Claims:We Claim:
1. A method (200) for powertrain decoupling in automated manual transmission, the method comprises:
Receiving (202), by Transmission Control Unit (TCU) (101), a first operational parameter, a second operational parameter and a third operational parameter determined by an electronic stability programming controller (ESP) (103);
Determining (204), by the transmission control unit, an effective operational parameter from the received first operational parameter;
Determining (206), by the Transmission Control Unit (101), a first vehicle stall tendency estimation based on the determined effective operational parameter, the received second operational parameter and a pre-set mapping between the effective operational parameter and the second operational parameter stored in memory (102) operatively connected to the transmission control unit (101);
Determining (208), by the Transmission Control Unit (101), a second vehicle stall tendency estimation based on the received second operational parameter, the third operational parameter and a pre-set mapping between the second operational parameter and the third operational parameter stored in the memory (102) operatively connected to the transmission control unit (101); and
Decoupling (210), by the Transmission Control Unit (101), the powertrain based on the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation, wherein decoupling of the powertrain is performed by the transmission control unit (101) only when the determined first vehicle stall tendency estimation is identical to the second vehicle stall tendency estimation.
2. The method (200) as claimed in claim 1, wherein the first operational parameter is front and rear wheel speeds, the second operational parameter is master cylinder pressure, the third operational parameter is vehicle negative pitching angle and the effective operational parameter is change in front and rear wheel deceleration depicting difference between the front wheel deceleration and the rear wheel deceleration.
3. The method (200) as claimed in claim 1, wherein the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation is either of low stall tendency or moderate stall tendency or high stall tendency.
4. The method (200) as claimed in claim 1, wherein the powertrain decoupling is done at idle engine speed and engine braking is applied till the vehicle speed recedes to the value corresponding to the idle engine speed (Th1) when the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation is low stall tendency.
5. The method (200) as claimed in claim 1, wherein the powertrain decoupling is done at a first decoupling engine speed (Th2) and the engine braking is applied till the vehicle speed recedes to the value corresponding to a first decoupling engine speed when the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation is moderate stall tendency.
6. The method (200) as claimed in claim 1, wherein the powertrain decoupling is done at a second decoupling engine speed (Th3) and the engine braking is applied till the vehicle speed recedes to the value corresponding to a second decoupling engine speed (Th3) when the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation is high stall tendency.
7. The method (200) as claimed in claims 4 to 6, wherein the second decoupling Engine speed (Th3) is greater than the first decoupling Engine speed (Th2) and the first decoupling engine speed (Th2) is greater than the idle engine speed (Th1).
8. A system (100) for powertrain decoupling in automated manual transmission, the system (100) comprising:
an electronic stability programming controller (ESP) (103) configured to determine and send a first operational parameter, a second operational parameter and a third operational parameter; and
a transmission control unit (101) configured to:
receive a first operational parameter, a second operational parameter and a third operational parameter determined by the electronic stability programming controller (ESP) (103);
determine an effective operational parameter from the received first operational parameter;
determine a first vehicle stall tendency estimation based on the determined effective operational parameter, the received second operational parameter and a pre-set mapping between the first operational parameter and the second operational parameter stored in memory (102) operatively connected to the transmission control unit (101);
determine a second vehicle stall tendency estimation based on the received second operational parameter, the third operational parameter and a pre-set mapping between the second operational parameter and the third operational parameter stored in the memory (102) operatively connected to the transmission control unit (101); and
decouple the powertrain based on the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation, wherein decoupling of the powertrain is performed by the transmission control unit (101) only when the determined first vehicle stall tendency estimation is identical to the second vehicle stall tendency estimation.
9. The system (100) as claimed in claim 8, wherein the first operational parameter is front and rear wheel speeds, the second operational parameter is master cylinder pressure, the third operational parameter is vehicle negative pitching angle and the effective operational parameter is change in front and rear wheel deceleration depicting difference between the front wheel deceleration and the rear wheel deceleration.
10. The system (100) as claimed in claim 8, wherein the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation is either of low stall tendency or moderate stall tendency or high stall tendency.
11. The system (100) as claimed in claim 8, wherein the transmission control unit (101) decouple the powertrain at idle engine speed (Th1) and engine braking is applied till the vehicle speed recedes to the value corresponding to an idle engine speed (Th1) when the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation is low stall tendency.
12. The system (100) as claimed in claim 8, wherein the transmission control unit (101) decouples the powertrain at a first decoupling engine speed (Th2) and the engine braking is applied till the vehicle speed recedes to the value corresponding to a first decoupling engine speed (Th2) when the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation is moderate stall tendency.
13. The system (100) as claimed in claim 8, wherein the transmission control unit (101) decouples the powertrain at a second decoupling engine speed (Th3) and the engine braking is applied till the vehicle speed recedes to the value corresponding to a second decoupling engine speed (Th3) when the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation is high stall tendency.
14. The system (100) as claimed in claims 11 to 13, wherein the second decoupling engine speed (Th3) is greater than the first decoupling engine speed (Th2) and the first decoupling engine speed (Th2) is greater than the idle engine speed (Th1).
, Description:A METHOD AND A SYSTEM FOR POWERTRAIN DECOUPLING IN AUTOMATED MANUAL TRANSMISSION

TECHNICAL FIELD
[0001] The present disclosure, in general, relates to an Automated Manual Transmission (AMT). The present disclosure, particularly, relates to a method and a system for powertrain decoupling in automated manual transmission to prevent engine stalling.

BACKGROUND
[0002] Vehicles have powertrain to provide power from engine to driving wheels. A vehicle with two-wheel drive system provides power to two wheels of a vehicle. A two-wheel drive system could be a front wheel drive or a rear wheel drive. In front wheel drive system, the front wheels are connected with powertrain. Similarly, in rear wheel drive system, the rear wheels are connected with powertrain.
[0003] The powertrain mainly comprises an internal combustion engine, a transmission, a power transfer unit for coupling and decoupling of engine from the transmission, and a driveshaft. The operating speed of the internal combustion engine can be reduced through powertrain decoupling by decoupling driveshaft from the internal combustion engine. When the internal combustion engine is decoupled, the driveshaft is rotated by a torque applied by the driving wheels.
[0004] Powertrain decoupling timing is an important factor to decide, while decoupling powertrain from the driving wheels because engine braking assist and engine stall protection depends on powertrain decoupling timing. Engine braking assist is a desired operation when braking is required. In engine braking assist, the vehicle is slow down by limiting air flow and fuel injection to the engine, causing decelerative forces in the engine to decrease the speed at which the wheels are rotating. Contrary to this, engine stalling is an undesirable operation when braking is required. During engine stalling, the engine abruptly ceases to operate and stops turning. It might happen due to engine not getting enough air, energy, fuel, or electric spark, fuel starvation, a mechanical failure or in response to sudden increase in engine load. Engine stalling has major impact on vehicle working, for instance, engine stalling may lead to locking of driving wheels, brake pedals will be difficult to operate, no steering assist or vehicle might become uncontrollable. If the powertrain is decoupled earlier, the engine braking will not be utilized, ultimately leading to requirement of high amount of braking force to slow down the vehicle, causing faster wear of brake pads and increase in stopping distance. Accordingly, timing of powertrain decoupling is usually optimized to take advantage of engine braking assist while avoiding engine stalling.
[0005] In most of the existing automated manual transmission vehicles, the powertrain is decoupled at a fixed engine speed irrespective of the driveshaft resistance level resulting from various aerodynamic, vehicle internal friction and road factors. This may lead to problem of inadequate braking or heavy braking, which might lead to engine stalling.
[0006] Accordingly, there is a need for a method and a system for powertrain decoupling in an automated manual transmission, to prevent engine stalling by estimating engine stall tendency, to improve engine stall prevention and engine braking assist performance for all driveshaft resistances.

SUMMARY
[0007] This summary is provided to introduce concepts related to a method and a system for powertrain decoupling in automated manual transmission. The concepts are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
[0008] The present subject matter relates to a method for powertrain decoupling in automated manual transmission. The method comprises in the first step receiving, by Transmission Control Unit (TCU), a first operational parameter, a second operational parameter and a third operational parameter determined by an electronic stability programming controller (ESP). In the second step, determining, by the transmission control unit, an effective operational parameter from the received first operational parameter. In the third step, determining, by the Transmission Control Unit, a first vehicle stall tendency estimation based on the determined effective operational parameter, the received second operational parameter and a pre-set mapping between the effective operational parameter and the second operational parameter stored in memory operatively connected to the transmission control unit. In the fourth step determining, by the Transmission Control Unit, a second vehicle stall tendency estimation based on the received second operational parameter, the third operational parameter and a pre-set mapping between the second operational parameter and the third operational parameter stored in the memory. In the fifth step, decoupling, by the Transmission Control Unit, the powertrain based on the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation, wherein decoupling of the powertrain is performed only when the determined first vehicle stall tendency estimation is identical to the second vehicle stall tendency estimation.
[0009] In an aspect, the first operational parameter is front and rear wheel speeds, the second operational parameter is master cylinder pressure, the third operational parameter is vehicle negative pitching angle and the effective operational parameter is change in front and rear wheel decelerations. (determined by transmission control unit)
[0010] In an aspect, the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation is either of low stall tendency or moderate stall tendency or high stall tendency.
[0011] In an aspect, the powertrain decoupling is done at idle engine speed and engine braking is applied till the vehicle speed recedes to the value corresponding to idle engine speed, when the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation is low stall tendency.
[0012] In an aspect, the powertrain decoupling is done at a first decoupling speed and the engine braking is applied till the vehicle speed recedes to the value corresponding to the first decoupling engine speed, when the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation is moderate stall tendency.
[0013] In an aspect, the powertrain decoupling is done at a second decoupling speed and the engine braking is applied till the vehicle speed recedes to the value corresponding to the second decoupling engine speed, when the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation is high stall tendency.
[0014] In an aspect, the second decoupling engine speed is greater than the first decoupling engine speed and the first decoupling engine speed is greater than the idle engine speed.
[0015] The present subject matter further relates to a system for powertrain decoupling in automated manual transmission. The system comprises an electronic stability programming controller (ESP) and a transmission control unit. The electronic stability programming controller (ESP) configured to determine a first operational parameter, a second operational parameter and a third operational parameter. The transmission control unit configured to receive a first operational parameter, a second operational parameter and a third operational parameter determined by the electronic stability programming controller (ESP). The transmission control unit is further configured to determine an effective operational parameter from the received first operational parameter. The transmission control unit is further configured to determine a first vehicle stall tendency estimation based on the determined effective operational parameter, the received second operational parameter and a pre-set mapping between the first operational parameter and the second operational parameter stored in memory. The transmission control unit is further configured to determine a second vehicle stall tendency estimation based on the received second operational parameter, the third operational parameter and a pre-set mapping between the second operational parameter and the third operational parameter stored in the memory. The transmission control unit is further configured to decouple the powertrain based on the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation. Decoupling of the powertrain is performed by the transmission control unit only when the determined first vehicle stall tendency estimation is identical to the second vehicle stall tendency estimation.
[0016] In an aspect, the first operational parameter is front and rear wheel speed, the second operational parameter is master cylinder pressure, the third operational parameter is vehicle negative pitching angle and the effective operational parameter is change in front and rear wheel deceleration.
[0017] In an aspect, the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation is either of low stall tendency or moderate stall tendency or high stall tendency.
[0018] In an aspect, the transmission control unit decouple the powertrain at idle engine speed and engine braking is applied till the vehicle speed recedes to the value corresponding to the idle engine speed when the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation is low stall tendency.
[0019] In an aspect, the transmission control unit decouples the powertrain at a first decoupling engine speed and the engine braking is applied till the vehicle speed recedes to the value corresponding to the first decoupling engine speed when the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation is moderate stall tendency.
[0020] In an aspect, the transmission control unit decouples the powertrain at a second decoupling engine speed and the engine braking is applied till the vehicle speed recedes to value corresponding to a second decoupling engine speed when the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation is high stall tendency.
[0021] In an aspect, the second decoupling engine speed is greater than the first decoupling engine speed and the first decoupling engine speed is greater than the idle engine speed.
[0022] To further understand the characteristics and technical contents of the present subject matter, a description relating thereto will be made with reference to the accompanying drawings. However, the drawings are illustrative only but not used to limit the scope of the present subject matter.
[0023] Various objects, features, aspects, and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF FIGURES
[0024] The illustrated embodiments of the present disclosure will be best understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and processes that are consistent with the subject matter as claimed herein, wherein:
[0025] FIG. 1 illustrates an exemplary system for powertrain decoupling in automated manual transmission that can be utilized to implement one or more exemplary embodiments of the present disclosure;
[0026] FIG. 2 illustrates a flow chart of the method 200 for powertrain decoupling in automated manual transmission that can be utilized to implement one or more exemplary embodiments of the present disclosure;
[0027] FIG. 3a illustrates an exemplary pre-set mapping between the effective operational parameter and the second operational parameter stored in the memory operatively connected to the transmission control unit as per vehicle specifications of exemplary vehicle; and
[0028] FIG. 3b illustrates an exemplary pre-set mapping between the second operational parameter and the third operational parameter stored in the memory operatively connected to the transmission control unit as per vehicle specifications of exemplary vehicle.
[0029] The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed, without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION
[0030] A few aspects of the present disclosure are explained in detail below with reference to the various figures. Example implementations are described to illustrate the disclosed subject matter, not to limit its scope, which is defined by the claims. Those of ordinary skill in the art will recognize a number of equivalent variations of the various features provided in the description that follows.

EXEMPLARY IMPLEMENTATIONS
[0031] While the present disclosure may be embodied in various forms, there are shown in the drawings, and will hereinafter be described, some exemplary and non-limiting embodiments, with the understanding that the present disclosure is to be considered an exemplification of the invention and is not intended to limit the invention to the specific embodiments illustrated. Not all of the depicted components described in this disclosure may be required, however, and some implementations may include additional, different, or fewer components from those expressly described in this disclosure. Variations in the arrangement and type of the components may be made without departing from the scope of the claims as set forth herein.
[0032] Some embodiments of this invention, illustrating all its features, will be discussed in detail.
[0033] The techniques described below may be implemented using one or more computer programs executed on (or executable by) a programmable computer including any combination of any number of the following: a processor, a sensor, a storage medium readable and/or writable by the processor (including for example volatile and non-volatile memory and/or storage elements), plurality of inputs units, plurality of output devices and networking devices.
[0034] Method steps as disclosed by present disclosure may be performed by one or more computer processors executing a program tangibly embodied on a computer-readable medium to perform functions of the invention by operating on input and generating output. Suitable processors include, by way of example, both general and special purpose microprocessors. Generally, the processor receives (reads) instructions and content from a memory (such as a read only memory and/or random access memory) and writes (stores) instructions and content to the memory. Storage devices suitable for tangibly embodying computer program instructions and content include, for example, all forms of non-volatile memory, such as semiconductor memory devices, including EPROM, EEPROM, and flash memory devices; magnetic disks such as internal hard disk and removable disks, magneto-optical disks, and CD-ROMs. Any of the foregoing may be supplemented by, or incorporated in, specially-designed ASICs (application specific integrated circuits) or FPGAs (Field-Programmable Gate Arrays).
[0035] Any content disclosed herein may be implemented, for example, in one or more content structures tangibly stored on a non-transitory computer-readable medium. Embodiments of the invention may store such content in such content structure(s) and read such content from such content structure(s).
[0036] The present disclosure provides a method and a system for powertrain decoupling in automated manual transmission.
[0037] FIG. 1 illustrates an exemplary system for powertrain decoupling in automated manual transmission that can be utilized to implement one or more exemplary embodiments of the present disclosure. The system 100 comprises a transmission control unit 101, a memory 102, an electronic stability programming controller 103 and a powertrain 104. The powertrain comprises an internal combustion engine, a transmission, a power transfer unit for coupling and decoupling of engine from the transmission, and a driveshaft.
[0038] The electronic stability programming controller 103 is configured to determine and send a first operational parameter, a second operational parameter and a third operational parameter. The operational parameters are quantitative determinant of various forces acting on the driving system. In an aspect, the first operational parameter is front and rear wheel speeds. In an aspect, the second operational parameter is a master cylinder pressure. The second operational parameter aids in obtaining the magnitude of brake pedal force. In an aspect, the third operational parameter is a vehicle negative pitching angle. The third operational parameter aids in obtaining the magnitude of vehicle body inertia. The electronic stability programming controller 103 is further configured to send the determined first operational parameter, the second operational parameter and the third operational parameter to the transmission control unit 101.
[0039] The transmission control unit 101 is configured to receive the first operational parameter, the second operational parameter and the third operational parameter from the electronic stability programming controller 103. The transmission control unit is configured to determine change in front and rear wheel deceleration from the received first operational parameter. Particularly, the transmission control unit is configured to determine difference between the front wheel deceleration and the rear wheel deceleration. The determined change in front and rear wheel deceleration is an effective operational parameter which aids in obtaining the magnitude of driving shaft and driven shaft resistances. The transmission control unit 101 is operatively connected to the memory 102. A pre-set mapping between the second operational parameter and the third operational parameter is stored in the memory 102. In other words, a pre-set mapping between the master cylinder pressure and change in the vehicle negative pitching angle is stored in the memory 102. The pre-set mapping between the master cylinder pressure and change in the vehicle negative pitching angle is further divided into various zones depicting the estimation of engine stall tendency. The zones are divided into low engine stall tendency zone, moderate engine stall tendency zone and high engine stall tendency zone. The boundary conditions of the different zones are based on the vehicle specification. Accordingly, the boundary of different zones may vary from vehicle to vehicle.
[0040] A pre-set mapping between the effective operational parameter and the second operational parameter is stored in the memory 102. In other words, a pre-set mapping between change in the front and rear wheel deceleration and master cylinder pressure is stored in the memory 102. The pre-set mapping between change in the front and rear wheel deceleration and master cylinder pressure is further divided into various zones depicting the estimation of engine stall tendency. The zones are divided into low engine stall tendency zone, moderate engine stall tendency zone and high engine stall tendency zone. The boundary conditions of the different zones are based on the vehicle specification. Accordingly, the boundary of different zones may vary from vehicle to vehicle.
[0041] The transmission control unit 101 is further configured to determine a first vehicle stall tendency estimation based on the determined effective operational parameter and received second operational parameter and the pre-set mapping between the effective operational parameter and the second operational parameter stored in the memory 102. Thus, the transmission control unit 101 takes into account the change in front and rear wheel deceleration and the master cylinder pressure to determine a first vehicle stall tendency estimation. It is to be noted that the first vehicle stall tendency estimation is determined in real-time. The first vehicle stall tendency estimation can be classified into either one of the low engine stall tendency, moderate engine stall tendency and high engine stall tendency.
[0042] The transmission control unit 101 is further configured to determine a second vehicle stall tendency estimation based on the received second operational parameter, the third operational parameter and the pre-set mapping between the second operational parameter and the third operational parameter stored in the memory 102. Thus, the transmission control unit takes into account the master cylinder pressure and change in the vehicle negative pitching angle to determine a second vehicle stall tendency estimation. It is to be noted that the second vehicle stall tendency estimation is done in real-time. The second vehicle stall tendency estimation can be classified into either one of the low engine stall tendency, moderate engine stall tendency and high engine stall tendency.
[0043] The transmission control unit 101 is further configured to decouple the powertrain based on the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation. In an aspect, decoupling of the powertrain is performed only when the determined first vehicle stall tendency estimation is identical to the second vehicle stall tendency estimation. Accordingly, three conditions for decoupling of powertrain from driving wheels exist. The three conditions are shown in table 1 below:
Engine stall tendency zone Powertrain decoupling engine speed Engine braking usage
Low N< Th1 High
Moderate Th1 < N < Th2 Moderate
High N < Th3 Low
Th1 is Idle engine speed which is a calibratable value decided based on vehicle specification.
Th2 is first decoupling speed based on engine and vehicle inertia.
Th3 is second decoupling speed based on engine and vehicle inertia.
Th1< Th2 < Th3
CASE-I
When the determined first vehicle stall tendency and the determined second vehicle stall tendency estimation is low stall tendency:
The powertrain decoupling is done at idle engine speed and engine braking is applied till the vehicle speed recedes to the idle engine speed.
CASE-II
When the determined first vehicle stall tendency and the determined second vehicle stall tendency estimation is moderate stall tendency:
The powertrain decoupling is done at first decoupling engine speed and engine braking is applied till the vehicle speed recedes to the first decoupling engine speed.
CASE-III
When the determined first vehicle stall tendency and the determined second vehicle stall tendency estimation is high stall tendency:
The powertrain decoupling is done at second decoupling engine speed and engine braking is applied till the vehicle speed recedes to the second decoupling engine speed.
[0044] The second decoupling engine speed is greater than the first decoupling engine speed and the first decoupling engine speed is greater than the idle engine speed.
[0045] FIG. 2 illustrates a flow chart of the method 200 for powertrain decoupling in automated manual transmission that can be utilized to implement one or more exemplary embodiments of the present disclosure.
[0046] At block 202, the method 200 includes receiving a first operational parameter, a second operational parameter and a third operational parameter by the transmission control unit 101. The first operational parameter, the second operational parameter and the third operational parameter are determined by the electronic stability programming controller (ESP) 103. In an aspect, the first operational parameter is front and rear wheel speeds, the second operational parameter is master cylinder pressure and the third operational parameter is vehicle negative pitching angle. These parameters are send by the electronic stability programming controller 103 to the transmission control unit 101. A pre-set mapping between the second operational parameter and the third operational parameter is stored in the memory 102 operatively connected to the transmission control unit 101. A pre-set mapping between an effective operational parameter and the second operational parameter is stored in the memory 102 operatively connected to the transmission control unit 101.
[0047] At block 204, the method 200 includes determining an effective operational parameter from the received first operational parameter by the transmission control unit (101). A pre-set mapping between the second operational parameter and the third operational parameter is stored in the memory 102 operatively connected to the transmission control unit 101. A pre-set mapping between the effective operational parameter and the second operational parameter is stored in the memory 102 operatively connected to the transmission control unit 101.
[0048] At block 206, the method 200 includes determining a first vehicle stall tendency estimation based on the determined effective operational parameter, the received second operational parameter and the pre-set mapping between the first operational parameter and the second operational parameter stored in the memory 102 operatively connected to the transmission control unit 101. The determined first vehicle stall tendency estimation is either of low stall tendency or moderate stall tendency or high stall tendency.
[0049] At block 208, the method 200 includes determining a second vehicle stall tendency estimation based on the received second operational parameter, the third operational parameter and the pre-set mapping between the second operational parameter and the third operational parameter stored in the memory 102 operatively connected to the transmission control unit 101. The determined second vehicle stall tendency estimation is either of low stall tendency or moderate stall tendency or high stall tendency.
[0050] At block 210, the method 200 includes decoupling the powertrain based on the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation. The decoupling of the powertrain is performed only when the determined first vehicle stall tendency estimation is identical to the second vehicle stall tendency estimation.
[0051] Description related to FIG. 1 has already been discussed, in detail, the first operating parameter, the second operating parameter, the third operating parameters, the effective operational parameter, the first vehicle stall tendency estimation and the second vehicle stall tendency estimation. The method 200 works in the same way as already discussed for the system 100. Therefore, for the sake of brevity, these terms in method 200 have not being explained again.
WORKING EXAMPLE 1
[0052] FIG. 3a illustrates an exemplary pre-set mapping between the effective operational parameter and the second operational parameter stored in the memory operatively connected to the transmission control unit as per vehicle specifications of exemplary vehicle.
[0053] FIG. 3b illustrates an exemplary pre-set mapping between the second operational parameter and the third operational parameter stored in the memory operatively connected to the transmission control unit as per vehicle specifications of exemplary vehicle.
[0054] To begin with, the transmission control unit 101 receives a first operational parameter, a second operational parameter and a third operational parameter from the electronic stability programming controller 103 and determine an effective operational parameter based on the received first operational parameter. Let us consider that the input received as operational parameters are:
Change in Front & Rear wheel Deceleration: 1m/s2 (difference between front wheel deceleration and rear wheel deceleration).
Master Cylinder Pressure: 50 bar.
Vehicle negative Pitching Angle: -0.1g.
Engine idle speed: 1000 RPM.
Engine running speed: 3500 RPM
The transmission control unit 101 determines the First vehicle stall tendency estimation and the second vehicle stall tendency estimation. The transmission control unit determine the first vehicle stall tendency estimation based on the determined first operational parameter, the received second operational parameter and a pre-set mapping between the effective operational parameter and the second operational parameter as shown in FIG. 3a. The transmission control unit determines the second vehicle stall tendency estimation based on the received second operational parameter, the third operational parameter and a pre-set mapping between the second operational parameter and the third operational parameter as shown in FIG. 3b. Let us assume that the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation falls in the low stall tendency zone.
First vehicle stall tendency estimation: Low stall tendency as per FIG. 3a
Second vehicle stall tendency estimation: Low stall tendency as per FIG. 3b
[0055] In low stall tendency, the transmission control unit 101 have more time to decouple the powertrain and inertia of engine will avoid engine stalling up to idle speed of the engine. Then powertrain can be decoupled at the lowest possible engine speed (idle speed) (Th1) e.g. 1000 rpm. If the vehicle decelerated from 3500 rpm then engine braking was used from 3500 – 1000 rpm.
WORKING EXAMPLE 2
[0056] To begin with, the transmission control unit 101 receives a first operational parameter, a second operational parameter and a third operational parameter from the electronic stability programming controller 103 and determines an effective operational parameter based on the received first operational parameter. Let us consider that the input received as operational parameters are:
Change in Front & Rear wheel Deceleration: 3m/s2 (difference between front wheel deceleration and rear wheel deceleration).
Master Cylinder Pressure: 100bar.
Vehicle negative Pitching Angle: -0.4g.
First Decoupling Speed: 1300 RPM.
Engine running speed: 3500 RPM
The transmission control unit 101 determines the First vehicle stall tendency estimation and the second vehicle stall tendency estimation. The transmission control unit 101 determine the first vehicle stall tendency estimation based on the determined effective operational parameter, the received second operational parameter and a pre-set mapping between the effective operational parameter and the second operational parameter as shown in FIG. 3a. The transmission control unit 101 determines the second vehicle stall tendency estimation based on the received second operational parameter, the third operational parameter and a pre-set mapping between the second operational parameter and the third operational parameter as shown in FIG. 3b. Let us assume that the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation falls in the moderate stall tendency zone.
First vehicle stall tendency estimation: Moderate stall tendency as per FIG. 3a
Second vehicle stall tendency estimation: Moderate stall tendency as per FIG. 3b
[0057] In moderate stall tendency, the transmission control unit have moderate amount of time to decouple the powertrain and inertia of engine will avoid engine stalling upto first decoupling speed. Then powertrain can be decoupled at the first decoupling engine speed (Th2) 1300 rpm. If the vehicle decelerated from 3500 rpm then engine braking was used from 3500 – 1300 rpm.
WORKING EXAMPLE 3
[0058] To begin with, the transmission control unit 101 receives a first operational parameter, a second operational parameter and a third operational parameter from the electronic stability programming controller 103 and determines an effective operational parameter based on the received first operational parameter. Let us consider that the operational parameters are:
Change in Front & Rear wheel Deceleration: 5m/s2(change in front wheel deceleration and rear wheel deceleration).
Master Cylinder Pressure: 150 bar.
Vehicle negative Pitching Angle: -0.3g.
First Decoupling Speed: 2000 RPM.
Engine running speed: 3500 RPM
The transmission control unit 101 determines the First vehicle stall tendency estimation and the second vehicle stall tendency estimation. The transmission control unit 101 determine the first vehicle stall tendency estimation based on the determined effective operational parameter, the received second operational parameter and a pre-set mapping between the effective operational parameter and the second operational parameter as shown in FIG. 3a. The transmission control unit 101 determines the second vehicle stall tendency estimation based on the received second operational parameter, the third operational parameter and a pre-set mapping between the second operational parameter and the third operational parameter as shown in FIG. 3b. Let us assume that the determined first vehicle stall tendency estimation and the second vehicle stall tendency estimation falls in the high stall tendency zone.
First vehicle stall tendency estimation: high stall tendency as per FIG. 3a
Second vehicle stall tendency estimation: high stall tendency as per FIG. 3b
[0059] In high stall tendency, the transmission control unit 101 has very less amount of time to decouple the powertrain and inertia of engine will avoid engine stalling upto second decoupling engine speed. Then powertrain can be decoupled at the second decoupling engine speed (Th3) 2000 rpm. If the vehicle decelerated from 3500 rpm then engine braking was used from 3500 – 2000 rpm.
ADVANTAGES
[0060] The present disclosure provides a method and a system for powertrain decoupling in automated manual transmission to prevent engine stalling. The method and the system is capable of improving engine braking assist which reduces brake wear.
[0061] The above description does not provide specific details of the manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, known, related art or later developed designs and materials should be employed. Those in the art are capable of choosing suitable manufacturing and design details.
[0062] It should be understood, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise, as apparent from the discussion herein, it is appreciated that throughout the description, discussions utilizing terms such as “receiving,” or “retrieving,” or “comparing,” or “generating,” or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.
[0063] The exemplary embodiment also relates to a system for performing the operations discussed herein. This system may be specially constructed for the required purposes, or it may comprise a general-purpose computer selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a computer-readable storage medium, such as, but is not limited to, any type of disk including floppy disks, optical disks, CD-ROMs, and magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, solid state drives, magnetic or optical cards, or any type of media suitable for storing electronic instructions, and each coupled to a computer system bus.
[0064] Further, the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be combined into other systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may subsequently be made by those skilled in the art without departing from the scope of the present disclosure as encompassed by the following claims.
[0065] The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.
[0066] It will be appreciated that variants of the above-disclosed and other features and functions, or alternatives thereof, may be combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.