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Technical Paper


Keywords – Miniaturization, Low Profile (LP) Relays, Low Profile (LP) Fuses, Fuse box, Wiring Harness Research and/or Engineering Questions/Objective With the exponential advancement in technological features of automobile’s EE architecture, designing of power distribution unit becomes complex and challenging. Due to the increase in the number of features, the overall weight of power distribution unit increases and thereby affecting the overall system cost and fuel economy. The scope of this document is to scale down the weight and space of the power distribution unit without compromising with the current performance. Methodology Miniaturization involves replacing the mini fuses and J-case fuses with LP mini and LP J-case fuses respectively. The transition doesn’t involve any tooling modification and hence saves the tooling cost.
Technical Paper

Fuel Efficiency Improvement in Automatic Transmissions by Lockup Slip Methodology

Increasing of automatic transmissions in passenger cars is based on pleasure of driving, smooth acceleration and easy operation makes the customer satisfaction. Challenges beyond 2020 is BS VI emission norms in India - a very tough goals on CO2& NOx reduction in Gasoline & Diesel vehicles. But its setback in lower fuel economy. To support & enhance fuel economy in Automatic transmissions as part of drivetrain technologies, this article discusses about the power losses in torque converters and experiments on the actual Automatic transmission (AT) vehicle on-road to understand the real city driving behavior in the aspects of gear utilization & gas pedal utilization throughout the entire traffic conditions. With that data research, slip area and slipping conditions is determined & clutch slip control is enabled at area in torque converter by ensuring that NVH parameters are not affected.
Technical Paper

Aerodynamic Drag Reduction of an Intercity Bus through Surface Modifications - A Numerical Simulation

The maximum power produced by the Engine is utilized in overcoming the Aerodynamic resistance while the remaining has been used to overcome rolling and climbing resistance. Increasing emission and performance demands paves way for advanced technologies to improve fuel efficiency. One such way of increasing the fuel efficiency is to reduce the aerodynamic drag of the vehicle. Buses emerged as the common choice of transport for people in India. By improving the aerodynamic drag of the Buses, the diesel consumption of a vehicle can be reduced by nearly about 10% without any upgradation of the existing engine. Though 60 to 70 % of pressure loads act on the frontal surface area of the buses, the most common techniques of reducing the drag in buses includes streamlining of the surfaces, minimizing underbody losses, reduced frontal area, pressure difference between the front & rear area and minimizing of flow separation & wake regions.
Technical Paper

Tractor Transmission Validation for Synchronizer as Skid at Rig Level

Synchronizer design optimization is being prime need for smooth gear shifting and shifting noise. Especially in tractors, synchronizers are subjected to different kinds of loads under various field applications such as Puddling, Cultivation, Haulage, Construction equipment, etc. Also, transmission housings act as a part of chassis of the tractor and hence subjected to sever bending loads. Thus, design & evaluation of tractor transmission, meeting the customer requirement is quite complex. Current trends in product development are driven by shortening development time, reduced cost and first-time-right principle. These above requirements drive tractor manufacturers to put more efforts on delivering quality, robust and reliable transmission assembly in time. Generally the synchronizer packs were validated at sub system level in test rig and further assembled on to the tractor to validate the same in tractor level it requires more time & high cost.
Technical Paper

Green Drive - A Holistic Approach Towards Fuel Efficient Driving

In the past few decades, improvement on fuel efficient technologies have progressed rapidly, whereas little emphasis is being made on how the vehicle should be driven. Driving habits significantly influences fuel consumption and poor driving habits leads to increased fuel consumption. In this paper a new system called “Green Drive” is being presented wherein driving habits are closely monitored, evaluated and details are systematically presented to the user. Green Drive system monitors key driving parameters like speed, gear selection, acceleration, unwanted engine idling periods, aggressive braking and clutch override and presents an ecoscore on the infotainment system which is reflection of users driving behavior. The system also offers guidance on the scope for improving driving habits to achieve better ecoscore and hence reduced fuel consumption.
Technical Paper

Experimental Measurement to Predict Power Steering Pump Hub Load with Implementation of Belt Driven Starter Generator

The present scenario in automobile industry is formed on developing smart vehicles by introducing various feature towards fuel efficient, low emission, weight reduction, and advance safety feature with hybrid and micro-hybrid vehicles. One such feature gaining more popularity is the Belt Driven Starter Generator [1] for its contribution towards fuel efficiency, emission reduction [2], weight reduction and convenient packaging with engine/electrical interface. However this invention puts challenge of integration and increase in loading to various system like power steering pump and crank shaft pulley, as all these systems are interlinked with a common belt. In this interface links we observed the steering pump hub under risk of structural failure due to additional load to support Belt Driven Starter Generator. Failure to identify safe limits of hub load can affect safe vehicle operation [3].
Technical Paper

Analytical Design and Development for Automobile Powertrain Mounts Using Low Fidelity Calculators

The excitation to a vehicle is from two sources, road excitation and powertrain excitation. Vehicle Suspension is designed to isolate the road excitation coming to passenger cabin. Powertrain mounts play a vital role in isolating the engine excitation. The current study focuses on developing an analytical approach using Low-Fidelity computer programs to design the Powertrain Mount layout and stiffness during the initial stage of product development. Three programs have been developed as a part of this study that satisfy the packaging needs, NVH requirements and static load bearing requirements. The applications are capable of providing the Kinetic Energy Distribution and Static Analysis (Powertrain Enveloping and Mount Durability) for 3-point and 4-point mounting systems and the ideal mount positions and stiffness for 3-point mounting systems.
Technical Paper

Approach to Estimate Life of Li-Ion Power Battery for Mild Hybrid Application in India

Development of Hybrid Electric Vehicles (HEVs) and Battery Electric Vehicles (BEVs) is gaining traction across all geographies to help meet increasing fuel economy regulations and as a pathway to offset concerns due to climate change. But HEVs and EVs have so far been a nascent market for India. These technologies have primarily shifted towards Lithium-ion batteries (LIB) for energy storage due to its high energy and power densities. In order to make actual business sense of these technologies, of which, battery is a major cost driver, it is necessary for these batteries to provide similar performance and life expectancy across the operating boundary of the vehicles, as well as provide the requirements at a competitive cost. In other words, the LIBs have to sustain the normal life cycle requirements and withstand wide range of storage temperatures that the conventional gasoline/diesel vehicles have been good at and still ensure good life.
Technical Paper

Optimization of Tip-In Response Character of Sports Utility Vehicle and Verification with Objective Methodology

Each OEM has a distinguishing drivability character that defines its image in the market to achieve brand differentiation. Drivability is one of the important factors along with fuel economy that determines the success of a vehicle vis-à-vis its competitors. It can be said that the need for good drivability among customers is increasing day by day similar to the need for high fuel economy. Drivability is the response that a vehicle delivers to the inputs of the driver which are mainly accelerator, brake, clutch, gear and steering. The dynamic response of the vehicle is mainly in terms of velocity and acceleration. The way the response is delivered will characterize the drivability of a vehicle. The drivability event discussed in this paper is throttle tip-in response which is one of the critical evaluation factors for defining the character of a Sports Utility Vehicle.
Technical Paper

Cost Efficient Bharat (Trem) Stage IV Solutionsfor TractorEngines

India's high Air Pollution level is the focus of discussions as we grow. Plans to combat this menace and implement the latest Technologies are gathering pace. The increasingly stringent emission legislations provide a continuous challenge for the non-road market. Tractor manufacturers are evaluating the need for cost-effective technology to meet upcoming stringent emissions targets. Simply following global approach may not work for Indian market considering the customer usage pattern & perceptions. With an anticipation of upcoming emission norms being based on US-EPA TIER-4 final up to 75 Hp, major technology up gradation is expected for farm equipment sold in India. The enormous diversification of engines within the different power classes as well as the operation specific requirements regarding various duty cycles, robustness and durability, requires specific solutions to meet these legal limits.
Technical Paper

Servomotor Controlled Standard Automated Manual Transmission for Rapid Smooth Shifts

Present day AMT unit uses two high pressure hydraulically operated pistons for select & shift operations which make the unit weigh around 8kg. Besides this it also makes the unit more complex & unreliable with a lot of torque interruption. The use of electrical servo motors steps in here as a better alternative as it provides a more precise and smoother shift. To test this we used a 5-MT Transmission. For the selection, a precise 14.5 degree of twisting was required which was easily achieved by the servo motor. Further, shift of 10.5mm could be made possible by using the motor to shift the rack using a pinion on the shaft. This system then essentially eliminates the whole hydraulic circuit, the housing of actuator pack & power pack making it a simpler unit all together. Thus, it offers an uninterrupted torque path from the engine to vehicle which allows for a seamless gearshift. This seminal paper provides an introduction to the technology together.
Journal Article

Shifter Fork Stiffness Correlation to Gear Shift Quality

Shift quality of a manual transmission is a critical characteristic that requires utmost care while structuring the transmission. Shift quality is affected by many factors viz. synchronizer design, shifter design, gear design, transmission oil selection etc. This paper presents a correlation between stiffness of the shift fork in manual transmission with the gear shift quality using a gear shift quality assessment setup. Stiffness of shifter fork is optimized using contact pattern analysis and stiffness analysis on MSC Nastran. All the subsystem (i.e. synchronizer and the shift system component) are constrained to optimize the shift fork stiffness. A-5-speed manual transmission is used as an example to illustrate the same. A direct correlation of gear shift fork stiffness with the shift force experienced by the driver is established. The shift system was modeled in the UG NX 6.0 software to collate the synchronization force, shift system gap etc with the constraint on the shift fork.
Technical Paper

Selection of Optimal Design Parameters to Achieve Improved Occupant Performance in Frontal Impacts

Crashworthiness enhancement of vehicle structures is a very challenging task during the early design development process. Major factors influencing occupant injury in frontal impact are vehicle front crush space, crash pulse severity, restraint properties and occupant packaging space. This paper establishes a methodology to define suitable criterion that will guide the designers to select the optimal values of the above mentioned parameters during the early phase of the vehicle development. The usage of lumped mass models, pulse characterization techniques were explored to validate the results. Efficient crash energy management, the concepts of ride down and restraint efficiency parameters were also discussed in the paper.
Technical Paper

C-Shaped Synchronizer Spring-theoretical Analysis and Validation

This paper presents the analysis and experimental validation of c-spring and its stiffness properties in the gear shift synchronizer system. A synchronizer assembly for a transmission comprises of a synchronizer hub carried by a torque delivery shaft and a cone clutch member carried by a gear and a synchronizer blocking ring. The gear shift sleeve is meshing over the teeth of the clutch hub. The c-spring is positioned in the inner circumference of the rim position of the clutch hub and strut keys will be positioned at the slots on the clutch hub, which are usually 120 degree apart. As the sleeve moves while gear shifting, it pushes down the strut keys which compress the C-spring radially inward; this gives the strut load. The strut keys, which are pushed down by the sleeve, will apply force on the c-spring from radial directions. Since the c-spring is in the shape of an arc it is assumed as a curved beam for the analysis.