Effectiveness of ECE R66 and FMVSS 220 standards in rollover crashworthiness assessment of paratransit buses

The main objective of the presented study was to compare the effectiveness of two standard test procedures for evaluating bus roof integrity: the dynamic rollover test according to UN-ECE Regulation 66 (ECE-R66), and the quasi-static symmetric roof loading according the Federal Motor Vehicle Safety Standard 220 (FMVSS 220). Both tests were applied to a selected Paratransit Bus. The investigation was carried out primarily using a numerical study backed up by experimental validation tests on components and full scale rollover tests. A sensitivity analysis using LS-OPT? was performed to identify the most important structural components influencing the response of the bus in these two tests. The results obtained from this study show that the final outcome of the crashworthiness assessment of the selected paratransit bus depends on the selection of the evaluation standard. Although the two tests are used for the same purpose of roof integrity evaluation, their results are divergent and may lead to different conclusions. The paper presents a discussion on the effectiveness of both standards in evaluating the rollover crashworthiness.     

Emissions simulation in a 7000 kg-grade diesel hybrid electric vehicle

Hybrids combine a combustion engine with an electric motor and battery. The two technologies can be combined to reduce fuel consumption and exhaust emissions. This paper presents the concept of hybrid electric vehicles (HEVs) applied to truck or van vehicles with diesel engines. The simulation results from the advanced vehicle simulator (ADVISOR) demonstrate that the required power may be properly shared between the internal combustion engine and electric motor. The simulation can also be used to prove that the technique is useful for improvements in driving performance; additionally, the technique is suitable for hybrid electric vehicles, allowing for good fuel economy and low emissions performance.     

Effect of the number of fuel injector holes on characteristics of combustion and emissions in a diesel engine

The diesel combustion process is highly dependent on fuel injection parameters, and understanding fuel spray development is essential for proper control of the process. One of the critical factors for controlling the rate of mixing of fuel and air is the number of injector holes in a diesel engine. This study was intended to explore the behavior of the formation of spray mixtures, combustion, and emissions as a function of the number of injector hole changes; from this work, we propose an optimal number of holes for superior emissions and engine performance in diesel engine applications. The results show that increasing the number of holes significantly influences evaporation, atomization, and combustion. However, when the number of holes exceeds a certain threshold, there is an adverse effect on combustion and emissions due to a lack of the air entrainment required for the achievement of a stoichiometric mixture.     

Noise,vibration, harshness model of a rotating tyre

ABSTRACT

The tyre plays a fundamental role in the generation of acoustically perceptible driving noise and vibrations inside the vehicle. An essential part of these vibrations is induced by the road excitation and transferred via the tyre into the vehicle. There are two basic ways to study noise, vibration, harshness (NVH) behaviour: Simulations in time and frequency domains. Modelling the tyre transfer behaviour in frequency domain requires special attention to the rotation of the tyre. This paper shows the approach taken by the authors to include the transfer behaviour in the frequency range up to 250?Hz from geometric road excitations to resulting spindle forces in frequency domain. This paper validates the derived NVH tyre model by comparison with appropriate transient simulations of the base transient model.     

Subjective absolute discomfort threshold due to idle vibration in passenger vehicles according to sitting posture

Idle vibration, occurring when a vehicle comes to a stop while the engine is on, is known to be a main cause of discomfort for passengers, and the customer effect has been recently growing. The frequency of idle vibration is determined by the engine type. To lower the vibration, various technologies have been applied to optimize the engine mount and vehicle body structure. In addition to the technological developments, research on human response with a consideration of idle vibration is needed to effectively reduce the level of discomfort experienced by passengers. Seats aimed at enhancing static comfort influence the sitting posture of passengers; sitting posture is a factor affecting human body characteristics that response to idle vibration. This study examined the absolute discomfort threshold of idle vibration according to the sitting postures of 13 taxi drivers. The four sitting postures of subjects on a rigid-body seat without a backrest were variables in the determination of absolute discomfort threshold of idle vibration. The absolute discomfort threshold curves obtained in this experiment were less sensitive to frequency changes than the frequency weighting function of ISO 2631-1.     

Coal-fixed turbines versus diesel: an Australian context

This paper considers the economics of the diesel engine as against that of coal-fired turbines for ship propulsion in the context of the world energy debate. After formulating a generalized model of propulsive plant choice the model is applied to a particular Australian export trade.