Method for managing engine of vehicle to avoid urgent acceleration

Abstract

Management method for a motor vehicle, the motor vehicle comprising:-control means; -first electronic means which determine the torque demand to be provided by the motor and output a corresponding signal (TQspt); and a second electronic device for controlling the first electronic device, receiving data determined by the first electronic device, calculating a torque to be provided by the motor, and sending instructions to the first electronic device, having the following steps: deriving a torque demand (TQmod) determined by the first electronic device, -deriving the torque (TQreq) to be provided by the motor calculated by the second electronic device,-determining a difference between the two derivatives,-comparing the torque (TQspt) to be provided with a predetermined limit value (JKlim) and adjusting the torque (TQspt) to be provided in such a way that the calculated difference becomes smaller than said limit value.

Description

Technical Field

[0001] The present invention relates to a method for managing a vehicle's motor to prevent sudden acceleration (suraccélération in French), and to such vehicles. More specifically, the present invention relates to an electric motor and a vehicle driven by the electric motor (e.g., a two-wheeled vehicle such as a motorcycle; an automobile; a four-wheeled all-terrain vehicle (also known as a "quad"), etc.).

[0002] The technical field of the present invention is therefore that of motor control, more particularly for electric motor control, but also for other motor control fields such as internal combustion engines. In order to ensure that the motor operates correctly and in particular complies with safety standards, it is necessary to control various motor operating parameters, such as vehicle speed, torque provided by the motor, etc. Background Art

[0003] If the anomaly appears or disappears, the motor management system can activate or deactivate the limp home operating mode, respectively. In most cases, the limp home operating mode includes limiting the vehicle speed and / or limiting the torque provided by the motor.

[0004] In internal combustion engines, reaction times are relatively long, and therefore torque changes are relatively slow, creating an accident risk. However, with electric motors, acceleration changes can cause vehicle jerk, whether limp home mode is enabled or disabled. Due to mechanical inertia, the lower the vehicle mass, the more sensitive the driver of the vehicle is to such jerk. Therefore, the following disclosure is primarily, but by no means exclusively, intended for use in lightweight electric vehicles, such as electric motorcycles.

[0005] As a purely illustrative and non-limiting example, when a motorcycle is cold-started, its battery may reach a low charge level corresponding to a fault limit. Consequently, the motor management system will limit the motorcycle's maximum speed and / or limit the torque provided by the motor. If the driver wishes to travel faster than the imposed limits, or even accelerate more vigorously than the torque limit allows, they will tend to act on the acceleration control beyond the limit(s) imposed by the motor management system. If, at this point, for example, after a period of operation, the battery charge level rises above the lower limit, the management system switches the motor from the limp-home operating mode to its normal operating mode. Due to the position of the acceleration control, the motorcycle will therefore accelerate suddenly, which is not what the driver expected, and the driver will be surprised by this sudden acceleration.

[0006] The present invention is based on the initial observation that driving problems may arise when switching from normal mode operation to limp home mode operation or vice versa.

[0007] It is an object of the present invention to provide a device for limiting and preferably eliminating any risk of lurching of the vehicle when switching from limp home mode of operation to normal mode of operation (and / or vice versa). Summary of the Invention

[0008] According to the present invention, a method for managing a motor of a vehicle is proposed, said vehicle comprising: - means for controlling said motor via a drive; - a first electronic device which receives as input signals representative of actions on said control device and / or signals received from sensors, determines on the basis of these signals a torque demand to be provided by the motor and provides as output a torque control signal to the motor; and - a second electronic device for controlling the first electronic device; -- receiving as input the above-mentioned signal received by the first electronic device and data determined by the first electronic device; -- Calculate the torque to be provided by the motor; and -- sending instructions to the first electronic device for optionally adjusting the torque demand determined by the first electronic device so that the torque control signal output from the first electronic device corresponds to said torque to be provided by the motor; The method comprises the following steps: - calculating a first jerk (suraccélération in French) corresponding to a temporal variation of a torque demand determined by the first electronic device; - calculating a second jerk corresponding to the variation over time of the torque to be provided by the motor calculated by the second electronic means; - determining a difference between the value of the first jerk and the value of the second jerk; - comparing the difference with a predetermined limit value, and if the absolute value of the difference is smaller than the limit value, maintaining the torque control command from the second electronic device to the first electronic device, otherwise, correcting the torque control command so that the absolute value of the calculated difference becomes smaller than the limit value.

[0009] This method proposes in a novel way to analyze the curve obtained by deriving the torque curve and thus allows any changes in the torque and thus any changes in the corresponding acceleration of the vehicle to be limited. Thus, jolts and other vibrations in the vehicle can be avoided.

[0010] In the method described above, the features disclosed in the following paragraphs may optionally be implemented independently of each other or in combination with each other: - when the torque control commands are modified, they are modified so that the torque control includes a linear torque variation range that is less than the maximum variation; - The method is implemented during a transition from normal mode operation to limp home mode operation, and / or vice versa.

[0011] According to another aspect, a computer program is proposed comprising instructions for implementing the method as described above when the program is executed by a processor, in particular an electronic control unit of an internal combustion engine.

[0012] According to another aspect, a computer-readable non-volatile storage medium is provided on which such a program is stored.

[0013] According to another aspect, an electronic system for managing a motor is proposed, the electronic system being configured to implement all the steps of the above method and comprising: - Position sensors for components used to control the vehicle; - A computer equipped with electronic memory, the computer being configured to: - receiving as input data provided by a position sensor and / or data provided by other sensors; - providing instructions for carrying out the steps of the method as described above; and - Sending a command corresponding to the torque value to be provided by the motor.

[0014] According to another aspect, a motor vehicle is proposed, characterized in that it comprises an electronic system according to the preceding paragraph.Such a vehicle comprises, for example, an electric motor, which may or may not be combined with another motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Further features, details, and advantages will become apparent from reading the following detailed description and from referring to the accompanying drawings, in which: Figure 1 is a schematic diagram of a control unit architecture of the prior art; Figure 2 This invention shows that Figure 1 a schematic illustration of the actions proposed by an architecture of the type shown; Figure 3 is a graphical illustration explaining the method according to the present invention; Figure 4 is a set of curves showing the variation of various parameters during an example of implementation of the method according to the invention; Figure 5 is a schematic view of a vehicle for implementing the present invention. DETAILED DESCRIPTION

[0016] This description is provided for any motor-driven vehicle. For example, it can be a motor vehicle, a motorcycle, or a four-wheeled recreational vehicle (also known as a "quad"). The motor is, for example, but not exclusively, an electric motor. The vehicle can have a hybrid architecture (e.g., having an internal combustion engine and at least one electric motor).

[0017] Traditionally, such vehicles have at least one electronic management unit. More specifically, the electronic unit is intended to manage one or more motors. Figure 1 A known structure of a device for managing a motor in a vehicle is shown.

[0018] exist Figure 1 , the vertical hybrid line represents the boundary of an electronic control and management unit (ECU) or computer, which is located on the left side of the hybrid line and includes a first electronic device forming a first module L1 corresponding to a first control and management level and a second electronic device forming a second module L2 corresponding to a second control and management level.

[0019] The first module L1 of the first level is designed to manage the motors, while the second module L2 of the second level is designed, for safety reasons, to control the actions / commands provided by the first module L1. Thus, the first module L1 receives various information SC (input arrows), for example, from several sensors. One of these information corresponds in particular to the driver's command to the motors, which concerns the torque to be provided by the motors. In most cases, the driver's control device is the accelerator pedal, and the information provided to the first module L1 corresponds to its pedal position (PP), which indicates the torque demanded by the driver. Other information SC from various sensors (such as pressure and temperature) serves as additional inputs to the first module L1. Finally, after control by the second module L2, the first module L1 outputs a control signal SM to the motors.

[0020] The second module L2 performs control by receiving information (not necessarily all information) received by the first module L1, particularly the position PP of the accelerator pedal (or equivalent: for example, the throttle on a two-wheeled vehicle). It also receives data from the first module L1, more specifically data to be controlled. In turn, the first module L1 receives confirmation of the data provided by the first module L1 and / or instructions from the second module L2, such as switching to a limp-home operating mode or returning to normal operating mode. Several limp-home operating modes are possible, for example, modes that limit vehicle speed or even the torque provided by the motor.

[0021] External control is also provided, thereby creating a third level of control and management. This third electronic device, forming the third electronic module L3, is physically located outside the electronic control and management unit (ECU) and controls the operation of the first and second modules L1 and L2. To achieve this control, the third module L3 at the third level exchanges data with the second module L2. The second module L2 can request the third module L3 to stop the motor or even reset the ECU. If necessary, the motor stop (STOP) and / or reset of the electronic control and management unit (ECU) are controlled by the third module L3. This third module L3 at the third level thus controls the operation of the second module L2 at the second level and the proper operation of the first module L1 at the first level (memory and computer).

[0022] This general architecture is known to those skilled in the art and may vary according to the manufacturer, but in most cases, for safety reasons, there are two levels of control for a first module L1 which receives information and / or instructions and processes them in order to send instructions to the motor associated with said module, such as the torque value to be provided.

[0023] Figure 2 Shows the same functionality Figure 1 In this case, it should be noted that a module L1' is added, which is schematically shown as a separate module to better explain the interaction proposed by this specification, but this module can be physically integrated into the second module L2. In this case, module L1' can be considered as a software element arranged between the first module L1 and the second module L2, rather than a separate hardware element.

[0024] In a completely novel manner, the invention proposes to control any variation in acceleration in order to prevent the vehicle from jolting while driving, or in other words, from vibrating or pitching.

[0025] Figure 2 The schematic diagram of shows that the second module L2 sends a torque curve provided by it for controlling the motor to the module L1 ′. Based on this torque curve, the module L1 ′ determines a first jerk curve corresponding to the derivative of the torque curve.

[0026] While determining the jerk, the module L1 ′ will determine a second jerk profile based on the command (PP) provided by the driver, this second jerk profile corresponding to the derivative of the torque profile defined by the first module L1 .

[0027] The idea is then to compare the orders received from the driver through their action on the control means (accelerator pedal, rotary handle, joystick, etc.); and the orders that the second module L2 has verified as valid or has modified in order to send them to the motor via the first module L1, and to see if these orders correspond or if they are "significantly different" from each other. In this case, the comparison is not made on the torque curve, but on the jerk curve, i.e. the curve obtained by differentiating the torque curve under consideration. If the variation is too great, i.e. exceeds a predetermined value, the torque curve provided by the second module L2 is adjusted by the module L1' so that the motor is controlled smoothly, without jerks or jolts.

[0028] The method is illustrated in more detail in Figure 3 and Figure 4 .

[0029] Figure 3 A "block" is illustrated in which the orders provided by the driver (PP) are taken as input and the torque to be provided by the motor (TQ_spt) as output. Within said block a subset is identified which corresponds to the proposed contribution of the present invention with respect to the management systems known in the prior art.

[0030] A first level (software) function FL1 will determine, on the basis of, for example, the orders corresponding to the position of the accelerator pedal (PP), a demand torque curve which corresponds in terms of torque to the demand of the driver when said driver acts on the accelerator pedal (hereinafter it is assumed that the control means available to the driver is the accelerator pedal, but any other means operates in a similar manner). If for various reasons the motor has to adopt a limp-home operating mode, the curve corresponding to the torque setpoint should be modified. This leads in turn to a modified torque curve TQ_mod which, for example, corresponds to the demand torque curve but for which, during an operating time period, the torque will be limited to the value TQ_lim.

[0031] A second level (software) function FL2 also calculates a corresponding torque curve on the basis of the same data PP.

[0032] The present invention proposes that the modified torque curve TQ_mod and the demand torque curve TQ_req (calculated by the function FL2) are differentiated with respect to time (operation d / dt). The results obtained by these two differentiation operations are introduced into a comparator (+ / -) which provides a difference value, the absolute value abs of which is considered. This absolute value is compared with a predetermined value JK_lim. These operations are illustrated in Figure 3This is schematically shown in the area enclosed by the dashed line in FIG. If the absolute value abs remains below JK_lim, a modified torque curve TQ_mod corresponding to the demand torque curve calculated by function FL2 is validated and becomes the torque curve TQ_spt, which corresponds to the torque command provided to the motor. However, if the absolute value abs exceeds the value JK_lim, the command torque curve TQ_mod provided by function FL1 is modified so that torque variations in this curve are attenuated.

[0033] Figure 4 The above method is illustrated with illustrative graphs.

[0034] The first curve PP shows the variation in accelerator pedal position. By depressing the accelerator pedal, the driver provides instructions to the vehicle's motors, indicating whether they wish the vehicle to travel faster or slower. In this way, they manage the vehicle's acceleration. This is correlated with the torque delivered to the wheels. This torque essentially corresponds to the torque provided by the motor or motors in the closest gear ratio (in this case, it may also include a gear efficiency that is always less than 1). Thus, it can be seen that motor torque is correlated with vehicle acceleration, and the present invention proposes operating based on motor torque, as this is the quantity typically used to manage the motors. However, in theory, other torque quantities (such as the torque at the wheels) or vehicle acceleration could also be considered.

[0035] The curve Tq_req corresponds to the conversion of the driver's action on the accelerator pedal into torque. In order to accelerate the vehicle, as shown by the curve PP providing the accelerator pedal position, the motor considered to move the vehicle must provide a torque according to the demand torque curve TQ_req shown.

[0036] The modified torque curve TQ_mod assumes that, for a period of time, the function FL1 has determined that the motor should be operated in limp home mode and that the torque provided by the motor cannot exceed a value TQ_lim (e.g. Figure 3 shown).

[0037] The curve obtained by differentiating TQ_req and TQ_mod is calculated. The curve obtained by differentiating TQ_req is not shown, but it can be seen from the curve Tq_req that the torque changes are limited and very gradual. The jerk (i.e., the derivative of acceleration, or in this case, the derivative of torque, which is equivalent) is almost zero.

[0038] The curve J1 itself shows the variation of the correction torque TQ_mod. It can be seen that in this case the jerk provided by J1 has a significant negative value corresponding to limiting the torque to torque TQ_lim and then has a significant positive value as the torque demand changes suddenly from value Tq_lim to a higher torque value.

[0039] Jerk curve J1 is then modified to curve J2. Since curve Tq_mod corresponds to curve Tq_req, where the torque is locally limited to TQ_lim, curve J2 corresponds, for example, to curve J1, where the jerk value is limited to JK_lim. Thus, the peak of J1 is replaced by a horizontal portion with an absolute value of JK_lim, or preferably even a value less than JK_lim (e.g., JK_lim*0.9 or even JK_lim*0.5).

[0040] By integrating the curve J2, the torque curve TQ_spt to be provided is obtained, determined by the module L1 ′ and supplied to the first module L1, which in turn transmits a torque command to the motor via the signal SM. It should be noted that when the jerk value is limited to a limit value (JK_lim or a fraction thereof), the torque value develops linearly, and the acceleration of the vehicle is therefore gradual, without jerks or jolts.

[0041] The above method is preferably implemented by an electronic unit on board a vehicle, for example a motor vehicle. The electronic unit corresponds to an electronic control and management unit ECU, also called CPU. Figure 5 Schematically shown is a vehicle V driven by a motor M, wherein said motor is electronically controlled by at least one electronic unit CPU. For example, the motor M is an electric motor.

[0042] Industrial Applications This technical solution is particularly applicable to motor control. More specifically, it is intended to control one or more electric motors, which may or may not be connected to an internal combustion engine, but it can also be more generally applied to control any motor. In practice, any torque change in an internal combustion engine is slower than in an electric motor due to its inertia when changing its torque.

[0043] In a completely novel approach, this paper aims to control sudden acceleration. This allows for improved vehicle driving comfort. This improvement is even more pronounced when the vehicle is lightweight. In fact, the vehicle's mass increases its inertia, and changes in acceleration are partially "absorbed" by the vehicle's mass.

[0044] As explained in the present invention, the additional control introduced herein does not require the presence of new sensors and can be performed by software, without modifying the structure of the electronic control and management unit.

[0045] The present invention is not limited to the embodiments and alternative embodiments presented above, which are provided as examples only, but the present invention includes all alternative embodiments that a person skilled in the art can think of within the intended scope of protection.

Claims

1. A method for managing a motor of a vehicle, the vehicle comprising: - means for controlling said motor via a drive; - a first electronic device (L1) which receives as input a signal (PP) representative of an action on said control device and / or a signal (SC) received from a sensor, determines on the basis of these signals a torque demand (TQ_req) to be provided by said motor, and provides as output a torque control signal (TQ_spt) to said motor; and - a second electronic device (L2) for controlling said first electronic device (L1); - receiving as input the aforementioned signal (PP) received by said first electronic device (L1) and data determined by said first electronic device (L1); - calculation of the torque to be provided by the motor (TQ_mod), the torque being limited to a value TQ_lim during operation of the motor in limp-home mode; and - sending instructions to the first electronic device (L1) for optionally adjusting the torque demand determined by the first electronic device (L1) so that the torque control signal (TQ_spt) output from the first electronic device (L1) corresponds to the torque (TQ_mod) to be provided by the motor; The method comprises the following steps: - calculating a first jerk corresponding to a variation over time of a torque demand (TQ_req) determined by the first electronic device (L1); - calculating a second jerk corresponding to the variation over time of the torque (TQ_mod) to be provided by the motor, calculated by the second electronic means (L2); - determining a difference between the value of the first jerk and the value of the second jerk; - comparing the difference with a predetermined limit value (JK_lim), and if the absolute value of the difference is smaller than the limit value, maintaining the torque control command from the second electronic device to the first electronic device, otherwise, correcting the torque control command so that the absolute value of the calculated difference becomes smaller than the limit value.

2. The method according to claim 1, characterized in that When the torque control commands are modified, they are modified so that the torque control (TQ_spt) includes a linear torque variation range that is less than the maximum variation.

3. The method according to claim 1 or 2, characterized in that The method is implemented during a transition from normal mode operation to limp home mode operation, and / or vice versa.

4. An electronic system for managing a motor, the electronic system being configured to implement all the steps of the method according to any one of claims 1 to 3 and comprising: - Position sensors for components used to control the vehicle; - a computer (ECU) equipped with an electronic memory, said computer being configured to: - receiving as input data provided by said position sensor (PP) and / or data provided by other sensors; - providing instructions for implementing the steps of the method according to any one of claims 1 to 3; and - Sending a command corresponding to the torque value (TQ_spt) to be provided by the motor.

5. A computer program comprising instructions which, when said program is executed by a computer, cause said computer to carry out all the steps of the method according to any one of claims 1 to 3.

6. A non-transitory computer-readable recording medium, characterized in that The computer program according to claim 5 is stored on the medium.

7. A vehicle, characterized in that: The vehicle comprises the electronic system according to claim 5 .

8. The vehicle according to claim 6, characterized in that It comprises at least one electric motor.

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