KR102589561B1 - Validation method of torque profile to determine contact point of hybrid clutch in hybrid vehicle powertrain - Google Patents

Abstract

The present invention relates to a method for testing the validity of a torque profile for determining the contact point of a hybrid clutch in the powertrain of a hybrid vehicle. In this case, in the powertrain 1, the electric motor 3 is connected to the internal combustion engine by the hybrid clutch 4. It can be engaged with the engine 2, and when the hybrid clutch 4 moves from the open state to the closed state for adaptation of the contact point, tow-starting of the stationary internal combustion engine 2 The torque profile of the belt starter generator 11 provided for is evaluated for adaptation of the contact points. In a method that allows for a particularly accurate validation of the torque profile of the belt starter generator, the torque profile of the belt starter generator 11 used for contact point adaptation is validated by means of the torque profile of the electric motor 3.

Description

Validation method of torque profile to determine contact point of hybrid clutch in hybrid vehicle powertrain

The present invention relates to a method for testing the validity of a torque profile for determining the contact point of a hybrid clutch in the powertrain of a hybrid vehicle. In this case, in the powertrain, the electric motor can be coupled to the internal combustion engine by the hybrid clutch, and the hybrid clutch When moving from the open state to the locked state for adaptation of the contact point, the torque profile of the belt starter generator provided for tow-starting of a stationary internal combustion engine is evaluated for adaptation of the contact point.

DE 10 2008 030 473 A1 describes a hybrid device in which the clutch is engaged gradually and the effect of the engaged clutch on an electric machine rotating at a preset speed is evaluated, thereby determining the contact point of the clutch on a stationary internal combustion engine. Methods are known for determining the contact point of an automated clutch in a powertrain.

As such, the strategy for determining the point of contact involves slowly engaging the clutch while observing the torque signal. The hybrid clutch, as known from DE 10 2014 207 720 A1, with a special assembly arrangement of a belt starter generator for starting the internal combustion engine and with a propulsive electric machine on the output side of the hybrid clutch and on the transmission behind it, also provides The belt starter generator also makes it possible to use it as a torque source for contact point adaptation. In this case, starting of the internal combustion engine is performed via the belt starter generator while the clutch is engaged.

A disadvantage of the prior art as described above is that the belt drive device of the belt starter generator has a certain elasticity that causes a situation where the torque of the belt starter generator is exposed to fluctuations due to vibration formation between the relevant components. It is. Accordingly, the torque of the belt starter generator, which becomes systematically more accurate through higher rotational speeds, may be distorted by vibration that appears intermittently and with different characteristics depending on the driving situation. Distorted torque can cause erroneous contact point adaptation.

The object of the present invention is to provide a method for checking the plausibility of the torque profile of a belt starter generator, by which the influence of vibrations on the torque profile of the belt starter generator can be detected upon adaptation of the contact points.

According to the invention, the above problem is solved by ensuring that the torque profile of the belt starter generator used for contact point adaptation is checked for plausibility by the torque profile of the electric motor. Since the electric motor is connected to the hybrid clutch, the electric motor also experiences torque changes when the clutch is engaged. Therefore, the torque profile of the electric motor can be used to balance the torque profile of the belt starter generator, whereby contact point adaptation is ensured by the belt starter generator. For further observation, the torque signal is converted to torque at the clutch via a belt transmission.

Preferably, the plausibility check is carried out during pure electric operation of the hybrid vehicle, when the torque profile of the belt starter generator and the torque profile of the electric motor are almost simultaneous, so that the correct contact point adaptation is deduced. If this is the case, it can be assumed that no vibrations act on the belt starter generator and therefore that there are no torque fluctuations affecting the contact point adaptation.

In one embodiment, when the electric motor rotates at a controlled speed and the belt starter generator passively traction starts the internal combustion engine at a controlled speed, the validity of the torque profile of the belt starter generator is determined by the torque profile of the electric motor. Inspection is carried out. Since not only the electric motor but also the belt starter generator operates at a preset speed, torque changes can simply be detected when the contact point of the hybrid clutch is reached. However, it should be noted that when the internal combustion engine is traction-started by a belt starter generator, the internal combustion engine is still passive and does not have inherent ignition characteristics.

In one refinement, a clutch target torque is applied to the hybrid clutch for contact point adaptation, and the torque profile at the rotating belt starter generator and the torque profile at the rotating electric motor are compared for torque changes. Only if the torque profiles of the belt starter generator and the electric motor have torque changes at approximately the same time can it be assumed that the hybrid clutch reaches the point of contact and initiates transmission of the clutch torque. If significant torque fluctuations appear only in the torque profile of the belt starter generator, a distortion of the torque profile of the belt starter generator due to vibration can be inferred.

In one variant, the offset of the belt starter generator and the offset of the electric motor are determined separately from each other, in which case the individual torque profiles are corrected by the relevant offsets determined. After these measures, it can be assumed that the absolute values of the torque profiles of the belt starter generator and the electric motor have similar profiles.

In order to be able to perform a sufficient comparison between the torque of the belt starter generator and the torque of the electric motor, after offset correction, the torque profile of the belt starter generator is adapted to the torque profile of the electric motor.

In one embodiment, if the absolute value of the belt starter generator torque is less than the absolute value of the electric motor torque, the torque profile of the belt starter generator is adapted to the torque profile of the electric motor. This dynamic balance eliminates the offset from the torque of the belt starter generator.

In one alternative, when the absolute value of the belt starter generator torque is greater than the absolute value of the electric motor torque, the torque profile of the belt starter generator is adapted to the torque profile of the electric motor. In this case, a certain offset is dynamically applied to the torque of the belt starter generator.

In one refinement, a plausibility check is made when the powertrain behind the hybrid clutch is opened. This ensures that the torque influence that can act against the hybrid clutch by the powertrain of the hybrid vehicle placed behind is stopped, and consequently a sufficiently accurate plausibility check is possible between the torque profiles of the belt starter generator and the electric motor.

In one embodiment, if the plausibility check fails, the contact point adaptation takes place from a linear weighting, preferably averaging, of the belt starter generator torque and the electric motor torque. Accordingly, even in this case, the position of the hybrid clutch that starts transmitting clutch torque can be confirmed. This position is hereinafter referred to as the contact point.

The invention allows for a number of embodiments. One of these embodiments is described in more detail with reference to the drawings shown in the drawing section.
Figure 1 shows a schematic diagram of a hybrid drive with a belt starter generator.

In Figure 1, a schematic diagram of the powertrain 1 of a hybrid vehicle is shown. The powertrain (1) includes an internal combustion engine (2) and an electric motor (3). A hybrid clutch (4) is arranged immediately behind the internal combustion engine (2) between the internal combustion engine (2) and the electric motor (3). The internal combustion engine 2 and the hybrid clutch 4 are connected to each other through the crankshaft 5. The electric motor 3 has a rotatable rotor 6 and a fixed stator 7. The output shaft 8 of the hybrid clutch 4 comprises a coupling element not shown in detail in the drawing, for example a second clutch or torque converter arranged between the electric motor 3 and the transmission 9. It is connected to the transmission (9). The transmission 9 transmits torque generated by the internal combustion engine 2 and the electric motor 3 to the driving wheel 10 of the hybrid vehicle.

To start the internal combustion engine (2) using the torque generated by the electric motor (3) while the hybrid vehicle is running, or to drive by the internal combustion engine (2) and electric motor (3) running during boost operation, the internal combustion engine ( The hybrid clutch 4 arranged between 2) and the electric motor 3 is engaged. In the present case, the internal combustion engine 2 is started by a belt starter generator 11 positioned on the internal combustion engine.

In order to ensure that during starting of the internal combustion engine 2, sufficient torque is provided to move the vehicle without loss of comfort through the drive wheels 10 and at the same time to actually start the internal combustion engine 2, the clutch characteristics of the hybrid clutch 4 Accurate information about the curve is needed. This clutch characteristic curve is adapted from fulcrums where the contact points of the hybrid clutch 4 are of decisive significance. The contact points are determined once for the operation of the powertrain and are adapted during operation to changed clutch characteristics, which are not constant due to various influencing factors, such as wear, readjustment and temperature of the hybrid clutch 4 and aging processes. Hereinafter, the contact point is understood as a position of the hybrid clutch 4 where the friction surfaces of the input or output portion of the hybrid clutch 4 come into frictional contact with each other.

To adapt the contact point, in the electric driving mode of the powertrain 1 the hybrid clutch 4 is gradually moved from the open state to the engaged state. At the same time, the belt starter generator 11 traction-starts the passive internal combustion engine 2 at a preset constant rotation speed. In order to determine the contact point, by engaging the hybrid clutch 4, the clutch target torque applied to the hybrid clutch 4 gradually increases, so that the torque that can be assigned to the clutch target torque in the belt starter generator 11 It expands until it can be detected. In this case, the belt starter generator 11 is in a speed-controlled operating state, that is, in a stable speed state. To determine the contact point, the hybrid clutch 4 is configured so that the friction engagement surfaces of the input and output parts of the hybrid clutch 4 are in frictional contact, and the minimum torque detected by the corresponding reaction of the belt starter generator 11 is the belt starter generator 11. It is driven until it is transmitted to the generator (11). The corresponding response is a defined torque increase in the torque profile of the belt starter generator 11.

Since the belt starter generator 11 has a belt drive device configured to be elastic, torque fluctuations may occur because of the elastic configuration of the belt drive device and thus between the relevant components of the powertrain 1. This is because vibration may occur. Such vibrations cause torque changes of a magnitude similar to those caused by contact point adaptation. In order to be able to reliably assign the torque changes to the contact point adaptation, for plausibility checks the torque profile of the electric motor 3 in operation is observed, parallel to the torque profile of the belt starter generator 11 . In the torque profile of the electric motor 3, an increase in torque is also observed when the contact point is reached by the hybrid clutch 4. The belt starter generator 11 and the electric motor run when the electric motor 3 rotates in a speed-controlled state and the belt starter generator 11 passively traction starts the internal combustion engine 2 in a speed-controlled state as well. By comparing the torque profiles of (3), confidence in the contact point adaptation carried out by the belt starter generator (11) increases. In this comparison process, the fact that the internal combustion engine 2 rotates faster than the electric motor 3 must be taken into account.

However, before comparing the torque profiles of the belt starter generator 11 and the electric motor 3, the condition must be ensured that not only the torque profile of the belt starter generator 11 but also the torque profile of the electric motor 3 is offset-corrected. Therefore, individual offsets are determined separately from each other not only for the belt starter generator 11 but also for the electric motor 3, and the torque profile of the belt starter generator 11 and the torque profile of the electric motor 3 are determined by the individual offsets. It is erased as much as Afterwards, the erased torque profiles have similar profiles.

There are two cases in which the torque profile of the belt starter generator (11) can be adapted to the torque profile of the electric motor (3). In the first case, the absolute value of the torque of the belt starter generator 11 is smaller than the absolute value of the torque of the electric motor 3. In this case, the offset of the belt starter generator 11 is added to its own torque, so that the torque of the belt starter generator 11 can be expanded by the torque of the electric motor 3.

However, if the absolute value of the torque of the belt starter generator 11 is greater than the absolute value of the torque of the electric motor 3, the offset of the belt starter generator 11 is canceled from itself, so that the torque of the electric motor causes the belt starter generator 11 to The torque may be reduced. The adaptation of the torque of the belt starter generator 11 takes place only gradually and only after several operations. In other words, the relatively smaller torque of the belt starter generator 11 is determined several times. Only then is the operation of the torque of the belt starter generator 11 performed.

However, in one alternative, if the plausibility check of the torque profile of the belt starter generator 11 with the torque of the electric motor 3 fails, the contact point adaptation may be rejected.

However, in another variant, a linear weighting of the observed torque profiles of the belt starter generator 11 and the electric motor 3 can also be implemented for contact point adaptation. In the simplest case, an average value is determined from the two torque signals and this average value is later used to determine the contact point.

The feasibility test of the torque profile for contact point adaptation is that the rear powertrain (1) connected behind the hybrid clutch (4) is open, and as a result, no influence can be transmitted from the rear powertrain to the hybrid clutch. It is executed only if it does not exist. Alternatively to the open powertrain (1), the plausibility check can also be made in overrun or acceleration operation of the electric motor (3). In this case, it must be ensured that the torque increase or torque decrease actually reflects the torque influence through the hybrid clutch 4, but not the torque influence within this powertrain 1. A situation like this is possible in the case of creeping vehicles on the road, where the point of contact is adapted to low torque at constant speed without the need for fuel.

1: Powertrain
2: Internal combustion engine
3: electric motor
4: Hybrid clutch
5: Crankshaft
6: rotor
7: Stater
8: output axis
9: gearbox
10: driving wheel
11: Belt starter generator

Claims (10)

This is a validity test method of the torque profile to determine the contact point of the hybrid clutch in the powertrain of a hybrid vehicle, and the electric motor (3) within the powertrain (1) can be combined with the internal combustion engine (2) by the hybrid clutch (4). In the case where the hybrid clutch 4 moves from the open state to the closed state for adaptation of the contact point, the torque profile of the belt starter generator 11 provided for traction starting of the stationary internal combustion engine 2 changes. In a method for checking the validity of a torque profile evaluated for adaptation of the contact point,
A method for checking the validity of a torque profile, characterized in that the torque profile of the belt starter generator (11) used for contact point adaptation is checked for validity by the torque profile of the electric motor (3). 2. The method according to claim 1, wherein the plausibility test is carried out during purely electric operation of the hybrid vehicle, wherein the correct contact point adaptation is deduced when the torque profile of the belt starter generator (11) and the torque profile of the electric motor (3) proceed almost simultaneously. Method for checking validity of torque profile. The method according to claim 1 or 2, when the electric motor (3) rotates with the rotation speed adjusted and the belt starter generator (11) passively traction-starts the internal combustion engine (2) with the rotation speed adjusted. A method for checking the validity of a torque profile, characterized in that the validity of the torque profile of the belt starter generator (11) is checked based on the torque profile of the electric motor (3). 3. The method according to claim 1 or 2, wherein a clutch target torque is applied to the hybrid clutch (4) for contact point adaptation, a torque profile in the rotating belt starter generator (11) and a torque in the rotating electric motor (3). A method for checking the validity of a torque profile, characterized in that the profile is compared for torque changes. 3. The method according to claim 1 or 2, wherein the offset of the torque of the belt starter generator (11) and the offset of the electric motor (3) are determined separately from each other, and the individual torque profiles are corrected by the determined relative offsets. Method for checking validity of torque profile. 6. Method according to claim 5, characterized in that after offset correction, the torque profile of the belt starter generator (11) is adapted to the torque profile of the electric motor (3). The method of claim 6, wherein if the absolute value of the torque of the belt starter generator (11) is smaller than the absolute value of the torque of the electric motor (3), the torque profile of the belt starter generator (11) adapts to the torque profile of the electric motor (3). A method for checking the validity of a torque profile, characterized in that: The method of claim 6, wherein if the absolute value of the torque of the belt starter generator (11) is greater than the absolute value of the torque of the electric motor (3), the torque of the belt starter generator (11) is adapted to the torque of the electric motor (3). Method for checking validity of torque profile. 3. Method according to claim 1 or 2, characterized in that the plausibility check is carried out when the powertrain behind the hybrid clutch (4) is opened. 3. The method according to claim 1 or 2, characterized in that in case of failure of the plausibility check, the contact point adaptation is carried out from a linear weighting of the torque of the belt starter generator (11) and the torque of the electric motor (3), preferably from the formation of an average value. , Method for checking the validity of torque profile.

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