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Regenerative braking is an effective approach for electric vehicles (EVs) to extend their driving range. To enhance the braking performances and regenerative energy, regenerative braking control strategy based on multi objective optimization is explained in this paper. This technical paper would be focusing on extracting optimum Range with effective brake performances without affecting drivability and performances in different drives modes. An extensive research study on public road driving patterns is done to understand the percentage utilization of brakes at various (low-mid-high) speeds as per the customer driving behavior. Multi-Objective optimization function with three vital factors is defined where output generated power, torque smoothness and current smoothness are selected as optimization objective to improve the driving range, braking comfort, and battery lifetime respectively.

In the current era, vehicle manufacturers focus has increased towards passenger comfort and one of the key areas is NVH. Vehicle level NVH targets are cascaded to component level for obtaining better refinement in cabin. One such performance attribute is sloshing noise of urea in diesel vehicles. Migration from BS4 to BS6.2 norms demand complex technological changes to automobile manufacturers to add extra components to the vehicles which is a big challenge in identifying the locations at critical stage of the project phase. In one of the developments of mid SUV category vehicle, sloshing noise from urea tank is perceived as objectionable during low-speed braking and while passing over speed breakers. This paper addresses the measurement conditions of sloshing noise and its evaluation procedure to quantify the sloshing noise at vehicle level. The sloshing noise is perceived in the frequency band of 50 to 1000 Hz.

Reducing material wherever there is a possibility in automobile industry is inevitable for weight and cost saving. This paper explains about the possibilities of optimizing the material composition of automotive Headliners (also called as Roof liners) without affecting the performance and safety criteria. In this paper, we are targeting at optimizing the individual constituents of a composite Headliner. A conventional Headliner comprises of many sandwich layers of which PU foam shares the major percentage of the composition contributing to 80% of the Headliner thickness. In this paper, we are discussing about the optimization done in Headliner sandwich constituents without affecting the core performance parameters of headliner such as curtain airbag deployment, ergonomic regulations, drop test etc. By incorporating this change, without significant changes in other layers, overall weight reduction of ~24% and overall cost reduction of ~24% is achieved.

Globally all OEMs are moving towards electric vehicle to reduce emission and fuel cost. Customers expect highest level of refinement and sophistication in electric vehicle. At present, the customers are sensitive to high pitched tonal noise produced by electric powertrain which gives a lot of challenges to NVH engineers to arrive at a cost-effective solution in less span of time. Higher structure borne tonal noise is perceived in electric vehicle at the vehicle speeds of ~ 28 kmph, 45 kmph and 85 kmph. The test vehicle is front wheel drive compact SUV powered by motor in the front. The electric drive unit is connected to cradle and subframe with help of three mounts. Transfer path analysis (TPA) using blocked forces method is carried out to identify the exact forces of the electric drive unit entering the mounts. Powertrain mount is characterized by applying the predicted forces and dynamic stiffness at problematic frequency is measured.

In automotive market, with competitive car prices, build quality of a car will be a major distinguishing factor. Consumer's need for acoustic comfort has evolved from the removal of annoying noises to perceived sound quality. Operational sounds from electromechanical systems like sunroof system, window regulator, door lock system, HVAC etc. directly interact with users’ senses. The perceived acoustics comfort of these sounds are direct indicators of vehicle character and can influence customer’s buying decision. With the reduction in product development time and stringent cost constraints, a proper structured target setting methodology to benchmark & evaluate these operational sounds is crucial. In this paper, such a target setting methodology is proposed and discussed for operational sound quality evaluation. Electromechanical noises from various vehicles are measured using binaural head measurement system.

The test vehicle is All Wheel Drive (AWD) vehicle which is powered by four-cylinder engine. The power is transferred from the powertrain to the wheel through power transfer unit (PTU), propeller shaft, flexible rubber coupling and Integrated Rear Differential Assembly (IRDA) . Higher boom noise and vibration levels are observed when driving the vehicle in 4th gear WOT conditions. NVH levels are dominant between 1150 rpm to 2100 rpm and at 2200 rpm in 2nd order and 4th order respectively. Operational deflection shape (ODS) analysis is carried out on entire vehicle to identify the location where maximum deflection is observed at the problematic frequency. It is identified that higher torsional excitation from the powertrain is exciting the IRDA pitching mode and the propeller shaft bending mode which is the reason for higher 2nd order and 4th order NVH levels. The driveline forces are entering the body through the IRDA and rear cradle bushes.

Electric vehicles (EV) are much quieter than IC engine powered vehicles due to less mechanical components and absence of combustion. The lower cabin noise in electric vehicles make customers sensitive to even small noise disturbances in vehicle. Road boom noise is one of such major concerns to which the customers are sensitive in electric vehicles. The test vehicle is a front wheel driven compact SUV powered by electric motor. On normal plain road, noise levels are acceptable but when the vehicle has been driven on coarse road, the boom noise is perceived, and the levels are objectionable. Multi reference Transfer Path Analysis (MTPA) is conducted to identify the path through which maximum forces are entering the body. Based on MTPA, modifications are proposed on the suspension bushes and the noise levels were assessed.

In the current automobile era, weight, emission, and fuel efficiency were driving the overall powertrain development without compromising on the performance. Due to light weight and high-performance engines, the increased level of excitations in terms of torsional, axial, and bending frequency on crank shaft during combustion is inevitable. The axial and bending moment exerted from crankshaft during combustion causes vibration of the clutch diaphragm spring, in turn these vibrations are transferred through the hydraulic release system to clutch pedal which induces undesirable pedal pulsation and vibration during clutch pedal operation. The subjective perception on Noise Vibration and Harshness (NVH) becomes more essential in the Vehicle development process of modern high-performance vehicles.

Customers expect more advanced features and comfort in electric vehicles. It is challenging for NVH engineers to reduce the vibration levels to a great extent in the vehicle without adding cost and weight. This paper focuses on reducing the tactile vibration in electric vehicle when AC is switched ON. Vibration levels were not acceptable and modulating in nature on the test vehicle. Electric compressor is used for cabin cooling and battery cooling in the vehicle. Compressor is connected to body with the help of isolators. Depending upon cooling load, the compressor operates between 1000 rpm and 8000 rpm. The 1st order vibration of compressor was dominant on tactile locations at all the compressor speeds. Vibration levels on steering wheel were improved by 10 dB on reducing the dynamic stiffness of isolators. To reduce the transfer of compressor vibration further, isolators are provided on HVAC line connection on body and mufflers are provided in suction and discharge line.

In developing countries, the commercial vehicle industry is one of the key drivers for economic growth. The commercial vehicle industry in India is expected to reach 11,80,000 units by 2025 with a CAGR of 18% from CY 2020 to CY 2025 [1]. In the price sensitive segment of small commercial vehicles, it is imperative to incorporate accurate fuel economy measurement techniques during product development stage to deliver maximum value to the customer. In this approach, measuring the fuel consumption of small commercial vehicles in real world driving conditions in real time is one of the most critical aspects in engine calibration development and fine tuning. One of the challenges in measuring fuel consumption in sub 1 liter diesel engines is the very low fuel flow rate in the fuel feed line which keeps varying as per the driver demand.

Multidisciplinary Design Optimization (MDO) of an automobile body structure is a challenging task as it involves multiple, often conflicting requirements of safety, durability & NVH. Conventionally MDO process requires running large number of design of experiments (DOE) to explore the full design space and to build response surface for optimization. As the safety simulations are highly nonlinear in nature, they typically require significant amount of computational time and resources. Hence the conventional MDO approach is too expensive if too many design variables are simultaneously considered. In this paper, an alternative approach using Equivalent Static Load (ESL) method has been suggested for MDO which is quicker & accurate. The basic idea of the Equivalent Static Load-Method (ESL) is to divide the original nonlinear dynamic optimization problem into an iterative linear optimization and nonlinear analysis process.

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.

Sound package material selection plays a vital role in maintaining passenger comfort by suppressing noise inside cabin. Sound package development in static condition minimizes the extrinsic variables which influence the measurements. The consideration of static condition favors simulation and its correlation with test data. Once correlation is achieved, simulation inputs are used for further optimization and improvements. Noise control can be done in three levels by working either on source, path or receiver. In automobiles, there are many sources of noise such as engine, tire and wind. This topic deals with quantification of various transfer paths between source and receiver location using Power Based Noise Reduction (PBNR) method. This methodology is used in both simulation and testing along with its overall scope for improvement. It is best to quantify path strength in terms of energy levels instead of mere amplitude due to its independency on external test conditions.

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.

Traffic awareness of the driver is one of the prime focus in terms of pedestrian and road safety. Driver experience plays a significant role and driving requires careful attention to changing environments both within and outside the vehicle. Any lapse in driver attention from the primary task of driving could potentially lead to an accident. It is observed that, lack of attention on the ongoing traffic and ignorant about the traffic information such as traffic lights, road signs, traffic rules and regulations are major cause for the vehicle crash. Traffic signals & signage are the most appropriate choice of traffic control for the intersection, it is important to ensure that driver can see the information far away from the intersection so that he/she can stop safely upon viewing the yellow and red display. Then, upon viewing the signal operations and conditions the motorist can stop his/her vehicle successfully before entering the intersection.

Achieving comfortable Ingress-Egress (I/E) is a major ergonomic challenge for Occupant packaging engineers during vehicle design. Vehicles should be designed so that the targeted drivers are able to comfortably get in and out of it. Simulating occupant ingress/egress motion for vehicle involves many constraints and capturing actual behavior of human motion is cumbersome. In recent years, there are number of studies to investigate occupant ingress/egress motion and to understand perceived discomfort, influence of specific design parameters, age impact etc. These studies majorly used techniques like real time motion capturing in a vehicle mockup, comparison of joint torques developed during the ingress/egress motions etc., to identify the occupants discomfort aspects. This paper aims to capture the ingress/egress influencing parameters and incorporating the parameters in vehicle architecture layout during concept phase itself considering various anthropometric measurements.

With continuous pressure for reducing vehicle development time and cost, without compromising on system reliability, it is imperative to move from Road to Lab to Model (RLM) based development. Every OEM is currently using virtual environment to complete functional checks of systems during development. The method of developing control functions and calibration in virtual environment brings repeatability and reproducibility which typically is challenging in real world testing. This process is cost effective and optimizes the time for development and brings high level of system maturity before testing it in the vehicle. This paper focuses on defining a front-loading approach for setting up of virtual test environment. Development of virtual test environment and its validation with respect to real vehicle data will be discussed, with focus on vehicle plant model and driver model.

OEMs these days are focusing on front loading the activities to Virtual Test Environment (VTE) based development owing to high development cost and complexity in achieving repeatability during testing phase of vehicle development,. This process not only helps in reducing the cost and time but also helps in increasing the maturity and confidence level of the developed system before actual prototype is built. In the past, extensive research has happened for increasing the fidelity of VTE by improving plant model efficacy which involves powertrain and other vehicle systems. On the other hand, improving the precision of driver model which is one of the most complex nonlinear systems of virtual environment still remains a challenge. It is apparent that various drivers show different behavior in real world for a given drive profile. While modelling a driver for a VTE, the real world driver attributes are seldom considered.

In-vehicle displays such as an instrument cluster in a vehicle provide vital information to the user. The information in terms of displays and tell-tales needs to be perceived by the user with minimal glance during driving. Drivers must recognize the condition of the vehicle and the state of its surroundings through primarily visual means. Drivers then process this in the brain, draw on their memory to identify problem situations, decide on a plan of action and execute it in order to avoid an accident. There are visual hindrances seen in real world scenario such as obscuration, reflection and glare on the instrument cluster which prevents the vital information flow from vehicle to the driver. In order to ensure safety while driving, the instrument cluster or driver displays should be placed in an optimized location. This paper deals with how to achieve a visual hindrance free cluster position in a vehicle to protect the important information flow from the vehicle to the driver.

Idle NVH (Noise Vibration Harshness) is one of the major quality parameters that customer looks into while buying the vehicle. Idle shake is undesirable vibrations generated from Engine while it is in idling condition. These low frequency vibrations affects both driver and passenger comfort. Vibrations are perceived by customer through the interfaces such as the seats, floor, and steering wheel. The frequencies of vibration felt by customer ranges between 10-30 Hz and varies based on engine configurations. There are two factors that are critical to the vehicle idle NVH quality, 1. Engine excitation force and 2. Vehicle sensitivity to excitation forces (Transfer function). Even though the engine excitation forces are governed by cylinder combustion process inside the cylinder and engine mass, it is also largely affected by how well the engine and transmission are supported on vehicle through isolators.