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This paper presents an approach to product design verification in which efficient and effective design verification is a key deliverable of a function failure avoidance approach to engineering. The traditional approach to design verification is discussed. The relative advantages of conducting design verification at different levels within the system hierarchy are identified and the manner in which component level testing can be made representative of usage in the field is illustrated within an automotive case study. The use of small samples sizes, a reduced number of tests and a reduction of testing complexity as a part of effective design verification is explained. The role of computer based models as the basis of virtual testing within design verification is discussed.

This paper presents an investigation into the functional robustness of an in-tank fuel delivery system (FDS) used in a saddle type fuel tank application for a high performance petrol engine. Robust design tools were used to identify the noise factors that affect the performance of the in-tank FDS. A transfer function relating the system's response to key control and noise factors was developed using a combination of theoretical modeling based on fluid mechanics and component level experimentation. The transfer function was validated with data from system level testing. A sensitivity study using the transfer function was conducted to validate the performance of the system against key noise factors.

The complexity of powertrain calibration has increased significantly with the development and introduction of new technologies to improve fuel economy and performance while meeting increasingly stringent emissions legislation with given time and cost constraints. This paper presents research to improve the model-based engine calibration optimization using an integrated sequential Design of Experiments (DoE) strategy for engine mapping experiments. This DoE strategy is based on a coherent framework for a model building - model validation sequence underpinned by Optimal Latin Hypercube (OLH) space filling DoEs. The paper describes the algorithm development and implementation for generating the OLH space filling DoEs based on a Permutation Genetic Algorithm (PermGA), subsequently modified to support optimal infill strategies for the model building - model validation sequence and to deal with constrained non-orthogonal variables space.

This paper presents a methodology that makes use of computer based analytical simulation methods combined with statistical tools to predict timing belt life. This allows timing belt life to be estimated with no requirement for running test engines and associated test equipment, which is both very time and expense exhaustive. A case study on a belt driven primary drive for a V6 Diesel engine was used to illustrate the methodology. A computer based dynamic model for the belt drive system was developed and validated, and a belt life prediction model was developed, which uses tooth load predictions from the analytical model. Statistical modeling of predicted damage accumulated to failure was used to estimate the model parameters given a limited set of belt life results from a motored rig test. The practical use of the model is illustrated by predicting belt life under customer usage.

This paper introduces a function failure approach to Fault Tree Analysis (FFTA) and illustrates its application through an automotive case study. The methodology is structured and straightforward to use. It is argued that the FFTA methodology integrates and interconnects well with other failure mode avoidance tools in common use in the automotive engineering design, such as FMEA and P-Diagram. FFTA shares the same platform for function based system analysis as other analysis tools and delivers complementary information

This paper presents an approach to product design and development based on function failure avoidance, using of series of well known engineering tools including Function Fault Tree Analysis, P-Diagram and Design Verification. A 4-step function failure mode avoidance process is presented. The use of the engineering tools in an integrated and synergistic manner to achieve robust and reliable product design is illustrated by considering information flow within an automotive case study. The central role of FMEA within the process is described. The authors’ experience of using the process is discussed.

The strict regulation of environmental laws, the oil price and restricted resources has made the vehicle manufacturers to use other energy resources instead of fuel oil. Iran is recognized as the second holder of gas reservoirs in the world and can use hydrocarbon gases broadly in particular compressed natural gas (CNG) as the fuel for vehicles specifically in its public transportation fleet and thereby reduce the consumption of diesel fuel and gasoline. This will bring about the reduction of environmental pollutants and reduce the economic costs of transportation sector. With regard to the climatic situation of Iran and concerning the existence of broad network of gas distribution, CNG is a suitable alternative for other fuels. Therefore, developing bi-fuel engine (gasoline and CNG) in the short and middle term strategy for achieving this important subject will be necessary.

Braking system characteristics, brake system performance and brake system component design parameters that influence brake pedal ‘feel’ in a passenger car have been studied using the simulation modelling package AMESim, in particular to model the linear and nonlinear characteristics of internal components. A passenger car hydraulic brake system simulation model incorporating the brake pedal, booster, master cylinder, brake lines and calipers has been developed to predict brake system response to assist in the design of braking systems with the desired brake pedal force / travel characteristic characteristics to create good brake pedal ‘feel’. This has highlighted the importance of system components, in particular the master cylinder and caliper seal deformation, and the operating characteristics of the booster in determining the brake pedal force / travel characteristic.

Low frequency longitudinal vibrations resulting from driver throttle inputs are a common problem in modern passenger cars. This phenomenon, which is commonly referred to as shuffle or shunt, is due to sudden changes in the engine torque exciting torsional oscillations in the driveline. This paper presents a dynamic model of a vehicle driveline for the optimization of low frequency torsional vibration. The model used is first validated against experimental tests. Parameter sensitivity studies have been carried out using the model to identify the important components affecting shuffle. Three key parameters have been chosen from the parameter study. To optimize these key factors, Genetic Algorithms (GAs) have been used in this multi-parameter optimization problem. The results obtained from GAs have been compared with the calculus based optimization techniques.

The teaching of engine mapping and calibration provides a unique challenge to Universities and Technical institutes the world over. The engine test cell facilities required for such tuition is prohibitively expensive for many organizations, for those fortunate enough to have the facilities their use is often already oversubscribed. In any case it is not desirable to have untrained operatives experimenting with expensive and potentially dangerous equipment without very close time intensive supervision. In the School of Engineering Design and Technology at the University of Bradford, although fortunate enough to have a number of state-of-the-art transient engine test cells, these safety concerns are contrasted against students' frustrations at a lack of practical experience in this area for the above reasons.

The quality of the output generated by a team is directly influenced by how well the team works together. Despite the complexity of the team system, within a typical Design for Six Sigma (DFSS) project the consideration given to the team process is often disproportionately small in comparison to that paid to the technical aspects of the project. This paper presents an efficient approach to teamwork within an engineering design context such as a DFSS project, in which team skills are modelled on DFSS technical processes allowing team members to learn both technical and teamwork skills within the common context of the technical process. DFSS engineering tools used within the framework of Failure Mode Avoidance are used to identify key potential failure modes in the team process and their effects and causes. A series of effective and efficient countermeasures to the team process failure modes are introduced as straight forward and easy to use interlinking teamwork tools.

Vehicle drift is a condition where the driver must apply a constant correction torque to the steering wheel in order to maintain a straight-line course of the vehicle during braking. This paper presents an investigation study into the characteristics of a vehicle experiencing steering drift under straight line braking. The aim of the work is to study vehicle stability and the causes of vehicle drift/pull during straight line braking to minimize brake drift level and hence optimize safety measures. Simulation, modeling and analysis have been performed in a multibody dynamics environment based on actual vehicle data. The simulation study of steering drift during braking and the resulting unstable behavior of a vehicle during straight-line braking which results in lateral drift is presented in this paper. Suspension parameters have been modeled as rigid links joined with flexible bushes so as to observe their effect on a vehicle while braking.

This paper presents the development and implementation of an Analytical Target Cascading (ATC) Multi-disciplinary Design Optimisation (MDO) framework for the steady state engine calibration optimisation problem. The case is made that the ATC offers a convenient framework for the engine calibration optimisation problem based on steady state engine test data collected at specified engine speed / load points, which is naturally structured on 2 hierarchical levels: the ‘Global’ level, associated with performance over a drive cycle, and ‘Local’ level, relating to engine operation at each speed / load point. The case study of a diesel engine was considered to study the application of the ATC framework to a calibration optimisation problem. The paper describes the analysis and mathematical formulation of the diesel engine calibration optimisation as an ATC framework, and its Matlab implementation with gradient based and evolutionary optimisation algorithms.

This paper presents a design for reliability methodology based on the DfSS DCOV process, applied to the development of a cost effective timing chain drive for a four cylinder diesel engine. A CAE model for the timing chain drive was used to study the distribution of the chain loads, which provided an essential input both for the concept selection stage and for the development of a reliability model for the timing chain. A DoE study on the CAE model aimed at investigating the significant factors for chain load variability lead to a reliability improvement achieved by reducing the variability in the chain load through revising the tolerances for the sprocket tooth profile. The paper demonstrates the efficiency of the process and the usefulness of computer simulation in achieving reliability and robustness enhancement while reducing design and development time and costs.