Method for controlling the sailing operation of a motor vehicle

Abstract

Method for controlling a sailing operation of a motor vehicle (1) with an automated transmission (13) and / or electronically controlled clutch (12) having a throttle lever (14) configured to set both a positive and a negative desired torque (M), comprising the following steps: - Specifying (21) a desired sailing range (S) of a deflection (A) of the throttle lever (14), wherein the desired sailing range (S) begins at a deflection (A1) corresponding to a negative desired torque (M) and ends at a deflection (A2) corresponding to a positive desired torque (M), - Check (22) whether the deflection (A) of the throttle lever (14) is within the desired sailing range (S), and - Initiation (24) of sailing operation when the deflection (A) of the throttle lever (14) is in the sailing desired range (S) (23) for a period of time (t) which is greater than a predefinable time threshold (s1).

Description

[0001] The present invention relates to a method for controlling the coasting mode of a motor vehicle with an automated transmission. The motor vehicle has a throttle lever configured to set both a positive and a negative clutch engagement torque. The present invention further relates to a computer program configured to perform each step of the method according to the invention, and to a machine-readable storage medium on which the computer program according to the invention is stored. The invention also relates to an electronic control unit configured to control the coasting mode of a motor vehicle using the method according to the invention. State of the art

[0002] The operating mode of coasting, also known as "freewheeling," "high-speed free rolling," or "coasting," is a driving mode already used in current hybrid vehicles, which are designed as parallel hybrids with a disconnect clutch between the combustion engine and the electric drive motor. However, this driving mode can also be used effectively in conventional vehicles that have only a combustion engine.

[0003] During coasting, the drivetrain is disengaged, meaning the combustion engine and transmission are decoupled. Due to the lack of engine braking torque, the vehicle coasts significantly further without propulsion than with the drivetrain engaged during overrun in top gear. This saves fuel. The engine can either continue to run in idle mode (known as coasting without power) or be switched off in engine-stop mode (known as coasting without power). With the combustion engine switched off, fuel savings are further increased. Depending on the requirements and operating concept, the combustion engine restarts and re-engages automatically.

[0004] In hybrid or electric vehicles, the driver can control both acceleration and deceleration using a single pedal, the accelerator pedal. The deceleration, controlled by the electric motor via the accelerator pedal, can also be further adjusted through menu settings in the vehicle's on-board computer. For example, in Sport mode, a deceleration from a standstill can be provided by the electric motor even when the accelerator pedal is not depressed. In Eco mode, the deceleration from the electric motor can be very low or even nonexistent when the accelerator pedal is not depressed. However, since the driver must pre-configure the vehicle's deceleration behavior via menu settings, situation-specific customization of the vehicle's behavior is not possible.Under different traffic conditions and in different driving situations, the driver still desires to be able to switch between the two coasting concepts, sailing mode and engine braking, and also to be able to adjust the negative torque contribution via the electric motor using the accelerator pedal.

[0005] Furthermore, it can be provided that when the driver takes their foot off the accelerator pedal and the brake pedal is not pressed, the accelerator pedal's engagement point is set to the clutch's zero torque setting, making the transition to coasting imperceptible and comfortable for the driver. Thus, no drive torque is generated in the drivetrain or at the wheels during this transition. Overrun mode is only initiated when the driver presses the brake pedal. Some concepts stipulate that the brake pedal must be pressed for a certain threshold or duration. However, with this operating strategy, the driver cannot continuously adjust both a positive and a negative desired torque at the clutch using only one pedal.

[0006] The patent application WO 2015 / 036396 A1 describes a vehicle control system and a method for activating a coasting mode in which the powertrain is partially decoupled to reduce fuel consumption when a positive torque demand and favorable conditions such as a gradient are detected. Deactivation occurs when these conditions are no longer met.

[0007] The method known from patent application DE 10 2013 021 441 A1 regulates the slip of a clutch between the engine and transmission in more than two stages or continuously, depending on the required drag torque, at no engine load. This avoids or reduces vehicle acceleration when driving downhill without requiring a gear change, thereby improving driving comfort. The slip is set between minimum and maximum values ​​to meet the required drag torque.

[0008] German patent application DE10 2005 008 347 A1 discloses a system that determines the target torque of a vehicle based on pedal input and vehicle speed. It uses a stored three-dimensional torque surface and selects different calculation methods depending on whether the vehicle speed is below or above a creep speed threshold. A module compensates for environmental influences on the maximum torque.

[0009] German patent application DE 100 55 957 A1 describes a method that controls an automatic transmission when the accelerator pedal is suddenly released. It prevents upshifting if the pedal position gradient falls below a certain threshold. The upshift lockout is released, depending on engine torque, vehicle acceleration, and other thresholds, when traction is detected. Disclosure of the invention

[0010] The inventive method for controlling the coasting mode of a motor vehicle with an automated transmission and / or electronically controlled clutch can be implemented in a motor vehicle that has a throttle lever configured to set both a positive and a negative desired torque. According to the invention, the desired torque is understood to be a torque requested by the driver at the clutch or at the driven wheels of the motor vehicle. If the throttle lever is designed as an accelerator pedal, the desired torque is determined, in particular, from the deflection angle of the accelerator pedal.

[0011] In the method according to the invention, a desired sailing speed range is specified for a deflection of the throttle lever. The desired sailing speed range begins at a deflection corresponding to a negative desired torque and ends at a deflection corresponding to a positive desired torque. It thus includes the point of a torque-neutral deflection at which the desired torque is zero.

[0012] During the subsequent operation of the vehicle, it is checked whether the throttle position is within the desired sailing range. If this condition is met, it is further checked whether the throttle position remains within the desired sailing range for a period exceeding a predefined time threshold. If both conditions are met, sailing mode is initiated.

[0013] The time threshold is preferably chosen so that the driver can move the throttle lever from one end of the desired sailing range to the other end through the desired sailing range without unintentionally initiating sailing operation.

[0014] To provide the driver with feedback that their chosen throttle input has initiated coasting mode, it is preferred that a signal perceptible to the driver be generated when the vehicle is coasting. If the throttle is designed as an active accelerator pedal whose input can be manipulated by the vehicle's control unit, such a signal can be achieved, for example, by creating a pressure point when the throttle is moved within the desired coasting range, or by producing a vibration in the accelerator pedal during coasting. Alternatively or additionally, a visual and / or audible signal can be generated to inform the driver that coasting mode is in effect.If several different signals are generated indicating sailing operation, it is ensured with particular reliability that the driver actually perceives that the vehicle is sailing.

[0015] The method for controlling the sailing operation allows not only for initiating sailing but also for terminating it. It is preferred that sailing is terminated when the throttle lever's deflection is no longer within the desired sailing range. This allows the driver to easily end sailing by pushing the throttle lever fully or releasing it.

[0016] To achieve debouncing, it is still preferable to increase the desired sailing range after initiating sailing mode. This prevents involuntary foot movements by the driver when pressing the accelerator pedal from unintentionally ending sailing mode.

[0017] Sailing mode is preferably not terminated if the throttle lever deflection leaves the desired sailing range in the direction of a negative desired torque and the deflection gradient exceeds a gradient threshold. This allows the driver to quickly release the throttle lever so that it returns to its initial position without the vehicle exiting sailing mode. This is advantageous when sailing over a longer distance. The driver is then not forced to constantly and tiringly hold the throttle lever within the desired sailing range.

[0018] The computer program is configured to execute each step of the procedure, particularly when it runs on a computer or control unit. It enables the implementation of the procedure on a conventional control unit. For this purpose, it is stored on a machine-readable storage medium.

[0019] The electronic control unit is designed to control the sailing operation of a motor vehicle using a specific procedure. This control process takes place primarily within a sailing thrust coordinator. The control unit is created by uploading the computer program to a conventional control unit. Brief description of the drawings

[0020] An embodiment of the invention is shown in the drawings and explained in more detail in the following description. Fig. Figure 1 schematically shows various components of a motor vehicle whose sailing operation can be controlled with an embodiment of the method according to the invention. Fig. Figure 2 shows a flowchart of an embodiment of the method according to the invention. Fig. Figure 3 shows the desired sailing range in an embodiment of the method according to the invention. Exemplary embodiment of the invention

[0021] An embodiment of the method according to the invention can be used to control the sailing operation of a conventional motor vehicle 1. A schematic cross-sectional representation of such a motor vehicle 1 is shown in Fig. Figure 1 shows a vehicle 11 driven by an internal combustion engine. A clutch 12 and an automated transmission 13 are provided for transmitting the torque generated by the internal combustion engine 11 to a wheel axle 16. A throttle lever 14, designed as an accelerator pedal, is connected to an electronic control unit 15. This electronic control unit 15 controls the internal combustion engine 11 and the automated transmission 13. The throttle lever 14 is configured so that it can generate both a positive and a negative desired torque M at the clutch 12. The electronic control unit 15 controls the internal combustion engine 11 and the transmission 13 so that a torque corresponding to the desired torque M is generated at the clutch 12, at the driven wheel axle 16, and at the driven wheels 17, 18 of the vehicle 1.

[0022] After starting an embodiment of the method according to the invention, as described in Fig. Figure 2 shows a desired sail range S. This desired sail range S extends from a first deflection A1, which corresponds to a desired torque M, to a second deflection A2, which corresponds to a positive desired torque M. Fig.Figure 3 shows the relationship between the deflection A of the throttle lever 14 and the desired torque M. The first deflection A1 lies within a range 31 of a negative desired torque M, and the second deflection A2 lies within a range 32 of a positive desired torque M. After the desired coasting range S has been specified, the system continuously checks 22 whether the deflection A of the throttle lever 14 is within the desired coasting range S as the vehicle 1 continues to travel. As soon as the deflection A enters the desired coasting range S, the time t it remains within the desired coasting range S is recorded. If this time t exceeds a predefined time threshold s1 before the deflection A leaves the desired coasting range S again, it is recognized 23 that the driver of the vehicle 1 wishes to initiate coasting mode. This initiation 24 is then carried out.

[0023] As soon as the vehicle 1 is in coasting mode, a signal W perceptible to the driver is generated, indicating that coasting is in operation. For this purpose, the control unit 15 controls the throttle lever 14 so that it vibrates. It also generates a visual signal on the driver's console in the passenger compartment and alerts the driver to the coasting mode via an acoustic signal.

[0024] After initiating sailing mode, the desired sailing range S is increased. For this purpose, the first deflection A1 is shifted to a smaller value, and the second deflection A2 is shifted to a larger value. During the continued sailing operation of the vehicle 1, it is continuously checked whether the deflection A of the throttle lever 14 is still within the now increased desired sailing range S. If the driver moves the throttle lever 14 so that the deflection A leaves the desired sailing range S, it is further checked whether the desired torque M(A) specified by the deflection A is less than zero. If this condition is met, a further check 28 is performed to determine whether the gradient dA / dt of the deflection A exceeds a gradient threshold s2. If this condition is met, the vehicle 1 remains in sailing mode. Otherwise, sailing mode is terminated 29.After sailing operation has ended, the sailing request range S is redefined (21), and the two deflections A1 and A2, which limit this range, are reset to their initial values. A new monitoring process then begins to determine whether the driver wishes to initiate sailing operation again.

Claims

[1] Method for controlling a sailing operation of a motor vehicle (1) with an automated transmission (13) and / or electronically controlled clutch (12) having a throttle lever (14) configured to set both a positive and a negative desired torque (M), comprising the following steps: - Specifying (21) a desired sailing range (S) of a deflection (A) of the throttle lever (14), wherein the desired sailing range (S) begins at a deflection (A1) corresponding to a negative desired torque (M) and ends at a deflection (A2) corresponding to a positive desired torque (M), - Check (22) whether the deflection (A) of the throttle lever (14) is within the desired sailing range (S), and - Initiation (24) of sailing operation when the deflection (A) of the throttle lever (14) is in the sailing desired range (S) (23) for a period of time (t) which is greater than a predefinable time threshold (s1). [2] Method according to claim 1, characterized by , that sailing operation will be terminated (29) when the deflection (A) of the throttle lever (14) is no longer within the desired sailing range (S) (26). [3] Method according to claim 2, characterized by , that after initiating (24) the sailing operation, the sailing desired range (S) is increased (25). [4] Method according to claim 2 or 3, characterized by , that no termination (29) of the sailing operation occurs if the deflection (A) of the throttle lever (14) leaves the sailing desired range (S) in the direction of a negative desired torque (M) (27) and a gradient (dA / dt) of the deflection (A) exceeds a gradient threshold (s2) (28). [5] Method according to any one of claims 1 to 4, characterized by , that at least one signal (W) perceptible to a driver of the motor vehicle (1) is generated when the motor vehicle (1) is in sailing mode. [6] Method according to claim 5, characterized by, that a signal (W) is generated by means of the throttle lever (14). [7] Method according to claim 5 or 6, characterized by , that a visual and / or acoustic signal (W) is generated. [8] Computer program which is configured to perform each step of the method according to any one of claims 1 to 7. [9] Machine-readable storage medium on which a computer program according to claim 8 is stored. [10] Electronic control unit (15) which is configured to control the sailing operation of a motor vehicle (1) by means of a method according to any one of claims 1 to 7.

Images