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Fun to drive, pick-up of vehicle, high acceleration feeling of vehicle, time to reach max velocities are some parameters prevailing in the passenger vehicle market. In addition to focusing on information about fuel economy declared by manufacturer, the customer also has drivability related criteria in his mind. Although drivability is subjective, it can be judged by using various parameters like maximum speed, pick-up feeling, overtaking acceleration, time to reach 0 – 100 km/h or 0 – 60 km/h, etc. While comparing two vehicles of the same segment, one vehicle may perform better on some of the parameters while losses on others. To decide overall drive performance of a vehicle based on various measured performance related parameters, a methodology is defined. This will help to understand the overall performance of a vehicle holistically and to compare its performance with other vehicles in a better way.

In a Passive suspension, a shock absorber generates damping force by pressurizing the oil flow between chambers. Typically, vehicle responds with suspension deflection, which significantly depends on damping forces and suspension velocity. Tuning dampers for various roads and steering input is an iterative balancing process. In any setting, damping force w.r.t velocity is tuned for optimum ride and handling performance. Practically, to achieve a balance between the two is a tedious task as the choices & arrangements of inner parts like piston, port, valve etc., which defines the forces set up [soft / hard] are almost infinite. The objective of this paper is to measure, objectify and evaluate the performance of two such optimum setting in various ride and handling events. A passenger car set up with an optimum soft & hard suspension damping force is studied for various ride and handling sub-attributes and their conflicts are examined in detail from a performance point of view:

The most widely used type of windshield wiper system employs a coil spring for wiper arm pressure generation. This spring is fixed between the arm head (fixed part) and wiper arm (moving part) and the tension in the spring is responsible for pressure generation. The present arrangement although being unsophisticated design, has following drawbacks: Inability to change wiper arm pressure according to change in vehicle speed. Inability to provide constant arm pressure during the complete range of motion along varying curvature of windshield. Inability to reduce/remove the continuous pressure on wiper blade when vehicle is parked for long durations resulting in permanent deformation of wiper blade rubber. This paper describes how electromagnets can be used to overcome the above stated inherent limitations of the windshield wiper system. An electromagnet is a device which produces magnetic field on application of electric current.

To cater the push towards “Vehicle Light Weighting”, both sprung and unsprung mass are being reduced. This results in reduced stiffness and thus has a profound undesirable effect on the overall vehicle handling. To understand the effect of different reduction ratios of sprung to unsprung mass; it is desired to understand how changes in stiffness affect the overall vehicle handling characteristics. Therefore, the study was conducted to experiment with different values of roll stiffness, at both front and rear axles and comparing the frequency response and phase change of Yaw Gain observed through a Pulse Input test. The present work is further correlated with subjective feedback to predict the shift in vehicle balance and handling characteristics.

Trunk lid (TL) can be opened using hydraulic or pneumatic balancers, coil springs, torsion bars or combination of the above. TL Opening Mechanism specific to Trunk Lid Torsion Bar (TLTB) is being discussed in the paper. After de-latching, TL should open smoothly and stop at such a height that it is visible from driver seat. The system consists of a four bar linkage mechanism, in which the fixed link is formed by BIW Bracket. Connecting link, TL Hinge Arm and Torsion bar arm form the other three links. Hinge has its one end attached to TL and the other end to BIW bracket. Torsion bar arm transfers torque to TL hinge through the connecting link. Major challenges in designing TLTB mechanism are part tolerances, C.G position and Weight variations in individual parts, Torsion bar Raw Material variation, uncertain friction in the system etc.

Riding comfort for automobile seating can be classified into two categories, long time riding comfort and short term riding comfort. The attributes that govern the riding comfort includes static spring constant and energy lost due to hysteresis. The emerging trend towards long term riding comfort could be governed by the above mentioned factors. The hysteresis loss characteristic is related to Poly-Urethane (PU) properties used extensively in automotive seating application. The nature with which the energy is released considering the same material and varying the hardness directly contributes to the comfort analysis for automobile seating and vice versa. Two curves can define the same area but the loading and unloading trend for the two cases could be different and so be the riding comfort. A conclusion would be drawn by obtaining hysteresis loss rate by changing the different parameters (hardness, density). One parameter would be varied by keeping the others constant.

Nowadays, Road Load Simulators are used by automobile companies to reproduce the accurate and multi axial stresses in test parts to simulate the real loading conditions. The road conditions are simulated in lab by measuring the customer usage data by sensors like Wheel Force transducers, accelerometers, displacement sensors and strain gauges on the vehicle body and suspension parts. The acquired data is simulated in lab condition by generating ‘drive file’ using the response of the above mentioned sensors [2]. For generation of proper drive file, not only good FRF but ensuring stability of inverse FRF is also essential. Stability of the inverse FRF depends upon the simulation channels used. In this paper experimental approach has been applied for the optimization of the simulation channels to be used for simulation of normal Indian passenger car on 4 corners, 6-Axis Road Load Simulator. Time domain tests were performed to identify potential simulation channels.

The biggest challenge in vehicle BIW design today is to make a light, cost effective and energy absorbing structure. With the increasing competition as well as increasing customer awareness, today’s vehicle has to satisfy several aesthetic and functional requirements besides the mandatory regulatory requirements. Working on global platform is challenging in order to comply with both pedestrian protection and low speed bumper impact (ECE-R42) and, at the same time, to meet the styling intent of reducing the front overhang. Pedestrian lower leg compliance demands space between bumper member and bumper: a condition that reduces the space available for energy absorption during low speed impact (ECE-R42). Therefore, reduction in front overhang poses a problem in meeting both the requirements with limited space. This paper outlines vehicle case study in order to optimize the design of Bumper Beam structure, for complying with regulatory requirements while satisfying the styling intent.

Automobile components are usually subjected to complex varying loads. Thus, fatigue failure is a common mode of failure in automobile components. Accurately predicting the fatigue life is the key point for light weight and also reliability design of automobile components. Various life prediction theories are being used in the automotive industry for damage analysis using material S-N curves. However, due to variability in manufacturing, material spec etc. it is difficult to predict the experimental lives using conventional theories. Probability based statistical modeling is prevalent in the industry for life prediction. Probabilistic plots of cycles to failure to constant amplitude loads are plotted and used for prediction purpose. As the component is subjected to varying loads in real world, defining a single parameter i.e. damage would be more relevant compared to loads.

Hybrid Electric Vehicle (HEV) Controls Development is an important aspect to realize the goals of Powertrain Electrification i.e. fuel economy and emission improvement. Keeping that in mind, development engineers need to formulate numerous control strategies. Once the control strategy is evaluated and frozen, it typically does not change from one vehicle model application to another. However, it may happen that Electronic Control Unit (ECU) manufacturer may change depending on the sourcing strategy. Therefore, in order to maintain uniformity, it may be required to compare control strategy of a finished ECU product frozen for one model application to be compared with new ECU sourced through another manufacturer. This paper discusses a methodology to compare control strategy of two ECU’s sourced from different ECU manufacturers with identical control requirements.

In the Indian Context, Fuel Economy of a vehicle is one of key elements while buying a Car. The fuel economy declared by OEMs (Original Equipment Manufacturers) is one of the key indicators while assessing the fuel economy. However it is based on a standard driving cycle and evaluated under standard conditions as mandated by emission legislation. As the driving pattern has a major influence on fuel economy, the objective of this paper is to study real world driving patterns and to define a methodology to simulate a real world driving cycle. A case study was done on Delhi City, by running a fleet of vehicles in different traffic conditions. Thereafter data analysis like acceleration %, specific energy demand per distance, Acceleration vs. Vehicle Speed distribution etc. was done with the help of MATLAB. The final validation of cycle was done by comparing Lab results with on-road Fuel Economy data.

A typical wheel development process involves designing a wheel based on a defined set of criteria and parameters followed by verification on CAE. The virtual testing is followed by bench level and vehicle level testing post which the design is finalized for the wheel. This paper aims to establish the learning which was accomplished for one such development process. The entire wheel development process had to be analyzed from scratch to arrive at a countermeasure for the problem. This paper will not only establish the detailed analysis employed to determine the countermeasure but also highlight its significance for the future development proposals. The paper first establishes the failure which is followed by the detailed analysis to determine the type of failure, impact levels and the basic underlying conditions. This leads to a systematic approach of verification which encompasses the manufacturing process as well as the test methodology.

Gear noise and vibration in automobile transmissions is a phenomenon of great concern. Noise generated at the gearbox, due to gear meshing, also known as gear whine, gets transferred from the engine cabin to the passenger cabin via various transfer paths and is perceived as air borne noise to the passengers in the vehicle. This noise due to its tonal nature can be very uncomfortable to the passengers. Optimizing micro-geometry of a gear pair can help in improving the stress distribution on tooth flank and reducing the sound level of the tonal noise generated during the running of the gearbox when that gear pair is engaged. This technical paper contains the study of variation in noise level in passenger cabin and contact on tooth flank with change in micro-geometry parameters (involute slope and lead slope) of a particular gear pair. Further scope of study has been discussed at the end of the paper.

Hardened steel is the majorly used raw material for automotive components. In spite of its abundance, its application is limited due to low fatigue life in dynamic loading. Shot peening is one of the identified processes to improve the fatigue life of the ductile steel by inducing the work hardening & surface improvement. The process of shot peening involves the bombardment of shots on the component surface. As the process & technique, the shot size selection plays very important role in the fatigue life improvement as it alters the results substantially. Also during the process, shot size decreases due to the normal wear of the shots after hitting the component surface. As a result, there is always a ratio of various sizes of the shots involved in the process. Therefore it becomes imperative to control the shot size ratio for obtaining the required work hardening & possible fatigue life improvement.

Road/Tire noise is an important product quality criterion for passenger cars which are driving customers to decide upon the selection of a vehicle. Reduced engine noise and improvement in road conditions has resulted into more road/tire noise problem as average vehicle speed has gone up. Excitations from road surface travelling through the tire/suspension to vehicle body (structure-borne path) and air-pumping noise caused by tread patterns (air-borne paths) are the main contributor to tire noise issue inside the vehicle cabin [1]. A lot of emphasis is put on the component level design as well as its compliance with vehicle structure to reduce the cabin noise. The objective of this work is to establish a methodology for evaluating structure-borne road/tire noise by evaluating the tire structural behavior and its interface with the vehicle body and its suspension system and identifying the contributing critical paths.

Vehicles which are sold and put into service in a country have to meet the regulations and standards of that country. Every country has a separate regulation and approval procedure which requires expensive design modifications, additional tests and duplicating approvals. Thus, there is the need to harmonize the different national technical requirements for vehicles and form a unique international regulation. With this rationale, the World Forum for Harmonization of Vehicle Regulations of the United Nations Economic Commission for Europe (UN/ECE/WP29) has brought governments and automobile manufacturers together to work on a new harmonized test cycle and procedure which is to be adopted around the world. This lead to the development of Worldwide Harmonized Light Duty Test Procedures (WLTP) and Cycles (WLTC). The test procedure is divided into 3 cycles, depending on a power to mass ratio of the tested vehicle.