DE102020113174A1 - Device for operating a hybrid vehicle with an electronic control unit - Google Patents

Abstract

The invention relates to a device for operating a hybrid vehicle with at least one electrical machine, with an internal combustion engine, with a separating clutch between the internal combustion engine and the electrical machine, with a starting element connected downstream of the electrical machine and with an electronic control unit. The control unit is designed in such a way that it activates a special stationary charging mode when at least one, in particular load-dependent, defined condition is present when the vehicle is stationary. The stationary charging special mode is preferably defined in such a way that the electrical energy storage device is charged by the internal combustion engine before the driver's wish to start off with the disengagement clutch closed and the starting element open, and that afterwards the disconnection clutch is opened when the driver wishes to start and a start-up is controlled exclusively with the electric machine . A defined condition is preferably the detection of a comparatively high load on the vehicle.

Description

The invention relates to a control unit, a device and a method for operating a hybrid drive for a motor vehicle with at least one electric machine for electric motor drive and with an internal combustion engine, each of which can be used individually or together to provide a drive torque requested on a transmission of the vehicle provide.

In the case of hybrid vehicles, various hybrid drive topologies as well as various operating strategies, in particular for reducing emissions and consumption, are known. According to the state of the art, the internal combustion engine should be operated as little as possible. Switching the combustion engine on and off consumes energy and time and (mostly) affects the comfort and dynamics of the vehicle.

A particular load on components, especially when starting off with an already comparatively heavy hybrid vehicle, arises with an additional comparatively high load - for example when the vehicle interior is occupied by a large number of occupants or when the rear area is loaded with a heavy load or when towing a trailer. With a comparatively high load, there is also a loss of range in electrical operation.

For example in the DE 41 21 386 A1 the problem of range is solved by a trailer that supports energy storage. The additional load on a trailer is not taken into account.

The object of the invention is to improve the operation of a hybrid drive while taking into account the range and component protection.

This object is achieved by the features of the independent patent claims. The dependent claims relate to advantageous developments of the invention.

The invention relates to a device for operating a hybrid vehicle with at least one electrical machine and with an internal combustion engine, each of which can be used individually or jointly to drive the vehicle in order to generate a drive torque required on a transmission of the vehicle, with a disconnecting clutch between the internal combustion engine and the electric machine, with a starting element connected downstream of the electric machine (in particular an integrated starting element IAE in the form of a frictional brake) and with an electronic control unit. The control unit is designed in such a way that it activates a special stationary charging mode when at least one (in particular load-dependent) defined condition is present when the vehicle is stationary. An integrated starting element IAE can also be understood as a clutch of a double clutch transmission or as another frictional starting element.

The stationary charging special mode is preferably defined in such a way that the electrical energy storage device is charged by the internal combustion engine to increase the SOC (state-of-charge, common term for the state of charge of a high-voltage battery) at a standstill before the driver wants to start off with the disconnecting clutch closed and the starting element open that afterwards, when the driver wishes to start off (for example recognizable by pressing the accelerator pedal), the separating clutch is opened and starting is controlled exclusively with the electric machine.

The electronic control unit is preferably also designed in such a way that it detects input signals for recognizing a comparatively high load of the vehicle and that a defined condition is the recognition of the comparatively high load.

Furthermore, the electronic control unit is preferably designed in such a way that, when a comparatively high load is detected, it specifies an increased SOC special threshold value compared to a customary minimum permissible SOC and that falling below the increased special threshold value is a defined condition.

All of the aforementioned features in combination result in a particularly advantageous embodiment of the invention.

The invention is based on the following findings:

Future hybrid transmissions use a frictional brake in the transmission ("IAE" = integrated start-up element) as a starting element, especially instead of a torque converter. The integrated starting element IAE cannot be cooled to the same extent as a starting clutch upstream of the gear set, due to the high level of functional and installation space integration in the transmission topology. Therefore, functional approaches are to be implemented with the lowest possible power input. In the so-called PHEV configuration, especially with P2 topology, the e-machine helps with high torque at low speeds, in contrast to the internal combustion engine, which only provides the necessary torque for start-up at high speeds.

Driving off with a heavy load, especially with a trailer, can quickly lead to the IAE overheating without electrical assistance. In the worst case, the electric machine cannot provide any support, particularly in so-called “charge sustaining” (CS) operation with a low battery charge level (SOC).

According to the invention, the information is therefore obtained from the vehicle electrical system on the control device side as to whether there is a comparatively high load (for example, the vehicle interior is occupied by a large number of occupants or a heavy load in the trunk or trailer operation). Depending on this information, an electronic control unit is used to increase a customary minimum permitted SOC threshold value to a minimum permitted SOC special threshold value in the electrical energy store (in particular in CS mode). If the actual SOC value, for example when a trailer is connected, is below this minimum permitted SOC special threshold, the status "Ready", when the vehicle is put into operation or when the drive is started (generally if the combustion engine can be operated at a standstill) Immediately forced charging of the electrical energy storage device by the internal combustion engine in order to maintain the minimum permitted SOC value in the case of a high load in the sense of a stationary charging special operation or a load point increase, for example for a certain number of trailer approaches in the electrical energy storage device.

Use case: If a trailer is attached to a hybrid vehicle with an empty electrical energy storage device (SOC below SOC special threshold value), according to the state of the art, a start-up attempt would only take place with the internal combustion engine. The IAE can overheat because the electrical machine does not provide support. In order to prevent the resulting negative consequences, according to the invention, when the trailer operation is recognized at the next opportunity - that is, when the internal combustion engine can be started at a standstill - a forced charging of the memory is started in order to then ensure the support from the electric machine.

It is pointed out that additional features of a patent claim dependent on an independent patent claim without the features of the independent patent claim or only in combination with a subset of the features of the independent patent claim can form a separate invention independent of the combination of all features of the independent patent claim, which can be made the subject of an independent claim, a divisional application or a subsequent application. This applies equally to the technical teachings described in the description, which can form an invention that is independent of the features of the independent patent claims.

According to a further aspect, a software (SW) program is used in the control unit. The software program can be set up to be executed on a processor of the control unit (e.g. on a control device of a vehicle) and thereby to execute the method described in this document or to thereby enable the device according to the invention.

According to a further aspect, a storage medium is described. The storage medium can contain the SW program for the / a control unit.

It should be noted that the methods, devices and systems described in this document can be used both alone and in combination with other methods, devices and systems described in this document. Furthermore, any aspects of the methods, devices and systems described in this document can be combined with one another in diverse ways. In particular, the features of the claims can be combined with one another in diverse ways.

The invention is described in more detail below on the basis of an exemplary embodiment. The only figure shows ( 1 ) a so-called P2 drive train with idle charging special operation or load point raising operation that can be activated and deactivated according to the invention.

In 1 a P2 powertrain includes an internal combustion engine 3 and an electric machine 5 that can be used individually or together to generate drive torque for a hybrid vehicle 1 to generate. The internal combustion engine 3 and the electric machine 5 are arranged in such a way that the torques generated by the respective drive motor add up to a total drive torque that is generated via a transmission 7th and an output shaft of the transmission 7th on one or more wheels of the vehicle 1 is transmitted. The electrical energy for operating the electrical machine 5 is stored in an electrical energy storage device (high-voltage battery) not shown here.

The vehicle 1 further comprises an electronic control unit 10 (eg a drive control unit) which is set up to determine a requested total drive torque. The requested total drive torque can, for example, via an accelerator pedal and / or via a setting of the transmission 7th specified by a driver of the vehicle will. For example, a driver can operate the accelerator pedal in order to request an increased total drive torque. The control unit 10 can be set up to convert the requested total drive torque into a first torque (for the internal combustion engine 3 ) and in a second moment (for the electric machine 5 ) to split. In other words, the control unit 10 can be set up the internal combustion engine 3 and the electric machine 5 depending on a requested total drive torque and depending on other operating parameters, such as B. to operate depending on the state of charge (SOC) of the electrical energy storage device.

Furthermore shows 1 a disconnect clutch 8th with which the internal combustion engine 3 and the electric machine 5 can be decoupled. Finally, are a start-up element 6th (alternatively, in particular, a gear-integrated start-up element IAE 6 ' in the form of a frictional brake) and optionally a torsional vibration damper 4th that does not necessarily follow the in 1 position shown must be provided. The internal combustion engine 3 can with a variable valve timing device 2 (VVT, VANOS).

The control unit 10 receives input signals via a data bus to other control units or sensors to detect a comparatively high load on the vehicle 1 : For example, a signal AB to identify trailer operation, a signal LL to identify an increased load and / or a signal SB to identify that the vehicle is occupied by a certain number of people. The information AB, LL, SB and / or other signals for recognizing a comparatively high load lead in the control unit to the specification of an increased SOC special threshold value SOC_B. Another signal for recognizing a comparatively high load could also be generated by a corresponding manual input by the driver in a display / operating unit (e.g. BMW iDrive).

• Der SLB wird erstens im Stillstand des Fahrzeugs 1 die Trennkupplung 8 zwischen dem Verbrennungsmotor 3 und der elektrischen Maschine 5 geschlossen (bzw. geschlossen gehalten), das Anfahrelement (6) geöffnet (bzw. offen gehalten) und der elektrische Energiespeicher (Hochvolt-Batterie) durch den Verbrennungsmotor 3 zumindest bis zu einem Anfahrwunsch des Fahrers geladen. Bei Vorliegen eines Anfahrwunsches wird (vorzugsweise bei Bedarf um eine vorgegebene Zeit verzögert) zweitens die Trennkupplung 8 geöffnet und die Anfahrkupplung 6 für einen Anfahrvorgang geschlossen, wobei der Anfahrvorgang ausschließlich mit der elektrischen Maschine 5 gesteuert wird.

If the actual SOC value is below the SOC special threshold value SOC_B when a comparatively high load is detected, the control unit is activated 10 a stationary loading special operation SLB and / or a load point increase mode LPAn_M (when detected during driving or user input during driving), which can preferably be carried out as follows:

• First of all, the SLB is activated when the vehicle is at a standstill 1 the disconnect clutch 8th between the internal combustion engine 3 and the electric machine 5 closed (or kept closed), the starting element ( 6th ) opened (or kept open) and the electrical energy storage (high-voltage battery) by the internal combustion engine 3 charged at least up to a start-up request from the driver. When there is a request to start off (preferably delayed by a specified time if necessary), the second step is to use the separating clutch 8th opened and the starting clutch 6th closed for a start-up process, the start-up process exclusively with the electrical machine 5 is controlled.

The LPAn_M is preferably used to set the SOC special threshold value SOC_B when the control unit 10 in particular, a driver input during a journey is informed of an increased charge level or trailer operation. In this case, the memory is charged by increasing the power on the internal combustion engine beyond what is necessary for the driving task and then by branching off the excess power into the memory.

Furthermore, especially when the SOC special threshold value SOC_B is set, recuperation energy can be used to increase the SOC while driving.

The control unit 10 preferably contains a storage medium 11th in the form of a software program memory for carrying out the special loading mode SLB and / or the load point raising mode LPAn_M. The stand-alone special operation SLB can also be used as an independent invention whenever the SOC threshold values defined for this are not reached.

The present invention is not restricted to the exemplary embodiment shown. In particular, it should be noted that the description and the figure are only intended to illustrate the principle of the proposed methods, devices and systems.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed 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 4121386 A1 [0004]

Claims (7)

Device for operating a hybrid vehicle (1) with at least one electrical machine (5), with an internal combustion engine (3), with a separating clutch (8) between the internal combustion engine (3) and the electrical machine (5), with one of the electrical machines ( 5) downstream start-up element (6) and with an electronic control unit (10) which is designed in such a way that, when the vehicle (1) is at least one defined condition, a stationary charging special operation (SLB) and / or a load point increase when driving Mode (LPAn_M) activated. Device according to Claim 1 , characterized in that the stationary charging special operation is defined in such a way that the electrical energy storage device is charged by the internal combustion engine (3) before the driver's start-up request with the disengaging clutch (8) and the start-up element (6) open, and then the Separating clutch (8) is opened and starting is controlled exclusively with the electric machine (5). Device according to one of the preceding claims, characterized in that the electronic control unit (10) is designed such that it detects input signals (AB, SB, LL) for detecting a comparatively high load of the vehicle (1), and that a defined condition the Detection of the comparatively high load is. Device according to one of the preceding claims, characterized in that the electronic control unit (10) is designed in such a way that it specifies an increased special SOC threshold value (SOC_B) when a comparatively high load is detected and that falling below the increased special threshold value ( SOC_B) is a defined condition. Device according to one of the preceding claims, characterized in that the increased SOC special threshold value (SOC_B) is held for a renewed stopping and restarting as long as the conditions of the increased loading apply. Electronic control unit (10) with a storage medium (11) for a device according to one of the preceding claims. Storage medium (11) for a device according to one of the preceding claims for implementation in the electronic control unit (10).

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