GB2486062A - Brake having valve control to reduce pulsation flow of a piston pump - Google Patents

Brake having valve control to reduce pulsation flow of a piston pump Download PDF

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Publication number
GB2486062A
GB2486062A GB1120463.3A GB201120463A GB2486062A GB 2486062 A GB2486062 A GB 2486062A GB 201120463 A GB201120463 A GB 201120463A GB 2486062 A GB2486062 A GB 2486062A
Authority
GB
United Kingdom
Prior art keywords
brake
piston pump
valve
wheel
piston
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
GB1120463.3A
Other versions
GB201120463D0 (en
Inventor
Georg Blosch
Juergen Haecker
Harald Hermann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from DE201010062188 external-priority patent/DE102010062188A1/en
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Priority to GB1120463.3A priority Critical patent/GB2486062A/en
Publication of GB201120463D0 publication Critical patent/GB201120463D0/en
Publication of GB2486062A publication Critical patent/GB2486062A/en
Withdrawn legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T17/00—Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features
    • B60T17/02—Arrangements of pumps or compressors, or control devices therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/17—Using electrical or electronic regulation means to control braking
    • B60T8/175—Brake regulation specially adapted to prevent excessive wheel spin during vehicle acceleration, e.g. for traction control
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
    • B60T13/12—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid
    • B60T13/16—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid using pumps directly, i.e. without interposition of accumulators or reservoirs
    • B60T13/18—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release the fluid being liquid using pumps directly, i.e. without interposition of accumulators or reservoirs with control of pump output delivery, e.g. by distributor valves
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/17—Using electrical or electronic regulation means to control braking
    • B60T8/1755—Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/17—Using electrical or electronic regulation means to control braking
    • B60T8/176—Brake regulation specially adapted to prevent excessive wheel slip during vehicle deceleration, e.g. ABS
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/40—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system
    • B60T8/4068—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition comprising an additional fluid circuit including fluid pressurising means for modifying the pressure of the braking fluid, e.g. including wheel driven pumps for detecting a speed condition, or pumps which are controlled by means independent of the braking system the additional fluid circuit comprising means for attenuating pressure pulsations
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/34—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition
    • B60T8/48—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration having a fluid pressure regulator responsive to a speed condition connecting the brake actuator to an alternative or additional source of fluid pressure, e.g. traction control systems
    • B60T8/4809—Traction control, stability control, using both the wheel brakes and other automatic braking systems
    • B60T8/4827—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems
    • B60T8/4863—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems closed systems
    • B60T8/4872—Traction control, stability control, using both the wheel brakes and other automatic braking systems in hydraulic brake systems closed systems pump-back systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B11/00—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B11/00—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation
    • F04B11/0091—Equalisation of pulses, e.g. by use of air vessels; Counteracting cavitation using a special shape of fluid pass, e.g. throttles, ducts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/22—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00 by means of valves

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Transportation (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Regulating Braking Force (AREA)

Abstract

The pulsation of a piston pump 9 of a slip-controlled hydraulic vehicle brake system 1 is reduced by partially opening a valve, in particular a brake pressure build-up valve 4 of a wheel brake 3 during a delivery stroke of the piston pump 9, so that the valve 4 throttles the delivery flow of the piston pump 9 during the delivery stroke. The flow to at least one further wheel brake, preferably a rear wheel brake VR HR, is not reduced. The valve may be controlled sinusoidally. A brake pressure reduction valve 5 may be partially opened during a delivery stroke of the piston pump 9. An isolating valve 7 may be partially opened during a delivery stroke of the piston pump 9. The piston pump 9 may be a single piston pump.

Description

Description Title
Method for operating a hydraulic vehicle brake system The invention relates to a method for operating a hydraulic vehicle brake system having the features of the preamble of Claim 1. The method is preferably applied to a slip-controlled vehicle brake system, because such vehicle brake systems have valves which can be used for carrying out the method. Slip control systems are, for example, antilock, traction slip and/or vehicle dynamics control systems, for which the abbreviations ABS, ASR, ESP and/or FDR are customary. Such slip control systems are known per se.
Prior art
Laid-open application DE 195 01 760 Al discloses a slip-controlled hydraulic vehicle brake system with a dual-circuit master brake cylinder, to which hydraulic wheel brakes are connected via two brake circuits. Each brake circuit is connected to the master brake cylinder by an isolating valve, by means of which it can be isolated hydraulically from the master brake cylinder during slip control, in order to avoid reactions on the master brake cylinder. Each wheel brake has a brake pressure build-up valve, by means of which it is connected to the respective brake circuit, and a brake pressure reduction valve, by means of which it is connected to a suction side of a hydraulic pump. The known vehicle brake system has in each brake circuit a hydraulic pump which is driven jointly with the hydraulic pump of the other brake circuit by.an electric motor. Such hydraulic pumps for slip control are often referred to, though not necessarily correctly, as return pumps. A pressure side of the hydraulic pump is connected between the isolating valve and brake pressure build-up valves. The brake pressure build-up valves and the brake pressure reduction valves form wheel brake pressure modulation valve arrangements, by means of which wheel brake pressures in the wheel brakes and thus wheel brake forces can be controlled wheel-specifically for slip control. Such slip control systems are known per se and will not be explained in more detail here. For slip control the hydraulic pump is driven.
The known vehicle brake system has a dual-piston pump, the pistons of which are arranged in a boxer arrangement and are driven in antiphase. In this case, a pump piston is assigned to each brake circuit, the known vehicle brake system thus having, with respect to the individual brake circuit, a single-piston pump as hydraulic pump. By virtue of their design, piston pumps produce a pulsating delivery flow: they deliver during a delivery stroke, the delivery stroke and pressure course usually being sinusoidal, whereas no delivery takes place during a suction stroke. The pulsating is undesirable for-various reasons. One reason is that the pulsation can often be felt as vibration on a brake pedal and can irritate a driver. Another reason is the mechanical loading of the vehicle brake system by the pressure pulsation. Vibrations which can be felt on the steering wheel of a motor vehicle may also occur. The risk of steering-wheel vibrations is particularly high when the wheel brakes of front wheels are connected to different brake circuits. If the piston pumps of the two brake circuits deliver in antiphase, the left and the right front wheel are braked alternately (more heavily), so that the steering wheel moves alternately to the left and to the right and is excited to vibrate.
To reduce the pressure pulsations, it is known to provide multi-piston pumps with, for example, three pump pistons in each brake circuit which have a phase shift of 120° each. Examples of slip-controlled hydraulic vehicle brake systems with three-piston pumps are disclosed in laid-open application DE 102005 055 057 Al and DE 198 25 114 Al.
Laid-open applications DE 10 2004 061 813 Al and DE 10 2005 037 537 Al adopt another approach to reduce pressure pulsations. The piston pumps of their vehicle brake systems have for each pump piston a compensating piston which has approximately half the piston area of the pump piston and is connected to the pressure side of the pump piston and driven in antiphase to the pump piston. During a delivery stroke of the pump piston, a cylinder of the compensating piston receives part of the delivered volume of the pump piston, for example half, so that the delivery flow is correspondingly reduced. During the suction stroke, during which the pump piston does not deliver any brake fluid, the compensating piston displaces the brake fluid volume previously received, so that the pump piston has a more uniform delivery flow with reduced pulsation, i.e. without the compensating piston.
Both solutions require more than one piston per brake circuit and are consequently of corresponding mechanical complexity.
Disclosure of the invention
The idea on which the invention is based is to reduce pulsations which are produced in particular by a single-piston pump of a slip-controlled hydraulic vehicle brake system by controlling one or more valves. Preferably, one or more existing valves of the vehicle brake system are used to carry out the method according to the invention, so that in the most favourable case no design or structural measures are necessary. In particular, the method according to the invention is provided for a vehicle brake system with single-piston pumps, in which the pulsation is the greatest. By single-piston pump is meant one pump piston per brake circuit. Thus, it may be for example a dual-piston pump, both pump pistons of which are assigned to one brake circuit each. The application of the method according to the invention to vehicle brake systems with multi-piston pumps is not excluded. In general, the method according to the invention is applicable to vehicle brake systems with hydraulic pumps having a pulsating delivery flow. The application of the method according to the invention is intended for manual or power-assisted brake systems which usually have a manually actuable master brake cylinder which may have a vacuum, electromechanical or other brake booster. The method according to the invention is also applicable to power-brake systems or generally to vehicle brake systems which produce a brake pressure with a piston pump.
According to the invention, during operation of the piston pumps of a hydraulic vehicle brake system, thus in particular during slip control, a valve of the vehicle brake system is controlled such that a pulsation of a delivery flow of the piston pump is reduced.
"Control" in the sense of the invention is intended to include both open-loop and closed-loop control. For example, a valve on a pressure side of the piston pump is partially opened during a delivery stroke of the piston pump, so that it throttles the delivery flow of the piston pump. By "partially opened" is meant a partially opened position of the valve, so that the valve throttles the delivery flow of the piston pump or throttles it greater than in the fully opened state. The partially opened position of the valve can also be understood as a partially closed position. It does not matter whether the valve is completely open or closed before or after the delivery stroke. As a result of the throttling, a pressure build-up is slowed down and prolonged, and a maximum pressure downstream of the valve is reduced. According to one configuration of the invention, a brake pressure build-up valve of a wheel brake preferably of a front wheel is controlled in the sense of a throttle of the delivery flow of the piston pump. The delivery flow to the wheel brake of a rear wheel is not throttled in configurations of the invention, because pressure pulsations are less troublesome there. ln one configuration of the invention, a partial opening of the isolating valve during the delivery stroke of the piston pump is also possible, so that the delivery flow flows partially back in the direction of the master brake cylinder. This also reduces the pressure pulsations, but has the disadvantage of a slower and/or lower pressure build-up. In configurations of the invention, it is also possible for a brake pressure reduction valve to be partially opened during the delivery stroke of the piston pump. The invention is suitable especially for vehicle brake systems in which at least one wheel brake of a front wheel and at least one wheel brake of a rear wheel are connected to a brake circuit, because by partial opening of the brake pressure build-up valve of the wheel brake of the front wheel the pressure pulsation in the wheel brake of the front wheel can be reduced where it is more troublesome than in the wheel brake of a rear wheel. The wheel brake of the rear wheel and/or the remaining parts of the brake circuit take up and damp the pressure pulsations.
One configuration of the invention provides for a sinusoidal or similarly curved control curve for the valve which is controlled to reduce the pressure pulsation, because a curved valve control is less sensitive to a phase shift in relation to the stroke of the piston pump than, for example, rectangular, trapezoidal or triangular control curves.
Brief description of the drawing
S
The invention is explained in more detail below with reference to the drawing. The single figure shows a connection diagram of a hydraulic, slip-controlled vehicle brake system for the purpose of explaining the method according to the invention.
S Embodiment of the invention The slip-controlled, hydraulic vehicle brake system 1 illustrated in the drawing has two brake circuits I, II which are connected to a dual-circuit master brake cylinder 2. In the exemplary embodiment, two wheel brakes 3 are connected to each brake circuit I, II, although neither the number of two brake circuits I, II nor the number of two wheel brakes 3 per brake circuit I, II is essential to the invention.
A brake pressure build-up valve 4 and a brake pressure reduction valve 5 are assigned to each wheel brake 3. The brake pressure build-up valves 4 are open 2/2-way solenoid proportional valves in their de-energised normal position, and the brake pressure reduction valves 5 are closed 2/2-way solenoid valves in their de-energised normal position. Connected hydraulically in parallel with the brake pressure build-up valves 4 are check valves 6, through which fluid can flow in the direction from the wheel brakes 3 to the master brake cylinder 2.
Each brake circuit I, II has an isolating valve 7, by which it is connected to the master brake cylinder 2. The brake pressure build-up valves 4 are connected to the isolating valves 7. The isolating valves 7 are open 2/2-way valves in their de-energised normal position, connected in parallel with which are check valves 8, through which fluid can flow from the master brake cylinder 2 in the direction of the wheel brakes 3.
Each brake circuit I, II has a hydraulic pump 9, to the suction side of which the wheel brakes 3 are connected via the brake pressure reduction valves 5. The suction sides of the hydraulic pumps 9 are furthermore connected to the master brake cylinder 2 via intake valves 10. The intake valves 10 are closed 2/2-way solenoid valves in their de-energised normal position.
Connected on the suction side of the hydraulic pumps 9 are furthermore hydraulic accumulators 11, which serve for temporary storage of brake fluid, which flows out of the wheel brakes 3 during slip control due to the opening of the brake pressure reduction valves 5. Arranged between the hydraulic accumulators 11 and the suction sides of the hydraulic pumps 9 are check valves 12, through which fluid can flow in the direction of the hydraulic pumps 9. The hydraulic pumps 9 are driven by a common electric motor 13.
The brake pressure build-up valves 4 and brake pressure reduction valves 5 form brake pressure modulation valve arrangements, by means of which wheel brake pressures in the wheel brakes 3 can be controlled wheel-specifically for slip control. For slip control the hydraulic pumps 9 are driven, and the isolating valves 7 can be closed for slip control, in order to isolate the master brake cylinder 2 hydraulically from the vehicle brake system 1. To draw in brake fluid, the intake valves 10 can be opened.
Slip control systems, for example as antilock brake, traction slip and/or vehicle dynamics control systems (ABS, ASR, ESP, FDR), are known and will not be explained in more detail here.
The vehicle brake system I has a dual-piston pump as the hydraulic pump 9, each brake circuit I, II having a pump element with a pump piston. In other words, each brake circuit I, II has a single-piston pump 9 with one pump piston.
The vehicle brake system I has an X-brake circuit configuration, i.e. the wheel brakes 3 of a front wheel and of a diagonally opposite rear wheel are connected to a brake circuit I, II. For the exemplary embodiment, it is assumed that the wheel brakes 3 of a left-hand front wheel and of a right-hand rear wheel are connected to the brake circuit I and the wheel brakes 3 of a right-hand front wheel and of a left-hand rear wheel are connected to the brake circuit II. By virtue of the design, the single-piston pumps 9 produce a pulsating delivery flow: they deliver during a delivery stroke, whereas they do not deliver during a suction stroke. In order to reduce the pressure pulsations during slip control, i.e. when the piston pumps 9 are driven, the invention provides for partial opening of the brake pressure build-up valves 4 during the delivery stroke of the piston pump 9 of the respective brake circuit I, II, so that they act as throttles. The partial opening of the brake pressure build-up valves 4 can also be understood as partial closing. During the suction strokes of the piston pumps 9, the brake pressure build-up valves 4 are opened. A pressure build-up in the wheel brakes 3 is slowed down by the throttling of the delivery flow of the piston pump 9, and a maximum pressure is reduced. As a result of elasticities of the vehicle brake system 1, the delivery flow is extended in time into the suction stroke of the piston pump 9. Overall, the pulsation of the delivery flow is reduced.
One configuration of the method according to the' invention provides that during slip control only the brake pressure build-up valves 4 of the wheel brakes 3 of the front wheels are partially opened and the brake pressure build-up valves 4 of the wheel brakes 3 of the rear wheels remain open. Thus, only the delivery flow to the wheel brakes of the front wheels 3 is throttled during the delivery stroke of the piston pumps 9. The wheel brakes 3 of the rear wheels and the assigned parts of the vehicle brake system I are thereby available for receiving brake fluid, thus further reducing the pressure pulsations in the wheel brakes 3 of the front wheels. A reduction of the pulsation in the wheel brakes 3 of the front wheels is considered to be more important for reasons of comfort, because the front wheels act on vehicle steering.
A variant of the invention provides for one or both brake pressure reduction valves 5 to be partially opened during the delivery strokes of the piston pump 9 in order to reduce the pulsations of the delivery flow of the single-piston pump 9, thus likewise slowing down the pressure build-up and reducing the maximum pressure. During the delivery stroke of the piston pump 9, brake fluid flows through the brake pressure build-up valve or valves 4 and the brake pressure reduction valve or valves 5 into the hydraulic accumulator 11. In the case where the brake pressure reduction valves 5 are controlled to reduce the pressure pulsation, they are preferably likewise formed as proportional valves. The brake pressure build-up valves 4 can be included in the control or remain fully open on partial opening of the brake pressure reduction valves 5.
The isolating valves 7, which are usually closed during slip control, can, according to the invention, likewise be partially opened during the delivery strokes of the piston pumps 9, so that part of the delivery flow flows to the master brake cylinder 2. This measure too reduces pulsations. It can be employed independently of a control of the brake pressure build-up valves 4 and/or the brake pressure reduction valves 5 or additionally. If the isolating valves 7 are controlled to reduce the pressure pulsation, they are preferably likewise proportional valves.
It should be noted that the partial opening of the valves 4, 5, 7 during the delivery strokes of the piston pumps 9 takes place during slip control, i.e. has to be superimposed on the wheel-specific control of the wheel brake pressure in the wheel brakes 3. The throttling of the delivery flow of the piston pumps 9 during the delivery strokes by the partial opening, according to the invention, of one or more of the valves 4, 5, 7 should not impair the slip control at all or only to small degree.
Preferably, the partial opening or partial closing of the valves 4, 5, 7 occurs sinusoidally or with another curved course, because a valve partial opening or valve closing with a curved course is less sensitive to a phase shift with respect to the delivery strokes of the piston pumps 9.

Claims (11)

  1. Claims 1. Method for operating a hydraulic vehicle brake system (1), which has a piston pump (9), at least one hydraulic wheel brake (3) connected to the piston pump (9), and a valve (4, 5, 7) connected to the piston pump (9) and/or the wheel brake (3), characterised in that during operation of the piston pump (9) the valve (4, 5, 7) is controlled such that a pulsation of a delivery flow of the piston pump (9) is reduced.
  2. 2. Method according to Claim 1, characterised in that during a delivery stroke of the piston pump (9) the valve (4, 5, 7) is partially opened, so that it throttles the delivery flow of the piston pump (9).
  3. 3. Method according to Claim 1, characterised in that at least one further hydraulic wheel brake (3) is connected to the piston pump (9), to which the delivery flow of the piston pump (9) is not reduced.
  4. 4. Method according to Claim 1, characterised in that the valve (4, 5, 7) is controlled sinusoidally.
  5. 5. Method according to Claim 1, characterised in that a brake pressure build-up valve (4) between a pressure side of the piston pump (9) and the at least one hydraulic wheel brake (3) is partially opened during a delivery stroke of the piston pump (9).
  6. 6. Method according to Claim 5, characterised in that a brake pressure build-up valve (4) between the pressure side of the piston pump (9) and at least one further hydraulic wheel brake (3) remains open.
  7. 7. Method according to Claim 6, characterised in that at least one wheel brake (3) of a front wheel is connected via a brake pressure build-up valve (4) to the pressure side of the piston pump (9) and at least one wheel brake (3) of a rear wheel is connected via a brake pressure build-up valve (4) to the pressure side of the piston pump (9), and in that the brake pressure build-up valve of the at least one wheel brake (3) of a front wheel is partially opened and the brake pressure build-up valve (4) of the at least one wheel brake (3) of a rear wheel remains open.
  8. 8. Method according to Claim 1, characterised in that a brake pressure reduction valve (5) between the at least one hydraulic wheel brake (3) and a suction side of the piston pump (9) is partially opened during a delivery stroke of the piston pump (9).
  9. 9. Method according to Claim 1, characterised in that an isolating valve (7) between the pressure side of the piston pump (9) and a master brake cylinder (2) is partially opened during a delivery stroke of the piston pump (9).
  10. 10. Method according to Claim 1, characterised in that the piston pump (9) is a single-piston piston pump (9).
  11. Ii. Method for operating a hydraulic vehicle brake system, substantially as hereinbefore described with reference to the accompanying drawing.
GB1120463.3A 2010-11-30 2011-11-25 Brake having valve control to reduce pulsation flow of a piston pump Withdrawn GB2486062A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB1120463.3A GB2486062A (en) 2010-11-30 2011-11-25 Brake having valve control to reduce pulsation flow of a piston pump

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE201010062188 DE102010062188A1 (en) 2010-11-30 2010-11-30 Method for operating hydraulic vehicle brake assembly, involves controlling braking pressure structure valve, braking pressure sinking valve and separation valve such that pulsation of delivered flow of piston pump is reduced
GB1120463.3A GB2486062A (en) 2010-11-30 2011-11-25 Brake having valve control to reduce pulsation flow of a piston pump

Publications (2)

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GB201120463D0 GB201120463D0 (en) 2012-01-11
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20190366999A1 (en) * 2018-05-30 2019-12-05 Robert Bosch Gmbh Method and Device for Controlling a Hydraulic Brake System
US11124168B2 (en) * 2018-05-30 2021-09-21 Robert Bosch Gmbh Method for controlling a hydraulic brake system
US20220266804A1 (en) * 2019-07-11 2022-08-25 Robert Bosch Gmbh Pump Housing of a Hydraulic Assembly Having an Outlet Valve Receiving Means

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EP0597610A1 (en) * 1992-11-09 1994-05-18 Nabco Limited Liquid pressure source unit for liquid-operated booster
US5876102A (en) * 1994-07-20 1999-03-02 Nisshinbo Industries Inc. Method and apparatus for anti-skid control
WO2010038135A1 (en) * 2008-10-01 2010-04-08 Toyota Jidosha Kabushiki Kaisha Brake control apparatus

Patent Citations (3)

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Publication number Priority date Publication date Assignee Title
EP0597610A1 (en) * 1992-11-09 1994-05-18 Nabco Limited Liquid pressure source unit for liquid-operated booster
US5876102A (en) * 1994-07-20 1999-03-02 Nisshinbo Industries Inc. Method and apparatus for anti-skid control
WO2010038135A1 (en) * 2008-10-01 2010-04-08 Toyota Jidosha Kabushiki Kaisha Brake control apparatus

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20190366999A1 (en) * 2018-05-30 2019-12-05 Robert Bosch Gmbh Method and Device for Controlling a Hydraulic Brake System
US10988128B2 (en) * 2018-05-30 2021-04-27 Robert Bosch Gmbh Method and device for controlling a hydraulic brake system
US11124168B2 (en) * 2018-05-30 2021-09-21 Robert Bosch Gmbh Method for controlling a hydraulic brake system
US20220266804A1 (en) * 2019-07-11 2022-08-25 Robert Bosch Gmbh Pump Housing of a Hydraulic Assembly Having an Outlet Valve Receiving Means
US12097837B2 (en) * 2019-07-11 2024-09-24 Robert Bosch Gmbh Pump housing of a hydraulic assembly having an outlet valve receiving means

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