How to perform functional tests in hydraulic non-human-powered vehicle braking systems

Abstract

To perform a functional test in the pressure generating module (2) of a hydraulic non-human-powered vehicle braking system (1), the present invention proposes generating brake pressure by a non-human-powered brake pressure generator (4) and then hydraulically isolating the pressure regulating module (3) from the pressure generating module (2) by closing the connecting valve (21) or the hydraulic wheel brakes (22) by closing the inlet valve (23), thereby preventing brake fluid from flowing into the wheel brakes (22) during the functional test, which would reduce the brake pressure in the pressure generating module (2) and potentially adversely affect or prevent the functional test.

Description

[Technical field]

[0001] The invention relates to a method for carrying out a function test in a pressure generating module of a hydraulic, in particular non-human-powered vehicle braking system with slip control, which comprises a pressure generating module for the non-human generation of braking pressure and a pressure regulating module connected to said pressure generating module for regulating the braking pressure and / or for slip control. [Background technology]

[0002] Patent document 1 discloses a hydraulic non-human-powered vehicle brake system with slip control, which comprises an electrohydraulic non-human-powered brake pressure generator arranged in a pressure generating module and a pressure regulating module with slip control, which has a solenoid valve and a return pump, and which is connected to the pressure generating module. For muscle operation, this known vehicle brake system has a main brake cylinder, which is integrated in the pressure generating module.

[0003] Patent document 2 discloses a method for testing the functionality of a slip-controlled hydraulic non-powered vehicle brake system. In this case, brake fluid is pumped separately in each brake circuit by a non-powered brake pressure generator through a non-operated main brake cylinder into a pressureless brake fluid reservoir. The brake circuits are connected to the main brake cylinder through a cut valve, which is not necessarily visible during service braking performed as non-powered braking, and the non-open cut valve is checked by the method for testing the functionality of the vehicle brake system by pressure build-up. One disadvantage of this known method is that brake fluid can flow from the non-powered brake pressure generator through the open inlet valve into the hydraulic wheel brakes of the vehicle brake system, which delays the pressure build-up and adversely affects the test. To prevent this outflow volume flow, the inlet valve of the hydraulic wheel brake in the respective brake circuit may be closed during the test. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] DE 102016201047 [Patent Document 2] DE 102018212850 Summary of the Invention

[0005] The method according to the invention with the features of claim 1 preferably comprises carrying out a function test in a pressure generating module of a hydraulic non-powered vehicle braking system with slip control, the function test being used to check the functionality of the pressure generating module or of hydraulic components of the pressure generating module, such as solenoid valves or check valves.

[0006] The pressure generating module in particular comprises an electrohydraulic brake pressure generator without human power. The brake pressure generator comprises, for example, a piston-cylinder unit, the piston of which is movable in its cylinder by an electric motor via a screw drive or other rotation / translation drive in order to generate the brake pressure without human power. Another possibility for the brake pressure generator is a hydraulic pump, for example a piston pump or an (internal) gear pump, which can be driven by an electric motor.

[0007] The pressure regulation module is connected to the pressure generation module through a connecting valve, which may be integrated in the pressure generation module or in the pressure regulation module. The pressure regulation module is used for regulating the brake pressure, preferably for slip control, and has valves, in particular solenoid valves, for example inlet and outlet valves for hydraulic wheel brakes, which are connected to the pressure regulation module, and possibly further hydraulic components, for example hydraulic accumulators and / or hydraulic pumps. The connecting valves are usually present in non-powered vehicle braking systems which comprise a pressure generation module and a pressure regulation module, therefore the method according to the invention usually does not require additional valves or other modifications of the respective non-powered vehicle braking system.

[0008] The slip control is in particular anti-lock control, anti-slip regulation and / or vehicle dynamics control, the abbreviations of which are commonly used, ABS, ASR and / or FDR, etc. Such slip controls are well known and will not be described herein.

[0009] To carry out the function test, the brake pressure is generated by the non-human brake pressure generator and / or the brake fluid is pumped or pushed away by the non-human brake pressure generator. In order to prevent brake fluid from escaping from the pressure generation module into the pressure regulating module or into the hydraulic wheel brakes during the function test, which would affect the pressure course during the function test and thus have a negative effect on the function test, according to the invention, the brake pressure is generated in the pressure regulating module, preferably also in the wheel brakes, by the non-human brake pressure generator or by the hydraulic pump of the pressure regulating module, and then selectively the connecting valves connecting the pressure regulating module to the pressure generation module and / or the inlet valves of the wheel brakes are closed. The pressure regulating module or in any case the wheel brakes are thereby hydraulically isolated from the pressure generation module and the brake pressure is confined in the pressure regulating module or in any case the wheel brakes. The function test is then carried out in the pressure generation module. In this case, the generation of braking pressure by the non-human brake pressure generator and the confinement of the braking pressure in the pressure regulating module or in the wheel brake may be understood as a component part of a functional test or as a method step for preparing a functional test.

[0010] It is possible to measure the hydraulic brake pressure in the vehicle brake system during the function test. In particular, the relationship between the amount of brake fluid pumped by the non-powered brake pressure generator and the pressure profile is determined. The relationship between the amount of brake fluid and the pressure profile is different when the vehicle brake system is functioning properly and when the valves, for example, do not switch as set. Effect of the Invention

[0011] The invention avoids the pressure regulation module or hydraulic wheel brakes from affecting the functional tests in the pressure generating module.

[0012] A functional test checks the functionality of hydraulic components, for example, of a pressure generating module.

[0013] The dependent claims are directed to developments and advantageous configurations of the invention defined in the independent claims.

[0014] All features disclosed in the specification and drawings may be used alone or in principle in any combination to form an embodiment of the invention. It is also possible in principle to construct the invention having not all the features of one claim or one embodiment of the invention, but only one or more of them.

[0015] The present invention will now be described in detail with reference to the drawings. [Brief description of the drawings]

[0016] [Figure 1] 1 is a hydraulic circuit diagram of a non-human-powered vehicle brake system for implementing the method according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The hydraulic non-human powered vehicle brake system 1 shown in the drawings is a two-system vehicle brake system with slip control. The vehicle brake system 1 includes a pressure generating module 2 and a pressure regulating module 3, and the pressure regulating module 3 is connected to the pressure generating module 2. A hydraulic wheel brake 22 is connected to the pressure regulating module 3.

[0018] The pressure generating module 2 comprises a non-human-powered brake pressure generator 4 having a piston-cylinder unit 5, a piston 6 of which is slidable in a cylinder 9 of the piston-cylinder unit 5 of the non-human-powered brake pressure generator 4 by an electric motor 7 via a screw transmission mechanism 8 so as to non-human-power generate brake pressure. The piston-cylinder unit 5, or the entire non-human-powered brake pressure generator 4, may also be referred to as a plunger unit, the piston 6 of the plunger unit as a plunger piston, and the cylinder 9 of the plunger unit as a plunger cylinder.

[0019] For auxiliary braking in case of failure of the non-human brake pressure generator 4, the pressure generating module 2 has a dual main brake cylinder 10 which can be operated by a foot brake pedal 11 or, alternatively, by muscle power via a hand brake lever (not shown).

[0020] During service braking, when the brake pressure is generated by the non-human brake pressure generator 4, the main brake cylinder 10 is used as a setpoint for the brake pressure to be generated by the non-human brake pressure generator 4. For this purpose, a pressure sensor 12 is connected to the main brake cylinder 10.

[0021] During service braking, the primary brake cylinder 10 is hydraulically isolated from the rest of the vehicle braking system 1 by closure of the cut valve 18. A pedal stroke simulator 13 is connected to the primary brake cylinder 10 via a simulator valve 14 so that during service braking brake fluid can nevertheless be displaced from the primary brake cylinder 10 and thereby move the primary brake cylinder piston and the foot brake pedal 11. The pedal stroke simulator 13 is a piston-cylinder unit having a spring-loaded piston such that when the cut valve 18 is closed and the simulator valve 14 is open brake fluid can be displaced from the primary brake cylinder 10 into the cylinder of this piston-cylinder unit.

[0022] The main brake cylinder 10 and the pedal stroke simulator 13 are integrated within the pressure generation module 2 as is the non-powered brake pressure generator 4 .

[0023] A non-pressurized brake fluid storage container 15 is mounted on the pressure generating module 2, to which the main brake cylinder 10 and the cylinder 9 of the non-human brake pressure generator 4 are connected, the latter through a non-human valve 16.

[0024] The pressure generating module 2 has cut valves 17, 18 in each brake circuit for the non-powered brake pressure generator 4 and the main brake cylinder 10, and through the cut valves 17, 18 the pressure regulating module 3 is connected to the pressure generating module 2, or the brake circuit of the pressure regulating module 3 is connected to the brake circuit of the pressure generating module 2.

[0025] Furthermore, a check valve 19 is integrated in the pressure generating module 3, which connects the brake fluid storage container 15 to the side of the cut valves 17, 18 opposite the non-powered brake pressure generator 4 and the main brake cylinder 10 and allows flow from the brake fluid storage container 15 towards the cut valves 17, 18 and thus to the pressure regulating module 3.

[0026] The pressure generating module 2 has a pressure sensor 20 , which is connected to the cylinder 9 of the non-powered brake pressure generator 4 .

[0027] The pressure regulating module 3 is connected to the pressure generating module 2 through a connecting valve 21 in each brake circuit.

[0028] The hydraulic wheel brakes 22 are each connected to the pressure regulating module 3 via an inlet valve 23. In the present embodiment, the vehicle braking system 1 comprises four wheel brakes 22, of which two wheel brakes 22 are connected to one brake circuit.

[0029] In each brake circuit, the wheel brakes 22 are connected through one outlet valve 24 for each wheel brake 22 to the suction side of a hydraulic pump 25, which may also be called a return pump. The vehicle brake system 1 comprises one hydraulic pump 25 in each brake circuit, which hydraulic pumps 25 can be driven together by one electric motor 26. The discharge side of the hydraulic pump 25 is connected between the connecting valve 21 and the inlet valve 23.

[0030] The suction side of the hydraulic pump 25 is connected hydraulically in parallel to the connecting valve 21 to the pressure generating module 2 through one suction valve 27 in each brake circuit, so that the hydraulic pump 25 of the pressure regulating module 3 can suck brake fluid from the brake fluid storage container 15 through the check valve 19 provided in the pressure generating module 2 and the suction valve 27 provided in the pressure regulating module 3 for rapid brake pressure build-up.

[0031] The connecting valve 21 , the inlet valve 23 , the outlet valve 24 and the suction valve as well as the hydraulic pump 25 are integrated in the pressure regulating module 3 .

[0032] The hydraulic pump 25, the inlet valve 23 and the outlet valve 24 form a brake pressure regulator valve arrangement by which wheel individual slip control, such as anti-lock control, anti-slip regulation and vehicle dynamics control, can be performed, commonly abbreviated as ABS, ASR and FDR. Such slip controls are well known and will not be described here.

[0033] The simulator valve 14, the non-powered valve 16, the cut valves 17, 18, the connection valve 21, the inlet valve 23, the outlet valve 24 and the suction valve 27 are 2-port 2-position directional control solenoid valves, and the cut valve 18, the connection valve 21 and the inlet valve 23 of the main brake cylinder 10 are open in their non-energized basic positions, and the simulator valve 14, the non-powered valve 16, the outlet valve 24 and the suction valve 27 are closed in their non-energized basic positions.

[0034] In order to carry out a function test of the pressure generating module 2 or of the hydraulic components of the pressure generating module 2, according to the invention, a brake pressure is generated by the non-human brake pressure generator 4. At this time, the cut valve 17, the connection valve 21 and the inlet valve 24 of the non-human brake pressure generator 4 are open or are opened, so that the brake pressure generated by the non-human brake pressure generator 4 is applied to the pressure regulating module 3 and to the wheel brakes 22. The cut valve 18 of the main brake cylinder 10 is closed so that the brake fluid is not displaced from the cylinder 9 of the non-human brake pressure generator 4 into the main brake cylinder 10 and through the main brake cylinder 10 into the brake fluid reservoir 15. The outlet valve 24 remains closed so that the brake fluid does not escape from the wheel brakes 22.

[0035] The connecting valve 21 is then closed, so that the pressure regulating module 3 is hydraulically disconnected from the pressure generating module 2 or the wheel brake 22 is hydraulically disconnected from the pressure regulating module 3 and the braking pressure is, as it were, "trapped" in the pressure regulating module 3 or in the wheel brake 22. If no check valve is hydraulically connected in parallel to the inlet valve 23, the inlet valve 23 may also be closed instead of the connecting valve 21.

[0036] Now, the function test of the pressure generating module 2 can be carried out without brake fluid flowing out of the pressure generating module 2 into the pressure regulating module 3 or in any case into the wheel brakes 22, which would affect the pressure measurement in the pressure generating module 2 during the function test and could disturb or even prevent the function test. What can be measured, for example, is the pressure boost by the non-human brake pressure generator 4, whether the brake pressure is maintained, i.e. whether the cut valves 17, 18 and the check valve 19 are tight, and whether the brake pressure decreases if the cut valves 17, 18 are opened, i.e. whether the cut valves 17, 18 open as set.

[0037] When the closed connecting valve 21 or the closed inlet valve 23 is not tight, the brake pressure trapped in the pressure regulating module 3 and / or in the wheel brake 22 prevents brake fluid from flowing out of the pressure generating module 2 into the pressure regulating module 3 or into the wheel brake 22.

[0038] During the function test, the vehicle equipped with the vehicle braking system 1 should preferably be stationary, since the vehicle braking system 1 is under pressure during the function test and therefore normal operation of the wheel brakes 22 is not possible or operation of the vehicle braking system 1 would abort the function test. [Explanation of symbols]

[0039] 1. Non-human powered vehicle brake device 2 Pressure Generation Module 3 Pressure Regulating Module 4. Non-powered brake pressure generator 5 Piston-cylinder unit 6 Piston 7 Electric Motor 8 Screw transmission mechanism 9 Cylinders 10 Main brake cylinder 11 Foot brake pedal 12 Pressure Sensor 13 Pedal Stroke Simulator 14 Simulator valve 15 Brake fluid reservoir 16 Non-human valve 17 Cut valve 18 Cut valve 19 Check valve 20 Pressure Sensor 21 Connection valve 22 Wheel brake 23 Inlet valve 24 Outlet valve 25 Hydraulic Pump 26 Electric Motor 27 Suction valve

Claims

1. 1. A method for performing a functional test in a hydraulic non-human-powered vehicle braking system, comprising: The non-human-powered vehicle brake device includes: a pressure generating module (2) having a non-powered brake pressure generator (4); a pressure regulation module (3) connected to the pressure generating module (2) by a connecting valve (21) and to which hydraulic wheel brakes (22) are connected through an inlet valve (23); having In the method, To carry out the functional test, a brake pressure is generated by the non-human brake pressure generator (4) and the brake pressure is applied to the wheel brakes (22); The connecting valve (21) is then closed and the function test is carried out.

13. A method for performing a functional test in a hydraulic non-human-powered vehicle braking system, comprising:

2. 2. The method according to claim 1, characterized in that the non-human-powered brake pressure generator (4) is connected to a brake fluid reservoir (15) through a non-human-powered valve (16) and / or through a check valve (19).

3. 3. The method according to claim 1, further comprising measuring and evaluating the brake pressure or the brake pressure curve in the pressure generating module (2) after the closing of the connecting valve (21) and / or after the closing of the inlet valve (23).

4. 4. The method according to claim 1, further comprising the step of stopping a vehicle equipped with said non-human-powered vehicle braking device (1) during said execution of said method.

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