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Title: Artificial neural network as a predictive tool for emissions from heavy-duty diesel vehicles in Southern California

Author(s): N Hashemi, N N Clark

Source: International Journal of Engine Research

Volume: 8 No 4 Pages: 321-336. Aug 2007

DOI: 10.1243/14680874JER00807

Publisher: Professional Engineering Publishing

Abstract:
An artificial neural network (ANN) was trained on chassis dynamometer data and used to predict the oxides of nitrogen (NOx), carbon dioxide (CO2), hydrocarbons (HC), and carbon monoxide (CO) emitted from heavy-duty diesel vehicles. Axle speed, torque, their derivatives in different time steps, and two novel variables that defined speed variability over 150 seconds were defined as the inputs for the ANN. The novel variables were used to assist in predicting off-cycle emissions. Each species was considered individually as an output of the ANN. The ANN was trained on the Highway cycle and applied to the City/Suburban Heavy Vehicle Route (CSHVR) and Urban Dynamometer Driving Schedule (UDDS) with four different sets of inputs to predict the emissions for these vehicles. The research showed acceptable prediction results for the ANN, even for the one trained with only eight inputs of speed, torque, their first and second derivatives at one second, and two variables related to the speed pattern over the last 150 seconds. However, off-cycle operation (leading to high NOx emissions) was still difficult to model. The results showed an average accuracy of 0.97 for CO2, 0.89 for NOx, 0.70 for CO, and 0.48 for HC over the course of the CSHVR, Highway, and UDDS.

Title: Suppression of heavy-truck driver-seat vibration using sliding-mode control and quantitative feedback theory

Author(s): N I Rajapakse, G S Happawana, Y Hurmuzlu

Source: Proceedings of the I MECH E Part I Journal of Systems and Control Engineering

Volume: 221 No 5: Page: 769 - 779. July 2007

DOI: 10.1243/09596518JSCE216

Publisher: Professional Engineering Publishing

Abstract: The current paper presents a robust control method that combines sliding-mode control (SMC) and quantitative feedback theory (QFT) for designing a driver seat of a heavy vehicle to reduce driver fatigue. A mathematical model is considered to analyse tracking control characteristics through computer simulation in order to demonstrate the effectiveness of the proposed control methodology. The SMC is used to track the trajectory of the desired motion behaviour of the seat. However, when the system enters into sliding regime, chattering occurs owing to switching delays as well as vehicle system vibrations. The chattering is eliminated with the introduction QFT inside the boundary layer to ensure smooth tracking. Furthermore, using SMC alone requires higher actuator forces for tracking than using both the control schemes together, and causes various problems in selecting hardware. Problems with noise amplification, resonances, presence of uncertainties, and unmodelled high-frequency dynamics can largely be avoided with the use of QFT over other optimization methods. The main contribution of the present paper is to provide guidance in designing the controller to reduce heavy vehicle seat vibration so that the driver's sensation of comfort maintains a certain level at all times.

Title: A study of commercial vehicle brake judder transmission using multi-body dynamic analysis


Author(s): K Hussain, S H Yang, A Day

Source: Proceedings of the I MECH E Part K Journal of Multi-Body Dynamics

Volume: 221, Number 2 / 2007 Pages 311-318

DOI: 10.1243/1464419JMBD23

Publisher: Professional Engineering Publishing

Abstract:
Braking-induced forced vibration, known as brake judder in road vehicles, causes dissatisfaction to drivers and passengers and also damage and possible early failure in components and systems. In this paper, the transmission of judder vibration from the point of generation (the brake friction pair) through the vehicle structure to the driver is investigated for the particular case of a heavy commercial vehicle. The investigation uses a computer simulation multi-body dynamic model based on the automatic dynamic analysis of mechanical systems software to identify any characteristics of the vehicle suspension design that might influence the vibration transmission from the wheel to the driver.

The model uses a simplified rigid chassis and cab to lump the chassis parameters, so that the investigation can focus on the front axle/suspension design, which is a beam axle leaf spring arrangement, and the rear axle/suspension assembly, which is a tandem axle bogie design. Results from the modelling indicate that brake judder vibration is transmitted to the chassis of the vehicle through a leaf spring ‘wind-up’ mode and a ‘walking’ mode associated with the rear tandem axle. Of particular interest is the longitudinal vibration transmitted through the chassis, since this creates a direct vibration transmission path to the cab and driver. The simulation results were compared with the previously published experimental work on the same design of commercial vehicle, and agreement between the predicted and the measured vibration characteristics and frequencies was found.

It is concluded that the rear suspension design parameters could affect the transmission of brake judder vibration to the cab and driver and that a tandem rear axle offers some design opportunity to control the transmission of brake judder vibrations from the wheel to the cab and driver. Given that brake judder has so far defied all attempts to eliminate completely from vehicle brake systems, this is potentially an important opportunity.

Title: Analysis of lateral sloshing forces within road containers with high fill levels

Author(s): J A Romero, O Ramírez, J M Fortanell, M Martinez, A Lozano

Source: Proceedings of the I MECH E Part D Journal of Automobile Engineering

Volume: 220 Page: 303-312. March 2006

DOI: 10.1243/09544070JAUTO42

Publisher: Professional Engineering Publishing

Abstract: This paper describes the experimental assessment of lateral sloshing forces developed within scaled road tankers as a function of fill level and container shape, focusing on high fill levels (from 90 to 98 per cent) and three container shapes (oval, modified oval, and circular). The purpose of the study was to estimate the effect of sloshing forces on the lateral stability of tank trucks when operating almost fully loaded. Water was used as the working fluid while the lateral dimensional characteristics of the containers represented a reduction scale of road tankers in the range of 1:5. Containers were subjected to a lateral excitation imparted by a sinusoidal electromagnetic shaker that moved a wheeled container/support assembly at a range of frequencies. The residual after-perturbation sloshing forces were measured by means of a force transducer connected to the shaker ram, and recorded for analysis. For the 98 per cent fill level, normalized sloshing forces were found to represent up to 4 per cent of the total liquid weight. Application of these normalized forces to actual size tank trucks further suggests that the rollover threshold acceleration of a rigidly suspended tank truck, due to sloshing, can be reduced by 2 per cent for the 98 per cent fill level, and around 10 per cent for the 90 per cent fill level. These already significant reductions in the roll stability of tank trucks would be more severe for a spring suspended vehicle, thus rationalizing the rollover trend of such vehicles. The use of longitudinal sloshing suppressors is strongly recommended.

Title: Active roll control of an experimental articulated vehicle

Author(s): A J P Miège; D Cebon

Source: Proceedings of the I MECH E Part D Journal of Automobile Engineering

Volume: 219 Page: 791 - 806. Feb 2005

DOI: 10.1243/095440705X28385

Publisher: Professional Engineering Publishing

Abstract: A new experimental articulated vehicle with computer-controlled suspensions is used to investigate the benefits of active roll control for heavy vehicles. The mechanical hardware, the instrumentation, and the distributed control architecture are detailed. A simple roll-plane model is developed and validated against experimental data, and used to design a controller based on lateral acceleration feedback. The controller is implemented and tested on the experimental vehicle. By tilting both the tractor drive axle and the trailer inwards, substantial reductions in normalised lateral load transfer are obtained, both in steady state and transient conditions. Power requirements are also considered.


Title: Comparative analysis for bus side structures and lightweight optimization

Author(s): F Lan; J Chen; J Lin

Source: Proceedings of the I MECH E Part D Journal of Automobile Engineering

Volume: 218 Page: 1067 - 1075. June 2004

DOI: 10.1243/0954407042274877

Publisher: Professional Engineering Publishing

Abstract: Lightweight structures in bus body design have been highlighted. In this investigation a new typical medium-sized bus body structure has been modelled and analysed using the computer aided design (CAD) package UG and finite element (FE) solver ANSYS. This paper presents a comparative analysis of two body side structures: with and without structural supporting members between the longitudinal waist beams of the side frames. Firstly, analysis of structure strength and stiffness for low-order vibration modes was carried out, and the effects of different structures on strength, rigidity and material use efficiency were examined. Corresponding experimentation was carried out to validate the simulation results. Secondly, sensitivity studies and structural optimization were performed to reduce body weight without losing overall strength and rigidity. Geometric parameters, including cross-sectional parameters and wall thickness, of large structural members are considered in the optimization. The results of the research provide a means of structural design optimization with consideration of bus body weight reduction.