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Reported in the current paper is a study of the effects of Nitric Oxide (NO) within a simulated Exhaust Gas Residual (sEGR) on Spark Ignition (SI) engine end gas autoignition. A modified version of the single cylinder Leeds University Ported Optical Engine Version 2 (LUPOE-2) engine was designed to completely eliminate retained residual gas and so allow unambiguous definition of the composition of the in-cylinder charge. The engine was alternately operated on stoichiometric mixtures of iso-octane, two Primary Reference Fuels (PRF), a Toluene Reference Fuel (TRF), and a commercially available Unleaded Gasoline (ULG) and air. These mixtures were diluted with sEGR (products of the complete stoichiometric combustion of the given fuel/air mixture) in mass fractions ranging from 0-15%; with and without 5000ppm NO (0.52% by mass) within that sEGR.

The paper discusses the concept, design and final results from the ‘Ultra Boost for Economy’ collaborative project, which was part-funded by the Technology Strategy Board, the UK's innovation agency. The project comprised industry- and academia-wide expertise to demonstrate that it is possible to reduce engine capacity by 60% and still achieve the torque curve of a modern, large-capacity naturally-aspirated engine, while encompassing the attributes necessary to employ such a concept in premium vehicles. In addition to achieving the torque curve of the Jaguar Land Rover naturally-aspirated 5.0 litre V8 engine (which included generating 25 bar BMEP at 1000 rpm), the main project target was to show that such a downsized engine could, in itself, provide a major proportion of a route towards a 35% reduction in vehicle tailpipe CO2 on the New European Drive Cycle, together with some vehicle-based modifications and the assumption of stop-start technology being used instead of hybridization.

A Gas to liquid (GTL) fuel was investigated for its combustion and emission performance in an IVECO EURO5 DI diesel engine with a DOC (Diesel Oxidation Catalyst) and DPF (Diesel Particle Filter) installed. The composition of the GTL fuel was analyzed by GC-MS (gas chromatography-mass spectrometry) and showed the carbon distribution of 8-20. Selected physical properties such as density and distillation were measured. The GTL fuel was blended with standard fossil diesel fuel by ratios of diesel/GTL: 100/0, 70/30, 50/50, 30/70 and 0/100. The engine was equipped with a pressure transducer and crank angle encoder in one of its cylinders. The properties of ignition delay and maximum in-cylinder pressure were studied as a function of fraction of the GTL fuel. Particle emissions were measured using DMS500 particle size instrument at both upstream (engine out) and downstream of the DPF (DPF out) for particle number concentrations and size distribution from 5 nm to 1000 nm.

Due to the variability of real traffic conditions for vehicle testing, real-world vehicle performance estimation using simulation method become vital. Especially for heavy duty vehicles (e.g. 40 t trucks), which are used for international freight transport, real-world tests are difficult, complex and expensive. Vehicle simulations use mathematical methods or commercial software, which take given driving cycles as inputs. However, the road situations in real driving are different from the driving cycles, whose speed profiles are obtained under specific conditions. In this paper, a real-world vehicle performance estimation method using simulation was proposed, also it took traffic and real road situations into consideration, which made it possible to investigate the performance of vehicles operating on any roads and traffic conditions. The proposed approach is applicable to all kind of road vehicles, e.g. trucks, buses, etc. In the method, the real-road network includes road elevation.

Heat Release Rate (HRR) analysis is indispensable in engine research. The HRR of Internal Combustion Engines (ICEs) is most sensitive to gamma (γ). The proposed HRR models in literature were largely based on γ expressed as functions of temperature. However, γ is depended on temperature as well as the excess air ratio (λ). In this work, an improved HRR model based on γ(T, λ) was used to investigate the combustion behaviour of standard diesel, Gas-to-Liquid (GTL) diesel and Hydrotreated Vegetable Oil (HVO) diesel in a 96 kW, multiple fuel injection, Euro V, Direct Injection (DI) engine. The improved HRR model (Leeds HRR model) was validated for the alternative fuels by comparing the fuel masses predicted by the model to the measured fuel masses. The fuel masses predicted by the Leeds HRR model were also compared to the predictions from four HRR models that were based on γ(T).

This paper proposes an advanced control strategy to improve vehicle handling and directional stability by integrating either Active Front Steering (AFS) or Active Rear Steering (ARS) with Variable Torque Distribution (VTD) control. Both AFS and ARS serve as the steerability controller and are designed to achieve the improved yaw rate tracking in low to mid-range lateral acceleration using Sliding Mode Control (SMC); while VTD is used as the stability controller and employs differential driving torque between left and right wheels on the same axle to produce a relatively large stabilizing yaw moment when the vehicle states (sideslip angle and its angular velocity) exceed the reference stable region defined in the phase plane. Based on these stand-alone subsystems, an integrated control scheme which coordinates the control actions of both AFS/ARS and VTD is proposed. The functional difference between AFS and ARS when integrated with VTD is explained physically.

The detailed, dynamic properties of dampers are known to influence substantially some of the subtle - and yet nevertheless hugely important - refinement aspects or ride and handling. Despite this, most of the current work on damping characterization relies on steady-state properties and transient aspects are left largely to subjective in-car assessments by test drivers. The paper describes research work aimed at improving our understanding of the transient properties of dampers through mathematical modeling and then attempting to link these properties to detailed aspects of the vehicle ride and handling. Further experimental work is planned to follow later. From a moderately complex mathematical model of a damper, an attempt is made to identify (a) those transient characteristics which are important in influencing the vehicle responses perceived by test drivers, and (b) which design features of the damper control those characteristics.

In this paper a gearshift controller for twin clutch transmissions is developed. The controller incorporates the control of engine variables to achieve synchronization whilst the transfer of engine torque from clutch to clutch is managed by a clutch slip control. On top of this gearshift controller and as an extension to the basic control scheme a transmission output torque control is included as a means to directly influence shift character and add robustness to the control. The transmission output torque control also provides the foundation for an integrated torque management scheme of powertrain components. Simulation results for upshift and downshift are presented and discussed in the final chapter of this paper.

A number of handling models of a small high performance formula type racing car have been produced. These have been used to optimise the performance of the vehicle whilst under going simple manoeuvres and around a complete race track. Recently the vehicle was fitted with a data acquisition system and objective data was taken of the vehicle's handling performance. The paper details an investigation into the accuracy of two (a simple and more sophisticated) vehicle handling models in predicting the actual vehicle's performance from the data collected by comparing measured and simulated results. The investigation studies the steady state and transient response of the vehicle up to the limit of the vehicle's handling performance. A description is also given of the use of the more sophisticated model in a virtual race track simulation where it is used as a development tool to tune the performance of future vehicles.

This paper presents a method of control for a 6×6 series-configured Hybrid Electric Off-road Vehicle (HEOV). The vehicle concerned is an eight-tonne logistics support vehicle which utilizes Hub Mounted Electric Drives (HMED) at each of its six wheel stations. This set-up allows Individual Wheel Control (IWC) to be implemented to improve vehicle handling and mobility. Direct Yaw-moment Control (DYC) is a method of regulating individual wheel torque to control vehicle yaw motion, providing greater stability in cornering. When combined with both a Traction Control System (TCS) and an Anti-lock Braking System (ABS) the tire/road interaction is fully controlled, leading to improved control over vehicle dynamics, whilst also improving vehicle safety.

Motion cueing algorithms can improve the perceived realism of a driving simulator, however, data on the effects on driver performance and simulator sickness remain scarce. Two novel motion cueing algorithms varying in concept and complexity were developed for a limited maneuvering workspace, hexapod/Stuart type motion platform. The RideCue algorithm uses a simple swing motion concept while OverTilt Track algorithm uses optimal pre-positioning to account for maneuver characteristics for coordinating tilt adjustments. An experiment was conducted on the US Army Tank Automotive Research, Development and Engineering Center (TARDEC) Ride Motion Simulator (RMS) platform comparing the two novel motion cueing algorithms to a pre-existing algorithm and a no-motion condition.

Fluctuations in the operational output of spark ignition engines are observed from one engine cycle to the other, when an engine is run at technically identical operating condition. These fluctuations known as cycle-to-cycle variations, when high, adversely affect the performance of an engine. Reduction in cycle-to-cycle variation in engines has been noted by researchers as one of the methods of improving engine efficiency and operational stability. This study investigated the combustion performance characteristics of two fuels: E5 (95% gasoline and 5% ethanol) and ULG98 (unleaded gasoline) in a spark ignition engine, operating at varying inlet pressure conditions and ignition timing. A two-stroke, 80mm bore, spark ignition engine was operated at an engine speed of 750 rpm, inlet pressures of 1.6 and 2.0 bar and spark-timings ranging from 2 to 13 bTDC. A top cylinder head with a centralized spark plug was used in all the experiments.

The Swedish Biomimetics 3000's μMist® platform technology has been used to develop a radically new injection system. This prototype system, developed and characterized with support from Lotus, as part of Swedish Biomimetics 3000®'s V₂IO innovation accelerating model, delivers improved combustion efficiency through achieving exceptionally small droplets, at fuel rail pressures far less than conventional GDI systems and as low as PFI systems. The system gives the opportunity to prepare and deliver all of the fuel load for the engine while the intake valves are open and after the exhaust valves have closed, thereby offering the potential to use advanced charge scavenging techniques in PFI engines which have hitherto been restricted to direct-injection engines, and at a lower system cost than a GDI injection system.

Small diesel engines are a common primer for micro and mini-grid systems, which can supply affordable electricity to rural and remote areas, especially in developing countries. These diesel generators have no exhaust after-treatment system thus exhaust emissions are high. This paper investigates the potential of introducing simulated synthetic gas (syngas) to diesel in a small diesel engine to explore the opportunities of widening fuel choices and reducing emissions using a 5.7kW single cylinder direct injection diesel generator engine. Three different simulated syngas blends (with varying hydrogen content) were prepared to represent the typical syngas compositions produced from downdraft gasification and were injected into the air inlet. In-cylinder pressure, ignition delay, premixed combustion, combustion stability, specific energy consumption (SEC), and gaseous and particle emissions were measured at various power settings and mixing ratios.

Numerical investigations are reported on the location of sites at which autoignition first develops in the end-gas ahead of a spark-ignited flame in a combustion chamber following rapid compression of an alkane + air mixture to high pressures and temperatures. Attention is drawn to the part played by the reactions that give rise to a negative temperature coefficient of reaction rate in an inhomogeneous temperature field. A ‘reduced’ kinetic mechanism was employed to model the spontaneous oxidation of n-alkanes. Flame propagation was described in terms of the ‘eddy dissipation concept’ and coupled to the more detailed mechanism by means of a switching algorithm. The CFD calculations were performed by use of KIVA II.

A 3-zone thermodynamic cycle model has been developed which incorporates the Leeds correlations of turbulent burning velocity. The correlations encompass both the beneficial effects of turbulence in flame wrinkling and the detrimental effects of flame strain, which can lead to partial or total flame quench. Allowance has been made for the effects of “developing turbulence”, as the initially laminar flame kernel grows and is progressively influenced by larger scales of turbulence. Available experimental cylinder pressure and flame propagation data were used to check the plausibility of the simulation code and to establish values for the various constants employed to characterize the turbulence. The program was then used to explore the effects of engine speed, mixture strength, induction pressure and turbulence levels on the development of the combustion event.

A 2-D simulation of fluid dynamic and chemistry interaction following end gas autoignition has demonstrated three distinct modes of reaction, dependent upon the temperature gradient about an exothermic centre. All three modes (deflagration, developing detonation and thermal explosion) can contribute to knock; the developing detonation case, associated with intermediate temperature gradient, has been identified as the more damaging. The simulation code (LUMAD) has been used in a systematic parametric study designed to separate the complex interacting events which can lead to mixed modes in real engines. A most significant finding related to the sequential autoignition of multiple exothermic centres.

A non-linear example vehicle model including four degrees of freedom (yaw, sideslip, roll and steering), non-linear kinematics and the Magic Formula tyre model has been developed. With the assumption of small perturbations around any steady-state working condition, the linearised equations are derived. A novel approach is used for the linearisation of external forces and moments from the tyres. They are linearised in terms of the state variables rather than the slip angle, camber angle and vertical load which are themselves functions of the state variables. The results of this process are expressed in terms of stability derivatives. In order to use the method, the steady-state solution of the non-linear equations is first obtained for a particular value of lateral acceleration, then after the calculation of the stability derivatives, a linear analysis can be performed for the linear equations in terms of perturbed variables.

A non-contacting laser displacement meter has been used for dynamic measurements of the radial movement of a v-ribbed belt (type 3PK) around the arc of wrap running on a belt testing rig. Accurate and repeatable results are possible. Using this device, the belt radial movement and the beginning of rib bottom / groove tip contact around the arc of wrap have been determined experimentally for v-ribbed belts. Slip, torque loss, maximum torque capacity and efficiency have been measured during the tests.

This paper reports the results of a back-to-back comparison of the squeal and judder propensity of simple cast iron and siliconised carbon disk brake systems. A finite element simulation approach is used to predict the squeal propensity of the two systems based on the results of a complex eigenvalue analysis. These results which are validated by dynamometer noise tests carried out according to the SAE J2521 [1] standard procedure show that the siliconised carbon rotor is much less prone to squeal over the range of conditions considered. The combined experimental and numerical simulation approach is also applied to the problem of hot judder for the two rotors. The critical rotational speeds for hot spots to form are predicted to be an order of magnitude higher for the siliconised carbon rotor system. These results demonstrate the potential of the new carbon composite rotor material to reduce the occurrence of noise and vibration problems in automotive brakes.