Method for operating a motor vehicle and motor vehicle

Abstract

The method involves checking a start-stop-controlling device (30) of a motor vehicle (10) before initiating a stopping operation and / or before initiating a starting operation for an internal combustion engine (12) in a predetermined time internal for determining whether a start authorization is provided for new starting of the engine. The stopping operation and / or starting operation is initiated by the controlling device only when the start authorization is present, and a warning signal is provided by the controlling device during the absence of the start authorization. An independent claim is also included for a motor vehicle comprising an internal combustion engine and a starting device.

Description

[0001] The invention relates to a method for operating a motor vehicle equipped with an internal combustion engine, a starting device for starting the internal combustion engine and a start-stop control device for controlling the internal combustion engine and the starting device, as well as a motor vehicle.

[0002] The use of start-stop control devices in motor vehicles equipped with internal combustion engines is known. A start-stop control device enables the automatic shutdown and automatic restart of the internal combustion engine, depending on the driving condition of the motor vehicle, in order to ensure economical operation of the motor vehicle. The driver of the motor vehicle does not need to take any action beyond operating the basic functions (accelerator, brake, clutch, gearshift) of the motor vehicle. Automatic shutdown of the internal combustion engine is carried out in particular when no drive power needs to be supplied by the internal combustion engine.In a motor vehicle equipped with a manual transmission, such a driving condition occurs when the vehicle, with the clutch engaged (i.e., with power transmission disengaged between the internal combustion engine and the drive wheels), falls below a predetermined minimum speed for a specified period. This driving condition can occur, for example, when waiting at a traffic light. Automatic engine restart is triggered, in particular, by releasing the service brake or parking brake, or by pressing the accelerator pedal, without the driver having to take any additional actions.The start-stop control device influences the energy and / or fuel supply to the internal combustion engine as well as a starting device that provides the necessary kinetic energy to bring the internal combustion engine from a standstill to a minimum speed from which autonomous operation and power output of the internal combustion engine are possible.

[0003] From EP 1 612 408 A1, a method for automatically stopping and starting an internal combustion engine in a motor vehicle is known, in which the internal combustion engine is temporarily switched off in certain driving conditions to save fuel and is restarted by actuating the brake pedal. Particular emphasis is placed on driving conditions such as those encountered by delivery vans used for delivering packages. In these situations, the driver often leaves the vehicle, and it is assumed here that the internal combustion engine is switched off when the driver leaves the vehicle in order to save fuel and protect the environment.The vehicle is parked using a remote key. Its presence within a predefined radius of the vehicle unlocks the doors and prepares the vehicle for starting, while its absence locks the doors and deactivates the vehicle's start readiness. The combustion engine is automatically started when the driver explicitly requests to start the engine, for example, by pressing the clutch pedal. This prevents unnecessary starting attempts.

[0004] The object of the invention is to provide a method for operating a motor vehicle and a motor vehicle that enable safe use of the start-stop functions.

[0005] This problem is solved by a method having the features of claim 1 and by a motor vehicle having the features of claim 5. Advantageous embodiments of the invention are the subject of dependent claims.

[0006] According to the invention, the start-stop control unit checks, before initiating a stop process and / or before initiating a start process for the internal combustion engine, particularly at predetermined intervals, whether authorization to restart the internal combustion engine exists, and that the start-stop control unit initiates the stop process or the start process only if authorization to restart exists. The authorization to restart is preferably linked to an object. For example, the object can be designed as a key for insertion into an ignition lock, which may optionally contain additional start authorization information to be transmitted via wired or wireless means, or the object can be designed as a chip card for the wired and / or wireless transmission of start authorization information.The decisive factor is that the starting authorization exists if the object intended to prove the starting authorization is located in a designated place (in particular the ignition lock) or is at least within a predefinable transmit-receive range of a starting authorization query device.

[0007] If the starting authorization is granted, the driver can start the motor vehicle. The starting process is initiated as soon as the driver gives a corresponding command. Such a command can be given, in particular, by turning a key in an ignition lock, by pressing a start button, by pressing the accelerator pedal, by releasing the brake pedal, or by operating a selector lever. The start command can be given for an automatic transmission, or by depressing the clutch pedal to engage a gear in a manual transmission, or by a combination of these actions. Before executing the start command, the start-stop control unit may check further boundary conditions to ensure safe vehicle start-up, such as the depressurization of the brake pedal in a vehicle with an automatic transmission.

[0008] Once the motor vehicle has been started, the start-stop control unit can generate a stop request for the internal combustion engine for predefined situations, which brings the internal combustion engine to a standstill. The stop request can be triggered in particular by a change in the driving state, especially by falling below a predefinable minimum speed and depressing the clutch pedal to interrupt the power flow while a gear is engaged, or by a prolonged standstill of a motor vehicle equipped with an automatic transmission. When a stop request is received, the start-stop control unit initiates the stopping process for the internal combustion engine. The internal combustion engine can be brought to a standstill, for example, by shutting off the fuel supply and / or by switching off the ignition energy.

[0009] According to the invention, it is provided that before initiating the stopping process, it is checked whether the starting authorization is still valid. The stopping process should only be initiated if the starting authorization is still valid. However, the starting authorization may have expired since the last starting process if, for example, the item authorizing the start has been lost in the meantime. If the driver had placed the chip card authorizing the start in the vehicle and it was, for example, blown out of the vehicle by the wind, the situation arises that a restart would no longer be possible if the internal combustion engine were to shut down automatically, since the driver's starting authorization is checked before the starting process is carried out. In the above case, the starting authorization is no longer valid at this point because the corresponding chip card has been lost.The driver would thus be unable to start the vehicle, leading to significant disruptions. In contrast, the inventive method checks whether the start authorization still exists before the internal combustion engine is switched off. Even if start authorization is lacking, it is assumed that the authorized driver is still operating the vehicle, so that switching off the internal combustion engine, coupled with the impossibility of restarting, would be unjustified. In such a situation, the invention prevents the automatic switching off of the internal combustion engine by the start-stop control unit, thus overriding the start-stop strategy pursued by the start-stop control unit.

[0010] Furthermore, it can be additionally or alternatively provided that, before an automatic start process for the internal combustion engine, i.e., one initiated by the start-stop control unit and which usually follows a stop process initiated by the start-stop control unit, the start authorization is checked. A start process only takes place if start authorization is present, which is triggered, for example, by engaging a gear or by depressing the clutch pedal as part of the start-stop strategy. This prevents the vehicle from being started by an unauthorized person or mistakenly by the authorized person after an automatic shutdown. If the authorized driver leaves the vehicle after an automatic shutdown of the internal combustion engine, they usually also take with them the item(s) authorizing the start.If the driver later returns to the vehicle without the item authorizing the start, the method according to the invention prevents the driver from starting the internal combustion engine solely by operating the motor vehicle in accordance with the predetermined start-stop strategy.

[0011] Otherwise, the situation could arise that, after losing the object authorizing the start and after completely switching off the internal combustion engine, for example by pressing a switch-off button, the driver discovers at another location and upon wanting to restart the engine that he no longer has the object authorizing the start with him and then possibly gets stranded in a place that is far away from where the object authorizing the start is located.

[0012] In an embodiment of the invention, the start-stop control unit deactivates a start-stop strategy until the start authorization is received again. This allows the motor vehicle to continue driving as soon as the object authorizing the start is back within the reception range of the start-stop control unit.

[0013] In a further embodiment of the invention, it is provided that the start-stop control unit deactivates a start-stop strategy until the start authorization is available again and, in addition, a start request from the driver that is independent of the start-stop strategy is present. This ensures that the driver, after leaving the vehicle, in which the starting authorization is not available, The system ensures that the driver, having been removed from the vehicle's reception range, is not surprised by an automated start-up process upon re-entering the vehicle, such as when a gear is engaged or the clutch pedal is depressed. Instead, the system requires the driver to perform an action beyond simply operating the vehicle, such as pressing a start button, before the engine starts.

[0014] In a further embodiment of the invention, the start-stop control unit is provided that it issues a warning signal if the start authorization is missing. This ensures that the driver is immediately informed of the reason why the vehicle cannot be started if the start authorization is missing. The warning signal can be issued visually and / or audibly, for example by an indicator light and / or a warning tone. The warning signal can also be issued if the object authorizing the start is lost while the internal combustion engine is running.

[0015] According to a further aspect of the invention, a motor vehicle is provided with an internal combustion engine and a starting device for starting the internal combustion engine, which has a start-stop control device for controlling the internal combustion engine and the starting device, which is configured to carry out the method according to one of claims 1 to 4.

[0016] In a further embodiment of the invention, the starting device is designed as an integrated starter generator (ISG), in particular as a belt-driven integrated starter generator (B-ISG). An integrated starter generator performs both the function of a generator for producing electrical energy and of a starter for providing kinetic energy for the starting process of the internal combustion engine. The integrated starter generator is preferably coupled to the crankshaft of the internal combustion engine via a drive belt, e.g., a toothed belt, or is directly flanged to the crankshaft.The integrated starter generator is preferably in constant power transmission connection with the internal combustion engine and can therefore (especially in contrast to a standard starter motor with pinion engagement in a flywheel) provide kinetic energy to the internal combustion engine at any given time. It is also conceivable to make the power transmission connection between the integrated starter generator and the internal combustion engine separable by means of a switchable or speed-dependent clutch device, whereby an immediate supply of kinetic energy can also be ensured in this case.

[0017] Further advantages and features of the invention will become apparent from the claims and from the following description of advantageous embodiments, which are illustrated with reference to the drawings. These show:

[0018] Fig. 1 shows a schematic representation of a motor vehicle with an internal combustion engine, an integrated belt-driven starter generator and a start-stop control device,

[0019] Fig. 2 is a flowchart illustrating the start-stop procedure.

[0020] Figure 1 schematically depicts a motor vehicle 10 with the essential components that play a role in carrying out a start-stop procedure with the possibility of aborting the stopping process. For the sake of clarity, other components necessary for the operation of the motor vehicle 10 are not shown.

[0021] The motor vehicle 10 has an internal combustion engine 12, which is connected via a clutch assembly 14 to a manual transmission 16, to which drive wheels 18 are flanged. When the clutch 14 is engaged, the torque delivered by the internal combustion engine 12 is converted by the transmission 16 into an output torque for the drive wheels 18, thus enabling the motor vehicle 10 to move.

[0022] The vehicle speed 10 is controlled by adjusting the power supplied by the internal combustion engine 12 and by selecting the appropriate transmission setting or gear (forward gears, reverse gear). These adjustments are made via familiar controls such as the accelerator pedal 20 and the gear selector lever 22, which are operated by the driver. A clutch pedal 24 is used to actuate the clutch 14 via an actuator (not shown) and thus to disconnect and reconnect the power flow between the internal combustion engine 12 and the transmission 16. Actuating the clutch pedal 24 disengages the clutch 14 and thus enables the engagement of the various gears. The vehicle speed 10 can also be controlled by means of a brake pedal 26, which acts via brake lines on a brake system (not shown) assigned to the drive wheels 18.

[0023] The operating positions of the control elements 20, 22, 24, 26 are detected by means of sensors not shown in detail, the signals of which are transmitted via signal lines 28 to a start-stop control unit The direction 30 is transmitted. By deriving the actuation positions over time, the actuation speeds for the control elements 20, 22, 24, and 26 can also be determined. The start-stop control unit 30 is connected via additional control lines 28 to components such as a battery monitoring system 32, an ignition control unit 34, a fuel injection unit 36, and a sensor arrangement 38 associated with the internal combustion engine 12. The control unit 30 can also process values ​​determined by these components and issue control commands to them.

[0024] The schematically illustrated sensor arrangement 38 on the internal combustion engine comprises sensors such as a speed sensor, an air mass meter, a coolant temperature sensor, an oil temperature sensor and / or other sensors for determining operating characteristics of the internal combustion engine 12.

[0025] The internal combustion engine 12 is associated with an integrated starter generator 40, which is permanently coupled to the crankshaft of the internal combustion engine 12 (not shown) via a belt 42 (belt-driven integrated starter generator – B-ISG). The starter generator 40 is electrically connected to the start-stop control unit and to a battery 44, which is used as an energy storage device for electrical energy. In its function as a starter, the starter generator 40 provides kinetic energy to accelerate the internal combustion engine 12 from standstill to a minimum speed at which independent operation of the internal combustion engine 12 is possible. In its function as a generator, the starter generator 40 converts kinetic energy of the internal combustion engine 12 into electrical energy, which is stored in the battery 44. The control or regulation of the kinetic energy to be provided by the starter generator 40 is carried out by the start-stop control unit and the start-stop control unit.The conversion of electrical energy is carried out by the start-stop control unit 30. The starter generator 40 is dimensioned so that it can provide an auxiliary torque even when the internal combustion engine 12 is running, in order to improve the acceleration of the vehicle or even to enable purely electric propulsion of the vehicle 10, especially at low speeds.

[0026] The start-stop control device 30 is configured such that the internal combustion engine 12 can be automatically switched off and started. The internal combustion engine 12 is switched off when it does not need to supply power to the drive wheels or to consumers such as a belt-driven air conditioning compressor 46 for a predefinable period of time.

[0027] In order to ensure economical and environmentally friendly operation of the motor vehicle 10, a stop request is generated in the start-stop control unit when one or more of the following conditions are present and is used to control the internal combustion engine 12, the ignition control unit 34, the fuel injection unit 36 ​​and the starter generator 40, in particular to interrupt the fuel supply and / or the ignition energy supply to the internal combustion engine 12.

[0028] The start-stop control device 30 checks in particular whether, after the vehicle 10 has fallen below a minimum speed, the actuation position and / or actuation speed of the accelerator pedal 20 and / or the clutch pedal 24 and / or the brake pedal 26 and / or the gear selector lever 22 is within a predefinable range of values ​​such that a stop request is meaningful.

[0029] The method illustrated in Fig. 2 with reference to the flowchart is initiated by a start command triggered by the driver. This start command can be given, for example, by pressing a start button (not shown). After the start-stop control unit 30 has detected the activation of the start button, it checks whether authorization to start the motor vehicle 10 exists. This authorization can, in particular, be linked to the presence of a wirelessly readable chip card within the transmit-receive range of a driving authorization system (not shown) associated with the start-stop control unit 30. If the correct chip card is within the transmit-receive range of the driving authorization system, the system issues an authorization signal to the start-stop control unit 30, which then initiates the starting process for the internal combustion engine 12.If there is no authorization to start the internal combustion engine 12, the internal combustion engine 12 will not be started and a warning signal may be issued.

[0030] If authorization to start the process is granted, the internal combustion engine 12 is started and the motor vehicle 10 can be driven. During driving, the start-stop control unit 30 can automatically shut down the internal combustion engine 12 without requiring any action from the driver. For example, the automated shutdown can occur if the brake pedal 26 and the clutch pedal 24 are pressed for an extended period. For this purpose, the start-stop control unit 30 generates a stop request for the internal combustion engine 12. Before executing the stop request, the start-stop control unit 30 checks whether the conditions at the beginning of the start-up process are met. The presence of the chip card within the reception range of the driving authorization system is still detected by the vehicle 10. If this is the case, the internal combustion engine 12 is automatically stopped, in particular by switching off the ignition control unit 34 and / or the fuel injection unit 36. If, at this time, there is no longer any authorization to start the internal combustion engine 12, for example because the chip card has blown out of the vehicle 10 or has been lost in some other way, the internal combustion engine 12 is not automatically switched off and a warning message is issued to the driver.

[0031] If, however, the internal combustion engine 12 could be stopped automatically, the driver can now leave the vehicle 10 without permanently switching off the start-stop control unit 30, for example, to run a short errand. If the driver then returns and operates one or more controls of the vehicle 10, such as the accelerator pedal 20 or the clutch 24, the start-stop control unit 30 generates a start request. If a start request exists and the driver still carries the chip card as proof of authorization to start the internal combustion engine 12, the internal combustion engine 12 can be started. If, however, the driver no longer carries the chip card, the intended check of start authorization fails, and the internal combustion engine 12 cannot be started.Instead, a corresponding warning message is issued, informing the driver that he is not authorized to start.

[0032] In another embodiment, it may be provided that, in addition, a query of a starter button is provided to check the existence of the driving authorization after the automated execution of a stop process. Thus, even if the start authorization is successfully checked after the start request has been determined, an action by the driver aimed at starting the internal combustion engine 12 is required. This prevents the internal combustion engine from starting unexpectedly.

[0033] In another embodiment of the invention, the existence of the start authorization is checked in regular or irregular cycles and, in the event of loss of the start authorization, a warning message is issued regardless of an impending automated stop or start process. QUOTES INCLUDED IN THE DESCRIPTION

[0034] This list of documents cited by the applicant was generated automatically and is included solely for the convenience of the reader. The list does not form part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0035] - EP 1612408 A1

[0003]

Claims

[1] Method for operating a motor vehicle (10) which is equipped with an internal combustion engine (12), a starting device (40) for starting the internal combustion engine (12) and a start-stop control device (30) for controlling the internal combustion engine (12) and the starting device (40), characterized in that the start-stop control device (30) checks, before initiating a stop process and / or before initiating a start process for the internal combustion engine (12), in particular repeatedly at a predefinable time interval, whether there is authorization to restart the internal combustion engine (12), and that the start-stop control device (30) initiates the stop process or the start process only if authorization to start is present. [2] Method according to claim 1, characterized in that the start-stop control device (30 ) deactivates a start-stop strategy until the start correction is available again. [3] Method according to claim 1, characterized in that the start-stop control device (30 ) deactivates a start-stop strategy until the start authorization is available again and an additional start request from the driver is available that is independent of the start-stop strategy. [4] Method according to one of the preceding claims, characterized in that the start-stop control device (30 ) issues a warning signal when there is no start authorization. [5] Motor vehicle (10 ) with an internal combustion engine (12 ) and a starting device (40 ) for starting the internal combustion engine (12 ), characterized by a start-stop control device (30 ) for controlling the internal combustion engine (12 ) and the starting device (40 ), which is configured to carry out the method according to one of claims 1 to 4. [6] Motor vehicle according to claim 5, characterized in that the starting device (40 ) is designed as an integrated starter generator, in particular as a belt-coupled integrated starter generator.