Search Results

A methodology is presented to do accelerated vibration durability test, on Electro Dynamic Shaker (EDS) by using Power Spectral Density (PSD) profile based on typical customer usage pattern. A generalized iterative procedure is developed to optimize input excitation PSD profile on EDS for simulating the exact customer usage conditions. The procedure minimizes the error between the target channels measured on road and the response channels measured on EDS. Also, response of accelerometers and strain gauges at multiple locations on the test component are arrived at based on a single input excitation using this procedure. The same is verified experimentally as well. Different parameters like strain, acceleration, etc. are simulated simultaneously. This methodology has enabled successful simulation of road conditions in lab, thereby arriving at a correlation between rig and road. The correlation obtained is based on the simulation of the same failure mode as that of the road on the rig.

Scooters are becoming increasingly popular in India. Competition in this segment has forced the product developers to put focus on development time reduction and quality improvement. Any physical failure of critical parts in the actual customer usage conditions can delay the product launch. The present study is about simulation of failure of crankcase during field trials. This involved creation of Finite Element model, evolution of proper loading and boundary conditions which capture the failure area, development of a static and an accelerated dynamic test in laboratory to reproduce the field failure, the optimization of the crankcase design through FEM to achieve acceptable stress values at critical areas and validation of these results through newly developed laboratory tests. Simultaneously, field trials, which initially produced this failure were conducted and no failures were observed. Thus, the current study has saved time of actual field trials (3∼4 weeks) after the redesign.

Vision based systems using cameras are widely used in various industry verticals. The basic functionality of a vision system is to detect an object and then recognize it. In current automotive industry these systems are being used in applications like collision avoidance, intelligent cruise control, blind spot detection, parking assistance, identify pedestrians, etc. During driving conditions, 2 wheeler and 4 wheeler drivers are required to concentrate more on the road because of which they may tend to miss the traffic signs; more often during night times. The traffic signs can be one way, U-turn, right/left turn prohibited, bump ahead and etc. So there is a need for a system which detects, recognizes and intimates these signs to the driver. Extensive research is being carried out in the area of recognizing a traffic sign, but more focused research is done for a complex problem of detecting the sign in the real world environment.

This paper deals with in-cylinder flow field analysis in a motored two-stroke engine by CFD technique using STAR-CD. The main aim of this study is to find out the best turbulence model which predicts the fluid flow field inside the cylinder of a two-stroke engine. In this study, a single-cylinder, two-stroke engine which is very commonly used for two-wheeler application in India is considered. Entire analysis is done at an engine speed of 1500 rev/min. under motoring conditions. Here, three commonly used turbulence models viz. standard k-ε, Chen k-ε and RNG k-ε are considered. In addition, experiments were also conducted on the above engine at the motoring conditions to measure velocity vectors of in-cylinder flow fields using particle image velocimetry (PIV). The results of PIV were also used for validating the CFD predictions.

Two wheelers are very popular as means of transportation in ASIA. It is also used as load carrier in some places. Chassis frame is a very critical part of a two wheeler taking most of the loads coming from the roads. During the design and development stage, structural integrity of the frame needs to be established. Bump test is one of the critical life tests performed on the vehicle for evaluating the fatigue life of the frame. Normally, three to four iterations take place before frame passes this bump test. This is a time taking test process (1week per iteration) and does not guarantee the end result. In the new approach, the bump test simulation is made using ADAMS software. The ADAMS model is validated by using the axle accelerations measured in the physical bump test. Subsequently, the loads obtained from ADAMS model are used in FEM software and the stresses are predicted. The stress pattern helped in identifying the critical areas.

In recent past, the two stroke vehicle manufacturers are continuously motivated to develop extreme low emission vehicle for meeting the requirements of emissions regulations. To achieve this emission compliance, manufacturers have developed engines with better induction system, improved ignition timings, increased compression ratio (C.R) and larger after-treatment devices. As an effect of above changes, engine operating temperatures are quite high which reduces the block-piston life. Even though, typical two stroke engines are forced cooled engines, there is a lot of potential for optimizing block cooling to reduce maximum liner temperature and block gradient for enhancing block-piston durability. This paper presents an experimental study of various measures to reduce liner temperature for a two stroke, single cylinder 70 c.c. engine used for two wheeler application.

This project is an experimental investigation and optimization of piston slap noise in small two-stroke gasoline engine. Piston slap is one of the most significant mechanical noise sources in an internal combustion engine. It is a dynamic impact phenomenon between the piston and the cylinder block caused by changes in the lateral forces acting on the piston. The change in cylinder block vibration level caused by the piston impact is considered as a measure of piston slap during this experiment. The intensity of piston slap is measured in terms of vibration level in ‘g’ units, by means of accelerometers mounted on the cylinder block with Top Dead Center (TDC) and Bottom Dead Center (BDC) marker. For the design of low noise engines, all the major parameters, which contribute to piston slap, are listed and the critical four are examined through additional experiments.

This paper discusses the development of a control strategy, for a CVT that operates in combination with a mechanically throttle controlled engine, for optimal performance of the powertrain in terms of fuel economy, emissions and driveability. A concept design of an electronically controlled CVT for a quadricycle application is conceived. A lumped mass simulation model of the concept vehicle along with the powertrain was created in MATLab/Simulink. An optimal control strategy is developed and implemented in the simulation model to predict the performance and compare with that of the manual transmission.

Tyres are the primary contact between the vehicle and the road. It serves as the medium of communication between the road and the rider, which it does in terms of road loads and displacements. Therefore, measurement of dynamic wheel forces experienced by a two-wheeler is crucial for tuning the ride and handling characteristics of the vehicle. Currently, there are standard wheel force transducers available in the market, which are extensively used in cars. However, mass of such a system is relatively high to be used on two-wheelers. Special wheels and adaptors increase the unsprung mass considerably, which changes the dynamics of the vehicle. Moreover, cost of such systems is exorbitantly high to be used for two-wheelers. This paper describes the development of an innovative and a highly versatile and low-cost alternative method for real-time measurement of dynamic wheel loads and moments of a two-wheeler when compared with the currently available systems in the market.

A methodology is presented to obtain loads coming on the handle bar of a motorcycle of one model and calculating generic loads from the same for all other motorcycle models. The handle bar of a motorcycle of model M1 was instrumented with strain gages and calibrated for vertical and horizontal loads. The instrumented handle bar was assembled on the vehicle and data was collected on the test rig in laboratory. The vertical and horizontal loads acting on the handle bar, on test rig was obtained based on the calibration performed. The loads thus obtained are for a particular motorcycle model M1 and is dependent on the wheel loads of that motorcycle. These loads were converted into generic load cases, which are applicable for all models of motorcycles. The generalized loads thus generated were used in predicting the fatigue life of handle bar of a different motorcycle model (M2) using FE analysis and MSC fatigue.

This paper aims at the estimation of dynamic wheel loads of a two-wheeler through mathematical modeling that will aid during the initial stages of product development. A half car model that represents a two-wheeler was used for this purpose. Road displacements were given as input to the model and the wheel loads estimated. Actual road data obtained from two-poster rig was used as input to the model thereby making it possible to calculate the wheel loads for different customer usage conditions on different roads. In this paper, a severe rough road was chosen for verification of the model with that of the rig as the rider dynamics on such roads are the most difficult to simulate even on the rigs. The estimated values from model were verified with those measured using a two-poster rig for the same road displacement. Attempt has been further made to establish a correlation between the ride comfort predictions from the model and the two-poster rig.

This work shows numerous experimental and simulation results regarding the stability of a three-wheeled vehicle. Some vibration modes concerning three-wheeled vehicles can become unstable for a given vehicle speed. In particular, the wobble mode involves mostly the front frame while the weave mode involves mostly roll and yaw oscillations of the rear frame. This paper mainly focuses on the wobble mode, which was identified as the most influential vibration mode impacting vehicle handling, through experiments on the road using the three-wheeled passenger vehicle. A large number of parameters such as caster trail, steering damping coefficient, front frame inertia about steering axis, front tire characteristics and chassis stiffness influence the wobble vibration mode. This work mainly focused on steering damping coefficient and caster trail, and its effect on wobbling stability.

The knock sensor is provided on an engine cylinder block to detect abnormal engine combustion (knocking) and to provide feedback to engine control unit (ECU). The ECU then modifies the engine input and avoids knocking. A commonly used knock sensor is an accelerometer that detects cylinder wall vibration and estimates knocking of the engine. Selecting the location of a knock sensor in many cases involves a challenging trial and error approach that depends upon the measurement of the knock signal at many locations on engine structure. However, a cylinder block exhibits many structural resonances. Thus, a large vibration signal at the surface of cylinder block can be either due to knocking of the engine or due to the resonances of the cylinder block structure because of normal excitation forces. Hence, this conventional method does not always yield reliable results.

In recent times gearless scooters are becoming popular means of transport in ASIA because of their ease of handling in crowded traffic and superior comfort over motorcycles. Major difference, which is contributing for least vibrations incase of scooters is mechanism of engine mounting on the frame. In most of the cases motorcycle engines are rigidly fixed to the frame where as in case of scooters engine will be swinging with respect to frame. It is easy to design muffler mounting for fixed engines. Since there is no relative motion between engine and frame for motorcycle both can be fixed to frame. Swinging scooter engine demands muffler mounting directly on engine. These direct mounts may include bosses, brackets, and bolts. While useful for their intended purpose, it is possible that vibrational energy can pass between the exhaust components and the engine through this direct mounting.

In order to improve the performance and fuel economy of a reciprocating engine, it is important to reduce the overall engine frictional losses. In this paper, author conducts an experimental study on the friction characteristics due to pumping loss, valve-train system, piston assembly, auxiliaries and transmission for a 110cc, single cylinder 4-stroke gasoline engine using frictional strip-down analysis. Friction strip-down method is commonly used to investigate the frictional contribution of various engine elements at high speeds and for better understanding of the make-up of the total engine friction. The engine friction measurements for the particular engine are carried out on a motoring test rig at different engine speeds. In addition, the effect of engine operating parameters such as oil temperature and oil quantity in engine sump is also presented in detail.

Heat flux measurements can provide much needed insight into the energy flow inside an IC engine, which is the key to optimizing its performance. This paper focuses on understanding the nature of heat flux curve and how it varies with varying load conditions, engine speed, Air fuel ratio and ignition timing in a single cylinder, 4 stroke, carbureted, air cooled, spark ignition engine for motorcycle application. In-cylinder heat flux was monitored along with wall temperature and cylinder pressure for motored operation as well as fired conditions. The difference between the motoring mode and fired mode was analyzed to separate out the effects of combustion. In general, the magnitude of maximum heat flux was found to increase with engine rpm and load when all other engine parameters remained constant. The heat flux was found to increase when a mixture setting closer to the stoichiometric value was used.

Automotives are provided with a lot of intelligence that monitors, controls, actuates, and diagnose the various aspects of vehicle functionalities. One of the critical parameters required to monitor is Vehicle fuel level. Fuel level in the vehicle is a key input for engine performance, drivability, and fuel level indication in Instrumentation cluster for customer. Most economic and reliable fuel level sensor is resistive sensor with float. The purpose of this paper is to address the wrong fuel level indication in Vehicle level. Wrong fuel level indication may be due to malfunction of Instrumentation cluster signal input or Fuel level sensor function. To verify this, Instrumentation cluster is tested with HIL system instead of real time Fuel level sensor. By configuring the HIL module to analogue resistance channel, cluster is tested for fuel level bar indication. Fuel level sensor is tested by Vehicle level fuel calibration and exact issue is simulated.

Automobiles are incorporated with advanced technologies to improve riding experience, safety, and vehicle management. Considering riding experience, major concern prevails in starting and charging system. For quick start and stop, implemented Integrated Starter Generator (ISG) in two wheelers. The ISG system consists of an ISG machine and ISG controller. ISG machine acts as motor during cranking and generator during charging, controlled by ISG controller. Automation kit is made with the help of real sensors, actuators, and microcontroller to monitor and log the performance characteristics of ISG system during te sting in rig level. Sensors continuously monitor the performance parameters and once the parameters are not meeting the specification, actuators stop the testing and raise the indication. All tested data are stored in cloud and taken for analysis. This automation kit served two purposes. One is eliminated test running on the failure sample for full long testing duration.

The evaluations of ride comfort in gear shifting have been known as one of the dominant factors for vehicle quality assessment. However, those factors have not been assessed and analyzed objectively in-depth in conjunction and integration with general ride and handling parameters. In recent, the criteria set by customer have changed on account of heightened expectations, resulting in a growing demand for enhanced ride comfort. the quality of gear shifting experienced by a customer is evaluated subjectively on road leads to difficulty in arriving inferences and taking decisions due to variation in responses of people on the same situation. This study is involved the process of conversion from subjective to objective assessment on gear shifting quality by identifying the objective parameters for contributing the quality of gear shifting feel.