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The development of any sealing product invariably involves some form of physical leakage testing, and although this evaluates the performance of the product, it gives no insight to the fundamental sealing mechanism of the design. Elastohydrodynamic lubrication theory was used to study this problem. The study of hydrodynamic lubrication, where there is fluid flow, is, from a mathematical standpoint, the application of a reduced form of the Navier-Stokes equation with the continuity equation. This equation is well known as the Reynolds equation. However, normally, the Reynolds equation is derived from Cartesian co-ordinates where the curvatures of surfaces are ignored. However, a valve stem seal (VSS) works in an axisymmetric environment. This paper discusses the development of the elastohydrodynamic lubrication theory in a cylindrical co-ordinate system and its usefulness in the prediction of metered leakage across a valve stem seal.

Axisymmetric static Finite Element (FE) models were used to study sealing geometric changes on valve stem seals (VSSs). FE analysis is used to characterise the deformation of the rubber seal, and the contact pressure distribution. The deformations were analysed using animation techniques. The research gives a first order approximation, revealing magnitude and direction of seal lip to valve stem contact. Finally, a hypothesis on the sealing and lubricating mechanism is proposed.

A valve stem seal is designed to reduce oil flow from the valve train area of the cylinder head into the intake and exhaust port of the engine. However, these seals have to allow adequate lubrication of the valve stem / valve guide contact area and therefore need to provide a minimal amount of oil flow. Even such small quantities of oil passing the seals into the ports and the combustion chamber will effect engine emissions. Exhaust emission measurements on a modern 16 valve gasoline engine illustrate the seals contribution on total engine emissions and allow prediction of the effect of adjustments of the oil metering rate to actual engine requirements.

A new valve stem seal design has been developed to achieve superior control of the oil flow rate to valve guide. This design exhibits increased performance in the control of the oil flow rate under high pressures of the inlet or exhaust port and under high valve stem eccentricity. The recent demands of stable function, minimized oil consumption, and more efficient emission controls are achieved by this new design.

Brake squeal has been a chronic customer complaint, often appearing high on the list of items that reduce customers' satisfaction with their vehicles. Brake squeal can emanate from either a drum brake or a disc brake even though the geometry of the two systems is significantly different. A drum brake generates friction within a cylindrical drum interacting with two semi-circular linings. A disc brake consists of a flat disc and two flat pads. The observed squeal behavior in a vehicle differs somewhat between drum and disc brakes. A drum brake may have a loud noise coming from three or more squeal frequencies, whereas a disc brake typically has one or two major squeal frequencies making up the noise. A good understanding of the operational deflection shapes of the brake components during noise events will definitely aid in design to reduce squeal occurrences and improve product quality.

Due to its high specific power density, immediate and lively throttle response, good efficiency and life cycles comparable to current powertrain concepts the hydrogen internal combustion engine (H2-ICE) will play a major role in future automotive propulsion systems. The new bi-fuel 12-cylinder hydrogen internal combustion engine for the 7 series is an important step in this direction. In this article engine design and the development of the engine functions of the new H2-12-cylinder will be shown in detail. In particular the engine operation strategy to achieve high efficiencies and very low tail pipe emissions will be presented. Finally potentials of the mono-fuel derivative will be discussed and an outlook for future engine concepts will be given.

A technique to measure steering motion and loads for different steering gear systems is introduced. Data analysis and preparation for road test simulation are presented. Full vehicle simulation with different types of steering restraints on a 6DOF (six degrees of freedom) road test simulator is studied.

The purpose of this study is to clarify the influence of the maximum pressure on the lifetimes of compressed hydrogen tanks during ambient temperature pressure cycling tests. We varied the maximum pressure from 100% to 200% of designed filling pressure (FP) in five levels. Type 3 (Fully wrapped composite tank with metal liner): The tank's lifetimes, i.e. the numbers of cycles up to Leak Before Break (LBB), decreased with increasing maximum pressure. We observed that the internal surface of the liners had linear flaws resulting from the manufacturing process. Cracks causing LBB seemed to initiate from these flaws. Striation marks clearly appeared at the fracture surface of LBB cracks when the maximum pressure exceeded 125% of FP. Therefore, we suggest that LBB cracks were caused by a similar process of crack propagation in this range. In spite of the maximum pressure changes (100% to 200% of FP), tank strain was proportional to pressure at all times.

A peculiar type of flaking occasionally occurs on bearings that are used in automotive electrical instruments. This flaking, which is called brittle flaking, is accompanied by a unique microstructure change consisting of a white structure below the surface of the bearing raceway. Brittle flaking prevention is necessary because it occurs after such a short time in some applications. The cause of brittle flaking is considered to be hydrogen embrittlement. This paper presents the data from several tests in which direct current was passed through the bearings. The result was that the brittle flaking occurred on the bearing after a short time. Additionally, there was an increase in the amount of hydrogen retained in the bearing steel. By increasing the direct electrical current, the brittle flaking occurred in less time. Greases with various additives were tested in order to establish countermeasures for brittle flaking.

A study has been undertaken on a boosted single cylinder research engine with direct injection of hydrogen. In order to reduce NOx emissions and tendency to knock, efforts have been made to reduce the temperatures and rate of heat release during combustion. Lean boosted operation, stoichiometric operation with exhaust gas recirculation, and water injection using a dual fluid direct injector were investigated and NOx emissions, thermal efficiency, and combustion stability were compared. Conclusions are developed for specific power optimisation and NOx management which may be applied for hydrogen fuelling of small general purpose through to heavy duty engines.

This is a proposed alternative to the Ackermann Steering Mechanism. Synthesis of a six member mechanism taking seven precision points is performed for an automotive steering mechanism. The maximum rotation of inner wheel is taken as 65 degree to attain still less turning radius. The mechanism has been compared with those achieved by Ackerman Steering Mechanism (ASM), Fahey Eight Member Mechanism (FEMM) and Pramanik Six Member Mechanism (PSMM). The suggested mechanism gives fairly the accurate result that falls above the ASM mechanism. The mechanism gives better end response leading to shorter turning radius.

Hydrogen-fueled internal combustion engines (H₂ICEs) are an affordable, practical and efficient technology to introduce the use of hydrogen as an energy carrier. They are practical as they offer fuel flexibility, furthermore the specific properties of hydrogen (wide flammability limits, high flame speeds) enable a dedicated H₂ICE to reach high efficiencies, bettering hydrocarbon-fueled ICEs and approaching fuel cell efficiencies. The easiest way to introduce H₂ICE vehicles is through converting engines to bi-fuel operation by mounting a port fuel injection (PFI) system for hydrogen. However, for naturally aspirated engines this implies a large power penalty due to loss in volumetric efficiency and occurrence of abnormal combustion. The present paper reports measurements on a single-cylinder hydrogen PFI engine equipped with an exhaust gas recirculation (EGR) system and a supercharging set-up.

Diesel particulate filters (DPFs) equipped with diesel vehicles have become indispensable components to capture the soot emitted from the engines from a viewpoint of both human health and global warming problems as well as the prevailing regulations. Meanwhile, the pressure drop caused by them leads to a direct increase of fuel consumption. In order to reduce it guaranteeing the sufficient soot filtration efficiency, we have developed the new concept of asymmetric plugging layout for the DPF design, so-called Valuable Plugging Layout (VPL), on the basis of octosquare (OS) structure and have clarified the advantage of the pressure drop reduction both experimentally and theoretically. The VPL-DPF consists of two kinds of octagonal/square inlet channels and octagonal outlet channels, and there are thought to be five filtration velocity modes as well as four kinds of soot deposit layers on each side of the inlet channel walls.

The need to develop products faster and to have designs which are first time right have put enormous pressure on the product development timelines, thus making computer aided optimization one of the most important tool in achieving these targets. In this paper, a design of experiments (DOE) study is used, to gain an insight as to, how changes to different parameters of front suspension and steering of a passenger bus affect its kinematic properties and thus to obtain an optimized design in terms of handling parameters such as bump steer, percent ackermann error and lock to lock rotation angle of steering wheel. The conventional hit and trial method is time consuming and monotonous and still is an approximate method, whereas in design of experiments (DOE), a model is repeatedly run through simulations in a single setup, for various combinations of parameter settings.

The growing functionality and complexity of recent vehicle electronic systems have made inter-device communication (on-board LAN) technology vital to vehicle design. By field of application, the LAN (Local Area Network) systems currently in use are LIN (Local Interconnect Network) used for body systems, CAN (Controller Area Network) used for control systems, and MOST (Media Oriented Systems Transport ) used for multimedia and camera systems, and work to standardize the next-generation communication technology for each of those fields is underway. This paper provides a technical overview of the CXPI (Clock Extension Peripheral Interface) communication protocol, which satisfies the body system requirements (rapid response, system extensibility, high reliability, and low cost). It also presents the progress made on standardization at SAE and other organizations.

Due to benefits from the use of electric power, Hybrid Electric Vehicles (HEVs) and Plug-in Hybrid Electric Vehicles (PHEVs) are regarded to be superior over conventional Internal Combustion Engine (ICE) only vehicles in fuel economy and emissions. However, recent studies find out that this is not always true. On certain conditions, hybrid vehicles can be even more polluted. In order to identify these challenges and develop catalysts to meet more stringent emission requirement in the future, e.g. Euro 7, for hybrid application, as a part of our xHEV project, this study includes exclusively extensive investigation on a latest Euro 6d temp Parallel PHEV.

The aim of this paper was to describe a method of accelerated three way catalytic converter (TWC) ageing performed on the engine test bed for European On Board Diagnostics (EOBD) monitoring purposes and screening of different catalysts solutions. To accelerate the catalyst ageing process, the exhaust gas temperature was elevated to a range 1000 - 1200°C, which is typical for an ageing cycle performed using ovens. Catalyst emissions performance was checked at new condition (after degreening) and subsequently at predefined ageing intervals, based on the oxygen storage capacity (OSC) evaluation. The emission tests were performed in the laboratory on the chassis dynamometer using legislative cycles. The accelerated ageing method was found to be of use for verifying the EOBD functionality under vehicle operation with a degraded catalyst substrate.

The present work investigates the temperature distribution inside the diesel particulate filter (DPF) regeneration during the drop to idle test (DTIT), which is considered as life-threatening to the DPF. To study this scenario in detail, experiments were carried out with the filter volume of 3 liters. Initially, the experiments were done at a steady-state level, where the optimization for optimal soot loading was performed with setpoint temperature varying from 620 to 660°C. The soot loading was varied from 8 g/l to 11 g/l. The DTIT performed at a steady-state level indicated the different peak temperatures attained inside the DPF at different locations. The peak temperature was found to be in the center plane of the filter. The next peak temperature locations were found to be in downstream of the filter at different locations, which shows the non-uniformity in the soot deposition inside the filter.

The effective filtration area of a diesel particulate filter (DPF) can be improved by novel cell structure design and valuable plugging layout simultaneously without sacrificing the reduction of the inlet aperture ratio. A prototype silicon carbide DPF characterized with about more than 14 cm2/cm3 filtration area and more than 43% of the inlet aperture has been designed, optimized, and manufactured. Based on a single-cylinder diesel engine test bench, the performance of this prototype has been evaluated, such as its filtration efficiency, pressure loss, active/passive regeneration efficiency, etc.

Valve stem seals have been used for the various valve stem application of automotive engines by establishing the certain lubricating status between valve stems and valve guides. It is necessary that valve stem seals have stable controlled oil leakage characteristics relative to variables such as oil viscosity, shaft speed and shaft surface roughness. The practical aspect of the characteristics of the controlled oil leakage on valve stem seals for engine application in small size U.S. and Japanese passenger cars have been discussed in this paper.