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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 today’s Indian automotive industry, vehicles are becoming more complex and require more efforts to develop. Also, new and upcoming regulations demand more trials under varied driving conditions to ensuring robustness of emission control. Combined with expectations of customer to get new products more frequently, requires solutions and methods that can allow more trials with required accuracy to ensure compliance to stricter regulation and delivery a quality product. This translates into more trials in less time during the development life cycle. Recently, to overcome above challenge, there has been focus on simulating the vehicles trials in engine bench environment. ‘Road to Lab to Math’ (RLM) is a methodology to reduce the effort of On-road testing and replace it with laboratory testing and mathematical models. Also, on-road testing of prototype vehicles is expensive as it requires physical parts.

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.

Valve train system is one major contributor to engine overall friction loss and is approximately 30% of total engine friction at lower speed and approximately 20 % at higher engine speed. Valve spring loads (preload and working) are proportional to friction loss of valve train. To optimizing the valve spring design main requirement is valve train perform it function safely at maximum engine cutoff RPM with minimum preload and working load. Robustness and frictional power loss are contradicting requirement, robustness demand high stiffness spring for better valve jump and bounce performance with dynamic safe valve spring design, on the other hand low frictional power loss demand for use of low stiffness spring. To optimize the valve spring stiffness for meeting both the requirement we need accurate prediction of valve spring in design stage and good correlation with testing data to reduce the number of iterations.

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 view of global concern for greenhouse gas emissions, need for greener and efficient Engines is increasing. Hence is it imperative that Internal Combustion Engines are improved in terms of efficiency to reduce Greenhouse gas emissions and meet CAFE targets. The cooling system of an ICE plays a major role in a vehicle performance. In this system, the radiator, thermostat, and cooling fan are the main components. Conventional cooling system uses Wax-type thermostat which is activated at specified coolant temperature and maintain same coolant temperature in fully warmed up condition at all engine operating points. Operative temperature selection in Wax-type is trade-off between engine friction & thermal efficiency at lower loads & knocking at higher loads. An electronic thermostat is a good alternative to maintain optimum temperature as per operating point requirement since optimum temperature at different operating points can be different.

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.

With strict upcoming regulation norms, it becomes a challenging task for automotive industry to develop highly efficient engine that meets all the regulation requirements. The focus of automakers is to utilize fuel energy in most efficient way and to reduce the energy loss from the engine to improve thermal efficiency. Heat loss to the cooling medium is one of the prime losses inside the combustion chamber. Thermal barrier coating is used to reduce heat losses across combustion chamber surfaces (Piston, head, valves and cylinder liner) as it provides good insulation because of the prominent properties of coating materials like low thermal conductivity, low heat capacity, high melting point etc. This paper presents application and impact of thermal swing coating on thermal efficiency. Thermal swing coating material follows gas temperature quickly throughout the cycle which reduces the temperature difference between gas and coating surface and thus reduces the heat loss.

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.

Blending locally produced ethanol with petrol will help India strengthen its energy security. India is making steady progress in raising the share of ethanol having increased to 8.1% in ethanol supply year 2020-21 (Dec-Nov) with target to achieve 10% ethanol blending in the ethanol supply year 2021-22. In future, Government of India is planning to start supply of 20% ethanol blended petrol from Apr’23 and to cover PAN India by Apr’25. Pure ethanol has lower calorific value than Petrol thus ethanol blended petrol will always have calorific value lower than that of petrol thereby deteriorating Fuel economy. On the other hand, ethanol blended petrol will have higher RON compared to petrol. Higher RON reduces knocking tendency thereby providing calibration optimization potential to optimize Spark timing. Optimized spark timing can help in improving Full Load Torque by reducing Phasing losses and operating closer to MBT.

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%.