US 12,447,942 B2Granted

Method for testing the functional capability of a hydraulic vehicle braking system

AssigneeRobert Bosch GmbH

InventorsCarsten Thierer, Rolf-Hermann Mergenthaler, Otmar Bussmann, Peter Ziegler, Tim-Philipp Jesse

Life of this patent

Estimating the term…

Abstract

For testing the functional capability of a hydraulic power vehicle braking system, a power brake pressure generator is switched on. The power brake pressure generator displaces brake fluid through the non-actuated master brake cylinder into a brake fluid reservoir, which is why no brake pressure is built up. A brake pressure build-up allows a “hidden defect” to be inferred, which has no impact during normal operation and is therefore not noticed.

Claims25

Dependent claims

A method for testing the functional capability of a hydraulic vehicle braking system, the vehicle braking system including a master brake cylinder and a power brake pressure generator, to which jointly at least one hydraulic wheel brake is connected, and a separating valve that is in a line of a brake and is assigned to the master brake cylinder using which the master brake cylinder is hydraulically disconnectable from the power brake pressure generator and the at least one wheel brake, the method comprising the following steps:

switching the power brake pressure generator on when the master brake cylinder is not actuated;
and
after the switching on, measuring and assessing a pressure in the vehicle braking system and/or a movement of the power brake pressure generator;
wherein the method includes at least one of the following features:
(a) testing whether the separating valve is malfunctioning to be in a closed position by executing an algorithm that is configured to cause performance of the following in a testing period:
(i) performing a control to place the separating valve in an open position during an open-valve-position period;
(ii) during the open-valve-position period, performing the switching of the power brake pressure generator to displace brake fluid onto the line of the brake circuit;
and
(iii) identifying that the separating valve is malfunctioning to be in the closed position based on, while the displacement is occurring, a detection of a rotation of the motor being below a predefined rotation rate or slowing;
(b) testing whether the separating valve is malfunctioning to be in the open position by executing an algorithm that is configured to cause performance of the following in the testing period:
(i) performing a control to place the separating valve in the closed position during a closed-valve-position period;
(ii) during the closed-valve-position period, performing the switching of the power brake pressure generator to displace brake fluid onto the line of the brake circuit;
and
(iii) identifying that the separating valve is malfunctioning to be in the open position based on, while the displacement is occurring, a detection of a lack of a slowing of a rotation of the motor;
(c) testing whether a simulator valve, by which a pedal travel simulator is connected to the master brake cylinder, is malfunctioning by executing an algorithm that is configured to cause performance of the following in the testing period:
(i) performing a control to place the simulator valve in a closed position during a closed-simulator-valve-position period;
(ii) during the closed-simulator-valve-position period, performing the switching of the power brake pressure generator to displace brake fluid onto the line of the brake circuit;
and
(iii) identifying that the simulator valve is malfunctioning based on, while the displacement is occurring, at least one of:
a detection of a delay of a deceleration of at least one of a piston and the motor of the power brake pressure generator;
and
a detection of a pressure build up on the brake circuit occurring with a delay;
(d) testing whether a reservoir valve between a brake fluid reservoir and the brake circuit is malfunctioning by executing an algorithm that is configured to cause performance of the following in the testing period:
(i) performing a control to place the reservoir valve in a closed position during a closed-reservoir-valve-position period;
(ii) during the closed-reservoir-valve-position period, performing the switching of the power brake pressure generator to displace brake fluid onto the line of the brake circuit;
and
(iii) identifying that the reservoir valve is malfunctioning based on, while the displacement is occurring, a detection of a lack of the deceleration of the at least one of the piston and the motor of the power brake pressure generator;
and
(e) testing a suctioning function of the power brake pressure generator by executing an algorithm that is configured to cause performance of the following in the testing period:
(i) performing the switching of the power brake pressure generator to displace brake fluid onto the line of the brake circuit by shifting the piston in a pressure-generating direction during a fluid displacement period;
(ii) upon conclusion of the fluid displacement period, closing a power valve thereby disconnecting the power brake pressure generator from the line of the brake circuit;
(iii) while the power valve is in a closed state due to the closing of the power valve, performing a control to shift the piston opposite to the pressure-generating direction;
and
(iv) identifying the suctioning function is malfunctioning based on at least one of:
a detection of a decrease of pressure in a cylinder in which the piston is shifted;
a detection of a deceleration of a movement of the piston;
a detection of a deceleration of the motor.

34 more elements

switching the power brake pressure generator on when the master brake cylinder is not actuated;
and
after the switching on, measuring and assessing a pressure in the vehicle braking system and/or a movement of the power brake pressure generator;
wherein:
the method includes at least one of the following features:
(a) testing whether the separating valve is malfunctioning to be in a closed position by executing an algorithm that is configured to cause performance of the following in a testing period:
(i) performing a control to place the separating valve in an open position during an open-valve-position period;
(ii) during the open-valve-position period, performing the switching of the power brake pressure generator to displace brake fluid onto the line of the brake circuit;
and
(iii) identifying that the separating valve is malfunctioning to be in the closed position based on, while the displacement is occurring, a detection of an increase in current consumption by a motor of the power brake pressure generator;
(b) testing whether the separating valve is malfunctioning to be in the open position by executing an algorithm that is configured to cause performance of the following in the testing period:
(i) performing a control to place the separating valve in the closed position during a closed-valve-position period;
(ii) during the closed-valve-position period, performing the switching of the power brake pressure generator to displace brake fluid onto the line of the brake circuit;
and
(iii) identifying that the separating valve is malfunctioning to be in the open position based on, while the displacement is occurring, a detection of a lack of a pressure increase in the brake circuit in which the separating valve is located;
(d) testing whether a reservoir valve between a brake fluid reservoir and the brake circuit is malfunctioning by executing an algorithm that is configured to cause performance of the following in the testing period:
(i) performing a control to place the reservoir valve in a closed position during a closed-reservoir-valve-position period;
(ii) during the closed-reservoir-valve-position period, performing the switching of the power brake pressure generator to displace brake fluid onto the line of the brake circuit;
and
(iii) identifying that the reservoir valve is malfunctioning based on, while the displacement is occurring, a detection of a lack of the pressure build up on the brake circuit, the algorithm being further configured to cause performance of a control to place a simulator valve, by which a pedal travel simulator is connected to the master brake cylinder, in a closed position during the closed-reservoir-valve-position period;
and
the vehicle braking system includes multiple brake circuits which are each connected to the power brake pressure generator via a respective power valve, and the testing is carried out consecutively for each of the multiple brake circuits, one at a time, by opening respective ones of the power valves for the respective switching of the respective testing performed for the respective ones of the brake circuits.

19 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/259,160Filed 25 May 2019
Priority: DE 102018212850.21 Aug 2018
Published: US 2021/0316709 A114 Oct 2021
Granted: 21 Oct 2025
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

B60T 17/22
Safety devices; Monitoring: devices for monitoring or checking brake systems; Signal devices
B60T 17/221
Devices for monitoring or checking brake systems; Signal devices: procedure or apparatus for checking or keeping in a correct functioning…
B60T 7/042
Foot actuated: by electrical means, e.g. using travel or force sensors
B60T 8/4081
Systems in which a driver input signal is used as a control signal for the additional fluid circuit which is normally used for braking: systems…

Family

US 2021/0316709 A1Pre-grant publication · published 14 Oct 2021
US 12,447,942 B2This patent

From the US filing history. Foreign family members aren’t listed.

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Abstract

switching the power brake pressure generator on when the master brake cylinder is not actuated;
and
after the switching on, measuring and assessing a pressure in the vehicle braking system and/or a movement of the power brake pressure generator;
wherein the method includes at least one of the following features:
(a) testing whether the separating valve is malfunctioning to be in a closed position by executing an algorithm that is configured to cause performance of the following in a testing period:
(i) performing a control to place the separating valve in an open position during an open-valve-position period;
(ii) during the open-valve-position period, performing the switching of the power brake pressure generator to displace brake fluid onto the line of the brake circuit;
and
(iii) identifying that the separating valve is malfunctioning to be in the closed position based on, while the displacement is occurring, a detection of a rotation of the motor being below a predefined rotation rate or slowing;
(b) testing whether the separating valve is malfunctioning to be in the open position by executing an algorithm that is configured to cause performance of the following in the testing period:
(i) performing a control to place the separating valve in the closed position during a closed-valve-position period;
(ii) during the closed-valve-position period, performing the switching of the power brake pressure generator to displace brake fluid onto the line of the brake circuit;
and
(iii) identifying that the separating valve is malfunctioning to be in the open position based on, while the displacement is occurring, a detection of a lack of a slowing of a rotation of the motor;
(c) testing whether a simulator valve, by which a pedal travel simulator is connected to the master brake cylinder, is malfunctioning by executing an algorithm that is configured to cause performance of the following in the testing period:
(i) performing a control to place the simulator valve in a closed position during a closed-simulator-valve-position period;
(ii) during the closed-simulator-valve-position period, performing the switching of the power brake pressure generator to displace brake fluid onto the line of the brake circuit;
and
(iii) identifying that the simulator valve is malfunctioning based on, while the displacement is occurring, at least one of:
a detection of a delay of a deceleration of at least one of a piston and the motor of the power brake pressure generator;
and
a detection of a pressure build up on the brake circuit occurring with a delay;
(d) testing whether a reservoir valve between a brake fluid reservoir and the brake circuit is malfunctioning by executing an algorithm that is configured to cause performance of the following in the testing period:
(i) performing a control to place the reservoir valve in a closed position during a closed-reservoir-valve-position period;
(ii) during the closed-reservoir-valve-position period, performing the switching of the power brake pressure generator to displace brake fluid onto the line of the brake circuit;
and
(iii) identifying that the reservoir valve is malfunctioning based on, while the displacement is occurring, a detection of a lack of the deceleration of the at least one of the piston and the motor of the power brake pressure generator;
and
(e) testing a suctioning function of the power brake pressure generator by executing an algorithm that is configured to cause performance of the following in the testing period:
(i) performing the switching of the power brake pressure generator to displace brake fluid onto the line of the brake circuit by shifting the piston in a pressure-generating direction during a fluid displacement period;
(ii) upon conclusion of the fluid displacement period, closing a power valve thereby disconnecting the power brake pressure generator from the line of the brake circuit;
(iii) while the power valve is in a closed state due to the closing of the power valve, performing a control to shift the piston opposite to the pressure-generating direction;
and
(iv) identifying the suctioning function is malfunctioning based on at least one of:
a detection of a decrease of pressure in a cylinder in which the piston is shifted;
a detection of a deceleration of a movement of the piston;
a detection of a deceleration of the motor.

34 more elements

Facts

Application

17/259,160Filed 25 May 2019

Priority

DE 102018212850.21 Aug 2018

Published

US 2021/0316709 A114 Oct 2021

Granted

21 Oct 2025

Term ends

Not estimatedThe source records don’t support an estimate.

Classification13 codes

B60T 17/22
Safety devices; Monitoring: devices for monitoring or checking brake systems; Signal devices
B60T 17/221
Devices for monitoring or checking brake systems; Signal devices: procedure or apparatus for checking or keeping in a correct functioning…
B60T 7/042
Foot actuated: by electrical means, e.g. using travel or force sensors
B60T 8/4081
Systems in which a driver input signal is used as a control signal for the additional fluid circuit which is normally used for braking: systems…