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Technical Paper

A Holistic Approach to Develop a Modern High Power Density Diesel Engine to Meet Best-in-class NVH levels.

2020-04-14
2020-01-0406
The ever-increasing customer expectations put a lot of pressure on car manufacturers to constantly reduce the noise, vibration and harshness (NVH) levels. This papers presents the holistic approach used to achieve best-in-class NVH levels in a modern high-power density 1.5 lit 4 cylinder diesel engine. The base engine architecture was designed with NVH reduction features such as crank-offset, cast iron crankcase, stiffened ladder frame, structural oil pan and front cover. Piston skirt profile was optimized to reduce the slapping noise by carefully studying the secondary motion and skirt contact pressure. The plastic parts such as cylinder head cover and intake manifold were designed with closely spaced ribs and high wall thickness. Natural frequency targets for different parts were set for the entire engine at component level and system level and confirmed through simulations.
Technical Paper

Robust and optimum design selection for crank train dampers

2020-04-14
2020-01-0603
Reduced engine noise and vibrations is a key challenge in product development which leads to better comfort for end customer. Cranktrain is a major contributor in the transfer path of gas oscillations. The noise and vibrations induced by cranktrain torsional resonances are reduced by providing torsional dampers. Dampers are also important for avoiding resonant failures. The requirements from dampers is high reliability, lesser sensitivity for manufacturing variability in rubber properties with respect to desired performance. The requirement from a cranktrain damper is to achieve minimum crankshaft vibratory torque. Also, damper heat dissipation and torsional oscillations need to be within acceptable limits. This depends on selection of damper dimensions, damper hub inertia, ring inertia and rubber stiffness. There is a non-linear dependence of these parameters on damper performance. Hence, it needs an optimizer with better design space exploration capabilities.
Technical Paper

EGR flow control strategy for a smaller capacity diesel engine using a phase shifting chamber

2020-04-14
2020-01-1358
Exhaust gas recirculation (EGR) is an effective strategy to control NOx emissions in diesel engines. EGR reduces NOx through lowering the oxygen concentration in the combustion chamber, as well as through heat absorption. The stringent emission norms have forced diesel engines to further improve thermal efficiency and reduce nitrogen oxides (NOx). Throttle control is adopted in diesel intake system to control the EGR & fresh charge flow and to meet the emissions norms. In three or lesser cylinder. diesel engines, predominantly single and two-cylinder diesel engines, there is a higher possibility of the exhaust gas reaching the intake throttle and Particulate matter getting deposited on the throttle body. This can significantly affect the idling stability and intake restriction in prolonged usage. In idling condition, the clogged throttle body stagnates the fresh charge from entering the cylinder. The work aims at the study of flow pattern for EGR reaching the throttle body.
Technical Paper

Effect of Flange radius and width on the Fatigue Life of wheel hub under Cornering Loads

2020-04-14
2020-01-1232
Automotive Wheel Hub is a safety critical component. Integrated Wheel hub design is improved from 1st generation to 3rd generation to meet the durability targets with less weight. Lateral loading is critical parameter for designing wheel hub. Cornering test is performed at vehicle level to evaluate wheel hub. Cornering test has combination of three types of tracks. In Wheel hub design, flange radius and flange width are two important design parameters to meet the durability life for cornering loads. We have considered the combination of different flange radius and flange width to understand the effect of these two parameters on wheel hub fatigue life. These three-wheel hubs are tested till failure and life scatter is plotted. Strain data is acquired at flange radius on wheel hub for all cornering test tracks. Using Wheel Force Transducers (WFT), Forces and moments are acquired at wheel center for all cornering test tracks. Duty cycle is derived from measured loads.
Technical Paper

Using Vehicle Specifications to Gain Insights into Different Automotive Market Requirements

2020-04-14
2020-01-1283
Determination of vehicle specifications (for example, powertrain sizing) is one of the fundamental steps in any new vehicle development process. The vehicle system engineer needs to select an optimum match of vehicle, engine and transmission based on the product requirements received from Product Planning (PP) and Marketing teams during concept phase of any vehicle program. This process is generally iterative and requires subject matter expertise. For example, accurate prediction of powertrain sizing is essential to meet the required fuel economy (FE), performance and emission targets for different vehicle configurations. This paper analyzes vehicle specifications of existing fleet (Passenger Cars/SUV, Gasoline/Diesel) in different automotive markets (India, Europe, US, Japan) and aims to determine underlying trends across them.
Technical Paper

Gear Shift Pattern Optimization for Best Fuel Economy, Performance and Emissions

2020-04-14
2020-01-1280
FTP-75 drive cycle does not have a prescribed gear shift pattern and automotive OEM has the flexibility to decide. Conventionally the gear shift pattern was arrived at based on trial and error method typically in 10 to 12 Iterations on chassis dynamometer. It was a time consuming (i.e. ~ 3 to 4 months) and costly process. This approach also led to poor fuel economy (FE) labeling declaration. A simulation procedure needed to be established in such cases to generate a gear shift pattern that gives optimal trade-off amongst conflicting objectives (FE, Performance and Emissions). A simulation tool was developed in MATLAB to generate an optimum gear shift pattern. 3 different SUV/UV models were used as test vehicles in this study. Chassis dyno testing was carried out and data was collected using the base and optimized gear shift patterns. Dyno test results with optimized gear shift pattern showed FE improvement of ~ 4 to 5% while retaining the NOx margin well above engineering targets.
Technical Paper

Thermodynamic Analysis of Turbocharger for a High Power Density Diesel Engine

2019-01-09
2019-26-0051
Passenger cars claim their presence in market by its pick up, top speed and maximum power of the engine. The study described in this paper is focused on improving the low-end performance of a 4-cylinder 1.6 L diesel engine while meeting the targeted maximum power. To meet the cause turbocharger works as an important element of the engine. A comparative study between regulated two stage turbocharger (R2S) and variable geometry turbocharger (VGT) shows that on a 4-cylinder engine VGT is superior by providing higher boost at 1000 engine rpm full load, than R2S, while in 3-cylinder (same displacement) the opposite effect can be seen. After simulations and iterations, it was confirmed that the in 4-cylinder the exhaust pulse cancellation were leading to a lesser exhaust energy at the turbine inlet. This pulse interaction leads to higher residual gas content which affects the low-end performance.
Technical Paper

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

2019-01-09
2019-26-0359
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

Development of Low Cost FEAD System with Stretch Fit Belt

2018-07-09
2018-28-0064
In Current scenario all Vehicle Manufacturer are looking towards cost effectiveness in their product development without compromising product quality and performance. With this reference, development of low cost FEAD (Front End Accessory Drive) system with stretch fit belt & idlers for multiple accessories has emerged as one of the alternative smart engineering solution against the FEAD with auto tensioner. The beauty of this low cost FEAD system is not only the cost saving but also the long lasting performance without affecting component life. In the current work, development of a low cost FEAD for 3 cylinder 1.5 litre diesel engine has been presented. It was one of the challenges to introduce stretch fit belt for 3 cylinder engine considering the high torsional vibration. The performance of this FEAD system was evaluated in terms of accessories pulley slip and belt flapping. The component durability was assessed both at engine as well as at vehicle level.
Technical Paper

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

2018-07-09
2018-28-0074
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

Optimization of Oil Separation Unit for Two Stage Turbocharged Engine

2018-07-09
2018-28-0066
In addition to performance target, recent stringent emission legislation and reduction in oil consumption are the major driving force for engine design and development. In this reference importance of crankcase ventilation has increased immensely and the manufacturers are bound to develop most efficient system with high oil trap efficiency. In crankcase ventilation system, the blow-by gases from the crankcase are routed to the intake manifold through Oil separator system. The oil separator task is to retain the oil part from the blow by gas and send it back to sump. Developing an oil separator for the engine studied here was very challenging considering double stage turbocharger which produces very fine mist of oil and is difficult to separate. The study shows that oil mist coming in blow by is of size 0.3 micron and lesser than it. The major contribution of these fine mists was from turbocharger.
Technical Paper

Low Rolling Resistance Tires and Their Impact on Electric Vehicles

2017-07-10
2017-28-1941
This paper details the methodology used to show the importance of Low rolling resistance tires in Electric Vehicles. Fuel efficiency and range is paramount with most of the electric vehicle buyers. Although many people are now becoming aware of low rolling resistance tires but its development started way back in 1990’s. It is always challenging to achieve low rolling resistance in smaller tires of size 12 inch or 13 inch along meeting the other critical vehicle parameters such as ride and handling, NVH, durability and many more. The reduction in rolling resistance can also affect the traction properties of tires. In case of very low rolling resistance tires the traction will be very less but it can badly affect the other vehicle parameters. Selection of tires further depend upon the RWUP (Real World Usage Profile). It means the vehicle is targeted for which region and what is the condition of roads there.
Technical Paper

Assessment of Cabin Leakage on Thermal Comfort and Fuel Efficiency of an SUV

2016-04-05
2016-01-0259
The main function of an air conditioning system in a vehicle is to provide the thermal comfort to the occupant at minimum possible energy consumption in all environmental conditions. To ensure the best possible thermal comfort, air conditioning system is optimized on various parameters like heat load, air flow distribution, glass area, trim quality, insulations and cabin leak rate. A minimum cabin leakage is regulatory requirements to ensure the air quality of cabin. Anything above the minimum cabin leak rate ultimately turn into reduced thermal comfort and additional energy consumption. The additional energy consumption to maintain the required thermal comfort in the cabin due to cabin leakage affects the fuel efficiency severely. In the present study, the effect of cabin leakage on fuel efficiency and thermal comfort is studied in details by varying the cabin leakage through mechanical means. The experiments are carried out in normal environmental condition and road condition.
Technical Paper

Cost and Weight Efficient Differential Housing for Off-Road Vehicles

2016-02-01
2016-28-0133
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

Optimization of Vehicle Electrical Energy Consumption

2015-09-29
2015-01-2882
This paper focuses on optimizing the electrical energy consumption of vehicle. By introduction three concepts. 1) Innovative speed control logic for radiator fan motor according to vehicle speed and air flow through radiator. 2) Introducing regeneration of energy from radiator fan motor while free running and deceleration of vehicle. 3) Using BLDC motors (generation mode and motoring mode) in radiator and blower motors. About 50 % of total electrical energy consumption of vehicle is contributed by radiator fan motor and blower motor (proven data by performing alternator charge balance test during NEDC cycle). By introducing above three concepts, 50 % electrical energy consumption can be reduced to 25 - 30 %, which gives more than 3.5 % fuel economy improvement and more than 10 gmCO2 reduction per kilometer. Further reduction in conducted emission at motor level, soft starting for radiator fan and blower motor and elimination of high inrush current.
Technical Paper

Sealing Prediction and Improvement at Cylinder Head & Block Interface under Thermo-Mechanical Loading involving Multi- Layer Steel Gasket

2015-04-14
2015-01-1743
An inadequate sealing of the combustion chamber gasket interface may have severe consequences on both the performance & emission of an engine. In this investigation, both the distribution of the contact pressure on the gasket and the stresses of the cylinder head at different loading conditions are explored and improved by modifying the design. A single cylinder gasoline engine cylinder head assembly has been analyzed by means of an uncoupled FEM simulation to find the sealing pressure of the multi-layer steel (MLS) gasket, strength & deformation of the components involved. The thermal loads are computed separately from CFD simulations of cylinder head assembly. The cylinder head assembly consisting of head, blocks, liner, cam shaft holder, bolts, gaskets, valve guides & valve seats, is one of the most complicated sub-assembly of an IC engine.
Journal Article

An Experimental Study of Turbocharged Hydrogen Fuelled Internal Combustion Engine

2015-01-14
2015-26-0051
Hydrogen is considered as one of the potential alternate fuel and when compared to other alternate fuels like CNG, LPG, Ethanol etc., it has unique properties due to absence of carbon. In the current work, Hydrogen engine of 2.5 L, four cylinder, spark ignited Turbocharged-Intercooled engine is developed for Mini Bus application. Multi-point fuel injection system is used for injecting the hydrogen in the intake manifold. Initially, boost simulation is performed to select the optimum compression ratio and turbocharger. The literature review has shown that in-order to get the minimum NOx emissions Hydrogen engines must be operated between equivalence ratios ranging from 0.5 to 0.6. In the present study, full throttle performance is conducted mainly with the above equivalence ratio range with minimum advance for Maximum Brake Torque (MBT) ignition timing. At each operating point, the performance, emissions and combustion parameters are recorded and analyzed in detail.
Technical Paper

Computational and Experimental Investigations to Improve Performance, Emissions and Fuel Efficiency of a Single Cylinder Diesel Engine

2015-01-14
2015-26-0099
From International Energy Statistics (IES) survey, China, US and India are top three countries in emitting CO2 emissions. Further, worldwide national governments are focused to control CO2 emissions at source by stringent regulatory limits. OEMs and Research laboratories are working on several technology options such as advanced fuel injection system, optimizing in cylinder combustion system, thermal management and reduced engine friction to meet this legal requirements. In this paper, research work focused on improving combustion system through selection optimum bowl geometry and increasing volumetric efficiency through valve timings, profile and intake system using both 1D and 3D-CFD numerical approach. The main objective of this approach to utilize fossil fuel to its maximum potential in a single cylinder Naturally Aspirated (NA) water cooled engine with CRDI.
Technical Paper

Positive Difflock Stopper for Off Road Vehicles

2015-01-14
2015-26-0143
The purpose of a differential is to allow the wheels of an automobile to turn at different speeds so that it does not skid during turning. However when a vehicle runs on a slick or muddy surface (especially in Agricultural and constructional Field applications) that same feature causes the wheel with less traction to spin freely as this unit transmits power to the tire with least amount of traction. The function of a difflock is to lock the differential gears, by locking the differential, both the axles receive equal power and hence equal traction is available at both the tires. This Paper describes the positive locking of a differential by stopper, and also in detail the problems associated with its engagement and disengagement in tractors and construction equipment's. Additionally a concept for a difflock stopper which has been experimentally proven for tractors and construction equipment's is also discussed.
Technical Paper

Systematic Approach to Design Hand Controlled Parking Brake System for Passenger Car

2015-01-14
2015-26-0078
This paper is an attempt to compile a systematic approach which can be easily incorporated in the product development system used in the design and development of parking brake systems for passenger cars having rear drum brakes, which in turn can effectively reduce the lead time and give improved performance. The vehicle GVW, percentage gradient and maximum effort limits (as per IS 11852 - Part 3), tire and drum brake specifications were taken as front loading. This data is used for target setting of functional and engineering parameters, such as lever pull effort, lever ratio and angular travel of lever. Design calculations were performed to obtain theoretical values of critical parameters like lever effort and travel. The comparison between target and theoretical values give the initial confidence to the system engineer. Further, the outcome was taken to conceptualize the hard points of lever on vehicle for ergonomics.
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