DE102021103250A1 - Device for reducing vibration excitations in a drive train of a hybrid vehicle - Google Patents

Abstract

The invention is a device for reducing vibration excitations in a drive train of a hybrid vehicle with an internal combustion engine, with an electric machine and with at least one electronic drive control unit. The drive control device has a cylinder equalization controller and is designed in such a way that an input signal of the cylinder equalization controller is generated by superimposing a signal proportional to the measured crankshaft angular velocity with a signal proportional to the angular momentum of the electric machine.

Description

In the unpublished German patent application 10 2020 112 471.6 the applicant describes a device for reducing vibration excitations of an entire engine-transmission combination in a hybrid vehicle with an internal combustion engine and an electric machine, in which the electric machine is used for active vibration reduction.

In principle, cylinder equalization controllers for equalizing the cylinder pressure curves of internal combustion engines are known from the prior art.

The object of the present invention is to improve the equalization of the cylinder pressure curves in a hybrid vehicle.

This object is solved by the independent claims. Advantageous embodiments are described in particular in the dependent claims.

The basic idea of the invention includes the determination of the internal combustion engine excitation for selected orders on the basis of the crankshaft and the electric machine. What is particularly new is that the electric machine is also taken into account.

The invention is a device for reducing vibration excitations in the drive train (ie the crankshaft and the electric machine) of a hybrid vehicle with an internal combustion engine, with an electric machine and with at least one electronic drive control unit. The drive control unit has a cylinder equalization controller and is designed such that an input signal of the cylinder equalization controller is generated by superimposing a signal proportional to the measured crankshaft angular velocity with a signal proportional to the (preferably angle-synchronous) angular momentum of the electric machine. The angular momentum of the electric machine is determined, for example, using the angular speed of the electric machine and the torque of the electric machine. Electric machine torque need not necessarily be considered when the electric machine is not governed or is idle; because in this case the electric machine torque is very small or zero.

Instead of a single drive control unit, an electric machine control unit and an internal combustion engine control unit with a communication bus between the electric machine control unit and the internal combustion engine control unit are preferably provided. The electric machine control unit is designed in such a way that the signal proportional to the (preferably angle-synchronous instead of time-synchronous) angular momentum of the electric machine is converted from the time domain to the frequency domain or from the angle domain to the order domain (e.g. by means of Fourier transformation), in particular as a function of the electric machine rotor angle for selected Engine orders (e.g. 0.5, 1.0 and 1.5 for a 6-cylinder engine or 0.5 and 1.0 for a 4-cylinder engine or 0.5, 1.0, 1.5 and 2.0 for an 8-cylinder engine) with a clear reference to the internal mechanical angular reference point of the Electric machine is transformed and that of it only for the selected engine orders, the amplitudes and phases are output via the communication bus to the internal combustion engine control unit. If the signal is angle-synchronous, the Fourier transformation provides the desired order analysis more reliably than a time-synchronous signal, since the latter could be associated with extended scope of signal theory (e.g. avoidance of phase drift).

Furthermore, the internal combustion engine control unit is preferably designed in such a way that these amplitudes and phases sent to the internal combustion engine control unit via the communication bus are transformed back from the frequency domain to the time domain or from the order domain to the angular domain in order to map the signal proportional to the angular momentum of the electric machine. With knowledge of the amplitude and phase, optionally an equivalent form of representation (e.g. real and imaginary part), an inverse transformation towards an electric machine angular momentum signal synchronous with the crankshaft angle is realized.

The angular position (in the form of a constant angular offset) of the electric machine relative to the internal combustion engine, determined when the internal combustion engine is stationary or rotating slowly, can be taken into account.

• Ein Motorgetriebeverbund bei Hybridfahrzeugen unterscheidet sich konzeptionell hinsichtlich der Anordnung von Kurbelwelle, Drehmomentwandler, Wandlerkupplung und Elektromaschine. In unterschiedlichen Betriebszuständen beeinflusst das dynamischen Schwingverhalten dieses Antriebskonzeptes eines Hybridfahrzeuges die Regelgüte eines üblichen Zylindergleichstellungsreglers für Verbrennungsmotoren negativ. In Extremfällen führt die Rückwirkung zu einer Anfachung der Schwingung durch den Zylindergleichstellungsregler.

The invention is based on the following considerations:

• A motor-transmission system in hybrid vehicles differs conceptually with regard to the arrangement of the crankshaft, torque converter, converter clutch and electric motor. In different operating states, the dynamic vibration behavior of this drive concept of a hybrid vehicle negatively influences the control quality of a conventional cylinder equalization controller for internal combustion engines. In extreme cases, the reaction leads to an amplification of the vibration by the cylinder equalization controller.

Known cylinder equalization controllers use the crankshaft signal to establish "equalization" of each cylinder to achieve; ie the measured crankshaft signal is evaluated in order to detect undesired engine excitation torques which are caused due to an unequal combustion process of the individual cylinders (eg 0.5,1.0,1.5 engine orders for 6 cylinders). A cylinder-selective correction pattern is then determined with regard to the injection quantity (e.g. "increase injection quantity for cylinders 1 and 5") and the undesired oscillation is gradually compensated for by appropriate injection correction.

Since the crankshaft signal in future hybrid vehicle drives will be corrupted by the dynamic reaction of the oscillating system, the control strategy of a known cylinder equalization controller generally no longer works. The dynamic reaction of the drive train in the engine-transmission system in hybrid vehicles means that the crankshaft no longer moves in phase with the combustion engine excitation and the amplitude of the crankshaft vibration is scaled due to the combustion engine excitation. In general, a non-linear transfer behavior from combustion engine excitations to crankshaft vibrations must be assumed.

Incorrectly identified correction patterns for the combustion pressure curves result from the non-phase-synchronous crankshaft vibration behavior. Since the vibration behavior is conceptual, a hardware measure to solve the problem is impossible or at least uneconomical.

The core idea of the invention is the generation of a virtual signal, which is a direct image of the internal combustion engine excitation, especially in idle mode. The input signal proportional to the measured crankshaft signal (in particular crankshaft angular velocity) of a conventional cylinder equalization controller is replaced by a corrected input signal, the corrected input signal being generated by superimposing the signal proportional to the measured crankshaft angular velocity with a signal proportional to the angular momentum of the electric machine. The invention thus relates to an extension of the known cylinder equalization controller input signals.

Preferably, the signal proportional to the angular momentum of the electric machine is detected by measuring the angular velocity of the electric machine using a rotor position sensor. In addition, the integrated electric machine torque must be taken into account for a correct determination of the electric machine angular momentum. If it can be ensured that the electric machine torque always plays a subordinate role, then this proportion can be neglected.

Instead of using the electric machine angular momentum as an input signal, equivalent signals such as time derivatives or integrals of the electric machine angular momentum can also be used for this application.

Mathematical derivations prove that even with an extremely complex, non-linear drive train behavior due to the two-mass flywheel feedback, the feedback and correct calculation of the primary-side two-mass flywheel angular velocity (crankshaft), the secondary-side two-mass flywheel angular velocity (electric machine rotor) and the electric machine torque result in a corresponding signal correction without the use of detailed Dynamic models of the drive components made possible.

Since the internal combustion engine and the electric machine (which can be integrated in the transmission) preferably have their own control devices with a bus connection, the improved consideration of the comparatively slow bus connection is an advantageous development of the invention in addition to the expansion of the cylinder equalization controller input signals: It is therefore further proposed according to the invention to carry out an order analysis (here in the form of the frequency transformation of a preferably angle-synchronous signal) of the two-mass flywheel vibrations at least on the electric machine control unit. The results of this analysis are slowly changing variables (amplitude and phase of the vibration) and can then be sent via the vehicle bus with slow communication (e.g. 10ms task). Since the internal combustion engine control unit now also receives information about the vibration of the secondary-side two-mass flywheel vibration, the above-mentioned expanded input signal, in particular the signal proportional to the rotary momentum of the electric machine, can be generated for the cylinder equalization controller. A correct input signal can be generated on the one hand by appropriate calculations with the existing phase and amplitudes of all signals and on the other hand by a time signal reconstruction of the signals from the electric machine control unit.

The gas pressures that occur in the combustion engine inevitably lead to an excitation of the entire engine transmission system, which is extremely annoying for the vehicle occupants Vibrations or acoustic hum at low speeds, eg idling, is perceived.

The functional division of tasks between the control units is also relevant, since the combustion engine control unit and the electric machine control unit communicate via a bus network. As a rule, the latency of the bus transmission is too great and varies according to prioritization regulations, so that real-time transmission of a rapidly changing time signal is not possible. For this reason, according to the development of the invention according to the invention, there is a transformation of the angular momentum of the electric machine in the electric machine control device into the frequency range or into the order range. Only vibration-specific values (such as amplitude, phase and frequency or engine order) are generated on the electric machine control unit and transmitted to the combustion engine control unit via the bus. The advantage is that the specific values mentioned only change slowly in many cases (e.g. when idling at a constant low speed) and the bus communication restrictions are therefore sufficient for the implementation of the function. With this procedure, the combustion engine control unit only receives the (almost) constant values and has to transform the frequency signal or order signal from the electric machine control unit back into the time range or angle range.

Assuming at least an elastic coupling of the individual drive train shafts, the absolute angular position of the rotor is identified when the drive train is not rotating or is rotating slowly. The original restriction of the communication speed of the control units involved is irrelevant, since in the case of non-rotating or slowly rotating drive train shafts there is little or no change in the angular positions over time, which means that very slow bus communication is also possible. After the information on the angular position of the electric machine and the angular position of the internal combustion engine has been recorded, the angular positions can be compared and the angular offset can be calculated. The electric machine control unit can deduce the absolute angular position on the basis of the determined angular offset, the internal angle measurement and an incremental pole pair segment count.

The invention can be used in hybrid drives with a petrol or diesel engine as the internal combustion engine.

• 1 schematisch erfindungswesentliche Komponenten und Größen des gesamten Motorgetriebeverbundes,
• 2 schematisch ein erstes Ausführungsbeispiel einer erfindungsgemäßen Vorrichtung gemäß der Grundidee und
• 3 schematisch ein zweites Ausführungsbeispiel einer erfindungsgemäßen Vorrichtung gemäß einer vorteilhaften Weiterbildung der Grundidee.

The invention is described in more detail below using exemplary embodiments. while showing

• 1 schematic of the components and sizes of the entire motor transmission system that are essential to the invention,
• 2 schematically a first embodiment of a device according to the invention according to the basic idea and
• 3 schematically a second embodiment of a device according to the invention according to an advantageous development of the basic idea.

In 1 is a motor-transmission system MGV in a hybrid vehicle with an internal combustion engine VM, with an electric machine EM, with an electric machine control unit EMS, with an internal combustion engine control unit VMS and with a communication bus B between the electric machine control unit EMS and the internal combustion engine control unit VMS . The motor-transmission system MGV is housed in a motor-transmission system housing MGV-G, which can also contain a dual-mass flywheel ZMS, a torque converter clutch WK and a torque converter WD for an automatic transmission (transmission input torque M _GET ). In particular, the internal combustion engine VM and the stator of the electric machine EM are connected to the motor-transmission assembly housing MGV-G in a vibration-relevant manner. In 1 The vibration-relevant forces are shown schematically at the top right: F _L = bearing force, F _SK = lateral piston force, F _EM = force due to the torque of the electric machine EM. According to the invention, it is essentially these forces of the internal combustion engine VM and the electric machine EM that are considered to be relevant to vibrations acting on the rigid motor-transmission composite housing MGV-G.

As a result, spurious vibrations occur in the engine-transmission system MGV, which cause problems with regard to a cylinder equalization function that can usually be implemented using a corresponding cylinder equalization controller or cylinder equalization module ZG in the internal combustion engine control unit VMS. The above problems are to be solved by the invention.

In 2 a drive control unit AS is shown, which has a cylinder equalization controller ZG and is designed in such a way that an input signal ω _corr of the cylinder equalization controller ZG is generated by superimposing the signal ω _KW proportional to the measured crankshaft angular velocity with a signal ω _EM proportional to the angular momentum of the electric machine.

The signal ω _EM , which is proportional to the angular momentum of the electric machine, is generated, for example, in a first evaluation module EWA from a weighted angular velocity signal EWS (Eg from a rotor position sensor) of the electric machine EM and from an integrated torque M_EM of the electric machine EM (integration possibly including zeroing after one or more 2-times EM rotor revolutions to a defined rotor angular position) generated.

In 2 and 3 vibration-relevant variables are shown schematically above. The crankshaft KW (with its moment of inertia J _P ), the electric machine EM (with its moment of inertia Js), the dual mass flywheel ZMS between the crankshaft KW and the electric machine EM and the rest of the drive train (with its moment of inertia Je).

The crankshaft sensor signal KWS is the input signal of the drive control unit AS (in 2 ) or the combustion engine control unit VMS (in 3 ).

3 shows a further development of the 2 . In 3 is (as well as in 1 ) an electronic electric machine control unit EMS, an electronic internal combustion engine control unit VMS and a communication bus B between the electric machine control unit EMS and the internal combustion engine control unit VMS. In 3 is also the first evaluation module EWA accordingly 2 shown.

The electric machine control unit EMS is designed in such a way that in a Fourier transformation module TF, the angle-synchronous signal ω _EM , which is proportional to the angular momentum of the electric machine, is transformed from the time range t to the frequency range ƒ or from the angle range to the order range, and that this is only used for selected engine orders MO _i the amplitudes a _i and phases Φ _i are output via the communication bus B to the internal combustion engine control unit VMS.

The internal combustion engine control unit VMS is designed in such a way that in a Fourier inverse transformation module FT, the amplitudes a _i and phases Φ _i sent via the communication bus B to the internal combustion engine control unit VMS are converted from the frequency range ƒ to the time range t or from the order range to the Angular range to map the angular momentum of the electric machine proportional signal ω _EM 'are transformed back.

Finally, the internal combustion engine control unit VMS includes a cylinder equalization controller ZG and is designed in such a way that an input signal ω _corr of the cylinder equalization controller ZG is generated by superimposing the signal ω _KW , which is proportional to the measured crankshaft angular velocity, with a signal ω _EM ', which is proportional to the angular momentum of the electric machine.

The signal ω _KW proportional to the measured crankshaft angular velocity is formed in a second evaluation module KWA, which first processes the signal from the crankshaft sensor KWS into a discrete crankshaft angle φ _KW and then into a discrete crankshaft angular velocity ω _KW .

In the Fourier transformation module TF, the amplitudes a _i and phases Φ _i are calculated as a function of the electric machine rotor angle for selected orders (see above) with a clear reference to the internal mechanical angle reference point.

In the Fourier inverse transformation module FT, a consistent time signal (eg by means of inverse Fourier transformation) is reconstructed as a function of the discrete crankshaft angle φ _KW and a discrete reference angle φ _ref .

The proposed mathematical arithmetic operations in the illustrated exemplary embodiments can be adapted in accordance with the applicable mathematical arithmetic rules.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102020112471 [0001]

Claims (6)

Device for reducing vibration excitations in a drive train of a hybrid vehicle with an internal combustion engine (VM), with an electric machine (EM) and with at least one electronic drive control unit (AS; EMS, VMS), which has a cylinder equalization controller (ZG) and is configured in this way that an input signal (ω _korr ) of the cylinder equalization controller (ZG) by superimposing a measured crankshaft angular velocity proportional signal (ω _KW ) with an electric machine angular momentum proportional signal (ω _EM; ω _EM ') is generated. device after claim 1 with an electric machine control unit (EMS), with an internal combustion engine control unit (VMS) and with a communication bus (B) between the electric machine control unit (EMS) and the internal combustion engine control unit (VMS), the electric machine control unit (EMS ) is designed in such a way that the signal (ω _EM ), which is proportional to the angular momentum of the electric machine _, is transformed from the time domain (t) to the frequency domain (f) or from the angle domain to the order domain, and that the amplitudes (a _i ) and phases (Φ _i ) are output via the communication bus (B) to the combustion engine control unit (VMS). Device according to one of the preceding claims, characterized in that the internal combustion engine control unit (VMS) is designed in such a way that the amplitudes (a _i ) and phases (Φ _i ) can be transformed back from the frequency domain (f) to the time domain (t) or from the order domain to the angular domain to map the signal (ωEM') proportional to the angular momentum of the electric machine. Hybrid vehicle with a device according to one of the preceding claims. First computer program product for use in the internal combustion engine control unit (VMS) of the device according to one of the preceding claims. Second computer program product for use in the electric machine control unit (EMS) of the device according to one of the preceding claims.

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