METHOD FOR REGULATING A PUSHING ASSISTANCE OF A VEHICLE

Description

[0001] The invention relates to a method for controlling a push assist of a vehicle, in particular a single-track vehicle such as an eBike.

[0002] The invention further relates to a vehicle, in particular a single-track vehicle such as an eBike, with a drive unit, a speed measuring device and a push assist.

[0003] Although the present invention is generally applicable to any vehicle, the present invention is described in relation to single-track vehicles in the form of e-bikes. State of the art

[0004] Single-track vehicles such as e-bikes can have a push assist function via a drive system, making it easier for a user to push the e-bike. This push assist is only activated up to a pre-set speed.

[0005] At the start of a user's push on the e-bike, the e-bike's speed is initially unknown for the following reason: Speed ​​is often measured via a reed sensor on the rear wheel. The speed can be inferred from the intervals between signals from the reed sensor. Depending on the initial position of the rear wheel, this may require up to two complete wheel rotations.

[0006] Due to the different gear ratios / transmission levels of an e-bike's drive system, the drive's rotational speed cannot be used to definitively determine the bike's speed. To prevent the walk assist from activating beyond the set speed, the system assumes the bike is in the highest gear. While this prevents the bike from accelerating beyond the set speed, it may result in insufficient walk assist. Depending on the selected gear, the e-bike's speed could therefore be significantly lower than the desired speed.

[0007] Reference is also made to the publications EP 3 915 863 A1 and DE 10 2019 115312 B3. Disclosure of the invention

[0008] In one embodiment, the present invention provides a method for controlling a push assist of a vehicle, in particular a single-track vehicle such as an e-bike, with a drive unit comprising a transmission with at least two gears and a speed measuring device, comprising the steps: Providing push assist with a first drive speed and / or torque based on a first presumed gear, determining an angle traveled by a shaft of the vehicle's drive unit since a last signal from the speed measuring device and / or since the start of push assist, presuming a second gear based on the angle traveled, and providing push assist with a second drive speed and / or torque based on the second presumed gear.

[0009] In one embodiment, the present invention provides a vehicle, in particular a single-track vehicle such as an e-bike, with a drive unit comprising a transmission with at least two gears, a speed measuring device and a push-assist device, wherein the push-assist device comprises the following: A first provisioning device, configured to provide the push assist by means of the drive unit with a first drive speed and / or a first torque based on a first presumed gear; a determination device, configured to determine an angle traveled by a shaft of the vehicle's drive unit since a last signal from the speed measuring device and / or since the start of the push assist; a guessing device, configured to guess a second gear based on the angle traveled; a second provisioning device, configured to provide the push assist by means of the drive unit with a second drive speed and / or a second torque based on the second presumed gear.

[0010] One of the advantages achieved is that the push assist can be increased even before the vehicle's speed is definitively determined. Another advantage is that the time the vehicle operates above a permissible speed for the push assist is avoided or at least reduced.

[0011] The phrase "assuming a gear" means, in particular, estimating the gear of the vehicle's transmission. For example, a gear that is plausible and not excluded in the current situation is assumed, especially the highest gear that is not excluded.

[0012] The highest gear is defined as the gear stage of the transmission that has the highest gear ratio. Conversely, the lowest gear is the gear stage of the transmission that has the lowest gear ratio.

[0013] Push assistance is defined in particular as the propulsion of the vehicle by a drive unit, wherein the drive unit has a defined drive speed that is maintained while the vehicle is being pushed by a user.

[0014] The term "angle traveled by a shaft of the drive unit" refers in particular to the angle by which a shaft or chainring of the drive unit has rotated, i.e., a fraction of a revolution of the shaft or chainring of the drive unit.

[0015] A predefinable speed is defined in particular as a speed desired by the user or a maximum speed of the vehicle.

[0016] When a user begins pushing the vehicle, the speed sensor typically cannot immediately measure the current speed. Since the preset speed up to which the push assist can be activated is limited, the push assist is only permitted to operate at a defined drive speed. The maximum permissible drive speed for the push assist therefore depends on the vehicle's current gear. The higher the current gear, the lower the maximum permissible drive speed for the push assist. To prevent exceeding the preset speed, and because the current gear is unknown at the start of the push, the system assumes the vehicle is in its highest gear.

[0017] If the vehicle's transmission were indeed in its highest gear, a new reed switch signal from the speed sensor should be measurable after a defined time, assuming the coasting assist speed is known. If this signal is absent, and the vehicle's wheel has consequently traveled a shorter distance, the vehicle's transmission cannot be in its highest gear. Therefore, the coasting assist speed can be increased, since the vehicle's transmission can only be in the second-highest gear at most. This process can be repeated indefinitely as long as no new reed switch signal is detected; that is, the angle traveled by a shaft of the drive unit is continuously measured, and gears are eliminated based on this measurement. Thus, the coasting assist can be successively increased.

[0018] Further features, advantages and further embodiments of the invention are described below or become apparent therein.

[0019] According to an advantageous embodiment of the invention, the second drive speed and / or the second torque is selected to be greater than the first drive speed and / or the first torque if the second presumed gear is lower than the first presumed gear and / or a last presumed second gear. If the second presumed gear is lower than the first presumed gear and / or a last presumed second gear, the push-assist function does not yet provide the maximum permissible assistance. Thus, the drive speed and / or the torque of the push-assist function can be increased. The advantage of this is that the push-assist function is only increased if the second presumed gear is lower than the first presumed gear, i.e., if the push-assist function actually provides insufficient assistance.

[0020] According to an advantageous embodiment of the invention, the first presumed gear is defined as the highest gear of the vehicle. This ensures that the vehicle does not accelerate beyond the predetermined speed at the beginning of the pushing process.

[0021] According to an advantageous embodiment of the invention, determining the angle traveled, presuming the second gear, and providing the push assist with the second drive speed and / or the second torque are repeated multiple times. In this way, not just one gear, but several or further gears can be successively excluded, so that the push assist can be increased earlier. The gears can also be excluded continuously.

[0022] According to an advantageous embodiment of the invention, once the vehicle reaches a target speed, the drive for the ramp assist operates at the second drive speed and / or torque until a shift event and / or gear change occurs. Upon reaching the target speed, for example, the preset speed, the ramp assist is no longer increased. Consequently, the drive speed and / or torque of the drive unit can be maintained at the current value. However, as soon as a driver changes gear, the ramp assist is no longer in the "optimal" range, meaning that it provides either too little or too much assistance. Therefore, the current assistance level can be adjusted upon detection of a shift event. The advantage of this is that the vehicle can provide suitable ramp assist over a longer period.

[0023] According to an advantageous embodiment of the invention, when a shifting event occurs, the assumption of the second gear is based on the last second gear assumed. When a shifting event occurs, i.e., a gear change takes place, the overrun assist may no longer provide the appropriate torque. In particular, when the gear is downshifted, insufficient overrun assist is provided. Since the last assumed gear is known, it can be used as the starting gear for the method. In this way, the current gear can be assumed more quickly by eliminating other gears.

[0024] According to an advantageous embodiment of the invention, the second drive speed and / or the second torque of the push-start assist drive is reduced when a gear change to a higher gear occurs. Thus, when the vehicle is shifted into a higher gear, the push-start assist may be too strong, potentially causing the vehicle to accelerate beyond the preset speed. Consequently, the push-start assist can be reduced in this case. The advantage of this is that the vehicle maintains the excessive speed for a shorter period.

[0025] According to an advantageous embodiment of the invention, the speed measuring device is provided with a reed sensor. A speed measuring device can be provided in a simple manner using a reed sensor.

[0026] Further important features and advantages of the invention will become apparent from the dependent claims, the drawings and the accompanying description of the figures.

[0027] It is understood that the aforementioned features and those to be explained below can be used not only in the combination specified, but also in other combinations or on their own.

[0028] Preferred embodiments and configurations of the present invention are shown in the drawings and are explained in more detail in the following description.

[0029] This shows Figure 1: Steps of a method according to an embodiment of the present invention; Figure 2: A diagram showing speed profiles of a vehicle according to an embodiment of the present invention; Figure 3: A diagram showing a profile of a presumed gear according to an embodiment of the present invention; and Figure 4: A vehicle according to an embodiment of the present invention.

[0030] Figure 1 shows steps of a method according to an embodiment of the present invention.

[0031] In a first step S1, a coasting assist is provided with an initial drive speed and / or torque based on a first presumed gear. The first predefined or presumed gear can correspond to the highest gear of a vehicle (not shown). The transmission amplifies the drive speed of the coasting assist by a factor that depends on the transmission gear. The vehicle's speed is therefore dependent on the current gear and the drive speed of the coasting assist. However, the gear may be unknown, meaning the vehicle's speed can only be estimated based on a presumption of the gear.By selecting the first presumed gear as the highest gear, a minimal push assist is provided which, even if the vehicle is in the highest gear, does not accelerate the vehicle beyond a predetermined speed.

[0032] In a second step S2, the angle of a shaft of the vehicle's drive unit is determined since the last signal from the speed measuring device and / or since the start of the push assist. The angle can be determined based on the current drive speed of the drive unit and the time since the last signal. For example, the angle traveled can be determined using the following equation. α t − α t 0 = ∫ t 0 t ω mot τ dτ This includes: α ( t ) The current angle α ( t 0 ) The starting angle ω mot ( τ ): The angular velocity of the motor at time τ

[0033] The angle can be determined either from the start of the sliding process or from the last reed signal.

[0034] In a third step, S3, a second gear is inferred based on the angle traveled. The second gear can be the inverse of the angle traveled. If the vehicle's current transmission gear is lower than the inferred gear, the rear wheel will travel a smaller angle than expected for each revolution of the drive unit. For example, if the drive unit completes a quarter revolution with an inferred gear ratio of 4, the wheel should complete a full revolution. However, if the wheel has completed less than a full revolution, the gear ratio must be less than 4, meaning the gear must be lower than inferred. From this, a maximum possible gear can be inferred at any given time.

[0035] In a fourth step, S4, the coasting assistance is provided with a second drive speed and / or a second torque based on the second predicted gear. If, at any point in step S3, a gear is predicted that is lower than the last predicted gear, the predictable coasting assistance is not provided. Consequently, the coasting assistance can be increased. Steps S2 to S4 can be repeated as often as desired, since a new maximum gear can be predicted at any point, and thus the drive speed or the torque of the coasting assistance can be successively increased.

[0036] Figure 2 shows a diagram with speed profiles of a vehicle according to an embodiment of the present invention.

[0037] Diagram 200 shows the early speed gain when applying the procedure according to steps S1 to S4. Figure 1The X-axis 201 shows the time in seconds and the Y-axis 202 the speed of a vehicle (not shown) in km / h. A speed measuring device in the form of a reed sensor may be mounted on the vehicle. Each time a rear wheel of the vehicle completes a full rotation, a signal can be generated by the reed sensor. The overrun process starts at time 2,0. Thus, this is also the starting point 203 for the gear selection. The reed signals 203', 203", 203"', 203ʺʺ can occur, for example, at times 3, 7; 5, 3; 6, 6 and 7, 9.

[0038] The target speed 204 can be 6 km / h. However, since the current gear is unknown, the highest possible gear is assumed. If the assumed gear is indeed the highest possible gear, but the bicycle is actually in a lower gear, the bicycle will operate at a lower speed than the preset speed. This speed is the minimum speed 205, for example, 3.8 km / h. The pushing process starts at t = 2 seconds. The actual speed 206 is the minimum speed 205. Without applying an embodiment of a method of the present invention, the speed could only be measured at the time of the second reed pulse 203, i.e., at t = 5.3 seconds, so that from this point onward, the actual speed 206 can be increased to the target speed 204.Although the actual speed of 206 is known at this point, the rotational speed cannot be increased abruptly, so even more time would elapse before the target speed of 204 would be reached.

[0039] By eliminating gears, the vehicle's highest gear can be excluded as early as time t = 3.3 seconds. Thus, the vehicle's actual speed can be increased to an intermediate speed of 4.8 km / h at this point. At time t = 5 seconds, the second-highest gear can also be excluded, allowing the actual speed to be increased to the target speed. Therefore, in the period between 3.3 and 5.0 seconds, the actual speed is higher than in the "normal case." In reality, this period is even longer, as the second Reed impulse occurs earlier than in the "normal case" due to the increased speed.

[0040] After the second reed pulse 203", the speed can be determined normally, so guessing the gear is not necessary. However, it is still possible to guess the current gear and exclude gears. For example, if a user reduces the gear while pushing, the push assist also decreases, as it is still set to the higher gear. Without the gear guessing according to the invention, two more reed pulses would be required to adjust the push assist. By continuously guessing the gear, as described above, the speed can be increased more quickly.

[0041] Figure 3 shows a diagram with a course of a presumed passage according to an embodiment of the present invention.

[0042] Diagram 300 shows the progression of the hypothesized gear 303. The x-axis 301 represents time in seconds, and the y-axis 302 represents the dimensionless gear ratio. The shifting process starts at t = 2.0 seconds. Since a reed pulse has not yet been measured, the gear is hypothesized depending on the start of the shifting process. Initially, the angle traveled by a shaft of the vehicle's drive unit (not shown) is very small. Consequently, the maximum possible gear 303 is higher than the maximum gear ratio 304 of 4. The hypothesized gear 305 is therefore initially 4. The maximum possible gear 303 is inversely dependent on the angle traveled by the drive unit's shaft and thus inversely dependent on the time elapsed since the last reed pulse. This results in the hyperbolic curve shown in Diagram 300.

[0043] From time t = 3.3 seconds, the maximum possible gear 303 is smaller than the expected gear 305, so the expected gear 305 decreases.

[0044] At time t = 3.65 seconds, a first reed switch pulse is generated. The maximum possible gear 303 is then calculated based on this first reed switch pulse and is again high. The presumed gear 305 initially remains constant until time t = 4.9 seconds, at which point the maximum possible gear 303 falls below the presumed gear 305. Consequently, the presumed gear 305 also decreases until it reaches the actual gear 307.

[0045] In diagram 300, the presumed gear 305 changes continuously, but it is also possible that the presumed gear 305 decreases in stages - for example in a transmission with fixed gear ratios.

[0046] Figure 4 shows a vehicle according to an embodiment of the present invention.

[0047] The vehicle 401, here in the form of an e-bike, comprises a drive unit 402 and a speed measuring device 403, here in the form of a reed sensor on a rear wheel 410. The drive unit 402 includes a transmission 404 with at least two gears. Furthermore, the vehicle includes a push-assist device 405. The push-assist device 405 has the following features: A first provisioning device 406, configured to provide the push assist by means of the drive unit 402 with a first drive speed and / or a first torque based on a first presumed gear; a determination device 407, configured to determine an angle traveled by a shaft of the drive unit 402 of the vehicle 401 since a last signal from the speed measuring device and / or since the start of the push assist; a guessing device 408, configured to guess a second gear based on the angle traveled; a second provisioning device 409, configured to provide the push assist by means of the drive unit 402 with a second drive speed and / or a second torque based on the second presumed gear.

[0048] The first provisioning facility 406 and the second provisioning facility 409 can be the same provisioning facility.

[0049] In summary, at least one embodiment of the present invention has at least one of the following features and / or provides at least one of the following advantages: Faster increase in the push assist of a vehicle; reduction or prevention of the time the vehicle is operated above a permissible speed.

[0050] Although the present invention has been described using preferred embodiments, it is not limited to these, but can be modified in many ways.

Claims

1. Method for regulating a pushing support of a vehicle (401), in particular a single-track vehicle (401) such as an e-bike, having a drive unit (402) that comprises a transmission (404) having at least two gears and a speed measuring apparatus (403), comprising the steps of: - providing (S1) the pushing support with a first drive speed and / or a first torque on the basis of a first presumed gear, - continuously determining (S2) an angle covered by a shaft of the drive unit (402) of the vehicle (401) since the start of the pushing support and / or since a last signal (203", 203‴, 203ʺʺ) of the speed measuring apparatus (403) and, on the basis of this, excluding gears up to a first signal (203') or further signal (203", 203"', 203"") of the speed measuring apparatus (403), - presuming (S3) a second plausible gear, which is not excluded, on the basis of the angle covered, and - providing (S4) the pushing support with a second drive speed and / or a second torque on the basis of the second presumed gear.

2. Method according to Claim 1, wherein the second drive speed and / or the second torque is selected to be greater than the first drive speed and / or the first torque if the second presumed gear is lower than the first presumed gear and / or a most recently presumed second gear.

3. Method according to either of Claims 1 and 2, wherein the first presumed gear is defined as the highest gear (304) of the vehicle (401).

4. Method according to one of Claims 1 to 3, wherein the determination (S2) of the angle covered, the presumption (S3) of the second gear and the provision (S4) of the pushing support with the second drive speed and / or the second torque are repeated multiple times.

5. Method according to one of Claims 1 to 4, wherein, when a target speed (204) of the vehicle (401) is reached, the pushing support is operated at the second drive speed and / or the second torque until a switching event and / or a gear change occur / occurs.

6. Method according to one of Claims 1 to 5, wherein, when a switching event occurs, the presumption (S3) of the second gear is based on a most recently presumed second gear.

7. Method according to one of Claims 1 to 6, wherein the second drive speed and / or the second torque of the drive of the pushing support is reduced if there is a gear change to a higher gear.

8. Method according to one of Claims 1 to 7, wherein the speed measuring apparatus (403) is provided with a reed sensor.

9. Vehicle (401), in particular a single-track vehicle such as an e-bike, having a drive unit (402) that comprises a transmission (404) having at least two gears, a speed measuring apparatus (403), and a pushing support apparatus (405), wherein the pushing support apparatus (405) comprises the following: - a first provision apparatus (406), designed to provide the pushing support with a first drive speed and / or a first torque on the basis of a first presumed gear by means of the drive unit (402), - a determination apparatus (407), designed to continuously determine an angle covered by a shaft of the drive unit (402) of the vehicle (401) since the start of the pushing support and / or since a last signal of the speed measuring apparatus (403) and, on the basis of this, exclude gears up to a first signal (203') or further signal (203", 203"', 203ʺʺ) of the speed measuring apparatus (403), - a presumption apparatus (408), designed to presume a second plausible gear, which is not excluded, on the basis of the angle covered, and - a second determination apparatus (409), designed to provide the pushing support with a second drive speed and / or a second torque on the basis of the second presumed gear by means of the drive unit (402).