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The ever-tightening regulation norms across the world emphasize the magnitude of the air pollution problem. The decision to leapfrog from BS4 to BS6 – with further reduction in emission limits -showed India’s commitment to clean up its atmosphere. The overall cycle emissions were reduced significantly to meet BS6 targets [1]. However, the introduction of RDE norms in BS6.2 [1] demanded further reduction in emissions under real time operating conditions – start-stop, hard acceleration, idling, cold start – which was possible only through strategies that demanded a cost effective yet robust solutions. The first few seconds of the engine operation after start contribute significantly to the cycle gaseous emissions. This is because the thermal inertia of the catalytic converter restricts the rate at which temperature of the catalyst increases and achieves the desired “light-off” temperature.

Bharat Stage VI emission norms were implemented in India in two stages: Stage I from April 1, 2020, and Stage II from April 1, 2023. For M & N category vehicles, the RDE test along with other applicable certification tests is mandatory for obtaining a BSVI compliance certificate during stages I and II. The RDE test is conducted on roads under real driving conditions, unlike the Type-I test, which uses a predefined cycle on the chassis dynamometer, during which the ambient temperature and other environmental conditions are controlled in a narrow range. During BSVI Stage I for the RDE test, there was no limit for any pollutant. Therefore, it is considered as the RDE monitoring stage, and from BS-VI Stage II, limits are enforced on a few pollutants (NOX and PN) as notified in notification GSR 226(E) dated March 27, 2023. Therefore, it is considered the RDE compliance stage.

A 2-D computational model was developed to describe the flow and filtration processes, in a honeycomb structured ceramic diesel particulate trap. This model describes the steady state trap loading, as well as the transient behavior of the flow and filtration processes. The theoretical model includes the effect of a copper fuel additive on trap loading and transient operation. The convective terms were based on a 2-D analytical flow field solution derived from the conservation of mass and momentum equations. The filtration theory incorporated in the time dependent numerical code included the diffusion, inertia, and direct interception mechanisms. Based on a measured upstream particle size distribution, using the filtration theory, the downstream particle size distribution was calculated. The theoretical filtration efficiency, based on particle size distribution, agreed very well (within 1%) with experimental data for a number of different cases.

The Fly-By-Light Advanced Systems Hardware (FLASH) program is developing Fly-By-Light (FBL) and Power-By-Wire (PBW) technologies for military and commercial aircraft. The flight control system portion of FLASH focuses on the integration of fiber optic sensors, optic data buses, actuators (PBW, smart, rotary thin wing) and optic cable plant components for centralized and distributed flight control architectures. Laboratory demonstrations will show applicability to widebody commercial transport and military tactical aircraft. This paper summarizes the requirements, objectives, key technologies and demonstration configurations of each of three FLASH flight control system developments.

For the past approximately 20 years, the Serial Peripheral Interface (SPI) has been the established standard for serial communication between a host or central microprocessor and peripheral devices. This standard has been used extensively in control modules covering the entire spectrum of automotive applications, as well as non-automotive applications. As the complexity of engine control modules grows, with the number of vehicle actuators being controlled and monitored increasing, the number of loads the central microprocessor has to manage is growing accordingly. These loads are typically controlled using discrete and pulse-width modulated (PWM) outputs from the microcontroller when real-time operation is essential or via SPI when real-time response is not critical. The increase of already high pin-count on microcontrollers, the associated routing effort and demand for connected power stages is a concern of cost and reliability for future ECU designs.

This paper provides measurement and analysis on rotor in-plane mode induced squeal. Methodology is presented to simultaneously acquire both temporal and spatial squeal operational deflection shapes (ODS). Rotor accelerations both in the in-plane and out-of-plane directions were measured during squeal along with rotor's normal ODS using a laser vibrometer. Modal measurement and analysis of the rotor and pad in the in-plane and out-of-plane directions were conducted as installed in system condition. The test results indicating rotor modal coupling in the in-plane are provided, and out-of-plane directions, and conclusions on in-plane mode induced squeal are proposed. In addition, the countermeasure for squeal reduction is discussed.

This paper discusses the analysis and measurement of the dynamic centre of pressure of a brake pad during a normal braking event. The technique is unique in its design and implementation. The process is progressive whereby the interface static measurements are first taken and then dynamic testing is carried out under braking. Two different measurement systems are considered during the analysis with one used to measure the center of pressure. Both the in-board and out-board pads are measured for wear but the piston pad was selected for pressure measurements. Validation of the spragging process is undertaken on both test rigs and vehicle trials. Pad wear measurements complement the collective information. The results show the position of the centre of pressure to vary considerably during a braking event, both radially and axially along the pad.

”Tire blow-out” is a fast loss of air pressure that fills a vehicle tire, effecting from a puncture or a fatigue of tire structure. Statistical data, published in the United States, showed that “tire blow-out” caused more than 300,000 road accidents in the period of 1992–96 [1, 3]. Over 2000 people died in those accidents and many more were injured [1, 3]. The data and successful attempts of simulation presented in the work [1], prompted the author to try modeling and simulating this case of vehicle motion. The main emphasis in the hereto presented tests was put on qualitative assessment of vehicle behavior after a “tire blow-out”. The results presented in the work [1] show that the smallest motion disturbance of a vehicle takes place when the driver does not react (by turning the steering wheel or pressing the brake pedal). So, an assumption was made that the driver keeps a zero value of the steering wheel turning angle and pressure on the brake pedal.

This paper will present an overview of research relating to tire-related accident studies and case studies in evaluating specific accident situations where tire disablements were also encountered. This paper also presents a comprehensive examination of selected accidents following tire disablements. Tire disablements include blowouts, tread separations, punctures, airouts, etc. Methodology for studying vehicle performance during tread separation is presented as well as results of full-scale tests where tread separations were induced. In this manner, vehicle transient response during tire disablements is also discussed. This paper also addresses warning signs preceding tire disablements that often accompany tread separation, as well as the human response in these situations.

In the brake system, unevenly distributed disc-pad contact pressure not only leads to a falling-off in braking feeling due to uneven wear of brake pads, but also a main cause of system instability which leads to squeal noise. For this reason there have been several attempts to measure contact pressure distribution. However, only static pressure distribution has been measured in order to estimate the actual pressure distribution. In this study a new test method is designed to quantitatively measure dynamic contact pressure distribution between disc and pad in vehicle testing. The characteristics of dynamic contact pressure distribution are analyzed for various driving conditions and pad shape. Based on those results, CAE model was updated and found to be better in detecting propensity of brake squeal.

Understanding the complex and dynamic nature of wheel-loader's operation requires a detailed system model. This paper describes the development of a conventional wheel-loader's system model that can be used to evaluate the transient response. The model includes engine details such as a mean value engine model, which takes into account turbocharger dynamics and engine governor controller. This allows the model to predict realistic performance and fuel consumption over a drive cycle. The wheel-loader machine is modeled in LMS Amesim® and the engine governor controller is modeled in Matlab/SIMULINK®. In order to simplify the model, hydraulic loads from the boom / bucket mechanism, steering and cooling fan are modeled as hydraulic load inputs obtained from typical short V-drive cycle. Critical wheel-loader drive cycle inputs into the model have been obtained from testing and have been used to validate the system response and cycle fuel consumption.

Composites are well-known to provide good weight reduction and more creative design freedom in automotive closure applications versus traditional ferrous or non-ferrous stamped metal assemblies. Challenges to widespread adoption of composite structures include: Recyclability of the end unit without disassembly Joining together panels Keeping up with high production volumes Limited structural strength without significant metal reinforcement Total delivered cost Latest generation composite liftgates can achieve high levels of component integration and maximum styling freedom by utilizing fully thermoplastic recyclable injected molded panels. Proper material characterization and CAE optimization can reduce the level of internal metal reinforcements, thereby realizing further weight reduction opportunity.

Tire tread separation events, a category of tire disablements, can be sub-categorized into two main types of separations. These include full tread separations, in which the tread around the entire circumference of the tire separates from the tire carcass, and partial tread separations, in which a portion of the tread separates and the flap remains attached to the tire for an extended period of time. In either case, the tire can remain inflated or lose air. Relatively, there have been few partial tire tread separation tests presented in the literature compared to full tread separation tests. In this study, the results of 25 full and partial tire tread separation tests, conducted with a variety of vehicles at highway speeds, are reported. Cases in which the tire remains inflated and loses air pressure are both considered. The testing was performed on a straight section of road and primarily focused on rear tire disablements.

Brake squeal is a phenomenon of self-induced vibration of the brake components during braking. There are many kinds of brake squeal cases whose mechanisms require acting on a various number of potential root causes. Brake squeal phenomena can be generally separated into 2 main mode types related to the direction of disc vibration involved: in-plane mode and out-of-plane mode. For out-of-plane mode, a number of existing countermeasures can be potentially applied after characterization of the squeal occurrence condition by direct experiment or simulation analysis[1,2,3,4]. However, as there are many possible mechanisms and root causes for the in-plane modes[5,6,7,8,9,10,11,12,13], it is generally necessary to perform a detailed analysis of the vibration mechanism before implementing a countermeasure.

This paper examines the onset of brake noise and the mechanisms involved during the initial stages of noise occurrence. The emphasis is directed towards disc mode coupling and improvements are suggested to inhibit the coupling of the in-plane and out-of-plane modes with similar frequencies. To better understand the mechanisms, modal analysis of the system is carried out in a static condition but with varying pressure loads. In addition the operational deflection shape (ODS) was recorded under normal braking conditions using tri axial accelerometers attached on a disc. It was identified by a 3D scanning technique during squeal braking. Through a parametric study and using complex eigenvalue analysis the disc mode shapes were reproduced and correlated to the system results. The proposals to reduce mode coupling were successfully evaluated on a brake dynamometer and the results were confirmed with vehicle testing.

This paper documents the vehicle response of a tractor-semitrailer following a sudden air loss (Blowout) in a steer axle tire while traveling at highway speeds. The study seeks to compare full-scale test data to predicted response from detailed heavy truck computer vehicle dynamics simulation models. Full-scale testing of a tractor-semitrailer experiencing a sudden failure of a steer axle tire was conducted. Vehicle handling parameters were recorded by on-board computers leading up to and immediately following the sudden air loss. Inertial parameters (roll, yaw, pitch, and accelerations) were measured and recorded for the tractor and semitrailer, along with lateral and longitudinal speeds. Steering wheel angle was also recorded. These data are presented and also compared to the results of computer simulation models. The first simulation model, SImulation MOdel Non-linear (SIMON), is a vehicle dynamic simulation model within the Human Vehicle Environment (HVE) software environment.

Successful trace chemical contamination control is one of the components necessary for achieving good cabin atmospheric quality. While employing seemingly simple process technologies, sizing the active contamination control equipment must employ a reliable design basis for the trace chemical load in the cabin atmosphere. A simplified design basis that draws on experience gained from the International Space Station program is presented. The trace chemical contamination control design load refines generation source magnitudes and includes key chemical functional groups representing both engineering and toxicology challenges.

In this study, tests were performed with modified tires at the various front and rear positions on seventeen different vehicles to determine the effect of a full tire tread belt separation on a vehicle at highway speeds. The driver's steering and braking inputs were measured along with the vehicle responses during the event. The results show that the forces of a full tread belt separation generally do not force a vehicle out of a driver's control and that only small steering corrections are required to remain in the original lane of travel during the tread belt separation event. Additionally, forces due to the separating tires do not result in violent hop or tramp suspension responses during the separation event.