Method for detecting the release of a brake actuation element of a motorcycle and electronically controlled braking system of a motorcycle

Abstract

Method for detecting when a brake actuation element (3, 5) of a motorcycle is released by the rider, wherein the motorcycle comprises an electronically controlled braking system with at least one brake pressure control function, wherein, during a brake pressure control (30) carried out by the brake pressure control function, successive values ​​of at least one vehicle dynamic parameter (X, a, v) are displayed. R, a R ) determined, and at least partially stored, and - by comparing a current value (a aktuell , v R ) the parameter with a comparison value (a max , v R max ), and / or - from the time course of the values ​​of the parameter (a R ) It is detected (31) whether the driver has released a brake actuation element (3, 5), whereby the vehicle dynamics parameter is a vehicle deceleration (a) or a wheel rotation speed (v). R ) or a wheel rotation acceleration (aR ) is characterized in that the brake actuation element (3, 5) can be released by the driver - based on a decrease in the amount of vehicle deceleration (a), and / or - based on the magnitude of a decrease in wheel rotational speed (v) R ), and / or - from a vibration behavior of the wheel rotational acceleration (a R ) is recognized wherein the braking system does not have a sensor to detect an actuation by the driver of a brake actuation element (3, 5) assigned to a brake circuit (1, 2).

Description

[0001] The invention relates to a method according to the preamble of claim 1 and to an electronically controlled braking system according to the preamble of claim 18.

[0002] Over the past few decades, the motorcycle has evolved from a cost-effective means of transportation to a leisure vehicle, where both the safety and comfort of the rider are increasingly emphasized.

[0003] Traditionally, motorcycles have a separate control for each of the two brake circuits. The front brake is usually operated by a "hand brake lever" and the rear brake by a "foot brake lever".

[0004] Similar to automobiles a few years ago, motorcycles are increasingly being equipped with anti-lock braking systems (ABS). For example, German patent DE 10 2005 003 774 A1 discloses a motorcycle braking system with anti-lock braking for both the front and rear brake circuits. This system also includes an integrated braking function, whereby when the front brake circuit is actuated by a handbrake lever, the rear brake is also activated by actively building up pressure. To measure the master cylinder pressure (also referred to as pre-charge pressure or brake actuation pressure) supplied to the front brake circuit, the system includes a first pressure sensor and a second pressure sensor for redundant measurement of the master cylinder pressure. The first pressure sensor, located between the inlet valve and the master cylinder, allows the rider to easily detect a decrease in pre-charge pressure.

[0005] For example, DE 10 2008 042 297 A1 describes a control unit and a control procedure for a vehicle braking device, in particular an anti-lock braking system of a motorcycle.

[0006] From DE 10 2006 021 186 A1 a method for detecting an emergency braking maneuver and adjusting the brake force distribution of an integral braking system is known.

[0007] The invention is based on the objective of providing a method and a braking system for detecting a release process of a brake actuation element by a driver, which / in which the release of the brake actuation element is detected indirectly, without utilizing a sensor for measuring the actuation of the brake actuation element, such as a (brake actuation) pressure sensor, lever travel sensor or similar.

[0008] This problem is solved according to the invention by the method according to claim 1 and the braking system according to claim 18.

[0009] According to the invention, the term "releasing a brake actuating element" is understood to mean a reduction in the brake actuating pressure, which then corresponds to a reduction in the master brake cylinder pressure or pre-pressure in a wheel brake circuit belonging to the brake actuating element.

[0010] Advantageously, the inventive method or braking system detects whether the rider has released the brake actuating element during a brake pressure regulation operation carried out by a brake pressure control function, in particular an anti-lock braking system and / or a rear wheel lift prevention function. This is because releasing a brake actuating element during brake pressure regulation, especially if the brake actuating element is subsequently re-engaged, can negatively affect the feel of the brake actuating element, impacting the rider's perceived sense of safety. Furthermore, under-braking of the motorcycle can occur during brake pressure regulation if the actual pre-pressure (after releasing the brake actuating element) deviates from the pre-pressure assumed by the braking system, which is incorporated into the brake pressure regulation, due to an undetected release process.

[0011] It is also preferred that it be detected whether the driver has released the brake actuator beyond a predetermined amount. It is particularly preferred that it be detected whether the driver has released the brake actuator beyond a certain amount such that the pre-pressure is approximately equal to or less than the wheel brake pressure assumed by the brake pressure control function, e.g., calculated using a pressure model.

[0012] The method according to the invention is advantageously carried out to detect a release of the brake actuation element (usually handbrake lever) which is assigned to the front wheel brake circuit of the motorcycle, since the actuation feel of the handbrake lever is particularly important for the driver's sense of safety.

[0013] The invention also relates to a braking system of a motorcycle, in particular with an anti-lock braking function, in which a method according to the invention is carried out.

[0014] One advantage of the invention is that it eliminates the need for sensors to measure the actuation of the brake actuator, thus reducing the manufacturing costs of a motorcycle. Furthermore, the inventive method reliably detects a release process in brake systems without corresponding sensors, or even in brake systems with corresponding sensors if the sensors fail, and allows this to be taken into account during brake pressure regulation, resulting in improved braking performance. Another advantage of the invention is that the rider's feel for the brake actuator, and therefore their sense of safety, is enhanced by the reliable detection and consideration of a release process, particularly if the rider releases and then re-engages the brake actuator, especially the handbrake lever, during brake pressure regulation.

[0015] Further preferred embodiments of the invention will become apparent from the dependent claims and the following description with reference to figures.

[0016] They show schematically Fig. 1. A first exemplary braking system for a motorcycle, Fig. 2 a second exemplary braking system for a motorcycle, Fig. 3 exemplary pressure profiles during brake pressure regulation according to the state of the art, Fig. 4 a flowchart of a first embodiment of a method according to the invention, Fig. 5 an example of solution detection according to a second embodiment of a method according to the invention, Fig. 6 an example of solution detection according to a third embodiment of a method according to the invention, Fig. 7 exemplary curves of wheel speed and wheel acceleration, and Fig. 8 exemplary pressure profiles during brake pressure control according to a sixth embodiment of a method according to the invention.

[0017] Fig. Figure 1 schematically shows an exemplary motorcycle braking system for carrying out a method according to the invention. The braking system consists of a hydraulically actuated front wheel and rear wheel brake circuit 1, 2, with a master brake cylinder 4 connected to the front wheel brake circuit 1 and actuated by a hand brake lever 3, and a master brake cylinder 6 connected to the rear wheel brake circuit 2 and actuated by a foot brake lever 5.

[0018] For brake slip control, electromagnetically actuated inlet and outlet valves 7, 8 are used in both the front and rear brake circuits 1, 2. The inlet valve 7, which is open in its normal position, is installed in the brake line of the respective front or rear brake circuit 1, 2, which connects the corresponding master brake cylinder 4, 6 to the front or rear brake 9, 10. The outlet valve 8, which is closed in its normal position, is installed in a return line 11 of each brake circuit. This return line connects the front or rear brake 9, 10 to a low-pressure accumulator 12 and the suction side of a dual-circuit pump 13, which operates on the return pumping principle. The pump 13 is connected to the brake lines 15 via noise-dampening chambers 14 installed in both brake circuits, ensuring demand-based return of the fluid supplied by the front or rear brake 9, 10.Rear wheel brake 9, 10 drained brake fluid volume is ensured.

[0019] The inlet valves 7 allow the brake pressure generated in the brake lines 15 of the dual-circuit brake system to be limited at any time. The brake pressure reduction in the wheel brakes 9, 10 occurs via the electromagnetically actuated outlet valves 8 towards the two low-pressure accumulators 12.

[0020] The control unit 16 (ECU: Electronic Control Unit), which, for example, controls the valves 7, 8 and the pump 13, forms an integral part of a brake unit 17. It is preferably plugged into the inlet and outlet valves 7, 8 integrated into the brake unit 17 for electrical contact. Due to its particularly compact design, the brake unit 17 can therefore be mounted near a battery on a motorcycle frame.

[0021] The exemplary braking system is designed to implement an anti-lock braking system (ABS). A tendency for the front wheel (VR) or rear wheel (HR) to lock is detected by means of wheel speed sensors (not shown) and their signal evaluation in the control unit 16. The inlet valve 7, located in the front wheel or rear wheel brake circuit 1, 2, is closed electromagnetically by the control unit 16 to prevent a further build-up of the wheel brake pressure p. R to prevent in the front or rear wheel brake 9, 10.

[0022] Should further pressure reduction in the front or rear wheel brake 9, 10 be necessary to reduce the tendency to lock up, this is achieved by opening the normally closed exhaust valve 8, which is connected to the low-pressure accumulator 12. The exhaust valve 8 closes as soon as the wheel acceleration again exceeds a certain level. During the pressure reduction phase, the corresponding inlet valve 7 remains closed, so that the master cylinder pressure p generated in the front or rear wheel brake circuit 1, 2 VD (Driver form) cannot be propagated to the front or rear wheel brake 9, 10.

[0023] If the measured slip values ​​allow pressure to build up again in the front or rear wheel brake 9, 10, the inlet valve 7 is opened for a limited time according to the requirements of the brake pressure control function integrated in the control unit 16, e.g., the slip regulator. The hydraulic volume required for pressure build-up is supplied by the pump 13.

[0024] The exemplary brake system described above does not include pressure sensors, e.g., for measuring a driver's pre-pressure p. VD , or other sensors for detecting the actuation of a brake actuation element 3, 5.

[0025] The method according to the invention is preferably also implemented in brake systems with at least one pre-pressure sensor or other sensor technology for detecting the actuation of a brake actuation element. The method according to the invention is carried out when the sensor technology is faulty and / or to verify the plausibility of the sensor-detected data.

[0026] Fig. Figure 2 schematically shows another exemplary motorcycle braking system for carrying out a method according to the invention. It is a fully integrated braking system for a motorcycle. First, the components of the braking system are described. Fig. 1 corresponds to. The braking system consists of two brake circuits 1', 2', one for the front wheel VR and one for the rear wheel HR, each with a master brake cylinder 4', 6'. The rider directly operates the front wheel brake 9' with a handbrake lever 3' and the rear wheel brake 10' directly with a foot pedal 5'.

[0027] For brake slip control, electromagnetically actuated inlet and outlet valves 7', 8' are arranged in both the front and rear brake circuits 1', 2'. An inlet valve 7', open in its normal position, is installed in the brake line of each of the front and rear brake circuits 1', 2', which connects the respective master cylinder 4', 6' to the front or rear brake 9', 10'. The outlet valve 8', closed in its normal position, is installed in a return line 11' of each brake circuit, which connects the front or rear brake 9', 10' to a low-pressure accumulator 12' and the suction path 19' of a dual-circuit pump 13', operating on the return pump principle. The pump 13' is connected on the pressure side to the brake lines 15' of both brake circuits, so that in a brake slip control phase, the return of the fluid from the front or rear brakes is carried out as required.The rear wheel brake 9', 10' ensures that the drained brake fluid volume is supplied to the brake lines 15' of both brake circuits. The pump pistons of the two pump circuits are driven jointly by an electric motor 18'.

[0028] Unlike the braking system from Fig. 1 The fully integral braking system has in each brake circuit 1', 2' an additional isolating valve 101 which is open in the basic position and a switching valve 100 which is closed in the basic position.

[0029] Both brake circuits 1' and 2' can be operated together or independently, according to their circuit design. When the master brake cylinder 4' connected to the front brake circuit 1' is manually actuated, not only is brake pressure built up in the front brake 9', but simultaneously, electro-hydraulic brake pressure is built up in the rear brake 10'. This occurs because the electric motor 18' activates the pump 13' as soon as the pump 13' draws hydraulic fluid from the master brake cylinder 6' and delivers it to the rear brake 10', as a result of the electrically initiated opening of the changeover valve 100 in the rear brake circuit 2'. Meanwhile, the isolating valve 101 in the rear brake circuit 2' isolates the pump pressure side from the master brake cylinder 6'. Accordingly, depending on the manual actuation of the master brake cylinder 6' connected to the rear wheel brake 2', an electro-hydraulically initiated braking action is triggered on the front wheel brake 9' according to the same scheme.It follows that for the fully integrated braking system made of . Fig. 2 when one of the two master brake cylinders 4', 6' is actuated, the brake circuit not actuated by the driver is pressurized by the dual-circuit pump 13' in a quasi electro-hydraulic manner, so that when one of the two master brake cylinders 4', 6' is actuated individually, both brake circuits always contribute to the braking deceleration.

[0030] To measure the master brake cylinder pressure p introduced into brake circuit 1', 2' by the respective master brake cylinder 4', 6' VD (Driver's pre-print) pressure sensors 102 are generally used. For analog control of the inlet valves 7', the brake circuits 1', 2' can additionally be equipped with a wheel brake pressure p. R The sensors are equipped with pressure sensors 103. The pressure sensor signals are evaluated by a logic circuit in an electronic control unit 16'.

[0031] If a malfunction occurs in the exemplary fully integrated braking system, e.g., due to the failure of one of the pressure sensors 102 or 103, the switching and isolating valves 100 and 101 are no longer controlled / switched for safety reasons. The fully integrated braking system then essentially corresponds (open isolating valve 101, closed switching valve 100) to the braking system described in [reference to relevant document]. Fig. 1. The inventive method for detecting a release of a brake actuation lever during brake pressure regulation is then preferably carried out instead of evaluating the pressure sensor signals 102 or 103.

[0032] Alternatively or additionally, a braking system according to the invention can include, besides an anti-lock braking function, a rear wheel lift detection system with brake pressure control to prevent or suppress rear wheel lift. Rear wheel lift can occur, for example, during hard braking, due to the dynamic axle load distribution to the front axle (front wheel) during the braking process. By evaluating various pieces of information, such as the wheel speed signals, an incipient rear wheel lift can be detected. The lift detection is preferably performed in control unit 16, 16'. If rear wheel lift is detected, the brake pressure in the front wheel brake 9, 9' is maintained or even reduced, for example, to decrease the vehicle deceleration and thus bring the rear wheel HR back into contact with the ground or increase the ground contact. The control of the intake and exhaust valves 6, 7, 6', 7' is performed by control unit 16, 16'.Pressure maintenance, pressure reduction and pressure build-up are performed analogously to an anti-lock braking system.

[0033] The influence of releasing a brake actuation element during controlled braking, for example, an ABS system on a front wheel (VR), according to the state of the art, is described below using the following examples: Fig. 3 explained. Fig. Figure 3 shows the basic schematic progressions of the driver form p. VD (Line 20), the pressure model value 21 of the wheel determined on the basis of an internal pressure model (wheel brake pressure assumed within the framework of brake pressure control, e.g. calculated from valve switching times etc.) and the actual wheel pressure p R (Line 22) is shown as a function of time t. The ABS control (Line 21) receives no information about the pre-pressure modulation 20 during a pressure build-up modulation. For this reason, the controlled pressure build-up phases of the individual ABS control cycles are identical (A).

[0034] Until the ABS control begins at t0, the driver's pre-pressure value 20, the pressure model 21, and the actual wheel pressure 22 all have the same value. With the first ABS brake pressure reduction at t0, the pressure model value of the wheel pressure 21, which corresponds to the actual wheel pressure 22 in the interval from t0 to t1, is lower than the pre-pressure value 20 (see also the description of ABS control above). The first brake pressure reduction at t0 is followed by brake pressure build-up phases (first control cycle A) until the wheel slips again, and further control cycles A (brake pressure reduction followed by brake pressure build-up phases) occur.

[0035] If, for example, the driver begins to release the brake lever during ABS brake pressure regulation (see line 20), the pre-pressure 20 drops below the actual wheel pressure 22 or the pressure model value 21 at time t1. In an ABS braking system without the possibility of active pressure build-up, the actual wheel brake pressure 22 cannot exceed the applied pre-pressure 20; therefore, from time t1 onward, the actual wheel brake pressure 22 follows the curve of the applied pre-pressure 20. If no data is available to detect pressure modulations by the driver (pre-pressure 20), e.g., because no corresponding sensors are present or the sensors are defective, or if the ABS control system does not evaluate such data, the brake pressure control system has no information about the pre-pressure modulation 20, and the calculated pressure model value 21 increases according to the usual control cycle A.

[0036] At time t2, the pre-pressure 20 is increased again by the driver. However, the actual wheel pressure 22 remains at a lower level, as the wheel pressure 22 can only be increased by the pressure build-up pulses of the ABS control (corresponding to the usual control cycle A). The actual wheel pressure 22 therefore follows the slope of the pressure model 21, but starting from the lower initial level of the pre-pressure 20 at t2. This consequently leads to a loss of braking performance (in Fig. 3 represented by the hatched area) and to a partially hard brake lever, since the ABS control assumes a different pressure level (21) than is actually present (22).

[0037] In systems without sensors to detect brake actuation parameters (such as pressure sensors, lever travel sensors, or similar), or in the event of sensor failure, it is therefore desirable for the driver to be able to indirectly detect and assess pressure modulations. Without or without sufficient detection, the driver experiences a negative impact on lever feel during pre-pressure modulations during ABS control (as described above), potentially leading to underbraking (deceleration) of the vehicle due to discrepancies between the actual wheel brake pressure 22 and the pressure model value 21. Furthermore, braking performance can be impaired during near-complete release, as – in addition to the aforementioned discrepancy in the pressure model – the caliper clearance must be overcome by the pressure build-up sequence of the brake pressure control system.

[0038] Since the feel of the hand lever and the relationship between hand lever actuation and deceleration are particularly important for motorcyclists, as they strongly influence their perceived sense of safety, such detection is of great importance, especially for systems that lack direct release detection mechanisms (e.g., appropriate sensors such as a pressure sensor that determines the pre-pressure). This also applies to braking systems that include sensors for detecting brake lever actuation, but where these sensors are unavailable, for example, due to a malfunction, or where, due to a suspected fault, the evaluation / consideration of sensor data for safety-critical functions is not to be carried out.

[0039] In Fig. Figure 4 shows a first embodiment of a method according to the invention schematically in the form of a flowchart. If, during controlled braking (block 30), a release of a brake actuation element by the driver is detected based on a vehicle dynamic parameter X (block 31), the brake control is modified (block 32).

[0040] The brake control in block 30 can be, for example, an anti-lock braking system (ABS control) and / or a control to prevent, reduce or eliminate rear wheel lift (RLP control).

[0041] The method according to the invention is preferably used to detect a release of the front wheel brake actuation element (e.g.

[0042] Handbrake lever 3 in Fig. 1) is used because the feel of the hand lever is more important for the rider's perceived safety than the feel of the foot lever. Furthermore, the front brake is typically used more frequently. The front brake also contributes more to the overall braking performance, so a loss of brake pressure (reduced braking effect) at the front wheel (FR) due to releasing the brake lever is more critical for safety.

[0043] The following section first describes in more detail some exemplary release detection procedures which are carried out individually or in combination to detect when a driver releases a brake actuation element (e.g. in Block 31), and then describes various exemplary modified brake control procedures (Block 32) when a release is detected, which improve the control behavior of the system and / or reduce the loss of braking power to a minimum.

[0044] According to a second embodiment of the method according to the invention, the state of a (relevant) release of the brake lever by the driver is detected by evaluating the vehicle deceleration a. This assumes that a decrease in vehicle deceleration a can only be achieved by a reduction in the (actual) wheel pressure p. R If this occurs during a pressure build-up phase (no activation of the release valve), this state can only be created by the pressure reduction in the wheel brake via the check valve usually located in the inlet valve (or, depending on the perspective, the check valve usually connected in parallel to the inlet valve). For example, the vehicle deceleration a is monitored and a release is detected when the current vehicle deceleration a aktuell by more than a predetermined or calculated difference value Δa (positive, Δa>0) from a previously reached maximum amount a max differs by smaller amounts: |aaktuell|<|amax|−Δa

[0045] The vehicle deceleration *a* is derived, for example, from the wheel speed signals. Alternatively, the vehicle deceleration can be calculated by time differentiation (e.g., numerical differentiation) from the vehicle reference velocity *v*. REF The ABS function is determined. However, the vehicle deceleration a can also be measured using sensors, e.g., a longitudinal acceleration sensor, or obtained from the data of a position detection system or satellite system (GPS), or determined from the measurement data of a speed-over-ground sensor.

[0046] In Fig. 5 are exemplary time profiles of a vehicle speed of 50 (e.g., the reference speed v). REF ), a wheel speed of 51 (v R ), a vehicle delay 52 (a), a form 53 (p VD ) and a wheel pressure of 54 (p R ) shown. At time t 11Due to the driver releasing the brake lever, the pre-pressure 53 falls below the wheel brake pressure 54.

[0047] Based on Fig. Section 5 below describes an example of release detection based on the vehicle deceleration a. During one (advantageously every) pressure build-up phase, the vehicle deceleration is observed and the maximum vehicle deceleration a is recorded. max learned. The learned maximum vehicle deceleration a max will be adjusted to the current vehicle delay a aktuell (Line 52) compared. At time t 12 is the current vehicle deceleration a aktuell (Line 52) outside the permitted deviation Δa and it is concluded that the driver reduced the pressure (released the valve).

[0048] A new learning phase for maximum vehicle deceleration a max is started, for example, by a pressure release. The current vehicle deceleration a aktuellThe vehicle is constantly monitored, and the largest amount of deceleration is recorded and then used as a comparison value. max used until the regulation brings about a new pressure reduction and a new learning phase begins.

[0049] The maximum permissible deviation Δa can be fixed or derived from the learned maximum vehicle deceleration a. max can be calculated, e.g. as a percentage of a max .

[0050] It is also possible that a release is only recognized when the current vehicle deceleration a aktuell for a given time period ΔT1 lies outside the allowed deviation Δa.

[0051] According to a third embodiment of the method according to the invention, the state of a (relevant) release of the brake lever by the driver is determined by an evaluation of the wheel speed v R, in particular an evaluation of wheel speed changes or wheel deceleration a R Detected. Based on the assumption that wheel speeds decrease steadily during braking, an unexpected increase or insufficient change indicates that the driver has released the brakes. Wheel speed and / or wheel speed change information is therefore used for release detection or as a component of release detection.

[0052] In Fig. Figure 6 shows exemplary curves for a vehicle speed of 60 (e.g., the reference speed v). REF ), a wheel speed of 62 (v R ), of a form 63 (p VD ) and a wheel pressure of 64 (p R ) shown. Based on Fig. Section 6 below describes an example of a solution detection method based on the change in wheel speed v. R described.

[0053] At time t 22The ABS control system enters a pressure reduction phase because the wheel speed 62 deviates from the reference speed 60 by more than a predefined threshold 65 (a slip start occurs). The data is stored in a memory containing the last wheel speed values ​​v R If the wheels are stored for a predetermined period of time, the wheel speed v will be determined. R at a time t 21 read out. This value v R (t 21 ) is used as the starting value for an extrapolation of 66 of the maximum wheel speed v R max used. For this purpose, a predetermined (specifically for the vehicle) or certain minimum deceleration during braking is used as the slope (or gradient) of the extrapolation 66. If the (current) wheel speed 62 exceeds the extrapolated value v R max for a fixed time period ΔT2, in Fig. 6, indicated by arrow I, suggests, for example, a reduction in pre-pressure by the driver.

[0054] For comparison, in Fig. 6 for times t from time t 23 , at which the wheel speed v R The minimal value is represented by the curve of the wheel speed 61 for the case in which no pressure reduction would take place. The wheel speed 61 does not exceed the extrapolated value 66 (indicated by arrow II), which is why, correctly, no pressure reduction would be detected by the exemplary procedure.

[0055] For example, the time t 21 , which serves as the time point for the starting value v R (t 21 ) the extrapolation 66 is used to calculate a given time interval Δt before time t 22 of pressure reduction. However, it is also conceivable that the time interval Δt is chosen depending on other information (adaptive adjustment).

[0056] According to a fourth embodiment of the method according to the invention, instead of the wheel speed v R at time t 21 the reference velocity v REF at time t 21 The maximum wheel speed is used as a starting value for extrapolating 66. It is also conceivable that the larger of the two speeds (wheel speed and reference speed) could be used as the starting value.

[0057] Since both the evaluation of the vehicle deceleration change (second embodiment) and the evaluation of the wheel speed gradients (third embodiment) can be faulty under certain circumstances, the reliability of the detections is preferably improved (avoidance of false detections) by using further information for threshold setting and / or for the significance of the detection.

[0058] To meaningfully define one or more threshold and / or target values, e.g., the difference value Δa, the time duration ΔT2, and / or the minimum deceleration used for extrapolation, it is important to capture the braking torque reduction by the system itself. For this reason, the amount of the reduced pressure Δp is measured. abbau (magnitude of brake pressure reduction during the pressure reduction phase) and, on the other hand, the time ΔT3 until the wheel regains acceleration (e.g., time interval between points in time t). 23 and t 22 in Fig. 6) recorded and used as a scaling factor for the threshold and / or target values. Thus, the detection becomes less sensitive the longer a pressure drop lasts (the longer pressure is maintained after a pressure drop) and / or the greater the pressure drop. By evaluating this additional information, a reliable distinction can be made between a change in the coefficient of friction and a reduction in pre-pressure.

[0059] For example, a solution detection is not performed if the product of Δp abbau and ΔT3 is greater than a given threshold.

[0060] For example, the minimum delay and / or the time duration ΔT2 used for extrapolation is chosen depending on the product of Δp and ΔT3.

[0061] According to a fifth embodiment of the method according to the invention, the state of a (relevant) release of the brake lever by the driver (pre-pressure reduction) is determined by an evaluation of the wheel acceleration a R with regard to their vibration behavior, in particular the signal damping caused by the wheel brake pressure. In Fig. 7 are schematically exemplary curves of wheel speed 70 (v R ) of the front wheel, the associated wheel acceleration 71 (a R ) as well as the course 72 of the form p VDThe curves of the wheel pressure 73 (p) are also shown for illustration. R ) (at the front wheel) and the wheel speed of the rear wheel (74) are shown. One can Fig. 7 a vibration behavior of the wheel acceleration a R the front wheel with a damping of the amplitude. The signals from time t 70 correspond to a smaller pre-print p VD , the signals from time t 71 correspond to a larger pre-print p VD (see course 72).

[0062] By analyzing the wheel acceleration signals of a wheel, the wheel brake pressure p can be qualitatively determined by examining its oscillation behavior. Rclosed. For example, the vibration behavior can be fitted with a parameterized function suitable for describing a damped vibration, and the damping constant can be determined from the specified parameters. High damping of the vibration indicates a high preload (see graph 72 in Fig. 7 from time t 71 ), so that "no release" is detected. Low damping of the vibration suggests low pre-pressure (see curve 72 in Fig. 7 from time t 70 ), so that a solution is detected.

[0063] For example, the damping coefficient of the wheel's rotational acceleration is determined using a mathematical description of the wheel's rotational acceleration profile over a specific period, in order to deduce the current wheel pressure. A simplified equation of motion for the wheel can be considered for this purpose, yielding the following relationship (torque balance): J⋅φ¨=μ⋅FN⋅r−p⋅A⋅k where J moment of inertia of the wheel under consideration, φ̈ wheel acceleration, µ coefficient of friction, F N Normal force acting on the wheel, r radius of the wheel, p wheel pressure, A Sum of the areas which are subjected to p (e.g. sum of the piston areas), k sum constant (is determined empirically, for example, or from the effective braking radius and the coefficient of friction between brake pad and brake disc).

[0064] As can be seen, the wheel acceleration ̈̈̈φ̈ is directly related to the pressure p. A change in wheel acceleration thus indicates (at least qualitatively) a change in pressure. Therefore, if a description of the wheel acceleration is established, a qualitative statement about the pressure can be made from it.

[0065] The following describes which modifications to the regulation ( Fig. 4, Block 32) for example, if during controlled braking ( Fig. 4, Block 30) a release of a brake actuation element by the driver was detected ( Fig. 4, Block 31).

[0066] Fig. Figure 8 shows the effect of releasing a brake actuation element during controlled braking when carrying out a sixth embodiment of the method according to the invention. Similar to a Fig. Figure 3 schematically depicts the principal curves of the driver's pre-pressure 80, the internal pressure model 81 (assumed wheel brake pressure within the framework of brake pressure control), and the actual wheel pressure 82 as a function of time t. At time t 40 An ABS regulation begins. At time t 41 Due to the driver releasing the brake lever, the pre-pressure 80 falls below the wheel brake pressure 81, 82. At time t 42A release of the brake actuation element, e.g., according to the first or second embodiment, is detected. At time t 43 The driver increases the pressure to 80 again.

[0067] To minimize the impact on the still active ABS control after the (detected) reduction in pre-pressure, the following occurs after detection at time t 42 The pressure build-up gradient B of the brake pressure control is significantly increased compared to the pressure build-up gradient of the previous control cycles A (for example, to 200 bar / s to 400 bar / s). However, an immediate termination of the ABS control is not advisable, as the actual pressure conditions cannot be clearly determined and this can lead to a very unstable driving condition.

[0068] If the driver increases his speed at time t 43When the pre-pressure is restored, the steeper build-up gradient B ensures that the desired braking power is provided quite quickly, without negatively impacting the driver for an unnecessarily long time. This allows for a safe transition until the next ABS pressure reduction. The resulting braking power loss is 85 (in Fig. 8 (represented by the hatched area) is significantly lower than in the case without solution detection and change of the rule strategy (see hatched area in Fig. 3).

[0069] The controlled pressure build-up gradient B after the detected pre-pressure reduction should not, however, last longer than the maximum time of a normal ABS pressure build-up phase. After this, complete pressure equalization between wheel pressure and pre-pressure is assumed.

[0070] Instead of or in addition to the above-described increase of the pressure build-up gradient B within the current control cycle (before the next ABS pressure reduction), the ABS control can also be modified after release is detected such that the entry conditions (e.g., the slip thresholds) for a new control cycle (the next brake pressure reduction) are changed. Preferably, the slip thresholds are increased upon release.

[0071] It is also possible that instead of increasing the pressure build-up gradient B within the current control cycle (before the next ABS pressure reduction) as described above, the pressure build-up gradient is first increased for the next control cycle.

Claims

[1] Method for detecting when a brake actuation element (3, 5) of a motorcycle is released by the rider, wherein the motorcycle comprises an electronically controlled braking system with at least one brake pressure control function, wherein during a brake pressure control (30) carried out by the brake pressure control function successive values ​​of at least one vehicle dynamic parameter (X, a, v) R, a R ) determined, and at least partially stored, and - by comparing a current value (a aktuell , v R ) the parameter with a comparison value (a max , v R max ), and / or - from the time course of the values ​​of the parameter (a R ) It is detected (31) whether the driver has released a brake actuation element (3, 5), whereby the vehicle dynamics parameter is a vehicle deceleration (a) or a wheel rotation speed (v). R ) or a wheel rotation acceleration (aR ) is, characterized by , that the driver releases the brake actuation element (3, 5) - based on a decrease in the amount of vehicle deceleration (a), and / or - based on the magnitude of a decrease in wheel rotational speed (v) R ), and / or - from a vibration behavior of the wheel rotational acceleration (a R ) is recognized wherein the braking system does not have a sensor to detect an actuation by the driver of a brake actuation element (3, 5) assigned to a brake circuit (1, 2). [2] Method according to claim 1, characterized by , that during a pressure build-up phase of the brake pressure control, a maximum vehicle deceleration (a max ) is learned and the current vehicle deceleration (a aktuell ) with the maximum vehicle deceleration (a max ) is compared. [3] Method according to claim 2, characterized by, that a release of a brake actuation element (3, 5) by the driver is deemed to be recognized when the magnitude of the current vehicle deceleration (a aktuell ) is less than the maximum vehicle deceleration (a) by more than a predetermined or specific vehicle deceleration deviation amount (Δa). max ). [4] Method according to claim 3, characterized by , that a release of a brake actuation element (3, 5) by the driver is deemed to be recognized when the magnitude of the current vehicle deceleration (a aktuell ) for a given time period (ΔT1) is smaller than the maximum vehicle deceleration amount (a) by more than a given or specific vehicle deceleration deviation amount (Δa). max ) . [5] Method according to claim 3 or 4, characterized by , that the vehicle deceleration deviation amount (Δa) depends on the learned maximum vehicle deceleration (a) max ) is determined. [6] Method according to claim 1, characterized by , that upon entering a brake pressure reduction phase of the brake pressure control at a first time point (t 22 ) a starting velocity value at a second time point (t 21 ) is determined, where the second time point (t 21 ) before the first time point (t 22 ) is that a speed comparison value is determined from the initial speed value and that the current wheel rotation speed (62) is compared with the speed comparison value (66). [7] Method according to claim 6, characterized by , that the initial speed value is a wheel rotation speed (62, v R ) or a vehicle speed (60) at the second time (t 21 ) is. [8] Method according to claim 6 or 7, characterized by , that the speed comparison value (v R max) starting from the initial velocity value by extrapolation (66) with a predetermined or specified minimum deceleration. [9] Method according to any one of claims 6 to 8, characterized by , that a release of a brake actuation element (3, 5) by the driver is deemed to be recognized when the current wheel rotation speed (62, v R ) becomes greater than the velocity comparison value (v) for a given time period (ΔT2). R max ). [10] Method according to any one of claims 6 to 9, characterized by , that the second time point (t 21 ) by a fixed time period (Δt) or a time period calculated from current driving state variables before the first time (t 22 ) lies. [11] Method according to claim 1, characterized by , that to detect a release of a brake actuation element, an analysis of the vibration behavior of the wheel acceleration (a R ) is carried out. [12] Method according to any one of claims 1 to 11, characterized by , that the detection of a release of a brake actuation element (3, 5) is carried out taking into account the currently determined brake torque reduction. [13] Method according to any one of claims 1 to 12, characterized by , that if the brake actuation element (3, 5) is detected to be released, the brake pressure control carried out by the brake pressure control function is modified. [14] Method according to claim 13, characterized by , that a pressure control strategy and / or at least a control threshold of the brake pressure control and / or at least a control and / or comparison variable of the brake pressure control is modified. [15] Method according to claim 13 or 14, characterized by , that a pressure build-up gradient of the brake pressure control is changed. [16] Method according to one of the claims Claims 13 to 15, characterized by, that an entry threshold for a brake pressure control cycle is changed. [17] Method according to any one of claims 1 to 16, characterized by , that this is carried out to detect the release of a brake actuation element (3) for actuating a front wheel brake circuit (1) of the motorcycle. [18] Electronically controlled braking system of a motorcycle with at least one brake pressure control function, wherein the braking system provides values ​​of at least one vehicle dynamic parameter (X, a, v) R, a R ) detected or values ​​of at least one vehicle dynamics parameter are supplied to the braking system, wherein the braking system comprises a means for detecting a release of a brake actuation element (3, 5) by the driver, which detects a release of the brake actuation element (3, 5) based on the values ​​of the vehicle dynamics parameter (a, v) R, a R) recognizes where the vehicle dynamics parameter is a vehicle deceleration (a) or a wheel rotation speed (v) R ) or a wheel rotation acceleration (a R ) is, characterized by , that the driver releases the brake actuation element (3, 5) - based on a decrease in the amount of vehicle deceleration (a), and / or - based on the magnitude of a decrease in wheel rotational speed (v) R ), and / or - from a vibration behavior of the wheel rotational acceleration (a R ) - is detected, whereby the braking system does not have a sensor to detect an actuation of a brake actuation element (3, 5) assigned to a brake circuit (1, 2) by the driver. [19] Electronically controlled braking system according to claim 18, characterized by , that the braking system includes a control unit which, upon detection of a release of a brake actuation element (3, 5), performs a modified brake pressure control. [20] Electronically controlled braking system of a motorcycle according to one of claims 18 or 19, characterized by a control unit in which a method according to one of claims 1 to 17 is carried out.

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