Viewing 1 to 9 of 9
Technical Paper
Philip John Roberts, Alexandros Kountouriotis, Pawel Okroj, Pavlos Aleiferis, Brian Cooper
Reported in the current paper is a study into the cycle efficiency effects of utilising a complex valvetrain mechanism in order to generate variable in-cylinder charge motion and therefore alter the dilution tolerance of a Direct Injection Spark Ignition (DISI) engine. A Jaguar Land Rover Single Cylinder Research Engine (SCRE) was operated at a number of engine speeds and loads with the dilution fraction varied accordingly (excess air (lean), external Exhaust Gas Residuals (EGR) or some combination of both). For each speed, load and dilution fraction, the engine was operated with either both intake valves fully open – Dual Valve Actuation (DVA) – or one valve completely closed – Single Valve Actuation (SVA) mode. The engine was operated in DVA and SVA modes with EGR fractions up to 20% with the excess air dilution (Lambda) increased (to approximately 1.8) until combustion stability was duly compromised.
Technical Paper
Louis Nicholson, Xiaohang Fang, Joseph Camm, Martin Davy, David Richardson
Accurate modeling of the initial transient period of spray development is critical within diesel engines, as it impacts on the amount of vapor penetration and hence the combustion characteristics of the spray. In addition, in multiple injection schemes shorter injections will be mostly, if not totally, within the initial transient period. This paper investigates how two different commercially available Computational Fluid Dynamics (CFD) codes (hereafter noted as Code 1 and Code 2) simulate transient diesel spray atomization, in a non-combusting environment. The case considered for comparison is a single-hole injection of n-dodecane representing the Engine Combustion Network’s ‘Spray A’ condition. It was identified that the different break-up models used by the codes (Reitz-Diwakar for Code 1, KH-RT for Code 2) had a significant impact on the transient liquid penetration. From differing initial base setups, Code 1’s case was matched as closely as possible to Code 2’s case.
Technical Paper
Alexandros Plianos, Tommi Jokela, Matthew Hancock
Vehicle energy management strategies main objective is to optimise the vehicle overall energy consumption and minimise harmful emissions. As vehicles become increasingly connected and gain access to larger amounts of information in relation to their surroundings and the road ahead, the potential benefit from predictive energy optimization (PEO) schemes increases. Such schemes attempt to predict future road events to enable the vehicle energy management to save energy by preparing for these events preemptively. An important parallel current trend is the development of Vehicle-to-X (V2X) communications which is expected to become a standard technology in the coming years. First applications of V2X have focused on increasing safety and convenience.
Journal Article
Blane Scott, Christopher Willman, Ben Williams, Paul Ewart, Richard Stone, David Richardson
Abstract In-cylinder temperature measurements are vital for the validation of gasoline engine modelling and useful in their own right for explaining differences in engine performance. The underlying chemical reactions in combustion are highly sensitive to temperature and affect emissions of both NOx and particulate matter. The two techniques described here are complementary, and can be used for insights into the quality of mixture preparation by measurement of the in-cylinder temperature distribution during the compression stroke. The influence of fuel composition on in-cylinder mixture temperatures can also be resolved. Laser Induced Grating Spectroscopy (LIGS) provides point temperature measurements with a pressure dependent precision in the range 0.1 to 1.0 % when the gas composition is well characterized and homogeneous; as the pressure increases the precision improves.
Technical Paper
Safwan Hanis Mohd Murad, Joseph Camm, Martin Davy, Richard Stone, Dave Richardson
Model M15 gasoline fuels have been created from pure fuel components, to give independent control of volatility, the heavy end content and the aromatic content, in order to understand the effect of the fuel properties on Gasoline Direct Injection (GDI) fuel spray behaviour and the subsequent particulate number emissions. Each fuel was imaged at a range of fuel temperatures in a spray rig and in a motored optical engine, to cover the full range from non-flashing sprays through to flare flashing sprays. The spray axial penetration (and potential piston and liner impingement), and spray evaporation rate were extracted from the images. Firing engine tests with the fuels with the same fuel temperatures were performed and exhaust particulate number spectra captured using a DMS500 Mark II Particle Spectrometer.
Technical Paper
Petros Efthymiou, Colin P. Garner, Graham K. Hargrave, David Richardson
Particulate number (PN) standards in the current ‘Euro 6’ European emissions standards pose a challenge for engine designers and calibrators during the warm-up phases of cold direct injection spark ignition (DISI) engines. To achieve catalyst light-off in the shortest time, engine strategies are often employed which inherently use more fuel to attain higher exhaust temperatures. This can lead to the generation of locally fuel-rich regions within the combustion chamber and the emission of particulates. This investigation analyses the combustion structures during the transient start-up phase of an optical DISI engine. High-speed, colour 9 kHz imaging was used to investigate five important operating points of an engine start-up strategy whilst simultaneously recording in-cylinder pressure.
Technical Paper
Sajeev Silvester, Alex Lakic, Michael Buckley
Abstract Dimensional distortion, cosmetic distortion issues can arise during heating and cooling in the paint shop processing of car bodies. A car body can be in perfect cosmetic condition as it leaves the BIW facility, yet develop distortion defects during painting. Traditionally such issues have only been detectable on new car body designs by building and painting prototypes of a new design. The timing of such activities, by their very nature, mean that precious little time is available to address these issues by design changes in today's condensed new vehicle programmes. The result is often a vehicle entering production with partial resolution of an issue, accompanied by on-going product rework and rectification activities throughout the lifecycle of the product. This created the need for developing a CAE simulation tool which could predict these issues very early during the virtual CAE build phases of a vehicle program itself.
Journal Article
Karl Dearn, Jiyuan Xu, Haichun Ding, Hongming Xu, Adam Weall, Phil Kirkby, Brian Cooper, Ian Edington, Jens Krueger-Venus
Abstract There is an increasing recognition of injector deposit (ID) formation in fuel injection equipment as direct injection spark ignition (DISI) engine technologies advance to meet increasingly stringent emission legislation and fuel economy requirements. While it is known that the phenomena of ID in DISI engines can be influenced by changes in fuel composition, including increasing usage of aliphatic alcohols and additive chemistries to enhance fuel performance, there is however still a great deal of uncertainty regarding the physical and chemical structure of these deposits, and the mechanisms of deposit formation. In this study, a mechanical cracking sample preparation technique was developed to assess the deposits across DISI injectors fuelled with gasoline and blends of 85% ethanol (E85).
Technical Paper
Mohammed Reza Kianifar, Felician Campean, David Richardson
This paper presents a calibration optimization study for a Gasoline Direct Injection engine based on a multidisciplinary design optimization (MDO) framework. The paper presents the experimental framework used for the GDI engine mapping, followed by an analysis of the calibration optimization problem. The merits of the MDO approach to calibration optimization are discussed in comparison with a conventional two-stage approach based on local trade-off optimization analysis, focused on a representative emissions drive cycle (NEDC) and limited part load engine operation. The benefits from using the MDO optimisation framework are further illustrated with a study of relative effectiveness of different camshaft timing control strategies (twin independent Versus fixed timing, exhaust only, inlet only and fixed overlap / dual equal) for the reference GDI engine based on the part load test data.
Viewing 1 to 9 of 9


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