FR2782481A1 - Detecting rolling direction of motor vehicle involves deciding whether engine and gearbox are rotating in same/opposite directions from their behavior when coupling torque increases - Google Patents

Abstract

The method involves using revolution rate sensors generating signals representing the engine (nM) and gearbox (nG) revolution rates and feeding them to an evaluation unit. A decision is made as to whether the engine and gearbox are rotating in the same or opposite directions according to the behavior of the engine and gearbox speeds when the coupling torque increases if the speeds change in predefined manners. An Independent claim is also included for an arrangement for detecting the rolling direction of a motor vehicle.

Description

The invention relates to a method and an identification device

  of the running direction of a motor vehicle comprising a clutch arranged in the control train with a motor and a gearbox, driven wheels being connected to the gearbox downstream of which they are arranged, speed sensors of rotation which are provided generating signals representing the rotational speeds of the motor and the gearbox and sending these signals which at least represent the particular speeds of rotation to a stripping module. It is necessary to identify the direction of rotation of a motor vehicle for carrying out safety strategies, for example a protection against the stalling of the engine of the vehicle when the

  Clutch and shift systems are automated.

  However, the sensors usually used for the determination of

  rotational speeds are not able to identify the directions of rotation.

  The object of the present invention is therefore to create a method and a device by means of which the variation of the rotational speed signals of the engine and of the gearbox makes it possible to determine the direction in which

  which a motor vehicle rolls.

  According to an essential feature of the method of the invention, the variation of the rotational speeds of the engine and the gearbox in the presence of an increase in the clutch torque makes it possible to conclude that the engine and the gearbox rotate in the direction of rotation. same direction or in opposite directions when the speed of rotation of the gearbox and that of the motor vary

in predetermined ways.

  An essential advantage of the present invention lies in the fact that the direction in which the vehicle rolls can be identified by simple stripping of the rotational speeds of the engine and the gearbox according to determined criteria without costly solutions. pressing equipment are necessary, for example require sensors offset from each other. Identification errors

are advantageously avoided.

  Another essential advantage lies in the fact that the device of the invention makes it possible to obtain that, when the gearbox actually turns in the opposite direction to that of the engine, a flag is raised and the remainder until the vehicle is parked or the reverse rotation of the engine and gearbox is eliminated

after identification of the defect.

  The invention will be described in more detail by way of non-limiting example with reference to the accompanying drawings, in which: FIG. 1 is a diagram of an arrangement consisting of an engine, a friction clutch, a a gearbox and driven wheels of a motor vehicle; and Figures 2 to 6 are graphs illustrating to explain the invention the relationship between the rotational speeds of the engine and the gearbox and the clutch torque as a function of time during

  start or start of the ride.

  In Figure 1, the motor of a motor vehicle is designated 1. A friction clutch 3 is disposed between the engine 1 and a gearbox 2. The latter is connected to the driven wheels 4. A rotational speed sensor is associated with the output shaft 11 of the engine 1. A speed sensor 6 is associated with the input shaft 21 of the gearbox 2. The output signals of the sensors 5 and 6 are sent to a

stripping module 7.

  The manner of determining whether the directions of rotation identified by the speed sensors 5 and 6 are the same or are reversed during a start or the beginning of a journey of a motor vehicle goes all

  first be described with reference to Figures 2 and 3.

  In any case, at time t = to (initial state), the speed nG of the gearbox is> 0, the rotation speed nM of the motor is> 0 and the speed of rotation nG of the gearbox at speeds is

  less than that, nM, of the motor.

  When then the clutch torque MK is elevated in the time interval from 0 to 1, the speed of the engine drops and that of the gearbox rises when the engine 1 and the gearbox 2

  turn in the same direction, as shown in Figure 2.

  This means that it is possible to conclude that the engine i and the gearbox 2 rotate in the same direction according to the conditions InGl> O, IlnM1> O and InGl <lnMlI (and by the fact that the speed of rotation nG of the gearbox

  rises (state: O) when the clutch torque MK is increased.

  When, under the same conditions, the engine i and the gearbox 2 rotate in opposite directions (see nG real in Figure 3), the speeds of rotation nG of the gearbox and nM of the engine fall according to

  Figure 3 when increasing the clutch torque MK.

  This means that it is possible to conclude that the engine 1 and the gearbox 2 rotate in opposite directions according to the conditions InG1> 0, InM1> O and InGI <InMI () and that the speed rotation nG of the gearbox, which is determined by the sensor 6, fall (state: C) during a

  increase of the clutch torque MK.

  The identification of the rolling direction at the beginning of a path, for example on a downward slope, with a clutch

  following, will be explained with reference to Figures 4 and 5.

  It is further accepted initially that at time t = to, the rotation speed nG of the gearbox is> 0 and that, nM, of the engine 1 is> 0 and that otherwise it results from the rotation that the speed of rotation nG

  of the gearbox 2 is greater than that, nM of the engine 1.

  When then the clutch torque MK is elevated during the time interval between t0 and t1, it can occur according to Figure 4 that the speed of the motor 1 rises and more than the speed of the box 2 drops when the motor 1 and the box 2 turn in the same

meaning.

  This means that it is possible to conclude that the engine 1 and the gearbox 2 rotate in the same direction according to the conditions InG1> OInM1> O and InG1> lnM1 and that the speed nM of the engine monte (state:) in

  presence of an increase in the clutch torque MK.

  When, on the other hand, under the same initial conditions and as shown in FIG. 5, during an increase in the clutch torque MK in the time interval between to and t1, the speed nM of the engine 1 drops and simultaneously the speed nG of the gearbox also falls sharply (state:), this means that the engine i and the gearbox 2

  turn in opposite directions (see real nG in Figure 5).

  In other words, it can be concluded that the engine 1 and the gearbox 2 rotate in opposite directions according to the conditions InG1> O, InM1> 0 and InG1> 1nM1 and that the speed nM of engine falls when increasing MK clutch torque. This is incidentally explained when an increase in engine torque occurs simultaneously. This is regularly the case in the presence of opposite directions of rotation of the engine and the gearbox or the entry and the exit of the clutch, because the regulator of idling of the vehicle tries to

  oppose a fall in the rotational speed of the motor.

  The stripping module 7 can easily identify from the values of the rotational speeds obtained from the sensors 5 and 6, during an increase in the clutch torque MK, even without additional expense in detectors, equipment, etc., if the gearbox 2 and the engine 1 turn in the same direction or in opposite directions during a start of tracking or during a start and during a ride, for example on a hill. It suffices for this purpose that the stripping module 7 identifies in the manner described how the speed of rotation of the gearbox nG and the speed of rotation of the motor nM vary during a

  increase of the clutch torque MK under the conditions mentioned.

  When the rotational speed signals emitted by the sensors 5 and 6 make it possible to identify that the gearbox 2 and the engine 1 are rotating in opposite directions, the stripping module 7 raises a bistable flag which indicates to the control electronics that the motor 1 and the gearbox 2 rotate in opposite directions, so that this electronics can take corresponding measures. The flag is held up as long as engine 1 and gearbox 2 rotate in opposite directions. It is only lowered when engine 1 and gearbox 2 stop rotating in opposite directions and there is a situation in

  which this can also be identified, for example when the vehicle is stopped.

  It is furthermore particularly advantageous to ensure that identification errors to be attributed to the fact that it is possible that normal walking conditions which can appear briefly simulate the state mentioned above are excluded. This can be for example the case during a shift and will be explained next to

Figure 6.

  For example, the condition may appear briefly when going from the 2nd to the speed and when the first speed has been passed, when increasing the clutch torque. For this reason, the flag mentioned, which indicates that the engine 1 and the gearbox 2 rotate in opposite directions, is raised only when at least a predetermined time, for example at least 1 second or at most 1 second. a second, has passed during the passage of the speed. As a variant, a time that has elapsed since the last speed was released is another advantageous condition.

of time for the raising of the flag.

  In order to better exclude identification errors, it is required that, at the conditions 3, the rotational speed of the box be greater than a prescribed value, for example of 100 rpm, at the speed of rotation of the motor (nG> nM + 100) and moreover that the clutch torque exceeds a value

prescribed, for example,> 10 Nm.

  Another advantageous measure is to raise the flag only when the engine torque is positive, which should not be

  imperatively the case, during the described passage of speed.

  In summary, the conditions described above for a lack of identification error in that the gearbox and the engine rotate in opposite directions are therefore: (nG> nM + 100) and (MK> 10 Nm) and ( nM fall) and (more than one prescribed time elapses during the passage of speed) The fall of the speed of rotation of the engine nM under these conditions is not plausible under normal conditions and shows unequivocally that the box at speeds 2 actually turns in the opposite direction of

that of the engine 1.

  The lowering of the flag takes place advantageously under the following conditions:

(nM> nG + 100 or nG <100).

  This means that a flag raised at the end of an identification having been carried out once only remains lifted until the vehicle is stopped or until the engine is still running faster than the gearbox, which can only occur in the case of a previous identification error. The mentioned conditions of raising the flag may be present only briefly, it is necessary that the flag be maintained

until you return to the initial state.

  It is necessary to prevent an inadvertent start of tracking in reverse, especially with diesel engines. This situation may occur when the vehicle is traveling in reverse when the engine is stopped or stalled and a forward gear has been passed. Therefore, when the flag has been raised, the beginning of tracking is prevented or it takes place only with a sufficiently small torque, for example of 20 Nm, so that the

engine does not turn upside down.

  When rolling in reverse occurs while a

  forward speed has passed, a fast clutch can stall the engine.

  So when the flag is up, the clutch can only be done with

  a limited torque, for example at most 30 Nm.

  The invention is not limited to the fact that the clutch is arranged between the engine and the gearbox. It can also be arranged for example on the output side downstream of the gearbox. In general, the rotational speed of the motor can be switched with the clutch input rotational speed and the rotational speed of the gearbox can be switched with the output speed of the clutch. The clutch input rotational speed is accordingly a rotation speed which represents at least that of this input element. The output speed of rotation of the clutch is consequently a speed of

  rotation which represents at least that of this output element.

  It goes without saying that various modifications can be made to the

  system described and shown without departing from the scope of the invention.

Claims (14)

  1. A method of identifying the rolling direction of a motor vehicle comprising a clutch arranged with a motor and a gearbox in the drive train, driven wheels being connected to the gearbox downstream of which they are arranged , sensors which are provided generating signals representing the rotational speeds of the motor and of the gearbox and sending the signals which at least represent the particular speeds of rotation to a stripping module, characterized in that the variation of the speeds of rotation of the engine and the gearbox concludes, in the presence of an increase in the clutch torque, that the engine and gearbox rotate in the same direction or in opposite directions when the speed of   rotation of the gearbox and that of the motor vary in predetermined ways.   2. Method according to claim 1, characterized in that it is concluded that the gearbox and the engine rotate in opposite directions when, during an increase in the clutch torque and from the state InGl > 0, InM1> 0 and InG1 <lnMI, both the speed of the motor and that of the gearbox are falling.   3. Method according to either of claims 1 and 2,   characterized in that it is concluded that the gearbox and the engine rotate in the same direction when, in the presence of an increase of the clutch torque and from the state InG1> 0, InM1> 0   and InG l <lnMi, the speed of the gearbox rises and the engine speed drops.   4. Method according to claim 1, characterized in that it is concluded that the gearbox and the engine rotate in opposite directions when, during an increase in the clutch torque and from InGl> 0, InMl> 0 and InGl> lnMI, the speed of the gearbox and the engine speed drop.   5. Method according to either of claims 1 and 3,   characterized in that it is concluded that the motor and the gearbox rotate in the same direction when, in the presence of an increase of the clutch torque and from the state InGI> O, InMI> 0   and InGl> lnMI, the gearbox speed drops and the engine speed rises.   6. Process according to any one of claims 1 to 5,   characterized in that, in determining, in the stripping electronics, that the gearbox and the motor rotate in opposite directions, a flag displaying the opposite directions of rotation is raised when at least a predetermined time s has elapsed following the last gear switch.   7. Method according to claim 6, characterized in that the time prescribed is at least 1 second.   8. Method according to claim 6, characterized in that the time   prescribed is at most 1 second.   9. Process according to any one of claims 6, 7 and 8,   characterized in that the flag displaying the reverse directions of rotation is raised when: (nG> nM + 100) and (MK> 10 Nm) and (more than the predetermined time has elapsed since the start of the shift); and (the   engine rotation speed drops).   10. Process according to any one of claims 1-5,   characterized in that a flag displaying the opposite directions of rotation is raised when the torque transmitted by the motor is still greater than one predetermined positive threshold.   11. The method of claim 10, characterized in that the predetermined threshold of the engine torque is in a range of between 0 and 30 Nm.   12. A method according to any one of the preceding claims,   characterized in that an identified flag remains raised until the vehicle is stopped or the engine is running faster than the gearbox.   13. Process according to any one of the preceding claims,   characterized in that the flag is lowered when (nM> nG + 100) or (nG <100).   14. Device for identifying the rolling direction of a motor vehicle comprising a clutch arranged with a motor and a gearbox in the drive train, driven wheels being connected to the gearbox downstream of which they are arranged rotational speed sensors which are provided generating signals representing the rotational speeds of the motor and of the gearbox and sending the signals representing at least the particular speeds of rotation to a stripping module, characterized in that the variation of the speeds rotation of the engine and the gearbox during an increase in the clutch torque5 makes it possible to conclude that the engine and the gearbox rotate in the same direction or in opposite directions when the speed of the   box and that of the engine vary in predetermined ways.