Ahmed Soliman

Ceramic-based chemical sensors, probes and field-tests in automobile engines

The monitoring and control of combustion-related emissions is a top priority in many industries. The major methods used to detect combustion gases fall short of practical applications for in-situ measurements in industrial environments involving high temperature and chemical contaminants. The real challenge is not only to develop highly sensitive and selective sensors, but to maintain long-term stability in such aggressive environments. This article presents an overview of a multidisciplinary research effort in ceramic-based chemical sensors, highlighting opportunities as well as challenges. The group of sensors (CO, NOx, O2, and CO2) selected for this article can, in general, be used to determine the state of combustion in a wide variety of applications. Fabrication of sensor probes and their field-test results in automobile engines are also presented.

Diagnosis of an automotive emission control system using fuzzy inference

Abstract Fault diagnosis of a physical plant is crucial for its healthy performance, as it could ultimately prevent catastrophic failure, help comply with environmental regulations, and enhance customer satisfaction. There exist several methods to detect and isolate incipient faults that might cause a plant’s performance to deviate from the nominal, which can be either subjective or objective. A scheme and methodology for integrating subjective (heuristic) and objective (analytical) knowledge for fault diagnosis and decision-making using fuzzy logic is demonstrated in this paper. Furthermore, the structure, challenges, and benefits of such integration are explored. Also, experimental results of the work carried out are presented.

Development of Refuse Vehicle Driving and Duty Cycles

Research has been conducted to develop a methodology for the generation of driving and duty cycles for refuse vehicles in conjunction with a larger effort in the design of a hybrid-electric refuse vehicle. This methodology includes the definition of real-world data that was collected, as well as a data analysis procedure based on sequencing of the collected data into micro-trips and hydraulic cycles. The methodology then applies multi-variate statistical analysis techniques to the sequences for classification. Finally, driving and duty cycles are generated based on matching the statistical metrics and distributions of the generated cycles to the collected database. Simulated vehicle fuel economy for these cycles is also compared to measured values.

Vehicle chassis monitoring system

Abstract Fault detection and isolation is becoming one of the most important issues in vehicle control system design. The development of automotive systems shows an increasing integration of electronic sensors, microprocessors and actuators for improving the efficiency, reliability and performance of components as the engine, the suspension and the brakes, thus increasing the need for fault diagnosis. This paper presents the design of a new model-based fault diagnosis method for monitoring the vehicle chassis performance. A brake-by-wire system with electronic pedal and electrical brakes is considered in more detail showing the fault diagnosis methodology.

Model-Based Fault Diagnosis of a NOx Aftertreatment System

The Lean NOx Trap (LNT) is an aftertreatment device used to attain a reduction in nitrogen oxide emissions for Diesel and lean burn engines. The LNT is typically used as a storage device, capturing NOx during lean engine operation. The trap can be regenerated by controlling the exhaust air-fuel ratio to create a rich gas mixture. Under rich conditions, the stored NOx is released and catalytically converted. This way, tailpipe emissions can be significantly reduced by properly modulating the lean (storage) and rich (regeneration) periods. To maintain the LNT operate with high conversion efficiency, an optimized control of the regeneration scheduling is required. In addition, LNT systems require fault diagnostic schemes to detect and isolate faults, typically related to sulfur and thermal damages. This paper deals with the design and validation through simulation of a model-based fault diagnosis scheme for a LNT system. The mathematical model of the subsystem, based on the physics of the processes involved, consist of time- varying nonlinear ODEs. The proposed diagnostic approach is based on the generation of residuals using system models and through comparison of the predicted and measured value of selected variables, including the AFR, catalyst output temperature and the NOx concentration at the output of the LNT. The paper focuses on detection and isolation of controller faults and LNT parametric faults related to sulfur and thermal damage. The model utilized in the diagnostic scheme, which includes sulfur poisoning and thermal deactivation processes, has been experimentally validated from data collected on a Diesel LNT system and integrated with a quasi-steady engine and vehicle simulator to estimate tailpipe emissions during standard driving cycles.

An experimental study on engine dynamics model based in-cylinder pressure estimation

The information provided by the in-cylinder pressure signal is of great importance for modern engine management systems. The obtained information is implemented to improve the control and diagnostics of the combustion process in order to meet the stringent emission regulations and to improve vehicle reliability and drivability. The work presented in this paper covers the experimental study and proposes a comprehensive and practical solution for the estimation of the in-cylinder pressure from the crankshaft speed fluctuation. Also, the paper emphasizes the feasibility and practicality aspects of the estimation techniques, for the real-time online application. In this study an engine dynamics model based estimation method is proposed. A discrete-time transformed form of a rigid-body crankshaft dynamics model is constructed based on the kinetic energy theorem, as the basis expression for total torque estimation. The major difficulties, including load torque estimation and separation of pressure profile from adjacent-firing cylinders, are addressed in this work and solutions to each problem are given respectively. The experimental results conducted on a multi-cylinder diesel engine have shown that the proposed method successfully estimate a more accurate cylinder pressure over a wider range of crankshaft angles. Copyright

A Kalman-filter-based multi-sensor terrain profile measurement system: principle, implementation and validation

This paper discusses an improved design of vehicle-based mobile terrain profile measurement system that derives the terrain profile by combining information from several different sensors measuring distance, altitudes and position. The main challenge of the measurement system design is to derive the instantaneous dynamic motion of the platform vehicle in order to correct the direct profile elevation measurement from a set of laser optical sensors. By processing the velocity and attitude data from an Inertial Measurement Unit (IMU) and the absolute position data from a Global Positioning System (GPS), a Kalman Filter/Smoother algorithm is utilized in this sensor fusion application as a key step to obtain an accurate measurement of the platform vehicles dynamic motion. Through the implementation of this approach, not only is a high accuracy of measurement during short-time vehicle dynamic motion achieved, the algorithm also eliminates a sensor drift problem associated with the long term stability of the measurement system. The hardware and software prototype of this design have been implemented, and initial field tests show that the methodology has achieved good measurement accuracy.

Development of a terrain severity measurement system utilizing optical lasers

A terrain severity measurement system utilizing non-contact optical scanning laser technologies employed in on-road profiling has been developed to make detailed measurements of the relative smoothness of all types of terrain from paved roads to extreme off-road conditions. The objectives included operation in all climatic conditions, simplified operation, and rapid availability of data. Accelerometers and inclinometers are used to measure laser sensor movement in order to eliminate measurement errors due to vehicle pitch and roll. A GPS receiver is used to correlate terrain profile information to position and elevation data. The end result is an accurate description of the longitudinal and lateral terrain profile that can be used to characterize the terrain and within vehicle modeling and simulation programs.

Modeling, simulation, and concept design for hybrid-electric medium-size military trucks

A large scale design space exploration can provide valuable insight into vehicle design tradeoffs being considered for the U.S. Army’s FMTV (Family of Medium Tactical Vehicles). Through a grant from TACOM (Tank-automotive and Armaments Command), researchers have generated detailed road, surface, and grade conditions representative of the performance criteria of this medium-sized truck and constructed a virtual powertrain simulator for both conventional and hybrid variants. The simulator incorporates the latest technology among vehicle design options, including scalable ultracapacitor and NiMH battery packs as well as a variety of generator and traction motor configurations. An energy management control strategy has also been developed to provide efficiency and performance. A design space exploration for the family of vehicles involves running a large number of simulations with systematically varied vehicle design parameters, where each variant is paced through several different mission profiles and multiple attributes of performance are measured. The resulting designs are filtered to remove dominated designs, exposing the multi-criterial surface of optimality (Pareto optimal designs), and revealing the design tradeoffs as they impact vehicle performance and economy. The results are not yet definitive because ride and drivability measures were not included, and work is not finished on fine-tuning the modeled dynamics of some powertrain components. However, the work so far completed demonstrates the effectiveness of the approach to design space exploration, and the results to date suggest the powertrain configuration best suited to the FMTV mission.

The Development of a Terrain Severity Measurement System

The measurement of road profiles is useful for many purposes, from the determination of road conditions, to terrain mapping, and so on. There are systems in which the profile measurement is taken utilizing of non-contact laser scanning technologies. In such systems, the measurements are relative and are referred to a moving reference frame. These measurements require the knowledge of the moving reference frame, which can be extracted from inertial measurements. Typically, each of these sensors is provided with an accelerometer, and the vertical distance travelled by each sensor is calculated by integrating this accelerometer signal twice. In this work, the errors associated with the measurement of the terrain profile are analyzed in order to identify the main causes of measurement error as well as the overall accuracy of the terrain severity measurement system.© 2006 ASME