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The stringent emissions standards in the late 1990's like NLEV, ULEV and SULEV have led to major modifications in the composition and design of ceramic substrates. These changes have been necessitated to reduce cold start emissions, meet OBD-II requirements, and to ensure 100,000 mile durability requirement in a cost-effective manner. This paper presents the key advances in ceramic substrates which include lower thermal expansion, lighter weight, higher surface area and improved manufacturing process all of which help meet performance requirements. In addition to above benefits, the compressive and tensile strengths of lightweight substrates, as well as their thermal shock resistance, are found to be adequate following the application of high surface area alumina washcoat. The strength properties are crucial for ensuring safe handling of the substrate during coating and canning and for its long term mechanical durability in service.

A mechanical system simulation package such as the Dynamic Analysis Design System (DADS) has been built to handle a wide variety of mechanical models. Such a software package must be able to handle mechanisms from fields as diverse as automotive, aerospace and agriculture. To efficiently solve a wide variety of mechanisms more than one solution technique must often be employed. This paper discusses the different integration algorithms used in DADS.

Non-noble metal based catalysts offer a cost-effective substitute for commonly used noble metal automotive catalysts. Perovskite type catalyst compositions are again becoming attractive mainly due to their low-cost, higher thermal stability, resistance towards poisoning species and a great degree of flexibility in the composition and structure for their possible tailoring to meet the specific catalytic requirements. However, catalytic activity and light-off characteristics of these catalysts are often reported to be comparatively inferior, which has ultimately limited their applications, particularly in respect of stringent emission norms with cold-start test procedures. Some new perovskite based catalyst compositions have been studied using alumina washcoated metallic substrates. These catalysts show excellent thermal stability, and there light-off characteristics have been remarkably improved by properly using metallic substrates.

Extruded ceramic honeycombs are used as substrates for catalytic converter in automotive emission control. The low thermal expansion and thus high thermal shock resistance(TSR) of cordierite honeycomb monoliths are important since monoliths have to withstand severe thermal stresses during the use. Besides thermal expansion, flexural strength and modulus of elasticity are the factors effecting TSR. To meet the demanding requirement of high conversion efficiency with low pressure drop and long durability, the honeycombs of variety of cell density and wall thickness are designed. Various Cordierite honeycombs are extruded and thermal properties are studied and correlated with calculated values and presented in this paper. The thermal expansion is measured in two directions, using a Dilatometer. Anisotropy in thermal expansion is observed in all the samples. Thermal expansion is found to be low along the channels and high across the wall.

Catalytic performance can be improved by reducing heat capacity and increasing geometric surface area (GSA). The effects of the catalyst layout and the substrate cell structure were investigated on the catalytic performance. The catalyst layout covers an under-floor catalyst only, a close-coupled catalyst with an under-floor catalyst and a close-coupled catalyst only, and a dual-bed close-coupled catalyst only. The substrate cell structure covers from conventional 6 mil/ 400 cpsi substrate to the ultra thin-wall and high cell-density substrate of 2 mil/ 900 cpsi. Significant reduction of emissions can be achieved by moving the catalyst location upstream of the exhaust gas and combined with using the ultra thin-wall and high cell-density substrates. Furthermore, dual-bed design demonstrated further improvement of catalytic performance at close-coupled location.

It is generally accepted that the process of catalyst deactivation originates from the entrance sections of the converter and gradually progress towards the exit. The purpose of this paper is to investigate the possibility of a catalyst operating life extension via a mounting inversion, when the catalyst is close to its limits in the normal position. The experimental results indicate that under full load conditions at 3000 rpm improvement of catalyst efficiency can be accomplished reaching approximately 30% for CO and HC. This mounting inversion can be easily accomplished by an appropriate symmetric design of the monolith casing and mounting flanges, so that smooth gas flow conditions can be attained in both flow directions.

Environmental regulations are going to put severe demands on the oil industry for improving fuel quality. Awareness about increasing contribution of automotive vehicles to air pollution particularly in major Indian cities has led to the enforcement of more and more stringent vehicle emission regulations. Emission norms to be applicable from April 1, 2000 for gasoline and diesel vehicles call for major changes in the engine design and a substantial improvement in the present level of fuel quality. Various fuel characteristics significantly affect the vehicle emissions. Main properties of attention are content of lead, sulphur, benzene, aromatics, olefins and oxygenates, and fuel stability in case of gasoline; and cetane number, distillation range, oxidation stability, aromatics content, sulphur content and density in case of diesel fuel. This paper presents a review of the worldwide trends in fuel quality changes for meeting emission norms.

In the absence of Anthropometric and Ergonomic data on Indian Driving population, a project entitled “Ergonomic study on Indian driving population” was under taken by The Automotive Research Association of India, Pune with assistance of the Government of India and the Indian Automotive industries. The objective was to survey and compile anthrpometric data in standing, sitting and preferred driving position for 4-wheeler and 2-wheeler driving positions to assist the automobile manufacturers in India to cater their design to Indian population and make an Indian driver comfortable. This paper briefly presents the methodology adopted for the survey along with the results. Also studies were conducted on finger pressure, hand pressure and foot pressure exerted by the driver, which would serve as the baseline data for designing controls for the vehicle. A comparison with a typical American data has revealed many correlation and differences.

Wind tunnel experiments in an idealized van model is conducted to study the flow characteristics in different cross-wind and overtaking conditions. Static pressure distribution along the mid longitudinal and horizontal sections of the model are performed at yaw angles of 0° (no cross-wind), 10°, 20° and 30° in a 0.6m by 0.6m, low speed, suction type wind tunnel. The overtaking process is simulated by using two similar models simultaneously, one dummy model and other the measuring model in various in-line and off-center conditions. Cross wind results in higher pressure in the wind-ward side as compared to the lee-ward side, thereby causing a strong yawing moment. The stagnation region shifts towards the wind-ward side, with increase in yaw angle. During overtaking process, the proximity of another vehicle decreases the pressure distribution on top and at the overtaking side of the vehicle, possibly due to the venturi like effect.

The exhaust emissions of two and three wheelers contribute to a major extent to the pollution in urban areas of South East Asia and especially India. Most of this class of vehicles are equipped with 2 stroke engines, which operate constantly rich, - leading to high carbon monoxide and hydrocarbon emissions. On the other hand the NOx concentration in the exhaust gas is neglegible. In near future more stringent exhaust gas legislation get effective in a number of countries. Therefore catalytic aftertreatment devices are necessary to meet the emissions limits. Hot Tubes™ and/or monolith type catalysts can be applied. The high exhaust gas hydrocarbon concentrations lead to high exotherms on oxidation which drives the exhaust gas temperatures up to a range between 750 and 850°C. Therefore thermal ageing of the Hot Tubes™ and monolith type catalysts is severe. The design of advanced catalyst systems has to take this into account.

The authors developed a simple simulation method of motorcycle emission mode, using a popular chart calculation software for a personal computer, to calculate from the motorcycle's various specifications and the engine bench test data. The precision or verification by a mass production model was of a sufficiently good level. This simple simulation method was easy to use and effective in reducing the research period. Moreover, the experimental motorcycle (Scooter, Two-stroke, 50cm3) that adopted the stratified combustion system for a fuel economy improvement and CO2 reduction, was made and experimented on the ECE40 mode as a sample case. Approximately 20 % of fuel economy improvement and CO2 reduction were achieved and the estimation was effectively proved.

Six-seater three-wheelers have gained popularity among the commuters especially for their point to point low fares and better frequency compared to Municipal buses. However, pressure is mounting from all the quarters to ban these vehicles or to drive them out of the municipal limits. These vehicles with maximum loading capacity of 550 kg employ diesel engines which emit high soot & particulate matter or 2-stroke petrol engines which emit carbon monoxide as high as 13 g/km and hydrocarbon as high as 8 g/km, alarmingly high above the 1996 emission norms of 6.75 g/km CO and 5.40 g/km HC. Also the noise levels were higher. Considering the above threat, the authors had taken up the challenge to investigate and curb the pollution by employing high durability metallic catalytic converters.

Finite element method has been used for modal and vibration / stress analysis of a passenger vehicle. The study vehicle has been discretised taking into account the chassis elements, axles, suspension and tyres. The Lanczos method has been successfully used for the modal analysis. The power spectral density (p.s.d.) of acceleration of a track measured by using three height sensors has been fed as input to the tyres and the dynamic response of the vehicle in terms of acceleration and strain has been computed at all the nodes using finite element modeling and the random vibration concept. The experiments were carried out using piezo-electric accelerometers and strain gauges to measure the vibration and strain levels at critical points of the vehicle. The vibration and strain levels calculated through f.e.m. match well with the experimental values.

This paper describes the experience gained during the successful development of a catalytic converter design for an in-line 4 cylinder application to meet the India 1998 cold start emissions standards. The vehicle application considered was an open loop carburetted system that met the 1997 hot start emission standards using a conventional Pt/Rh underbody mounted catalyst. The challenge was to meet the 1998 standards through catalyst changes and/or minor carburettor adjustments, thus providing the customer with the most cost-effective solution. The approach adopted was to use a mathematical computer simulation (MAESTRO™) developed by Delphi, that utilized engine out data obtained from emission testing of the vehicle to simulate proposed solutions. The biggest advantage of this approach was the ability to estimate the impact of system level changes on emissions performance thus enabling a quick optimization of the design variables.

A cam actuated injection system timed to inject CNG fuel near the engine intake valve in the intake manifold at the end of suction stroke, but just before the closure of intake valve, has been designed, developed and incorporated in the S.I. engine. Details of the injection system hardware and injector drive mechanism developed are presented. A comparative experimental evaluation of the engine fuel economy and exhaust CO and NOx emission levels using premixed CNG-air induction system and Timed Manifold Injection(TMI) system developed is depicted. Engine test results show that with premixed CNG induction system the engine uses a relatively richer gas-air mixture as compared to that with TMI system. Power loss of the engine with premixed charge induction retrofit gets eliminated by using TMI system. Engine exhaust CO and NOx emission levels have been, in general, found to be lower with TMI system developed.

While evaluating the performance of a new vehicle, physical specifications and likely performance parameters of the vehicle are the only data known to the test driver. Effects of various ground irregularities encountered as shocks and vibrations that often catapult driver and vehicle into air can cause quantitative physiological changes associated with psychological implications on the subject driver. A test setup was developed at National Centre for Automotive Testing of VRDE, to study the response of test drivers on tracks containing irregularities. A medium crosscountry truck was used for the experimentation. The object of this paper is to study and exploit the results obtained from this test and examine whether they lead to some conclusion regarding effect of vibration spectra on physiological response of subject driver. The test results indicate that younger drivers with ideal height and weight combination showed lower level of stress symptoms.

Field endurance testing in New Delhi and surrounding area roads demonstrates the potential of catalytic devices for delivering long term reductions of HC + NOx and CO emissions from 2-wheel vehicles. Typically, catalytic performance is monitored periodically using chasis dynamometer mass emission test procedures. Unfortunately, mass emission testing is resource and time consuming. However, there is a relatively simple method for semi-continuously monitoring changes in catalyst performance during road aging. This relatively simple method of catalyst performance monitoring is discussed in this paper. In addition, the impact of extended vehicle operation during field testing and dynamometer endurance runs on catalyst performance is assessed for both 2 and 4 stroke motorcycles. Results examining catalyst deactivation mechanisms are examined for 2-wheel vehicles equipped with these 2 and 4 stroke engines.

Quality of Ride is one of the Important performance parameters of automotive vehicles, especially in the passanger vehicles. In this paper, the guidelines of ISO:2631-1997 and BS: 68441-1987 are applied on vehicles to assess the ride quality of vehicles objectively. Vibration inputs in terms of acceleration are acquired at 3 locations in 12 axes. These are then processed using the frequency weighting functions. The analysis gives a single number called “Overall Ride Value” which is proportional to passenger discomfort in vehicle. The axes which are principal sources of discomfort and the frequency range, which is most responsible for discomfort, are identified. The present work also includes experiments conducted to see the effect of variation in load, road surface, and vehicle speed on ride quality. The data obtained by this procedure can be used for assessment and comparison of ride quality characteristics of vehicles in detail.

This paper describes the functions and features of synchroniser system used in manual transmissions. It gives the details of the mathematical relationships involved in the synchroniser operation. A program is made in C to predict the gear shift effort required at the hand ball for a given manual transmission. The effect of various synchro parameters namely coefficient of friction, cone angle, blocker angle, synchronising time on gearshift quality and performance of manual transmission is studied. Benchmarking of a transmission, designed for usage with higher-powered engine, is carried out with proven transmissions in the same application.

Attemppts have been made to minimize structure-borne noise of body panels (drumming noise) of a 3-wheeled Pick-Up powered by a 4-Stroke Single Cylinder 175 cc gasoline engine. Vibration measurements at different points on the chassis over a wide range of vehicle speeds could identfy resonance frequencies of the structure. Frequency analysis of Sound Pressure Levels measured near Top Roof of the Pick-Up body showed dominance of the structural resonance. In order to reduce the vibrations at the source, crankshaft balance factor of the engine was optimized. The Body Panels were stiffened and also isolated by rubber pads from the chassis. The engine was respectively disconnected from the chassis at the front and the rear to know their individual contribution towards the drumming noise of the Body Panels.