Search Results

Diesel Exhaust Fluid (DEF) concentration monitoring is done to detect the concentration at which the emission thresholds are exceeded in BSVI engines [1]. This paper introduces a novel method to model the fault monitoring system with enable conditions designed to detect deterioration in DEF concentration, while reducing misdetection. This eliminates the need for dedicated sensor, reduces complexity, cost, and potential sensor-related failure modes. Traditionally, Diesel Exhaust Fluid quality sensors have been employed to measure the absolute concentration of Diesel Exhaust Fluid in the aqueous solution of urea [2]. This information is used to detect usage of poor quality DEF which results in increase in NOx emission beyond legal limits.

In the commercial vehicle business, vehicle availability is a pivotal factor for the profitability of the customer. Nonetheless, the intricate nature of the technologies embedded in modern day engines and exhaust after-treatment systems coupled with the variability of the duty cycles of end applications of the vehicles imposes added challenges on the vehicle's sustained performance and reliability. In this context, the ability to predict potential failures through tools like telematics and real-time data analytics presents a significant opportunity for original equipment manufacturers (OEMs) to deliver distinctive value to their customers.

The Heavy Duty live rear axles in commercial vehicle helps to transmit the drive to the rear wheels and also carries vehicle load. The rear axle along with wheel assembly consists of axle casing, differential unit, half shafts, wheel hub, brake drum, brake chamber and wheels. It is one of the major safety critical element in any commercial vehicle. Based on the suspension type, rear axle housing also carries V rod & radius rod mountings & Spring Seat /Wear pad / Rubber Bolster (in case of bogie suspension). This paper abbreviates the contribution of bogie suspension seating configurations & V-rod Forces on life of heavy duty bogie rear axle casing. In-service DRT hot spot observations were reported on heavy duty rear axle on few models with bogie suspension. In order to find the root cause, devising a proper testing and analysis method is of prime importance. An extensive effort was made to device test methodology based on customer application and field visits.

The gearbox is a crucial aggregate in a diesel truck. Gearboxes must work efficiently to get the job done properly and lubrication is vital to this efficiency. Lubricating oil is like the circulation system of a gearbox. If the oil levels fall too low, the gearbox will likely fail. Gearbox failure can lead to expensive repairs that could be prevented. Besides added costs due to replacement or repair, costs associated with a loss of production could be significant. These issues are why; it is important to understand the consequences of having low lubricant levels. Similarly, higher oil level creates higher churning losses, heating of the Gear oil and oxidation, reduction in efficiency and increased oil leaks. Understanding the functions of gearbox lubricating oil can help you choose the right quantity of prevent gearbox failures.

Due to the emerging technologies and globalization, expectations of the customers on commercial vehicles are getting increased over the period. It is an important duty of an OEM to deliver a perfectly configured product to suit the customer requirements. When it comes to configuration of a vehicle, engine power is one of the key factors which indicate the performance of that vehicle. There is a tough competition between every OEM to increase the engine power for enhancing the overall operational performance. One method to increase power is to improve its volumetric efficiency. This is achieved with help of turbocharger and Charge Air Cooler (CAC). CAC improves volumetric efficiency by increasing intake air-charge density. Any failure on CAC leads to lower the volumetric efficiency and increase in turbocharger loading. This paper deals with the validation of CAC assembly using different test conditions by analyzing potential failure modes against the field issues.

In automobiles, front axle assembly is a main load bearing member and houses steering linkages. Front axle assembly has two main parts namely axle beam and axle arm, interconnected by a kingpin. This kingpin allows the rotation of axle arm during steering events. To avoid metal to metal contact between axle arm and kingpin, bushes are housed on the top and bottom half of the axle arm & in axle beam. Due to radial load and steering rotation, as a weak member, bushes will wear out faster. This affects the proper functioning of steering mechanism. Hence, the bushes need to be evaluated prior to its implementation in vehicle. In general, bushes are evaluated using Pin-On-Disc test as a comparative study, but it does not simulate exact boundary conditions as in vehicle. Next option is vehicle level validation but leads to more testing time and cost. Hence, as an optimized solution, the same vehicle operating conditions can be replicated in component level testing.

One of the important factors strongly required by customers nowadays is lower noise and vibration in vehicle. In this paper the prime focus is made on the study of effect of driveline angles on the noise and vibration behavior in a 4X4 configuration commercial vehicle. The impact of propeller shaft angles in the transfer of driveline excitations to the transmission and the resulting noise and vibration is studied. An abnormal noise was perceived from transmission and the root cause was investigated for the same. These excitations were high due to the higher driveline angles as this was design requirement to maintain higher ground clearance. A two-stage approach was adopted to modify the effect (transmission) and cause (propeller shaft angle) there by reducing the abnormal noise and vibration perceived in the vehicle.

Automotive business is more focused towards delivering a highly durable and reliable product at an optimum cost. Anything falls short of customer expectation will ruin the manufacturer’s reputation. To exterminate this, all automotive components shall undergo stringent testing protocol during the design validation process. Nevertheless, there are certain factors in the field which cannot be captured during design validation. This paper aims at developing a validation methodology for engine oil sump by simulating field failure. In few of our vehicles, field failure was observed in engine oil sump near the drain plug location. Preliminary analysis was carried out to find the potential causes for failure. Based on the engine test bed results, multi frequency swept sine testing was carried out in laboratory. Field failure was simulated in the lab test and the root causes for failure were found out.

With a push for urbanization across cities, there is an increased demand for mobility in public transportation especially buses which are provided through state transport undertakings. Hence, the expectations of this class of vehicles will be high in terms of quality and comfort to the passengers. The noise inside the passenger area of the bus becomes an important parameter, which sets apart a bus manufacturer from its competitors. The driveline of the bus is the system responsible for the transfer of power from engine to the wheels. The noise and vibration problems associated with it are detected only in the late stages of the design chain, when all its elements are tested together over a wide range of conditions. Since, calibration of engine and the selection of transmission is freezed in early stages, satisfying power and torque requirements, the only viable option left to address the problem is by optimizing the clutch parameters.

In the emerging commercial vehicle sector, it is very essential to give a product to customer, which is very reliable and less prone to the failures to make the product successful in the market. In order to make it possible, the product is to be validated to replicate the exact field conditions, where it is going to be operated. Lab testing plays a vital role in reproducing the field conditions in order to reduce the lead time in overall product life cycle development process. This paper deals with the design and fabrication of the steering column slip endurance test rig. This rig is capable of generating wear on the steering column splines coating which predominantly leads to failure of steering column. The data acquired from Proving Ground (PG) was analyzed and block cycles were generated with help of data analyzing tools.

All automotive components, systems and vehicles undergo stringent validation protocol standards. Nevertheless, there are certain factors which cannot be captured during validation phase and result in field failures. With multiple players prying for market share in the automotive industry, timely resolution of field failures can go a long way in retaining customer base. In such a scenario, when customer’s tolerance on field failures is very limited, failures need severe attention and must be captured as early as possible to cut down warranty expenses. This project aims at creating a methodology to simulate field failures and validate improved design. The reliability parameters such as β (Shape Factor), η (Scale factor), Reliability and life are estimated and the values are compared between field and lab conditions. Life estimated in field conditions (Failure data base) and lab are correlated using Reliability techniques and target is established for validating improved sample.

Engine noise reduction is one of the highest priorities in vehicle development from the viewpoint of meeting stringent noise regulations. Engine noise reduction involves identification of noise sources and suppression of noise by changing the response of sources to input excitations. Noise can originate from several mechanical sources in engine. The present work focuses on systematic study of the behavior or response of engine structure and its ancillaries to engine excitation and thereby assess their contribution to overall engine noise. The approach includes engine noise and vibration measurement and component ranking using engine noise and vibration measurement in a non-anechoic environment, structural analysis of engine including experimental modal testing of engine and its components, etc. Correlation of the above obtained results is performed to identify the noise sources. Later, ranking of critical components was performed based on results of cladding exercise.

Powertrain is the major source of noise and vibration in commercial vehicles and has significant contribution on both interior and exterior noise levels. It is vital to reduce the radiated noise from powertrain to meet customer expectations of vehicle comfort and to abide by the legislative noise requirements. Sound intensity mapping technique can identify the critical components of noise radiation from the powertrain. Sound intensity mapping has revealed that oil sump as one of the major contributors for radiated noise from powertrain. Accounting the effect of dynamic coupling of oil on the sump is crucial in predicting its noise radiation performance. Through numerical methods, some amount of work done in predicting the dynamic characteristics of structures filled with fluid. This paper discusses on the capability of numerical approach in predicting the oil sump modal characteristics with fluid-structure interaction and consequent verification with experimental modal test results.

Lifting axles are auxiliary axles that provide increased load carrying capacity in heavy commercial vehicles. Lift axle gives better fuel efficiency as well as it reduces the operational costs by means of increasing the loading carrying capacity. These axles are raised when the vehicle is in unloaded condition, thus increasing the traction on remaining wheels and reducing the tire wear which in turn lower down the maintenance cost of the vehicle. Lifting height and force requires to lift the whole mechanism and are two main considerable factors to design the lifting axle mechanism. Although in India currently, the use of lift mechanism of single tire with continuous axle is more common. But in the case of pusher axle, continuous axle is unable to lift more after certain height because of the draft angle of the propeller shaft, and single tire axle which has less load carrying capacity up to 6T (Tons).

In the modern automotive sector, durability and reliability are the most common terms. Customers are expecting a highly reliable product but at low cost. Any product that fails within its useful life leads to customer dissatisfaction and affects the reputation of the OEM. To eradicate this, all automotive components undergo stringent validation protocol, either in proving ground or in lab. This paper details on developing an accelerated lab test methodology for steering gearbox bracket using fatigue damage and reliability correlation by simulating field failure. Initially, potential failure causes for steering gearbox bracket were analyzed. Road load data was then acquired at proving ground and customer site to evaluate the cumulative fatigue damage on the steering gearbox bracket. To simulate the field failure, lab test facility was developed, reproducing similar boundary conditions as in vehicle.

As technology gets upgraded every day, automotive manufacturers are paying more attention towards delivering a highly reliable product which performs its intended function throughout its useful life (without any failure). To develop a reliable product, accelerated combined stress testing should be conducted in addition to the conventional design validation protocol for the product. It brings out most of the potential failure modes of the product, so that necessary actions can be taken for the reliability improvement. This paper discusses about the field failure simulation and reliability estimation of automotive headlamp relays using accelerated combined stress testing. To analyze various field failure modes, performance and tear down analysis were carried out on the field failure samples. Field data (i.e. electrical, thermal and vibration signals) were acquired to evaluate normal use conditions.

This abstract work describes a method of data acquisition and validation procedure followed for a metal bumper used in commercial vehicle application. Covariance is considered as major phenomenon for repeatable measurements in proving ground data acquisition and it is to be maintained less than 0.05. In this project covariance of data acquisition is analyzed before physical simulation of acquired data. In addition to that, multiple testing conditions like uni-axial and bi-axial testing were carried out to attain the failure. PG data is used for bi-axial vibration test and conventional constant spectrum signal (CSD signal) is used for uni-axial vibration test. Target duration for uni-axial test (Z direction) was arrived using pseudo damage calculation. Strain gauges were installed in failure locations to compare PG data and rig data as well as to calculate strain life. Failures were simulated in bi-axial vibration test.

Torsional vibration is a characteristic phenomenon of automotive powertrains. It can have an adverse impact on powertrain related noise as well as the durability of transmission and drivetrain components. Hence minimizing torsional vibration levels associated with powertrains has become important. In this context, accurate measurement and representation of angular acceleration is of paramount importance. A methodology was developed for in-house vehicle level torsional vibration measurement, analysis and representation of results. The evaluation of torsional vibration has two major aspects. First, the acquisition of raw rotational data and secondly, the processing of acquired data to arrive at usable information from which inferences and interpretations can be made about the behavior of the rotating element. This paper describes the development process followed for establishing a torsional vibration evaluation methodology.

Automotive component light weighing is one of the major goals for original equipment manufacturers (OEM's) globally. Significant advances are being made in developing light-weight high performance components. In order to achieve weight savings in vehicles, the OEM's and component suppliers are increasingly using ultra-high-strength steel, aluminum, magnesium, plastics and composites. One way is to develop a light weight high performance component through multi material concept. In this present study, a bimetal brake drum of inner ring cast iron and outer shell of aluminum has been made in two different design configurations. In two different designs, 40 and 26% weight saving has been achieved as compared to conventional gray cast iron brake drum. The component level performance has been evaluated by dynamometer test. The heat dissipation and wear behavior has been analyzed. In both designs, the wear performance of the bimetal brake drum was similar to the gray cast iron material.

Commercial vehicle NVH attributes primarily focus on interior noise for driver's comfort and exterior noise for environmental legislation. Major sources for both the interior and exterior noise are power train unit, exhaust and air intake system. This paper focuses on development of Air Intake System (AIS) for better interior and exterior NVH performance for medium and heavy commercial vehicles. For air intake system, structural radiations from its panels and nozzle noise are significant contributors on overall vehicle NVH. Noise generation mechanism in air intake system occurs due to opening and closing of the valves and inlet air column oscillation by sharp pressure pulse from cylinder. Based on benchmarking, vehicle level targets have been arrived, and then cascaded to system and sub-system level targets. For air intake system, targets for nozzle noise at wide open throttle condition have been set for exterior NVH performance.