Search Results

Particulate matter is one of the major pollutant responsible for deteriorating air quality, particularly in urban centers. Information on contributing sources with the share from different sources is a first and one of the important steps in controlling pollution. Diverse sources, anthropogenic as well as natural, like industries, transport, domestic burning, construction, wind-blown dust, road dust contribute to particulate matter pollution. Receptor modeling is a scientific method which is utilized for assessment of the contribution of various sources based on chemical characteristics of particulate matter sources and ambient air particulate matter. Representative data of fractions of various chemical species in the particulate matter from the different sources i.e. source fingerprint is an essential input for the receptor modeling approach.

Automotive manufacturers are concerned about the safety of its customers. Safety critical components like wheel hub are designed considering the severe loads generated from various customer usage patterns. Accelerated tests, which are derived from Real World Usage Patterns (RWUP), are conducted at vehicle level to ensure the wheel hub meet the durability targets. Load and strain measurement are done to understand the critical lateral loading undergone by the wheel hub. Measured data is synthesized to drive the duty cycle. Finite Element (FE) Analysis of Wheel end is performed at module level considering measured loads to capture the exact load path in physical test. Simulation results are compared with the measured strain for validating the FE analysis procedure. FE analysis was repeated for different wheel hub designs, combinations of different flange radius (R) and flange width (t), to understand the effect of the two critical dimensions on wheel hub durability.

In present scenario, tyre industry is more focused on providing maximum extent of NVH comfort to passengers by improvising the tyre design. Noise contribution from the tyres is classified in to three regions, viz., structure-borne (tyre vibrations), air-borne (tread pattern) and cavity noise (air cavity). In general, a Finite Element (FE) model of tyre provides an inherent advantage of analyzing tyre dynamic behavior. In this paper, an attempt was made to develop a three-dimensional FE tyre model and validate the same through experimental approach. The CAD Model of the tyre was generated through 3D image scanning process. Material property extraction of tyre was carried out by Universal Testing Machine (UTM) to generate Finite Element (FE) model. For validation of tyre FE model, Experimental Modal Analysis (EMA) and Noise Transfer Function (NTF) were conducted.

CNG has recently seen increased penetration within the automotive industry. Due to recent sanctions on diesel fuelled vehicles, manufactures have again shifted their attention to natural gas as a suitable alternative. Turbocharging of SI engines has seen widespread application due to its benefit in terms of engine downsizing and increasing engine performance [1]. This paper discusses the methodology involved in development of a multi cylinder turbocharged natural gas engine from an existing diesel engine. Various parameters such as valve timing, intake volume, runner length, etc. were studied using 1D simulation tool GT power and based on their results an optimized configuration was selected and a proto engine was built. Electronic throttle body was used to give better transient performance and emission control. Turbocharger selection and its location plays a critical role.

Major cause of air pollution in the world is due to burning of fossil fuels for transport application; around 23% GHG emissions are produced due to transport sector. Likewise, the major cause of air pollution in Indian cities is also due to transport sector. Marginal improvement in the fuel economy provide profound impact on surrounding air quality and lightweighting of vehicle mass is the key factor in improving fuel economy. The paper describes robust and integrated approach used for design and development of lightweight bus structures for Indian city bus applications. An attempt is made to demonstrate the use of environment friendly material like aluminium in development of lightweight superstrutured city buses for India. Exercise involved design, development and prototype manufacturing of 12m Low Entry and 12m Semi Low Floor (SLF) bus models.

Precise control over mixture formation withhigh fuel pressure and multiple injections allows Gasoline Direct Injection (GDI) engines to be operated satisfactorily at extreme conditions wherePort Fuel Injection (PFI) engines wouldnormally struggle due to combustion instability issues. Catalyst heating phase is one such important condition which is initiated after a cold engine start to improve the effectiveness of the three-way catalyst (TWC). For a given TWC specification, fast light-offof TWC is achieved in the catalyst heating phase by increasing the exhaust gas temperature with higher exhaust mass flow. The duration of this phase must be as short as possible, as it is a trade-off between achieving sufficient TWC light off performance and fuel efficiency.

Automotive manufacturers are constantly working towards enhancing the driving experience of the customers. In this context, improving the static and dynamic gear shift quality plays a major role in ensuring a pleasant and comfortable driving experience. Moreover, the gear shift quality of any manual transmission is mainly defined by the design of the synchronizer system. The synchronizer sleeve strut detent groove profile plays a vital role in defining the performance of the synchronizer system by generating the minimum required pre-synchronization force. This force is important to move the outer synchronizer ring (blocker ring) to the required index position and to wipe-out the oil from the conical friction surfaces to build rapid high cone torque. Both these functional requirements are extremely critical to have a smooth and quick synchronization of the rotating parts under dynamic shift conditions.

Continually increasing customer demands and legislative Requirements regarding fuel economy, emissions, Performance, drive ability and comfort need to be met by every OEM's developing vehicles worldwide. There is a serious pressure to reduce CO2 emission from automotive application which contributes to around 15.9% of the total CO2 production based on the Surveys done time to time. In a developing market like India, many foreign players are entering with lots of option for offering to this market. The parameters of prime importance here are fuel efficiency with good drive ability and at the same time affordable price. Diesel engines are finding these benefits and attracting the buyer over its counterpart (Gasoline). The road condition and the driving pattern in India compared with developed countries differ to a major extent. In India, the Low speed uses are predominating in Cities and in Ghats.

Reducing the vibrations in the powertrain is one of the prime necessities in today's automobiles from NVH and strength perspectives. The necessity of 4×4 powertrain is increasing for better control on normal road and off-road vehicles. This leads to bulky powertrains. The vehicle speeds are increasing, that requires engines to run at higher speeds. Also to save on material costs and improve on fuel economy there is a need for optimizing the mass of the engine/vehicle. The reduced stiffness and higher speeds lead to increased noise and vibrations. One more challenge a powertrain design engineer has to face during design of its transmission housings is the bending / torsional mode vibrations of powertrain assembly. This aggravates other concerns such as shift lever vibrations, shift lever rattle, rise in in-cab noise, generation of boom noise at certain speeds, etc. Hence, reducing vibrations becomes an important and difficult aspect in design of an automobile.

Two-stroke engine two- and three-wheelers comprise over half of the total vehicle population in South Asia and, as such, are likely to be significant contributors to particulate air pollution in large cities. Because there are no standards for particulate emissions from two-stroke engine gasoline vehicles, there is very little data available quantifying their emission levels. This study examined the procedure for measuring particulate emissions from two-stroke engines which comprise predominantly liquid droplets, and measured mass emissions from in-use three-wheelers to examine the impact of the engine condition, lubricant type and quantity, and fuel quality. The results are compared to smoke emission levels.

Sound Quality (SQ) of brake and clutch pedal assembly plays an important role in contributing to vehicle interior noise and perception of sound. Quiet operation of brake and clutch units also reflects the vehicle built and material quality. Noise emitted from these sub-assemblies has to meet certain acceptance criteria as per different OEM requirements. Not much work has been carried on this over the years to characterize and quantify the same. An attempt has been made in this paper to study the sound quality of brake and clutch pedal assemblies at component level and validate the same by identifying the parameters affecting SQ. Effect on noise at different environmental conditions was studied with typical operating cycles in a hemi-anechoic chamber. The effect of sensor switches integrated within the clutch and brake pedal on sound quality is analyzed. It is found that the operating characteristics of switches drives the noise and SQ.

Air suspension systems had been introduced in automobiles since 1950s. These systems are being explored to improve the ride comfort, handling stability and also serve as a medium for better cargo protection. These system are well developed for buses and high end passenger sedans, also have feasibility for adapting for wide range of configurations of suspension system and axle. Passenger cars and Sports Utility Vehicle (SUV) pickup category of vehicle offers different challenges such as space availability, spring selection and characterization that need to be addressed for successful implementation of air suspension in these category vehicles. This work defines methodology to implement air suspension system in SUV Pickup category vehicle. Paper work includes concept study, mathematical co-relation, and prediction of air spring characteristics and integration of experimental and analytical tool for development of air suspension system.

The automotive industry is currently facing the challenge of significantly stringent requirements regarding CO₂ emission and fuel economy coming from both legislations and customer demand. Advanced engine technologies play a vital role for downsizing of gasoline engine. The development of key design technologies for high efficiency gasoline engines is required for the improvement of competitive power in the global automobile industry. This paper focused on effect of geometry of intake manifold of gas exchange process and consequently the performance of the engine. Specially, the optimal design technologies for the intake manifold and intake port shape must be established for high performance, increasingly stringent fuel economy and emission regulations. Space in vehicle or packaging constraints and cost are also important factors while consideration of the design.

In today's fast growing automobile world, the Emission limits are stringent; customer expectations of vehicle performance and Fuel economy are more. Achieving these parameters for the given engine are challenging task for any automobile engineers. BS4 Emission limits are 50% more stringent than BS3 limits and from April 2010 onwards, all passenger cars which will be selling in 13 metro cities in India should be BS4 emission compliant. In this paper, we have described how BS4 limits were achieved in a MPV with 2.49 l, 70kW Common Rail Direct Injection Turbocharged Diesel engine, with push rod. During Emission development, the following processes were followed to meet BS4 emission limits without sacrificing the engine performance, Fuel Economy and Noise. Selecting suitable hardwares like Turbocharger, EGR cooler at engine level to reduce NOx and Unburned Hydrocarbon Emissions with best Brake specific fuel consumption.

This study presents a method for a cool down simulation of passenger compartments. The purpose was to integrate the 3D Computational Fluid Dynamics (CFD) software StarCCM+ with the 1D thermal management software KULI. The targets were to achieve accurate prediction of temperature diffusion inside the cabin for a transient cycle simultaneously reducing the modelling effort and CPU-time consumption. The 1D simulation model was developed in KULI and the flow field data required to simulate mass flow and diffusion inside the cabin was implemented from Star CCM+. The simulation model consists of a multi-zone cabin and models the complete refrigerant circuit consisting of evaporator, condenser, Thermal Expansion Valve (TXV) and compressor. This paper describes the process flow, definition of the inputs required and finally the validation of the simulation data with experiments.

A methodology for design and development of radiator cooling fan is developed with an objective to improve underhood thermal management. For this purpose an Axial Fan Design Software has been developed which is based on Arbitrary Vortex Flow theory. The software is useful for obtaining initial blade design for the given basic functional requirements in terms of Airflow, Pressure Rise and Speed which defines the operating point of the fan. CFD analysis of the initial fan design is then carried out to predict the fan performance curve. Computation model resembles a fan set up in a wind tunnel. Further, Parametric Optimization is carried out using CFD to meet the functional requirements. A Rapid Prototype sample of the optimized fan design is manufactured and tested in a fan test rig made as per AMCA 210-99 standard to evaluate the fan performance curve and the power consumption.

In current competitive environment automobile industry is under heavy pressure to reduce time to market. First time right design is an important aspect to achieve the time and cost targets. CAE is a tool which helps designer to come up with first time right design. This also calls for high degree of confidence in CAE simulation results which can only be achieved by undertaking correlation exercises. In automobiles most of the structures are subjected to vibration from dynamic loads. All the dynamic road loads are random in nature and can be very easily expressed in terms of power spectral density functions. In the current scenario structural durability of the parts subjected to vibration is done partially through modal performance and partially though frequency response analysis. The only question that arises is what amplitude to use at what frequency and how to map all the accelerated tests dynamic load frequency spectrum to simulation domain.

October 2010 has brought major change over in Indian Auto Industries, with all India going BS-III Emission compliant (Metro with BS-IV Emission norms). During that time majority of the utility segment vehicles were having diesel engine with simple mechanical fuel injection system. To make these vehicles BS-III compliance cost effectively, with same fuel economy and reliability, was a challenging task. To enable this, Exhaust Gas Recirculation (EGR) through simple pneumatic EGR valve was the optimum technique. The EGR valve was controlled by means of simple Electronic Control Unit (ECU). Limitations of mechanical diesel fuel injection pump, stringent emission regulations, coupled with production constraints and variations, calls for robust control logics for governing EGR. The present work describes the robust strategies and logics of intelligent EGR governing of a 2.5 l, four Cylinder turbocharged, mechanical pump diesel engine for a BS-III compliant multi utility vehicle.

This article is focused on the development of hydrogen fuelled engine with detailed exposure on its derivation from base Compressed Natural Gas (CNG) engine to discuss the phenomenon on backfiring, control strategies (to avoid knocking and backfiring) and its performance, emission characteristics. In this work, timed manifold injection system was developed to have efficient control over the fuel supply. To achieve the best performance and emission out of the engine, governing parameter like injector pulse width and ignition timing were optimized at full load, part load and idling. For comparison of the results with the same engine experiments were also conducted with base fuel CNG and gasoline using the conventional fuel supply system. It was experimentally observed that engine when fuelled with Hydrogen (H2) produces less maximum power compared to CNG and gasoline.

To meet stringent US EPA - TIER IV final emission norms, the diesel engine manufacturers are using various technology approaches. These approaches are varying from advanced in-cylinder combustion strategies to sophisticated exhaust after-treatment technologies. Generally, the proven technology concepts such as Common Rail System (CRS), efficient Turbocharged-Intercooled (TCI), and controlled-cooled EGR along with DOC-DPF in after treatment are used for emission controls. However, this approach will increase the engine cost in addition to the Packaging challenges for the existing vehicle layouts. This paper describes the successful attempt to meet US EPA TIER IV final (<37 kW power category) emission norms on a 2.7 l, Naturally Aspirated (NA) diesel engine for off-highway application. Use of high pressure CRS system, moderate Excess Air Ratio (λ) and optimum engine swept volume selection helped to retain fuel consumption at par with interim TIER IV engine.