EP1509435A1 - Method for operating an actuating unit for motor vehicle brakes - Google Patents
Method for operating an actuating unit for motor vehicle brakesInfo
- Publication number
- EP1509435A1 EP1509435A1 EP03727490A EP03727490A EP1509435A1 EP 1509435 A1 EP1509435 A1 EP 1509435A1 EP 03727490 A EP03727490 A EP 03727490A EP 03727490 A EP03727490 A EP 03727490A EP 1509435 A1 EP1509435 A1 EP 1509435A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- pressure
- electromagnet
- value
- current
- phase
- 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.)
- Ceased
Links
- 238000000034 method Methods 0.000 title claims abstract description 19
- 238000007789 sealing Methods 0.000 claims abstract description 20
- 238000012423 maintenance Methods 0.000 claims description 8
- 230000001105 regulatory effect Effects 0.000 claims description 5
- 238000009423 ventilation Methods 0.000 claims description 4
- 230000015556 catabolic process Effects 0.000 claims description 3
- 230000007704 transition Effects 0.000 claims description 3
- 230000006978 adaptation Effects 0.000 claims description 2
- 230000001276 controlling effect Effects 0.000 claims 1
- 230000009467 reduction Effects 0.000 description 6
- 230000008859 change Effects 0.000 description 5
- 239000012528 membrane Substances 0.000 description 4
- 230000005540 biological transmission Effects 0.000 description 3
- 230000008569 process Effects 0.000 description 2
- 230000004913 activation Effects 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 230000002459 sustained effect Effects 0.000 description 1
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
- 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
- B60T13/66—Electrical control in fluid-pressure brake systems
- B60T13/72—Electrical control in fluid-pressure brake systems in vacuum systems or vacuum booster units
Definitions
- the invention relates to a method for operating an actuation unit for motor vehicle brakes consisting of a master brake cylinder and a pneumatic brake booster with an booster housing, the interior of which is divided by a movable wall into a first chamber (vacuum chamber) and a second chamber (working chamber), and with a control housing , in which a control valve acting on the movable wall acting pneumatic pressure difference is arranged, a first sealing seat which can be actuated by an actuating rod, the opening of which enables ventilation of the working chamber, a second sealing seat, the opening of which enables a connection between the two chambers, and one having elastic valve bodies interacting with the two sealing seats, the first sealing seat or a further sealing seat interacting with the valve body being independent of an actuation initiated by the vehicle driver in the sense of ventilation of the working chamber can be actuated by an electromagnet which can be controlled by means of an electronic control and regulating unit, the activation of which leads to a build-up, a holding and a dismantling
- the input pressure must be corrected after a certain time in order to minimize the difference that has occurred between the predetermined pressure and the input pressure in the master cylinder, which arises, for example, due to a leak in the brake booster. It is considered less advantageous that, in the previously known method, the control current of the electromagnet remains at a level which brings the coil of the electromagnet to the load limit and thus endangers the operational safety of the brake booster.
- this object is achieved in that the electromagnet during a pressure-holding phase which is carried out independently of an actuation initiated by the vehicle driver, even after the pressure introduced in the master cylinder has been adjusted to a predetermined pressure value is driven with a minimal current that does not result in a pressure drop.
- the minimum current value is determined by reducing the current driving the electromagnet during the pressure-holding phase until a predetermined pressure drop occurs and a predetermined value I 0 is added to this reduced current value.
- FIG. 2 shows an embodiment of an externally actuated brake booster in longitudinal section; partially broken away, in the inactive standby position,
- Fig. 4 time courses of the current supplied to the electromagnet and the pressure applied in the master cylinder during a pressure maintenance phase carried out independently of the will of the driver.
- the brake system for motor vehicles partially shown in Fig.l consists essentially of an actuating unit 1, a pressure regulator 12 and wheel brakes of a motor vehicle, not shown.
- the actuation unit 1 in turn consists of a pneumatic brake booster that can be actuated both by means of an actuation pedal 4 and independently of an actuation initiated by the driver, preferably a vacuum brake booster 2, to which a master brake cylinder, preferably a tandem master cylinder 3, is connected, the pressure chambers of which are not shown hydraulic lines 9, 10 are connected to the wheel brakes.
- An actuating rod 5 is coupled to the actuating pedal 4, which actuates the mechanical actuation of a control Valve 6 is used to control the build-up and breakdown of a pneumatic differential pressure in the housing of the vacuum brake booster 2.
- An electromagnet 7 enables (external) control of the control valve 6 independently of the actuation initiated on the actuating rod 5 by the driver of the vehicle.
- the electromagnet 7 is controlled by a control signal of the pressure regulator 12 by means of a current control element contained in the pressure regulator 12.
- a pressure sensor 13 connected to one of the pressure chambers of the tandem master cylinder 3 determines the hydraulic pressure applied in the tandem master cylinder 3.
- the comparison circuit 11 is a pressure setting signal P supplied so ⁇ that obtained with the introduced into the master brake cylinder 3 and referred to by the pressure sensor 13 before hydraulic pressure is compared Pist to form a control deviation Dp.
- the comparison result .DELTA.p is fed as an input variable to the pressure regulator 12, which in turn controls the electromagnet 7 with the help of the current actuator, as just explained.
- Fig. 2 shows an embodiment of an externally actuated vacuum brake booster that can be used for the purpose of the pressure control mentioned.
- the merely schematically indicated booster housing 20 of this brake booster is divided by an axially movable wall 22 into a working chamber 23 and a vacuum chamber 24.
- the axially movable wall 2 consists of a membrane plate 28 deep-drawn from sheet metal and an adjoining flexible membrane 29, which, not shown in detail, forms a rolling membrane as a seal between the outer circumference of the membrane plate 28 and the amplifier housing 20.
- a control valve 6, which can be actuated by the actuating rod 5, is accommodated in a control housing 25, which is sealed in the booster housing 20 and supports the movable wall 22, and consists of a first sealing seat 15 formed on the valve piston 26 connected to the actuating rod 5, and a second sealing seat 16 formed in the control housing 25 , a third sealing seat 30 arranged radially between the two sealing seats 28, 29 and an annular valve body 31 which cooperates with the sealing seats 15, 16, 30 and is guided in a guide part 32 arranged in a sealed manner in the control housing 25 and which is supported by means of a valve spring 33 which is supported on the guide part 32 is biased to the sealing seats 15, 16, 30.
- the working chamber 3 can be connected to the vacuum chamber 4 via a channel 41 running laterally in the control housing 25.
- the braking force is transmitted to an actuating piston of a master brake cylinder, not shown, of the brake system, which is attached to the vacuum-side booster housing half, via a rubber-elastic reaction disk 36, which rests on the end face of a front part 17 which is supported on the control housing 25, and a pressure rod 18 having a head flange 21.
- an approximately radially extending channel 27 is finally formed in the control housing 25.
- the return movement of the valve piston 26 at the end of a braking process is limited by a cross member 34, the release position of the vacuum brake booster shown in the drawing on a in the booster housing se 1 trained stop 19 is present.
- the electromagnet 7 mentioned in connection with FIG. 1 is provided, which is preferably arranged in a housing 35 firmly connected to the valve piston 26 and accordingly together with the valve piston 26 is displaceable in the control housing 25.
- the electromagnet 7 consists of a coil 36 arranged inside the housing 35 and an axially displaceably arranged cylindrical armature 37, which is partly guided in a closure part 38 closing the housing 35 and on which a force transmission sleeve 39 is supported, which supports the third sealing seat 30 mentioned above wearing.
- a compression spring 40 is arranged, which holds the armature 37 in its starting position, in which the third sealing seat 30 is arranged axially offset with respect to the first sealing seat 15 formed on the valve piston 26.
- the closing part 38 which is guided in the control housing 25, bears against the previously mentioned reaction disk 36 with the interposition of a transmission disk 42 and enables the input force introduced on the actuating rod 5 to be transmitted to the reaction disk 36.
- the electromagnet 7 is actuated with a comparatively high current during a pressure maintenance phase and in particular also after an adjustment of the pressure applied in the master brake cylinder 3 to the predetermined pressure value during the pressure maintenance phase.
- This comparatively high current places an unnecessarily high load on the coil of the electromagnet 7.
- a current that lies in value between points D and N does not result in a change in pressure. If the pressure applied in the master brake cylinder 3 is to be increased, the electromagnet 7 must be controlled with a current which is greater than the current value I N from point N, the so-called pressure build-up point. To reduce the pressure in the master brake cylinder, the electromagnet 7 must accordingly be controlled with a current which is smaller than the current value I D from point D, the so-called pressure reduction point.
- the electromagnet 7 is actuated with a comparatively high current during a pressure-maintaining phase and in particular after an adaptation of the pressure introduced in the master brake cylinder 3 to the predetermined pressure value, which corresponds to the value-related proximity to the pressure build-up point N in FIG. 3 .
- the pressure-maintaining phase is also implemented when the current assumes a value that is somewhat greater than the current value I D from the pressure reduction point D, but is significantly lower than the current value I N from the pressure build-up point N in FIG. 3.
- the solenoid 7 will be the new process during a pressure holding phase, and also after a take place during the pressure holding phase adjustment introduced into the master cylinder 3 pressure according st p ⁇ at the predetermined pressure value Ps o ii it a small current value I m i n activated, the currently no initiated pressure drop.
- This current value I m i n is slightly greater than the current value I D of the pressure reduction point D in Fig. 3.
- the current value I N of the pressure build-up point N and the pressure reduction point D, however, I D, and thus the current value I m i n take for each Brake booster individual values, because they vary, for example, both with the age of the brake booster and depending on the ambient conditions (strength of the engine vacuum, temperature).
- FIG. 4 a total of three time profiles are shown, which are identified by the Roman numerals I to III.
- the time course I shows the pressure value p so ⁇ , for example predetermined by a sensor provided outside the control system, while the time course II represents the pressure p ⁇ s t introduced in the master brake cylinder 3.
- the current required to reach the pressure curve mentioned, which drives the electromagnet 7, is shown in the time curve III.
- Section A shows a pressure build-up phase. If the specified pressure value remains constant for a certain time (section B), then at time ti, the current driving the electromagnet 7 is slowly reduced until a predetermined reduction in the pressure applied in the master cylinder 3 compared to the pressure value at time ti of for example, 2 bar occurs. A predetermined value I 0 is added to the current value I ab reached at time t 2 . With the current value Imi n determined in this way, the electromagnet 7 is driven during the sustained pressure maintenance phase (section D).
- a pressure p so ⁇ internally specified by the electronic control and regulating unit is used internally so that the adjustment of the pressure pi St entered in the master brake cylinder 3 to the predetermined pressure p so is not carried out too quickly, or so that there is no overshoot of the pressure Pist entered in the master brake cylinder 3.
- the input pressure Pi S t can briefly become substantially greater than the predetermined pressure p so ⁇ , which is registered as uncomfortable “jerking” by the occupants of the motor vehicle.
- the internally predetermined pressure p so ⁇ , i n ter n takes At the beginning of the pressure build-up phase, that is to say at time t 3 in FIG. 3, the value of pi st and gradually approaches the predetermined pressure value p so ⁇ - However, the gradient of the change is limited tiert, so that the internally predetermined pressure Psoii, internally only after some time, at the time t _, the value of p S oi ⁇ . Otherwise, the pressure regulator 12 (see FIG. 1) works again as before the start of the method according to the invention (see section A) until the pressure setpoint (p S oi ⁇ ) remains constant over a certain period of time.
Landscapes
- Engineering & Computer Science (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Braking Systems And Boosters (AREA)
- Regulating Braking Force (AREA)
Abstract
Description
Claims
Applications Claiming Priority (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE10222722 | 2002-05-23 | ||
DE10222722 | 2002-05-23 | ||
DE10302085 | 2003-01-21 | ||
DE10302085A DE10302085A1 (en) | 2002-05-23 | 2003-01-21 | Method for operating an actuation unit for motor vehicle brakes |
PCT/EP2003/005242 WO2003099627A1 (en) | 2002-05-23 | 2003-05-19 | Method for operating an actuating unit for motor vehicle brakes |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1509435A1 true EP1509435A1 (en) | 2005-03-02 |
Family
ID=29585301
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP03727490A Ceased EP1509435A1 (en) | 2002-05-23 | 2003-05-19 | Method for operating an actuating unit for motor vehicle brakes |
Country Status (3)
Country | Link |
---|---|
US (1) | US8128179B2 (en) |
EP (1) | EP1509435A1 (en) |
WO (1) | WO2003099627A1 (en) |
Family Cites Families (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE4208496C1 (en) * | 1992-03-17 | 1993-08-05 | Mercedes-Benz Aktiengesellschaft, 7000 Stuttgart, De | |
DE4324688A1 (en) | 1993-07-23 | 1995-01-26 | Teves Gmbh Alfred | Vacuum brake servo unit |
DE4415651C1 (en) * | 1994-05-04 | 1995-04-27 | Daimler Benz Ag | Brake-pressure control device |
DE19508822A1 (en) * | 1995-03-11 | 1996-09-12 | Teves Gmbh Alfred | Brake system for motor vehicles |
DE19527493A1 (en) * | 1995-07-27 | 1997-01-30 | Lucas Ind Plc | Electromagnetic actuator |
DE19541101A1 (en) * | 1995-11-06 | 1997-05-07 | Teves Gmbh Alfred | Method for operating a pneumatic brake booster |
DE19541535A1 (en) | 1995-11-08 | 1997-05-15 | Teves Gmbh Alfred | Method for operating a pneumatic brake booster |
DE19542654A1 (en) * | 1995-11-15 | 1997-05-22 | Lucas Ind Plc | Electronic controllable braking system for motor vehicles |
DE19609192A1 (en) | 1996-03-09 | 1997-09-11 | Teves Gmbh Alfred | Method for operating a pneumatic brake booster |
ES2130749T3 (en) * | 1996-04-03 | 1999-07-01 | Lucas Ind Plc | ELECTRONICALLY REGULATED POWER BRAKE. |
DE19624376A1 (en) * | 1996-06-19 | 1998-01-02 | Teves Gmbh Alfred | Brake system for motor vehicles |
DE19720099A1 (en) * | 1997-05-14 | 1998-11-19 | Itt Mfg Enterprises Inc | Vacuum assisted brake servo for motor vehicle |
DE19744052C1 (en) * | 1997-10-06 | 1998-10-22 | Lucas Ind Plc | Electronically controlled valve for vehicle braking force booster |
DE19750383C1 (en) * | 1997-11-13 | 1998-12-24 | Lucas Ind Plc | Pneumatic brake booster for motor vehicle |
US6318815B1 (en) * | 1998-01-31 | 2001-11-20 | Continental Teves Ag & Co., Ohg | Braking force boosting device, in particular for automotive vehicles |
DE19940252A1 (en) * | 1998-10-27 | 2000-06-15 | Continental Teves Ag & Co Ohg | Device and method for controlling the braking force of a brake system |
FR2825058B1 (en) * | 2001-05-25 | 2003-09-19 | Bosch Sist De Frenado Sl | FIXED AND VARIABLE TWO-DIFFERENTIAL JUMP SERVO MOTOR |
-
2003
- 2003-05-19 EP EP03727490A patent/EP1509435A1/en not_active Ceased
- 2003-05-19 WO PCT/EP2003/005242 patent/WO2003099627A1/en active Application Filing
- 2003-05-19 US US10/515,620 patent/US8128179B2/en not_active Expired - Fee Related
Non-Patent Citations (1)
Title |
---|
See references of WO03099627A1 * |
Also Published As
Publication number | Publication date |
---|---|
US20060108862A1 (en) | 2006-05-25 |
WO2003099627A1 (en) | 2003-12-04 |
US8128179B2 (en) | 2012-03-06 |
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Legal Events
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17Q | First examination report despatched |
Effective date: 20101018 |
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18R | Application refused |
Effective date: 20111126 |