GB2615112A

GB2615112A - Controlling system for controlling an electric vehicle, in particular an electric commercial vehicle

Info

Publication number: GB2615112A
Application number: GB2201127.4A
Authority: GB
Inventors: Chhuon Emery; Furtado John; Schönewolf Philipp; Kohler Thomas; Zuschlag Sabine; Kaden Lars
Original assignee: Daimler AG
Current assignee: Mercedes Benz Group AG
Priority date: 2022-01-28
Filing date: 2022-01-28
Publication date: 2023-08-02
Also published as: GB202201127D0

Abstract

A controlling system suitable for controlling an electric vehicle, the controlling system comprising a first operating element being an accelerator pedal configured to be operated by a user, a second operating element configured to be moved into different positions by the user, and a controller configured to: control an electric drive system of the vehicle to provide different positive torques for electrically driving the vehicle when moving the pedal, control the drive system to provide different negative torques for decelerating the vehicle when moving the pedal, control the drive system to provide neither a positive torque for electrically driving the vehicle nor a negative torque for decelerating the vehicle when moving the pedal into a zero point pedal position (P0), vary the P0 on the basis of a speed (v) at which the vehicle travels, and vary the smallest of the negative torques on the basis of the position of the second operation element. The second operating element may be a stalk lever.

Description

CONTROLLING SYSTEM FOR CONTROLLING AN ELECTRIC VEHICLE, IN

PARTICULAR AN ELECTRIC COMMERICAL VEHICLE

FIELD OF THE INVENTION

[0001] The invention relates to a controlling system for controlling an electric vehicle, in particular an electric commercial vehicle such as, for example, an electric truck.

BACKGROUND INFORMATION

[0002] ON 110877535 A shows a single-pedal control method for an urban low-speed following road condition of a pure electric vehicle. Furthermore, ON 109515201 A shows an electric vehicle energy recovery and control device based on an accelerator pedal signal. Furthermore, ON 109515200 A shows a vehicle and a regenerative braking control method and device of a single-pedal electric vehicle.

SUMMARY OF THE INVENTION

[0003] It is an object of the present invention to provide a controlling system by which an electric vehicle may be controlled in a particularly advantageous way.

[0004] This object is solved by a controlling system having the features of patent claim 1. Advantageous embodiments with expedient developments of the invention are indicated in the other patent claims.

[0005] The invention relates to a controlling system for controlling an electric vehicle, in particular an electric commercial vehicle such as, for example, an electric truck. In an embodiment, the controlling system may comprise a first operating element which may be an accelerator pedal. The accelerator pedal may be configured to be moved, in particular pivoted, by a user such as a driver of the electric vehicle. In an embodiment, the controlling system may comprise a second operating element, which may be a stalk lever or stalk switch, configured to be moved into different positions by said user. For example, the first and second operating elements are arranged in an interior of the electric vehicle. For example, the interior is in and/or is bound by a cabin of the electric vehicle. In a further embodiment, the second operating element may be configured as a stalk lever which may be arranged behind a steering wheel of the electric vehicle, in particular with respect to a viewing direction of the driver driving the electric vehicle. In an embodiment, the controlling system may comprise a controller, particularly a controller for power train functions. The controller may be configured to control an electric drive system of the vehicle to provide different positive torques for electrically driving the electric vehicle when moving the accelerator pedal. Moreover, the controller may be configured to control the electric drive system to provide different negative torques for decelerating the electric vehicle when moving the accelerator pedal. For example, the electric drive system is a power train or a part of a power train, wherein the power train is configured to electrically, in particularly purely electrically, drive the vehicle, such that, for example, the controller may be a controller for power train functions such that the controller may be configured to control said power train and thus the electric drive system. For example, the electric drive system may comprise at least one electric machine for electrically, in particular purely electrically, driving the vehicle. The controller may be configured to control the electric drive system to provide neither a positive torque for electrically driving the electric vehicle nor a negative torque for decelerating the electric vehicle when the accelerator pedal is in a zero point pedal position. For example, when the controller controls the electric vehicle to provide neither a positive torque nor a negative torque, the electric vehicle coasts (i.e. is in a coasting mode) when the accelerator pedal is in the zero point pedal position.

[0006] Moreover, the controller may be configured to vary (i.e. to set or adjust) the zero point pedal position on the basis of a speed at which the vehicle travels. Moreover, the controller may be configured to vary (i.e. to set or adjust) the smallest of the negative torques on the basis of the position of the second operation element (e.g. stalk switch or lever). The smallest of the negative torques is, with regard to absolute values of the negative torques, the largest negative torque (i.e. the negative torque with the largest of the absolute values of the negative torques). The smallest of the negative torques is also referred to as a peak negative torque, and the largest of the absolute values of the negative torques is also referred to as a peak negative torque value.

[0007] The invention may realize regenerative braking with the accelerator pedal. This means that an operation or mode in which at least one of the negative torques is provided by the electric drive system is also referred to as regenerative braking or recuperation since, in said operation or mode, kinetic energy of the electric vehicle is used to drive the electric drive system (i.e. the at least one electric machine) such that the electric drive system is operated as a generator or generator system. Thereby, the kinetic energy of the vehicle is converted into electrical energy provided by the electric drive system. For example, the electric energy provided by the electric drive system may be stored in a battery.

[0008] In conventional diesel trucks, an engine brake is controlled by positions of a lever on a steering wheel stalk, commanding when the accelerator pedal is disengaged. In an electric vehicle such as an electric truck, engine braking takes the form of recuperation and may greatly impact vehicle range. In order to maximize the amount of recuperated energy, it is important that a recuperation level may be modulated, and this is currently not possible with discrete engine brake requests. In addition, large swings of vehicle mass of commercial vehicles from empty to fully-loaded may require a more sophisticated recuperation strategy than is typical for electric passenger vehicles.

[0009] The present invention outlines an adaptation of the accelerator pedal, in particular a control of the accelerator pedal, to modulate a recuperation request, allowing the position of the accelerator pedal to request or command both positive and negative torques, in particular depending on a position and/or speed of the vehicle. The peak negative torque value may be defined by the position of the second operating element, for example a steering wheel stalk lever. Thus, for example, by operating the second operating element, the second operating element may be moved, in particular pivoted, into different operating element positions thereby varying or adjusting the peak negative torque value (i.e. the smallest of the negative torques). For example, the peak negative torque value may be defined by operating the position of the second operating element, in particular by the respective position of the second operating element, which the position of the accelerator pedal may modulate that command down to zero at a given position of the accelerator pedal. In an embodiment, the stalk lever may have different positions, for example three (e.g. low, medium, and high), that control the regenerative braking level.

[0010] The invention may improve engine braking control in order to encourage the driver to maximize the energy recuperated, therefore reducing energy consumption and brake wear. The invention requires no new or additional hardware and may work with any braking system and thus may be implemented in different types of vehicles.

[0011] Further advantages, features, and details of the invention derive from the following description of preferred embodiments as well as from the drawings. The features and feature combinations previously mentioned in the description as well as the features and feature combinations mentioned in the following description of the figures and/or shown in the figures alone can be employed not only in the respectively indicated combination but also in any other combination or taken alone without leaving the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The novel features and characteristic of the disclosure are set forth in the appended claims. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and together with the description, serve to explain the disclosed principles. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system and/or methods in accordance with embodiments of the present subject matter are now described below, by way of example only, and with reference to the accompanying figures.

[0013] The drawings show in: [0014] Fig. 1 shows a diagram for illustrating a controlling system for controlling an electric vehicle; [0015] Fig. 2 shows a table for illustrating the controlling system; [0016] Fig. 3 shows a further diagram for further illustrating the controlling system; [0017] Fig. 4 shows a further diagram for further illustrating the controlling system; [0018] Fig. 5 shows a further diagram for further illustrating the controlling system; [0019] Fig. 6 shows a further diagram for further illustrating the controlling system.

[0020] In the figures the same elements or elements having the same function are indicated by the same reference signs.

DETAILED DESCRIPTION

[0021] In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration". Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

[0022] While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawing and will be described in detail below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.

[0023] The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion so that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus preceded by "comprises" or "comprise" does not or do not, without more constraints, preclude the existence of other elements or additional elements in the system or method.

[0024] In the following detailed description of the embodiment of the disclosure, reference is made to the accompanying drawing that forms part hereof, and in which is shown by way of illustration a specific embodiment in which the disclosure may be practiced. This embodiment is described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.

[0025] Fig. 1 shows a diagram for illustrating a controlling system for controlling an electric vehicle. Preferably, the electric vehicle may be an electric commercial vehicle. For example, the electric commercial vehicle may be configured as an electric truck. The electric vehicle is also referred to as a vehicle. Preferably, the vehicle may comprise an electric drive system configured to purely electrically drive the vehicle. For example, the electric drive system may comprise at least one electric machine for electrically, particularly purely electrically, driving the vehicle. For example, the electric drive system may comprise several electric machines for electrically, in particular purely electrically driving the vehicle.

[0026] In an embodiment, the controlling system may comprise a first operating element which may be an accelerator pedal configured to be moved, in particular pivoted, to different positions by a user such as a driver of the electric vehicle. In an embodiment, the controlling system may comprise a second operating element configured to be operated by the user. For example, the second operating element may be a stalk switch lever. For example, the second operating element may be operated in such a way that the second operating element may be moved into different operating element positions. As will be described in greater detail below, the controlling system may allow the driver of the electric vehicle to adjust regenerative braking torque (i.e. to adjust negative torques to be provided by the electric drive system for decelerating the vehicle). Particularly, the controlling system may allow the driver to adjust regenerative braking torque using the second operating element. The respective position of the accelerator pedal may provide an additional input for the torque request. In an embodiment, the vehicle may comprise two second operating elements, in particular two stalk switches, wherein, for example, one of the two second operating elements may be used to adjust regenerative braking torque.

[0027] In an embodiment, the controlling system may comprise a controller, in particular a controller for power train functions. For example, the controller may be configured to control the electric drive system of the vehicle to provide different positive torques for electrically driving the electric vehicle when moving the accelerator pedal into first ones of the different positions. Moreover, for example, the controller may be configured to control the electric drive system to provide different negative torques for decelerating the electric vehicle when moving the accelerator pedal into different positions. Furthermore, for example the controller may be configured to control the electric drive system to provide neither a positive torque for electrically driving the vehicle nor a negative torque for decelerating the electric vehicle when the accelerator pedal is in a zero point pedal position (PO). In an embodiment, the controller may be configured to vary (i.e. set or adjust) the maximum torque on the basis of a speed at which the vehicle travels and the vehicle mass. Moreover, in an embodiment, the controller may be configured to vary (i.e. set or adjust) the smallest of the negative torques on the basis of the position of the second operating element.

[0028] For example, when providing the respective negative torque, the electric drive system is/or functions as a regenerative braking system for decelerating the vehicle, in particular in such a way that kinetic energy of the vehicle is used to drive the regenerative braking system. Thus, the electric drive system is operated as a generator or generator system by which the kinetic energy is converted into electric energy provided by the electric drive system. Thus, for example, the regenerative braking system may be controlled by the controller. For example, the controller, which may be a power train controller, and in particular an electric power train controller, may comprise a parameter to enable or disable the regenerative braking system. A mode or operation in which the electric drive system provides the respective negative torque is also referred to as recuperation or a recuperation mode since, in the recuperation mode, the kinetic energy of the vehicle is converted into electric energy thereby decelerating the vehicle. Thus, for example, the controller may comprise a parameter to enable or disable the recuperation mode. In an embodiment, a human machine interface (HMI) may be used to instruct the controller to enable or disable the regenerative braking system. The HMI may be, for example, present in a cabin of the electric vehicle, and may provide said user an option to enable or disable the regenerative braking system. In an embodiment, a default activation status of the regenerative braking system may be the last status from a rest or key cycle (e.g. status last time the vehicle was on).

[0029] The zero point pedal position (PO) is shown in the Fig. 1. As shown, PO may be a function of the speed at which the vehicle drives, wherein the speed at which the vehicles drives is also referred to as a vehicle speed. In Fig. 1, the vehicle speed is designated by v.

[0030] In an embodiment, the accelerator pedal may have a parameter that may be calibrated to set the zero point pedal position PO. For example, the parameter may be up to 30 percent of the pedal position. In other words, the PO (zero point pedal position) may be when the power train controller will request zero torque (coasting) so the vehicle may coast. In an embodiment, the power train controller may provide a zero band interval parameter based on the accelerator pedal position.

[0031] In Fig. 1, 10 designates a coasting interval which may be parameterizable. As shown in Fig. 1, the coasting interval 10 may comprise several zero point pedal positions (PO) dependent on the position of the stalk lever. Thus, said zero band interval may the coasting interval 10.

[0032] In an embodiment, if the vehicle speed is greater than a vehicle speed threshold set for maximum PO accelerator pedal position, than the PO will be equal to the PO position parameter. If the vehicle speed is less than the vehicle speed threshold for max PO position and the vehicle speed is greater than the minimum vehicle speed threshold for PO position, than the PO will be between zero and the maximum PO parameter (i.e. interpolation).

[0033] In an embodiment, the controller may provide a request for regenerative braking if the accelerator pedal position is greater than PO and the position of the second operating element is greater than a minimum position (e.g. zero). A torque request (i.e. a request for the negative torques) is dependent on the positions of the second operating element and the position of the accelerator pedal. In an embodiment, regenerative power will increase as the accelerator pedal position gets closer to zero percent. An amount of regenerative power may be determined by the position of the second operating element. In an embodiment, the controller may transition from positive torque to negative torque requests in a smooth manner based on an input from the position of the second operating element and the accelerator pedal position.

[0034] For example, regenerative braking utilizes the vehicle's electric machine as a generator to convert the kinetic energy lost when decelerating back into stored energy in the vehicle's battery. Regenerative braking may be activated via the second operating element or a service brake or the accelerator pedal. Particularly, the controlling system covers regenerative braking via the second operating element which may be configured as a torque switch and via the accelerator pedal. Inputs used to create regenerative braking torque (i.e. the respective negative torque) may be the second operating element, in particular its positions, the accelerator pedal, in particular its positions, the vehicle speed, a vehicle mass calculation, and a vehicle mass status. An output may comprise a regenerative brake torque request (i.e. a request for at least one of the negative torques to be provided by the electric drive system).

[0035] In an embodiment, a regenerative braking level may be controlled via the second operating element. There may be three levels: high, medium and low which may, for example, correspond to three different positions of the second operating element. For example, said three positions of the second operating element may be designated by 1, 2 and 3 (e.g. see Fig. 6). Regenerative braking allows the driver to maintain downhill or slow down the vehicle. In doing so, the service brakes may be avoided and some of the energy may be but back in the battery or batteries which may be configured as HV batteries.

[0036] It should be appreciated that regenerative braking levels are described and shown in the Figures (e.g. Fig. 1) in an exemplary matter, and alternative regenerative braking levels will become apparent to those of ordinary skill in the art to which the present subject matter pertains without departing from the scope thereof. For example, Fig. 1 depicts five steps: Step 1, Step 2, Step 3, Step 4, and Step 5. The five steps may be five separate positions of the second operating element which may control the regenerative braking level.

[0037] Regenerative breaking may be active if all of the requirements are met: accelerator pedal is not pressed drivetrain status is engaged position of the second operating element is broadcasting a valid position and either in the low, medium or high position [0038] In an embodiment, the max torque such as the smallest of the negative torques may be based on the input of the calculated vehicle mass and vehicle speed. In a further embodiment, the controller may communicate with a battery management system (BMS) of the electric vehicle. Particularly, the BMS may limit the amount of torque due to the battery temperature being too high, state of charge of the battery being too high, or another direct torque control (DTC) that would need to limit power in the system. For example, the battery temperature may operate between 20 degrees Celsius or higher and state of charge of the battery should not be over 75% in order for the regenerative braking system to activate.

[0039] In an embodiment, the controller may comprise a memory with a torque limit table, which may depend on the mass status of the vehicle. An example for the torque limit table is shown in Fig. 2. It should be appreciated that the torque limits displayed in the table in Fig. 2 are represented in an exemplary matter. The torque limits may vary based on the mass of the vehicle (e.g. depend on the class of the commercial vehicle).

[0040] In an embodiment, the vehicle mass may be input to the table depending on the vehicle mass status. In an embodiment, if the vehicle mass status is low or unavailable, then the vehicle mass calculation may not be used as an input to the torque limit calculated through the table. In an embodiment, if the position of the second operating element is high, then the maximum torque may be requested. For example, if the second operating element is at position medium, then 2/3 of the maximum torque may be requested. For example, if the position of the second operating element is low, then 1/3 of the max torque (maximum torque) may be requested.

[0041] In an embodiment, as shown in Fig. 3, the regenerative torque may ramp down at low vehicle speeds. Below a certain speed (i.e. some parameter speed), the torque shall be ONm. For example, the regenerative braking torque shall ramp down to zero torque when the vehicle speed is <3 mph.

[0042] For example, in order to deactivate regenerative braking via the second operating element, one of the following requirements shall be met: the accelerator pedal is pressed current gear status is neutral the position of the second operating element is not in regenerative braking position [0043] In another embodiment, the zero point pedal position (PO) is where the driver will experience zero torque (i.e. coast) at a specific pedal position. The PO at a specific pedal position shall be based on an accelerator pedal parameter threshold. Additionally, a zero band range parameter may be available to set the zero torque based on PO position. Which is shown in Fig. 4.

[0044] In a further embodiment, the PO position may be a function of vehicle speed as shown in Fig. 5 (wherein the y-axis represents pedal position and x-axis represents vehicle speed).

[0045] In an embodiment, the braking torque may be a function of the accelerator pedal position and the position of the second operating element, which be the stalk lever. The torque request may vary based on the position of the stalk lever and the accelerator pedal position as shown in Fig. 1.

[0046] In an embodiment, the torque request for regenerative braking shall increase as the accelerator pedal position gets closer to 0%. For example, the vehicle speed may be required to be above lOmph for this to occur.

[0047] In an embodiment, the driver may have access to the HMI to activate the regenerative braking feature. For example, the driver may have access to a virtual switch that may enable/disable the feature. In another example, the driver may be able to monitor the regenerative braking power percentage and/or the maximum available regenerative braking power from the vehicle's instrument cluster.

[0048] Furthermore, Fig. 6 shows the torque command (i.e. the request for negative torque) versus the position of the second operating element.

List of Reference Signs coasting interval PO zero point pedal position v vehicle speed

Claims

CLAIMSA controlling system for controlling an electric vehicle, the controlling system comprising: a first operating element being an accelerator pedal configured to be operated by a user, a second operating element configured to be moved into different positions by the user, and - a controller configured to: o control an electric drive system of the vehicle to provide different positive torques for electrically driving the electric vehicle when moving the accelerator pedal, o control the electric drive system to provide different negative torques for decelerating the electric vehicle when moving the accelerator pedal, o control the electric drive system to provide neither a positive torque for electrically driving the electric vehicle nor a negative torque for decelerating the electric vehicle when moving the accelerator pedal into a zero point pedal position (PO) , o vary the zero point pedal position (PO) on the basis of a speed (v) at which the vehicle travels, and o vary the smallest of the negative torques on the basis of the position of the second operation element.The controlling system according to claim 1, wherein the second operating element is a stalk lever.