Sandooja A.,Mahindra Engineering Services Ltd |
Kunal R.,Mahindra and Mahindra Ltd
SAE Technical Papers | Year: 2011
In automotive Transmission especially in Manual shift Transmission, a mechanism is provided for smooth and quick shifting of gears known as Synchronizer. A synchronizer mechanism having a Sliding shift sleeve, synchronizer ring, clutch body and clutch body ring as the main components to shift the gears smoothly. A synchronizer ring and Clutch body ring having outer tooth with inclined faces i.e. chamfer on their end facing towards gear shift sleeve, having inclination faces to mesh with the same inclined faces of blocker ring and clutch body ring for smooth shifting with less effort. Generally in cold environment certain forces are acting inside the Transmission to reduce the speed of rotating elements, these force are called drag forces. Mostly these drag force are generated due to high viscosity of transmission oil and large Inertia of masses of rotating elements, bearings and oil seals friction etc. When the rotational speed of gearwheel and the shift sleeve becomes zero after synchronization, and sleeve starts to travel towards the clutch body ring via Blocker ring then these drag forces further reduce the speed of gearwheel and hence arise of scraping Noise known as "Cold Clash or Cold scratch". This paper presents the method to avoid the Scraping Noise and smoothen the shifting of Gear. To reduce this cold clash the inclination or chamfer on the end faces of Sleeve tooth and Clutch Body ring tooth are so designed asymmetrically in such a manner that the check faces 30 leading in the sense of direction of rotation 25 have a greater axial displacement than the check faces 31 trailing in the sense of direction of rotation as shown in Figure-1. This ensures that sliding sleeve exerts the pressure on the blocker ring even after achieving the synchronous speed, to allow the gearwheel to rotate with synchronous speed against existence of drag or high braking forces acting on transmission, particular due to high viscosity of cold transmission oil which affects the synchronizer performance. Copyright © 2011 SAE International.
Chikurde R.C.,Mahindra Engineering Services Ltd. |
Kumar M.,Mahindra Engineering Services Ltd. |
Singh T.,Mahindra Engineering Services Ltd.
SAE Technical Papers | Year: 2013
This paper attempts to investigate effect of integrating new petrol engine in an existing compact car engine bay on tailpipe noise. Due to lower noise emission expectations nowadays, it was necessary to analyze the new routing of exhaust system from flow and noise point of view. It was proposed to test benchmark vehicle for back pressure and Sound Pressure Levels (SPL) according to standard test procedures to set targets for these two parameters. The new exhaust system was developed based on packaging and structural constraints in engine bay and underbody and subsequent CFD and acoustic models were analyzed using 3D CFD and 1D acoustic simulation. Commercially available software like Fluent and GT-Power were used along with DOE studies for optimizing the design. 3D CFD was used for predicting pressure drop for various concepts. The design was matured based on packaging, manufacturing constraints and initial pressure drop (or back pressure). 1D CFD code was then used for predicting system level pressure drop and SPL. Use of Design of Experiment (DOE) technique was proved to be very useful to achieve target SPL and back pressure levels. Finally exhaust system was recommended based on above optimization study and tested on engineering prototype. Thus the numerical model was validated and observed to be in good agreement with test data. The recommended design was found to be satisfactory in terms of set targets. Copyright © 2013 SAE International and Copyright © 2013 SIAT, India.
Palkar A.N.,Mahindra Engineering Services Ltd.
SAE Technical Papers | Year: 2013
Transport plays major a role in the economic growth of the Nation and social welfare of the community. Wrong practices followed by Transport Operators result in environmental degradation and damage to Transport Infrastructure. To improve productivity and Safety of commercial transport sector in India, it is necessary for all transportation users to calculate, analyze and control the internal and external expenses. Dynamic weight of the moving truck is one of the methods which help to improve environmental quality, increase life of roads and bridges, increase life of the vehicle, enhance productivity and ensures high amount of safety. This paper describes System involving sensing techniques, design and integration, operational and feasibility analysis towards making it affordable, accurate and adaptable. This includes a proposal for regulatory bodies to respond to the challenge of implementation of rules for the productivity and safety of commercial road transport. Copyright © 2013 SAE International and Copyright © 2013 SIAT, India.
Dhole A.,Mahindra and Mahindra Ltd. |
Raval C.,Mahindra and Mahindra Ltd. |
Shrivastava R.,Mahindra Engineering Services Ltd.
SAE Technical Papers | Year: 2015
In commercial vehicles which generally have large capacity fuel tank, sloshing of fuel and its effect on the tank structure is very important aspect during fuel tank design. Dynamic pressures exerted by the fuel on baffles, end plates and tank shell during sloshing can lead to structural failures and fuel leakage problems. Fluid structure interaction simulation of automotive fuel tank sloshing and its correlation with physical test is demonstrated in this study. During physical sloshing test of 350 L fuel tank, cracks were observed on center baffle and spot weld failures developed on fuel tank shell. Same sloshing test was simulated for one sloshing cycle using fluid structure interaction approach in LS Dyna explicit FE solver. Water was used instead of fuel. Mesh free Smoothed Particle Hydrodynamics (SPH) method is used to represent water as it requires less computational time as compared to Eulerian or ALE method. Equation of State (EOS) was defined in LS Dyna using variable parameters of volumetric strain (EV1, EV2.etc) and constants (C1, C2.etc) in order to represent the nonlinear behavior of water accurately during sloshing event. High strain areas on baffle and end plates were studied. Locations of weld failures and cracks observed on the center baffle & shell during physical test correlated quite well with simulation results. Post correlation, fuel tank with modified baffle design was re-simulated and found to have improved performance in terms of reduced strain values. Same modified fuel tank design tested physically for target number of durability cycles in the lab and found to be meeting the requirements. This improved and proven CAE methodology thus became very important and reliable step in design and development of high capacity fuel tanks. Copyright © 2015 SAE International and Copyright © SAEINDIA.
Purohit M.,Mahindra Engineering Services Ltd. |
Marathe R.,Mahindra Engineering Services Ltd. |
Bamane S.,Mahindra Engineering Services Ltd. |
Nidgalkar D.,Mahindra Engineering Services Ltd.
SAE Technical Papers | Year: 2011
Tubular components are widely used in automotive axles and transmissions due to inherent advantage of quick development of these parts, consistency in production quality and low costs due to standardized process. The design and development of these tubular parts though underlines high investment in drawing dies. Any modification in these parts due to manufacturing constraints or some failures related to unexpected loadings are expensive and time consuming. Change in thickness may be required at only a particular location to take care of higher stresses, however, it cannot be provided considering limitation on manufacturing process. Thus, designing thickness accurately for these parts is a very important aspect of the design process. This paper demonstrates the use of FE Simulation for tubular rear axle to include the pre-stress effects of manufacturing process on the part during initial design phase. Simulation is carried out in 3-stages. First stage of the analysis is a forming simulation, followed by machining, shrink fit and service load simulation in second stage. The third stage is for fatigue simulation. Simulation results are validated by comparing dimensions of the physical parts with the dimensions obtained through forming simulation. Also, force required for forming operation is compared. The methodology can be extended to other similar tubular parts like automotive sway bars, exhaust pipes, hollow drive shaft, stay rods, etc. ABAQUS FE solver is used for first two stages of simulation and FEMFAT is used to calculate fatigue life in third stage. This method has a potential of reducing development efforts & time, significantly. Copyright © 2011 SAE International.