control signal in
a preferred manner to two alternately switching logic switches,
which switch the switches themselves, where in a preferred
embodiment a switch for the charging current and a switch for the
discharging current are provided at each plus pole, and these are
alternately switched contrary to each other. In order to damp the
residual vibrations of the torsional vibration damper, the switches
are switched alternately with reference to the batteries, so that
only one battery is charged and the other is discharged. If the
electric machine is to start the combustion engine in motor mode or
to deliver additional drive torque in a boost mode, the discharge
switches of both batteries can be switched and the charge switches
deactivated. In the case of recovery with the motor vehicle in
deceleration mode, on the other hand, the charge switches of both
batteries can be switched and the discharge switches deactivated.
It is understood that the connection layout of the switches can be
designed so that, for example, for simultaneous discharging or
simultaneous charging of both batteries the switches can be
switched accordingly, for example, the charge switches and the
discharge switches can be connected simultaneously.
[0012] In an embodiment of a battery device, devices may be
provided in each of the batteries to ascertain the charge state,
which have a signal connection to the control unit and report the
present charge state of the batteries, right down to individual
charge states of the battery cells. The control unit registers the
charge states and determines a charging plan for the various
operating states of the motor vehicle, for example, for damping the
residual vibrations of the torsional vibration damper by means of
the electric machine. The control unit registers and/or obtains for
this purpose data for appraising the operating states, for example,
starting the combustion engine, shifting the transmission,
compression and acceleration modes of the motor vehicle and the
like.
[0013] The switches may be made, for example, of active electronic
components, e.g., MOSFETs (metal-oxide-semiconductor field-effect
transistors). However, IGBTs (insulated-gate bipolar transistors)
have proven to be advantageous, which, in contrast to MOSFETs,
block completely against the switching direction due to the absence
of suppressor diodes.
[0014] Lead storage batteries and the like may be used, for
example, as the batteries. However, lithium-ion batteries have
proven advantageous due to their favorable power-to-weight ratio
and their time-dependent charging and discharging behavior.
Connecting the latter by means of the switches prevents damage,
which can occur, for example, due to subjecting them to
micro-cycles, as are necessary when damping residual vibrations by
means of the electric machine, Due to the currents that are
directed through the converter and the switches into the
corresponding battery in only one direction of flow, long charging
cycles are produced, which can he set as macro-cycles for each
battery, from a low charge state up to a prescribed charge state.
When the batteries are designed with the same capacity, each
battery may be charged alternately to approximately the maximum
capacity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The nature and mode of operation of the present invention
will now be more fully described in the following detailed
description of the invention taken with the accompanying drawing
figures, in which:
[0016] FIG. 1 is a circuit diagram for controlling the charge
states of batteries of a. battery device;
[0017] FIG. 2 is a depiction of charging processes of a
conventional battery device having a battery and the battery device
of the present invention, over time;
[0018] FIG. 3 is a depiction of the currents appearing in a hybrid
drivetrain during a compensation of residual vibrations of a
torsional vibration damper at a conventional battery device and the
battery device of the present invention, over time; and,
[0019] FIG. 4 is a circuit diagram similar to the circuit diagram
of Figure I for controlling the charge state of batteries of a
battery device.
DETAILED DESCRIPTION OF THE INVENTION
[0020] At the outset, it should be appreciated that like drawing
numbers on different drawing views identify identical, or
functionally similar, structural elements of the invention. While
the present invention is described with respect to what is
presently considered to be the preferred aspects, it is to be
understood that the invention as claimed is not limited to the
disclosed aspects.
[0021] Furthermore, it is understood that this invention is not
limited to the particular methodology, materials and modifications
described and, as such, may, of course, vary. it is also understood
that the terminology used herein is for the purpose of describing
particular aspects only, and is not intended to limit the scope of
the present invention, which is limited only by the appended
claims.
[0022] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood to one of
ordinary skill in the art to which this invention belongs. Although
any methods, devices or materials similar or equivalent to those
described herein can be used in the practice or testing of the
invention, the preferred methods, devices, and materials are now
described.
[0023] FIG. 1 shows circuit diagram 2 of battery device 1, having
first and second batteries 3, 4 with the same or different
capacity, control unit 5 and converter 6, which are connected to
each other by means of grounding line 7. Converter 6 forms the
interface to the electric machine (not shown), and transforms the
direct current of batteries 3, 4 into a plurality of alternating
current phases, of which only one phase w is depicted here
symbolically, to drive the electric machine,
[0024] Situated between converter 6 and batteries 3, 4 in each case
are two parallel-switched switches 8, 9, 10, 11 in the form of
IGBTs connected oppositely in regard to their switch position, so
that with gates of switches 8, 9, 10. 11 connected in each case
with the same signal level through logic switches 12, 13, in each
case one switch of battery 3, 4 is switched to conductive and the
other to non-conductive. in this case, the gates are connected so
that, for example, at battery 3, when a positive level is present
at output Out1 of control unit 5, switch 8 of battery 3 and switch
11 of battery 4 are switched so that when an AC signal is present
at access line 14 only battery 3 receives charging Current through
dosed switch 8, while switch 10 which is responsible for the
charging current of battery 4 remains open. In regard to discharge
current, switch 9 of battery 3 is open, and a discharge current is
able to flow from battery 4 through closed switch 11.
[0025] If the level at output Out1 is set to Low, inversely
switched logic switches 12, 13 issue a level to the gates of
switches 9, 10, so that the discharge current from battery 3 and
the charge current for battery 4 are switched through switch 9,
while switches 8, 11 remain open.
[0026] The connection of output Out! of control unit 5 is dependent
on the charge states ascertained in batteries 3, 4 by devices 15,
16, which are made up of the charge states of the individual cells
and are fed to inputs In1, In2 of control unit 5 by means of signal
lines 17, 18.
[0027] FIG. 2 shows Diagram 19, in which curves 20, 21, 22
represent the charge states of batteries against time in the range
of, for example, several minutes to several hours, where these
charge states may vary and depend among other things on the
capacity of the batteries and their electrode kinetics. The actual
excitations of the drivetrain, which the torsional vibration damper
in the drivetrain does not damp adequately, cause small waves in
the range of approximately 100 Hz in the DC section which is
downline from the converter. The depiction of the long-term
charging process and the depiction of the AC portion of the
excitations are shown overdrawn in Diagram 19 to explain the
effects.
[0028] Curve 22, identified using the symbols `+,` shows a
conventional battery device having a charge state of approximately
30% during a compensation of residual vibrations of a torsional
vibration damper by means of an electric machine, which is
connected to the single battery of the battery device. The battery
is charged and discharged here using micro-cycles, which may lie
within the range of the frequency of the occurring residual
vibrations of the torsional vibration damper. The battery may be
damaged by such micro-cycles and have a short service life.
[0029] Curves 20, 21, identified using the symbols `o` and `x`
respectively, show the charge states of battery device 1 of FIG. 1,
first and second batteries 3, 4 having different capacities--as is
evident from FIG. 2. The connection of batteries 3, 4 in accordance
with circuit diagram 2 results in the uniform charging and
discharging of the batteries over macro-cycles, which can be made
to approximate the charging and discharging processes recommended.
by the manufacturer. In this case, the battery with curve 20 has
the smaller capacity, so that it determines the macro-cycles, which
may range from a few minutes to a few hours in length. The charge
states are measured at the batteries and are registered by control
unit 5, which controls the switching of switches 8, 9, 10, 11 to
adjust the macro-cycles. In one embodiment, the battery with curve
20 is charged up to a charge state of 80% of the total capacity and
discharged to 20% thereof, which results in a recharging of between
20% and 32% of its total capacity for the battery having the
greater capacity.
[0030] FIG. 3 shows Diagram 23, with currents occurring cyclically
at battery devices during the compensation of residual vibrations
of a torsional vibration damper by means of an electric machine
connected to the batteries of the battery devices, over time. Here
curve 24, identified using the symbols `x,` shows the currents of a
conventional battery device having a single battery, which is
recharged micro-cyclically at the frequency of the alternating
currents. The batteries connected in accordance with circuit
diagram 2 of FIG. 1, on the other hand, are only charged or
discharged, so that over a relatively long macro-cycle they undergo
only positive or negative current cycles, as may be seen from
curves 25, 26 identified using the symbols `o` and respectively,
which each show the current of one battery.
[0031] FIG. 4 shows circuit diagram 2a of first and second
batteries 3a, 4a with the same or different capacity, control unit
5a and converter 6a, which are connected to each other by means of
grounding line 7a and access line 14a. Converter 6a forms the
interface to electric machine 27, and converts the DC current of
batteries 3a, 4a to a plurality of AC phases u, v, w to drive
electric machine 27. At the same time, phase-selective commutation
currents or commutation voltages in the range from 100 Hz to 1 kHz
are output, while the voltage modulations recovered by electric
machine 27 to damp the vibration of the drivetrain, which are
transmitted via converter 6a to the DC network, i.e., via access
line Ha and grounding line 7a to the batteries, lie within the
range from approximately 60 to 100 Hz. Switches 8a, 9a, 10a, Ha.
are addressed directly by control unit 5a by means of control lines
28, 29, 30, 31, and are thereby placed in a through-connected or
open state.
[0032] Because of the free design of the connection of switches 8a,
9a, 10a, 11a by control unit 5a, one of batteries 3a, 4a can be
charged while the other is being discharged. To this end, for
example, switch 8a is connected through in the direction of battery
3a and switch Ha is connected through in the direction of converter
6a, while switches 9a, 10a are open. This causes battery 3a to be
charged and battery 4a to be discharged. By closing switches 8a,
10a in the same direction, both batteries 3a, 4a are charged, for
example, during recovery of the drivetrain while the motor vehicle
is decelerating, and by closing switches 9a, 11a in the same
direction both batteries 3a, 4a are discharged simultaneously, for
example, while starting the combustion engine or when the
drivetrain is in boost mode.
[0033] Control unit 5a has a signal connection to batteries 3a, 4a
and converter 6a by means of signal lines 17a, 18a, 32, and thereby
controls the charging of the batteries and the commutation of
electric machine 27.
[0034] Thus, it is seen that the objects of the present invention
are efficiently obtained, although modifications and changes to the
invention should be readily apparent to those having ordinary skill
in the art, which modifications are intended to be within the
spirit and scope of the invention as claimed. It also is understood
that the foregoing description is illustrative of the present
invention and should not be considered as limiting. Therefore,
other embodiments of the present invention are possible without
departing from the spirit and scope of the present invention.
LIST OF REFERENCE NUMBERS
[0035] 1 battery device [0036] 2 circuit diagram [0037] 2a circuit
diagram [0038] 3 battery [0039] 3a battery [0040] 4 battery [0041]
4a battery [0042] 5 control unit [0043] 5a control unit [0044] 6
converter [0045] 6a. converter [0046] 7 grounding line [0047] 7a
grounding line [0048] 8 switch [0049] 8a switch [0050] 9 switch
[0051] 9a. switch [0052] 10 switch [0053] 10a switch [0054] 11
switch [0055] 11a switch [0056] 12 logic switch [0057] 13 logic
switch [0058] 14 access line [0059] 14a access line [0060] 15
device [0061] 16 device [0062] 17 signal line [0063] 17a signal
line [0064] 18 signal line [0065] 18a signal line [0066] 19 diagram
[0067] 20 curve [0068] 21 curve [0069] 22 curve [0070] 23 diagram
[0071] 24 curve [0072] 25 curve [0073] 26 curve [0074] 27 electric
machine [0075] 28 control line [0076] 29 control line [0077] 30
control line [0078] 31 control line [0079] 32 signal line [0080]
In1 input [0081] In2 input [0082] Out1 output [0083] u phase [0084]
v phase [0085] w phase
* * * * *