Mohan B.,TVS Motor Company |
Karanam V.M.,TVS Motor Company |
Padmanabhan C.,Indian Institute of Technology Madras
SAE Technical Papers | Year: 2015
The aim of the present study is to develop feasible test methods to measure tire parameters that can be used in two wheeler industry for tire development. In this work, test methods are developed to measure the longitudinal friction coefficient and stiffness characteristics of motorcycle tires. Using the measured longitudinal forces from the testing procedure, a fairly accurate tire model has been developed. Based on this tire model the braking performance of the motorcycle is estimated using an analytical model of the vehicle. These are validated with experimental data. It is found that there is a good match between the results. The test is conducted for various bias ply tires used in motorcycles and the results are presented. The test methods proposed are shown to be adequate to estimate tire characteristics that are important for tire development and is less expensive compared to the standard testing facilities available. The present study although carried out using a two wheeler, can be applied to tires in other vehicles also. Copyright © 2015 SAE Japan and Copyright © 2015 SAE International.
Rajagopal Jeyapaal B.,TVS Motor Company |
Krishna V.,TVS Motor Company |
Marudachalam K.,TVS Motor Company
SAE Technical Papers | Year: 2016
Vibrations have become an increasingly important attribute for determining the quality of automotive products. Particularly, this becomes more acute in the case of tactile vibrations of powered two-wheelers - motorcycles and scooters. This paper deals with vibrations of a scooter vehicle. Scooters are normally a two-wheeler with a four stroke single cylinder spark ignited engine. Vibrations of a scooter are mainly caused by the inertial imbalance forces of the engine, combustion forces and road undulations. Vibrations due to road undulations are mostly reduced by toggle link mechanism, resilient mounts of the engine and the shock absorbing suspension of the frame. The power train assembly is designed in such a way that the inertial imbalance forces in the power train assembly are distributed at a required angle called the ellipse angle. This configuration ensures that the engine forces which are spread unequally in different directions are made to align and contribute only to the vertical and pitch modes of the engine. In spite of the achieving the above mentioned configuration, there are vibrations due to force transfer through the toggle link mechanism to the vehicle frame. This paper explains ways of reducing of tactile vibration of a scooter by addressing these issues by using the theory of center of percussion. It also explains ways of determining the optimum mounting position of a scooter engine based on engine layout, engine geometry, inertial balancing of engine forces, isolation and the center of percussion for reduced vibration. Theoretical analysis with calculations about the angle of engine mounting, length of the swing arm, aligning engine forces by distributing the imbalance mass are discussed. Analytical models are then validated using experiments on design optimized configuration resulting in increased vibration comfort of the vehicle. Copyright © 2016 SAE International.
Roy H.K.,University of Warwick |
Roy H.K.,TVS Motor Company |
McGordon A.,University of Warwick |
Jennings P.A.,University of Warwick
IEEE Transactions on Vehicular Technology | Year: 2014
Hybrid electric vehicles (HEVs) are considered to be one of the energy-efficient technologies for near-term sustainability of the transportation sector. Over the years, research has focused on improving fuel economy (FE) for a given drive cycle, but FE variability over a realistic range of real-world driving patterns has been generally overlooked, and this can lead to FE benefits not being fully realized in real-world usage. No systematic methodology exists to reduce FE variability by design optimization of powertrain components. This study proposes a methodology of powertrain component optimization to reduce the FE variability due to variations in driving patterns. In the proposed methodology, powertrain components are optimum over a range of driving patterns of different traffic conditions and driving styles simultaneously. The proposed methodology demonstrates the potential to reduce FE variability by up to 34% over six driving patterns of different traffic conditions and driving styles. © 2013 IEEE.
Hazra S.,TVS Motor Company |
Sensarma P.,Indian Institute of Technology Kanpur
IET Renewable Power Generation | Year: 2011
This study presents a detailed investigation on self-excitation of a squirrel-cage induction generator (SCIG) used in a wind energy conversion system. Air-gap flux of the SCIG is gradually built up through controlled current injection from a voltage source converter (VSC), connected directly across its stator terminals. Dc voltage of the VSC is ramped from a small initial value, which is the rectified output of the small terminal voltage developed because of remanent magnetism. Increase in air-gap flux increases generator terminal voltage and output power which further increases the dc bus voltage. The field-oriented control method is appropriately applied both for control of voltage build-up as well as dynamic transients. The critical factors deciding this collaborative excitation are analysed and sufficient conditions are derived analytically. System modelling and analytical results are validated through numerical simulation and verified on a 2.2kW laboratory prototype. © 2011 The Institution of Engineering and Technology.
Hazra S.,TVS Motor Company |
Sensarma P.S.,Indian Institute of Technology Kanpur
IET Renewable Power Generation | Year: 2010
This study presents a rugged and cost-effective scheme for start-up and operation of a stand-alone squirrel cage induction machine (SCIG) for a wind energy conversion system (WECS). A voltage source converter (VSC) directly interfaces the SCIG with an equivalent dc load network, which could also be the DC link of an inverter. The VSC dc bus is supported by an electrolytic capacitor and the proposed scheme ensures reliable start up with these rudimentary components. The dc bus voltage is ramped to the rated value from a small initial voltage produced by remanent magnetism of the SCIG core. Subsequently, the load is applied. The V/f control paradigm for motoring operation is suitably extended to the SCIG for controlling both voltage build-up and dynamic transients. A controller is specifically designed to maintain constant dc bus voltage under wind speed and electrical load variations. Steady-state machine flux is maintained constant up to the base speed, which maximises machine utilisation and power extraction especially at higher wind speeds. The overall system modelling and analytical control design is presented. The proposed control strategy has been validated through simulation and experimentally verified on a low power (2.2 kW) laboratory prototype. © 2010 © The Institution of Engineering and Technology.
Krishna A.S.,Indian Institute of Technology Madras |
Mallikarjuna J.M.,Indian Institute of Technology Madras |
Kumar D.,TVS Motor Company
Applied Energy | Year: 2016
This paper deals with the in-cylinder flow field analysis in a two-stroke engine under motoring conditions by particle image velocimetry (PIV) and computational fluid dynamics (CFD). The main objective is to analyze the effect of engine parameters viz., engine speed, compression ratio (CR) and port orientation on the in-cylinder flows in a loop-scavenged two-stroke gasoline direct injection (GDI) engine, with an aim to help researchers to design fuel efficient and less polluting two-stroke engines. In this study, a single-cylinder 70 cm3 two-stroke engine which is very commonly used for the two-wheeler application, is considered. The engine cylinder is modified to provide optical access into the in-cylinder region. The PIV experiments are conducted at various engine speeds viz., 500, 1000 and 1500 rev/min, and the plane averaged velocity vector fields obtained, are analyzed to understand the in-cylinder flow behavior. The CFD study is also carried out using the commercial CFD code, STARCD, to study and compare the in-cylinder flow parameters at various engine operating conditions. The CFD results are compared with the experimental results to the extent possible. The CFD predictions are found to be in good agreement with the experimental results. Therefore, the CFD analysis has been extended further to understand the effect of various engine parameters on the in-cylinder flows. We found that the turbulent kinetic energy and tumble ratio increased by about 25% and 20% respectively, when the engine speed was increased from 1000 to 1500 rev/min. Also, we found that the turbulent kinetic energy and tumble ratio decreased by about 13% and 26% when the compression ratio was increased from 7 to 8. In addition, we found that the port orientation, rather than port areas had a greater influence on the in-cylinder flow parameters. © 2016 Elsevier Ltd.
Khare S.,TVS Motor Company |
Singh O.P.,TVS Motor Company |
Bapanna Dora K.,TVS Motor Company |
Sasun C.,TVS Motor Company
Engineering Failure Analysis | Year: 2012
The customers of the vehicles reported high noise and vibration in the engine at an early stage of service lifetime. An analysis of the various components of the internal combustion engine was carried out. Subsurface cracks and pit marks were seen in the crank pin, roller bearings and big end surfaces of the connecting rod. It was found that high wear at the interface of these components was the main culprit. A laboratory test set-up was developed to correlate and reproduce the field failures. The loads and boundary conditions obtained from the experiments were used in the finite element model of the connecting rod assembly. Results shows high interfacial pressure and stresses near the junction of web and flange of the connecting rod. The modified design of the connecting rod shows significant reduction in the extreme pressure in FEM resulting in the significant enhancement of durability life in laboratory test. A discussion of the spalling problem has been provided leading to the connection of pick pressure and spalling phenomena. © 2011 Elsevier Ltd.
Vaishya A.L.,TVS Motor Company |
Phadnis S.,TVS Motor Company
SAE Technical Papers | Year: 2013
In the recent past, the non-geared (step less) transmission scooters are becoming more popular mainly due to ease of driving without gear shift hassle. Typically these scooters transmit the power through a continuously variable transmission commonly called as CVT. The CVT of a scooter is generally air cooled and located in a protective chamber. This chamber reduces the heat transfers between the CVT and the atmosphere. The temperature reached inside the chamber during the operation of the CVT is quite high, especially when the CVT is operated in hot environment. This may reduce the service life of the drive-belt since it generally decreases when the average operating temperature increases. Along with V belt, high temperature inside CVT chamber also deteriorates durability of centrifugal clutch liner, bush, centrifugal rollers and other CVT parts. Therefore, it is necessary to limit the operating temperature of the CVT system. The main objective of this research is to investigate temperature of CVT parts and optimize the air flow path and air flow rate inside CVT chamber. Tests were carried out to measure the surface temperature distribution of CVT parts and air temperature distribution inside CVT chamber under different vehicle test conditions. This study has contributed to measure the temperature and identify the main causes affecting CVT cooling. Results with improved CVT chamber cooling were also plotted. © Copyright @2013 SAE Japan and Copyright @ 2013 SAE International.
Kavekar P.C.,TVS Motor Company |
Ghodeswar D.B.,TVS Motor Company
SAE Technical Papers | Year: 2013
In order to comply with the existing emission norms of BSIII in India or EURO III and beyond that also, it is not sufficient to use the catalytic converter technology alone over the wide range of engine operating maps. Different studies across the world have proved that the cost, drivability, operating range against AFR, heat dissipation rate characteristics of catalytic converter limit their use in startup and idling conditions. One common way to tackle this condition is to use the Secondary Air Injection (SAI) system. In this system, small amount of air is injected after the exhaust port to initiate the thermal oxidation of gases. The right amount of air injected at the right time and at right location will reduce the emission by 37-90%. In the following study, SI engine vehicle with single cylinder, 160 cc and having carburetor is used as a test vehicle to evaluate the performance of SAI. The SAI system is modeled in AVL BOOST software and validated against the experimental data. The experimental data is collected at transient condition of IDC (Indian Driving Cycle). SAI system of the same vehicle is modified for different parameters like reed stopper height, SAI outlet pipe length and angle of secondary air injection. In order to avoid the complexity in experiments, DOE technique is used. The optimum parameters of SAI are determined for maximum CO conversion efficiency with uncoated CAT. The combination giving best conversion efficiency is then tested with coated CAT for emission cycle. Model results and the experimental results are compared on the basis of mass flow rate. © Copyright @2013 SAE Japan and Copyright @ 2013 SAE International.
Singh O.P.,TVS Motor Company |
Sreenivasulu T.,TVS Motor Company |
Kannan M.,TVS Motor Company
Applied Acoustics | Year: 2014
Fins as extended surfaces are attached to the internal combustion engine surfaces for enhancing the heat transfer. However, these fins vibrate at various frequencies, which produce undesirable radiated noise. To mitigate this effect, automobile industry inserts rubber dampers between these fins. These rubber dampers reduce the fins' amplitude of vibration and thus reduce the radiated noise from the fin surfaces. Investigations on the effect of rubber dampers on the engine's NVH (Noise-Vibration-Harshness) and thermal performance using numerical (FEM and CFD) and experimental measurement have been presented in this paper. Experiments were conducted in the semi-anechoic chamber on an engine with and without rubber dampers to measure the radiated noise from the fins. It was found that rubber dampers assist in reducing engine high frequency noise signals at higher engine speeds. Modal and harmonic response analysis was carried out on various designs for NVH characteristics improvement. Prototypes of the final design was made and tested for the NVH performance. Computational fluid dynamics (CFD) simulations were performed on engine with and without rubber dampers to investigate the thermal performance. It was found that rubber dampers increase engine temperature by about 10%. Effect of rubbers dampers on the cost and environmental impact has also been discussed. This paper provides a systematic procedure to investigate the effect of rubber dampers and a method to eliminate these dampers from the engines with the same NVH and better thermal performances. © 2013 Elsevier Ltd. All rights reserved.