DESC:FIELD OF INVENTION

The present disclosure generally relates to vehicles. In particular, the present disclosure relates to a system for implementing the Hill-Hold/Auto-Hold feature of an Electric Parking Brake (EPB) by detecting the gradient through the travel of the brake pedal.

BACKGROUND OF INVENTION

Hill-Hold/ Auto-Hold is a function that prevents roll-back of a vehicle when starting from a stand-still on a gradient. When the driver brings the car to a halt, the Electric Parking Brake (EPB) in the vehicle is provided information about the gradient. Based on this information, the EPB applies the parking brake to hold the vehicle. When the driver has to drive the vehicle again, the driver lifts his/her foot of the brake pedal and the vehicle does not roll back. Subsequently, the EPB releases the parking brake when the accelerator is pressed.

For smooth implementation of Hill-Hold/Auto-Hold function, gradient detection is required. Without gradient information, the EPB always applies maximum force, which leads to reduced liner/pad life. Further, the release of the parking brake is not smooth.

Currently, gradient information is easily available on Electronic Stability (ESP) enabled vehicles as ESP has a built-in G-sensor. Alternatively, some vehicles are provided with a G-sensor as a stand-alone sensor on the vehicle, exclusively for this function.

An alternate source of acquiring gradient information is the amount of brake force which the driver applies through the brake pedal to bring the vehicle to a halt on the gradient. Based on the brake pedal position (or travel), the EPB can be programmed to apply in a calibrated manner leading to smoother operation and improved liner/pad life.

However, providing the same function without impact on the life of the pad/liner is the challenge. Therefore there is a need to provide an improved system to overcome at least one of the above problems.
OBJECTS OF INVENTION

Main object of the present invention is to overcome at least one of above problems.
Another object of the present invention is to provide a system for implementing the Hill-Hold/Auto-Hold feature of an Electric Parking Brake (EPB) by detecting the gradient through the travel of the brake pedal in the vehicle.
Still another object of the present invention is to provide a system for Electric Parking Brake (EPB) where the system approximate the gradient of the road based on the detection of brake pedal travel.
Yet another object of the present invention is to provide a system for Electric Parking Brake (EPB) with a brake light switch which can sense pedal travel and publish this information on the vehicle communication network.
Another object of the present invention is to provide a system for Electric Parking Brake (EPB) to map the pedal travel information to target brake force which the EPB will then apply to hold the vehicle.

Other objects and advantages will become apparent from a consideration of the following detailed description taken in connection with the accompanying figures. It will of course be understood that the invention is not limited to the details disclosed but includes all such variations and modification as fall within the spirit of the invention and the scope of the appended claims.

BRIEF DESCRIPTION OF THE ACCOMPANYING FIGURES

The present invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:

FIG. 1 illustrates a potentiometer integrated on brake pedal assembly in accordance with some embodiments of the present disclosure;

FIG. 2 illustrates a current brake light switch with two contacts assembly;

FIG. 3 illustrates a brake light switch with three contacts assembly in accordance with some embodiments of the present disclosure;

FIG. 4 illustrates a flow chart depicting method for determining pedal travel using three contact positions in accordance with some embodiments of the present disclosure; and

FIG. 5 and 6 illustrate a representation of brake light switch mounting location in accordance with some embodiments of the present disclosure.

The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the system illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION OF INVENTION
The foregoing has broadly outlined the features and technical advantages of the present invention in order that the detailed description of the present invention that follows may be better understood. Additional features and advantages of the present invention will be described hereinafter which form the subject of the claims of the present invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the present invention as set forth in the appended claims. The novel features which are believed to be characteristic of the present invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention.
Accordingly, the present invention provides a system for approximating gradient based on pedal travel in the vehicle comprising brake pedal mounted on vehicle, a potentiometer integrated with the said brake pedal, at least one sensor is located on said brake pedal and configured to transmit signal to body control module (BCM), the said BCM being coupled with a controller; and an electric park brake (EPB) configured with said BCM to receive information for applying parking brake.
In one embodiment of the present invention, said potentiometer being a multi-contact rotary switch consisting one or more positions.
In one more embodiment of the present invention, said multi-contact rotary switch consisting three contact positions such as contact 1 position or first position, contact 2 position or second position and contact 3 position or third position.
In another embodiment of the present invention, a brake light switch operably mounted with the said brake pedal.
In still another embodiment of the present invention, said brake pedal being provided with torsion spring.
In yet another embodiment of the present invention, a method for approximating gradient based on pedal travel in the vehicle comprises steps of actuating brake causing brake pedal to travel, transmitting information for the brake pedal travel distance to body control module (BCM) using sensor mounted on the brake pedal, publishing the said information on Controller Area Network (CAN) coupled with said body control module (BCM) in vehicle, reading the said information by electric park brake (EPB); and actuating parking brake by EPB based on the said information according to one or more predetermined conditions.
In another embodiment of the present invention, said distance travelled by brake pedal being calculated using a potentiometer being operably mounted with brake pedal providing multi-contact rotary switch facilitating one or more contacting positions.
In still another embodiment of the present invention, said one or more predetermined conditions being level of gradient such as low gradient and high gradient.
In yet another embodiment of the present invention, said multi-contact rotary switch consisting three contact positions where, in contact 3 position or third position, brake being released and brake light being OFF; in contact 2 position or second position, brake being pressed, the brake pedal travels up to a predetermined distance, the brake light glows and the gradient is calculated as low; and in contact 1 position or first position, brake being pressed, the brake pedal travels beyond the predetermined distance and the gradient is calculated as high.
In another embodiment of the present invention, the said contact positions being detected by the potentiometer or multi-contact rotary switch.
In still another embodiment of the present invention, brake light switch operably mounted with said brake pedal.
In yet another embodiment of the present invention, said brake light switch comprises a movable plunger, upon travelling predetermined distances by the said plunger brake light gets activated and gradient information is calculated.
In another embodiment of the present invention, the parking brake application status being indicated by instrument cluster of the vehicle.

The present invention provides a method and system for approximating gradient based on pedal travel detected by the brake light switch (BLS). In an embodiment, the present invention provides an improved BLS for detecting pedal travel.

According to an embodiment of the present invention, gradient is approximated by using brake pedal travel while driver stops vehicle on gradient. Higher the gradient, higher is pedal travel. In an exemplary embodiment of the present invention, by using three contact brake light switch, the pedal travel can be categorized as low (<30mm) and high (>30mm) and the EPB may apply brake force as given in table below:

Table 1
Table 1 shows the approximate pedal travel to halt the vehicle for various road gradients and the corresponding brake force required at the parking brake according to an exemplary embodiment of the present invention. When the pedal travel is up to 30 mm for gradients up to 18%, this corresponds to up to 60 kg of force at the parking brake. Similarly, when the pedal travel is greater than 30 mm for gradients between 18-30%, for 30% gradient, this corresponds to up to 120 kg of parking brake force is required.

By detecting the brake pedal travel, in the manners described here below, the requirement of a G-sensor can be eliminated and still the Auto hold function can be provided effectively to protect the actuator and liner durability.

Referring to fig. 1, a potentiometer integrated on brake pedal assembly in the vehicle is illustrated in accordance with an embodiments of the present invention. In an embodiment, a potentiometer is integrated on the brake pedal assembly to determine the brake pedal travel for applying parking brakes so as to execute Hill hold or Auto hold. The potentiometer / multi-contact rotary switch may be incorporated on the hinge axis of the pedal. The potentiometer can detect continuous brake pedal travel with high resolution. The multi-contact rotary switch can detect pedal travel up to multiple positions. Preferably, the multi-contact rotary may be 3 points contact such as, (a) initial for brake light activation, then (b) for ‘low’ and finally (c) for ‘high’ braking). The sensors are wired to the Body Control Module (BCM) (replacing the connection of the BLS). The BCM will publish the value on Controller Area Network (CAN) which can then be read by Electric Park Brake (EPB) of Electronic Control Unit (ECU). It can use this information to apply the parking brakes as per the target mapped against the pedal position to execute Hill-Hold / Auto-Hold.

Referring to fig. 2, current brake light switch circuit with two contacts assembly in the vehicle is illustrated in accordance with an embodiments of the present invention. The contacts marked as G and H correspond to the plunger in pushed condition (13) and the contact marked as J and K correspond to the plunger in free position (14). The fig. 3 illustrates the circuit with three contacts assembly in accordance with some embodiments of the present invention.

In an embodiment, a position sensor may be incorporated within existing Brake Light Switch (BLS). The BLS has a plunger which makes electrical contact with an internal switch when the brake pedal is pressed (causing the brake light to light up). Two additional contacts can be incorporated along the plunger travel. The switch can now detect pedal travel up to 3 positions i.e. first position, initial for brake light activation, then second position, for ‘low’ and third position, ‘high’ braking. After the initial pedal travel, which may be corresponding to 2-3 mm plunger travel, BLS is activated. For further pedal travel i.e. upto second position, where the plunger travel may be between 3 mm to 7 mm, this may be considered as ‘low gradient’. Even further pedal travel i.e. upto third position, where the plunger travel may be beyond 7 mm, this may be considered as ‘high gradient’. The switch is wired to the BCM. The BCM publishes the position on CAN which can be read by EPB ECU. In an exemplary embodiment, the EPB applies brake force in two discrete levels – around 30% brake force for ‘low’ and 100% brake force for ‘high’. The circuit as illustrated in Fig. 3 is a part BLS. Contact no. 3 (marked as E and F in Fig. 3) corresponds to the pedal released condition (brake pedal not pressed) at which the plunger of the BLS is fully compressed. As the brake pedal is pressed, initially contact no. 2 (marked as C and D in Fig. 3) is activated. As soon as contact 2 is activated, the brake light is switched on. For further pedal travel up to 30 mm, contact 2 remains activated and this corresponds to low gradient. This information is conveyed to the EPB controller. Even further pedal travel (i.e. beyond 30mm) activates contact 1 (marked as A and B in Fig. 3) and corresponds to high gradient. This is also conveyed to the EPB controller. The FIG. 4, illustrates a flow chart depicting the method for determining pedal travel using three contact positions in accordance with some embodiments of the present invention.

Referring to FIG. 5 and 6, a representation of brake light switch mounting location is illustrated in accordance with some embodiments of the present invention. The Fig. 5 shows the side view of the pedal box assembly showing the brake light switch (1) and the brake pedal (4). The movement (5) of the BLS plunger (2) is indicated and this will be in proportion to the movement of the brake pedal (20).

In an embodiment of the present disclosure, Hill-Hold / Auto-Hold function can be given even on Non-ESP vehicles. The stand-alone G-sensor has packaging issues as it needs to be positioned at vehicle Center of Gravity (CG). However, potentiometer / 3-point switch can be easily packaged in pedal box according to an embodiment of the present invention.

According to embodiments of the present invention provides a cost-effective technique as ESP/G-sensor is not required. The system of the present invention provides elimination of G-sensor and its related brackets and wiring harnesses. Consequently, the present invention facilitates smooth implementation of Hill-Hold function on all vehicles.

In accordance with another embodiment of the present invention, there is improvement of liner life as compared to full-apply as high application frequency is drastically reduced.

With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.

It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should typically be interpreted to mean "at least one" or "one or more"); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B."

While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Referral Numerals:
Reference Number Description
1 Brake light switch
2 Brake light switch (BLS) plunger
3 Potentiometer / multi-contact rotary switch
4 Brake pedal
5 Movement of BLS Plunger
6 Connection to Body Control Module (BCM)
7 Electric Park Brake (EPB)
8 Electronic Control Unit (ECU)
9 Position sensor
10 Plunger
11 Pedal mounting bracket
12 Torsion spring
13 Pushed plunger condition
14 Free plunger condition
15 Switch
16 Pushed plunger condition (new)
17 Free plunger high condition
18 Free plunger low condition
19 Battery
20 Movement of Brake Pedal
21 Brake Light (High mounted stop lamp)

Reference Alphabet Description
A, B Contact 1. – Corresponding to Reference No. 17
C, D Contact 2 – Corresponding to Reference No. 18
E, F Contact 3 – Corresponding to Reference No. 16
J, K Contact corresponding to Reference No. 14
G, H Contact corresponding to Reference No. 13
,CLAIMS:We claim:

1. A system for approximating gradient based on pedal travel in the vehicle comprising:
brake pedal mounted on vehicle,
a potentiometer integrated with the said brake pedal,
at least one sensor is located on said brake pedal and configured to transmit signal to body control module (BCM), the said BCM being coupled with a controller; and
an electric park brake (EPB) configured with said BCM to receive information for applying parking brake.
2. The system as claimed in claim 1, wherein said potentiometer being a multi-contact rotary switch consisting one or more positions.
3. The system as claimed in claim 2, wherein said multi-contact rotary switch consisting three contact positions such as contact 1 position or first position, contact 2 position or second position and contact 3 position or third position.
4. The system as claimed in claim 1, wherein a brake light switch operably mounted with the said brake pedal.
5. The system as claimed in claim 1, wherein said brake pedal being provided with torsion spring.
6. A method for approximating gradient based on pedal travel in the vehicle comprises steps of:
actuating brake causing brake pedal to travel,
transmitting information for the brake pedal travel distance to body control module (BCM) using sensor mounted on the brake pedal,
publishing the said information on Controller Area Network (CAN) coupled with said body control module (BCM) in vehicle,
reading the said information by electric park brake (EPB); and
actuating parking brake by EPB based on the said information according to one or more predetermined conditions.
7. The method as claimed in claim 6, wherein said distance travelled by brake pedal being calculated using a potentiometer being operably mounted with brake pedal providing multi-contact rotary switch facilitating one or more contacting positions.
8. The method as claimed in claim 6, wherein said one or more predetermined conditions being level of gradient such as low gradient and high gradient.
9. The method as claimed in claim 7, wherein said multi-contact rotary switch consisting three contact positions where, in contact 3 position or third position, brake being released and brake light being OFF; in contact 2 position or second position, brake being pressed, the brake pedal travels up to a predetermined distance, the brake light glows and the gradient is calculated as low; and in contact 1 position or first position, brake being pressed, the brake pedal travels beyond the predetermined distance and the gradient is calculated as high.
10. The method as claimed in claims 6 and 9, wherein the said contact positions being detected by the potentiometer or multi-contact rotary switch.
11. The method as claimed in claim 9, wherein brake light switch operably mounted with said brake pedal.
12. The method as claimed in claim 11, wherein said brake light switch comprises a movable plunger, upon travelling predetermined distances by the said plunger brake light gets activated and gradient information is calculated.
13. The method as claimed in claim 6, wherein the parking brake application status being indicated by instrument cluster of the vehicle.