DESC:FIELD OF INVENTION

The present invention relates to automotive clutches. In particular, the present invention relates to a device for detecting kiss-point in an automotive clutch. More particularly, the present invention relates to a device for dynamic kiss-point detection in automotive clutches.

BACKGROUND OF THE INVENTION

The Kiss point refers to the value of the control variable for which a friction clutch commences torque transmission. Therefore, for controlling most of the automatic transmissions equipped with wet clutches (for example dual clutch transmission), it is important to pinpoint the Kiss point with high accuracy. This can also reduce wear on components like synchronization rings.

In a single dry clutch, the takeoff point is the hydraulic pressure responsible for starting the clutch piston movement during the filling process. The takeoff point and the Kiss point are distinct points of the filling pressure characteristic and these points can be analytically determined for all phases of this characteristic.

In the existing technology for AMT (Automated Manual Transmission), the clutch kiss-point cannot be detected and updated dynamically in a moving vehicle.

At present, the kiss-point can be updated only after vehicle is brought in a standstill condition and it is updated after cranking. On driving for long durations without stopping the vehicle, the actual kiss-point gets changed, which may lead to clutch slippage and thus, less torque is transmitted to the vehicle.

PRIOR ART

WO2010063337 (A1) discloses a clutch system for a vehicle with a clutch operating element, a clutch operating position sensor (15) and a clutch actuator unit (3), wherein the clutch actuator unit comprises a clutch control unit which is connected to said sensor, wherein the clutch control unit transfers an operating element position measured by the sensor into a travel path of a first part of the clutch according to a transfer characteristic and wherein a Kiss point detection unit (19,20,21) is provided that detects when the first part (5) of the clutch makes contact with a second part (5) of the clutch in order to transfer torque and wherein the Kiss point detection unit communicates with the clutch control unit and the clutch control unit changes the transfer characteristic when the Kiss point has changed. By the invention, a convenient way for wear adjustment is provided.

However, it discloses a Kiss point detection unit detecting the kissing point periodically or constantly during the operating time, every time the engine is started and does not disclose dynamically detecting and updating the kissing point in a moving vehicle.

DISADVANTAGES WITH THE PRIOR ART

The following are the main disadvantages of the existing technology for AMT (Automated Manual Transmission):

• Clutch kiss-point cannot be detected and updated dynamically in a moving vehicle.

• Kiss-point can be updated only after vehicle is brought in a standstill condition and updated after cranking.

• Actual kiss-point is changed while driving for long durations without stopping the vehicle.

• Clutch slippage occurs.

• Lesser torque transmission to the vehicle due to excessive slippage of the clutch.

Therefore, there is an existing need for dynamically monitoring the clutch kiss-point in a moving vehicle, which can facilitate in a continuous adjustment of the clutch position without any need for switching off the vehicle for bringing it in a standstill position. It would be particularly beneficial in the traffic conditions prevailing in Indian scenario, in which the vehicle constantly stops and moves.
OBJECTS OF THE INVENTION

Some of the objects of the present invention - satisfied by at least one embodiment of the present invention - are as follows:

An object of the present invention is to provide an accurate dynamic clutch kiss-point detection device for automotive vehicles.

Another object of the present invention is to provide a dynamic clutch kiss-point detection device for automotive vehicles, which has a higher durability.

Still another object of the present invention is to provide a dynamic clutch kiss-point detection device, which is reliable even in moving conditions of vehicles without switching-off the vehicle.

Yet another object of the present invention is to provide a dynamic clutch kiss-point detection device for automotive vehicles, which increases the life-cycle by automatically updating the clutch kiss-point in dynamic traffic conditions.

A further object of the present invention is to provide a dynamic clutch kiss-point detection device for automotive vehicles, which limits the clutch slippage.

A still further object of the present invention is to provide a dynamic clutch kiss-point detection device for automotive vehicles, which continuously updates the clutch kiss-point position.

These and other objects and advantages of the present invention will become more apparent from the following description when read with the accompanying figures of drawing, which are, however, not intended to limit the scope of the present invention in any way.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a dynamic Kiss point monitoring, detection and adjustment device in automotive clutch for an automated manual transmission (AMT), the device comprising:
• an automated Manual Transmission (AMT);

• a clutch pack;

• a clutch actuation unit;

• a flywheel; and

• a transmission control unit (TCU);

wherein the Kiss point of the automotive clutch is continuously detected and accurately adjusted to a predetermined nominal Kiss point value preset between a minimum Kiss point value and a maximum Kiss point value, by means of the TCU while the vehicle is in motion.

Typically, the Kiss point of the automotive clutch is continuously detected and accurately adjusted based on the RPM thereof.

Typically, the Kiss point of the automotive clutch is continuously detected and accurately adjusted based on the torque thereof.

Typically, the Kiss point detection and adjustment is triggered by the TCU under the following conditions:

a) the detected clutch rpm is higher than the minimum threshold value thereof; and
b) the detected clutch rpm is lower than the maximum threshold value thereof;

wherein in the absence of error in memory, the clutch rpm is monitored until reaching the maximum threshold value thereof or until detecting a timeout.

Typically, the vehicle is crawling with a speed of greater than 0 km/h defined for a de-bounce time and with a speed less than the threshold value thereof defined in the TCU, preferably a speed of about 5 km/h.

Typically, the accelerator pedal position is greater than a preset point, preferably about 1% and is less than a threshold value predefined in the TCU, preferably about 35%.
In accordance with the present invention, there is also provided a method for monitoring, detecting and adjusting the Kiss point by using a dynamic Kiss point detection device as claimed in anyone of claims 1 to 6, the method comprising the steps of:

• calculating the clutch Kiss point as the difference between the closed clutch position and actual clutch position;

• introducing a temporary or instantaneous Kiss Point working from the point of inflection, not updated instantaneously;

• finding a valid closed clutch position before picking a new kiss-point;

• stepped increase in value on meeting the conditions and with changed temperature value, the increment being made according to a filter;

• complying with above conditions for arriving at the defined counter threshold value; and

• updating clutch Kiss-point along with the closed clutch position on reaching the aforesaid defined counter threshold value.

Typically, the Kiss point detection and adjustment are triggered by the TCU under the following conditions:

a) the clutch torque is higher than the minimum threshold value thereof; and

b) the clutch rpm is less than the maximum threshold value thereof;

wherein in the absence of error in memory, the clutch torque is monitored until reaching the maximum threshold value thereof or until detecting a timeout.

A method for monitoring, detecting and adjusting the Kiss point by using a dynamic Kiss point detection device as claimed in claim 8, wherein the method comprises the steps of:

• Calculating the clutch Kiss point as the difference between the closed clutch position and actual clutch position; and

• Calculating the torque as the product of inertia and angular velocity.

Typically, the method further comprises the steps of:

• Launching the vehicle from the standstill condition until the TCU registers the toque of about 2 N-m;

• Calibrating the threshold value for manoeuvre repeatability to update the Kiss point; and

• Introducing two variables, considering the first variable as the final saved value in EEPROM and the second variable as a temporary value (kisstmp).

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

The present invention will be briefly described with reference to the accompanying drawings, which include:

Figure 1 shows a flow-chart of the dynamic clutch kiss-point detection device for automotive vehicles configured in accordance with the present invention. It shows four different events during the working thereof.

Figure 2 shows the comparative clutch positions for a new clutch, a nominal clutch and a worn-out clutch indicated from a set kiss-point thereof.

DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS

In the following, different embodiments of the present invention will be described in more details with reference to the accompanying drawings without limiting the scope and ambit of the present invention in any way.

Figure 1 shows a flow-chart of the dynamic clutch kiss-point detection device for automotive vehicles configured in accordance with the present invention. It shows four different events A, B, C and D during the working thereof. Here, event A represents the condition of the vehicle in which the vehicle is in standstill condition, with engine on, gear engaged, accelerator pedal inactive and brake applied. Event B represents a vehicle brought from stand still position (event A) to crawling condition by releasing the brake. Finally, event C represents the vehicle launching condition, in which the engine is running with gear engaged, brake released, and accelerator pedal depressed to launch the vehicle in motion. Event D represents the vehicle being brought again in idle condition thereof by applying the brake, gear still in engagement and by releasing the accelerator pedal completely to restore it to a non-active condition.

Figure 2 shows the comparative clutch positions for a new clutch, a nominal clutch and a worn-out clutch indicated from a set-point thereof. It is evident here that a new clutch has a minimum kiss-point value and a worn-out clutch has a maximum kiss-point value. The nominal clutch kiss-point value lies somewhere in between these two extreme values. Here, by using clutch design data, the maximum and minimum kiss-point values can be populated and usually these maximum and minimum values are defined by the design tolerances.

DESCRIPTION OF THE PRESENT INVENTION

The dynamic kiss-point detection device for automotive clutches configured in accordance with the present invention comprises the following main components:
• Automated Manual Transmission Kit,

• Clutch Pack,

• Clutch Actuation Kit,

• Flywheel, and

• Transmission Control Unit (TCU).

Accordingly, the dynamic kiss-point detection device for automotive clutches configured in accordance with the present invention leads to higher durability, reliability and accurate clutch kiss-point detection even when the vehicle is in a dynamic or moving condition.

There is a possibility of detecting the clutch kiss-point by using either the RPM-based kiss-detection condition or by using a torque-based kiss-detection condition.

RPM-BASED KISS DETECTION CONDITIONS:

Here, the dynamic Kiss point detection is active only during Event C of Fig. 1. The triggering Conditions for this are as under:

a) Actual Clutch rpm greater than minimum threshold value of clutch rpm.

b) Actual Clutch rpm less than maximum threshold value of Clutch rpm.

• Clutch rpm needs to be monitored only till the maximum threshold value of the Clutch rpm or a timeout is detected.

• Vehicle speed of greater than 0 km/h is defined for a de-bounce time.

• Vehicle speed less than the defined threshold value of the vehicle speed, for example: 5 km/h.

• Accelerator pedal position is greater than the set point, e.g. 1%.

• Accelerator pedal position is less than threshold value, e.g. 35%.

• Logic will only be active if the previous state was Crawling and there is NO error present in the memory.

• Here, Clutch Kiss point = Closed Clutch Position - Actual Clutch position.

c) If a temporary Kiss Point (Instantaneous Kiss Point) is introduced, it works from the point of inflection, but is not updated instantaneously.

d) A valid clutch closed position is found before picking a new kiss-point.

e) On meeting the conditions and with changed temperature value, the increment occurs according to a filter (for stepped increase in value).

f) Above conditions are complied with for defined counter threshold value.

g) On reaching the defined counter threshold value, the Kiss-point along with the closed clutch position is updated.

TORQUE-BASED KISS DETECTION CONDITIONS:

Here, the dynamic Kiss point detection is active both during Events A and C. The triggering conditions for this are as under:

c) Actual Clutch Torque greater than minimum clutch torque threshold.

d) Actual Clutch rpm less than maximum threshold value of the Clutch rpm.

• Clutch torque needs to be monitored only up to the maximum threshold value of the Clutch torque or for a Timeout.

• There should be NO error present in the memory.

• Here, Kiss point = Closed Clutch Position - Actual Clutch position, and

• Torque = Inertia * Angular Velocity.

e) The vehicle is launched from the standstill condition and TCU registers the clutch position to start getting about 2 Nm torque.

f) Obtain the Calibration threshold value for the manoeuvre repeatability to update the kiss-point.

g) Two variables are introduced, the first is considered as the final saved value in EEPROM (a read-only memory whose contents can be erased and reprogrammed using a pulsed voltage) and the second as a temporary value (kisstmp).

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE

The dynamic kiss-point detection device for automotive clutches configured in accordance with the present invention has the following advantages:
? Accurately detects the dynamic clutch kiss-point for automotive vehicle clutches.

? Ensures higher durability.

? Highly reliable even in moving conditions of vehicles.

? Increases the life-cycle by automatically updating the clutch kiss-point in dynamic traffic conditions.

? Limits the clutch slippage.

? Continuously updates the clutch kiss-point position.

In the previously detailed description, different features have been summarized for improving the conclusiveness of the representation in one or more examples. However, it should be understood that the above description is merely illustrative, but not limiting under any circumstances. It helps in covering all alternatives, modifications and equivalents of the different features and exemplary embodiments.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept. Many other examples are directly and immediately clear to the skilled person because of his/her professional knowledge in view of the above description.

These innumerable changes, variations, modifications, alterations may be made and/or integrations in terms of materials and method used may be devised to configure, manufacture and assemble various constituents, components, subassemblies and assemblies according to their size, shapes, orientations and interrelationships. Therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments.

The exemplary embodiments described in this specification are intended merely to provide an understanding of various manners in which this embodiment may be used and to further enable the skilled person in the relevant art to practice this invention. The description provided herein is purely by way of example and illustration.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, shall be understood to implies including a described element, integer or method step, or group of elements, integers or method steps, however, does not imply excluding any other element, integer or step, or group of elements, integers or method steps. In the claims and the description, the terms “containing” and “having” are used as linguistically neutral terminologies for the corresponding terms “comprising”.

The use of the expression “a”, “at least” or “at least one” shall imply using one or more elements or ingredients or quantities, as used in the embodiment of the disclosure in order to achieve one or more of the intended objects or results of the present invention. Furthermore, the use of the term “one” shall not exclude the plurality of such features and components described.

The numerical values given of various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the disclosure unless there is a statement in the specification to the contrary.

Also, any reference herein to the terms ‘left’ or ‘right, ‘up’ or ‘down, or ‘top’ or ‘bottom’ are used as a matter of mere convenience, and are determined by standing at the rear of the machine facing in its normal direction of travel.

The various features and advantageous details are explained with reference to the non-limiting embodiment/s in the above description in accordance with the present invention.

The descriptions of well-known components and manufacturing and processing techniques are consciously omitted in this specification, so as not to unnecessarily obscure the specification.

Furthermore, the various components shown or described herein for any specific application of this invention can be widely known or used in the art by persons skilled in the art and each will likewise not therefore be discussed in significant detail. When referring to the figures, like parts are numbered the same in all of the figures. ,CLAIMS:We claim:

1. A dynamic Kiss point monitoring, detection and adjustment device in automotive clutch for an automated manual transmission (AMT), said device comprising:

• Automated Manual Transmission;

• Clutch Pack;

• Clutch Actuation unit;

• Flywheel; and

• Transmission Control Unit (TCU);

wherein the Kiss point of said automotive clutch is continuously detected and accurately adjusted to a predetermined nominal Kiss point value preset between a minimum Kiss point value and a maximum Kiss point value, by means of said TCU while the vehicle is in motion.

2. Device as claimed in claim 1, wherein the kiss-point of said automotive clutch is continuously detected and accurately adjusted based on the RPM thereof.

3. Device as claimed in claim 1, wherein the kiss-point of said automotive clutch is continuously detected and accurately adjusted based on the torque thereof.

4. Device as claimed in claim 2, wherein the Kiss point detection and adjustment is triggered by said TCU under the following conditions:

b) the detected clutch rpm is higher than the minimum threshold value thereof; and
b) the detected clutch rpm is lower than the maximum threshold value thereof;

wherein in the absence of error in memory, the clutch rpm is monitored until reaching the maximum threshold value thereof or until detecting a timeout.

5. Device as claimed in claim 4, wherein the vehicle is crawling with a speed of greater than 0 km/h defined for a de-bounce time and with a speed less than the threshold value thereof defined in said TCU, preferably a speed of about 5 km/h.

6. Device as claimed in claim 5, wherein the accelerator pedal position is greater than a preset point, preferably about 1% and is less than a threshold value predefined in said TCU, preferably about 35%.

7. A method for monitoring, detecting and adjusting the Kiss point by using a device as claimed in anyone of claims 1 to 6, the method comprising the steps of:
• Calculating the clutch Kiss point as the difference between the closed clutch position and actual clutch position;

• Introducing a temporary or instantaneous Kiss Point working from the point of inflection, not updated instantaneously;

• Finding a valid closed clutch position before picking a new kiss-point;

• Stepped increase in value on meeting the conditions and with changed temperature value, the increment being made according to a filter;

• Complying with above conditions for arriving at the defined counter threshold value; and

• Updating clutch Kiss-point along with the closed clutch position on reaching the aforesaid defined counter threshold value.

8. Device as claimed in claim 3, wherein the Kiss point detection and adjustment is triggered by said TCU under the following conditions:

a) the clutch torque is higher than the minimum threshold value thereof; and
b) the clutch torque is less than the maximum threshold value thereof;

wherein in the absence of error in memory, the clutch torque is monitored until reaching the maximum threshold value thereof or until detecting a timeout.

9. A method for monitoring, detecting and adjusting the Kiss point by using a device as claimed in claim 8, said method comprising the steps of:

• calculating the clutch Kiss point as the difference between the closed clutch position and actual clutch position; and

• calculating the torque as the product of inertia and angular velocity;

10. Method as claimed in claim 9, said method comprising the steps of:

• Launching the vehicle from the standstill condition until said TCU registers the toque of about 2 N-m;

• Calibrating the threshold value for manoeuvre repeatability to update the Kiss point; and

• Introducing two variables, considering the first variable as the final saved value in EEPROM and the second variable as a temporary value (kisstmp).

Dated: this 19th day of January 2017. SANJAY KESHARWANI
APPLICANT’S PATENT AGENT