Method for checking transmission control module in vehicles with continuously variable transmission, transmission control module, electronic control unit and vehicle

Description

1 / 9 METHOD FOR CONTROLLING THE TRANSMISSION CONTROL MODULE IN VEHICLES WITH CONTINUOUSLY VARIABLE TRANSMISSION, TRANSMISSION CONTROL MODULE, ELECTRONIC CONTROL UNIT AND VEHICLE Field of Invention

[0001] The present invention is in the field of continuously variable transmissions (CVTs). More specifically, the present invention is situated within the context of the CVT gear map for the speed limiter function. Background of the Invention

[0002] A CVT (Continuously Variable Transmission) is a type of automatic transmission that does not have fixed gears like a traditional transmission. Instead of using gears, it uses a system of pulleys and a belt (or chain) that allows continuous adjustment of the transmission ratio, changing gears progressively.

[0003] The CVT relies directly on the so-called "shiftmap" to adjust its transmission ratio. Unlike traditional automatic transmissions, which have fixed gears and well-defined shifts, the CVT works with a continuously variable ratio between the pulleys. Thus, instead of shifting gears at specific points, the CVT adjusts the position of the pulleys to offer the best transmission ratio in real time. This adjustment needs to be intelligently managed by the TCM (Transmission Control Module). The TCM is the electronic unit that manages the automatic or CVT transmission, deciding how and when to change the gear ratio to optimize performance, efficiency, and comfort; this is where the shiftmap comes into play.

[0004] The CVT transmission map functions as a pre-defined program that tells the TCM how to modify the transmission ratio under different conditions. It takes into account factors such as vehicle speed, throttle position, engine torque, and even the driving mode selected by the driver. For example, in economy driving, the transmission map adjusts the CVT to keep the engine speed as low as possible, prioritizing fuel efficiency. In sport mode, the transmission map allows the engine to operate at higher speeds for longer, providing better performance and response. Petition 870250017750, dated 06 / 03 / 2025, page 9 / 22 2 / 9

[0005] Another concept that needs to be understood is the speed limiter. The speed limiter is an electronic system that prevents the vehicle from exceeding a specified speed, whether set by the driver or defined at the factory. It does not maintain a constant speed, it only limits acceleration when the car reaches the defined limit. The system works by limiting engine torque to prevent the speed from increasing.

[0006] In the context of the speed limiter, the relationship between the CVT and the transmission map becomes even more critical. Currently, when the speed limiter is activated, control is exercised by the ECM (Engine Control Module), which reduces engine torque to maintain speed below the set limit. However, the TCM still interprets the driver's accelerator input as a signal to adjust the transmission ratio. This can result in unnecessary downshifts, causing the engine to rev unnecessarily, generating excessive noise and an uncomfortable driving experience.

[0007] Currently, there is no specific gear map for the speed limiter function. When activated, the TCM operates based on the current gear map priority, using vehicle speed and accelerator pedal input to determine the gear ratio. If the driver presses the accelerator pedal beyond a certain point, the engine limits torque to maintain the set speed, but the transmission may downshift unnecessarily, increasing engine speed.

[0008] Unlike the cruise control function (cruise conmo q) where the ECM uses a virtual pedal to smoothly manage torque and gear ratio, the speed limiter function lacks this coordination. The ECM reduces the actual torque to maintain speed, leading to a lack of communication with the TCM, which relies on the accelerator pedal signal to set the final gear ratio. These issues highlight the need for a more integrated and responsive speed limiter strategy that aligns the functions of the ECM and TCM to improve the driver experience and vehicle performance.

[0009] Currently, the CVT does not have a speed limiter transmission map. During the activation of the speed limiter function, the CVT controls the gear ratios according to the priority of the transmission map.

[0010] In the state of the art, some previous techniques have already attempted to provide solutions for Petition 870250017750, dated 06 / 03 / 2025, page 10 / 22 3 / 9 similar problems. Examples of prior art include: US9482337, US11598414, US9297455, and EP3050767.

[0011] Document US9482337 discloses a controller for a continuously variable transmission, which performs automatic vehicle speed control to control the actual vehicle speed based on a defined target speed, regardless of the amount of power required based on driver operation. According to US9482337, the electronic control unit reduces the change in the target speed ratio of the continuously variable transmission when a sensitivity coefficient is large, compared to when a sensitivity coefficient is small. When the sensitivity coefficient is large, the change in the speed ratio is suppressed, thus improving the stability of the speed ratio. When the sensitivity coefficient is small, the gear shift response is enhanced.The controller alters the degree of gear shift suppression in a continuously variable transmission in response to the sensitivity coefficient, making it possible to suppress a gear shift when necessary. In this way, it is possible to achieve both improved gear ratio stability and improved gear shift response in the vehicle's automatic speed control. US9482337, however, does not mention a gear map for the speed limiter of a vehicle with variable transmission control or the use of the difference between the current speed and the set speed as parameters.

[0012] Document US11598414 discloses a method for controlling gear changes in response to a change in driving mode. The method involves determining a maximum number of allowable low-level gear change steps based on determining the transmission state. The method then calculates the expected immediate turbine speed after the gear change for each step within the maximum allowable number of low-level changes, using the current speed of the transmission output shaft and the gear ratio of each step. This expected turbine speed is then compared to a predefined allowable speed for each step. The lowest-level gear change step among those where the expected turbine speed and the allowable speed satisfy a predefined condition is defined as the target gear change step. Finally, the method performs gear change control to reduce the current gear to the target gear change step.US11598414, however, does not mention a map of. Petition 870250017750, dated 06 / 03 / 2025, page 11 / 22 4 / 9 change the speed limiter of a vehicle with variable transmission control or the use of the difference between the current speed and the configured speed as parameters.

[0013] Document US9297455 discloses a method for modifying the default gear shift programming of a transmission for a vehicle. The method involves monitoring the vehicle's current parameters and determining road information ahead of the vehicle at a predefined distance. Future vehicle parameters are predicted based on the determined road information. The transmission's default gear shift programming is modified based on the vehicle's current parameters and the predicted future parameters. US9297455, however, does not mention a speed limiter shift map for a vehicle with variable transmission control or the use of the difference between the current speed and the set speed as parameters.

[0014] Document EP3050767 discloses a control device for a hybrid vehicle equipped with a transmission in which the gear ratio can be set according to the driver's intention. EP3050767, however, does not mention a speed limiter gear map for a vehicle with variable transmission control or the use of the difference between the current speed and the set speed as parameters.

[0015] Considering the state-of-the-art solutions, it is observed that these do not propose or suggest a gear map that properly considers the speed limiter, thus illustrating the need for new solutions on the market. Objectives of the Invention

[0016] The present invention aims to disclose a new gear map for the speed limiter function for CVT vehicles, so that only the current vehicle speed and the configured speed can be used, without the need for the engine control module to 'emulate' the corresponding request from the pedal map.

[0017] More specifically, the present invention aims to disclose a more integrated and responsive speed limiter strategy that aligns the functions of the engine control module and the transmission control module to improve the driver experience and vehicle performance. Brief Description of the Invention

[0018] The present invention discloses a method for controlling the transmission control module in vehicles with continuously variable transmission, comprising a Petition 870250017750, dated 06 / 03 / 2025, page 12 / 22 5 / 9 speed limiter gear map, where the speed limiter gear map uses the following parameters to control the gear ratio: the current vehicle speed, the desired vehicle speed, and the speed limiter function selection made by the driver.

[0019] The final gear ratio in a CVT is determined by the speeds of the primary and secondary pulleys, with the primary pulley located in the torque converter and the secondary pulley connected to the differential and consequently to the vehicle's wheels.

[0020] Through hydraulic controls, the CVT belt adjusts the speed of the primary pulley based on the speed of the secondary pulley and consequently defines the gear ratio.

[0021] One of the inputs for the control is the angular velocity of the secondary pulley, or angular velocity of the vehicle's wheels, which is measured by rotation sensors positioned on the transmission.

[0022] Preferably, the difference between the set speed and the actual speed is obtained directly by relating the measured rotation signal of the secondary pulley to the signal sent by the speed limiter system published on the vehicle's CAN network.

[0023] Preferably, the method for controlling the transmission control module in vehicles with continuously variable transmission comprises a pre-activation condition that depends on a calibrated value for the difference between the configured speed and the current vehicle speed, this calibratable value corresponding to a speed threshold to determine the TCM control input.

[0024] This value (calibratable and unique) would correspond to a speed threshold to determine the TCM control input. This value aims to prevent the so-called "hunting" of the ratio control and to function as hysteresis. It avoids the ON & OFF of the control when the vehicle is close to the configured speed and allows for a smoother transition calibration.

[0025] Preferably, the transmission control module maintains a constant engine speed when the speed limiter is active, regardless of accelerator pedal commands.

[0026] Preferably, the transmission map adjusts the gear ratio to maintain a constant engine speed.

[0027] The method for controlling the transmission control module in vehicles with Petition 870250017750, dated 06 / 03 / 2025, page 13 / 22 6 / 9 continuously variable transmission preferably allows torque variation up to a limit value of the engine torque to maintain vehicle speed below a defined value.

[0028] Preferably, the speed limit is 10km / h.

[0029] The present invention further discloses a transmission control module, comprising a method for controlling the transmission control module in vehicles with continuously variable transmission as defined by the present invention.

[0030] The present invention further discloses an electronic control unit, comprising a method for controlling the transmission control module in vehicles with continuously variable transmission as defined by the present invention.

[0031] The present invention further discloses a vehicle comprising a method for controlling the transmission control module in vehicles with continuously variable transmission and / or a transmission control module and / or an electronic control unit as defined by the present invention. Brief Description of the Drawings

[0032] The present invention will be described in more detail after the presentation of the figures, which contain a preferred configuration. The figures show: - Figure 1 illustrates a schematic representation of the behavior of torque, torque requested by the driver, pedal and engine speed, considering a situation where there is a speed limiter and a speed configured by the driver, in a vehicle using the method proposed by the present invention. - Figure 2 illustrates a schematic representation of the behavior of torque, torque requested by the driver, pedal and engine speed, considering a situation where there is a speed limiter and a speed configured by the driver, in a vehicle of the prior art. Detailed Description of the Invention

[0033] Before the invention is described in detail, it should be understood that it is not limited to the specific component parts of the apparatus described, since such components may vary. It should also be understood that the terminology used herein is only for the purpose of describing particular embodiments and is not intended to be limiting. Petition 870250017750, dated 06 / 03 / 2025, page 14 / 22 7 / 9 It should be noted that, as used in the descriptive report and appended claims, the singular forms a, an, and the include singular and / or plural referents, unless the context clearly indicates otherwise. Furthermore, it should be understood that, in the case of parameter ranges delimited by numerical values ​​being provided, the ranges are considered to include those limiting values.

[0034] It should also be understood that the modalities disclosed herein should not be understood as individual modalities that are unrelated to each other. The characteristics discussed with one modality should also be disclosed in connection with other modalities shown herein. If, in one case, a specific characteristic is not disclosed with one modality but with another, the person skilled in the art would understand that this does not necessarily mean that the characteristic is not intended to be disclosed with the other modality. The person skilled in the art would understand that the essence of this request is to disclose the characteristic also for the other modality, but that only for the sake of clarity and to keep this descriptive report to a manageable volume, this has not been done.

[0035] The present invention discloses a method for controlling the transmission control module in vehicles with continuously variable transmission, comprising a speed limiter gear map, wherein the speed limiter gear map uses as parameters to control the gear ratio: the current speed of the vehicle, the desired speed of the vehicle and the selection of the speed limiter function made by the driver.

[0036] The TCM will use the vehicle's current and desired speed, as well as the speed limiter function selection made by the driver, and based on these signals will control the gear ratio using a new speed limiter gear map. The pre-activation condition will depend on a calibrated value for the difference between the set speed and the vehicle's current speed.

[0037] This hysteresis can be a calibratable value; as an initial calibration proposal, 10 km / h could be used. In this way, when the vehicle speed reaches 10 km / h close to the configured speed, the TCM control will start operating using the speed limiter map. Similarly, if there is a small variation in the vehicle speed below the configured speed, less than 10 km / h, the transmission will continue controlling the gear ratio according to the map of the Petition 870250017750, dated 06 / 03 / 2025, page 15 / 22 8 / 9 speed limiter, preventing excessive and unnecessary transitions from one map to another.

[0038] The inputs for the transmission map will be the vehicle speed and the difference between the set speed and the current speed. With only these signals as input for the transmission map, it is possible to control the gear ratio smoothly, which can increase the efficiency of the internal combustion engine and reduce excessive engine noise.

[0039] The final gear ratio in a CVT is determined by the speeds of the primary and secondary pulleys. The primary pulley is located in the torque converter (output of the powertrain, in this case, an internal combustion engine) and the secondary pulley is connected to the differential and consequently to the vehicle's wheels. Through hydraulic controls, the CVT belt can adjust the speed of the primary pulley based on the speed of the secondary pulley and consequently define the gear ratio. Therefore, one of the inputs for control is the angular speed of the secondary pulley, or the angular speed of the vehicle's wheels, which is measured by rotation sensors positioned in the transmission. The difference between the configured speed and the actual speed is obtained directly by relating the measured rotation signal of the secondary pulley to the signal sent by the speed limiter system published on the vehicle's CAN network.

[0040] The present invention proposes a gear map for the speed limiter based on the vehicle speed and the difference between the current speed and the set speed. Using this error, the TCM can control the gear ratio to avoid unnecessary downshifts. This approach maintains a constant engine speed when the speed limiter is active, regardless of accelerator pedal commands, resulting in smoother operation and meeting driver expectations.

[0041] The present invention further discloses a transmission control module, comprising a method for controlling the transmission control module in vehicles with continuously variable transmission as defined by the present invention.

[0042] The present invention further discloses an electronic control unit, comprising a method for controlling the transmission control module in vehicles with continuously variable transmission as defined by the present invention. Petition 870250017750, dated 06 / 03 / 2025, page 16 / 22 9 / 9

[0043] The present invention further discloses a vehicle comprising a method for controlling the transmission control module in vehicles with continuously variable transmission and / or a transmission control module and / or an electronic control unit as defined by the present invention.

[0044] The present invention provides a low-cost solution, as there is no need to develop an ECU strategy, while also resolving the current inappropriate transmission-side behavior when the speed limiter function is activated.

[0045] It should be noted that the drawings presented are not necessarily to scale and are merely conceptual in nature. Nevertheless, it is expressly provided that all combinations of elements that perform the same function in substantially the same way to achieve the same results as the elements now claimed are within the scope of the present invention. Finally, it should be noted that the scope of protection of the present invention covers other possible variations, not being limited solely by the content of the claims alone, including possible equivalents. Petition 870250017750, dated 06 / 03 / 2025, page 17 / 22

Claims

1 / 2 Claims 1. A method for controlling the transmission control module in vehicles with continuously variable transmissions, characterized by comprising a speed limiter gear map; wherein, the speed limiter gear map uses as parameters to control the gear ratio: the current vehicle speed, the desired vehicle speed, and the speed limiter function selection made by the driver; wherein, the final gear ratio in the CVT is determined by the speeds of the primary and secondary pulleys, the primary pulley being located in the torque converter and the secondary pulley connected to the differential and consequently to the vehicle's wheels; wherein, by means of hydraulic controls, the CVT belt adjusts the speed of the primary pulley based on the speed of the secondary pulley and consequently defines the gear ratio;One of the inputs for the control is the angular velocity of the secondary pulley, or the angular velocity of the vehicle's wheels, which is measured by rotation sensors positioned on the transmission; and the difference between the configured speed and the actual speed is obtained directly by relating the measured rotation signal of the secondary pulley to the signal sent by the speed limiter system published on the vehicle's CAN network.

2. A method for controlling the transmission control module in vehicles with continuously variable transmissions, according to claim 1, characterized by comprising a pre-activation condition that depends on a calibrated value for the difference between the configured speed and the current speed of the vehicle; and wherein, this calibratable value corresponds to a speed threshold to determine the input of the TCM control.

3. Method for controlling the transmission control module in vehicles with continuously variable transmission, according to claim 1, characterized in that the transmission control module maintains a constant engine speed when the speed limiter is active, regardless of accelerator pedal commands.

4. Method for controlling the transmission control module in vehicles with continuously variable transmission, according to claim 1, characterized by Petition 870250017750, dated 06 / 03 / 2025, page 18 / 22 2 / 2 the transmission map adjusting the gear ratio to maintain a constant engine speed.

5. Method for controlling the transmission control module in vehicles with continuously variable transmission, according to claim 1, characterized by allowing the torque to be varied up to a limit value of the engine torque to maintain the vehicle speed below a defined value.

6. Method for controlling the transmission control module in vehicles with continuously variable transmission, according to claim 5, characterized in that the speed limit value is 10 km / h.

7. Transmission control module, characterized by comprising a method for controlling the transmission control module in vehicles with continuously variable transmission, as defined in claim 1.

8. Electronic control unit, characterized by comprising a method for controlling the transmission control module in vehicles with continuously variable transmission, as defined in claim 1.

9. Vehicle, characterized by comprising a method for controlling the transmission control module in vehicles with continuously variable transmission as defined in claim 1 and / or a transmission control module as defined in claim 7 and / or an electronic control unit as defined in claim 8. Petition 870250017750, dated 06 / 03 / 2025, pp. 19 / 22

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