Search Results

In a current competitive automotive market, weight and cost optimization is the need of an hour. Therefore it is important to explore use of alternative material which has less weight, low manufacturing cost and better strength. This paper presents methodology to achieve cost & weight reduction through use of Austempered Ductile Iron (ADI) instead of alloy forging. ADI casting has lower density, physical properties at par with alloy forgings and lower manufacturing cost. Pivot arm is the one of the critical component of twin axle steering system which transfers the hydraulic torque from steering gearbox to second forward axle via linkage system. In order to design lightweight pivot arm, existing chromium alloy steel material is replaced with the Austempered ductile iron (ADI). Pivot arm is designed and validated digitally as well as bench test and results are found to be meeting cost and weight targets.

With India achieving the BSVI milestone, the diesel particulate filter (DPF) has become an imperative component of a modern diesel engine. A DPF system is a device designed to trap soot from exhaust gas of the diesel engine and demands periodic regeneration events to oxidize the accumulated soot particles. The regeneration event is triggered either based on the soot mass limit of the filter or the delta pressure across it. For a Heavy Duty Diesel Engine (HDDE), pressure difference across the DPF is not usually reliable as the size of the DPF is large enough compared to the DPF used ina passenger vehicle diesel engine. Also, the pressure difference across DPF is a function of exhaust mass flow and thus it makes it difficult to make an accurate call for active regeneration. This demands for a very accurate soot estimation model and it plays a vital role in a successful regeneration event.

The steering system of commercial vehicle is asymmetrical to left side and rightside, this causes vehicle pull during braking application. This directly affects the safety of the driver and vehicle ride & handling performance. In a similar way, the asymmetrical suspension parameter unintentionally set during vehicle assembly arealso major contributors for creating a vehicle pull. After application of brake force, the tire contact patch creates a moment about the kingpin axis. However, this moment generated is different on left and right-side due to asymmetrical design parameters resulting in vehicle deviation from its intended path. A large deviation may lead to on road accidents. Some of the major factors which are responsible for the vehicle pulling phenomenon are the asymmetrical steering system compliance, asymmetrical suspension geometry, tire, braking system, road camber etc.

Small commercial vehicles (SCVs) are the drivers of a major part of India’s indirect economy, providing the most efficient means of transport. With the introduction of BS-VI norms, some major overhauls have been done to the SCV models to meet BS VI norms in challenging timeline for early market entry. This forced to automotive designers towards challenge of cost competitiveness as well as refinement level to survive in this competitive market. This paper explains the systematic approach used to overcome challenges of higher tactile vibrations, higher in-cab noise because of BS VI requirement in 2 cycle engine required for small commercial vehicle. The solutions were need to be worked out without compromising the other performance attributes like total cost of ownership, fuel economy, ease of servicing and cost effectiveness.

Polymers are substituting traditional materials, such as metals, in existing as well as new applications, both for structural and aesthetic applications as they are lightweight, customizable and are easy to mould into complex shapes. With such an extensive use of polymers, there is a need to carefully scrutinize their performance to ensure reliability. This is particularly the case in the automotive and electronic industries where the aesthetic appeal of their products is of prime concern and any visible scratch damage is undesirable. Concern for aesthetics has led to a need for the quantification of visibility due to scratch damage on polymeric surfaces Many painted plastic parts used in vehicles are being replaced with the molded-in color plastics for cost reduction and also due to environmental concerns associated with solvent emissions. There are multiple methods used for scratch evaluation of polymers and paints.

This paper highlights the transition of multi-axis suspension test rig from fixed reacted type to semi-inertial type and the benefits derived thereof in simulation accuracies. The critical influence of ‘Mx’ and ‘Mz’ controls on simulation accuracies has been highlighted. The vital role of ‘Mz’ control in the resonance of wheel pan along ‘Z’ axis and thereof arresting unwanted failures modes in spindle has been duly emphasized. Finally, the role of constraints and boundary conditions on simulation accuracies has been demonstrated by replacing the reaction frame with vehicle body.

Several sub-systems in a vehicle contribute to vehicle crashworthiness. One such system is the door latch and locking system. Correct functioning of this system is critical for facilitating occupant evacuation and preventing occupant ejection during crashes. Special care needs to be taken during vehicle safety development to achieve the desired intent. In crashes, it is observed that door opening or locking mainly occurs on account of inertial loads and deformation of the door structure. This paper studies the possible failure modes and their causes. Some likely solutions have also been discussed with a case study.

With the advent of most advanced diesel engines the demand for upgraded engine cooling modules capable of handling more heat rejection in a smaller space is surging. Moreover, the variance in the operating conditions, i.e., the simultaneous cooling demands for peak load as well as partial load in different ambient conditions of the vehicle operation, broadens the scope of development of a cooling system. Also, the cooling system needs to be configured judiciously so as to cater effective cooling at peak loads and efficient cooling at partial loads. This research paper deals with a cooling system developed using modularity approach in order to have a control over tuning of subsystems for varying operating conditions and also to achieve the performance targets with a compact design adhering to packaging constraints. Kuli simulation of different designed configurations were carried out for identification of best concept.

Small goods carrier and passenger vehicles powered by Naturally Aspirated (NA) Direct Injection (DI) diesel engines are popular in Indian automobile market. However, they suffer from inherently high radiated noise and poorly perceived sound quality. This paper documents the steps taken to reduce the radiated noise level from such an engine through structural modifications of major noise radiating components identified in the sound power analysis. The work is summarized as follows; Baseline radiated noise measurements of power train and identification of major noise sources through sound intensity mapping and noise source ranking (NSR) in an Engine Noise Test Cell (ENTC) Design modifications for identified major sources in engine structure Vehicle level assessment of the radiated noise in a Vehicle Semi-Anechoic Chamber (VSAC) for all the design modifications. A reduction of 7 dB at hot idle and 4 - 8 dB in loaded speed sweep conditions was observed with the recommended modifications.

The direct injection common rail technology coupled with variable geometry turbocharger on the modern diesel engine has improved the diesel engine performance (power and torque) greatly as compared to the conventional diesel engine. Diesel engine performance is greatly dependent on the abundant air availability. And it is facilitated by Variable Geometry Turbocharger (VGT) in modern engines. The engines with variable geometry turbocharger offer quick response to the demand in various driving conditions especially in transient driving conditions. During transient driving conditions, the air intake system experiences a rapid air flow pressure and velocity changes. The pressure differentials across air intake system during transient events allow flow direction changes in the system. This kind of phenomenon generates unusual “Multiple Whoosh” noises in the air intake system of the sport utility vehicle engine.

Lift axles of heavy commercial vehicles are deployed to handle increased payload. These axles of Commercial vehicles are made of low alloy carbon steel materials. Lift axles are designed in hollow condition for weight reduction opportunity. Two types of tube materials are used for the manufacturing of lift axles. These are either Cold Drawn Seamless (CDS) tubes or Hot Finished Seamless (HFS) tube material. The vanadium micro-alloyed steel grade, 20MnV6 is an excellent choice for the manufacturing of lift axles. The 20MnV6 has favorable mechanical properties for lift axles and also offers good weldability. However, lift axles made of 20MnV6 when manufactured in hot-finished condition, shows significant scatter in terms of durability performance. This requires further heat treatment of 20MnV6 to be deployed for reducing the scatter in the material properties to reduce scatter in durability performance and thus increasing the reliability of the lift axles.

Designing a cabin tilting system for Light Commercial Vehicles using a single torsion bar becomes challenging considering the operator safety and stringent design weight targets. Performance of a good tilting system entirely depends on cabin mass and location of centre of gravity with respect to (w.r.t) to tilting pivot point. Cabin Mass and COG location are very difficult to estimate while designing a new cabin as it is dependent on the maturation of all other cabin aggregates and also the accessories added by the customer. Incorporation design parameter changes like increasing cab tilting angle and increasing torsion bar length, in the later stages of product development, becomes expensive. The objective of this paper is to come up with an optimum design of a single torsion bar tilting employing “Taguchi optimization” for deciding the optimum levels of control factors, which ensures desired performance (i.e tilting effort vs.

This paper summarizes the approach towards the process of computational simulation of the intake system and its experimental investigation. It is an important aspect to improve breathing of the diesel engines for performance, torque smoothening and emissions. This can be achieved by optimizing intake system parameters such as plenum volume, diameters, length of ports & runners, etc., which directly correlates the volumetric efficiency, thereby the performance of the engine. Keeping the objective of improving volumetric efficiency to achieve low-end performance, the intake system design optimization has been done on a twin cylinder, four cycle, compression ignition, In-Direct Injection (IDI) engine. For the simpler intake system, the primary pipe length & diameter can be calculated by mathematical formula applying Helmholtz Resonator principle. But, for a complex intake system, simulation software is used here.

Currently, automotive industries are using Advanced High-Strength Steels (AHSS) sheet grades to achieve key requirements like light weighting and improved crash performance. But forming of AHSS grades becomes key challenge due to its lesser ductility and edge fracturing tendency during forming. In general, most of the automotive components undergoes shearing operations like blanking and punching which affects the edge ductility of the steel. AHSS grades possess limited edge ductility compared with conventional steel grades which results in edge fracturing due to tensile strain during stretch flanging operation. Stretch flange-ability is an important formability characteristic, which aids in material selection to avoid edge fracturing of complex shaped parts. Material with better stretch flange-ability possess better edge ductility and hence perform better in stretch flanging of sheet metal.

The Indian continental region encompasses various geographical terrains and climatic conditions, which necessitates automotive OEMs to build robust cabin climate control systems that ensure year round occupant comfort. Such systems comprise of, an on-board Heating Ventilation Air Conditioning (HVAC) sub-system and a control head (manual or automatic) that works as a user interface for adjusting parameters such as airflow, temperature and air directivity best suited to the occupants. In case of passenger cars, the on board HVAC system primarily serves two major purposes. To provide year round thermal comfort to the passengers and to enable defogging and defrosting action of front and rear windshield as per regulatory requirements and customer needs particularly for enhancing visibility in cold and humid ambient conditions.

Simultaneous reduction of NOx and PM from engine exhaust of a diesel engine is an interesting area of research due to the implementation of stringent emission regulations all over the world. Cost involved in expensive after treatment systems such as DPF and SCR necessitate minimization of engine out pollutants. With minimum engine out emission achieved through engine hardware and combustion parameter optimization, possibility of elimination or downsizing of the after treatment system can be explored. The paper presents the effect of fuel injection parameters and EGR rate on exhaust emission of a boosted diesel engine. Effects of parameters such as rail pressure, pilot-post injections, SOI, EGR rate and EGR temperature on a 4 cylinder two valve direct injection diesel engine is studied. Present study reveals the possibility of elimination of after treatment systems at BS IV level with optimization of engine hardware and combustion parameters.

Tire plays an important role in frontal impacts as it acts as a load path to transfer loads from barrier to side sill or rocker panels of passenger vehicles. In order to achieve better correlation and more reliable predictions of vehicle crash performance in CAE simulations, modeling techniques are continuously getting refined with detailed representation of vehicle components in full vehicle crash simulations. In this study, detailed tire modeling process is explored to represent tire dynamic stiffness more accurately in frontal impact crash simulations. Detailed representation of tire internal components such as steel belts, body plies, steel beads along with rubber tread and sidewall portion have been done. Passenger car tubeless radial tire was chosen for this study. Initially, quasi-static tensile coupon tests were carried out in both longitudinal and lateral direction of tread portion of tire.

The OEM's aim is to reduce development time and testing cost, hence the objective behind this work is to achieve a flexible stateflow model so that changes in the application during supply chain or development, on adding/deleting any switches, varying timer cycle, changing the logic for future advancements or else using the logic in different application, would end in minimal changes in the chart or in its states which would reflect least changes in the code. This research is about designing state machine architecture for chime/buzzer warning system and wiper/washer motor control system. The chime/buzzer stateflow chart includes various input switches like ignition, parking, seat belt buckle, driver door and speed accompanied with warning in the form of LED, lamp and buzzer. The logic is differentiated according to gentle and strong warning. Various conditions and scenarios of the vehicle and driver are considered for driver door and seat belt which is resolved in the chart.

Present stringent emissions norms; global fossil fuel energy scenario and competitive automotive market has driven many researches on diesel engine combustion in both academic and industry level. This work is an effort to improve the fuel economy without compromising emissions level of typical six cylinders inline CRDI diesel engine using optimized multiple injection strategy. There was some unusual nature of BSFC (Brake specific fuel consumption) observed on such typical engine. Also, Torque curve was not up to the mark for better drivability. This engine is equipped with most familiar in cylinder NOx reduction device namely EGR and multiple injections. There were few experiments conducted on same engine to optimize the BSFC using different multi injection strategies in line to marginal change of injection timing with respect to crank angle. Total exercise was done following partial Design of Experiments (DOE). EGR % has kept unaltered.

The automotive industry is facing a challenge as efficiency improvements are required to address the strict emission norms which in turn requires high performance downsized, lightweight IC engines. The increasing demand for lightweight engine needs high strength to weight ratio materials. To meet high strength to weight ratio, castings are preferable. However due to strength limitations for critical crankshaft applications, it forces to use costly forgings such as micro alloyed forging steel and Martensitic (after heat treatment) forging steel. To reduce the cost impact, high strength Austempered Ductile iron (ADI) casting is developed for crankshaft applications to substitute steel forgings. Austempered Ductile Iron is having an excellent mechanical properties due to aus-ferritic structure. The improved properties of developed ADI Crankshaft over steel forged crankshaft offers additional weight advantage.