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Technical Paper

A Secondary De-Aeration Circuit for an Engine Cooling System with Atmospheric Recovery Bottle to Improve De-Aeration

2014-09-30
2014-01-2342
In any engine cooling system, de-aeration capability of the system plays a very critical role to avoid over heating of an engine. In general, with recovery bottle engine cooling system there is one vent hose from radiator pressure cap to the recovery bottle and coolant in the bottle is exposed to atmospheric pressure. From this vent hose air bubbles will move to recovery bottle from the engine and radiator when pressure in the system exceeds pressure cap setting. With this arrangement, de-aeration from the engine will happen when thermostat opens only and till that time air bubbles will be in the engine only and in this time there will be chance of overheating at some critical conditions because of air pockets in to the engine water jacket and the entrained air in the cooling circuit. Also, secondly 100 % initial filling cannot be achieved.
Technical Paper

Aerodynamic Drag Reduction of an Intercity Bus through Surface Modifications - A Numerical Simulation

2019-10-11
2019-28-0045
The maximum power produced by the Engine is utilized in overcoming the Aerodynamic resistance while the remaining has been used to overcome rolling and climbing resistance. Increasing emission and performance demands paves way for advanced technologies to improve fuel efficiency. One such way of increasing the fuel efficiency is to reduce the aerodynamic drag of the vehicle. Buses emerged as the common choice of transport for people in India. By improving the aerodynamic drag of the Buses, the diesel consumption of a vehicle can be reduced by nearly about 10% without any upgradation of the existing engine. Though 60 to 70 % of pressure loads act on the frontal surface area of the buses, the most common techniques of reducing the drag in buses includes streamlining of the surfaces, minimizing underbody losses, reduced frontal area, pressure difference between the front & rear area and minimizing of flow separation & wake regions.
Technical Paper

Agricultural Tractor Hydraulic Lift Arm Assembly Design for Durability and Correlation with Physical Test

2016-02-01
2016-28-0237
A hydraulic power train assembly of an agricultural tractor is meant to lift the heavy implements during field operations and transportation. As it is a crucial member of the tractor for its usage, so the power train assembly needs a properly designed lift arm, rocker arm assembly with better strength and stiffness. There are a standard like IS12224, IS4468 which regulates the test method for hydraulic power and lift capacity of tractor and the layout of hydraulic three point linkage. Computer aided engineering techniques followed by laboratory testing have been deployed in the earlier stages of the product design & development itself to deliver the first time right products to the customer. In this paper, a virtual simulation process has been established to design an agricultural tractor hydraulic lift arm to meet the above requirements. A Design Verification Plan (DVP) has been developed consisting of 3 load cases.
Technical Paper

Analytical Method to Determine Press-fit Tolerance between Torque Carrying Members

2012-09-24
2012-01-1996
This paper deals with an analytical method to calculate the press-fit tolerance and fits between gears and shaft for automotive applications. The relative interferences increase sharply in the small diameter range, therefore one must be especially careful when designing small diameter joints. The strength of press-fit depends on the amount of relative interference; extreme interference leads to excessive contact stresses between the gear and shaft eventually leading to failure. Too little interference leads to slippage of gear on the shaft. In the press fit connection a shaft's spline rolling operation and gear internal broaching is eliminated. It is more economical than a conventional spline connection. Press fit connections are used in various transmission between a shaft and a gear. They are used in 6 speed transmission to 9-speed transmission for (German based Vehicle Manufacturer) heavy and light commercial vehicle company.
Technical Paper

Approach to Estimate Life of Li-Ion Power Battery for Mild Hybrid Application in India

2015-04-14
2015-01-0249
Development of Hybrid Electric Vehicles (HEVs) and Battery Electric Vehicles (BEVs) is gaining traction across all geographies to help meet increasing fuel economy regulations and as a pathway to offset concerns due to climate change. But HEVs and EVs have so far been a nascent market for India. These technologies have primarily shifted towards Lithium-ion batteries (LIB) for energy storage due to its high energy and power densities. In order to make actual business sense of these technologies, of which, battery is a major cost driver, it is necessary for these batteries to provide similar performance and life expectancy across the operating boundary of the vehicles, as well as provide the requirements at a competitive cost. In other words, the LIBs have to sustain the normal life cycle requirements and withstand wide range of storage temperatures that the conventional gasoline/diesel vehicles have been good at and still ensure good life.
Journal Article

Design and Development of Electro Hydraulics Hitch Control for Agricultural Tractor

2017-01-10
2017-26-0227
Tractor hitch control system is used for attaching and operating various Agricultural Implements and for operating tipping trailer. The system has also got provision to attach additional Aux valves for rear and front mounted attachments. The rear mounted implements are coupled to the tractor using Three Point Linkage (3PL) System. The hitch hydraulics system consists of hydraulic pump, filter, piping’s, fittings and hydraulics lift unit. Hydraulics lift unit consists of a proportional control valve, cylinder, piston and power linkages. Conventional control valve is hydro mechanical part operated by mechanical linkages. The control valve and linkages plays major role in performance of hydraulics system. Hydraulics is required to operate in extreme conditions of soils such as very soft like sand to very hard like black cotton sand.
Technical Paper

Design of Light Weight Hydraulic Connecting Rod for Agricultural Tractor

2019-10-11
2019-28-0016
Hydraulic power train assembly of an agricultural tractor is meant to controls the position and draft of the implement depending upon the type of crop, farming stage, implement type and soil conditions. These variations induce extreme range of loads on the hydraulic system, thus making it challenging to design these components. Hydraulic connecting rod is critical component of hydraulic power train assembly. Standards like IS12224, IS4468 governs the design of hydraulic power train components which regulates the test method for hydraulic power and lift capacity of the tractor. In this paper, a virtual simulation process has been established to design a hydraulic connecting rod to meet the requirements. The hydraulic connecting rod basically functions as a short load transferring link, which is subjected to the operating hydraulic pressure of the hydraulic lifting mechanism. The current circular connecting rod is higher in weight and cost.
Technical Paper

Develop the Methodology Using DOE Approach to Improve Steering Return Ability of a Vehicle through Virtual Simulation

2019-10-11
2019-28-0012
In driving, Steering is the input motion to the vehicle. The driver uses steering input to change the direction of the vehicle. During Parking or U turn bends the Steering is locked and later released to follow the desired path. Steering return ability is defined as the ratio of difference between steering wheel position at lock condition and steering wheel angle after 3 seconds of release to the steering wheel angle at lock condition. Having proper steering return ability characteristics has an important effect on vehicle steering characteristics. In this study, a full vehicle ADAMS model is prepared, and virtual steering return ability have been simulated in ADAMS/CAR for a Pickup truck vehicle. Simulated responses in the steering wheel angle have been validated by comparison with measurements. A Design of Experiment study is setup and Iterations are carried out to find the effect of Hard points and friction parameters.
Technical Paper

Estimation of Clutch Life for Manual Transmission Vehicle Through Thermal Modeling of Clutch Housing and Clutch Facing

2017-10-08
2017-01-2439
Poor clutch life is a major issue for some light commercial vehicle models. Clutch overheating is the primary cause for clutch failure. Some of the reasons include inappropriate gear selection by the driver, poor low-end dynamic torque availability from an engine, heavy stop and go traffic, vehicle overloading resulting in excessive clutch slippage especially in gradients, riding of the clutch pedal by the customer etc. These situations lead to a high thermal energy dissipation at the clutch, increasing clutch wear and in extreme conditions leading to not only poor shift quality but also eventual clutch failure. Unfortunately, it is not practical to monitor clutch temperature in a production vehicle due to high costs or technical challenges involved. This paper describes 1-D thermal modeling of single plate dry clutch typically used in passenger car/truck and bus applications. The objective of simulation is to estimate the temperature rise on the clutch facing and clutch housing.
Technical Paper

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

2020-04-14
2020-01-1280
As the FTP-75 drive cycle does not have a prescribed gear shift pattern, automotive OEMs have the flexibility to design. Conventionally, gear shift pattern was formulated based on trial and error method, typically with 10 to 12 iterations on chassis dynamometer. It was a time consuming (i.e. ~ 3 to 4 months) and expensive process. This approach led to declaring poor fuel economy (FE). A simulation procedure was required to generate a gear shift pattern that gives optimal trade-off amongst conflicting objectives (FE, performance and emissions). As a result, a simulation tool was developed in MATLAB to generate an optimum gear shift pattern. Three different SUV/UV models were used as test vehicles in this study. Chassis dyno testing was conducted, 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

Improved Powertrain Mounts Position for Four Cylinder Engine Commercial Vehicle with Four Point Mounting Configuration

2016-02-01
2016-28-0231
In this era of engine downsizing, the powertrains with higher power densities are configured on next generation vehicles. The bare four cylinder engine without balancer shaft has higher surface velocities, sound pressure & power levels and nearly 10 to 15% higher base level vibration/forces over older generations. Adapting such engines on a new vehicle platform with stringent NVH targets is challenging. Powertrain mount modal analysis, 6DOF or 16DOF is a primary tool followed for initial mount positioning and stiffness definition. From our earlier experiences we have the knowledge that most of the 6DOF iterations lead to the mount positions which are less feasible as per vehicle architecture and packaging point of view, and further optimization is needed to arrive at suitable mount position through 6DOF analysis. In a drive to have first time right solution with minimal modifications, the study was conducted to understand the role of mount position & isolation on different vehicles.
Technical Paper

Instrumentation Technique Used for Design Optimization of Front Axle Support Bracket in Agricultural Tractor

2019-01-09
2019-26-0083
Agriculture tractor industry is highly competitive in the current market scenario with global majors competing in various markets. A tractor having an optimum design is of prime importance to keep the cost low while providing higher value to the customers. Technology advances in instrumentation methodology and data acquisition helps not only in providing the right inputs for the design of a component/system but also very much useful for design/system optimization. Front Axle Support of an agricultural tractor is one of the structural member which is connected to the Chassis which is called skid of the tractor to which the Front Axle is mounted through Pillow block (Plummer block) arrangement to facilitate axle oscillation about the tractor longitudinal center line. Front ballast weights are mounted on a bracket which is intern mounted to the front axle support to maintain the required front reaction in various agricultural operations.
Technical Paper

Investigation and Mitigation of Brake Squeal Noise in Medium Commercial Vehicle

2020-10-05
2020-01-1607
The braking systems for modern day commercial vehicles with GVWs ranging above 7.5 metric tons use the typical s-cam drum brake system, where pressurised air is the actuating medium. The s-cam drum brake systems are popular today even after the advent and penetration of air disc brake systems, the main reasons being, cost-effectiveness, robustness, satisfactory performance and good component life. However, the brake systems of commercial vehicles (both M and N category) are frequently grappled with NVH issues particularly in the form of brake squeal noise (low frequency and high frequency). The noise with frequency more than 500 Hz can be generally defined as brake squeal. There has been a lot of work done and is being continued, at theoretical level, analytical level and experimental level to tackle with this issue.
Technical Paper

Investigation and Resolution of Vehicle Brake Judder

2020-10-05
2020-01-1609
One of the major discomforts while driving any medium to heavy commercial vehicle is brake judder. Brake juddering can be defined as vibrations felt on steering wheel or brake pedal or cabin floor, when brakes are applied at certain speeds and pressures. The frequencies of this judder lie as high as 500 Hz to as low as 10Hz. The brake juddering can be caused by a number of factors because of which providing universal solution only from brakes point of view is difficult. Some of the causes are related to part fitment, part quality, material selection, manufacturing process, Design consideration, environmental factors, peripheral aggregates etc. This paper gives us a brief idea about resolution of juddering problem in intermediate commercial vehicle by DOE method, and this methodology can be applied in heavy commercial vehicles also.
Technical Paper

Methodology for Investigation and Resolution of Zero/Low/Unstable Lining Gap Concern in S-cam Brake System

2020-10-05
2020-01-1641
S-cam air brake system is provided in almost all commercial vehicles having tonnage above 7.5-ton. In S-Cam brake system, drum to liner gap (henceforth referred to as 'liner gap' or simply 'gap' for convenience) range is an important factor which can impact braking behavior during brake application. Different OEMs (Original Equipment Manufacturers) define different liner gap ranges between S-cam brake lining and brake drum. This range depends majorly on the internal mechanism deployed in ASA (Auto Slack Adjuster). When these liner gaps start lowering i.e. when they fall in the range of 0 to 0.4 mm, or they become unstable (checked by feeler gauge at inspection window provided on dust cover of S-cam) then it starts impacting brake behavior in the subject vehicles.
Technical Paper

NVH Analysis of Powertrain Start/Stop Transient Phenomenon by using Wavelet Analysis and Time Domain Transfer Path Analysis

2015-06-15
2015-01-2293
Tactile vibration during vehicle key on/off is one of the critical factors contributing to the customer perceived quality of the vehicle. Minimization of the powertrain transient vibration in operating conditions such as key on/off, tip in/out and engagement/disengagement of engine in hybrid vehicles must be addressed carefully in the vehicle refinement stage. Source of start/stop vibration depends on many factors like engine cranking, engine rpm at which the combustion process starts and rate of engine rpm rise etc. The transfer path consists of elastomeric mounts of powertrain and the part of vehicle structure from mounts to tactile response location. In this paper, the contribution of rigid body motion of powertrain of a front wheel drive vehicle during key on/off is analyzed in both frequency and time domain. The signal is analyzed in frequency domain by using fast fourier transform, short time fourier transform and wavelet analysis.
Technical Paper

Parametric Modelling & High-Fidelity Algorithms for Vehicle Weight Estimation for Optimized Concept Vehicle Architecture

2019-10-11
2019-28-0036
The concept definition phase of typical vehicle development focuses on the architecture definition and optimization based on different constraints/requirements. With the focus on Sustainability, the architecture optimization process must include “Light-weighting” as an optimization criterion. With only concept vehicle architecture available, the vehicle weight estimation becomes judgmental & inaccurate. This paper aims to address this deficiency with a new analytical approach for vehicle weight estimation. The new approach for vehicle weight estimation is a “bottom-up” approach using parametric models for each system weight with the inputs being the relevant vehicle specifications driving the system engineering. For size/shape-driven (rather than functional) systems, the models are content-based & segment-based. The parametric models are then iterated for multiple architecture concepts & specifications and the optimum concept (meeting all functional & business constraints) is chosen.
Technical Paper

Reduction of Driveline Boom Noise and Vibration of 40 Seat Bus through Structural Optimization

2017-07-10
2017-28-1926
In today’s automotive scenario, noise vibration and harshness (NVH) has become a synonym for quality perception. This paper evaluates the problem of vibration and noise experienced in M2 category 40 seat bus and suggests the counter measures. Severe vibration is experienced on the bus floor, predominantly towards rear part of the bus. Vibration along with acoustic boom occurs prominently in 4th gear wide open throttle operating condition between 1300-1600 rpm of the engine. This paper focuses on reducing NVH levels by working on the transfer path with little modifications on power-train. Preliminary torsional measurements conducted on powertrain indicated high torsional excitation in the driveline during the problematic rpm zone. Further, Operational Deflection Shape (ODS) analysis revealed that the transfer path to the cabin is rear differential unit and suspension links. The dominant frequencies were identified along the transfer path and suitable modifications were done.
Technical Paper

Silent Block Bush Design and Optimization for Pick-Up Truck Leaf Spring

2017-03-28
2017-01-0455
Structural elastomer components like bushes, engine mounts are required to meet stringent and contrasting requirements of being soft for better NVH and also be durable at different loading conditions and different road conditions. Silent block bushes are such components where the loading in radial direction of bushes are high to ensure the durability of bushes at high loads, but has to be soft on torsion to ensure good NVH. These requirements present with unique challenge to optimize the leaf spring bush design, stiffness and material characteristics of the rubber. Traditionally, bushes with varying degree of stiffness are selected, manufactured and tested on vehicle and the best one is chosen depending on the requirements. However, this approach is costly, time consuming and iterative. In this study, the stiffness targets required for the bush were analysed using static and dynamic load cases using virtual simulation (MSC.ADAMS).
Technical Paper

Split Type Crankcase Design for a Single Cylinder LCV Diesel Engine

2017-01-10
2017-26-0040
Serious efforts have been put in space to focus on lowering the fuel consumption and CO2 discharge to the environment from Automotive Diesel Engines. Though more focus is put on material up gradation approach on weight perspective, it is accompanied by undesirable cost increase and manufacturing complexity. As a part of development of a single cylinder engine for a light commercial vehicle application, a unique approach of integrated split type crankcase design is designed and developed. This design have addressed all the key factors on Weight, Cost and Manufacturing perspectives. The split type crankcase configuration, particularly middle-split configuration, integrates the oil sump, front cover and flywheel housing in a single unit beneficial from the point of view of reducing engine weight and thus reducing the manufacturing costs. This crankcase is also excellent from the serviceability point of view.
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