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Technical Paper

Determination of Principal Variables for Prediction of Fuel Economy using Principal Component Analysis

The complexity of Urban driving conditions and the human behavior introduces undesired variabilities while establishing Fuel economy for a vehicle. These variabilities pose a great challenge while trying to determine that single figure for assessment of vehicle’s fuel efficiency on an urban driving cycle. This becomes even more challenging when two or more vehicles are simultaneously evaluated with respect to a reference vehicle. The attempt to fit a generalized linear model, between Fuel Economy as predicted variable and components of a driving cycle as predictor variables produced oxymoronic and counter-institutive results. This is primarily due to existence of multi-collinearity among the predictor variables. The context of the study is to consider the event of driving on a cycle as a random sampling experiment. The outcome of a driving cycle is summarized into a list of predictor variables or components.
Technical Paper

Reduction of Diesel Engine Combustion Noise through Various Injection Strategies

The contribution of engine borne noise is the major source of vehicle noise in diesel powered vehicles. The engine noise can be minimized by modification of engine components design and also with different acoustic abatement techniques. The research activities were carried out on 4-cylinder CRDe engine for SUV application. All the emission and performance parameters along with combustion noise was captured continuously for all the part load points from 1000 RPM to 2750 RPM with respect to the different road conditions and driving cycle. This paper targets on reducing the combustion noise at the noise prone zones only on the basis of the injection strategies ensuring no ill effect on the emissions and fuel economy. The first step was the reduction of rail pressure which helped noise levels to be reduced by almost 6 dB at noise zones. Main injection timing retardation was tried at all possible zones which influenced in considerable noise reduction at various zones.
Technical Paper

Optimization of EGR Mixer to Minimize Thermal Hot Spot on Plastic Duct & Soot Deposition on Throttle Valve Using CFD Simulation

In recent time, with inception of BS VI emission regulation with more focus on fuel economy and emission, many engine parts which were conventionally made from metal are getting replaced with plastic components for reducing weight to attain better fuel economy. EGR is commonly used technique to reduce emissions in diesel engine along with after treatment devices. EGR reduces peak combustion temperature inside the combustion chamber thereby reducing NOx. EGR is bypassed from the exhaust manifold, cooled down in EGR cooler and mixed with intake air at upstream of the intake manifold. Throttle valve is used for controlling the charged air flow to cylinders for different vehicle operating conditions. With compact engine layout EGR mixer are often located near to throttle valve thereby increasing the possibility of soot deposition on throttle valve.
Technical Paper

Evaluation and Selection of Turbocharger Meeting BS6 Emission Norms for 1.99l Engine

Migration to BS6 emission norms from BS4 levels involves strenuous efforts involving advanced technology and higher cost. The challenging part is on achieving the stringent emission norms without compromising the engine fuel economy, performance and NVH factors. Selection of hardware and attaining an optimal behaviour is therefore vital. This article focuses on the evaluation of three different configuration of turbochargers for the same engine to meet the BS6 emission norms and performance. The turbocharger samples used measure the same compressor diameter with varying trim ratios. Simulation and testing of turbochargers ensured positive results for confirmation of the system. Parameters like low speed torque, smoke and compressor efficiency were evaluated and analysed for all configurations. The safe limits of surge and choke regions of all the compressors were also studied and verified.
Technical Paper

Effect of Gear Shift Indicator Technique Enhancing Improved Fuel Economy on SUV

Improving the fuel economy of the vehicle resulting in energy conservation on long run is a challenging task in the automotive field without compromising the emission margins. Fuel economy improvement by effective driving is the main focus of this paper by the proper utilization of gears which can enable good fuel economy even when the vehicle is driven by different drivers. GSI technique was implemented on Sports utility vehicle operating with 2.2 l engine. Tests were carried with GSI and the effect of fuel consumption and emissions were compared to the regular driving cycle. Optimization of various gear shifting points were analyzed and implemented for better fuel economy keeping the drivability in mind, meeting the BS4 emission norms comfortably. The experiments were carried out in both cold and hot conditions to check the effect of GSI and positive results of fuel economy improvement was yielded.
Technical Paper

Comparative Studies of Different VGT Designs on Performance and Smoke of CRDe Engine

Diesel engines have occupied a significant position in passenger car applications in the present automotive sector. Turbochargers find a very prominent role in diesel engines of all applications in order to achieve desired power and better fuel economy. Gaining higher torque at lower engine speeds with low smoke levels is a very tough task with fixed geometry turbochargers due to availability of lower air mass resulting in higher smoke emissions. Variable geometry turbochargers are capable of providing better torque at lower speeds and reduced smoke emissions on Common Rail Diesel engines. The Variable Geometry Turbocharger types used in this study are straight profile nozzle vanes (sample A) and curved profile nozzle vanes (sample B). The curved profile vanes as seen in sample B results in reduced variation of circumferential pressure distortions.
Technical Paper

Methodological Approach for Matching Gear and Final Drive Ratio for Better Fuel Economy, Performance and Drivability

Fuel economy, performance and drivability are the three important parameters for evaluating the vehicle performance. Powertrain matching plays a major role in meeting the above targets. Fuel economy is measured based on city, highway and some user defined driving cycles which can be considered as real world usage profiles. Performance and Drivability is evaluated based on the in-gear, thru-gear (acceleration performance) and grade-ability performance. The load collective points of the engine greatly influence the engines performance, fuel economy and emissions, which in-turn depends on the N/V ratio of the vehicle. The optimal selection of gear and final drive ratios plays a key role in the optimization of the Powertrain for a particular vehicle. The current study involves dynamic simulation of the vehicle performance and fuel economy at transient engine test-bed for different gear and final drive ratio combinations using AVL DynoExcat-dynamometer.
Technical Paper

Novel Approaches for Model-Based Development - Part I: Developing a Real-World Driver Model

OEMs these days are focusing on front loading the activities to Virtual Test Environment (VTE) based development owing to high development cost and complexity in achieving repeatability during testing phase of vehicle development,. This process not only helps in reducing the cost and time but also helps in increasing the maturity and confidence level of the developed system before actual prototype is built. In the past, extensive research has happened for increasing the fidelity of VTE by improving plant model efficacy which involves powertrain and other vehicle systems. On the other hand, improving the precision of driver model which is one of the most complex nonlinear systems of virtual environment still remains a challenge. It is apparent that various drivers show different behavior in real world for a given drive profile. While modelling a driver for a VTE, the real world driver attributes are seldom considered.
Technical Paper

Cost and Weight Efficient Differential Housing for Off-Road Vehicles

Differential in Gear Box play vital role in Tractors for assisting it in turning and also to take straight path. Light weight machine always have advantage in terms of fuel economy and performance. Weight optimized rotating part have additional benefits of saving power loss, against stationary dead weight. Differential Housing is such a part, which rotates during the vehicle motion and torque transmission. [1] This paper describes a method by which weight of the Differential Housing is optimized. In this particular body of work, additional constraints of avoiding any change in existing cold forged parts like Bevel Gear & Pinion. This also have additional benefit of enhanced flow of Oil inside Differential Housing for better lubrication of Bevel Gears and Pinion. This resulted in weight saving of Differential Housing and finally fuel economy of Tractor.
Technical Paper

Factors affecting Regeneration interval of a Diesel Particulate Filter and their influence on BSV emission application

With the implementation of stringent PM emission norms in various countries for diesel vehicles, the legislation demands a PM mass limit as low as 4.5mg/km in the NEDC cycle, starting from Euro5. This makes the usage of Diesel Particulate Filters (DPF) mandatory. The same is going to be mandated for upcoming BSV emission norms in India. Thus it becomes imperative to know the functional aspects of a DPF and their impacts. Basically there are two major functions of a DPF- Soot mass filtration and Soot burning or Regeneration. This paper highlights usage of DPF in Indian context from the perspective of one of the major aspects of DPF regeneration-Regeneration Interval, which is basically governed by vehicle/engine out smoke. Regeneration interval also has direct or indirect influence on life of engine of a vehicle and average fuel economy of a vehicle which will also be touched upon herein.