DESC:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
METHOD AND SYSTEM FOR PERFORMANCE IMPROVEMENT OF HYDRAULIC TORQUE CONVERTER FOR VEHICLE

Applicant:
BEML Limited
A company Incorporated in India under the Companies Act, 1956
Having address:
BEML Soudha, 23/1, 4th Main,
Sampangirama Nagar, Bengaluru - 560 027,
Karnataka, India

The following specification particularly describes the invention and the manner in which it is to be performed.

CROSS-REFERENCE TO RELATED APPLICATION AND PRIORITY
[001] The present application claims priority from Indian Patent application no. (202041001541) filed on 13th January, 2020.

TECHNICAL FIELD
[002] The present disclosure in general relates to the field of hydraulic torque converter. More particularly, the present subject matter relates to a method and an improvement in hydraulic torque converter system for performance improvement of vehicle.

BACKGROUND
[003] Hydraulic torque converter is a key interface component of a vehicle automatic transmission system. The primary function of hydraulic torque converter is torque multiplication. The hydraulic torque converter multiples the torque based on load demand by the vehicle. Generally, torque converter transfers power, changes torque through the conversation of mechanical energy between hydraulic energy and can make vehicle start and change gear smoothly. The torque converter prevents torsional vibration from engine to power train and vice versa.
[004] Generally, the flow field in a hydraulic torque converter is three dimensional, viscous and unsteady. Blade configuration, guide length of blades and flow path area arrived by using conventional design methods and theories, but it can only test, analyze or predict the flow field of some region in some conditions with more iteration which is more time consuming process and also not able to predict accurately.

OBJECT OF THE INVENTION
[005] It is an object of the present invention to method of developing an improved hydraulic torque converter system for performance improvement of vehicle.
[006] Another objective of the invention is to design hydraulic torque converter with optimum blade angle, blade radius, guide length of blade and gap optimization between the torque converter elements.
[007] Another objective of the invention is to introduce computational fluid dynamics analysis method for performance characteristics improvements of hydraulic torque converter.
[008] Yet another objective of the invention is to finalize flow path area with superior performance characteristics like torque ratio (Tr), K-factor and efficiency (?) as per design requirement.
[009] Yet another objective of the invention is to formulate systematic hydraulic torque converter load testing method for performance characteristics evaluation.

SUMMARY
[0010] Before the present improved hydraulic torque converter is described, it is to be understood that this application is not limited to the system(s), and methodologies described, as there can be multiple possible embodiments, which are not expressly illustrated in the present disclosures. It is also to be understood that the terminology used in the description is for the purpose of describing the particular implementations or versions or embodiments only and is not intended to limit the scope of the present application. This summary is provided to introduce aspects related to an improved hydraulic torque converter for performance improvement of vehicle. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.
[0011] In one implementation, an improved hydraulic torque converter is described. In one aspect, it includes hydraulic torque converter analysis and vehicle performance analysis. Further, by simulating the hydraulic torque converter in CFD analysis by eliminating cavitation improved blade angle, radius and length are obtained. Blade verification by 3D scanning is introduced to ensure blade profile accuracy. Additionally, load testing method is introduced for performance characteristics evaluation of torque converter parameters.

BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The foregoing summary, as well as the following detailed description of embodiments, is better understood when read in conjunction with the appended drawing. For the purpose of illustrating the disclosure, there is shown in the present document example constructions of the disclosure, however, the disclosure is not limited to the specific methods and apparatus disclosed in the document and the figures.
[0013] The detailed description is described with reference to the accompanying figure. In the figure, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawing to refer like features and components of the present subject matter.
[0014] Figure 1 illustrates the simplified vehicle power train flow arrangements with hydraulic torque converter.
[0015] Figure 2 illustrates the stages involved in method of hydraulic torque converter, in accordance with the present invention.
[0016] Figure 3 illustrates a flow chart of torque converter performance analysis involved in the present invention.
[0017] Figure 4 (A) and Figure 4 (B) illustrates the crucial variable parameters for round and squash type torque converter respectively used for torque converter performance analysis.
[0018] Figures 5 and 6 Illustrates the angle measurement technique used for torque converter performance analysis.
[0019] Figure 7 is a flow chart of vehicle performance analysis involved in the present invention.
[0020] Figure 8 illustrates the CFD analysis for torque converter performance characteristics improvements.
[0021] Figure 9 illustrates systematic volume mesh generation process in the present invention.
[0022] Figure 10 & 11 Illustrates the intricate blade profile verification technique, in accordance with the present invention.
[0023] Figure 12 illustrates systematic hydraulic torque converter load testing method for performance characteristics evaluation, in accordance with the present invention.
[0024] The figure depicts various embodiments of the present disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following discussion 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
[0025] Some embodiments of this disclosure, illustrating all its features, may now be discussed in detail. The words "comprising," "having," "containing," and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Although any assembly and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary, assembly and methods are now described. The disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms. Various modifications to the embodiment may be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art may readily recognize that the present disclosure is not intended to be limited to the embodiments described but is to be accorded the widest scope consistent with the principles and features described herein.
[0026] Various modification to the embodiment may be readily apparent to those skilled in the art, and the generic principles herein may be applied to other embodiment related to method of designing hydraulic torque converter. However, one of ordinary skill in the art may readily recognize that the present disclosure relating to method of designing hydraulic torque converter is not intended to be limited to the embodiments described, but is to be accorded the broadest scope consistent with the principles and features described herein.
[0027] As used in the present invention, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicate otherwise.
Torque ratio (Tr)- Refers to the ratio between turbine torque to impeller torque.
Speed Ratio (Sr) - Refers to the ratio between turbine speed to impeller speed.
Efficiency (? ) - Refers to the product of torque ratio and speed ratio.
K-factor - Refers to the absorption characteristics of torque converter in-terms of impeller torque capacity.
[0028] The present subject matter relates to a method for designing an improved hydraulic torque converter for performance improvement of vehicle. The first stage includes torque converter performance analysis. Further, it includes vehicle performance analysis, computational fluid flow analysis and intricate blade profile verification technique. Additionally, systematic load testing method for performance characteristics evaluation introduced for performance characteristic improvements.
[0029] The system further includes blade guide length improvement technique to increase the length of the blade considering the blade angle constraints by which improving the torque converter efficiency and reducing the leakage flow losses. Variable cross-sectional flow area is introduced in each torque converter element flow path in torque converter performance analysis. The torque converter performance analysis is carried out by calculating the performance characteristic like torque ratio, K-factor and efficiency in accurate way at different speed ratio conditions which is equivalent to systematic hydraulic torque converter load testing method results.
[0030] Further by simulating in CFD analysis by varying the speed ratio from 0 to 0.90 by which individual element torque arrives in fully converged condition to calculate the performance characteristics like torque ratio, K-factor and efficiency. The results exactly accord with systematic hydraulic torque converter load testing method results. Further, the CFD analysis is used for internal fluid flow field verification by eliminating cavitation inside the torus portion.
[0031] During designing of the torque converter, the key variable design parameters like blade radius, blade angle, flow path area and torus shape are considered. The clearance between the blades between elements (Impeller exit to Turbine entry, Turbine exit to stator entry and stator exit to Impeller entry portion) i.e., blade gap is optimized to reduce the flow losses.
[0032] Referring now to figure 1, it illustrates the vehicle power train flow arrangements (100). The power from the engine (102) is transmitted through the hydraulic oil by torque Converter (101) to the planetary transmission unit (104), differential unit or steering & brake clutch assembly unit (105) and final drive unit (106) through wheel or crawler in agreement with change in load. The hydraulic torque converter (101) protects the planetary transmission unit (104) by absorbing rotational irregularities of the engine input. It also protects the engine (102) by absorbing abrupt variation of load.
[0033] Referring now to figure 2 (A) and figure 2 (B), it illustrates the stages involved in designing of improved hydraulic torque converter for performance improvement (200) of vehicle. As per design specification, performance characteristics like K-factor, torque ratio & efficiency arrived with the help exclusive torque converter performance analysis (210). Stall characteristics confirmed as per requirement with the help of vehicle performance analysis (220). CFD analysis (230) is used to verify the internal flow fields to avoid cavitation and to evaluate torque converter performance characteristics as per specification. Blade profile verification technique (240) is introduced to verify the contour blade profiles as per design specification. To evaluate the design accuracy, hydraulic torque converter load testing method (250) is established for performance characteristics verification. Overall time duration is optimized for development of improved hydraulic torque converter.
[0034] Referring now to figure 3, it illustrates the flow chart for torque converter performance analysis (300). By systematic analysis of variable design parameters, optimized performance characteristics like torque ratio, K-factor and efficiency are arrived as per design specification with short time span.
[0035] Referring now to figure 4 (A) and figure 4 (B), it illustrates the crucial variable parameters for round type torque converter (400 A) and squash type torque converter (400 B) used for torque converter performance analysis (300). The effective flow is at mean design path (410 A & B) used for defining the variable parameters. R1, R2 & R3 denotes impeller exit radius, impeller entry radius & turbine exit radius for round type torque converter (400 A) and squash type hydraulic torque converter(400 B) which is measured from mean design path (410 A & B). In present invention, the gap between each impeller to turbine blade (430A), turbine to stator blade (430B) and stator to impeller (430C) is lesser than 0.01 times of overall flow area for round type hydraulic torque converter. For squash type hydraulic torque converter, the gap between impeller blade to turbine blade flow area (420A) achieved in the range of 0.13 to 0.15 times of overall flow area, further the gap between turbine blade to stator blade flow area (420B) achieved in the range of .014 to 0.016 times of overall flow area and similarly, the gap between stator blade to Impeller blade flow area (420C) achieved in the range of 0.35 to 0.37 times of overall flow area.
[0036] Figure 5 & 6 shows the blade angle measurement technique (500 and 600) for round and squash type converter which is used for torque converter performance analysis (210). Blade angles are measured from torque converter axis reference point to leading and trailing edge of the blade portion. Impeller, turbine and stator blade (510,520,530, 610, 620 & 630) constructed using camber line technique with variable blade thickness. Impeller, turbine and stator entry and exit angle denotes Q1, Q2, Q3, Q4, Q5 and Q6 respectively for round and squash type converter. Reference radius (R & R’) for shell and core portion used for stating the co-ordinate data.
[0037] Referring now to figure 7, it illustrates the flow chart for vehicle performance analysis (700). By systematic analysis of variable design parameters, optimized vehicle performance achieved as per design specification with short time span.
[0038] Figure 8 illustrates the CFD analysis flowchart (750) for performance characteristics improvements. The entire fluid flow model region considered, and the coupling of the mesh block is applied by using arbitrary interface technique in CFD simulation using to each boundary of elements. Surface and volume mesh ensured with mesh quality confirmation like pierced surface, poor quality face, close proximity face, non-manifold edge and non-manifold vertices. Moving reference frame technique is used to ensure the element rotation as per speed ratio (Sr) condition. Steady state and transient analysis simulated with K-? and K-? type turbulence model. Unbalanced torque cumulative value not exceeding 0.1% of impeller torque. Improved torque converter performance characteristics ensured by elimination of cavitation and flow losses.
[0039] Figure 9 shows the mesh generation method (800). The entire fluid flow model (802) and fluid flow model with region (803) is generated from main assembly model (801) and further divided in region as per torque converter elements (Impeller, Turbine & Stator). In-place interface method is introduced between each region. Further overall surface mesh (804) and overall volume mesh (805) is generated combined with quality verification.
[0040] Figure 10 & 11 illustrates the intricate blade profile verification technique. 3D scanning method used to convert the actual casting blade profiles by cloud point data (902) to neutral file format. Blade profile acceptable limits are ensured by superimposed 3D scanned cloud point data with master blade component (901) profiles. If any blade profile deviation persists beyond acceptable range, systematic core box / pattern improvement is introduced to ensure blade profile accuracy for improving the performance characteristics.
[0041] Figure 12 illustrates the systematic hydraulic torque converter load testing method (950) for performance characteristics evaluation. Thyristor drive variable speed DC motor (955) is used as a prime mover to give power to hydraulic torque converter (101). Water dynamometer (960) connected with hydraulic torque converter (101) as a loading member. External hydraulic power pack (975) used for circulating the hydraulic oil from sump (980). To maintain Internal fluid pressure, relief valve (970) and regulator valve (965) provided. hydraulic torque converter (101) outlet oil flow is transit thru’ the oil cooler (985) to sump (980). Input speed sensor and torque transducer (985) installed to capture the input speed and torque. Similarly output speed and torque monitored by data capturing unit (990). Torque converter performance characteristics like K-factor, Torque ratio and efficiency arrived by using actual measured data. K-factor is the ratio between impeller speed (Ni) to square root of impeller torque (Ti). Torque ratio (Tr) is the ratio between turbine torque (Tt) to impeller torque (Ti). Speed ratio (Sr) is the ratio between turbine speed (Nt) to impeller speed (Ni). Torque converter efficiency is the product of speed ratio (Sr) and torque ratio (Tr).
[0042] Further, the invention can be used, but not limited to, in the following applications.
[0043] One embodiment of the invention describes a method of hydraulic torque converter.
[0044] Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include those provided by the following features.
[0045] Some object of the invention is to develop a method for designing hydraulic torque converter for performance improvement of vehicle.
[0046] Some objective of the invention is to finalize variable parameters like blade radius, blade angle and flow area with superior performance characteristics like torque ratio, K-factor and efficiency as per design requirement.
[0047] REFERRAL NUMERALS:

Element Description Reference Numeral
Vehicle power train 100
Conventional hydraulic torque Converter 101
Engine 102
Planetary transmission unit 104
Differential unit 105
Final drive unit 106
Design method of improved hydraulic torque converter for performance improvement 200
Torque converter performance analysis 210
Vehicle performance analysis 220
CFD analysis 230
Blade profile verification technique 240
Hydraulic torque converter load testing method 250
torque converter performance analysis flowchart 300
Round type torque converter 400 (A)
Squash type torque converter 400 (B)
mean design path (Round type) 410 (A)
mean design path (Squash type) 410 (B)
gap between each Impeller blade to turbine blade for squash type 420 (A)
gap between each turbine blade to stator blade for squash type 420 (B)
gap between each stator blade to Impeller blade for squash type 420 (C)
gap between each impeller to turbine blade for round type 430 (A)
gap between each Turbine to Stator blade for round type 430 (B)
gap between each Stator to impeller for round type 430 (C)
Impeller blade 510
Turbine blade 520
Stator blade 530
Blade angle measurement technique 500 and 600
CFD analysis flowchart 750
mesh generation method 800
Assembly model 801
Fluid flow model 802
Fluid flow model with region 803
Overall volume mesh 804
Overall surface mesh 805
Master component 901
Cloud point data 902
Impeller blade verification 903
Turbine blade verification 904
Stator blade verification 905
Hydraulic torque converter load testing method 950
Variable speed DC motor 955
Water dynamometer 960
Regulator valve 965
Relief valve 970
External hydraulic power pack 975
Hydraulic oil from sump 980
Speed sensor and torque transducer 985
Data capturing unit 990

,CLAIMS:
1. A method for optimizing the performance of hydraulic torque converter (200) comprising the steps of -
torque converter performance analysis (210);
vehicle performance analysis (220);
computational fluid flow analysis (230);
intricate blade profile verification technique (240); and
systematic load testing for performance characteristics evaluation (250).

2. The method for optimizing the performance of hydraulic torque converter (200) as claimed in claim 1, wherein the torque converter performance analysis (210) is configured with blade guide length optimization technique to improve the torque converter efficiency and reduce the leakage flow losses by increasing the length of the blade considering the blade angle constraints.

3. The method for optimizing the performance of hydraulic torque converter (200) as claimed in claim 1, wherein the torque converter performance analysis (210) is configured by optimizing the variable cross-sectional flow area in each torque converter element flow path.

4. The method for optimizing the performance of hydraulic torque converter (200) as claimed in claim 1, wherein the torque converter performance analysis (210) is configured by optimizing the performance characteristic like torque ratio, K-factor and efficiency at different speed ratio conditions equivalent to systematic hydraulic torque converter load testing method (950).

5. The method for optimizing the performance of hydraulic torque converter (200) as claimed in claim 1, wherein the vehicle performance analysis (220) configured with optimizing the torque ratio, K-factor and efficiency by simulating in CFD analysis tool by varying the speed ratio from 0 to 0.90 for achieving the individual element torque in fully converged condition, in consistence with the results of systematic hydraulic torque converter load testing method (950).

6. The method for optimizing the performance of hydraulic torque converter (200) as claimed in claim 5, wherein the CFD analysis (230) is configured for internal fluid flow field verification by eliminating cavitation inside the torus portion to evaluate torque converter performance characteristics as per specification.

7. The method for optimizing the performance of hydraulic torque converter (200) as claimed in claim 1, wherein the blade profile verification technique (240) is configured to verify the contour blade profiles as per design specification.

8. The method for optimizing the performance of hydraulic torque converter (200) as claimed in claim 1, wherein the hydraulic torque converter load testing method (250) is configured for performance characteristics verification to optimized the overall time duration for development of improved hydraulic torque converter.

9. The method for optimizing the performance of hydraulic torque converter (200) as claimed in claim 1, wherein the hydraulic torque converter (200) are round type torque converter (400 A) and squash type torque converter (400 B) used for torque converter performance analysis (300).

10. The method for optimizing the performance of hydraulic torque converter (200) as claimed in claim 1, wherein the round and squash type hydraulic torque converter are configured with R1, R2 & R3 denotes impeller exit radius, Impeller entry radius & Turbine exit radius for effective flow at mean design path (410 A & B) for defining the variable parameters.

11. The method for optimizing the performance of hydraulic torque converter (200) as claimed in claim 10, wherein the round type hydraulic torque converter is configured with a gap lesser than 0.01 times of overall flow area, between each impeller to turbine blade (430A), Turbine to Stator blade (430B) and Stator to impeller (430C).

12. The method for optimizing the performance of hydraulic torque converter (200) as claimed in claim 1, wherein for the squash type hydraulic torque converter, the gap between Impeller blade (510) to turbine blade (520) flow area (420A) is configured to be in the range of 0.13 to 0.15 times of overall flow area, the gap between turbine blade (520) to stator blade (530) flow area (420B) is configured to be in the range of .014 to 0.016 times of overall flow area and the gap between stator blade (530) to Impeller blade (510) flow area (420C) is configured to be in the range of 0.35 to 0.37 times of overall flow area.

13. The method for optimizing the performance of hydraulic torque converter (200) as claimed in claim 1, wherein the round and squash type converter are configured with the blade angle measurement (500 and 600) for torque converter performance analysis (210) by measuring the blade angle from torque converter axis reference point to leading and trailing edge of the blade portion.

14. The method for optimizing the performance of hydraulic torque converter (200) as claimed in claim 1, wherein the unbalanced torque cumulative value is configured to be less than equal to 0.1% of impeller torque.

15. The system for optimizing the performance of hydraulic torque converter (200) comprising
at least one systematic hydraulic torque converter load testing (950) setup for performance characteristics evaluation;
a thiristor drive variable speed DC motor (955) configured to be a prime mover to give power to hydraulic torque converter (101);
a water dynamometer (960) configured to be connected with hydraulic torque converter (101) as a loading member;
a external hydraulic power pack (975) for circulating the hydraulic oil from sump (980);
at least one relief valve (970) and a regulator valve (965) are provided to maintain internal fluid pressure;
an input speed sensor and torque transducer (985) are configured to be installed to capture the input speed and torque;
a data capturing unit (990) for monitoring output speed and torque; and
a hydraulic torque converter unit (101) outlet oil flow is configured to transit through the oil cooler (985) to sump (980).