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Mathematical modelling has become an essential tool in the design of modern catalytic systems. Emissions legislation is becoming increasingly stringent, and so mathematical models of aftertreatment systems must become more accurate in order to provide confidence that a catalyst will convert pollutants over the required range of conditions. Automotive catalytic converter models contain several sub-models that represent processes such as mass and heat transfer, and the rates at which the reactions proceed on the surface of the precious metal. Of these sub-models, the prediction of the surface reaction rates is by far the most challenging due to the complexity of the reaction system and the large number of gas species involved.

Fuel economy has become an important consideration in forklift truck design, particularly in Europe. A simulation of the fuel consumption and performance of a forklift truck has been developed, validated and subsequently used to determine the energy consumed by individual powertrain components during drive cycles. The truck used in this study has a rated lifting capacity of 2500kg, and is powered by a 2.6 litre naturally aspirated diesel engine with a fuel pump containing a mechanical variable-speed governor. The drivetrain consisted of a torque convertor, hydraulic clutch and single speed transmission. AVL Cruise was used to simulate the vehicle powertrain, with coupled Mathworks Simulink models used to simulate the hydraulic and control systems and governor. The vehicle has been simulated on several performance and fuel consumption drive cycles with the main focus being the VDI 2198 fuel consumption drive cycle.

To maintain its relevance, motorsport cannot be exempt from the trend of increasing fuel economy. This bears obvious competitive benefits as well, either in decreasing the frequency of pit stops or the mass of fuel carried. Given the increased points weighting of fuel economy for the Formula Student (FS) competition, a complete analysis was performed on the Queen's Formula Racing 600cc motorcycle engine in preparation for the 2011 competition. The criteria for such high performance fuel economy differ to a degree from most mass transportation counterparts and were divided into three distinct regimes; full load, part load and no load conditions. Full load conditions naturally demand maximum torque for performance but that does not imply that fuel savings cannot be made whilst preserving this. The point at which maximum torque is produced with minimum air-fuel ratio, Leanest mixture for Best Torque (LBT), was therefore sought and mapped for full load.

An increase in global oil consumption, coupled with a peak in oil production, has seen the price of fuel escalate in recent years, and consequently the transport sector must take measures to reduce fuel consumption in vehicles. Similarly, ever-tightening emissions legislation is forcing automotive manufacturers to invest in technology to reduce toxic emissions. In response to these concerns, this project aims to address one of the fundamental issues with the Internal Combustion Engine - approximately one third of the fuel energy supplied to the engine is lost as heat through the exhaust system. The specific aim of this project is to reduce the fuel consumption of a diesel-electric hybrid bus by recovering some of this waste heat and converting it to useful power. This report details how turbocompounding can be applied to the engine, via the inclusion of a turbogenerator, and assesses its waste heat recovery performance.

In any internal combustion engine, the amount of heat rejected from the engine, and associated systems, is a result of the engine inefficiency. Successfully recovering a small proportion of this energy would therefore substantially improve the fuel economy. The Rankine Cycle system has been raising interest for its aptitude to produce systems capable of capturing part of this waste heat and regenerate it as electrical or mechanical power. By integrating these systems into existing hybrid engine environments, it has been proved that Rankine Cycle system, which is more than 150 years old, can play a major role in reducing fuel consumption. The use of such a system for waste heat recovery on a hybrid engine represents a promising compromise in transforming the thermal energy into electricity and feeding this electricity back to the vehicle drivetrain by using the in situ electrical motor system or storing it into batteries.

Computer simulation is now considered to be a crucial stage in the design of automotive catalysts due to the increasing complexity of modern aftertreatment systems. The resulting models almost invariably include surface reaction kinetics that are measured under controlled conditions similar to those found on a vehicle. Repeatability of the measurements used to infer surface reaction rates is fundamental to the accuracy of the resulting catalyst model. To achieve the required level of repeatability, it is necessary to ensure that the catalyst sample in question is stable and that its activity does not change during the test phase. It is therefore essential that the catalyst has been lightly aged, or "de-greened" before testing begins. It is also known that the state of the catalyst's surface prior to testing has an impact on its subsequent light-off performance and that test history can play an important role in catalyst activity.

Understanding the behavior of automotive catalysts formulations under the wide range of conditions characteristic of automotive applications is key to the design of present and future emissions control systems. Platinum-based oxidation catalysts have been in use for some time to treat the exhaust of diesel-powered vehicles and have, as part of an emissions control package, successfully enabled compliance with emissions legislation. However, progressively stringent legislated limits, coupled with the need to reduce vehicle manufacturing costs, is incessantly demanding the development of new and improved catalyst formulations for the removal of pollutants in the diesel exhaust. With the introduction of low sulfur diesel fuel, and the advantageous decline in Palladium prices with respect to Platinum, bimetallic Pt:Pd-based catalysts have found an application in diesel after treatment.

Flow maldistribution of the exhaust gas entering a Diesel Particulate Filter (DPF) can cause uneven soot distribution during loading and excessive temperature gradients during the regeneration phase. Minimizing the magnitude of this maldistribution is therefore an important consideration in the design of the inlet pipe and diffuser, particularly in situations where packaging constraints dictate bends in the inlet pipe close to the filter, or a sharp diffuser angle. This paper describes the use of Particle Image Velocimetry (PIV) to validate a Computational Fluid Dynamic (CFD) model of the flow within the inlet diffuser of a DPF so that CFD can be used with confidence as a tool to minimize this flow maldistribution. PIV is used to study the flow of gas into a DPF over a range of steady state flow conditions. The distribution of flow approaching the front face of the substrate was of particular interest to this study.

Restricting the flow rate of air to the intake manifold is a convenient and popular method used by several motor sport disciplines to regulate engine performance. This principle is applied in the Formula SAE and Formula Student competitions, the rules of which stipulate that all the air entering the engine must pass though a 20mm diameter orifice. The restriction acts as a partially closed throttle which generates a vacuum in the inlet plenum. During the valve overlap period of the cycle, which may be as much as 100 degrees crank angle in the motorcycle engines used by most FSAE competitors, this vacuum causes reverse flow of exhaust gas into the intake runners. This, in turn, reduces the amount of fresh air entering the cylinder during the subsequent intake stroke and therefore reduces the torque produced. This effect is particularly noticeable at medium engine speeds when the time available for reverse flow is greater than at the peak torque speed.

The objective of the study outlined in this paper was to optimize the performance of a 600cc four-cylinder FSAE engine through the use of one-dimensional simulation. The first step in this process was to validate a baseline model of the engine in its stock, unrestricted format. This was achieved through the use of crank-angle-resolved and cycle-averaged test data. The in-cylinder pressure history was also analyzed to provide combustion and friction data specific to this engine. This process significantly improved the correlation of the model with the test data and it was subsequently used to simulate and optimize the configuration of the engine planned for use in the 2008 FSAE competition. The process of validating the model, together with the specification of the subsequent optimized engine, are presented.

The adoption of each new level of automotive emissions legislation often requires the introduction of additional emissions reduction techniques or the development of existing emissions control systems. This, in turn, usually requires the implementation of new sensors and hardware which must subsequently be monitored by the on-board fault detection systems. The reliable detection and diagnosis of faults in these systems or sensors, which result in the tailpipe emissions rising above the progressively lower failure thresholds, provides enormous challenges for OBD engineers. This paper gives a review of the field of fault detection and diagnostics as used in the automotive industry. Previous work is discussed and particular emphasis is placed on the various strategies and techniques employed. Methodologies such as state estimation, parity equations and parameter estimation are explained with their application within a physical model diagnostic structure.

The use of inlet-restricted engines is commonplace in many motor sport applications and is particularly relevant for FSAE or Formula Student teams. The study outlined in this paper uses an engine simulation package, Virtual 4-Stroke, to predict the propagation of unsteady gas flow through an inlet-restricted 600cc four-stroke FSAE engine and hence optimise its geometry to maximise torque output. The Automated Design feature of the Virtual 4-Stroke package uses an intelligent Design-of-Experiments approach to obtain the optimum combination of a given set of geometric variables. This feature was used to find the engine configuration that maximises the torque output over the speed range 4000rpm to 12,000rpm. The variables investigated included the inlet pipe length, inlet plenum volume, inlet and exhaust camshaft opening time, duration and lift, with a total of 108 possible combinations.

Restricting the airflow to the engine is a convenient, and therefore common, method of regulating engine performance in many forms of motor sport. Formula SAE, and its European counterpart Formula Student, impose such restrictions on engine configuration. The capacity of the engines must not exceed 610cc but, more specifically to this study, the intake system must be fitted with a 20mm diameter restrictor through which all the air must pass. There are, however, a number of geometrical parameters which can be changed to maximise the performance of the restricted engine. In this study, the effects of modifying the restrictor design, intake runner length, intake camshaft profile, exhaust geometry, and silencer design were measured using a transient dynamometer. These tests were performed on a 600cc four-stroke, four-cylinder Yamaha YZF R6 engine.

This paper discusses the suitability of a 450 cm3, single-cylinder engine for use in the FSAE competition. The rules of the FSAE and Formula Student competitions permit the use of four-stroke engines of up to 610 cm3 capacity and with forced induction [1]. Most teams design cars around normally aspirated four-cylinder 600 cm3 engines. The suitability of an alternative single-cylinder engine is examined here through engine simulation. The simulation model of the single-cylinder engine is described and has been verified using published data on the engine's predecessor. This model is then used to find the most suitable configuration for use in the FSAE competition. It is shown that in a normally aspirated format, the single-cylinder engine is unlikely to be competitive. If supercharging is applied however, a very attractive overall vehicle package is found to result.

The geometrical design of the airbox for an internal combustion engine has a significant effect on the pressure loss in the entire inlet tract. Due to the location of the airbox, its size and shape is usually limited as a result of the proximity to other under-bonnet features. The shape is also limited by manufacturing, assembly and NVH considerations. The complexity of the unsteady flow through the airbox and the constraints placed upon it by the available volume in the under-bonnet area make this a challenging design task. This paper reviews the current thinking on methods used to optimize Computational Fluids Dynamics (CFD) problems and how this would apply to the optimization of an airbox for an internal combustion engine. The paper then goes on to detail the findings of the initial validation work on the CFD method for predicting the pressure loss through an airbox. An optimization case study is then presented based on one of the models used for the validation.

The incorporation of one-dimensional simulation codes within engine modelling applications has proved to be a useful tool in evaluating unsteady gas flow through elements in the exhaust system. This paper reports on an experimental and theoretical investigation into the behaviour of unsteady gas flow through catalyst substrate elements. A one-dimensional (1-D) catalyst model has been incorporated into a 1-D simulation code to predict this behaviour. Experimental data was acquired using a ‘single pulse’ test rig. Substrate samples were tested under ambient conditions in order to investigate a range of regimes experienced by the catalyst during operation. This allowed reflection and transmission characteristics to be quantified in relation to both geometric and physical properties of substrate elements.

A research project has been undertaken with the aim of characterizing and modeling the oxygen storage process in a three way automotive catalyst. The model consists of an oxygen storage sub-model and a kinetic reaction sub-model. Validation data for these models was recorded from a purpose-built catalyst flow reactor which uses O2 and NO as the oxidizing agents and CO, C3H6 and C3H8 as the reducing agents. The main focus of the work is the oxygen storage sub-model and the identification of the relevant constants for the reaction kinetic equations. The procedure used for measuring the oxygen storage capacity, and the oxygen storage and release rates from ceria (CeO2), is presented and discussed. The activation energies and activity factors for all the oxidation and reduction components were also found from the apparatus and used in the model.

The most common mode of deactivation suffered by catalysts fitted to two-stroke engines has traditionally been thermal degradation, or even meltdown, of the washcoat and substrate. The high temperatures experienced by these catalysts are caused by excessively high concentrations of HC and CO in the exhaust gas which are, in turn, caused by a rich AFR and the loss of neat fuel to the exhaust during the scavenging period. The effects of catalyst poisoning due to additives in the oil is often regarded as a secondary, or even negligible, deactivating mechanism in two-stroke catalysts and has therefore received little attention. However, with the introduction of direct in-cylinder fuel injection to some larger versions of this engine, the quantities of HC escaping to the exhaust can be reduced to levels similar to those found on four-stroke gasoline engines.

A technique has been developed to study the axial static pressure profile through the channels of a 400 cells per square inch (cpsi) catalytic converter monolith. The shape of the profile proved different from the accepted laminar flow profile, although the flow conditions are clearly laminar within the channels of the converter. The fact that the inner surfaces of the channels are extremely rough, and that this roughness is highly irregular, is thought to have an effect on the developed pressure profile. The measured profile was compared against the pressure profiles predicted by the most popular models in the published literature. A two-point criterion was developed to distinguish among those models. It was observed that Shah's model [1]* for the pressure drop along a square duct is the most appropriate. Additional static pressure measurements were taken both before and after the catalyst element and used to calculate the entrance and exit total pressure loss coefficients.

Due to stringent emissions legislation, the use of three way catalysts is becoming increasingly prevalent in motorcycles and scooters. This paper describes the development, and subsequent validation, of a detailed mathematical model for the oxygen storage processes in three-way catalysts. The model consists of several interdependent sub-models describing the oxidation and reduction processes and their interaction with a kinetic model of the catalyst. The structure and equations of the model are detailed and their significance discussed. For the validation phase of the work a purpose-built miniature catalyst test rig has been assembled and a series of experiments conducted to assess the oxygen storage processes. Analysis of this data also provided values for the controlling constants associated with the oxidation and reduction reactions. These results are included and compared with other published data.