DE102018003901B3 - Sensor system for gear selection detection in a motor vehicle - Google Patents

Abstract

Disclosed is a motor vehicle 5 with an external shift operation 25 for engaging gears of a manual transmission 20 and an internal shift operation 50 partly projecting into the transmission for shifting the gears. The motor vehicle has a first sensor 27 mounted to the vehicle body and a second sensor 70 mounted in the kinematics chain between external shift actuator 25 and internal shift actuator. Both sensors are each a MEMS sensor for detecting translational accelerations in three mutually different spatial directions and for detecting rotational speeds in two or three different directions of rotation, or include these.

Description

The invention relates to a motor vehicle with an external switching operation for a manual transmission.

Motor vehicles with an internal combustion engine and an associated manually operable transmission usually have an external shift operation with a middle console area upwardly projecting shift or selector lever for manual engagement of the gears. The shifting of the gears within the transmission takes place with an internal selector mechanism partially projecting into the transmission. Between external and internal gearshift is a kinematic chain, with the mechanical gear selection of the driver is converted into a gear shift in the transmission.

Well-known are gear recognition sensors with which the gearshifted within the transmission gear can be determined, for example. Installed in the Chevrolet Corvette (Bj. 2018).

Also known is a gear selection detection sensor, with which the gear selected by the driver with the shift or selector lever, e.g. the selected by him 3rd gear of a manual transmission, can be detected. This sensor system comprises a sensor for determining the engine speed and a sensor for determining the vehicle speed. Such a gear selection detection sensor allows to calculate the gear engaged with the known ratios in the transmission, thus requiring a closed clutch.

As a rule, a gear recognition sensor and a gear selection detection sensor provide the same result, i. the same gear of the gearbox. Deviations in manual transmissions can occur in the rare cases of the Le Mans effect and the inverse Le Mans effect. In the case of the Le Mans effect, the driver selects the first gear with the shift lever, but the gearbox is switched to reverse gear. In the inverse Le Mans effect, it is exactly the opposite, i. the reverse gear is selected but the first gear is switched. Both effects have their cause in the inertia of a very fast accelerated shift shaft of the internal shift operation.

The DE 10 2017 206 335 A1 further describes a gear shift timing system that can indicate unnecessary shift commands when using cruise control.

It is an object of one embodiment of the invention to provide a gear selection detection sensor that operates with both the clutch and the clutch open.

It is an object of another embodiment to provide a gear selection detection sensor that can predict the occurrence of the Le Mans or Reverse Le Mans effect so that countermeasures can be taken to avoid inadvertently driving in the wrong direction and associated hazards can be.

These and other objects are achieved with the features of the independent claim. Structural refinements and other advantages will become apparent from the dependent claims.

A solution to the above object is a motor vehicle with an external shift operation for engaging gears of a manual transmission, in particular designed as a step or as a manual transmission, and with a partially projecting into the transmission internal shift operation for shifting the gears. The motor vehicle has a first sensor mounted to the vehicle body and a second sensor mounted in the kinematics chain between the external shift operation and the internal shift operation. The first sensor and the second sensor each comprise or comprise a MEMS sensor for detecting translational accelerations in three mutually different spatial directions, and for detecting rotational speeds in two or three different rotational directions, the directions each depending on a Cartesian coordinate system Number of directions is two- or three-dimensional. The MEMS sensor is thus a two- or three-axis gyroscope and at the same time a three-axis acceleration sensor. In terms of linguistic simplicity, this type of sensor is referred to below as a MEMS sensor or simply as a "sensor".

The aforementioned kinematics chain comprises at least the internal shift operation and the external shift operation itself. In addition, switching cables and selector cables located therebetween or alternatives thereto for transmitting the desired transmission to the transmission, for example a shift linkage, are transmitted.

The manually shiftable transmission can be a manual step transmission, a manual transmission with electromotive torque assistance, an automated manual transmission, a dual clutch transmission, or even an automatic transmission, in all cases assuming that the driver manually sets a gear ratio, so that the mechanical choice is detectable. Common to these variants is that the driver determines the gear to be engaged by actuating a shift lever.

The first sensor is mounted to the vehicle body and can be, for example, an airbag sensor, an impact sensor arranged in the bumper region, for example, or an ESP (electronic stability program) sensor which, due to its position, can not make any relative movement to the body. Thus, an already existing sensing element, if it already exists as a MEMS sensor, be used for the further purpose of gear selection detection.

MEMS stands for microelectromechanical system, which is a miniaturized electronic sensor when used as a sensor. In the present case, it senses axial or translational accelerations for three mutually different and in particular mutually orthogonal spatial directions and additionally rotational accelerations in two or three mutually different and in particular mutually orthogonal spatial directions.

The second sensor is arranged to be movable relative to the first sensor. Because of the above-mentioned properties of the MEMS sensor, a translational and preferably a rotational relative movement of the second sensor relative to the first sensor is possible.

If the first sensor is fixed to the body and the second sensor is arranged in said kinematics chain, the movement of that element of the kinematics chain to which the second sensor is attached can be calculated from the sensor data of both sensors by coordinate transformations. Since the respective position of the relevant elements of the kinematics chain is mutually known by design, this in turn allows the movement and also the position of the shift lever to be determined so that the two MEMS sensors together assume the function of a gear selection sensor. The gear selection function works even if the driver has passed the clutch pedal.

The second sensor may be attached to or in an axially movable and / or rotatable part or element of the kinematic chain so that it can follow its movements.

In particular, the attachment of the second sensor to a rotatable element lends itself to, because attaching the MEMS sensor to an axially moving element with time adjusts a signal drift, which complicates the evaluation of the sensor data or and reduces their significance. When sensing a rotational movement, it is better to use the functionality of the gyroscope, which provides angular velocities that must be integrated to calculate relative angular positions. Due to the integration, however, a drift occurs because an unknown measurement error is also integrated.

In the idle state of the sensor, the three axially measuring acceleration sensors in, for example, the x, y and z directions produce a vector g which corresponds in magnitude to the gravitational acceleration and points in the direction of the earth. This makes it possible to determine the position of the sensor relative to the vector g or to the earth. With a movement of externally entered accelerations, so not the gravitational acceleration) they are inaccurate.

In interaction, the sensors of the MEMS sensor are well suited to reliably determine the absolute position of the shift lever, and this stable and without drift.

The provision of the two MEMS sensors or such a gear selector sensor ensures a determination of the shift lever position in space and thus the gear selected by the driver. The gear selection is independent of whether the clutch is open or closed.

As an electronic component, the MEMS sensor has the potential to provide the shift lever position with high sampling frequency and thus high time resolution so that it can provide predictive gear selection detection or shift intent recognition.

According to one embodiment, the second sensor may be attached to an axially and / or rotatable part of the external shifting operation. The said part may in particular be the shift lever or its actuating knob on an imaginary spherical surface moving and thus rotatable shift knob, and the data can be transmitted either by cable or wirelessly to an evaluation unit, eg. The engine control unit. However, it is also possible to select a part or element of the external shifting mechanism which is suitably mechanically coupled to the shift lever and which follows the shifting process kinematically as a movable part.

The embodiment of the last paragraph requires a high accuracy compared to other points of the kinematic chain, since the second sensor is located at the beginning of the kinematic chain and tolerances with respect to a relative position of the said element to the shift lever are by definition zero. In addition, in other position of the second sensor, the sensor signal due to the required mechanical transmission of the gear selection is delivered with a time lag, so that attachment of the second sensor as described above on the external switching operation for the predictive gear selection detection is particularly suitable.

Alternative positions of the second sensor are also axially and / or rotatable parts of a shift linkage, a shift shaft, a shift mass or a vibration absorber of the internal shift operation.

An embodiment of the motor vehicle has a microcontroller which is set up to determine the engaged gear on the basis of the data of the first and second sensors. The microcontroller may be, for example, the engine control unit.

In order to enable a predictive gear selection recognition, it requires sufficiently short time intervals between two position data supplied by the sensor, since otherwise the accuracy of the gear selection prognosis is too low. In order to ensure sufficient accuracy, another embodiment provides that the first and second sensors are designed to deliver data to the microcontroller in real time during gear selection. In real time, this means that sensor data are supplied to the microcontroller with a time interval of less than 10 ms, particularly preferably less than 5 ms.

In a further embodiment, the microcontroller is further configured to first determine current positions of the shift lever during a gear selection and, based thereon, to predict the gear the driver will engage. Such, usually software-implemented predictive training is carried out using well-known in the field of machine learning self-learning algorithms, with which the skilled person is well familiar. Only examples of such algorithms are SVM algorithms (support vector machines), decision trees or artificial neural networks.

If the gear presumed to be engaged or predicted or alternatively the gear already engaged is determined, then a further embodiment provides for use, depending on the gear thus determined, to adapt the crankshaft speed to the rotational speed of the transmission input shaft in order to make the engagement process more comfortable and less prone to wear do. By using the predicted gear, this adaptation can also be done very early, which in comparison to a use of the already inserted gear again leads to more comfort and even less wear.

In the event that a manual transmission with an electromotive torque assistance is used, can be based on the already inserted or the predicted gear and alternatively or cumulatively to the procedure of the last paragraph make an adjustment of the speed of the transmission input shaft and thus support the synchronization process. This is particularly appropriate when the electric motor is arranged on the transmission input shaft and can apply a torque to this shaft.

A further embodiment provides that the transmission has a gear recognition sensor for detecting the gearshifted gear and the microcontroller is set up to determine whether the predicted or already engaged via the external shift operation gear on the one hand and the gear on the other hand differ. If the two gears differ, the above-mentioned Le Mans effect and the inverse Le Mans effect can be detected and a suitable countermeasure taken. Thus, an optical or acoustic warning can be issued or the driver's desired acceleration can be at least reduced, in particular if a collision with another road user is to be feared with the aid of detectors.

In another embodiment, the motor vehicle is operable in a sailing mode, i. For example, the vehicle is configured to taxi while the vehicle is in motion, particularly at speeds greater than 5 to 100 km / h or more, with the clutch disengaged, with the engine either idling or off. In this operating mode, which serves to save fuel, the microcontroller is set up to initiate the sailing mode initiated by the driver, for example, by stepping the clutch pedal, to determine the gear suitable for the current driving conditions and to issue a visual or audible warning in the event of a difference from the predicted gear. The detection of this difference can also be used to prevent the insertion of the selected new gear. In this way, either a transmission damage can be prevented (if the driver's selected gear ratio is too small) or a stalling can be reduced (if the selected on the driver side gear ratio is too large).

• 1 ein Kraftfahrzeug,
• 2 eine externe Schaltbetätigung,
• 3 eine interne Schaltbetätigung.

The invention will be explained in more detail below on the basis of an exemplary embodiment with reference to the figures to be considered by way of example, in which the same reference numerals designate the same objects. It shows:

• 1 a motor vehicle,
• 2 an external switching operation,
• 3 an internal switching operation.

1 schematically shows a motor vehicle 5 with an internal combustion engine 10 in the form of an Otto engine, its crankshaft 15 the waves a gearbox 20 , in this case, a manual transmission with 6 gears, drive. The gears are engaged by the driver by hand by pressing the external gearshift 25 , Also marked is a body-mounted first MEMS sensor 27 in the front, chosen as the commercially available InvenSense MPU-6050 module. This has a 3-axis gyroscope for detecting rotational speeds and a 3-axis accelerometer for detecting axial movements. The measured values are digitized by the sensor via A / D converter and can be read out by cable.

2 shows the internal switching operation 50 , This has a pin 60 to which the dialing cable 45 is attached, as well as a pin 65 to which the shift cable 40 is attached. For an external switching operation 25 with H-circuit diagram causes a movement of the shift lever along a shift gate, so for example by gear 1 Access 2 , a pull on pin 65 with rotation of the switching shaft 55 , In a movement of the shift lever in the respect. The shift gate vertically arranged Wählgasse is at pin 60 pulled, resulting in a movement of the shift shaft along its longitudinal axis. The first sensor 27 identical second arranged inside the gear sensor 85 can be at the selector shaft 55 be attached, alternatively also on the shift mass 75 or a vibration absorber coupled thereto 80 ,

3 shows an external switching operation 25 for shifting the gears of the manual transmission 20 with a gear lever 30 (sometimes called selector lever) with knob 35 , The insertion of the gears causes a movement of the shift cable 40 in the cable longitudinal direction (either forward or backward, depending on whether one switches in the smaller or the larger gear of the shift gate), the pin at the transmission end 65 connected is.

The second sensor 70 is directly on the shift lever 30 attached and thus at the beginning of the kinematic chain. The first sensor 27 , the second sensor 70 and the gear recognition sensor integrated in the gearbox interior 85 send their data via data lines 90 . 90 ' . 90 " to a microcontroller 95 ,

The gear selection is done as follows:

The first body-mounted MEMS sensor 27 senses its translational acceleration and its rotational speed in three spatial directions relative to the environment. The acceleration values are absorbed by the motor vehicle 5 moving coordinate system K1 on. Upon actuation of the pivotable about a pivot lever 30 the second sensor moves 70 on a spherical surface, resulting from second, identical MEMS sensor 70 whose measured acceleration and rotation speed values are a second coordinate system K2 span with a coordinate transformation with K1 is brought to cover. If you move the gear lever 30 , this changes the position of the second sensor in the coordinate system. Overall, thus, the position of the second sensor can be 70 calculate relative to the body.

The two sensors 27 and 70 allow measurements with a sampling frequency of at least 200 Hz, which provides measured values in time intervals of 3 ms and thus in real time, but also a faster data delivery is of course possible.

From the detected gravitational acceleration by the MEMS sensors 27 or. 70 can be determined by evaluation software based on the acceleration of gravity of the absolute deflection angle of the equipped with a ball joint lever relative to its neutral position (shift lever in the selector gate and at the same time in the shift gate between 3rd and 4th gear) and thus its position in the H-diagram. The same is possible with the detected rotational speeds, although here a relative angle is determined, which is related to the start of the measurement. The deflection angle consists of a selection angle and a switching angle. The Wählwinkel reflects the pivoting of the shift lever in its ball joint in its movement along the selection gate, the switching angle accordingly when moving in a shift gate.

The shift lever positions determined only from the acceleration measurements were subject to noise and the shift lever positions obtained only from the rotational speed measurements were subject to a time drift. Sensor Fusion combines data, more specifically the absolute angle and the relative angle, to provide robust absolute angle results.

The ultimately engaged gear can then with the gear detection sensor 85 delivered, geared in the gear actually be compared. In the case of a difference, for example, the (possibly inverse) Le Mans effect may be present, in which the motor vehicle would roll in the opposite direction as intended by the driver.

The course of the shift lever 30 in the H-circuit diagram (or other circuit diagram) can be determined by means of a number of a few momentary positions of the shift lever and based on it to predict the gear that the driver will insert. For this purpose, known algorithms such as a neural network are used.

As can be seen from the foregoing, a MEMS sensor can be used to detect three translatory and two or three rotational directions of motion for detecting the engaged or predicted engaged gear, the Le Mans effect, or the inverse Le Mans effect in a manual transmission.

LIST OF REFERENCE NUMBERS

5

motor vehicle

10

engine

15

crankshaft

20

transmission

25

external switching operation

27

first sensor / MEMS sensor

30

gear lever

35

knob

40

shift cable

45

Wählkabel

50

internal switching operation

55

shift shaft

60

Pin code

65

Pin code

70

second sensor / MEMS sensor

75

switching mass

80

vibration absorber

85

Transition detection sensor

90 '

data line

90 "

data line

90 ''

data line

95

microcontroller

Claims (11)

Motor vehicle (5) with an external switching operation (25) for engaging gears of a manual transmission (20), an internal switching operation (50) partly for projecting into the transmission for shifting the gears, a first sensor (27) mounted in the body and one in the Kinematikkette between external switching operation (25) and internal switching operation mounted second sensor (70), wherein the first sensor (27) and the second sensor (70) each have a MEMS sensor for detecting translational accelerations in three mutually different spatial directions and for detecting rotational speeds in or include two or three different directions of rotation. Motor vehicle after Claim 1 in which the second sensor is attached to or in an axially and / or rotationally movable part (30, 35) of the external shifting operation, in particular a shift lever (30) or a shift knob (35). Motor vehicle after Claim 1 in which the second sensor is attached to or in an axially and / or rotatable part of the internal shifting mechanism or a shift linkage. Motor vehicle according to one of Claims 1 to 3 wherein the first and second sensors are configured to provide data in real time during gear selection. Motor vehicle after Claim 4 comprising a microcontroller (95) arranged to first determine current positions of the shift lever during gear selection with the data, and based thereon to predict the gear the driver will engage. Motor vehicle after Claim 5 in which the microcontroller is set up to adjust the rotational speed of the crankshaft (15) to the rotational speed of the transmission input shaft during gear selection as a function of the predicted gear. Motor vehicle after Claim 5 or 6 in that the transmission has a gear recognition sensor (85) for detecting the geared gear and the microcontroller (95) is adapted to determine whether the predicted gear or the engaged gear on the one hand and the shifted gear on the other hand differ. Motor vehicle after Claim 7 in which the microcontroller is set up, in the event that the predicted or engaged gear, on the one hand, and the shifted gear, on the other hand, issue a visual or audible warning or an acceleration of the motor vehicle at least at least. Motor vehicle after Claim 5 operable in a sailing mode and in which the microcontroller is arranged to determine the gear suitable for the current driving conditions at the driver's side initiated leaving the sailing mode and to output a visual or audible warning in the event of a difference from the predicted gear. Use of a MEMS sensor for detecting three translational and two or three rotational movement directions for the gear recognition in a motor vehicle with a manual transmission. Use of a MEMS sensor for detecting three translational and two or three rotational directions of movement for detection the Le Mans effect or the inverse Le Mans effect in a manual transmission.

Images