DE102012215790A1 - Control device for pump motor of pump used in hydraulic brake system of vehicle, has control unit to define the predefined value of predetermined minimum rotational speed variable relative to target minimum rotational speed of motor - Google Patents

Abstract

The control device (10) has a motor control unit (16) that defines a target rotational speed variable related to a target rotational speed of pump motor (12) and outputs the target rotational speed variable related to motor control signal (18) to motor. The control unit defines the predefined value of predetermined minimum rotational speed variable relative to target minimum rotational speed of motor, corresponding to the volume variable (V) measured with respect to the operation of motor and/or RMS current size measured with respect to time interval of RMS current of motor. An independent claim is included for a method for operating pump motor.

Description

The invention relates to a control device for a pump motor of at least one pump of a brake system. Likewise, the invention relates to a pump motor for at least one pump, a pump for a brake system and a hydraulic brake system. Furthermore, the invention relates to a method for operating a pump motor of at least one pump of a brake system.

State of the art

In the DE 10 2010 062 816 A1 is described an ABS regulation. If a blockage of at least one assigned wheel is determined by means of at least one wheel speed sensor, the intake valve associated with the respective wheel is closed to execute the ABS control. In addition, the exhaust valve cooperating with the respective intake valve is opened, so that a hydraulic fluid located in the adjacent wheel brake can flow into a storage chamber. The hydraulic fluid is fed back from there by means of a return pump in the direction of the master cylinder.

Disclosure of the invention

The invention relates to a control device for a pump motor of at least one pump of a brake system with the features of claim 1, a pump motor for at least one pump of a brake system with the features of claim 5, a pump for a brake system with the features of claim 6, a hydraulic brake system with the features of claim 7 and a method for operating a pump motor of at least one pump of a brake system with the features of claim 8.

Advantages of the invention

The invention realizes a pump motor drive, which causes an improved NVH behavior (noise-vibration harshness) by means of an achievable speed reduction of a pump of a brake system. By reducing the running during the controlled operation of the pump motor speed noise pollution of vehicle occupants is prevented. In addition, the reduction causes the driver of the vehicle equipped with the brake system to feel (almost) no vibration during operation of a brake operating member / brake pedal. The present invention thus enables a better ride comfort for both the driver and for any vehicle occupants.

As will be explained in more detail below, the present invention also provides improved protection of the pump motor thereby extending its life / service life. Thus, by means of the present invention, costs for repairing / replacing the pump motor / pump equipped therewith can be saved.

Advantageously, the engine control unit is designed to set a target minimum speed, a target minimum pump power to be provided by the pump motor, a target minimum voltage to be provided on the pump motor, or a setpoint minimum current to be provided to the pump motor as the target minimum speed variable. This facilitates the definition of a suitable setpoint speed variable, for example as a setpoint speed, as desired pumping power, as a target voltage to be provided to the pump motor or as a setpoint current to be supplied to the pump motor.

In an advantageous embodiment, the engine control device is additionally designed to set the target minimum speed variable with additional consideration of a provided counter-pressure variable with respect to a master brake cylinder internal pressure. The controlled operation of the pump motor can thus be optimized with regard to a counterpressure counteracting the transfer of brake fluid from a wheel brake cylinder / storage chamber in the direction of the master brake cylinder.

In a further advantageous embodiment, the engine control device is designed to take into account an estimated storage level of a storage chamber as the estimated volume size with respect to the liquid volume to be discharged by the operation of the pump motor. Alternatively, however, the engine controller may also be configured to account for another estimated or measured volume size for determining the desired minimum speed magnitude.

The advantages described above can also be realized by means of a pump motor for at least one pump of a brake system, a pump for a brake system and a hydraulic brake system, which comprise the advantageous control device.

Furthermore, the advantages described above can be achieved by carrying out a corresponding method for operating a pump motor of at least one pump of a brake system.

Brief description of the drawings

Further features and advantages of the present invention will be explained below with reference to the figures. Show it:

1 a schematic representation of an embodiment of the control device and a cooperating brake system; and

2 a coordinate system for explaining an embodiment of the method for operating a pump motor of a pump of a brake system.

Embodiments of the invention

1 shows a schematic representation of an embodiment of the control device and a cooperating brake system.

In the 1 schematically illustrated control device 10 is designed to be a pump motor 12 at least one pump 14 to control the sketched braking system. It should be noted that the usability of the control device 10 not on a particular type of pump motor 12 and the driven by at least one pump 14 is limited. Instead, the control device 10 for a variety of different types of pump motors 12 and pumps 14 designed / optimized.

The control device 10 may be mounted as a separate unit on a vehicle equipped with the braking system. The control device 10 However, it can also be integrated in another control electronics of the vehicle, for example in a central vehicle control electronics or in a brake control electronics. Likewise, the control device 10 a subunit of the pump motor 12 and / or the at least one pump 14 be. By integrating the control device 10 In at least one further vehicle component space can be saved on the vehicle.

The control device 10 includes a motor control device 16 , by means of which a desired speed variable with respect to a target speed of the pump motor 12 is determinable. A motor control signal corresponding to the specified target speed quantity 18 is to the pump motor 12 dispensable. The setting of the desired rotational speed variable takes place taking into account at least one default variable, wherein at least one desired minimum rotational speed variable can be taken into account as the at least one predefined variable. The engine control device 16 is additionally configured to set the target minimum speed magnitude taking into account a measured or estimated volume size with respect to an operation of the pump motor 12 liquid volume to be dissipated and / or a measured or estimated effective current quantity with respect to one during a predetermined time interval by the pump motor 12 set effective RMS.

The use of the engine control device 16 ensures reliable protection of the pump motor 12 against overheating during a suspension of a wheel lock with a simultaneous advantageous NVH behavior of the at least one pump operated 14 , In particular, by the onset of the engine control device 16 one of the target minimum speed size corresponding actual minimum speed of the pump motor 12 be lowered so that an oversized engine load of the pump motor 12 is further avoided and / or a better NVH behavior of at least one pump 14 is reached. The engine control device 16 in particular, that of the pump motor 12 executed actual minimum speed / actual speed to actually present load conditions, which may be both vehicle and situation specific adapt.

The target minimum speed quantity is a quantity related to a target minimum speed of the pump motor 12 , It is thus possible to rewrite the setpoint minimum speed variable as a variable which has a setpoint minimum speed of the pump motor 12 defines / define. For example, the engine control device 16 be configured to as the target minimum speed size, a target minimum speed, one of the pump motor 12 Target minimum pump power to be provided, one to the pump motor 12 to be provided minimum required voltage or to the pump motor 12 to set the minimum required amperage to be provided. However, instead of the examples listed here, a different size, which is an operation / a performance of the pump motor 12 characterized / defined, as the target minimum speed variable be defined. For example, also a desired minimum operating level of the pump motor 12 in which the pump motor 12 at least executes a certain minimum speed, be specified as a target minimum speed variable.

Accordingly, as the target speed amount, a target speed, one of the pump motor 12 Target pump power to be provided, a target operating stage of the pump motor 12 , one on the pump motor 12 to be provided Voltage or one to the pump motor 12 be set to be provided target amperage. Also, the target speed is not limited to the here enumerated embodiments.

The engine control signal 18 can in particular one to the pump motor 12 provided actual voltage or one to the pump motor 12 be provided actual amperage. Likewise, the engine control signal 18 a switching signal for switching an electronics of the pump motor 12 or to a power supply unit of the pump motor 12 be provided control signal.

In an advantageous embodiment, the engine control device takes into account 16 in determining the desired minimum speed magnitude, a measured or estimated volume size with respect to that through operation of the pump motor 12 dissipated liquid volume. For example, the engine control device 16 be adapted to an estimated storage level of a storage chamber 20 as the estimated volume size with respect to the volume of liquid to be removed by the operation of the pump motor. By using the accumulator size, which is often already present as the arithmetic variable in the vehicle software, a more advantageous definition of the desired minimum rotational speed variable is possible. Likewise, the engine control device 16 However, also be designed to by means of the operation of the pump motor 12 to be taken into account volume flow V / storage chamber volume flow in determining the target minimum speed size. Also for estimating the volume flow V / storage chamber volume flow often software is already stored on an on-board electronics.

In a further advantageous embodiment, which is possible as a supplement or as an alternative to taking into account the volume size described above, the determination of the target minimum speed variable taking into account a measured or estimated RMS current with respect to during the predetermined time interval by the pump motor 12 be performed effective current. Excessive current supply to the pump motor 12 can cause overheating of the pump motor 12 , and thus lead to its damage. By the described adaptation of the controlled operation of the pump motor 12 on the other hand, its operation can be heated by the pump motor 12 be reliably prevented. For this purpose, for example, during the predetermined time interval by the pump motor 12 guided RMS current can be measured. However, an estimate of a corresponding RMS current magnitude is also readily feasible, as a motor current model for the pump motor 12 in software of the engine control device 16 is easily stored.

If the setting of the target minimum speed variable takes place in consideration of an estimated volume size and / or an estimated effective current quantity, the engine control device can 16 be designed to estimate the respective size or to receive as estimated value. In both cases, an NVH-optimized designability of the control device 10 possible.

It should be noted that the advantageous design of the engine control device described here 16 the controlled operation of the pump motor 12 can be easily optimized in terms of characteristic sizes of the brake system. In particular, the engine control device 16 at an insertion of the pump motor 12 in a brake system with a smaller brake volume, a gentler operation of the pump motor 12 and a lower NVH load due to the operation of the at least one pump 14 guarantee. By means of the engine control device 16 is in particular a reduction of the means of the pump motor 12 running current speed possible when the actual load conditions are below maximum load conditions or a fill curve approach. When using the control device described here 10 also eliminates the conventional need, the pump motor 12 to control with consideration of a filling curve of different vehicle classes.

In an advantageous development, the engine control device 16 additionally configured to set the target minimum speed magnitude with additional consideration of a provided backpressure amount / minimum pressure magnitude with respect to a master cylinder internal pressure. The counter-pressure variable can be, for example, by means of a pressure sensor 22 be measured pressure / back pressure, which in at least one pressure chamber of a master cylinder 24 is present. In this way, the operation of the pump motor 12 be additionally optimized.

In the embodiment of the 1 the brake system has a brake pedal designed as a brake pedal 26 on, which on the master cylinder 24 is connected. Optionally, at least one sensor 28 , such as a rod travel sensor or a brake pressure sensor, on the brake actuator 26 be arranged. In addition, a brake booster 30 and a brake fluid reservoir 32 still with the master cylinder 24 be connected.

In the embodiment of the 1 is the master cylinder 24 designed as a tandem master cylinder, on which two brake circuits 34 are connected. The two brake circuits 34 are the same. However, the control device 10 also be used for a brake system whose brake circuits 34 are formed differently.

In the 1 illustrated brake circuits 34 are each with a high pressure switching valve 36 , a changeover valve 38 , one of the already described pumps 14 , one of the storage chambers 20 , two wheel brake cylinders 40 , one wheel inlet valve each 42 per wheel brake cylinder 40 and one wheel outlet valve each 44 per wheel brake cylinder 40 fitted. The respective pump 14 can supply side with the associated changeover valve 38 and the wheel inlet valves 42 of the same brake circuit 34 be connected. The suction side is the respective pump 14 preferably with the associated high-pressure switching valve 36 , the adjacent storage chamber 20 (Low pressure storage chamber) and the wheel outlet valves 44 of the same brake circuit 34 connected. Optionally, the brake circuits can 34 in addition to the pressure sensor 22 , which, for example, to a supply line of a brake circuit 34 is connected, even more pressure sensors 46 to have. Preferably, a check valve 48 between the pump 14 and the adjacent storage chamber 20 arranged. However, it is pointed out again that the training of the brake circuits 34 of the 1 merely to be interpreted as an example.

Advantageously, the at least two pumps 14 the two brake circuits 34 on a common wave 50 be arranged, which by means of the pump motor 12 is operable. As a development, however, the brake system can also be several pump motors 12 have, each with the same control device 10 are controllable.

2 shows a coordinate system for explaining an embodiment of the method for operating a pump motor of at least one pump of a brake system.

The method described below can be carried out, for example, by means of the control device described above. The feasibility of the method is not limited to the onset of this control device.

For carrying out the method, a setpoint speed variable with respect to a setpoint speed of the pump motor is determined taking into account at least one default variable. Subsequently, the pump motor is controlled taking into account the set target speed variable so that the pump motor rotates at an actual speed corresponding to the target speed variable.

However, before setting the target speed amount, a target minimum speed amount with respect to a target minimum speed of the pump motor is set as the at least one preset amount. The setting of the target minimum speed variable takes place taking into account a measured or estimated volume size with respect to a liquid volume to be discharged by operation of the pump motor and / or a measured or estimated effective flow quantity with respect to an effective current conducted by the pump motor during a predetermined time interval. Examples of measuring and estimating the volume size or the RMS flow size are already outlined above. For example, For example, an estimated storage level of a storage chamber may be taken into account as the estimated volume size with respect to the volume of liquid to be removed by the operation of the pump motor.

In the method described here, the setting of the target minimum speed variable takes place with additional consideration of a provided counter-pressure variable with respect to a master brake cylinder internal pressure. In the coordinate system of 2 the abscissa indicates a counterpressure p / master brake cylinder internal pressure [in bar] as counterpressure magnitude. The ordinate of the coordinate system of 2 indicates a target minimum speed setpoint minimum speed Dmin [in rpm (revolutions / minute)]. (Instead of the target minimum speed Dmin, however, it is also possible, for example, to specify a desired minimum pump power to be provided by the pump motor, a setpoint minimum voltage to be provided to the pump motor, or a setpoint minimum current to be provided to the pump motor as the target minimum speed variable.)

A graph 52 corresponds to a curve of the target minimum speed Dmin at a storage chamber level of 1.5 cm ³ / s. For comparison, by means of another graph 54 a curve of the target minimum speed Dmin at a storage chamber level of 1.2 cm ² / s specified. As by comparing the two graphs 52 and 54 recognizable, the effect compared to the graph 52 reduced storage chamber level of the graph 54 a difference Δ of 400 [rpm]. While the target minimum speed Dmin thus increases with an increasing backpressure p, a lower storage chamber level, or a lower volume flow to be transferred, can nevertheless be used to reduce the target minimum speed Dmin. In this way, an improved NVH behavior of a pump operated by means of the pump motor and reliable protection of the pump motor are ensured.

The method described here can be carried out by means of a simple storage of a suitable hardware on a control electronics. It ensures improved protection of at least one pump motor operated therewith prior to a thermal load. Instead of a speed specification as filling curve (worst case) of different vehicle types / vehicle classes, this is taken into account here described method a current situation of the pump motor and / or specific sizes / parameters of cooperating with the pump motor brake system. In this way, more favorable conditions for reducing the target minimum speed can be used.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010062816 A1 [0002]

Claims (11)

Control device ( 10 ) for a pump motor ( 12 ) at least one pump ( 14 ) of a brake system comprising: a motor control device ( 16 ), by means of which a desired speed variable with respect to a target speed of the pump motor ( 12 ) is determinable taking into account at least one default variable (Dmin) and a motor control signal corresponding to the target rotational speed variable ( 18 ) to the pump motor ( 12 ) is dispensable; characterized in that the engine control device ( 16 ) is additionally designed, as the at least one default variable (Dmin), a target minimum rotational speed variable (Dmin) with respect to a target minimum rotational speed (Dmin) of the pump motor ( 12 ) taking into account a measured or estimated volume size (V) with respect to a volume of liquid (V) to be discharged by operation of the pump motor and / or a measured or estimated effective flow quantity with respect to a pump motor during a predetermined time interval ( 12 ) established effective current. Control device ( 10 ) according to claim 1, wherein the engine control device ( 16 ) is configured as the target minimum speed variable (Dmin) a target minimum speed (Dmin), one of the pump motor ( 12 ) to be provided target minimum pump power, one to the pump motor ( 12 ) to be provided minimum voltage or to the pump motor ( 12 ) to be provided setpoint minimum amperage. Control device ( 10 ) according to claim 1 or 2, wherein the engine control device ( 16 ) is additionally designed to set the target minimum speed variable (Dmin) with additional consideration of a provided counter-pressure variable (p) with respect to a master brake cylinder internal pressure (p). Control device ( 10 ) according to one of the preceding claims, wherein the engine control device ( 16 ) is designed to estimate an estimated storage level of a storage chamber ( 20 ) as the estimated volume size (V) with respect to the liquid volume (V) to be discharged by the operation of the pump motor. Pump motor ( 12 ) for at least one pump of a brake system with a control device ( 10 ) according to any one of the preceding claims. Pump ( 14 ) for a braking system with a control device ( 10 ) according to one of claims 1 to 4 and / or a pump motor ( 12 ) according to claim 5. Braking system with a control device ( 10 ) according to one of claims 1 to 4, a pump motor ( 12 ) according to claim 5 and / or a pump ( 14 ) according to claim 6. Method for operating a pump motor ( 12 ) at least one pump ( 14 ) of a brake system comprising the steps of: setting a target speed quantity with respect to a target speed of the pump motor ( 12 ) taking into account at least one default quantity (Dmin); and driving the pump motor ( 12 ) taking into account the set target speed so that the pump motor ( 12 ) rotates with an actual speed corresponding to the target speed variable; characterized by the step of: setting a target minimum speed quantity (Dmin) with respect to a target minimum speed (Dmin) of the pump motor ( 12 ) as the at least one default quantity (Dmin) taking into account a measured or estimated volume size (V) with respect to a by an operation of the pump motor ( 12 ) liquid volume (V) to be discharged and / or a measured or estimated effective current quantity with respect to one during a predetermined time interval by the pump motor ( 12 ) guided RMS current. The method of claim 8, wherein as the target minimum speed variable (Dmin) a target minimum speed (Dmin), one of the pump motor ( 12 ) to be provided target minimum pump power, one to the pump motor ( 12 ) to be provided minimum voltage or to the pump motor ( 12 ) is to be provided setpoint minimum amperage. The method of claim 8 or 9, wherein the target minimum speed variable (Dmin) is set with additional consideration of a provided counter-pressure variable (p) with respect to a master brake cylinder internal pressure (p). Method according to one of claims 8 to 10, wherein an estimated storage level of a storage chamber ( 20 ) as the estimated volume size (V) with respect to the operation of the pump motor ( 12 ) to be discharged liquid volume (V) is taken into account.

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