Method for managing gearshifting in a gearbox
The control method optimizes engine torque reduction and recovery during gear shifts in manual gearboxes by using real-time angular position sensors to address component variations and mechanical play, enhancing driving comfort and responsiveness while minimizing emissions.
Patent Information
- Application Number
- JP2025121993
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-07-23
- Filing Date
- 2025-07-22
- Publication Date
- 2026-02-04
AI Technical Summary
Existing gear shift control methods in mobile vehicles with manual gearboxes do not adequately account for variations in component aging, user operation, and mechanical play, leading to inefficient and prolonged engine torque reduction during gear shifts, affecting driving comfort and responsiveness.
A control method that adjusts engine torque reduction and recovery based on real-time angular position sensor feedback, using predetermined thresholds to minimize torque interruption duration during gear shifts, particularly upshifts, by implementing a computerized system to manage gear shifts in mobile vehicles with manual gearboxes.
The method enhances driving comfort and responsiveness by reducing torque interruption time to the minimum necessary, improving gear shift responsiveness and reducing pollutant emissions.
Smart Images
Figure 2026017531000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a control method for managing gear shifts in a gearbox of a mobile vehicle having an engine.
[0002] The invention is particularly applicable to mobile vehicles such as motorcycles or off-road motorcycles. The mobile vehicles in question may have two wheels, three wheels, or four wheels ("quads").
[0003] The mobile vehicles to which the present invention is applied are equipped with gearboxes with manual gearshifts, i.e. the gearshifts are not automatic.
[0004] The gearbox is one that has individual gears, each with a predetermined reduction ratio, i.e. it is not a continuously variable transmission ("variator").
[0005] A mobile vehicle to which the present invention is applicable includes a gear selector shaft and an angular position sensor that provides a voltage value corresponding to the current angular position of the selector shaft.
[0006] The engine, in this case an internal combustion engine, may be a four-stroke or a two-stroke engine, and the engine may also be a one-cylinder or a two-cylinder engine, without excluding other configurations.
[0007] According to a very common arrangement, the gear shift is controlled by the driver's foot, in this case the left foot, by actuating a gear shift lever.
[0008] In this case, rapid gear shifts, especially gear shifts without declutching, are important: in practice, the driver operates the gear shift lever with his foot, without using his hand to operate the clutch control.
[0009] The advantage of fast gear shifting is particularly important for upshifts when the vehicle is accelerating.
[0010] It is known that the above-mentioned sensors can detect the start of a gear shift sequence and reduce or cancel engine torque for a predetermined period of time, in particular reducing engine speed, so that the next higher gear can be quickly and easily engaged.
[0011] Even if the above-mentioned predetermined period can be obtained from a calibration table, certain variations such as aging of components, differences in operation between several users of the vehicle, as well as the presence of certain types of play that are theoretically identical but differ from vehicle to vehicle, are not taken into account.
[0012] The inventors have attempted to improve the situation, in particular to refine the duration of engine torque reduction or cancellation to the minimum required for an upshift sequence.
[0013] For this purpose, a control method is proposed for managing an upshift in a gearbox of a mobile vehicle having an engine, the shift being intended to transition from a start gear to a target gear, the gearbox comprising a selector shaft movable between a first stable position corresponding to the start gear and a second stable position corresponding to the target gear, The gearbox includes an angular position sensor for the selected shaft that provides a voltage value corresponding to a current angular position of the selected shaft, and the method comprises: an acquiring step in which voltage values corresponding to angular positions of selected shafts are repeatedly acquired; an engine torque reduction step, in which starting from a first reference value corresponding to a first stable position of the selected shaft, the current voltage value increases and is triggered to reduce the engine torque when it becomes greater than a first predetermined threshold, the first predetermined threshold exceeding the first reference value by a first difference; an engine torque recovery step in which the engine torque reduction is cancelled and the requested engine torque is applied when the current voltage value rises above a second predetermined threshold; Including, The second predetermined threshold is less than the second reference value separated by the second difference and corresponding to a second stable position of the selected shaft.
[0014] These measures, particularly the engine torque recovery step, can shorten the duration for reducing or canceling engine torque, which is beneficial to the driving comfort of the vehicle and improves the driver's perception of responsiveness.
[0015] Reducing the shut-off time is beneficial in reducing pollutant emissions.
[0016] With the method proposed herein, the torque interruption time is adjusted to the minimum necessary.
[0017] In practice, the engine torque is reduced or cancelled as soon as the selected shaft leaves the stable position corresponding to the start gear, and conversely, the torque is restored as soon as the selected shaft approaches the stable position corresponding to the target gear.
[0018] Advantageously, there is no need to wait a predetermined period of time before restoring the requested torque, but rather it is restored as soon as the target gear is at least partially engaged.
[0019] It should be noted that the terms "first" and "second" above cover not only shifting from first gear to second gear, but also all shifting to higher gears. Thus, it is understood that the target gear is immediately above the start gear, for example, target gear R4 is immediately above start gear R3, or in another example, target gear R3 is immediately above start gear R2.
[0020] It should be noted that the concept of "torque reduction" encompasses a substantial reduction in torque or a complete cancellation of torque.
[0021] The expression "a second predetermined threshold value separated by a second difference and below a second reference value" should be understood to mean that the second predetermined threshold value is below the second reference value and the second threshold value is separated from the second reference value by a second difference.
[0022] According to one embodiment, if after the engine torque reduction step is performed the current voltage value does not reach the second predetermined threshold and returns to the first predetermined threshold again, the engine torque reduction is cancelled and the requested engine torque is applied.
[0023] In this way, if an imperfect maneuver is performed by the driver which triggers a torque cut-off, torque is restored after the originally programmed time has elapsed.
[0024] Similarly, if an object strikes the gearshift lever, moving it slightly and triggering a cutoff of the torque intended for the gearshift, normal conditions will be restored after the initially programmed time has elapsed.
[0025] It should also be noted that if the proposed strategy for shortening the torque cut-off time does not work for some reason, the predetermined period will still result in the restoration of engine torque when it has elapsed.
[0026] According to one embodiment, the first difference is in the range of 5% to 15% of the difference between the second reference value and the first reference value.
[0027] As soon as the selector shaft leaves the first stable position, this is interpreted as the start of a gearshift sequence. The first difference is small enough to allow early detection. The anticipated torque interruption also helps facilitate start gear disengagement.
[0028] According to one embodiment, the second difference is in the range of 5% to 15% of the difference between the second reference value and the first reference value.
[0029] The torque requested by the driver is restored as soon as the second reference value is approached. In practice, this means that torque is restored as soon as the target gear is at least partially engaged, in order to minimize the duration that torque is reduced or canceled. This improves the responsiveness of the system.
[0030] According to one option, the acquisition step comprises an acquisition frequency of at least 100 Hz, or even 1 kHz.
[0031] In this way, a sample of the value is provided at least every 1 ms, and it is therefore possible to advantageously respond in real time to transient sequences which may typically last tens of milliseconds.
[0032] According to one embodiment, the first stable position of the selected shaft corresponds to either the second gear ratio, or the third gear ratio, or the fourth gear ratio, and the first reference value corresponds to the second, third, and fourth gear voltages, respectively.
[0033] Therefore, the proposed method can be applied to all upshifts from first gear to highest gear.
[0034] According to one embodiment, at least the second, third and fourth gear voltages are obtained from a calibration table and adjusted by learning.
[0035] By mechanically indexing each gear position, the responsible control unit can be programmed to consider the stable voltage value as corresponding to the voltage of the engaged gear. Based on this, the control unit can adjust the value initially present in the calibration table.
[0036] It is therefore possible to take into account any particular drift in mechanical components or play that occurs with age. Initial and additional learning adjustments can also be provided from time to time.
[0037] A further object of the invention is a computer configured to implement the method defined above.
[0038] A further object of the present invention is a computer program product, preferably stored on a non-transitory storage medium, comprising instructions which, when implemented by at least one processor of a computer, perform the method defined above.
[0039] A further object of the present invention is a control system for managing an upshift in a gearbox of a mobile vehicle having an engine, the gearbox comprising a selector shaft, an angular position sensor for the selector shaft providing a voltage value corresponding to the current angular position of the selector shaft, and a gearbox gearshift lever, the control system comprising a computer configured to implement the above-mentioned method.
[0040] According to one embodiment, the gearbox gearshift lever is connected to the selection shaft by a linkage mechanism, which is external, i.e., accessible by foot, and is of the pulse type, and the linkage mechanism converts the pulse movement into a rotation of the selection shaft from a stable start position to a stable target position, which corresponds to a gear shift.
[0041] According to one embodiment, the angular position sensor is a potentiometric sensor, which is a simple and reliable solution that is easy to implement electronically.
[0042] The invention will now be explained in more detail through the description of non-limiting embodiments and on the basis of the accompanying drawings which show variants of the invention. [Brief explanation of the drawings]
[0043] [Figure 1] 1 shows a schematic representation of the area of a gear shift lever on a motorcycle. [Figure 2] 1 shows a schematic diagram of an example of a mechanism for controlling the rotation of a selection shaft in a motorcycle gearbox. [Figure 3] A gear shift timing diagram is shown. [Figure 4] 1 shows a functional diagram of a control system used in the present invention. [Figure 5] An example of a timing diagram for shifting from one gear to another, in this case between second and third gear, is shown below. [Figure 6] 10 shows another example of a timing diagram.
[0044] The same reference numbers refer to the same or similar elements throughout the various drawings. For clarity of the disclosure, some elements have not necessarily been drawn to scale.
[0045] The invention is particularly applicable to mobile vehicles such as motorcycles or off-road motorcycles. The mobile vehicles in question may have two wheels, three wheels, or four wheels ("quads").
[0046] An application to a motorcycle with a manually operated gearbox is shown.
[0047] In the example shown, the gearbox has five gears designated R1, R2, R3, R4, and R5, although the invention is of course applicable to configurations with fewer or more than five gears.
[0048] As known per se, the gearbox comprises a fork which moves a sliding gear to engage the sprocket, the position of which is controlled by a gear selector shaft 1.
[0049] According to one embodiment, an angular position sensor 2 is provided, the rotating part of which is rotatably connected to the gear selector shaft 1 and the sensor body is stationary.
[0050] The angular position sensor 2 provides a voltage value corresponding to the current angular position of the selected shaft.
[0051] Referring to FIG. 2, an angular position sensor 2 is located at the end of the selection shaft.
[0052] The angular position sensor 2 is electrically connected by electrical conductors 20 to a control unit, also called a computer, which will be described below.
[0053] The angular position sensor 2 is an analog sensor. In the example shown, the angular position sensor 2 is a potentiometric sensor. It covers an angular range close to 360°. It can also cover a smaller range.
[0054] Other types of sensors may also be used, provided that the output of the sensor resembles an analog value that takes on a number of different values depending on which gear is engaged.
[0055] The angular position sensor may be mounted on an auxiliary wheel that engages the selection shaft. Regardless of the sensor technology or sensor mounting configuration, the angular position sensor directly or indirectly provides an image of the angular position of the selection shaft.
[0056] The motorcycle is provided with a gearshift lever 3 for shifting gears in the gearbox.
[0057] The gear shift lever 3 is connected to the gear selection shaft 1 via a link mechanism 4 .
[0058] As is well known and can be seen from FIG. 1, the gear shift lever 3 is moved upwards (G-up) or downwards (G-Dn) by the driver's foot F depending on whether the driver wishes to shift to a higher or lower gear.
[0059] The gear shift lever 3 is mounted rotatably about an axis X0.
[0060] The gearshift lever 3 is of the pulse type, i.e. it returns to a rest position when not actuated by the driver's foot.
[0061] The gearshift lever 3 cooperates with the selection shaft by means of a linkage 4, a simplified version of which is shown in FIG.
[0062] The first connecting rod 41 is rotatably connected to the gear shift lever 3 and rotates about the axis X0. The second connecting rod 42 is connected to the first connecting rod 41 by a pivot connection on the axis X1. The second connecting rod 42 is provided with teeth 13 configured to engage with the pin 11.
[0063] A gear selector shaft 1 is mounted in the gearbox housing so as to be rotatable about an axis X2.
[0064] The gear selector shaft 1 comprises a pin 11 actuated by a second connecting rod 42 and an indexing recess 12 .
[0065] A third connecting rod 43 with a roller 44 indexes a specific position of the gear on the gear selection shaft 1 , the roller 44 fitting into the indexing recess 12 .
[0066] For a more complete understanding of the gear selector shaft 1 and linkage 4, the reader may refer to U.S. Pat. Nos. 3,421,384 and 4,491,031.
[0067] The gear selector shaft is sometimes referred to as a "selection drum" or a "selection barrel". The gear selector shaft 1 is provided with a substantially annular groove that allows the forks to move axially, i.e. along the axis X2, by a cam effect.
[0068] The timing diagram in Figure 3 shows the complete drive phase from zero speed, with the gearbox in neutral N, to fifth gear and back to second gear.
[0069] Specifically, the gearbox is in neutral N from start-up until time t1, first gear R1 is engaged from time t1 to time t2, second gear R2 is engaged from time t2 to time t3, third gear R3 is engaged from time t3 to time t4, fourth gear R4 is engaged from time t4 to time t5, and fifth gear R5 is engaged at time t5. Times t6, t7, and t8 correspond to downshifts (R5 → R2).
[0070] It can be seen that the voltage provided by the sensor varies in steps, with each step (VR0, VR1, VR2, VR3, VR4, VR5) corresponding to a particular angular position of the selected shaft (θN, θR1, θR2, θR3, θR4, θR5, see Figure 4).
[0071] Furthermore, each step corresponds to a particular gear in the gearbox, so that the engaged gear can be displayed at any time on the instrument panel.
[0072] In the illustrated example, the value provided by angular position sensor 2 when the gearbox is in neutral N is approximately 1.1 volts. When the gearbox is in gear R1, the voltage value VR1 is approximately 0.6 V. When the gearbox is in gear R2, the voltage value VR2 is approximately 1.7 V. When the gearbox is in gear R3, the voltage value VR3 is approximately 2.4 V. When the gearbox is in gear R4, the voltage value VR4 is approximately 3.3 V. When the gearbox is in gear R5, the voltage value VR5 is approximately 4.3 V. These reference voltages are also referred to herein as "gear voltages."
[0073] As can be seen in Figure 4, the control system involved in this case comprises a control unit 5 comprising at least a first function block 51 (acronym "Shift CTrl") responsible for shifting the gearbox gears, and a second function block 52 (acronym "Trq CTrl") responsible for calculating and applying the torque through the engine (in this case an internal combustion engine).
[0074] A control unit 5 (“computer”) continuously acquires the voltage provided by the angular position sensor 2 .
[0075] The acquisition step is performed at an acquisition frequency of at least 100 Hz, the sampling providing at least one value every 10 milliseconds for the voltage provided by the sensor.
[0076] In practice, a gear upshift without clutch disengagement typically lasts for tens of milliseconds.
[0077] 5, which provides a detailed illustration of a start gear to target gear shift, in the example shown in this case this involves a shift from second gear to third gear. Of course, this illustration applies mutatis mutandis to shifts R3 → R4, R4 → R5, R5 → R6, where applicable.
[0078] At time ta, starting from a first reference value V1 corresponding to a first stable position θ1 of the selected shaft, a second reference value V2 corresponding to a second stable position θ2 (target position) of the selected shaft is obtained at the end of the shift sequence.
[0079] If the starting gear is second gear, V1=VR2, θ1=θR2, V2=VR3, θ2=θR3. If the starting gear is third gear, V1=VR3, θ1=θR3, V2=VR4, θ2=θR4.
[0080] The proposed method includes an engine torque reduction step whereby an engine torque reduction is triggered (transition 62, OFF to ON at time tb) when the current voltage value 61 increases and becomes greater than a first predetermined threshold VS1.
[0081] For simplicity of disclosure, the Boolean torque reduction output, ie, on or off, is shown at mid-height and in the center of the timing diagram.
[0082] The first predetermined threshold V S1 exceeds the first reference value V by a first difference E S1. For example, the first difference E S1 can be selected to be in the range of 5% to 15% of the difference between the second reference value V S2 and the first reference value V S1. For example, E S1 can be on the order of 20 mV to 60 mV.
[0083] For example, in the illustrated example, the first predetermined threshold V S1 is 1.7 volts. E S1 can be selected between 5% of (V S2 - V S1) and 15% of (V S2 - V S1), for example, 10% of (V S2 - V S1).
[0084] At time td, selected shaft 1 is indexed to the position of the target gear, in this case third gear.
[0085] Advantageously, the proposed method provides an engine torque recovery step where, if the current voltage value 61 increases further and becomes greater than a second predetermined threshold value VS2, the engine torque reduction is cancelled and the requested engine torque is applied (transition 66 at time tc).
[0086] The second predetermined threshold value VS2 is less than V2. A second difference E2 separates the second reference value V2 from the second predetermined threshold value VS2.
[0087] The second difference E2 is in the range of 5% to 15% of the difference between the second reference value V2 and the first reference value V1. E2 can be selected from between 5% of (V2-V1) and 15% of (V2-V1), for example, 10% of (V2-V1).
[0088] The differences E1 and E2 can have the same or different values and can be managed in a calibration table.
[0089] FIG. 6 shows an example where the shift is not completed, but an incomplete operation is nevertheless performed by the selected shaft shifting from the idle position but not reaching the target position and returning to the starting position.
[0090] The time tg corresponds to the maximum voltage value 63 provided by the sensor during this aborted gear shift sequence. After rotation, the selector shaft returns to the starting position.
[0091] At time th, the value provided by the sensor falls below the first predetermined threshold VS1 again, at which point the engine torque reduction is canceled and the requested engine torque is applied (transition 66 at time th).
[0092] Note that in another alternative implementation, the torque recovers at time tf when the voltage value again crosses the reference value V1 (dashed line).
[0093] Note that the first, second, third, fourth, and fifth gear voltages (VR1, VR2, VR3, VR4, VR5) are obtained from a calibration table. They can be adjusted by learning in conjunction with gear position indexing as described above.
[0094] Engine torque can be momentarily cut off for a specific number of engine cycles by inhibiting the ignition command and canceling the fuel injection command.
Claims
1. 1. A control method for managing an upshift in a gearbox of a mobile vehicle having an engine, said shift intended to transition from a start gear to a target gear, comprising: The gearbox comprises a selection shaft (1) movable between a first stable position (θ1) corresponding to the start gear and a second stable position (θ2) corresponding to the target gear; The gearbox comprises an angular position sensor (2) for the selected shaft providing a voltage value (61) corresponding to the current angular position of the selected shaft, the method comprising: an acquisition step in which the voltage value corresponding to the angular position of the selected shaft is repeatedly acquired; an engine torque reduction step, in which, starting from a first reference value (V1) corresponding to the first stable position (θ1) of the selected shaft, the current voltage value increases and is triggered to reduce the engine torque when it exceeds a first predetermined threshold value (VS1), the first predetermined threshold value (VS1) exceeding the first reference value (V1) by a first difference (E1); an engine torque recovery step in which, when the current voltage value increases and becomes greater than a second predetermined threshold (VS2), the engine torque reduction is canceled and the requested engine torque is applied; Including, the second predetermined threshold (VS2) is less than a second reference value (V2) separated by a second difference (E2) and corresponding to the second stable position (θ2) of the selected shaft; method.
2. 2. The method of claim 1, wherein, after the engine torque reduction step is performed, if the current voltage value does not reach the second predetermined threshold (VS2) and returns to the first predetermined threshold (VS1) again, the engine torque reduction is canceled and the requested engine torque is applied.
3. 3. The method according to claim 1, wherein the first difference (E1) is in the range of 5% to 15% of the difference between the second reference value (V2) and the first reference value (V1).
4. 4. The method according to claim 1, wherein the second difference (E2) is in the range of 5% to 15% of the difference between the second reference value (V2) and the first reference value (V1).
5. The method of any one of claims 1 to 4, wherein the acquiring step comprises an acquisition frequency of at least 100 Hz.
6. 6. The method according to claim 1, wherein the first stable position (θ1) of the selected shaft corresponds to either the second gear ratio, the third gear ratio, or the fourth gear ratio, and the first reference value (V1) corresponds to the second, third, and fourth gear voltages (VR2, VR3, VR4), respectively.
7. 7. The method of claim 6, wherein at least the second, third and fourth gear voltages are obtained from a calibration table and adjusted by learning.
8. A computer configured to implement the method according to any one of claims 1 to 7.
9. A computer program product, preferably stored on a non-transitory storage medium, comprising instructions for performing the method of any one of claims 1 to 7 when implemented by at least one processor of said computer.
10. 8. A control system for managing upshifts in a gearbox of a mobile vehicle having an engine, the gearbox comprising a selector shaft (1), an angular position sensor (2) for the selector shaft providing a voltage value corresponding to the current angular position of the selector shaft, and a gearbox gearshift lever (3), the control system comprising a computer (5) configured to implement the method according to any one of claims 1 to 7.