Start-stop device for initiating an automatic shutdown process of a drive motor

Abstract

A start-stop device for initiating an automatic shutdown process of a drive motor in a motor vehicle, which is configured to automatically shut off the drive motor when predetermined shutdown conditions are met, wherein the start-stop device (SSE) comprises a stop coordinator (SK) which, based on available information (v, gs), identifies a suitable shutdown behavior for the shutdown process and, when initiating an automatic shutdown process, ensures that the identified shutdown behavior is achieved, characterized in that the stop coordinator (SK) is configured depending on available operating parameters of the motor vehicle (v,gs) to select a stop operating mode to be initiated from at least two stop operating modes, each with a defined shutdown behavior, and to initiate an automatic shutdown of the drive machine in accordance with the selected stop operating mode in order to achieve the corresponding shutdown behavior.

Description

[0001] The invention relates to a start-stop device for initiating an automatic shutdown process of a drive motor in a motor vehicle.

[0002] Currently, internal combustion engines are usually switched off manually by the driver using an ignition key or by operating a control. An exception is a method presented in DE 100 23 331 A1. In this method, the brake pedal position or pressure is evaluated instead of the ignition key. The engine shutdown process is initiated when, after the vehicle has come to a standstill, the brake pedal is pressed further while already in its depressed position. To continue driving, the brake pedal is released and the accelerator pedal is pressed, whereupon the engine restarts. A disadvantage of such methods is that the driver alone is responsible for switching off the engine. Analyses of current driving behavior show that, despite increased environmental awareness and rising fuel prices, manually switching off the internal combustion engine, e.g.,at traffic lights, rarely done independently.

[0003] To reduce fuel consumption and pollutant emissions, systems are already being used in vehicles that automatically switch off the internal combustion engine under certain conditions or when predefined shutdown conditions are met, and automatically switch it back on when predefined startup conditions are met. Such methods and systems, or start-stop devices, are particularly suitable for reducing fuel consumption in urban traffic, since in city traffic the vehicle often comes to a stop at traffic lights or due to traffic conditions, and the operation of the internal combustion engine is not necessary.

[0004] Currently, various engine shutdown and start logics, each with its own advantages, are used by different vehicle manufacturers. For example, some vehicles with automatic transmissions automatically shut off the engine when the driver brings the vehicle to a complete stop. The engine restarts as soon as the brake pedal is released. Another shutdown logic for automatic vehicles stipulates that the engine shuts off only after approximately one second has passed since the vehicle has come to a complete stop.

[0005] Furthermore, DE 10 2010 000 615 A1 discloses an automatic shutdown logic for automatic vehicles, whereby the engine is switched off when a predetermined speed (e.g., 20 km / h) is undershot. If, subsequently, a zero speed is measured while the engine is off (the actual speed may not be zero due to sensor inaccuracies), a brake control system is activated with a successive increase in braking force to maintain a standstill.

[0006] Finally, DE 10 2014 206 509 A1 discloses a start-stop system for a motor vehicle, wherein the engine can be operated in two different stop-start operating modes with different shutdown conditions, in which the engine is stopped when the respective stop conditions are met. The selection of the stop-start operating mode to be used is made by means of a user input device operated by the driver, i.e., the driver selects which start-stop operating mode is valid and should be executed.

[0007] For further information on the state of the art, reference is made to DE 10 2007 009 833 A1, DE 10 2009 045 686 A1 and DE 10 2014 226 004 A1.

[0008] The object of the invention is now to provide a start-stop device which enables improved adaptation of the shutdown process to the current situation.

[0009] This problem is solved according to the invention by a start-stop device according to claim 1. Advantageous embodiments are the subject matter of the dependent claims.

[0010] The invention relates to a start-stop device, known in principle, for initiating an automatic shutdown process of a drive motor in a motor vehicle, which is configured to automatically shut off the drive motor when predetermined shutdown conditions are met. In particular, the automatic shutdown of the drive motor can be initiated under the given shutdown conditions either while the vehicle is (still) in motion (e.g., at low speeds) or while the vehicle has already come to a standstill or is near standstill.

[0011] The invention is further based on the understanding that, with known shutdown procedures, a conflict of objectives can arise regarding the shutdown behavior between shutdown convenience (including shutdown timing), restart capability, and engine shutdown position, since different shutdown behaviors are advantageous depending on various boundary conditions. The invention is therefore based on the idea of ​​providing a system that independently resolves this conflict of objectives.

[0012] Taking into account the above considerations, the invention relates to a start-stop device for initiating an automatic shutdown process of a drive motor in a motor vehicle with an automatic transmission, automated transmission or manual transmission, wherein the start-stop device comprises a stop coordinator which, based on available information, identifies a shutdown behavior suitable for the shutdown process and, when initiating an automatic shutdown process, causes the identified shutdown behavior to be achieved.

[0013] According to the invention, the stop coordinator is configured to select a suitable stop operating mode from at least two stop operating modes, each with a defined, different shutdown behavior, based on available information or operating parameters of the motor vehicle. The coordinator then initiates an automatic shutdown of the drive motor to achieve the corresponding shutdown behavior in accordance with the selected stop operating mode. The different stop operating modes can be designed such that they are fundamentally based on the same shutdown requirements but differ in their shutdown behavior, or that they differ both in the necessary shutdown requirements and in their shutdown behavior.

[0014] In a further advantageous embodiment of the invention, it is provided that no control element exists by which the driver can predefine or select a suitable shutdown behavior or a stop operating mode with a defined shutdown behavior; that is, the selection is always made by the stop coordinator. Due to the conflict of objectives regarding the shutdown behavior between more than two possible shutdown behaviors, it can be provided that the stop coordinator is configured, depending on the available information, in particular the available operating parameters of the vehicle, to select a stop operating mode to be initiated from at least three possible stop operating modes with different shutdown behaviors and, according to the selected stop operating mode, to initiate an automatic shutdown of the drive motor to achieve the corresponding shutdown behavior.

[0015] Tests have shown that at least one identifiable shutdown behavior, in particular the different shutdown behaviors of the possible stop operating modes, can be characterized as follows: - Comfort-oriented shutdown behavior, where the drive motor is switched off as comfortably and quietly as possible. The focus here is not on rapid shutdown, but on the most comfortable shutdown of the drive motor. - Reflex start-time-oriented shutdown behavior, in which restarting the drive motor during the coast-down phase is possible for as long as possible without using a starter. This shutdown behavior is particularly suitable when a so-called change-of-mind scenario (driver wanting to continue driving) is expected or may occur. - Parking position optimized parking behavior, in which restarting the drive machine after successful shutdown of the drive machine / when the drive machine is at a standstill is possible as quickly as possible or can be carried out in an optimal manner.

[0016] In order for the stop coordinator to decide which shutdown behavior or operating mode with corresponding shutdown characteristics appears most suitable at the current time and should be initiated, the stop coordinator must have the relevant information. Advantageously, the stop coordinator is configured, based on available information describing the current driving situation of the vehicle, to identify a suitable shutdown behavior for the shutdown process, in particular to select the appropriate shutdown mode to be initiated from the possible operating modes with different shutdown characteristics.The information describing the current driving situation may include existing operating parameters of the vehicle and / or existing information about the environment (other road users, traffic flow, road class, weather, time of day) and / or existing information about the driver (behavior, attention).

[0017] In a particularly advantageous embodiment of the invention, the stop coordinator is therefore configured, depending on available information which provides information about the speed (rolling, stationary) and / or information about whether the transmission is operated with frictional or non-frictional operation, to identify a suitable shutdown behavior for the shutdown process, in particular to select a stop operating mode to be initiated from the stop operating modes with different shutdown behavior.

[0018] Similarly, when deciding on a suitable shutdown behavior, information about energy consumers in the vehicle can be taken into account; that is, the stop coordinator can be configured to identify a suitable shutdown behavior for the automatic shutdown process, taking into account at least one piece of information about auxiliary units or energy consumption of the vehicle, in particular about the current or requested operating state and / or energy consumption of at least one auxiliary unit, and in particular to select a suitable stop operating mode to be initiated from the different stop operating modes with different shutdown behaviors.

[0019] In order to achieve the identified shutdown behavior, the stop coordinator is advantageously designed to initiate or influence the parameterization of at least one of the following control and / or regulation functions, as specified for this shutdown behavior or according to the selected stop operating mode: - Crankshaft stop positioning - Function to influence the restart capability of the drive motor during the coasting phase of the drive motor, - Speed ​​reduction function, - Air volume control function, - Auxiliary unit control function, in particular function for controlling the generator and / or the air conditioning system of the motor vehicle, in particular the clutch of the air conditioning system, and / or - Function to influence comfort-oriented parking behavior.

[0020] Further advantageous embodiments of the start-stop device according to the invention also apply to the method according to the invention, which can be implemented in a suitable control unit, in particular in an engine control unit.

[0021] The invention will now be explained in more detail using an exemplary embodiment. This will show Fig. 1. A representation illustrating the conflict of objectives regarding the stopping behavior when a requirement is for the automatic shutdown of a drive motor in a motor vehicle. Fig. 2 an embodiment of a start-stop device according to the invention, with a representation of the influence of a stop coordinator on various functions to achieve an identified suitable shutdown behavior, and Fig. 3 a table to illustrate a suitable shutdown behavior based on the existing operating conditions.

[0022] The Fig. Figure 1 illustrates the conflicting objectives regarding the stopping behavior when a drive motor in a motor vehicle is required to automatically shut down. It assumes that three different shutdown behaviors can be achieved when initiating an automatic shutdown process.

[0023] The term "reflex start time" refers to a shutdown behavior oriented towards reflex start time, in which restarting the drive motor during its coasting phase should be possible for as long as possible without using a starter. This shutdown behavior is particularly suitable when a so-called change-of-mind scenario (the driver wants to continue driving) is expected or may occur.

[0024] The term "parking position" refers to a parking position-optimized parking behavior, in which the restart of the drive machine after successful shutdown of the drive machine (i.e., after the drive machine has come to a standstill) should take place as quickly or optimally as possible.

[0025] The term "stop comfort" refers to a comfort-oriented shutdown behavior, where switching off the drive motor should be as comfortable and quiet as possible. The focus here is not on a quick stop, but on the most comfortable possible shutdown of the drive motor.

[0026] Based on the Fig. 1. It is evident that there is a fundamental conflict of objectives when implementing the parking behavior. For example, if a parking behavior oriented towards reflex start time is to be achieved, a parking position-optimized or comfort-oriented parking behavior cannot be achieved simultaneously. The same applies to the implementation of any other parking behavior.

[0027] However, in order to achieve at least optimized parking behavior for every driving situation, a suitably trained start-stop coordinator should decide in advance which parking behavior should at least tend to be pursued. A "mixed decision" may also be possible.

[0028] The one in Fig. The shutdown behavior marked with 1 (a mixture of shutdown position-optimized and reflex start time-oriented shutdown behavior) is to be achieved, for example, when the drive engine, in particular a drive engine designed as an internal combustion engine, is to be automatically switched off when the vehicle is rolling, since stopping comfort plays a subordinate role when the vehicle is rolling, as the vehicle is still moving anyway and the shutdown of the drive unit is "lost" in the movement of the vehicle.

[0029] In contrast, the shutdown behavior marked with 2 (comfort-oriented shutdown behavior) should be achieved, for example, when the drive motor is automatically switched off when the vehicle is stationary, since a "smooth" shutdown is generally more important than a long reflex start time or achieving an optimal shutdown position.

[0030] The Fig. Figure 2 now shows an embodiment of a start-stop device SSE according to the invention with a representation of the influence of a stop coordinator SK on various functions to achieve an identified suitable shutdown behavior.

[0031] The start-stop system (SSE) is fundamentally designed to initiate an automatic shutdown of the engine when predefined shutdown conditions are met and no relevant shutdown preventer is present. In this example, automatic shutdown of the engine should be possible even at low speeds (e.g., below 25 km / h, below 20 km / h, or below 5 km / h). However, if not all shutdown conditions are met while the vehicle is moving, or if a shutdown preventer is present, automatic shutdown of the engine may only occur when the vehicle is stationary or near-stationary, particularly in vehicles with automatic transmissions where the brake pedal is depressed and a defined shutdown brake pressure threshold is exceeded. This is just one example, however. Numerous other scenarios are also possible.Different shutdown logics, as known from the state of the art, are conceivable.

[0032] In order to identify a suitable stopping behavior, the stop coordinator SK receives at least a speed signal v as information about the current speed of the vehicle, as well as a transmission signal gs as information about whether there is currently a power transmission or the vehicle is being operated without power transmission.

[0033] Taking these two signals v and gs into account, the stop coordinator identifies a suitable shutdown behavior for initiating a shutdown process and ensures that, at least to some extent, this identified shutdown behavior is achieved when the automatic shutdown process is initiated. To this end, the start-stop coordinator influences at least one of the following vehicle functions: - Crankshaft stop positioning - Control of auxiliary units, in particular the control of the generator and / or the air conditioning clutch, - Function to influence the starting capability of the drive motor, - Function for reducing speed, and / or - Function for air volume control.

[0034] In detail, the stop coordinator can also be configured to first determine, taking into account the two input signals v and gs, and other information relevant for triggering an automatic shutdown process (e.g., brake pedal actuation, applied brake pressure, environmental information, turn signal activation, energy consumption of auxiliary units, etc.), whether an automatic shutdown of the drive motor would be possible based on a stored shutdown logic. If one or more stop operating modes are possible, the stop coordinator SK identifies, based on the available information, the relevant stop operating mode that is possible and achieves an optimal shutdown behavior – defined or identified by the stop coordinator itself.

[0035] If the appropriate stop operating mode including the desired shutdown behavior is selected, the stop coordinator SK initiates a signal output suitable for the selection, so that the specified or identified shutdown behavior is achieved.

[0036] The Fig. Finally, Figure 3 shows a table illustrating suitable shutdown behavior based on existing operating conditions, such as those that may be stored in the Stop Coordinator SK. Three different scenarios are shown: 1. Stop to vehicle standstill with transmission power engagement, focusing on the engine shutdown position for optimal, reproducible restart of the combustion engine after the engine stop. 2. Stop in a rolling vehicle with a non-load-bearing transmission, focus on reflex starts due to a significantly increased frequency of engine stops. 3. Stop in a stationary vehicle with a non-power-locking transmission, focusing on stopping comfort

[0037] Based on the invention disclosed herein, a shutdown behavior adapted to the current operating situation can be achieved. For example, a smooth engine stop can be initiated by loading the auxiliary components and limiting the response. Conversely, in rolling vehicles, a stop with an optimal engine shutdown position and high response can be initiated.

Claims

[1] Start-stop device for initiating an automatic shutdown process of a propulsion machine in a motor vehicle, which is configured to automatically shut off the propulsion machine when predetermined shutdown conditions are met, wherein the start-stop device (SSE) comprises a stop coordinator (SK) which, based on available information (v, gs), identifies a suitable shutdown behavior for the shutdown process and, when initiating an automatic shutdown process, ensures that the identified shutdown behavior is achieved, characterized by, that the stop coordinator (SK) is set up to select a stop operating mode to be initiated from at least two stop operating modes with defined shutdown behavior, depending on the available operating parameters of the motor vehicle (v, gs), and to initiate an automatic shutdown of the drive motor in accordance with the selected stop operating mode in order to achieve the corresponding shutdown behavior. [2] Start-stop device according to claim 1, characterized in that no control element exists by which the driver can select a suitable shutdown behavior, in particular a stop operating mode with associated defined shutdown behavior. [3] Start-stop device according to any of the preceding claims, characterized by, that the stop coordinator (SK) is set up, depending on the available information, in particular the available operating parameters of the motor vehicle (v, gs), to select a stop operating mode to be initiated from at least three possible stop operating modes with different shutdown behavior and to initiate an automatic shutdown of the drive motor in accordance with the selected stop operating mode in order to achieve the corresponding shutdown behavior. [4] Start-stop device according to any of the preceding claims, characterized by , that at least one identifiable shutdown behavior, in particular a shutdown behavior of a possible stop operating mode, is characterized as follows: - Reflex start time-oriented shutdown behavior, in which restarting the drive motor during the coast-down phase of the drive motor is possible for as long as possible without the use of a starter. - Parking position optimized parking behavior, in which restarting the drive machine after successful shutdown is possible as quickly as possible. [5] Start-stop device according to any of the preceding claims, characterized by , that the stop coordinator (SK) is set up to identify a suitable shutdown behavior for the shutdown process, depending on available information (v, gs) which describes the current driving situation, in particular to select a stop operating mode to be initiated from the stop operating modes with different shutdown behavior. [6] Start-stop device according to any of the preceding claims, characterized by, that the stop coordinator (SK) is set up, depending on available information which provides information about the speed (v) and / or information (gs) about whether the transmission is operated with friction or without friction, to identify a suitable shutdown behavior for the shutdown process, in particular to select a stop operating mode to be initiated from the stop operating modes with different shutdown behavior. [7] Start-stop device according to any of the preceding claims, characterized by, that the stop coordinator (SC) is set up to identify a suitable shutdown behavior for the shutdown process, taking into account information from an auxiliary unit, in particular about the current or requested operating state and / or the energy consumption of at least one auxiliary unit, and in particular to select a stop operating mode to be initiated from the different stop operating modes with different shutdown behavior. [8] Start-stop device according to any of the preceding claims, characterized by , that the stop coordinator (SK) is configured to initiate or influence a parameterization specified for at least one of the following control and / or regulation functions according to the identified suitable shutdown behavior, in particular according to the selected stop operating mode: - Crankshaft stop position - Function to influence the restart capability of the drive motor during the coasting phase of the drive motor, - Speed ​​reduction function, - Air volume control function, - Auxiliary unit control function, in particular function for controlling the generator and / or the air conditioning system of the motor vehicle, and / or - Function to influence comfort-oriented parking behavior.

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