The present invention relates to a pressure control for the program-controlled drive of at least one pressure actuating member in order to influence the hydraulic constellation in a transmission via the pressure. Furthermore, the present invention relates to a method for the program-controlled drive of at least one pressure actuating member in order to influence the hydraulic constellation in a transmission via the pressure.
It is known to equip transmissions such as stepped automatic transmissions or continuously variable transmissions (continuously variable transmission=continuously variable transmission ratio) with pressure controls which drive one or more pressure actuating members in a transmission in order to influence the hydraulic constellation in the transmission. The required type of drive is dependent upon the transmission type as well as the transmission manufacturing series. For this reason, up to now, pressure controls or methods for the program-controlled drive of at least one pressure actuating member have been used especially adapted to a type of transmission or a transmission series, which has caused a correspondingly high cost complexity with respect to development.
The following embodiments relate to the pressure control according to the invention as well as to the method according to the invention.
One and the same pressure control having comparatively low complexity can be adapted to various transmission types or transmission series because of the following: the program-controlled drive of at least one pressure actuating member is provided in the pressure control of the invention and in the method of the invention; the program-controlled drive takes place via changes of conditions of current states to subsequent states; and, the states can be configured without change of program. Stated otherwise, the pressure control of the invention can be configured only with data for a specific transmission type or for a specific transmission series. Furthermore, the pressure control of the invention can be adapted with little complexity even to different transmission types (for example: stepped automatic, continuously variable transmission, automatic shift transmission) because at least a large part of the program can be taken over unchanged.
The following embodiments relate to the pressure control of the invention as well as to the method of the invention.
Preferably, it is provided that the states are coordinated via a status machine. The parameters of such a state machine can, for example, be defined by a table. Each entry of the table can have the following component entries:
Furthermore, criteria can be provided wherein a change from a current state to a subsequent state takes place with the satisfaction of at least one criterion. An indication as to a criterion or several criteria can likewise be the subject matter of a table entry.
The criteria, which lead to a change from a current state to a subsequent state, can include time criteria. These time criteria can either lead to a movement out of a state after a pregiven fixed time span or a state can be moved out of after a computed or estimated time span.
Furthermore, it is conceivable that the criteria whose satisfaction causes a change from a current state to a subsequent state can include event criteria. Such an event criterion can, for example, concern the reaching of a pregiven pressure. Likewise, it is, however, conceivable that the event criteria consider some transmission states and/or other ambient states.
In a preferred embodiment of the present invention, it is provided that the pressure control coacts with a shift sequence control which coordinates shifts which correspond to changes of constellations in a transmission wherein a change of the constellation results in a change of the force transmission of the transmission and wherein a sequence of shifting is subdivided into phases. In a similar manner, the method of the invention can coact with a method for coordinating corresponding shifting sequences. In this connection, embodiments are possible wherein specific phases request specific states and/or wherein specific states request specific phases.
For this purpose, the states are preferably assigned to the phases.
Several states can be assigned to one phase. In this case too, the phase boundaries are preferably coincident with state boundaries.
In a specific embodiment of the present invention, a phase e(z) is assigned to each state z and the following applies:
wherein: trgm(z)=1 is satisfied when a criterion is satisfied and wherein the phase (t) relates to a subsequent phase insofar as a phase change is to occur. From this relationship, it results that there can especially be a change from a current state to a subsequent state when the phase changes or when a criterion is satisfied. Each time the phase changes, a check is made as to whether the phase, which is assigned to the current state, is less than or equal to the new phase. In this case, the current state is left and there is a branching to a subsequent state, for example, the next state.
Preferably, it is further provided that a desired pressure trace at a time point (t) is given as:
ps(t)=psps(t)+po(t),
For the base pressure, the following preferably applies:
pB(t)=fi(z)(t,{right arrow over (x)}) with z=z(t),
wherein: fi(z) is a base pressure function which can be selected from a quantity i of base pressure functions; and, wherein the vector {right arrow over (x)} indicates the states of the transmission and/or the ambient. Each base pressure function fi(z) can, for example, be a constant, a function of the first order or another suitable function, which is provided in correspondence to the type of transmission or the transmission series.
Furthermore, the following preferably applies for the offset pressure:
wherein gj(z)(t,{right arrow over (x)}) is a pressure gradient function, which is selectable from a quantity j of gradient functions; and, wherein hk(z)(t,p0(t−1),{right arrow over (x)}) is a state change function which is selectable from a quantity k of state change functions; and wherein the vector {right arrow over (x)} indicates the states of the transmission and/or of the ambient. The functions gj(Z) and hk(Z) can also, for example, be defined by a constant, a function of the first order or another suitable function, which is provided in correspondence to the type of transmission or the transmission series.
The states of the ambient, which are considered via the vector {right arrow over (x)}, can, for example, be: the type of shift and/or the output rpm and/or the oil temperature and/or the engine rpm and/or the engine output torque and/or the throttle flap position. In this way, the pressure control of the invention as well as the method of the invention are adaptable to the most varied transmission types and vehicles.
Furthermore, it can be provided that the temperature-dependent non-linearities are compensated by a temperature compensation device. This compensation can, for example, take place via a component of the offset pressure. Likewise, it can be provided that transmission variables and/or ambient variables are coupled back via a feedback unit. A feedback of the above kind can also be considered in the form of a component of the offset pressure.
The invention will now be explained with reference to the drawings wherein:
px+1=px+Δp
wherein px is the value of the pressure before the state change, which takes place via a change from state z(x) to the subsequent state z(x+1).
px+1=pT.
The pressure pT is an absolute pressure value, that is, it is independent of the pressure present in advance of the state change. The base pressure pB is preferably inactivated in this case, that is, that changes of the base pressure pB are not considered.
px+1=pT.
Thereafter, the trace of the pressure is adjusted in correspondence to the trace of a base pressure function and a pressure trace as shown, for example, in
pT=pB−pgrad·T.
This means that the base pressure is reached after a time t=T. Here, it can be provided that the gradient is no longer automatically stopped at time point t=T; rather, there is a continuation up to the end of the state.
The above description of the embodiments according to the present invention serves only for illustrative purposes and does not serve the purpose of limiting the invention. Various changes and modifications are possible in the context of the invention without leaving the extent of the invention as well as its equivalents.
Number | Date | Country | Kind |
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100 52 794 | Oct 2000 | DE | national |
This application is the national stage of PCT/DE 01/03454, filed on Sep. 8, 2001, designating the United States.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCTDE01/03454 | 9/8/2001 | WO | 00 | 10/16/2002 |
Publishing Document | Publishing Date | Country | Kind |
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WO0235485 | 5/2/2002 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
4855913 | Brekkestran et al. | Aug 1989 | A |
5782711 | Tsutsui et al. | Jul 1998 | A |
6068576 | Tsutsui et al. | May 2000 | A |
Number | Date | Country |
---|---|---|
42 37 878 | May 1994 | DE |
0 744 565 | Nov 1996 | EP |
WO 00 34691 | Jun 2000 | WO |
Number | Date | Country | |
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20030149519 A1 | Aug 2003 | US |