DE102014203668A1 - Control device for operating a road-locked hybrid vehicle - Google Patents

Abstract

The invention relates to a control device for operating a road-coupled hybrid vehicle having a first drive unit associated with a first axis and a second drive unit associated with a second axis, with a selector device that can be operated by the driver for manual change between a purely electrical operating mode and an automatic operating mode and with at least one electronic control unit for controlling the drive units at least partially depending on the operation of the selector, wherein the first drive unit comprises an electric motor and a cooperable with the electric motor automatically switchable two-speed transmission and wherein the second drive unit is an internal combustion engine and cooperating with the internal combustion engine has another transmission.

Description

The invention relates to a control device for operating a road-coupled hybrid vehicle with at least one electronic control unit, with a first drive unit (eg with electric motor as drive motor) assigned to a first axle (eg front axle) and with a second axle ( eg rear axle) associated second drive unit (eg, with internal combustion engine as a drive motor).

The first drive unit and the second drive unit are not coupled via an in-vehicle mechanical clutch or longitudinal lock, but only drive-related via the wheels through the road. Such road-locked hybrid vehicles are also referred to as "axle-split" hybrid vehicles. Preferably, an electric motor is used as a primary engine and an internal combustion engine as a secondary engine.

Various methods for operating a road-locked hybrid vehicle, for example, in German patent applications 10 2012 211 920 . 10 2013 208 965 or 10 2013 219 085 described.

Such hybrid vehicles are in particular in a first operating mode (preferably E-mode for purely electric driving), in which the electric motor is operated as the primary engine alone for drive control, and in a second operating mode (preferably A-mode for automatically controlled electric and / or internal combustion engine driving ), in which the internal combustion engine can be switched on and off automatically as the secondary engine for drive control, can also be operated.

The German patent applications 10 2012 211 920 and 10 2013 208 965 deal with procedures for connecting the secondary motor.

In the German patent application 10 2013 219 085 Drive-oriented driving and consumption-optimizing drive strategies for controlling the primary and secondary motors are emphasized in drive-oriented driving. In contrast, the drive torque distribution is placed on the axes in the foreground in driving dynamics-oriented driving, especially in traction demand.

It is an object of the invention to improve a hybrid vehicle of the type mentioned in terms of an optimal compromise between achieving a high electric starting acceleration with a high driving torque and achieving the highest possible maximum vehicle speed.

This object is achieved by the subject of independent claim 1. Dependent claims are advantageous developments of the invention.

The invention relates to a control device for operating a road-coupled hybrid vehicle having a first drive unit associated with a first axis and a second drive unit associated with a second axis, with a selector device that can be operated by the driver for manual change between a purely electrical operating mode and an automatic operating mode and with at least one electronic control unit for controlling the drive units at least partially also depending on the operation of the selector, wherein the first drive unit comprises an electric motor and cooperating with the electric motor automatically switchable two-speed transmission and wherein the second drive unit is an internal combustion engine and one with the internal combustion engine having cooperating further transmission.

The invention is based on a special electromechanically controllable two-speed transmission with synchronized gear change operations, which is associated with an electric motor as a drive motor. This first (electric) drive unit consisting of an electric motor as the drive motor and the mentioned two-speed transmission acts on a first axis of a hybrid vehicle and is not mechanically connected to a second (internal combustion engine) drive unit on the second axis of the hybrid vehicle.

The control device according to the invention for controlling the gear change in the two-speed transmission takes into account different operating modes in a hybrid vehicle, in particular when changing from an automatic hybrid mode (A mode) to a purely electrical operating mode (E mode) and vice versa.

The invention also relates to a control device for sequencing the gear change in two-speed transmission, which is initiated with a torque reduction of the electric motor, because the device according to the invention provides no coupling between the electric motor and the two-speed transmission.

Preferably, the torque reduction of the electric motor according to the invention is compensated by a gear change on the first axis by the second drive unit on the second axis by road coupling, provided that the second drive unit is not turned off or can not be engaged quickly enough.

The invention is based on the following considerations:

A combination of internal combustion engine and electric motor (= electric motor) enables different operating modes (eg purely electric driving, pure combustion engine driving or combined electric and combustion engine driving). For example, in the A-mode during strong acceleration of the internal combustion engine and the electric motor preferably work together. As a rule, the electric motor serves to accelerate the short-term supply of high torques, since the internal combustion engine has a slower time response.

The invention is explained by way of example with reference to a "split-axle" hybrid vehicle concept in which the electric motor is located as a central drive on the front axle and the internal combustion engine as a central drive on the rear axle. The two drive technologies can be operated independently of one another and can also be coupled to one another functionally with respect to a wheel-torque-related torque structure by means of at least one electronic control unit which is assigned to both drive technologies.

In addition to a technical background, the Applicant's presentation at the 22nd Aachen Colloquium in October 2013 draws attention to some of the concept considerations for the new BMW i8 (planned series use in March 2014) that preceded the invention. Furthermore, the general wheel torque-related torque structure in the context of the coupled drive control by means of an engine control unit (DME) in a road-bound hybrid vehicle to the earlier patent applications DE 10 2011 004 862 and the DE 10 2011 005 962 the applicant pointed out.

Details of the invention are explained in more detail in the following embodiment with reference to the drawing. It shows

1 a schematic representation of a road-coupled hybrid vehicle with the essential components of the invention,

2 a schematic representation of the actuator assembly in the two-speed transmission for adjusting the shift lever positions by means of an electric motor adjustable shift fork and

3 a pictorial representation of the essential processes in an advantageous switching sequence control means of the switching device according to the invention.

In 1 is a so-called road-coupled hybrid vehicle with an electric motor 1 , which acts as the first drive motor, for example, on the front axle VA, and with an internal combustion engine 3 , which acts as a second drive motor on the rear axle HA, shown. A second electric motor 2 can in addition to the internal combustion engine 3 be provided. Furthermore, a second transmission 4 preferably in the form of an electronically controllable automatic transmission (as already known from the prior art of BMW production vehicles) on the input side with the internal combustion engine 3 connected. Analogously, the invention is also for a differently arranged sequence of the components 2 . 3 and 4 applicable.

Also could be the electric motor 1 on the rear axle and the internal combustion engine 3 be arranged on the front axle.

The electric motor 1 works without intermediate clutch with a two-speed gearbox 7 together.

The hybrid vehicle further includes a driver-operable ("Max E-Drive") switch for manually switching between a purely electrical (E-mode) and an automatic (A-mode) operation mode.

Furthermore, in the hybrid vehicle is a per se (for example, BMW production vehicles) known electronic Getriebewähleinrichtung 9 available, about the usual for the driver of the automatic transmission 4 provided driving positions P, R, N and D and a switch position "S" for the selection of a sporty automatic mode are selectable.

Finally, in 1 a well-known kick-down switch KD shown, which is known to be located at the lower end of an accelerator pedal not shown here.

The drive control of the hybrid vehicle is preferably by a first electronic control unit 5 carried out by the principle of a rad torque-related total drive control for all existing drive motors is feasible (known, for example, from the above-mentioned patent applications DE 10 2011 004 862 and the DE 10 2011 005 962 ). Furthermore, for example, also in the control unit 5 or preferably (as shown here) in a mechatronic two-speed transmission 7 locally associated additional control unit 8th According to the invention, a function module GS-E ("transmission control E-drive") included. The function module GS-E is configured, for example, as a software program module. By means of the function module GS-E and the control units 5 and or 8th is the two-speed transmission 7 preferably with the in 3 shown particularly advantageous flow control controlled.

The controllers 5 and 8th are preferably interconnected via a data bus (eg, CAN) and exchange sensor and control signals as needed. For example, the controller 8th from the control unit 5 the vehicle speed v and a signal T0 are obtained as information. The signal T0 is generated when the fuel tank for the internal combustion engine 3 is empty.

With 2 becomes the actuator assembly of the two-speed transmission 7 functionally explained: A shift fork SG is by one of the control unit 8th electrically controllable spindle servo motor SM in a first gear G1 associated first shift lever POS POS, in a neutral position N associated middle shift lever position POS N and in a second gear G2 associated second shift lever position POS G2 translationally displaceable. Via a Hall sensor S, the current actual position of the shift fork SG can be detected. Between the shift lever positions known synchro switching elements SE are provided. The shift lever positions are actually shift lever position ranges given by a necessary play of a slider on the shift fork SG to reduce the frictional loss in the transition to the rotational movement of the collars (known per se).

The control unit 8th has a function module GS-E, which is configured (in particular programmed) that a change between the first gear G1 and the second gear G2 depending on the operation of the selector (Max-E-Drive button) can be introduced.

However, the function module GS-E is also designed (in particular programmed) such that a change between the first gear G1 and the second gear G2 can be initiated as a function of further predetermined conditions.

A gear change is z. B. with a nominal gear jump (eg., In the form of a digital upshift or downshift command within a software program, see also 3 ).

• 1) Wenn während einer Vorwärtsfahrt vom Fahrer die Wähleinrichtung „Max-E-Drive” zum Einschalten des E-Modus bedient wird und die Fahrzeuggeschwindigkeit v in einem definierten unteren Geschwindigkeitsbereich, z. B. 0 < v < 120 km/h, liegt.

A gear change preferably takes place by means of the control device according to the invention-also as an independent idea-as follows: A gear change from the second gear G2 into the first gear G1 is initiated when at least one of the given conditions is present:

• 1) If, during a forward drive, the driver operates the Max-E-Drive selector to turn on the E-mode and the vehicle speed v is within a defined lower speed range, e.g. B. 0 <v <120 km / h, is located.

Note: The lower speed range is generally determined upward by the maximum possible vehicle speed v in first gear G1 in E mode. Switching on the E-mode at higher vehicle speed v causes a delay in the gear change until reaching the lower speed range.

• 2) Wenn nach einer Rückwärtsfahrt, während der vom Fahrer die Wähleinrichtung (Max-E-Drive-Taster) zum Einschalten des E-Modus bedient wurde, wieder eine Vorwärtsfahrt erfolgt.

OR

• 2) If, after a reverse drive while the driver has operated the selector (Max E-Drive button) to switch on the E-mode, the vehicle will move forward again.

Note: During reverse, 2nd gear is maintained.

• 3) Wenn ein Signal (T0) vorliegt, das bei Vorliegen eines leeren Kraftstofftanks erzeugbar ist.

OR

• 3) If there is a signal (T0) that can be generated in the presence of an empty fuel tank.

Note: This gear change is associated with an automatic switch-on of the E-mode connected exceptionally without using the selector (Max-E-Drive button), as otherwise the vehicle could not continue (availability aspect, emergency operation).

• – wenn ausgehend vom eingeschalteten E-Modus vom Fahrer ein Kick-Down-Schalter KD betätigt wird ODER
• – wenn ausgehend vom eingeschalteten E-Modus vom Fahrer ein sportlicher Modus S angewählt wird ODER
• – wenn das Hybridfahrzeug abgestellt oder neu gestartet wird ODER
• – wenn der elektrische Energiespeichers für den Betrieb des Elektromotors 1 eine definierte maximal zulässige Entladung erreicht hat.

A gear change from the first gear G1 to the second gear G2 is initiated when at least one of the predetermined conditions is present:

• If a kickdown switch KD is actuated by the driver on the basis of the switched on E-mode OR
• If, starting from the switched on E-mode by the driver, a sporty mode S is selected OR
• - when the hybrid vehicle is parked or restarted OR
• - If the electrical energy storage for the operation of the electric motor 1 has reached a defined maximum allowable discharge.

• – in einer ersten Stufe I wird das Drehmoment M_E des Elektromotors 1 auf zumindest nahezu null reduziert (da das Zwei-Gang-Getriebe keine Kupplung aufweist, die zur Kraftschlussunterbrechung geöffnet werden kann),
• – in einer zweiten Stufe II wird der Kraftschluss zwischen dem Elektromotor 1 und dem Getriebe 7 durch Einstellen der Schaltgabel SG in die der Neutralstellung N zugeordnete mittlere Schalthebelposition POS N aufgehoben,
• – in einer dritten Stufe III wird bei Beibehaltung der Neutralstellung N mittels entsprechender Regelung oder Steuerung des Drehmoments M_E des Elektromotors 1 eine Haupt-Synchronisation der Drehzahl n des Elektromotors 1 an den neuen Gang (hier G2) bei gegebener Fahrzeuggeschwindigkeit v bis zum Erreichen einer vorgegebenen vergleichsweise geringen Drehzahlabweichung dn vorgenommen und
• – in einer vierten Stufe IV wird zum Einlegen des neuen Ganges (hier G2) eine Rest-Synchronisation – siehe Bereich i – durch Überwindung der verbleibenden Drehzahlabweichung dn mittels des mechanisch wirkenden Synchroschaltelements SE vorgenommen.

A self-inventive idea is the sequence control of a gear change according to 3 , which is carried out in the following stages:

• - In a first stage I, the torque M _{E of} the electric motor 1 reduced to at least nearly zero (since the two-speed transmission does not have a clutch that can be opened for traction interruption),
• - In a second stage II, the adhesion between the electric motor 1 and the transmission 7 canceled by setting the shift fork SG in the middle shift lever position POS N assigned to the neutral position N,
• - In a third stage III is maintained while maintaining the neutral position N by means of appropriate control or regulation of the torque M _{E of} the electric motor 1 a main synchronization of the speed n of the electric motor 1 to the new gear (here G2) at a given vehicle speed v until a predetermined comparatively low speed deviation dn is reached and
• - In a fourth stage IV to insert the new gear (here G2) a residual synchronization - see area i - made by overcoming the remaining speed deviation dn by means of the mechanically acting synchro switching element SE.

Preferably, in the fourth stage IV, after the region i in which the synchronization takes place, the free flight takes place in the region ii. In the area iii, the shift fork SG is set to the mechanical stop of the shift lever position POS G2. Finally, in area iv, a friction-reducing release of the sliding block described above takes place. In the area V can for further acceleration of the vehicle, the torque M _{E of} the electric motor 1 , optionally together with the internal combustion engine 3 to be raised again.

In this embodiment, from a desired gear jump from the first gear G1 in the second G2, z. B. at a high train at 120 km / h, ie at the upper limit of the defined lower speed range, assumed. In this case, therefore, the M-mode is left to achieve a higher vehicle speed with the cooperation of the second drive unit.

• – lang-gestrichelter Verlauf = Sollgang-Sprung als Einleitungs-Befehl für eine Hochschaltung vom ersten Gang G1 in den zweiten Gang G2 zum Zeitpunkt A;
• – dünner durchgezogener Verlauf = Fahrzeuggeschwindigkeit v mit leichtem Anstieg;
• – kurz-gestrichelter Verlauf = Drehmoment M_E des Elektromotors 1, der zum Zeitpunkt B nahezu null ist und zum Zeitpunkt C null ist
• – fetter durchgezogener Verlauf = Stellung der Schaltgabel SG bzw. Verstellweg in %, wobei vom Zeitpunkt B, wenn das Drehmoment M_E nahezu null ist, die Schalthebelposition POS G1 vom ersten Gang G1 bis zum Zeitpunkt C in die Schalthebelposition N verstellt wird;
• – strichpunktierter Verlauf = Drehzahl n des Elektromotors 1, die hier vor dem Gangwechsel etwa 9200 U/min aufbringt und nach dem Gangwechsel eine Synchrondrehzahl von etwa 5800 U/min aufbringen soll; zum Zeitpunkt D ist die Synchrondrehzahl plus einer vorgegebenen Drehzahlabweichung dn erreicht; bis zum Zeitpunkt D bleibt das Zwei-Gang-Getriebe in der Neutralstellung N, damit das Drehmoment M_E rucklos zur Drehzahlregelung verstellbar ist.

In 3 the following courses are shown:

• Long-dashed curve = target gear jump as an initiation command for an upshift from first gear G1 to second gear G2 at time A;
• - thin solid line = vehicle speed v with a slight increase;
• - short-dashed curve = torque M _{E of} the electric motor 1 which is nearly zero at time B and zero at time C
• Solid solid curve = position of the shift fork SG or displacement in%, wherein from time B, when the torque M _{E is} almost zero, the shift lever position POS G1 is shifted from the first gear G1 to the time C in the shift lever position N;
• - dot-dash line = speed n of the electric motor 1 , which applies here before the gear change about 9200 U / min and after the gear change to apply a synchronous speed of about 5800 U / min; at time D, the synchronous speed plus a predetermined speed deviation dn is reached; until time D, the two-speed transmission remains in the neutral position N, so that the torque M _{E is} steplessly adjustable for speed control.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 102012211920 [0003, 0005]
• DE 102013208965 [0003, 0005]
• DE 102013219085 [0003, 0006]
• DE 102011004862 [0016, 0027]
• DE 102011005962 [0016, 0027]

Claims (8)

Control device for operating a road-coupled hybrid vehicle with a first drive unit associated with a first axis (VA) and with a second drive unit assigned to a second axle (HA), with a selector device (Max E-Drive pushbutton) that can be operated by the driver for manual change between one electrical operating mode (E-mode) and an automatic operating mode (A-mode) and with at least one electronic control unit ( 5 . 8th ) for controlling the drive units at least partially depending on the operation of the selector (Max-E-Drive button), wherein the first drive unit is an electric motor ( 1 ) and one with the electric motor ( 1 ) cooperating automatically switchable two-speed transmission ( 7 ) and wherein the second drive unit is an internal combustion engine ( 3 ) and one with the internal combustion engine ( 3 ) cooperating further transmission ( 4 ) having. Control device according to claim 1, characterized in that the two-speed transmission ( 7 ) has a shift fork (SG), which by one of the at least one control unit (SG) 5 ; 8th ) electrically controllable servo motor (SM) in a first gear (G1) associated first shift lever position (POS G1), in a neutral position (N) associated with middle shift lever position (POS N) and in a second gear (G2) associated second shift lever position ( POS G2) is translationally displaceable. Control device according to one of the preceding claims, characterized in that the at least one control unit ( 5 ; 8th ) has a function module (GS-E) and is thus configured such that a change between the first gear (G1) and the second gear (G2) can be initiated depending on predetermined conditions. Control device according to one of the preceding claims, characterized in that the at least one control unit ( 5 ; 8th ) has a function module (GS-E) and is thus configured such that a change between the first gear (G1) and the second gear (G2) at least depending on the operation of the selector (Max-E-Drive button) can be introduced , Control device according to one of the preceding claims, characterized in that the at least one control unit ( 5 ; 8th ) has a function module (GS-E) and is thus configured such that a gear change from the second gear (G2) in the first gear (G1) can be introduced if at least one of the predetermined conditions is present: - if during a forward drive from the driver the selector (Max-E-Drive button) has been operated to switch on the E-mode and the vehicle speed (v) is within a defined lower speed range (0 <v <120 km / h) or - if after a reverse drive, in the the driver has operated the selector device (Max-E-Drive) to switch on the E-mode, a forward drive is made again or - if there is a "fuel tank emptied" signal (T0). Control device according to one of the preceding claims, characterized in that the at least one control unit ( 5 ; 8th ) has a function module (GS-E) and is thus designed such that a gear change from the first gear (G1) in the second gear (G2) is then introduced if at least one of the predetermined conditions is present: - if starting from the switched-E Mode by the driver a kick-down switch (KD) is operated or - when starting from the switched on E-mode by the driver a sporty mode (S) is selected or - when the hybrid vehicle is turned off or restarted or - if the electric energy storage for the operation of the electric motor ( 1 ) has reached a defined maximum allowable discharge. Control device according to one of the preceding claims, characterized in that the at least one control unit ( 5 ; 8th ) has a function module (GS-E) and is thus designed such that a gear change sequence control in the following stages is feasible: - in a first stage (I), the torque (M _E ) of the electric motor ( 1 ) can be reduced to at least almost zero, - in a second stage (II) the adhesion between the electric motor ( 1 ) and the transmission ( 7 ) can be canceled by setting the shift fork (SG) in the middle shift lever position (POS N) assigned to the neutral position (N), - in a third stage (III) while maintaining the neutral position (N) by means of appropriate regulation or control of the torque (M _E ) of the electric motor ( 1 ) a main synchronization of the speed (n) of the electric motor ( 1 ) with the new gear (G1, G2) at a given vehicle speed (v) until reaching a predetermined speed deviation (dn) vornehmbar and - in a fourth stage (IV) is to engage the new gear (G1, G2) a residual synchronization (i) vorzugbar by overcoming the remaining speed deviation (dn) by means of a mechanically acting synchro switching element (SE). Control unit ( 8th ) with a function module (GS-E) for controlling the two-speed transmission ( 7 ) for use in a control device according to any one of the preceding claims.

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