Moumen Idres

Vehicle Fuel Consumption and Emission Modelling: An In-Depth Literature Review

Modelling of vehicle fuel consumption and emissions has emerged as an effective tool to help develop and assess vehicle technologies and to help predict vehicle fuel consumption and emissions. A review to identify the current state-of-the-art on vehicle fuel consumption and emissions modelling is elucidated. This review categorises vehicle fuel consumption and emissions models into five classifications. The relevant main models to each of these classifications are presented. These models are then compared with regard to assumptions, limitations, merits, drawbacks, characteristic parameters, data collection techniques, accuracy, and relevance to road traffic. The study demonstrates that the trends of vehicle fuel consumption and emissions provided by current models generally do satisfactorily replicate field data trends. In addition, the paper demonstrates that mesoscopic models, empirical models, mean value-based models, and quasi dimensional models strike a balance between accuracy and simplicity and thus are very suitable for transportation and control applications. The study shows as well that no one model as yet fully meets the needs of transportation applications.

Optimisation of vehicle front-end geometry for adult and pediatric pedestrian protection

This study proposes a method of achieving an optimised vehicle front-end profile for improved protection for both adult and child pedestrian groups, which at the same time is able to avoid designs that may cause Run-over scenarios. A hybrid model of a seven-parameter vehicle front-end geometry and a pedestrian dummy is used. Latin Hypercube sampling is utilised to generate a Plan of Experiments for the adult and child pedestrian cases. Head injury criteria results from the simulations that are tabulated as the response functions. The radial basis function method is used to obtain mathematical models for the response functions. Optimised front-end geometries are obtained using the Genetic Algorithm method. The optimised vehicle front-end profile for the adult pedestrian is shown to be different from that of the optimised profile for the child pedestrian, and optimised profiles are shown to be not mutually applicable for safety. Furthermore, Run-over scenario is observed in child pedestrian optimised profiles, where its occurrence invalidates the optimisation. A simple weighting method is used to optimise the geometry for both adult and child pedestrian groups. The Run-over occurrences are mapped using Logistic Regression and is subsequently used as a constraint for optimisation. The final optimised model is shown to achieve a safe vehicle front-end profile which equally caters for both adult and child pedestrians while simultaneously avoiding Run-over scenarios.

Parametric study for head injury criteria response of three-year olds in a child restraint system in oblique and lateral intrusive side impact

A parametric study is undertaken to ascertain the sensitivity of the child restraint system (CRS) design, with respect to oblique side impact at standard velocities in consideration of intrusion. A hybrid model is constructed using a combination of both finite elements and multi-body ellipsoids where a three-year-old Hybrid III child dummy is placed inside a CRS and restrained with a harness system. A prescribed structural motion simulation of a side-impact crash is carried out based on experimental data. Validation is performed and the model is shown to be acceptable for common standard injury responses as well as being greatly economical in terms of computational processing time. A plan of experiments is prepared based on the Latin hypercube sampling for six parameters involving two different crash velocities. The head injury criterion (HIC) is considered as the response in this study. The model is adapted for intrusion and oblique impact. Response surface models are shown to be suitable for the mathematical modelling of the problem and Students t-test is used to assess the parameter sensitivity both qualitatively and quantitatively. Most of the parameters are seen to have greater significance for wider principle direction of force (PDOF) angles above 60°. In general, a gradual decrease in significance is observed for parameters with increasing impact velocity, with the notable exception of the impact angle. The impact angle is shown to most notably affect the HIC especially from PDOF angles 45°–75°, identified as the critical impact angle range. The far side shoulder harness slack parameter is also found to be significant in reducing the HIC.

Lateral Side Impact Crash Simulation of Restrained 3 Year Old Child

Motor vehicle crashes have become the leading cause of death for children in many developed countries and the trend is on the rise in Malaysia. Child anatomy and physiology necessitates a separate restraints system to be implemented during vehicle travel. Although approximately twice as many crashes with a child fatality are frontal compared to lateral, it is shown that side impacts are nearly twice as likely to result in a child fatality as frontal impacts. Due to the complexity and the highly non-linear nature of vehicle crash affecting occupants, much work still remains to be looked into. This is especially so in the study of injury mechanisms towards efforts of improving CRS design as well as vehicle parameters that may offer more effective and robust injury mitigation. The study here presents a methodology which outlines the development and testing of a simulation model where a 3 year old child, restrained in a CRS within a vehicle, is subjected to lateral side impact by a bullet vehicle. A combined environment of both Finite Element as well as Multi-body is used for the model development. A HYBRID III dummy model is used to represent the child while an FE model is used for the CRS model. A hybrid modelling method is utilized for the belt harness system. The model and simulation conditions are set based on the global FMVSS standard. Head injury criterion and Neck injury criterion are primarily considered in the model assessment. Model development as well as validation steps are presented with discussion of the model’s salient features for greater insights in the study of injury mechanisms.

Air supply system transient model for proton exchange membrane fuel cell

Proton exchange membrane (PEM) fuel cells are considered one of the best potential alternative power sources. It has both high efficiency and high power density. The air supply system dictates the performance of the fuel cell. It is responsible for supplying the correct amount of mass flow rate which is essential for ensuring efficient reaction of hydrogen and controlling the pressure inside the cathode. Pressure has a direct effect on the water balance characteristics and efficiency. In this work, a dynamic model for the air delivery system, including compressor and supply manifold, is developed. The model can capture both flow and inertia dynamics of the compressor. The model is tested by simulating the transient performance of the air supply system for a transportation-size fuel cell. A feedforward control method based on the compressor map is developed. Results show the success of the model in predicting the transient behaviour of the air supply system. The model can be used to implement and test different control strategies.

Injury analysis validation of a deformable vehicle front end model

In the event of an impact with an automobile, pedestrians suffer multiple impacts with the bumper, hood and the windscreen. The characteristics of a vehicles front end and structural stiffness have a significant influence on the kinematics and injury risk of the pedestrians body regions, in a vehicle-to-pedestrian collision. In this present study, the injury risk of the pedestrian is investigated in an impact with a deformable vehicle front end model for the purpose of validating the developed model. A simplified vehicle front end model consisting of a multi body windscreen and a finite element cowl, hood and bumper is developed. The MADYMO human pedestrian multi body dummy model is impacted by the vehicle front end model at the speed of 40 km/h. The injuryto the various body segments namely the head, neck, sternum, lumbar, femur and tibia is obtained. The simulation values are compared to the experimental values for verification of the vehicle front end model.

Improving the efficiency of micronozzle by heated sidewalls

Heat developing by electrical field within a uniform side wall of micronozzle is established and its effect on nozzle flow parameters is tested. The continuum two-dimensional flow analysis of gas and onedimensional thermal analysis of the uniform sidewall are solved numerically and simultaneously for different configurations of heat supplying. Heat developing in the convergent-divergent sidewall shows improvement of thrust level and specific impulse due to an increase in both density and pressure at the exit section, although there is a degradation of Mach number and velocity and increase in the thickness of the subsonic boundary layer. Heat generation rate can be increased under limitations of the base metal structural properties. It is observed that heat exchange at convergent and divergent sections is more effective than preheating at the straight section before the entrance of the nozzle. It is found that; choosing the inlet boundary condition at the starting point of convergence shows additional pres...

Design optimization of a hybrid electric vehicle powertrain

This paper presents an optimization work on hybrid electric vehicle (HEV) powertrain using Genetic Algorithm (GA) method. It focused on optimization of the parameters of powertrain components including supercapacitors to obtain maximum fuel economy. Vehicle modelling is based on Quasi-Static-Simulation (QSS) backward-facing approach. A combined city (FTP-75)-highway (HWFET) drive cycle is utilized for the design process. Seeking global optimum solution, GA was executed with different initial settings to obtain sets of optimal parameters. Starting from a benchmark HEV, optimization results in a smaller engine (2 l instead of 3 l) and a larger battery (15.66 kWh instead of 2.01 kWh). This leads to a reduction of 38.3% in fuel consumption and 30.5% in equivalent fuel consumption. Optimized parameters are also compared with actual values for HEV in the market.

Investigation of Malaysian Low Earth Orbits for Remote Sensing Applications

This paper explores the orbit design procedures of a low Earth satellite orbit for remote sensing mission. The mission objective is to gather images over Malaysia as an area of interest for a variety of applications such as land monitoring and digital mapping. The design procedures are mainly driven by the payload performance, lighting conditions and the coverage requirements. Standard CubeSat platform with a NanoCam is considered for the mission. Numerical investigations show the trade studies of various satellite orbital parameters and their impact on the performance. The orbital parameters are optimized to meet the mission design requirements.

Trajectory tracking in quadrotor platform by using PD controller and LQR control approach

The purpose of the paper is to discuss a comparative evaluation of performance of two different controllers i.e. Proportional-Derivative Controller (PD) and Linear Quadratic Regulation (LQR) in Quadrotor dynamic system that is under-actuated with high nonlinearity. As only four states can be controlled at the same time in the Quadrotor, the trajectories are designed on the basis of the four states whereas three dimensional position and rotation along an axis, known as yaw movement are considered. In this work, both the PD controller and LQR control approach are used for Quadrotor nonlinear model to track the trajectories. LQR control approach for nonlinear model is designed on the basis of a linear model of the Quadrotor because the performance of linear model and nonlinear model around certain nominal point is almost similar. Simulink and MATLAB software is used to design the controllers and to evaluate the performance of both the controllers.