Hybrid drivetrain for a hybrid-driven vehicle and method for same

Abstract

A hybrid drivetrain for a hybrid-driven vehicle, having an internal combustion engine which outputs to vehicle wheels via a load path, in which a dual-mass flywheel is connected, which has flywheel masses elastically coupled via spring assemblies, and at least one electric machine, which can be coupled with respect to drive into the load path via an automatic transmission, wherein a drive torque (MBKM) from the internal combustion engine and a drive torque (MEM) from the electric machine can be added together with power addition in the automatic transmission to form a total drive torque, using which the vehicle wheels are drivable, and wherein an electronic control unit, on the basis of driving mode parameters and/or a driver intention, controls and engine controller of the internal combustion engine and/or power electronics of the electric machine using target torque specifications.

Claims

1. A hybrid drivetrain for a hybrid-driven vehicle, comprising: an internal combustion engine which outputs to vehicle wheels via a load path, in which a dual-mass flywheel is connected, which has flywheel masses elastically coupled via spring assemblies, and an electric machine, which can be coupled with respect to drive into the load path via an automatic transmission, wherein a drive torque from the internal combustion engine and a drive torque from the electric machine can be added together with power addition in the automatic transmission to form a total drive torque, by which the vehicle wheels are drivable, and wherein an electronic control unit, on the basis of driving mode parameters and a driver intention, activates an engine controller of the internal combustion engine and/or power electronics of the electric machine using target torque specifications, and wherein the drivetrain has an evaluation unit, which recognizes the presence of a DMF jam causing increased rotational irregularity, in which the spring assemblies of the dual-mass flywheel are jammed in the compressed state, and the evaluation unit generates an engine intervention signal upon the presence of a DMF jam, by which the engine controller controls the internal combustion engine using a torque surge to release the DMF jam, wherein the evaluation unit is associated with a compensation unit, which generates a compensation signal on the basis of the torque surge, by means of which the electric machine is activatable using a compensation torque, which compensates for the torque surge.

2. The hybrid drivetrain as claimed in claim 1, wherein the compensation torque from the electric machine counteracts the torque surge from the internal combustion engine in such a way that the torque surge remains without influence on the total output torque output on the vehicle wheels, i.e., the torque surge takes place in a power-neutral manner.

3. The hybrid drivetrain as claimed in claim 1, wherein the torque surge initiated by the evaluation unit is a sudden, short-term torque increase and the counteracting compensation torque is a sudden, short-term torque reduction.

4. The hybrid drivetrain as claimed in claim 1, wherein the torque surge initiated by the evaluation unit is a sudden, short-term torque reduction and the counteracting compensation torque is a sudden, short-term torque increase.

5. The hybrid drivetrain as claimed in claim 2, wherein the torque surge initiated by the evaluation unit is a sudden, short-term torque increase and the counteracting compensation torque is a sudden, short-term torque reduction.

6. The hybrid drivetrain as claimed in claim 2, wherein the torque surge initiated by the evaluation unit is a sudden, short-term torque reduction and the counteracting compensation torque is a sudden, short-term torque increase.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the figures:

(2) FIG. 1 shows a rough schematic block diagram of a hybrid drivetrain of a hybrid-driven motor vehicle; and

(3) FIG. 2 shows a further block diagram of interconnected program components of an electronic control unit for implementing the invention.

DETAILED DESCRIPTION

(4) A hybrid drivetrain shown in FIG. 1 has an internal combustion engine 1, an automatic transmission 3, and an electric machine 5. The internal combustion engine 1 is connected via an internal combustion engine shaft 7 to an internal-combustion-engine-side flywheel mass 9 of a dual-mass flywheel 11. Its transmission-side flywheel mass 13 is connected to a transmission input shaft 15 of the automatic transmission 3. Viewed in the circumferential direction, spring assemblies (not shown) act between the flywheel masses 9, 13. The automatic transmission 3 has an indicated spur gear step St1 on the output side, which has a drive connection to an axle differential 15 of a vehicle axle of the motor vehicle, whereby a load path results, via which a drive torque M.sub.BKM from the internal combustion engine can be output to the vehicle axis. Moreover, the electric machine 5 has a drive connection via an electric machine shaft 17 and via a second spur gear step St2 to the automatic transmission 3.

(5) In the automatic transmission 3, depending on the set driving mode, the drive torque MEM generated by the electric machine 5 and the drive torque M.sub.BKM generated by the internal combustion engine 1 can be added up with power addition to form a total drive torque M.sub.total, using which the vehicle axle is drivable. In contrast, in a startup procedure, the electric machine can act as a starter, using which a starting torque is transferred to the internal combustion engine 1. In this case, the internal combustion engine 1 is accelerated out of the standstill by the electric machine 5 at very high speed gradients to the target speeds. This can result in a DMF jam of the dual-mass flywheel 11 located in the hybrid drivetrain.

(6) The hybrid drivetrain shown in FIG. 1 furthermore has an electronic control unit 19, which, on the basis of driving mode parameters and a driver intention, activates an engine controller 21 of the internal combustion engine 1 and power electronics 23 of the electric machine 5 using target torque specifications and/or activates a transmission controller 25 of the automatic transmission 3 using shift signals for the gear shifting. FIG. 1 and FIG. 2 are produced with regard to simple comprehension of the invention. Therefore, the two figures are merely rough simplified illustrations, which do not reflect a realistic structure of the hybrid drivetrain or a realistic software architecture of the control unit 19 and the controllers 21, 23, 25.

(7) The program components essential for the invention, by means of which the invention is implementable, are shown in FIG. 2. Accordingly, the electronic control unit 19 has a DMF evaluation unit 27, which detects whether a DMF jam exists or not. Such a DMF jam results in increased rotational irregularity, which is disadvantageous with regard to smooth-running behavior of the hybrid drivetrain. The DMF evaluation unit 27 is connected on the input side to a speed sensor 29, which detects an actual speed n.sub.actual in the hybrid drivetrain. In a processing unit 31 connected downstream with respect to signals, a noisy running signal S.sub.L, which is applied to the signal input of the DMF evaluation unit 27, is computed from the actual speed n.sub.actual.

(8) Moreover, a lambda signal λ generated by a lambda regulator 33 is applied to the signal input of the DMF evaluation unit 27. By way of a comparison of the lambda signal λ to the noisy running signal S.sub.L, a judgment is performed in the DMF evaluation unit 27 as to whether a DMF jam exists on the basis of these two parameters in the current operating situation.

(9) If such a DMF jam, which causes increased rotational irregularity, is present, the DMF evaluation unit 27 generates an engine engagement signal S.sub.M, using which the engine controller 21 activates the internal combustion engine 1 using a torque surge to release the DMF jam.

(10) As is furthermore apparent from FIG. 2, the DMF evaluation unit 27 has a signal connection at a signal output to a compensation unit 35. In the compensation unit 35, a compensation signal is generated on the basis of the torque engagement signal S.sub.M, using which the power electronics 23 activates the electric machine 5 using a compensation torque M.sub.A, which compensates for the torque surge or counteracts it.

(11) In this case, the compensation torque M.sub.A from the electric machine counteracts the torque surge from the internal combustion engine in such a way that the torque surge remains without influence on the total output torque M.sub.total output to the vehicle wheels, whereby the torque surge takes place in a power-neutral manner, so that vehicle accelerations unpleasant to the driver do not occur due to the torque surge.

(12) The above-mentioned DMF evaluation unit 27 for recognizing a DMF jam can be integrated into a misfire recognition function, as described in DE 10 2015 221 670 A1. Therefore, reference is expressly made to this document.