192 clutches and power-stop control – Clutches – Torque responsive
Reexamination Certificate
1999-11-03
2002-07-23
Bonck, Rodney H. (Department: 3681)
192 clutches and power-stop control
Clutches
Torque responsive
Reexamination Certificate
active
06422367
ABSTRACT:
The invention relates to a method for operating a motor vehicle as well as to a motor vehicle.
Methods for operating motor vehicles as well as motor vehicles as such are already known. More particularly a method is also known by means of which the clutch characteristic of a motor vehicle can be adapted.
A method of this kind works on the principle of the so-called bite-point adaptation. By way of example here the engine torque is measured in two different positions of the clutch. A difference value is formed from these two values of which one is detected when the clutch is opened and the second is detected at a somewhat increased value which amounts to some Nm, such as about 5 Nm to 20 Nm. This difference value of the engine torque is used for the adaptation of the clutch characteristic.
This known arrangement or this known method allows an adaptation of the clutch characteristic in a motor vehicle with an accuracy which is not to be disregarded.
In certain driving situations however improvements to this known arrangement or this known method would be desirable.
By way of example it is mentioned in this connection that the known method does not function with the desired perfection if the driver pushes down on the accelerator in the opened state since the clutch then first has to be filled. In this connection it should be further mentioned that there can be a problem when opening the clutch during the creeping (crawling operation or creep in short) or stationary state of the vehicle.
The object of the invention is therefore to provide a method for operating a motor vehicle as well as a motor vehicle which always allows a reliable and accurate adaptation of the clutch characteristic, is cost-effective, requires low structural expense and is furthermore non-susceptible to breakdown.
According to the invention it is thus proposed to provide a method for operating a motor vehicle which has at least one clutch device whereby at least one part of the dependence of the path of at least one clutch characteristic on at least one pressure value is determined and/or detected.
The invention is advantageous insofar as by using at least one pressure value to determine a clutch characteristic it is possible to avoid shifting into clutch positions which were used as reference value. Both the cost of determining the clutch characteristic can be reduced and the accuracy when determining the clutch characteristic can be improved.
In a particularly preferred method according to the invention the pressure value of the pressure of a hydraulic fluid is determined at a predetermined site. A predetermined site of this kind is for example a place on or in the vicinity of a torque sensor. A torque sensor of this kind preferably produces a pressure from a torque or produces a pressure value which is representative of the size of a torque. The torque sensor preferably builds up a pressure in dependence on the size of the engine torque. This pressure is preferably substantially proportional to the engine torque.
It should be pointed out that the term of torque sensor can be widely interpreted. According to the invention it is also proposed in this sense that instead of a pressure a force or another value can be built up for example in dependence on a torque, such as the engine torque. This value which is built up can thereby also be used as a value from which a clutch torque is determined.
In a particularly preferred method according to the invention the pressure built up by the torque sensor is detected by a torque sensor pressure sensor.
It is also preferred if the hydraulic fluid whose pressure is detected at a certain site, is enclosed by the hydraulic circuit of the motor vehicle or is in connection therewith.
The object is also achieved by a method for operating a motor vehicle according to claim 9.
According to the invention it is thus proposed to convert a preferably in a predetermined dependence relative to the first value. According to the invention it is thereby proposed that a clutch characteristic is produced at least in part directly and/or indirectly from the second value.
According to a preferred embodiment of a method according to the invention the second value is thereby produced specially for producing the clutch characteristic. This means that a value is produced which is otherwise not absolutely necessary for operating the motor vehicle.
It is preferable if the second value is a pressure and/or force value and the first value is an engine torque.
It is particularly preferred if a dependence exists at least in part between the pressure and/or force value and the size of the engine torque. This dependence is preferably linear. However other dependencies are also provided according to the invention. By way of example a parabola-shaped dependency is provided.
According to the invention it is thus proposed that n vectors and/or at least one measured value and/or n pairs of values and/or n groups of values are detected for determining and/or detecting at least one part of a clutch characteristic. The n groups of values thereby each preferably include m values. n, m are thereby &egr;N. It is pointed out that m can be different in different groups of values.
Different parameters representing a certain state are thereby detected for example in one vector. This state is for example a certain position of the clutch at a predetermined time point. The same applies for groups of values and the like.
It is preferable if the detected values and/or vectors and/or groups of values and/or measured values each represent at least one point of a clutch characteristic. The measured values are thereby preferably detected at the engaged state of the clutch.
Preferably it is harmless if a part of the measured values and/or vectors and/or groups of values are detected when the clutch is substantially disengaged.
The invention is advantageous insofar as a point of a clutch characteristic can be determined through one measuring place, such as a measuring vector or the like. In known arrangements however a reference measurement is always required in the opened state of the clutch.
In order to fix the clutch characteristic preferably only those values are detected which were recorded when the clutch was engaged. It is particularly advantageous if at least one measured value and/or at least one pair of measured values and/or at least one vector and/or at least one group of measured values represents at least one predetermined state of the motor vehicle and/or the clutch. In a particularly preferred embodiment this state is characterised—at least inter alia—in that the clutch is closed substantially at least in part.
According to a particularly preferred embodiment of the invention the parameters of at least one vector and/or at least one pair of values and/or at least one group of values are detected substantially at the same time.
The invention is particularly advantageous insofar as, unlike the prior art where values for determining a point of a clutch characteristic are recorded at various times, a point of a clutch characteristic can be determined from a value detected substantially at one time point or from a number of values detected at one time point. The known arrangement automatically requires a correspondingly long time. The inertia of the known system is thus relatively high. A system according to the invention reacts correspondingly quicker.
According to a particularly preferred embodiment of the invention at least a part of the clutch characteristic is detected at least at times independently of the differences in the engine torques.
Particularly advantageous the clutch characteristic is detected substantially completely independently of any differences. It is also preferable if the clutch characteristic is determined independently of such differences of which one value relates to a substantially engaged state of the clutch and a second value relates to a substantially disengaged state of the clutch.
According to the invention a method is thus provided for operating a motor vehicle having a clutch device
Friedmann Oswald
Hommes Georg
Reuschel Michael
Salecker Michael
Bonck Rodney H.
Darby & Darby
LuK Getriebe-Systeme GmbH
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