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This study mainly focuses on oil consumption behavior of laser textured cylinder bores. The results of an experimental study performed on a six cylinder, 9.0 L capacity diesel engine is presented. The engine has Compacted Graphite Iron (CGI) cylinder block, and parent bore power cylinder design. Both an instantaneous oil consumption measurement method, sulfur-tracing, and a conventional oil consumption measurement method, “drain and weigh”, are used in determining the effects of different laser texture parameters at different running conditions. Oil consumption measurement results with the conventional plateau honed surface in comparison with the laser honed surface are also discussed.

This paper is on the design of a steer-by-wire system for a light commercial vehicle. A hardware-in-the-loop simulation test rig with the actual rack and pinion mechanism of the light commercial vehicle under study was built for this purpose. The steer-by-wire actuator can be placed on either the second pinion, the first pinion or both in the double pinion steering test system used. The hardware and geometry of the steering test rig are identical to the implementation of the steering system in the test vehicle. Unnecessary and expensive road testing is avoided with this approach as most problems are identified and solved in the hardware-in-the-loop simulation phase conducted in the laboratory where the steering subsystem and its controller exist as hardware and the rest of the vehicle exist as a software model running in real time. Hardware-in-the-loop simulation results show the effectiveness of the proposed controller design in tracking desired steering dynamics.

This paper presents the development of a transient active control (TABC) system for the Ford Transit Connect light commercial vehicle using semi active suspensions. The control objective is to improve the ride comfort and road holding together with achieving roll and pitch stability using four semi active suspension dampers, hence called transient active body control. Semi-active control algorithms such as sky-hook, ground-hook and hybrid are applied to each suspension while the roll and pitch stabilizing controllers are designed separately and interfere with the local semi-active controllers through a supervisory control algorithm, if necessary. Simulation and experimental results are presented to demonstrate the effectiveness of the proposed technique.

Tailsitter UAVs with their combined vertical take off and landing (VTOL) and fixed-wing aircraft with full flight-speed regime capability provides a distinct alternative to rotary-wing and ducted fan UAVs (OAVs). ITU-BYU Tailsitter concept aims to obtain the energy efficient regimes across the VTOL and the cruising flight regimes. This paper describes the hybrid propulsion system design approach to attain this. The preliminary design and the analysis indicate advantageous performance over other mini-class unmanned air vehicles.

There is an increasing trend in the worldwide automotive area towards developing hybrid electric vehicles as an intermediate solution to fulfill the new, more stringent pollutant emission level requirements set by governments. Conversion of braking energy into electrical energy stored in the battery through regenerative braking is an important aspect of hybrid electric vehicles that increases their fuel efficiency. This paper presents an electric regenerative power assisted brake algorithm developed to enhance energy efficiency of a front and rear wheel drive parallel hybrid electric commercial vehicle. The commercial vehicle used in this study is a second generation research prototype Ford Transit Parallel Hybrid Electric Van. The existing hydraulic brake system of this van was not altered for reasons of safety and reliability in the case of a problem with regenerative barking.

In a Hybrid Electric Vehicle (HEV), the main aim is to decrease the fuel consumption and emissions without significant loss of driving performance. Maximizing Overall Efficiency Strategy (MOES) algorithm, presented here, distributes the power demand among the available paths to the wheels to improve fuel economy. In MOES, the vehicle is considered as a system whose input and output are power capability of consumed fuel and actual power transferred to the road, respectively. The aim of the strategy is to maximize the overall efficiency of the vehicle determined as the ratio of output power to input power. The control algorithm and driver model were prepared within Simulink and used to drive the Carmaker model of the vehicle which is a Ford Transit hybrid electric research prototype van. Simulations were carried out in 3 modes of the vehicle; conventional mode, regenerative braking only mode and full MOES mode to analyze the role of optimization better.

Efficient use of oil resources has become the number one priority throughout the world. Vehicles, operating with alternative fuels like solar or hydrogen energy are still in the development phase. In this transition period, automotive companies are trying to produce more efficient road vehicles to reduce the negative impacts of the internal combustion engine. Advances in high-efficiency electrical machines (EM), high-specific energy/power units, lower-cost power electronics and embedded systems have promoted the use of EM solely and/or along with the internal combustion engine (ICE) to develop pollution-free vehicles. Due to the high cost of the energy storage units for a pure electric drive the current trend is towards the practice of hybrid electric vehicle (HEVs).

Road inputs are one of the most significant components of operational loading of motor vehicles and their exhaust systems. Even if road profiles remain the same, the response spectrums measured on exhaust system components vary for different vehicle and exhaust system combinations. Existing exhaust system product development and design approval procedures require multi-channel data acquisition on vehicles under specified driving conditions and at proving grounds to cover all representative customer usage events. After analysis and reduction, damage relevant sections of this data package will be used for test lab simulation purposes. This vehicle instrumentation and data acquisition process is very time consuming and cost intensive. The method presented here is based on the calculation of the dynamic characteristics of each road segment, or road events using road measured acceleration time histories, and lab measured transfer functions of vehicle body and suspension.

Engine design is crucial in terms of NVH. It is the sources of vibration for a vehicle. Nowadays engine tends to being smaller and less stiff and more powerful according to predecessor. Small engines with high power is inherently generates extreme force and vibrations and accordingly generates more noise. Thus engine structure and also engine main components should be designed to prevent this vibration. There are two main sources: One of them is combustion and other is inertia loads. Due to this sources engine structure can cause severe vibration and accordingly this can cause noise via transmitting it into vehicle with both structure and airborne. This paper focused on to reduce engine vibration level with changing the combustion inputs such as cylinder pressure parameters and inertia parameters like piston mass, conrod length and balancing parameters. Design of experiment is used to obtain most robust case in terms of NVH.

The brake torque variation (BTV) generated due to geometric irregularities in the disc surface is generally accepted as the fundamental source of brake judder; geometric imperfections or waviness in a disc brake caliper system is often quantified as the disc thickness variation (DTV). Prior research has mainly focused on the vibration path(s) and receiver(s), though such approaches grossly simplify the source (frictional contact) dynamics and often ignore caliper dynamics. Reduction of the effective interfacial contact stiffness could theoretically reduce the friction-induced torque given a specific DTV, although this method would severely increase static compliance and fluid volume displacement. An experiment is designed to quantify the effect of disc-pad contact modifications within a floating caliper design on BTV as well as on static compliance.

In recent years, due to the growing problem of environmental pollution and climate change internal combustion engine stroke volume size has been reduced. The use of down-sized engines provides benefit for reducing emissions and fuel consumption especially at the inner city driving conditions. However, when the engine demands additional power, utilizing a turbocharging system is required. This study is a joint work of Istituto Motori CNR with Automotive Laboratory of Mechanical Engineering Faculty of Istanbul Technical University (ITU) and the objective of this study was devoted to increase the understanding of various engine operating conditions on emissions, especially at low load. The trade-off between Nitrogen Oxide (NOx) and Particulate Matter (PM) emissions in a Diesel engine has been examined depending on turbocharging rates and the rate of Exhaust Gas Recirculation (EGR) applied.

It is an important problem to estimate the fatigue life of spot welds. There are a number of spot weld models in literature put forward to represent spot welds in finite element models. In this study, five popular spot weld models are compared with each other and experimental results. It is concluded that 9-point contact method is the best one among other models considered in this study based on strain measurements. In terms of fatigue tests, 9-point contact and umbrella models yield better-correlated results than the rigid and elastic beam models.

In this paper, the optimum linear/nonlinear spring and linear/nonlinear damper force versus displacement and force versus velocity characteristic functions, respectively, are determined using simple lumped parameter models of a quarter car front independent suspension and a half car rear solid axle suspension of a light commercial vehicle. The complexity of a nonlinear function optimization problem is reduced by determining the shape a priori based on typical shapes supplied by the car manufacturer and then scaling it up or down in the optimization process. The vehicle ride and handling responses are investigated considering models of increased complexity. The linear and nonlinear optimized spring characteristics are first obtained using lower complexity lumped parameter models. The commercial vehicle dynamics software Carmaker is then used in the optimization as the higher complexity, more realistic model.

A method for automatic reduction of detailed reaction mechanisms using simultaneous sensitivity, reaction flow and lifetime analysis has been developed and applied to a two-zone model of an SI engine fuelled with Primary Reference Fuel (PRF). Species which are less relevant for the occurrence of autoignition in the end gas are declared redundant. They are identified and eliminated for different pre-set minimum levels of reaction flow and sensitivity. The resulting skeletal mechanism is valid in the ranges of initial and boundary values for which the analyses have been performed. A measure of species lifetime is calculated from the chemical source terms, and the species with the lifetime shorter than and mass-fraction less than specified limits are selected for removal.

For manual transmissions, including the automated types, reduced shifting effort and easy of gear set engagements in a short period of time without rattles and shakes are major requirements for the shift quality evaluations. Performance of the synchronizer mechanisms depends highly on the design, material and arrangement of the transmission synchronization components; thus, the synchronization process is a mechanical and tribological process which is influenced by numerous design parameters of the synchronizers, constraints and properties of the lubricated contacts. In this study, a detailed multi-body-dynamics model for a HCV (Heavy Commercial Vehicle) transmission gearset is presented; various synchronization simulations are performed and the results are compared with the objective shift quality measurements. The developed model yields total synchronization and engagement time based on the applied gear shifting effort.

In an effort to support design and testing activities at product development lifecycle of the engine, proper duty cycle is required. However, to collect data and develop accurate duty cycles, there are not any vehicles equipped with prototype engines at customers. Therefore, in this paper, discrete duty cycle development methodology is studied to generate trailer truck engine usage profile which represents driving conditions in Turkey for engines in development phase. Cycles are generated using several vehicles equipped with prototype engines and professional drivers that can mimic customer usage. Methodology is based on defining real-world customer driving profile, discretizing real-world drives into separate events, collecting vehicle data from each discrete drive, determining the weight of events by conducting customer surveys and creating a representative reference usage profile with data analysis.

With the advent of the KIVA-4 code which employs an unstructured mesh to represent the engine geometry, the gap in flexibility between commercial and research modeling software becomes more narrow. In this study, we tried to perform a full cycle simulation of a 4-stroke HD diesel engine represented by a highly boosted research IF (Isotta Fraschini) engine using the KIVA-4 code. The engine mesh including the combustion chamber, intake and exhaust valves and helical manifolds was constructed using optional O-Grids catching a complex geometry of the engine parts with the help of the ANSYS ICEM CFD software. The KIVA-4 mesh input was obtained by a homemade mesh converter which can read STAR-CD and CFX outputs. The simulations were performed on a full 360 deg mesh consisting of 300,000 unstructured hexahedral cells at BDC. The physical properties of the liquid fuel were taken corresponding to those of real diesel #2 oil.

A timing drive model was developed based on computer-aided simulation methods and used to calculate the contribution of each system component to the overall timing drive friction loss at various engine operating conditions. Combining the analytical results and statistical methods, an optimization study was performed to calculate the ideal system design parameters such as hydraulic tensioner spring force and flow rate, sprocket tooth profiles and circularity, and oil supply pressure. The simulation results revealed that while the plastic guide - timing chain friction is responsible for the most part of the frictional losses, the contribution of timing chain friction increases with increasing speed. It was found that the tensioner guide is the key element in the guiding system that causes friction losses. Furthermore, tensioner spring force and engine oil pressure were identified as major design parameters that influence the efficiency of the timing drive.