Title: Method and arrangement for controlling the internal combustion engine of a vehicle
Abstract: A method for controlling an internal combustion engine of a vehicle makes possible an acceleration of the shift operation especially of an automatic transmission or of an automated manually shifted transmission of the vehicle. In a shift operation, an operating state quantity of the engine is pregiven. This operating state quantity can be especially an engine output torque (MDES) or an engine rpm (NMOTDES). Furthermore, a torque reserve (MRES1, MRES2, MRES3) is pregiven for a rapid adjustment of the pregiven operating state quantity.
Patent Number: 6,994,653 Issued on 02/07/2006 to Hartmann, et al.
| Inventors:
|
Hartmann; Dirk (Stuttgart, DE);
Jessen; Holger (Ludwigsburg, DE);
Courtes; Mathieu (Paris, FR)
|
| Assignee:
|
Robert Bosch GmbH (Stuttgart, DE)
|
| Appl. No.:
|
456500 |
| Filed:
|
June 9, 2003 |
Foreign Application Priority Data
| Jun 08, 2002[DE] | 102 25 448 |
| Current U.S. Class: |
477/107; 477/101 |
| Current Intern'l Class: |
B60K 41/06 (20060101) |
| Field of Search: |
477/107,110,101,102,109
|
References Cited [Referenced By]
U.S. Patent Documents
| 4724723 | Feb., 1988 | Lockhart et al.
| |
| 4787044 | Nov., 1988 | Nagata et al.
| |
| 5253623 | Oct., 1993 | Melnyk et al.
| |
| 5265498 | Nov., 1993 | Fodale et al.
| |
| 5559694 | Sep., 1996 | Kraemer et al.
| |
| 5568387 | Oct., 1996 | Andersson.
| |
| 5679093 | Oct., 1997 | Desautels et al.
| |
| 5765527 | Jun., 1998 | Lehner et al.
| |
| 5947863 | Sep., 1999 | Grob et al.
| |
| 6131546 | Oct., 2000 | Vogt et al.
| |
| 6154701 | Nov., 2000 | Loffler et al.
| |
| 6155230 | Dec., 2000 | Iwano et al.
| |
| 6360154 | Mar., 2002 | Krenn et al.
| |
| 6418365 | Jul., 2002 | Loffler et al.
| |
| 6652418 | Nov., 2003 | Gutknecht-Stohr et al.
| |
| Foreign Patent Documents |
| 42 32 973 | Apr., 1994 | DE.
| |
| 2 809 059 | Nov., 2001 | FR.
| |
Primary Examiner: Estremsky; Sherry
Attorney, Agent or Firm: Ottesen; Walter
Claims
What is claimed is:
1. A method for controlling an internal combustion engine of a vehicle, the method
comprising the steps of:
inputting an operating state quantity of said engine; and,
inputting a torque reserve (MRES
1, MRES
2, MRES
3) for a rapid
setting of said operating state quantity by rapid torque increase utilizing said
torque reserve.
2. The method of claim 1, wherein said engine has an automatic transmission or
an automated manual shift transmission and said operating state quantity is inputted
when there is a shift operation; and, said operating state quantity is an engine
output torque (MDES) or an engine rpm (NMOTDES).
3. The method of claim 2, comprising the further step of inputting said torque
reserve (MRES
1, MRES
2, MRES
3) in dependence upon a difference
between said pregiven operating state quantity and an instantaneous value of said
operating state quantity.
4. The method of claim 2, comprising the further step of inputting said torque
reserve MRES
1, MRES
2, MRES
3) in dependence upon a driver command
torque (MFW) or an instantaneous engine rpm (NMOTACT).
5. The method of claim 2, wherein an ignition angle is defined for said engine
and said method comprises the further step of setting the torque reserve (MRES
1,
MRES
2, MRES
3) by shifting the ignition angle.
6. The method of claim 5, wherein the ignition angle is shifted by retarding
said ignition angle.
7. A method for controlling an internal combustion engine of a vehicle, the method
comprising the steps of:
inputting an engine output torque (MDES) or an engine rpm (NMOTDES);
inputting a torque reserve (MRES
1, MRES
2, MRES
3) for a rapid
setting of said engine output torque (MDES) or said engine rpm (NMOTDES);
inputting said torque reserve (MRES
1, MRES
2, MRES
3) in dependence
upon at least one of the following: an instantaneous phase of the shift operation
and a subsequent phase of the shift operation; and,
wherein said engine has an automatic transmission or an automated manual shift
transmission and said engine output torque (MDES) or said engine rpm (NMOTDES)
is inputted when there is a shift operation.
8. The method of claim 2, comprising the further step of inputting a first torque
reserve (MRES
1) in a first phase of a shift operation wherein a clutch is opened.
9. A method for controlling an internal combustion engine of a vehicle, the method
comprising the steps of:
inputting an engine output torque (MDES) or an engine rpm (NMOTDES) of said engine;
inputting a torque reserve (MRES
1, MRES
2, MRES
3) for a rapid
setting of said engine output torque (MDES) or said engine rpm (NMOTDES);
inputting a first torque reserve (MRES
1) in a first phase of a shift operation
wherein a clutch is opened;
inputting a second torque reserve (MRES
2) in a second phase of a shift
operation wherein a new gear stage is set; and,
wherein said engine has an automatic transmission or an automated manual shift
transmission and said engine output torque (MDES) or said engine rpm (NMOTDES)
is inputted when there is a shift operation.
10. The method of claim 9, comprising the further step of inputting the first
torque reserve (MRES
1) in dependence upon the new gear stage.
11. A method for controlling an internal combustion engine of a vehicle, the
method comprising the steps of:
inputting an engine output torque (MDES) or an engine rpm (NMOTDES);
inputting a torque reserve (MRES
1, MRES
2, MRES
3) for a rapid
setting of said engine output torque (MDES) or said engine rpm (NMOTDES);
wherein said engine has an automatic transmission or an automated manual shift
transmission and said engine output torque (MDES) or said engine rpm (NMOTDES)
is inputted when there is a shift operation; and,
said torque reserve includes a first torque reserve (MRES
1) and a second
torque reserve (MRES
2) and the method includes the further step of inputting
said second torque reserve (MRES
2) in a second phase of a shift operation
wherein a new gear stage is set.
12. A method for controlling an internal combustion engine of a vehicle, the
method comprising the steps of:
inputting an engine output torque (MDES) or an engine rpm (NMOTDES);
inputting a torque reserve (MRES
1, MRES
2, MRES
3) for a rapid
setting of said engine output torque (MDES) or said engine rpm (NMOTDES);
wherein said engine has an automatic transmission or an automated manual shift
transmission and said engine output torque (MDES) or said engine rpm (NMOTDES)
is inputted when there is a shift operation; and,
said torque reserve includes a first torque reserve (MRES
1), a second
torque reserve (MRES
2) and a third torque reserve (MRES
3); and said
method includes the further step of inputting said third torque reserve (MRES
3)
in a third phase of a shift operation wherein a clutch is closed.
13. An arrangement for controlling an internal combustion engine of a vehicle,
the arrangement comprising:
means for inputting an operating state quantity of said engine; and,
means for inputting a reserve torque (MRES
1, MRES
2, MRES
3)
for a rapid setting of said operating state quantity by rapid torque increase utilizing
said torque reserve.
14. The arrangement of claim 13, wherein said engine has an automatic transmission
or an automated manual shift transmission; and, said means for inputting said operating
state quantity functioning to input said operating state quantity when there is
a shift operation; and, wherein said operating state quantity is an engine output
torque (MDES) or an engine rpm (NMOTDES).
Description
BACKGROUND OF THE INVENTION
Known methods for controlling the shift operation in automated manually shifted
transmissions utilize torque desired values or rpm desired values, which act as
operating state inputs for the internal combustion engine or the motor in lieu
of a driver command torque or other interventions, for example, a drive slip control,
an engine drag control or the like. The control takes place in different phases
wherein suitable time-dependent courses of the engine torque or engine rpm are
pregiven by a transmission control apparatus via the torque desired values or the
rpm desired values. In a known manner, for example, the spark-ignition engine has
a dynamic which leads to the situation that the desired value inputs are actually
not converted immediately. This dynamic is caused by the physical characteristics
of the intake manifold.
SUMMARY OF THE INVENTION
The method and arrangement of the invention afford the advantage with respect
to the above that, in a shift operation, also a torque reserve is pregiven for
a rapid adjustment of the pregiven operating state quantity. In this way, the dynamic
characteristics of the engine can be improved in a short time with the torque reserve
made available so that deviations between a desired state and an actual state of
the operating state quantity can be compensated more rapidly. The error, which
is caused by the delayed conversion of the pregiven operating state quantity, thereby
becomes less. In this way, the time-dependent course of the shift operation in
an automatic transmission or an automated manually shifted transmission is accelerated
or improved in that a better correspondence is ensured between the desired value
and the actual value of the pregiven operating state quantity.
It is especially advantageous when the torque reserve is inputted in dependence
upon a difference between the pregiven operating state quantity and an instantaneous
value of the operating state quantity. In this way, the torque reserve can be adapted
to the deviation of the actual value of the operating state quantity from its desired value.
It is also advantageous that the torque reserve is pregiven in dependence upon
a driver command torque or an instantaneous engine rpm. In this way, the torque
reserve can be adapted to the instantaneous driving situation.
It is especially advantageous when the torque reserve is pregiven in dependence
upon the instantaneous phase of the shift operation and/or a subsequent phase of
the shift operation. In this way, the torque reserve can be adapted to the different
requirements during the shift operation. In this way, the time-dependent course
of the shift operation can be further accelerated and improved because of a still
better correspondence between the desired value and the actual value of the pregiven
operating state quantity. The deviations between the desired value and the actual
value of the pregiven operating state quantity can thereby be more rapidly compensated
also in the individual phases of the shift operation.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described with reference to the drawings wherein:
FIG. 1 is a block circuit diagram of an arrangement according to the invention;
FIG. 2
a is a graph showing the course of the torque as a function of
time in a shift operation;
FIG. 2
b shows the course of the engine speed (rpm) as a function of time
in a shift operation;
FIG. 3 is a schematic representation for the formation of a total torque;
FIG. 4 is a block circuit diagram for a control of rpm;
FIG. 5 is a block circuit diagram for forming a torque reserve in a first phase
of a shift operation in accordance with a first embodiment;
FIG. 6 is a block circuit diagram for a formation of the torque reserve in the
first phase of a shift operation in accordance with a second embodiment;
FIG. 7 is a block circuit diagram for a formation of torque reserve in a second
phase of the shift operation;
FIG. 8 is a block circuit diagram for selecting the torque reserve in dependence
upon the particular phase of the shift operation; and,
FIG. 9 is a block circuit diagram for the configuration of the arrangement of
the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
FIG. 1 is a section of an internal combustion engine
1, for example,
of a motor vehicle in the form of a block circuit diagram. The internal combustion
engine
1 includes an engine control
20. A transmission control
5,
an rpm sensor
30 and an operator-controlled element
25 are connected
to the engine control
20 The operator-controlled element
25 can be
an accelerator pedal of the motor vehicle. The rpm sensor
30 measures the
engine rpm of the engine
1 and conducts the measured value to the engine
control
20. In this example, and for a spark-ignition engine, the engine
control
20 controls the following: an air supply via a throttle flap, an
ignition time point and an injection quantity of fuel as shown schematically in
FIG. 1 in order to convert a pregiven operating state quantity of the engine
1.
The pregiven operating state quantity of the engine
1 can, for example,
be a desired value for an engine output torque MDES or a desired value for an engine
rpm NMOTDES. In FIG. 1, and for the sake of clarity, only the elements of the engine
1 are shown which are needed for the explanation of the method and arrangement
of the invention.
The engine control
20 receives a driver command torque MFW as an input
value MDES for the engine output torque from the accelerator pedal
25. The
engine output torque is transmitted to the drive wheels of the vehicle via an automatic
transmission (not shown in FIG. 1) or an automated manually shifted transmission.
The automatic transmission or the automated manually shifted transmission are referred
to in the following as a transmission. The invention is generally usable for any
rpm control or any desired type of transmission and indeed, generally, for rpm
control. In a shift operation of the transmission, the transmission control
5
pregives the desired value MDES for the engine output torque. The engine output
torque is identified in the following as a first operating state quantity of the
internal combustion engine
1. In a shift operation of the transmission,
the transmission control
5 furthermore outputs a desired value NMOTDES for
the engine rpm which is identified in the following as a second operating state quantity.
In a shift operation of the transmission, it is provided in accordance with the
invention that the engine control
20 outputs a torque reserve MRES for a
rapid adjustment of the particular operating state quantity, that is, the engine
output torque or the engine rpm in the above-described example. The pregiven torque
reserve MRES can be adjusted by the engine control
20, for example, by a
shift of ignition angle, especially, via a retardation of the ignition angle. In
addition, or alternatively, the pregiven torque reserve can be adjusted by the
engine control
20 also by a reduction of the fuel injection quantity. The
first-mentioned measure for adjusting the above-mentioned torque reserve MRES is
identified in the following also as an ignition angle path and the second-mentioned
measure is also characterized as an injection path in the following.
When the desired value MDES for the engine output torque or the desired value
NMOTDES for the engine rpm is requested by the transmission control
5 during
a shift operation, then the desired value can rapidly be adjusted based on the
formed torque reserve via a retardation of the ignition angle toward advance and/or
by an increase of the injection quantity of the fuel.
This is shown schematically by way of example in FIG. 3 for the engine output
torque as a first operating state quantity. The desired value MDES for the engine
output torque is pregiven by the transmission control
5. For the rapid adjustment
of this desired value MDES, the engine control
20 outputs the torque reserve
MRES. The torque reserve MRES is an additional potential for a rapid torque build-up
with this potential being made available by the engine
1 in addition to
the desired value MDES of the engine output torque. In total, a potential for a
total torque MGES is requested by the internal combustion engine
1 which
is formed from the sum of the desired value MDES for the engine output torque and
the desired value MRES for the torque reserve. This total torque MGES is adjusted
by the engine control
20 by adjusting a suitable charge and a corresponding
drive of the throttle flap and therefore the air supply to the engine.
The torque reserve MRES can be pregiven by the engine control
20 in dependence
upon a difference between the desired value for the particular operating state
characteristic variable and an actual value or instantaneous value of this operating
state quantity. The torque reserve MRES can be pregiven by the engine control
20
additionally or alternatively also in dependence upon the instantaneous driving
situation, for example, it is characterized by the driver command torque MFW or
the instantaneous engine rpm NMOTACT. In addition, or alternatively and in an especially
advantageous manner, it can be provided that the engine control
20 pregives
the torque reserve MRES in dependence upon the instantaneous phase of the shift
operation and/or a subsequent phase of the shift operation.
Various phases of the shift operation are shown in FIG. 2. In FIG. 2
a,
the course of the engine output torque M as a function of time (t) is shown. It
is, for example, assumed that the driver keeps the accelerator pedal position during
the shift operation of the transmission and therefore requests an approximately
constant driver command torque MFW. This driver command torque MFW is transmitted
from the accelerator pedal to the engine control
20. However, in a shift
operation, it is not the driver command torque MFW which is converted by the engine
control
20 but the engine output torque MDES requested by the transmission
control
5. A first phase of the shift operation takes place up to a first
time point t
1 and is characterized by the opening of the clutch. During
this first phase of the shift operation, the desired value MDES for the engine
output torque. which is requested by the transmission control
5, drops off
as shown in FIG. 2
a. The actual value MACT of the engine output torque is
made to track the desired value MDES of the engine output torque by the engine
control
20 and is shown in FIG. 2
a by the broken line. This tracking
can take place via the so-called charge path, that is, via the control of the air
supply by means of the throttle flap. Compared to the ignition angle path and the
injection path, the charge path is the least dynamic path or the slowest path.
A more rapid tracking of the actual value MACT of the engine output torque is achieved
when, additionally, a first torque reserve MRES
1 is pregiven and built up
by the engine control
20 in this first phase of the shift operation. This
can, for example, be achieved via the ignition angle path by retarding the ignition
angle or it can be achieved via the injection path by reducing the injected quantity.
If, in addition to the reduction of the charge, the ignition angle is retarded
and/or the injection quantity is reduced, the actual value MACT of the engine output
torque can track the pregiven desired value MDES more rapidly. In this way, the
first torque reserve MRES
1 effects more rapid compensation of the deviation
between the actual value MACT and the desired value MDES of the engine output torque
in the first phase of the shift operation. As not shown in FIG. 2
a, if it
should happen that the transmission control
5 requests a short-term increase
of the desired value MDES of the engine output torque during the first phase of
the shift operation, then this increase can be realized by the engine control
20
via at least a partial reduction of the already-formed first torque reserve MRES
1.
A precondition is that the formed first torque reserve MRES
1 is sufficiently
high. The first torque reserve MRES
1 makes it possible for the engine control
20 to accommodate as rapidly as possible the requests of the transmission
control
5 on the engine output torque in the first phase of the shift operation
especially because these requests are not known in advance by the engine control
20. In this way, it is ensured that the engine output torque MDES is converted
as rapidly as possible by the engine control
20 in the sense of matching
as rapidly as possible the actual value MACT of the engine output torque to the
desired value MDES of the engine output torque. The engine output torque MDES is
pregiven by the transmission control
5 in the first phase of the shift operation.
The first torque reserve MRES
1 is to be formed as close as possible to the
start of the first phase of the shift operation so that it is timely available.
In FIG. 5, a block circuit diagram for a first embodiment for realizing the first
torque reserve MRES
1 is shown. This block circuit diagram is realized in
the engine control
20. The actual value MACT of the engine output torque
is supplied by a determination device (not shown in FIG. 1) to the engine control
20 additionally. The measurement of the actual value MACT is not easily
possible. In lieu of complex sensors, a model for determining the actual value
MACT is used by the determination device. Likewise, the engine control
20
is provided with still another information which indicates the instantaneous phase
of a shift operation. This information is present in the form of a clutch bit KB.
According to FIG. 5, a first logic position
40 is provided wherein a difference
Δ is formed between the actual value MACT and the desired value MDES of the
engine output torque. The difference Δ=MACT-MDES is supplied to a first characteristic
field
35 as an input quantity. As a further input quantity, the driver command
torque MFW is supplied to the first characteristic field
35. The first characteristic
field
35 determines an amplification factor V from the two above-mentioned
input quantities. In a second logic position
45, the desired value MDES
of the engine output torque is multiplied by the amplification factor V. From this,
the first pregiven torque MRES
1 results.
In FIG. 6, the same reference numerals are used to identify the same elements
as in FIG. 5. According to the alternate embodiment of FIG. 6, the difference Δ
is again formed in the first logic position
40 between the actual value
MACT and the desired value MDES of the engine output torque, wherein Δ=MACT-MDES.
The difference Δ is supplied to a second characteristic field
55 as
an input quantity and an additional input quantity of the characteristic field
55 is the instantaneous engine rpm NMOTACT which is supplied to the engine
control
20 by the rpm sensor
30. The second characteristic field
55 determines the amplification factor V from the two above-mentioned input
quantities. The amplification factor V is multiplied by the desired value MDES
of the engine output torque in the second logic position
45 in order to
form the first torque reserve MRES
1. In this way, the first predetermined
torque reserve MRES
1 can, on the one hand, be determined in dependence upon
the difference Δ and, on the other hand, be determined in dependence upon
the driver command torque MFW in the embodiment of FIG. 5 or can be determined
in dependence upon the instantaneous engine rpm NMOTACT in the embodiment of FIG.
6. The driver command torque MFW (which can remain, for example, constant during
the shift operation as indicated in FIG. 2
a) and the instantaneous engine
rpm NMOTACT characterize the instantaneous driving situation.
The second phase of the shift operation extends from the first time point t
1
up to a second time point t
2. In this second phase, a new gear or a
new gear stage is set by the transmission. If a lower gear is set, then, in the
second phase, the desired value NMOTDES for the engine speed is increased as shown
in FIG. 2
b by the curve of the solid line. In FIG. 2
b, the course
of the desired value NMOTDES of the engine rpm is shown as a second operating state
quantity over the time (t) during the shift operation. The increase of the desired
value NMOTDES of the engine rpm is initiated at a third time point t
3 which
lies in the second phase between the first time point t
1 and the second
time point t
2. This desired value is connected to a short-term increase
and a subsequent lowering of the desired value MDES of the engine output torque
as can be seen in FIG. 2
a between the third time point t
3 and
the second time point t
2. When upshifting, an opposite course correspondingly
results, that is, a drop of the desired value NMOTDES of the engine rpm from the
third time point t
3 on in accordance with the dot-dash line in FIG.
2
b and a short-term drop and follow-on increase of the desired value MDES
of the engine output torque in accordance with the dot-dash line in FIG. 2
a
between the third time point t
3 and the second time point t
2
in the second phase. In the second phase, it is of primary importance that
there is a rapid adjustment of the desired value NMOTDES for the engine rpm. The
second phase is therefore also characterized as rpm control phase. The engine rpm
can, for example, be controlled by means of a PID-controller
60 within the
engine control
20. Here, a difference ΔN between the actual value
NMOTACT and the desired value NMOTDES of the engine rpm are supplied to the PID-controller
60. The difference ΔN of the engine rpm results, for example, as ΔN=NMOTACT-NMOTDES.
At a third logic position
65, a P-component P of the PID-controller
60
is added to a second torque reserve MRES
2. An I-component I of the PID-controller
is added to the sum formed in a fourth logic position
70. A D-component
D of the PID-controller
60 is then added to the sum formed here in a fifth
logic position
75. The sum formed in this way is identified in FIG. 4 by
MGES′ and defines the output of the PID-controller
60. The output
MGES′ of the PID-controller
60 is supplied to a limiting member
80
which limits the output MGES′, as required, upwardly to an upper permissible
torque limit or downwardly to a lower permissible torque limit. The output of the
limiting member
80 is the desired value for the total torque MGES. This
total torque corresponds to the output MGES′ of the PID-controller
60
when the output MGES′ neither exceeds the upper permissible torque limit
nor drops below the lower permissible torque limit.
In the case of a downshifting into the second phase of the shift operation, a
short-term increase of the desired value MDES of the engine output torque is required
in order that the actual value NMOTACT of the engine rpm tracks the increased desired
value NMOTDES. So that this can take place in the most rapid way possible, a second
pregiven torque reserve MRES
2 is to be formed by the engine control
20
as early as possible in the second phase (that is, already between the first time
point t
1 and the third time point t
3) and, in accordance
with FIG. 3, the corresponding total torque MGES is to be made available via the
charge path. The second torque reserve MRES
2 results, in turn, from the
adjustment of the ignition angle path and/or the injection path.
In FIG. 7, a block circuit diagram for forming the second torque reserve MRES
2
is shown. In a sixth logic position
85, the difference ΔN′
is formed for the second phase of the shift operation from the desired value NMOTDES
and the actual value NMOTACT of the engine rpm, for example, as follows: ΔN′=NMOTDES-NMOTACT.
The desired value NMOTDES of the engine rpm is pregiven for the second phase
of the shift operation by the transmission control
5; whereas, the actual
value NMOTACT of the engine rpm is received in the engine control
20 from
the rpm sensor
30. The block circuit diagram of FIG. 7 is, for example,
realized, in turn, in the engine control
20. The difference ΔN′
of the engine rpm is an input quantity of a third characteristic field
90.
A further input quantity of the third characteristic field
90 is the driver
command torque MFW. In an alternate embodiment, the input quantity could also be
the instantaneous rpm NMOTACT. From the above-mentioned input quantities of the
third characteristic field
90, the second predetermined torque reserve MRES
2
can, for example, be derived directly.
The same applies also for upshifting in the second phase wherein a short-term
drop and subsequent increase of the desired value MDES of the engine output torque
is required between the third time point t
3 and the second time point
t
2 for lowering the desired value NMOTDES of the engine rpm.
With the second pregiven torque reserve MRES
2, an adaptation of the actual
value NMOTACT to the desired value NMOTDES of the engine rpm can be obtained especially rapidly.
Usually, it is known already at the beginning of the first phase whether,
in the second phase, there is to be an upshifting or a downshifting. Correspondingly,
the first predetermined torque reserve MRES
1 can be pregiven in the first
phase of the shift operation already in dependence upon the jump in engine rpm
to be expected from the second phase so that at the beginning of the second phase,
at most only slight corrections are to be carried out on the torque reserve in
dependence upon the difference ΔN′ of the engine rpm in order to form
the second pregiven torque reserve MRES
2. There can therefore be a start
of the increase of the desired value NMOTDES of the engine rpm already at the first
time point t
1 or shortly thereafter so that the second phase can be
still further considerably shortened and, above all, the time difference between
the third time point t
3 and the first time point t
1 can be
virtually eliminated. In this way, the shift operation is further accelerated.
Generally, a torque reserve is not needed for a reduction of the desired
value MDES of the engine output torque. This torque reserve is nonetheless purposeful
for the first phase of the shift operation in the following three cases.
In the first case, the first pregiven torque reserve MRES
1 makes possible,
as described, also a short-term conversion of a short-term desired torque increase
pregiven by the transmission control
5. The first pregiven torque reserve
MRES
1 should be selected to be as small as possible in order to just be
sufficient for the desired torque increases in the first phase which possibly occur
for a short time. Otherwise, the adjustment of the actual value MACT to the desired
value MDES of the engine output torque can be tracked very rapidly via the charge
path by reducing the degree of opening of the throttle flap because the air supply
can be reduced very rapidly in this way. The first pregiven torque reserve MRES
1
is to be held as low as possible and with this torque reserve MRES
1, the
total torque MGES must not be adjusted to be significantly greater than the desired
value MDES of the engine output torque. This variation affords the advantage that
the torque tracking takes place primarily via the charge path and therefore leads
to low raw emission components in the exhaust gas and to a reduction in fuel consumption.
In the second variation, as described, an adaptation of the actual value MACT to
the falling desired value MDES of the engine output torque can likewise take place
via the charge path as well as via the ignition angle and/or the injection path
and can therefore be accelerated. In this second variation, a larger first torque
reserve MRES
1 is, as a rule, therefore realized than in the first variation.
In this way, the actual value MACT can be adapted still more rapidly to the desired
value MDES of the engine output torque than in the first variation. The first phase
of the shift operation can be shortened in this way; however, this takes place
at the cost of the raw emission component in the exhaust gas and of the fuel consumption.
The third variation builds upon the second variation and uses the first torque
reserve MRES
1, which is formed for the rapid reduction of the engine output
torque, also for the second phase of the shift operation. The first torque reserve
MRES
1 is already pregiven in the first phase of the shift operation in dependence
upon the shift operation, which is provided in the second phase, that is, the new
gear stage which is to be set so that this first torque reserve MRES
1 can,
if required, be used in the second phase, as required, as a second torque reserve
MRES
2. The time for the formation of the second pregiven torque reserve
MRES
2 in the second phase can be shortened in this way as already described.
In this way, the second phase, can, overall, be shortened. The shift operation
is therewith overall accelerated. Accordingly, if, at the beginning of the first
phase of the shift operation, it is already known that downshifting will occur
in the second phase then, in the first phase, an increased first reserve torque
MRES
1 can be pregiven which is available for the necessary rpm increase
in the second phase already at the first time point t
1. If, in the first
phase, it is already known to which desired value NMOTDES the engine rpm is to
be increased in the second phase of the shift operation, then, in the first phase
of the shift operation, the second torque reserve MRES
2 can already be pregiven
in the first phase of the shift operation according to the block circuit diagram
of FIG. 7. The second pregiven torque reserve MRES
2 is therefore pregiven
for the first phase as well as for the second phase of the shift operation, that
is, it is the same for the first and second phases of the shift operation. In the
first phase of the shift operation, the second pregiven torque reserve MRES
2
is built up in that the ignition angle is retarded and/or the injection quantity
is reduced. In this way, the torque reduction is considerably accelerated in the
first phase. While according to FIG. 3, the total torque MGES is reduced simultaneously
via charge reduction, the second pregiven torque reserve MRES
2 is built
up and therefore increased. This leads to a rapid drop of the charge magnitude
which is still available for the realization of the desired value MDES of the engine
output torque. At the latest, at the end of the first phase (that is, at time point
t
1), the pregiven second torque reserve MRES
2 is available so
that the rpm increase can immediately be started.
If it is already known in the first phase of the shift operation that upshifting
will take place in the second phase, then there will be a drop of the desired value
NMOTDES of the engine rpm in the second phase wherefor no torque reserve is required.
The reduction of the rpm is logically coupled to a reduction of the engine output
torque. Only when the lower engine rpm is adjusted and must be held, a slight increase
of the engine output torque is again required toward the end of the second phase
as shown in FIG. 2
a. For this case, the second pregiven torque reserve MRES
2
can be provided in order to realize as rapidly as possible this increase of the
desired value MDES of the engine output torque toward the end of the second phase.
In this case, the second pregiven torque reserve can, however, still be built up
easily within the second phase because a torque drop is first present. This torque
drop can be realized in the same way as in the previously described first phase
and can be realized for forming the second pregiven torque reserve MRES
2.
In this case, the second pregiven torque reserve MRES
2 also must no longer
be pregiven in dependence upon the rpm difference but in dependence upon the torque
difference to be realized at the end of the second phase between the actual value
MACT and the desired value MDES of the engine output torque and therefore as described
in FIG. 5 or in FIG. 6. In this way, the formation of the second pregiven torque
reserve MRES
2 is not required already in the first phase of the shift operation
so that there the adaptation between the actual value MACT and the desired value
MDES of the engine output torque can take place in accordance with variation
1
almost completely via the charge path and, in this way as little raw emissions
as possible occur.
In the third phase of the shift operation, which starts at the second time point
t
2, the clutch is closed at constant desired value NMOTDES for the engine
rpm and the desired value MDES for the engine output torque is again increased
to the driver command torque MFW. The actual value MACT of the engine output torque
is to track as rapidly as possible the driver command torque MFW as shown in FIG.
2
a by the broken line. This can take place via a third pregiven torque reserve
MRES
3 which is determined as also the first pregiven torque reserve MRES
1
in accordance with FIG. 5 or
6. The third pregiven torque reserve MRES
3
is formed as rapidly as possible at the start of the third phase starting from
the second time point t
2, as described on the ignition angle path and/or
on the injection path.
In. FIG. 8, a block circuit diagram is shown for selecting the total torque MGES
for the individual phases of the shift operation. This block circuit diagram is
likewise realized in the engine control
20. In addition to the clutch bit
KB (which indicates whether a shift operation is present), the engine control
20
furthermore is supplied with an rpm bit DB which indicates whether the engine control
phase is active, that is, the second phase of the shift operation. The clutch bit
KB and the rpm bit DB are supplied by the transmission control
5 to the
engine control
20. In a seventh logic position
95, the instantaneous
desired value MDES of the engine output torque is added to the instantaneous torque
reserve. Only the desired values MDES for the engine output torque, which are supplied
directly by the transmission control
5, are considered. They are present
in the first and third phases of the shift operation. Accordingly, the instantaneous
pregiven torque reserves are the first or the third pregiven torque reserves (MRES
1,
MRES
3). In the second phase of the shift operation, the transmission control
5 supplies the desired value NMOTDES for the engine rpm from which the engine
control
20 then determines the particular required torque value MDES for
the engine output torque which is needed in order to adjust the desired value NMOTDES
for the engine rpm. The additive logic coupling of the instantaneous desired value
MDES of the engine output torque to the second torque reserve MRES
2 takes
place in an eighth logic position
100. The second torque reserve MRES
2
is pregiven in the second phase of the shift operation. A first controlled switch
50 connects either the output of the seventh logic position
95 or
the output of the eighth logic position
100 to a first input
110
of a second controlled switch
105. The first controlled switch
50
is controlled by the rpm bit DB. During the first phase of the shift operation,
the rpm bit DB is set and drives the first controlled switch
50 in such
a manner that this switch connects the output of the eighth logic position
100
to the first input
110 of the second controlled switch
105. Otherwise,
the rpm bit DB is reset and drives the first controlled switch
50 in such
a manner that this switch connects the output of the seventh logic position
95
to the first input
110 of the second controlled switch
105. The second
controlled switch
105 has the value zero Nm at a second input
115.
The second controlled switch
105 is controlled by the clutch bit KB. This
clutch bit KB is set during the shift operation. In the set state, the clutch bit
KB drives the second controlled switch
105 in such a manner that the switch
connects the first input
110 to its output. Outside of the shift operation,
the clutch bit KB is reset and drives the second controlled switch
105 in
such a manner that this switch connects the second input
115 to its output.
In this way, during the shift operation, the total torque MGES is output at the
output of the second switch
105. The total torque MGES is formed from the
sum of the instantaneous desired value MDES of the engine output torque and the
just then instantaneous torque reserves (MRES
1, MRES
2, MRES
3).
Otherwise, the value zero Nm is outputted at the output of the second switch
105.
It can then be provided that the engine control
20 realizes the total torque
value MGES via the charge path and therefore the air supply with the output of
a value unequal to zero at the output of the second controlled switch
105.
If the value zero is outputted at the Output of the second controlled switch
105,
then the engine control
20 checks whether a torque request is present from
the other modules of the vehicle, for example, from the accelerator pedal
25,
in order to realize this request, for example, the driver command torque MFW.
In FIG. 9, a block circuit diagram is provided for the arrangement of the invention
which can likewise be implemented in the engine control
20 and is identified
in FIG. 9 with reference numeral
120. The arrangement
120 includes
means
125 for receiving the desired value MDES of the engine output torque,
especially from the transmission control
5 and of the actual value NMOTACT
of the engine rpm from the rpm sensor
30. The means
125 furthermore
receive the driver command torque MFW from the accelerator pedal
25. The
means
125 furthermore receive the rpm bit DB from the transmission control
5 and the clutch bit KB. The means
125 are connected to means
10
for inputting the torque reserve in accordance with the block circuit diagram of
FIG. 5, FIG. 6 or FIG. 7. The means
125 and the means
10 are connected
to means
15 for determining the total torque MGES in accordance with the
block circuit diagram of FIG. 8. The total torque MGES is realized via the charge
path in the manner described.
With the method of the invention and the arrangement of the invention, the shift
operation and therefore the disadvantageous interruption of the power connection
between the engine and the drive train of the vehicle is accelerated during the
shift operation of the transmission. To consider the instantaneous driving situation
in the formation of the particular torque reserve the driver command torque MFW
and the actual value NMOTACT of the engine rpm are presented by way of example.
In addition, or alternatively, additional quantities can be considered in the formation
of the particular torque reserve, which quantities describe the driving state,
the transmission ratio, the type of driver and/or the driving behavior (for example,
spontaneous or economical). As to the driving state and the transmission ratio,
these quantities can be measured by suitable measuring devices and, as to the type
of driver and the driver behavior, these quantities can be learned from previous
driving situations.
For drivers who want a more rapid or more spontaneous response performance of
the vehicle, a higher respective torque reserve in the corresponding phases of
the shift operation can be made available than for drivers who value a more economic
driving style. A higher driver command torque MFW or a higher actual value NMOTACT
of the engine rpm can be so interpreted and can be so realized by the first characteristic
field
35, the second characteristic field
55 or the third characteristic
field
90 that a larger particular torque reserve is formed in the individual
phases of the shift operation because the assumption was of a driver having a desire
for a more spontaneous response performance of the vehicle. For a lower driver
command torque MFW or a lower actual value NMOTACT of the engine rpm, one proceeds
instead from a driver concerned with respect to consumption and a corresponding
lower particular torque reserve for the individual phases of the shift operation
is pregiven by the first characteristic field
35, the second characteristic
field
55 and the third characteristic field
90.
It is understood that the foregoing description is that of the preferred embodiments
of the invention and that various changes and modifications may be made thereto
without departing from the spirit and scope of the invention as defined in the
appended claims.
*
