Interrelated power delivery controls – including engine control – Transmission control – With clutch control
Reexamination Certificate
2003-03-27
2004-11-09
Ho, Ha (Department: 3681)
Interrelated power delivery controls, including engine control
Transmission control
With clutch control
C477S077000, C477S097000, C477S902000
Reexamination Certificate
active
06814687
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a method of varying the comfort level of gear shifts that are performed by an automated gear-shifting transmission. A set of shift parameters controlling the comfort level of gear shifts of the transmission is modified based on detected driving parameters characterizing a current traveling situation and based on a shift program mode. The shift program mode is either selected by the driver or automatically determined within a range of available shift program modes that are associated with a value range of a characteristic parameter. In determining the shift parameters as a function of the detected driving parameters, the transmission controller uses a functional correlation that depends on the current value of the characteristic parameter. In some systems, the current value of the characteristic parameter is determined on the basis of one or more of the detected driving parameters. The invention further relates to an apparatus that is operable to perform the inventive method. Also included in the scope of the invention is a method of monitoring the proper functioning of a controller device of an automated transmission.
The known state of the art offers gear-shifting transmissions for motor vehicles in numerous configurations. The term gear-shifting transmission in the conventional sense has been understood mostly to mean a manual transmission where the driver of the vehicle shifts gears by moving a manual shift lever within the constraints or tracks of a guide pattern, e.g., an H-pattern with a neutral selector track and engagement tracks for the individual gear ratios. In addition to these manually operated transmissions, some automated gear-shifting transmissions have already become known in which the movements along the selector track and the engagement tracks of the shift pattern are performed for example by actuators that are arranged on the gear-shifting transmission and are controlled by a program.
In automated transmissions of the foregoing description, a gear change is made by first taking the clutch of the vehicle out of engagement, shifting out of the currently engaged gear, shifting into the new gear, and re-engaging the clutch.
The automated gear-changing process should conform to the wishes of the driver in regard to the times at which the gear changes occur and also in regard to the level of driving comfort. The wishes of the driver may for example be determined through an evaluation of a current position of the gas pedal, e.g., whether the driver depresses the pedal lightly, whether the engine is running below idling speed, or whether the driver commands full power from the engine. In addition, the current traveling situation of the vehicle has to be taken into account for each gear shift, for example whether the vehicle is traveling uphill, or whether the engine is giving traction or running in an engine-brake mode.
The driver will expect the gear changes to run in a manner that meets his preferences. The gear-shifting process in an automatic transmission uses characteristic curves or functions for up-shifting and down-shifting. There are sets of characteristic curves corresponding to different driver-selectable programs for the control of the automatic transmission. The characteristic curves associated with the different gear ratios form a characteristic curve field or characteristic data array.
By offering a choice of control programs, the vehicle allows the driver to have an influence on the automatic shift process. With the so-called automated gear-shifting transmission (in the sense of the term that was defined above), there is the same need to take the driver's preferences into account in the gear shifting process. For example, the vehicle may have a sport-mode, i.e., a gear-shifting program that offers a sportier kind of shifts that take less time.
There may also be a winter mode for driving on a snow-covered road, in which case the entire gear-shifting process is performed gently, e.g., with a slow cutback of the engine torque before disengaging the clutch and an equally slow torque build-up after the shift has been completed. The vehicle may further have a manual mode where the driver can initiate a gear shift by operating a shift lever arranged inside the vehicle, or an economy mode for a fuel-saving way of driving, or a special mountain-driving mode. As these examples of shift-program modes illustrate, a vehicle can be equipped with a multitude of driving modes or shift program modes, as they are variously referred to, among which the driver may either make his own selection, or which may be automatically adopted by the transmission controller, e.g., after the on-board computer has detected the presence of mountainous road characteristics.
In addition to the aforementioned parameter that characterizes how fast the engine torque is lowered before disengaging the clutch and how fast the engine torque is restored to normal strength after the gear shift, there are a multitude of other parameters that have a significant influence on the transient phases of the power train during gear shifts and thus manifest themselves through the level of shifting comfort experienced by the driver. As a further example of such a parameter, one could mention the speed at which the clutch is disengaged before shifting out of the current gear and reengaged after the transmission has been shifted into the new gear.
The controller which directs the actuators for shifting the gears and for moving the clutch and which also controls the engine has to take a multitude of input parameters into account which are hereinafter referred to as driving parameters and include, e.g., the traveling speed of the vehicle, the engine rpm-rate, the current engine torque, and the currently engaged ratio, among others. Based on this input, the controller determines output parameters, hereinafter referred to as shift parameters, which include for example the force and speed of the shift actuation in the transmission, the speed at which the engine torque is cut back, the speed at which the clutch is disengaged and reengaged, and the speed at which the engine torque is restored after the new gear has been engaged.
The values that the controller can assign to the shift parameters are subject to certain constraints and limitations, because the power train of a vehicle represents a dynamic system that is capable of oscillating and has resonance frequencies. Thus, as an example, the shift parameter that determines the lowering and raising of the engine torque, or the parameter for the disengagement of the clutch, have certain ranges of values that must be avoided because they could cause resonances in the power train which would manifest themselves as a shaking of the vehicle, making gear shifts substantially less comfortable and possibly causing damage to the power train.
Based on the large number of possible driving programs or shift program modes and the driving parameters that have to be evaluated by the programs, such as e.g. the current gas-pedal depression and the currently engaged gear, there are a large number of characteristic curve fields or arrays that have to be optimized, so that the shift parameters as a function of the drive parameters will be determined in a manner that takes the engine characteristics as well as the driver's preferences into account. In the design of the transmission controller, it is therefore necessary to determine vehicle-specific shift profiles for the shift parameters and store them in the form of data arrays. Because the number of characteristic curve fields for automated gear-shift transmissions can exceed 15 and can even go higher in case additional adaptations have to be made by the transmission controller, the field of characteristic shift profiles will be represented by a very large data array which has to be determined and stored and which will have to be evaluated by the transmission controller during operation of the vehicle in order to achieve gear shifts that conform to the driver's wi
Henneberger Klaus
Jäger Thomas
Küpper Klaus
Vornehm Martin
Darby & Darby
Ho Ha
LuK Lamellen und Kupplungsbau Beteiligungs KG
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