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Patent Abstract
When a target duty of a solenoid valve of an automatic transmission
of a vehicle lies in a predetermined duty range, the solenoid valve
is driven for an adjusted over-excitation period obtained by adjusting
a base over-excitation period on the basis of an over-excitation
period adjusting value. Therefore, the solenoid valve may be normally
controlled in a region in which it shows an abnormal response characteristic.
Patent Claims
What is claimed is:
1. A method for controlling a solenoid valve of an automatic transmission
of a vehicle, the method comprising: calculating a base over-excitation
period of the solenoid valve; calculating a target duty of the solenoid
valve; determining if the target duty lies in a predetermined duty
range; calculating an over-excitation period adjusting value of
the solenoid valve when the target duty lies in the predetermined
duty range; calculating a target over-excitation period of the solenoid
valve on the basis of the over-excitation period adjusting value
and the base over-excitation period; and realizing the target over-excitation
period of the solenoid valve of the solenoid valve.
2. The method of claim 1, wherein the predetermined duty range
comprises a duty range within which the solenoid valve operates
non-linearly with respect to an applied duty.
3. The method of claim 1, wherein the predetermined duty range
lies within a range of less than 50%.
4. The method of claim 3, wherein the predetermined duty range
comprises a range of 0-30%.
5. The method of claim 1, further comprising starting operation
of the solenoid valve according to the target duty, wherein the
calculating the over-excitation period adjusting value is executed
after the starting the operation of the solenoid valve according
to the target duty, and the target over-excitation period is calculated
as a subtraction of the over-excitation period adjusting value from
the base over-excitation period.
6. The method of claim 5, wherein the predetermined duty range
comprises a duty range within which the solenoid valve operates
non-linearly with respect to an applied duty.
7. The method of claim 5, wherein the predetermined duty range
lies within a range of less than 50%.
8. The method of claim 7, wherein the predetermined duty range
comprises a range of 0-30%.
9. The method of claim 1, further comprising: determining if an
ATF temperature satisfies a predetermined temperature condition;
and determining if an applied voltage of the solenoid valve satisfies
a predetermined voltage condition, wherein the calculating the over-excitation
period adjusting value is executed only when the ATF temperature
satisfies the predetermined temperature condition and the applied
voltage of the solenoid satisfies the predetermined voltage condition.
10. An apparatus for controlling a solenoid valve of an automatic
transmission of a vehicle, comprising: a throttle opening detector
for detecting a throttle valve opening of the vehicle; a vehicle
speed detector for detecting a speed of the vehicle; a fluid temperature
detector for detecting an automatic transmission fluid (ATF) temperature
of the automatic transmission; a voltage detector for detecting
an applied voltage of the solenoid valve; a shift lever position
detector for detecting a shift lever position of the automatic transmission;
and a transmission control unit (TCU) for controlling the solenoid
valve on the basis of signals from the detectors, wherein the TCU
executes a set of instructions for a method comprising: calculating
a base over-excitation period of the solenoid valve; calculating
a target duty of the solenoid valve; determining if the target duty
lies in a predetermined duty range; calculating an over-excitation
period adjusting value of the solenoid valve when the target duty
lies in the predetermined duty range; calculating a target over-excitation
period of the solenoid valve on the basis of the over-excitation
period adjusting value and the base over-excitation period; and
realizing the target over-excitation period of the solenoid valve
of the solenoid valve.
11. The apparatus of claim 10, wherein the predetermined duty range
comprises a duty range within which the solenoid valve operates
non-linearly with respect to an applied duty.
12. The apparatus of claim 10, wherein the predetermined duty range
lies within a range of less than 50%.
13. The apparatus of claim 12, wherein the predetermined duty range
comprises a range of 0-30%.
14. The apparatus of claim 10, further comprising starting operation
of the solenoid valve according to the target duty, wherein the
calculating the over-excitation period adjusting value is executed
after starting the operation of the solenoid valve according to
the target duty, and the target over-excitation period is calculated
as a subtraction of the over-excitation period adjusting value from
the base over-excitation period.
15. The apparatus of claim 14, wherein the predetermined duty range
comprises a duty range within which the solenoid valve operates
non-linearly with respect to an applied duty.
16. The apparatus of claim 14, wherein the predetermined duty range
lies within a range of less than 50%.
17. The apparatus of claim 16, wherein the predetermined duty range
comprises a range of 0-30%.
18. The apparatus of claim 10, wherein the TCU further executes
instructions for: determining if an ATF temperature satisfies a
predetermined temperature condition; and determining if an applied
voltage of the solenoid valve satisfies a predetermined voltage
condition, wherein the calculating the over-excitation period adjusting
value is executed only when the ATF temperature satisfies the predetermined
temperature condition and the applied voltage of the solenoid satisfies
the predetermined voltage condition.
Patent Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority of Korean Application No.
10-2003-0033683, filed on May 27, 2003, the disclosure of which
is incorporated fully herein by reference.
FIELD OF THE INVENTION
[0002] Generally, the present invention relates to an automatic
transmission of a vehicle. More particularly, the present invention
relates to a method and apparatus for controlling a solenoid valve
used for hydraulic pressure control of an automatic transmission.
BACKGROUND OF THE INVENTION
[0003] Typical automatic transmissions include a torque converter
and a powertrain of a multiple speed gear mechanism connected to
the torque converter. In addition, a hydraulic control system is
provided at an automatic transmission for selectively operating
at least one operational element included in the powertrain according
to a running state of a vehicle.
[0004] Such a hydraulic control system of an automatic transmission
achieves an appropriate shift-speed corresponding to a vehicle speed
and a throttle opening, by engaging/disengaging at least one operational
element by supplying hydraulic pressure generated at an oil pump.
[0005] A solenoid valve is used for such engagement/disengagement
of an operational element, and such a solenoid valve is usually
realized as a duty control solenoid valve. A duty control solenoid
valve is usually controlled by a pulse width modulation (PWM) signal.
[0006] As shown in FIG. 5, signals for operating the solenoid valve
include a duty signal for a target shift-speed determined by a predetermined
shift pattern based on a vehicle speed and a throttle opening, an
over-excitation signal, and a chopping signal. The solenoid valve
is driven by a driving signal obtained by synthesizing the above
signals.
[0007] Applied current and motion of a plunger of the solenoid
valve show a relationship as shown in FIG. 6, according to its electrical
characteristics. When such a moving period in the motion of the
plunger of the solenoid valve is plotted with respect to 0% to 100%
of the applied duty, a characteristic graph shown as in FIG. 7 can
be obtained.
[0008] As shown in FIG. 7, when an applied duty is small, the motion
of the plunger shows a non-linear behavior with respect to the applied
duty. In this case, the moving period of the plunger becomes longer
than required, so hydraulic pressure supplied to a target frictional
element becomes shorter than required.
[0009] The information disclosed in this Background of the Invention
section is only for enhancement of understanding of the background
of the invention, and should not be taken as an acknowledgement
or any form of suggestion that this information forms the prior
art that is already known in this country to a person of ordinary
skill in the art.
SUMMARY OF THE INVENTION
[0010] The motivation for the present invention is to provide an
apparatus and method for controlling a solenoid valve of an automatic
transmission of a vehicle having non-limiting advantages of enabling
normal control of the solenoid valve in a range in which the solenoid
valve shows an abnormal response characteristic.
[0011] An exemplary apparatus for controlling a solenoid valve
of an automatic transmission of a vehicle according to an embodiment
of the present invention includes a throttle opening detector for
detecting a throttle valve opening of the vehicle, a vehicle speed
detector for detecting a vehicle speed of the vehicle, a fluid temperature
detector for detecting an automatic transmission fluid (ATF) temperature
of the automatic transmission, a voltage detector for detecting
an applied voltage of the solenoid valve, a shift lever position
detector for detecting a shift lever position of the automatic transmission,
and a transmission control unit (TCU) for controlling the solenoid
valve on the basis of signals from the detectors, wherein the TCU
executes a set of instructions for a method according to the present
invention.
[0012] An exemplary method for controlling a solenoid valve of
an automatic transmission of a vehicle according to an embodiment
of the present invention includes calculating a base over-excitation
period of the solenoid valve, calculating a target duty of the solenoid
valve, determining if the target duty lies in a predetermined duty
range, calculating an over-excitation period adjusting value of
the solenoid valve when the target duty lies in the predetermined
duty range, calculating a target over-excitation period of the solenoid
valve on the basis of the over-excitation period adjusting value
and the base over-excitation period, and realizing the target over-excitation
period of the solenoid valve of the solenoid valve.
[0013] In a further embodiment, the predetermined duty range includes
a duty range within which the solenoid valve operates non-linearly
with respect to an applied duty.
[0014] In another further embodiment, the predetermined duty range
lies within a range of less than 50%.
[0015] In a still further embodiment, the predetermined duty range
includes a range of 0-30%.
[0016] In another further embodiment, an exemplary method for controlling
a solenoid valve of an automatic transmission of a vehicle according
to an embodiment of the present invention further includes starting
operation of the solenoid valve according to the target duty, wherein
the calculating the over-excitation period adjusting value is executed
after starting the operation of the solenoid valve according to
the target duty, and the target over-excitation period is calculated
as a subtraction of the over-excitation period adjusting value from
the base over-excitation period.
[0017] In a yet further embodiment, an exemplary method for controlling
a solenoid valve of an automatic transmission of a vehicle according
to an embodiment of the present invention includes determining if
an ATF temperature satisfies a predetermined temperature condition,
and determining if an applied voltage of the solenoid valve satisfies
a predetermined voltage condition, wherein the calculating the over-excitation
period adjusting value is executed only when the ATF temperature
satisfies the predetermined temperature condition and the applied
voltage of the solenoid satisfies the predetermined voltage condition.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate an embodiment
of the invention, and, together with the description, serve to explain
the principles of the invention:
[0019] FIG. 1 is a block diagram of an apparatus for controlling
a solenoid valve of an automatic transmission of a vehicle according
to an embodiment of the present invention;
[0020] FIG. 2 is a flowchart showing a method for controlling a
solenoid valve of an automatic transmission of a vehicle according
to an embodiment of the present invention;
[0021] FIG. 3 is a timing diagram of signals used in a method for
controlling a solenoid valve of an automatic transmission of a vehicle
according to an embodiment of the present invention;
[0022] FIG. 4 is a graph for showing an effect of a method for
controlling a solenoid valve of an automatic transmission of a vehicle
according to an embodiment of the present invention;
[0023] FIG. 5 is a timing diagram of signals used in a conventional
method for controlling a solenoid valve of an automatic transmission
of a vehicle;
[0024] FIG. 6 is a graph for showing a relationship between an
applied current and a motion of a plunger in a general method for
controlling a solenoid valve of an automatic transmission; and
[0025] FIG. 7 is a graph for showing characteristics of a moving
period of a plunger of a solenoid valve with respect to an applied
duty.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] An embodiment of the present invention will hereinafter
be described in detail with reference to the accompanying drawings.
[0027] FIG. 1 is a block diagram of an apparatus for controlling
a solenoid valve of an automatic transmission of a vehicle according
to an embodiment of the present invention;
[0028] As shown in FIG. 1, an apparatus for controlling a solenoid
valve of an automatic transmission of a vehicle according to an
embodiment of the present invention controls a solenoid valve 150
included in an automatic transmission 200.
[0029] An apparatus for controlling a solenoid valve of an automatic
transmission of a vehicle according to an embodiment of the present
invention includes a throttle opening detector 105 for detecting
a throttle valve opening of the vehicle, a vehicle speed detector
110 for detecting a vehicle speed of the vehicle, a fluid temperature
detector 115 for detecting an automatic transmission fluid (ATF)
temperature of the automatic transmission 200, a voltage detector
120 for detecting an applied voltage of the solenoid valve 150,
a shift lever position detector 130 for detecting a shift lever
position of the automatic transmission 200, and a transmission control
unit (TCU) 100 for controlling the solenoid valve 150 on the basis
of signals from the detectors 105, 110, 115, 120, and 130.
[0030] The TCU 100 can be realized by one or more processors activated
by a predetermined program, and the predetermined program can be
programmed to perform each step of a method according to an embodiment
of this invention.
[0031] A method for controlling a solenoid valve of an automatic
transmission of a vehicle according to an embodiment of the present
invention is hereinafter described with reference to FIG. 2.
[0032] FIG. 2 is a flowchart showing a method for controlling a
solenoid valve of an automatic transmission of a vehicle according
to an embodiment of the present invention.
[0033] As shown in FIG. 2, firstly at step S210, the TCU 100 determines
a target shift-speed on the basis of a throttle valve opening detected
by the throttle opening detector 105, a vehicle speed detected by
the vehicle speed detector 110, and a shift lever position detected
by the shift lever position detector 130.
[0034] Accordingly, the TCU 100 calculates a base over-excitation
period of the solenoid valve 150 at step S212, and then calculates
a target duty of the solenoid valve 150 at step S214.
[0035] The base over-excitation period and the target duty may
be calculated from a predetermined base map table, as is obvious
to a person of ordinary skill in the art.
[0036] Subsequently at step S220, the TCU 100 starts operation
of the solenoid valve 150 by starting over-excitation control thereof
according to the base over-excitation period.
[0037] When shifting to achieve the target shift-speed by operating
the solenoid valve 150 is started as such, the TCU 100 determines
at step S225 if a currently output duty (i.e., the target duty of
the solenoid valve 150) lies in a predetermined duty range.
[0038] The predetermined duty range is preset to include a duty
range within which the solenoid valve operates non-linearly with
respect to an applied duty. According to an embodiment of the present
invention, the predetermined duty range lies within a range of less
than 50%, and in more detail, it is preset as a range of 0-30%.
[0039] When the currently output duty does not lie in the predetermined
duty range at the step S225, a method for controlling a solenoid
valve according to an embodiment of the present invention is finished
without adjusting the base over-excitation period.
[0040] When the currently output duty satisfies the predetermined
duty range at the step S225, the TCU 100 determines, at step S230,
if a currently output voltage (i.e., the applied voltage of the
solenoid valve 150) satisfies a predetermined voltage condition.
[0041] When the currently output voltage does not satisfy the predetermined
voltage condition at the step S230, a method for controlling a solenoid
valve according to an embodiment of the present invention is finished
without adjusting the base over-excitation period.
[0042] When the currently output voltage satisfies the predetermined
voltage condition at the step S230, the TCU 100 determines, at step
S235, if the ATF temperature satisfies a predetermined temperature
condition.
[0043] When the ATF temperature does not satisfy the predetermined
temperature condition at the step S230, a method for controlling
a solenoid valve according to an embodiment of the present invention
is finished without adjusting the base over-excitation period.
[0044] According to an embodiment of the present invention, the
predetermined voltage condition is set as the applied voltage of
the solenoid valve 150 being above or equal to a predetermined voltage,
and the predetermined temperature condition is set as the ATF temperature
being above or equal to a predetermined temperature.
[0045] When the ATF temperature satisfies the predetermined temperature
condition at the step S235, the TCU 100 calculates, at step S240,
an over-excitation period adjusting value of the solenoid valve
150.
[0046] The over-excitation period adjusting value may be obviously
set with respect to a specific solenoid valve experimentally by
a person of ordinary skill in the art.
[0047] Subsequently at step S245, the TCU 100 calculates a target
over-excitation period of the solenoid valve on the basis of the
over-excitation period adjusting value and the base over-excitation
period, and subsequently at step S250, the TCU 100 realizes the
target over-excitation period of the solenoid valve of the solenoid
valve 150.
[0048] The target over-excitation period (refer to S245) may be
calculated at the step S245 by subtracting the over-excitation period
adjusting value from the base over-excitation period.
[0049] The target over-excitation period may be realized as the
TCU 100 activates the solenoid valve 150 by the target over-excitation
period, i.e., as the TCU 100 activates it as shorter than the base
over-excitation period as the over-excitation period adjusting value.
[0050] In more detail, as shown in FIG. 3, when the base over-excitation
period for engaging a target shift-speed is calculated from the
base map table in accordance with a current vehicle running state,
such a base over-excitation period may cause a time delay in a motion
of the solenoid valve 150 from a required motion. Therefore, such
a base over-excitation period is adjusted in order to compensate
for such a time delay such that a required operation of the solenoid
valve 150 may be achieved by driving the solenoid valve with such
a compensated over-excitation period.
[0051] According to such an adjustment of the over-excitation period,
when a motion of a plunger of a solenoid valve is offset or deviated
from a required motion, such an offset or a deviation may be compensated
by reducing a peak driving period (i.e., the over-excitation period)
of the solenoid valve.
[0052] According to an embodiment of the present invention, as
shown in FIG. 4, a hydraulic pressure may be controlled as required
by adjusting control of the over-excitation of a solenoid valve,
especially when a required duty lies in a range of 10-30%.
[0053] As described above, according to an embodiment of the present
invention, when an output duty for a solenoid valve lies in a range
in which a motion of a plunger of a solenoid valve shows a non-linear
response characteristic, a control parameter is adjusted such that
the motion of the plunger becomes as required, and accordingly a
stable characteristic in a hydraulic pressure control may be achieved
and a shift control of an automatic transmission becomes more stable
and reliable.
[0054] While this invention has been described in connection with
what is presently considered to be the most practical and preferred
embodiment, it is to be understood that the invention is not limited
to the disclosed embodiments, but, on the contrary, is intended
to cover various modifications and equivalent arrangements included
within the spirit and scope of the appended claims. |