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In order to meet the challenges of future CAFE regulations & pollutant emission, vehicle fuel efficiency must be improved upon without compromising vehicle performance. Optimization of engine breathing & its impact on vehicle level fuel economy, performance needs balance between conflicting requirements of vehicle Fuel Economy, performance & drivability. In this study a Port Fuel Injection, naturally aspirated small passenger car gasoline engine was selected which was being used in a typical small passenger car. Simulation approach was used to investigate vehicle fuel economy and performance, where-in 1D CFD Engine model was used to investigate and optimize Valve train events (Intake and exhaust valve open and close timings) for best fuel economy. Engine Simulation software is physics based and uses a phenomenological approach 0-D turbulent combustion model to calculate engine performance parameters. Engine simulation model was calibrated within 95% accuracy of test data.

Road Load parameters (rolling resistance and aerodynamic drag) of a vehicle have strong impact on overall Vehicle Emissions and Fuel Economy. The road load coefficients are simulated on chassis dynamometer to carryout emission and fuel economy measurement and are hence required to be found beforehand. A realistic measure of road load parameters can be obtained by conducting a coastdown test. Coastdown test results are hugely impacted by various environmental parameters like ambient temperature, atmospheric pressure, wind speed etc. Though performed in standard boundary conditions, results of multiple tests performed on a vehicle vary from one another due to variations in the mentioned environmental parameters over and above standard test to test variation. This paper aims at studying the variation in test results due to ambient temperature as one of the parameters responsible.

Gearbox power transfer efficiency is a major factor in overall powertrain efficiency of a passenger vehicle. With rapidly changing emission and fuel efficiency regulations, there is a push to increase the gearbox efficiency to improve the overall fuel economy of the vehicle. In case of an existing gearbox, efficiency can be improved by using the low viscosity lubrication oil. Despite a benefit in increasing the gearbox efficiency, lowering down the viscosity of lubrication oil gives rise to few challenges with respect to its performance. One of these challenges is breather performance which defines that transmission oil should not come out of breather pipe in some pre-defined conditions during gearbox operation. As this validation is being carried out on proto parts when the complete system is ready, failure to satisfy the defined criteria for breather performance can lead to multiple trials.

In an automobile, road loads due to tire-road interaction are transferred to vehicle body through suspension. This makes suspension a critical component from the body durability perspective. During vehicle design and development, optimization of suspension parameters to suit ride and handling performance is a continuous and iterative process. These changes on suspension can affect vehicle body durability performance. This paper tries to establish a process to evaluate the effect of changes in suspension parameters on body durability, thus helping in understanding the impact of these changes. The process starts with virtual model building in Multi Body Dynamics software. The base line model is correlated with testing using fatigue at some critical locations on Body in White (BIW).

The fuel efficiency of a vehicle depends on multiple factors such as engine efficiency, type of fuel, aerodynamic drag, and tire friction and vehicle weight. Analysis of weight and functionality was done, to develop a lightweight and low-cost Roof rack rail. The Roof rack rail is made up of a lightweight material with thin cross section and has the design that allows the fitment of luggage carrier or luggage rack on the car roof. In starting this paper describes the design and weight contribution by standard Roof rack rail and its related parts. Secondly, the selection of material within different proposed options studied and a comparison of manufacturing and design-related factors. Thirdly, it has a description of the design of Roof rack rail to accommodate the luggage carrier fitment on the car roof. Moreover, optimizations of Roof rack rail design by continuous change in position, shape, and parts used.

Presently, lot of research is going on, to improve the thermal efficiency and there by the Fuel Economy of vehicles. Increasing the compression ratio to improve on the performance is an option. The compression ratio is a factor that influences the performance characteristics and FE of internal combustion engines. When targeting high output levels at low engine speeds, undesired combustion events called pre-ignition can occur. These pre-ignition events are typically accompanied by very high cylinder peak pressures which can lead to severe damage of engine component. The application engineer needs to optimize this undesired combustion event. This paper describes a systematic application developed to reduce pre-ignition. A case study was done to identify the pre-ignition phenomenon by using in-cylinder measurement. The paper also explains how air, fuel, injection angle and spark can help to avoid pre-ignition.

Over the years, Fuel efficiency and cabin comfort of vehicle has become increasingly important in buying decision and can significantly give competitive edge to the vehicle in marketplace. Weight and friction reduction of rotating and reciprocating components in engines is one of the proven approaches to improve the efficiency of internal combustion engine. To reduce the friction, the general approach is to use low viscosity engine oils, improve the surface finish and reduce the contact area of sliding elements, switch over from sliding contact to rolling contact etc. However sometimes this approach has adverse impact on engine NVH characteristics due to occurrence of abnormal transient noise due to mechanical knocking of the components in specific operating conditions.

Reducing the carbon footprint by meeting stringent emission regulations and improving the fuel efficiency has become an essential feature in 21st century product design cycle for automobiles. Aerodynamic drag affects the fuel efficiency of the vehicle considerably. Various drag reduction devices such as air dam, rim cover, spoiler and undercover etc. are added in order to reduce the drag. This paper aims at understanding the effect of ground clearance on the performance of various aerodynamic drag reduction devices like - air-dam, spoiler, wheel cover and their combinations for hatchback vehicle using Computational Fluid Dynamics (CFD). CFD has been extensively used for exploring the various design configurations and has helped in selecting the optimized aero-parts configuration based on aerodynamic performance at concept stage which has ultimately reduced the vehicle drag coefficient by 10%.