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Electric cars are the future of urban mobility which have very less carbon foot print. Unlike the conventional cars which uses BIW (Body in White), some of the electric cars are made with a space frame architecture, which is light weight and suitable for low volume production. In this architecture, underbody consists of frames, battery pack, electronics housing and electric motor. Underbody drag increases due to air entrapment around these components. Aerodynamic study for baseline model using CFD simulations showed that there was a considerable air resistance due to underbody components. To reduce the underbody drag, different add-ons are used and their effect on drag is studied. A front spoiler (air dam) is used to deflect the incoming air towards sides of the car. A under hood cover for front components, trailing arm cover for trailing arm and rear bumper cover for rear components were used to reduce underbody drag.

The purpose of this study is to conduct dynamic seat pressure mapping on vehicle seats during its operation on different test tracks under ambient environmental conditions for a defined speed. The test track comprises of pave roads, high frequency track, low frequency track and twist track. The variations in pressure distribution on seat during diverse road load inputs help to understand the seat cushion and back comfort for unique percentiles of human subjects ranging from 50th to 95th percentile population. For conducting the study, a sport utility vehicle (SUV) loaded with leatherette seats has chosen. Totally six participants (human subjects), five male and one female selected for the study based on their BMI (Body mass index) and body morphology. Pressure mats suitable for taking dynamic load inputs and able to log the data at a defined sampling rate mounted on seats and secured properly. The pressure mats should cover the seat cushion, bolster areas and back seat completely.

Synchronizer is the key element for the smoother gear shift operation in the constant mesh transmission. In the gear shift operation, the double bump occurs at the contact between the sleeve teeth and the clutch body ring teeth after the full synchronization. The double bump is random in nature and the dynamics is difficult to predict. The double bump gives a reaction force to the driver and affects the gear shift quality. This paper focus on the sensitivity analysis of the synchronizer ring index percentage and the clutch body ring asymmetric chamfer angle to reduce the occurrence and magnitude of the double bump. The system level simulation model is developed using 1D simulation tool. The modeling is done after complete declutching event so that there is no power supply to the transmission. The model can handle both upstream and downstream reflected inertia depending upon the gear shift event.

Closed crankcase ventilation prevent harmful gases from entering atmosphere thereby reducing hydrocarbon emissions. Ventilation system usually carries blowby gases along with oil mist generated from Engine to Air intake system. Major sources of blowby occurs from leak in combustion chamber through piston rings, leakage from turbocharger shafts & leakage from valve guides. Oil mist carried by these blowby gases gets separated using separation media before passing to Air Intake. Fleece separation media has high separation efficiency with lower pressure loss for oil aerosol particles having size above 10 microns. However, efficiency of fleece media drops drastically if size of aerosol particles are below 10 microns. Aerosol mist of lower particle size (>10 microns) generally forms due to flash boiling on piston under crown area and from shafts of turbo charger due to high speeds combined with elevated temperatures. High power density diesel engine is taken for our study.

Transmission quill gears are hot forged steel parts often used in constant mesh manual transmissions. The quill gear, which helps to transmit the power from input drive shaft to output shaft through driving gears. It’s having external teeth which is positively engaged with driving gear and sleeve. During gear selection sleeve take load from input shaft and transmit to driven gear. Quill gear directly engaged with driving gears on outer surface and bearing in inner surface which needs to have high strength and durability. These properties can be improved by carburization heat treatment in existing design such processes can lead to increased costs. We have developed quill gear through powder metallurgical process and then cooled rapidly in the furnace to get high strength and wear properties. Material composition are optimized to suit for sinter hardening process conditions.

Regulations on pedestrian safety have been introduced globally since the year 1990 and in India it will have to be met around the year 2016. Process of making vehicle compliant to this regulation requires rigorous design development and testing. Testing involves propelling head-forms (Child and Adult) on bonnet at 35 km/h and 40 km/h and leg-forms (Upper and Lower) on bumper at 40 km/h according to the different National / International / NCAP regulatory requirements A pedestrian protection test rig has been indigenously designed and developed in-house to perform pedestrian protection impact testing in-house. The paper describes the salient features of the pedestrian protection test rig, its functioning, operation and process of acquiring the data for determination of the values required by crash safety regulations.

Light weight and Robust manufacturing technologies are always needed for transformation drive in the Automotive industry for the next-generation vehicles with greater Power to weight ratio. Innovations and process developments in materials and manufacturing processes are key to this light weighting transformation. Aluminium material has been widely used for these light weighting opportunities. However, aluminum joining techniques, characterized by their poor quality and consistency are limiting this transformation. This technical paper represents one of such case, where the part is made up of Aluminium through conventional casting route which has affected the laser weld quality due to poor casting soundness. This experiment explains in detail about the importance of Casting soundness for laser weld quality, weld penetration, strength etc., and the Product consistency.

A vehicle drifts due to several reasons from its intended straight path even in the case of no steering input. Vehicle pull is a condition where the driver must apply a constant correction torque to the steering wheel to maintain a straight-line course of the vehicle. This paper presents an investigation study into the characteristics of a vehicle experiencing steering drift. The aim of the work is to study vehicle stability and the causes of vehicle drift/pull during straight line to minimize vehicle pull level and hence optimize safety measures. A wobble in the steering wheel feels like the steering wheel is shaking to the left and right. This may get worse, if speed increases. This paper focuses on modelling and evaluating effects of suspension parameters, differential friction, brake drag variation, Unbalanced mass in the wheel assembly and C.G. location of the vehicle under multibody dynamic simulation environment.

Drive cycles have been an integral part of emission tests and virtual simulations for decades. A drive cycle is a representation of running behavior of a typical vehicle, involving the drive pattern, road characteristics and traffic characteristics. Drive cycles are typically used to assess vehicle performance parameters, perform system sizing and perform accelerated testing on a test bed or a virtual test environment, hence reducing the expenses on road tests. This study is an attempt to design a relatively robust process to generate a real world drive cycle. It is based on a Six Sigma design approach which utilizes data acquired from real world road trials. It explicitly describes the process of generating a drive cycle which closely represents the real world road drive scenario. The study also focuses on validation of the process by simulation and statistical analysis.

The global automotive industry is growing rapidly in recent years and the market competition has increased drastically. The engines with high torque delivery and deeper transmission ratios has become more and more common for a pleasant drivability experience. In a market highly driven from a comfort and an economic point of view, it is essential to develop a transmission and its components in an optimal way. One of the Unique Selling Point (USP) of a vehicle is the gear shift quality & it is highly important to have an optimum shift quality for an enhanced customer experience. Synchronizer plays a vital role for gear shifting performance in manual gearbox without any shifting assistance. The primary function of a synchronizer is to reduce the RPM difference between two gears before gear shifting with minimum time.

Ride is essentially the outcome of coupled dynamics of various involved sub-systems which make it too complex to deal analytically. Tires, amongst these, are known to be highly nonlinear compliant systems. Selection of tires specifications such as rated tyre pressure, etc. are generally decided through subjective assessment. While experts agree that tyre pressure affects the attributes such as ride to a noticeable degree, the quantification of the change often remains missing. In the current work, vibration levels of various sub-systems relevant to ride in an SUV are measured for three different tyre pressures at different speeds over the three randomly generated roads. For the purpose, artificial road profiles of classes A, B and C are synthesized from the spectrum of road classes defined in ISO 8608:2016 and reproduced on a four-poster test rig.

This paper establishes quick and accurate methods to experimentally determine the rigid body properties of a powertrain unit namely, the centre of gravity, the moment of inertia and the torque roll axis and also the rigid body dynamics of mounting system such as the rigid body modes, kinetic energy distribution, and elastic roll axis. The centre of gravity is determined using single point suspension and laser pointer to locate the axis passing through the centre of gravity. A special unifilar pendulum test rig is developed for determining the moment of inertia where an accelerometer measures the rotational oscillations for a given time period and the moment of inertia is determined by solving a set of inertial ellipsoid equations. An easy method of reorienting the powertrain is demonstrated in this paper.

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.

The implementation of TREM/CEV 5 emission norms on farm equipment will bring in cost pressure due to the need for exhaust after treatment systems. This cost increase needs to be reduced by bringing in more efficient and effective processes to shorten the development phase and to provide better fuel efficiencies. In this work ETAS ASCMO Online DoE with Constraint Modelling (ODCM) was applied to execute smart online DoE on a new common rail diesel engine with EGR, whose exact bounds of operation was not available. A Global test plan with ASCMO Static was created without much focus on detailed constraints of engine operation, other than the full load curve. The parameters which were selected were Speed, Torque, Rail Pressure, Main Timing, EGR Valve Position, Pilot Separation and Quantity and Post Quantity and Separation. For these parameters, the safe operating bounds were not available. This ASCMO Static test plan is automated and executed on engine test cell with ETAS INCAFlow.

This work discusses about the emission development of a 4 cylinder inline 3.3 liter CRDe to meet BS III emission norms applicable to 3.5 Ton and above category and upgradable to BS IV emission by suitable after treatment. This engine is developed from a 3.2l mechanical pump engine. During development the focus was on the usage of higher swept volume, selection of engine hardware like piston bowl, turbocharger, injectors and optimization of the injection parameters. A cost-effective solution for meeting the BS III norms in the LCV category without application of EGR and exhaust after treatment even though there is 15% increase of the power rating and 10% increase in Peak torque of the engine. Injection parameters like injection timing, injection quantity and pilot injection were optimized to meet the emission target.

Validation of vehicle structure is at the core of reduction of product development time. Robust and accelerated validation becomes an important task. In service the vehicle is subjected to variable loads. These act upon the components that originate from road roughness, manoeuvres and powertrain loads. Majority of the body in white and chassis structural failures are caused due to vertical loading. Measured road load data in test track have variable amplitude histories. These histories often contain a large percentage of small amplitude cycles which are non damaging. This paper describes a systematic approach to derive the compressed load cycle from the measured road load data in order to produce representative and meaningful yet economical load cycle for fatigue simulation. In-house flow was developed to derive the compressed load time history.

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.

The inherent capacity of electric motors to generate substantial instant torque can lead to significant load reversals in electric vehicle driveshafts under specific road conditions and driving maneuvers, highlighting the need for targeted improvements in driveshaft design, particularly in optimizing joint sizing. This paper presents a systematic approach to investigate the root causes of a catastrophic driveshaft failure that occurred during specific vehicle tests on a road with multiple speed bumps, resulting in numerous high torque reversals. The objective was to enhance system robustness through changes in driveshaft design and the manufacturing process, coupled with a software calibration technique to reduce torque demands under such operating conditions. The process encompassed torque measurements at the vehicle level, failure replication on a test rig, and correlation with simulations.

Commercial transportation is the key pillar of any growing economy. Light and Small commercial vehicles are increasing every day to cater the logistics demand, but there is always a gap between customer’s actual and desired operational efficiency. This is because of lack of organized fleet and efficient fleet operation. The major requirement of fleet owners is timely delivery, high productivity, downtime reduction, real time tracking, etc., Automakers are now providing fleet management application in modern LCV & SCV to satisfy the fleet operator requirement. However, any feature malfunction, consignment mismatch, wrong notification, missed alerts, etc., can incur huge loss to fleet operator and disrupt the entire supply chain. Hence it is very critical to extensively validate the telematics features in fleet management application. This paper explains the approach for exhaustive validation strategy of fleet management applications (B2B) from end user perspective.

BS6.1 emission standards were implemented in India in 2020 followed by BS6.2 which added more controls on emission limits. For BS6.2 OBD (On Board Diagnostics) and RDE (Real Driving Emission) were added on to the existing BS6.1 emissions. Emission control changes usually need addition of new parts, calibration changes and durability requirements. For the current 1.5L, 3-cylinder diesel engine an pSCR (Passive Selective Catalytic Reduction) brick was added for control of NOx for meeting RDE. For meeting OBD requirements PM (Particulate Matter) and NOx sensors were added in the cold end pipe along with calibration changes to meet the BS6.2 norms. In this paper we will discuss on the design aspects of sensors and pSCR only. The sensor and pSCR positioning plays vital role in meeting the legislative requirements and to ensure the ease of assembly and durability of the parts.