Effective cooling of a heated brake system is critical for vehicle safety and reliability. While some flow devices can redirect airflow more favorably for convective cooling, such a change typically accompanies side effects, such as increased aerodynamic drag and inferior control of brake dust particles. The former is critical for fuel efficiency while the latter for vehicle’s soiling and corrosion as well as non-exhaust emissions. These competing objectives are assessed in this study based on the numerical simulations of an installed brake system under driving conditions. The thermal behavior of the brake system as well as aerodynamic impact and brake dust particle deposition on areas of interest are solved using a coupled 3D transient flow solver, PowerFLOW. Typical design considerations related to enhanced brake cooling, such as cooling duct, wheel deflector, and brake air deflector, are characterized to evaluate the thermal, aerodynamic and soiling performance targets.
This report summarizes initial results and findings of a model developed to determine the braking performance of commercial motor vehicles in motion regardless of brake type or gross weight. Real-world data collected by Oak Ridge National Laboratory for a U.S. Department of Energy study was used to validate the model. Expanding on previous proof-of-concept research showing the linear relationship of brake application pressure and deceleration additional parameters such as elevation were added to the model. Outputs from the model consist of coefficients calculated for every constant pressure braking event from a vehicle that can be used to calculate a deceleration and thus compute a stopping distance for a given scenario. Using brake application pressure profiles derived from the dataset, stopping distances for light and heavy loads of the same vehicle were compared for various speed and road grades.
The most appreciated driving characteristics of electric vehicles are the quietness and spontaneous torque rise of the powertrain. The application of range extenders (REX) with internal combustion engines (ICEs) to increase the driving range is a favourable solution regarding costs and weight, especially in comparison with larger battery capacities. However, the NVH integration of a REX is challenging, if the generally silent driving characteristics of electric vehicles shall remain preserved. This paper analyses key NVH aspects for a REX design and integration to fulfil the high expectations regarding noise and vibration comfort in an electric vehicle environment. The ICE for a REX is typically dimensioned for lower power outputs, incorporating a low number of cylinder units, which is even more challenging concerning the NVH integration. The basic REX concept is evaluated by considering power and fuel efficiency demands in combination with an interior noise forecast.
As a common means for reducing vibration and noise for automobiles, damping material is usually employed in the vehicle body, typically on the floor, the dashboard, and the top roof. With the growing demand of fuel economy, light weighting, as well as NVH comfort, the optimization of the damping pads has become a topic of increasing importance. In numerical simulation, the traditional methods generally make use of the modal strain energy of the metal sheet as the main indicator for making layout choice for the damping pads. The optimization is not performed according the vehicle’s real working condition. Furthermore, the traditional methods do not depend on the accurate properties of the damping material. In this paper, a novel optimization method based on energy analysis is presented.
Diesel engines have been widely popularized as a power source for vehicles because of its reliable horsepower and excellent fuel economy. Diesel engines are considered as one of the dangerous sources of pollution. PM and NOx are the dominant pollutants emitting in exhaust gases. As per the supreme court order, Indian market will see only the sale of Bharat Stage-VI vehicles from April 1, 2020. More stringent NOx standards in BS-VI legislation for heavy duty vehicles would help to reduce NOx emission around 88.57% and 86.85% for steady and transient test cycles respectively. Urea SCR technology is used for reduction of NOx level. SCR is a media of converting NOx into diatomic nitrogen and water with the aid of Cu-Zeolite catalyst. Aqueous urea named as DEF is used as reductant which is added in a stream of exhaust gases. This experimental study focuses on performance evaluation of urea-SCR system in heavy duty vehicle.
To tackle the problem arising due to emissions and to reduce them, complex after-treatment system is used. For efficient working of the after treatment system it must operate at sufficient high temperature even at low loads for better conversion efficiency. Also, there is different temperature requirements for different catalyst used in SCR (Selective catalyst reduction) system. For this, various on engine strategies are implemented on modern diesel engines such as multiple fuel injection, late fuel injection, high injection pressure and exhaust gas recirculation. Thermal management is an operating condition which must be triggered when there is need of elevated temperatures for efficient functioning of the after treatment system. Thermal management includes SCR thermal management and regeneration. The process of removing deposits from after treatment system is known as regeneration.
It is imperative that all the automobile manufactures conduct vehicle level benchmarking at the initial stage of any new project. From the benchmark information, the manufacturers can set relevant targets for their own vehicle under development. In this regard, an accurate prediction of the engine operating points can improve the correlation of the measured fuel economy of the benchmark vehicle. The present work describes a novel method which can be used for the accurate prediction of the engine operating points of any benchmark vehicle. Since the idea of instrumenting the crankshaft / driveshaft with torque transducers is a costlier and time-consuming process, the proposed method can be effective in reducing the benchmarking.
With the increasing adoption of electric vehicle in India, autos are also getting in the electrification race with lighter lithium-ion batteries and motor replacing the bulkier engine and transmission. This trend has to lead to a lighter vehicle which in-turn gives better mileage figure but at the loss of dynamic stability of the vehicle making them very unsafe. The current auto-rickshaws are using delta configuration wheel geometry which in turn are more prone to the rollover while cornering. The three-wheeled configuration vehicle is less dynamically stable than the normal four-wheeled configurations. While working for on prototype vehicle for Shell Eco-Marathon Asia pro and cons for both configurations for a three-wheeled vehicle was considered and tadpole configuration was found to be more stable and better than current delta configuration.
Automakers are being subjected to increasingly strict fuel economy requirements which led OEMs to focus more on Light weighting and Energy efficiency areas. Considering the aforesaid challenges, efforts has been taken in Light weighting of Mounting bracket for Engine application. This paper deals with conversion of Engine accessory bracket from Aluminium material to Metal Matrix composite (MMC). In Design phase, existing bracket has been studied for its structural requirements and further Bracket is designed to meet MMC process requirement and CAE carried out for topology optimization and Structural integrity. In Validation phase, Component is Validated at Test bed and Vehicle level for its reliability and durability. Finally observations and results were compared for Existing design and Proposed design and further optimization proposed.
Vehicles with manual transmission are still the most preferred choice in emerging markets like India due to their benefits in cost, simplicity and fuel economy. However, the ever-increasing vehicle population and traffic congestion demand a smooth clutch operation and a comfortable launch behaviour of any manual transmission vehicle. In the present work, the launch performance of a sports-utility vehicle (SUV) equipped with dual mass flywheel (DMF) and self-adjusting technology (SAT) clutch could be improved significantly by optimizing the clutch system. The vehicle was observed to be having a mild judder during clutch release (with 0% accelerator pedal input) in normal 1st gear launch in flat road conditions. An extensive experimental measurement at the vehicle level could reveal the launch judder is mainly due to the 1st order excitation forces created by the geometrical inaccuracy of the internal parts of the clutch system.
The present numerical analysis aims at studying the effect of changes in profile of truck-trailer on aerodynamic drag and its adverse effect on fuel consumption. The numerical analysis is carried out using commercial CFD software, ANSYS Fluent, with k-ω Shear tress transportation (SST) turbulence model. In present study four models of truck were analyzed, including baseline model at different Reynolds numbers, namely 0.5, 1, 1.5 and 2 millions. In order to enhance fuel consumption, various profile modifications have been adapted on baseline truck-trailer model by adding a spoiler and bottom diffuser at the rear of the truck, by providing vortex generator at the rear top of the truck and by adding boat tail at the end of trailer. The comparison has been done with respect to coefficient of drag, coefficient of pressure, pressure contours, and velocity vectors between all four cases.
This investigation is based on the development of internal combustion engine and focusing on retaining the two-stroke cycle engine with sophisticated technologies. Due to stringent emission norms, faster depletion of petroleum fuels, fuel economy this modification is suggested based on the critical analysis. The development of a supercharged cross breed engine will be a next milestone in automotive fields, which will enhance the upcoming I.C. engines to work under effective efficiency without any deviations from the actual working cycle. The design and simulation have been carried to out to reduce or eliminate the losses during operation. Also,both the power and emission characteristics of a engine were balanced and improved than the conventional engines.
Natural gas has been used in spark-ignition (SI) engines of natural gas vehicles (NGVs) due to its resource availability and stable price compared to gasoline. It has the potential to reduce carbon monoxide emissions from the SI engines due to its high hydrogen-to-carbon ratio. However, short running distance is an issue of the NGVs. In this work, methodologies to improve the fuel economy of a commercial heavy-duty truck under the Japanese Heavy-Duty Driving Cycle (JE05) is proposed by numerical 1D-CFD modeling. The main objective is a comparative analysis to find an optimal fuel economy under three variable mechanisms, variable valve timing (VVT), variable valve actuation (VVA), and variable compression ratio (VCR). Experimental data are taken from a six-cylinder turbocharged SI engine fueled by city gas 13A. The 9.83 L production engine is a CR11 type with a multi-point injection system operated under a stoichiometric mixture.
Due to CAFÉ regulations and advanced emission regulations for Indian auto industry, fuel efficiency gain via lower viscosity lubricants is a trend in auto industry. Achieving fuel economy by reducing oil viscosity is already established for passenger car motor oils (PCMOs) but is in its initial phase for heavy-duty diesel engine oils (HDDEOs). Now SAE 15W-40 is the most widely used viscosity grade by volume for HDDEO. Again the emission norms and CAFÉ regulations are applicable for new engines whereas a large population of vehicles in India is old vehicles meeting BS II, BS III and BS IV norms. It is also important to reduce fuel consumption in those vehicles to help in the reduction of GHG emissions. In this paper, the authors discuss the development of a low viscosity heavy duty diesel engine oil in 10W30 viscometrics meeting API CH4 specification.
Fuel economy is an integral indicator of the efficiency of cars, trucks and buses. The fuel consumption of the car can vary several times in different driving conditions. In work the analysis of the factors influencing fuel consumption of the car is carried out. The main parameters characterizing the operating conditions are determined. All operating conditions are divided into road, transport and atmospheric-climatic conditions. A mathematical model is proposed for calculating the fuel consumption of vehicles, which takes into account the design parameters, speed, loading, operating conditions. The peculiarity of the calculation method is the use of an analysis of the energy necessary for movement under certain conditions. Evaluation of the efficiency of the condition and functioning of the machines was carried out according to the coefficient efficiency of the car.
Internal Combustion engines have been a significant component of the industrial development in the 20th and 21st centuries. However, the high working temperatures cause extensive wear and tear among the parts and results in a loss in fuel efficiency and ultimately seizes the engine. To prevent this, there was a need for a cooling system. The current systems cool the vehicle's engine by transferring heat from the engine to the coolant /water in the water jacket from where it reaches the radiator via tubes, and the hot temperature coolant is cooled. This article proposes a change in the design of radiator fins to improve the overall cooling efficiency of such systems. As radiator fins are instrumental in the heat transfer process, a design change in them results in substantial changes in the output efficiency results. The central concept that is utilized is to increase the surface area of the fins, which would increase the rate of heat loss from the pipes.