Viewing 1 to 30 of 57
Technical Paper
Chi La, Marco Poggi, Patrick Murphy, Ondrej Zitko
In response to environmental and fossil fuel usage concerns, the automotive industry will gradually move from Hybrid Electric Vehicles (HEV) which includes a shift of internal combustion engines toward Zero Emissions Vehicles (ZEV). Refinement is an important aspect in the successful adoption of any new technology and ZEV brings its own NVH challenges owing to the unique dynamic characteristics of the powertrain and driveline system. This paper presents considerations for addressing dynamic driveline NVH issues that are common to 100% electric vehicles; issues that manifest themselves as groans, rattles and clunks. A dynamic torsional analytical model of the powertrain & driveline will be presented. The analytical model served as the baseline for an extensive parametric study using the Genetic Algorithm (GA) technique, whereby the effectiveness of practical countermeasures was investigated.
Journal Article
M. Yusri Yusof, Fadhlan Nik Abdul Aziz, M. Faizan Zuhdi, Phil Carden, David Bell
The authors have published SAE paper 2008-01-0088 on the analytical comparison between 4 and 8 counterweight crankshafts for an I4 gasoline engine. This paper showed that for a particular design of a 4 counterweight crankshaft, the differences in bearing force and oil film thickness were very small and the only major difference in terms of bearing shaft tilt angle occurred at mains 2 and 4 (increase of ∼20% compared with 8 counterweight version). The 4 counterweight crankshaft has a significant mass advantage as it was 1.42kg lighter than the 8 counterweight crankshaft. This new paper addresses the testing performed to validate the analysis results in bearing durability by subjecting the engine to a mixture of high speed and general durability cycles. A comparison was made on the bearing conditions after running a total of 100 hours through prescribed durability cycles on a gasoline engine with both 4 and 8 counterweight crankshafts.
Technical Paper
Luke Cruff, Michele Kaiser, Steven Krause, Roderick Harris, Uwe Krueger, Matthew Williams
The Ethanol-Boosted Direct Injection (EBDI) demonstrator engine is a collaborative project led by Ricardo targeted at reducing the fuel consumption of a spark-ignited engine. This paper describes the design challenges to upgrade an existing engine architecture and the synergistic use of a combination of technologies that allows a significant reduction in fuel consumption and CO₂ emissions. Features include an extremely reduced displacement for the target vehicle, 180 bar cylinder pressure capability, cooled exhaust gas recirculation, advanced boosting concepts and direct injection. Precise harmonization of these individual technologies and control algorithms provide optimized operation on gasoline of varying octane and ethanol content.
Technical Paper
J. Stokes, T. H. Lake, R. D. Murphy, R. J. Osborne, J. Patterson, J. Seabrook
This paper describes the results of the first stage of an integrated experimental and modelling programme on a gasoline engine with Twin Mechanical Variable Lift (TMVL) capability. The engine used for this work was a modified version of a 4 cylinder, 2.0 litre BMW engine. The modified engine has the “Valvetronic” continuously variable lift valvetrain on both the inlet and exhaust valves and dual independent cam phasers with 60 crankshaft degrees of phasing authority. The Valvetronic system allows continuous variation of the valve lift from a minimum of 0.25 mm to a maximum of 9.7 mm.
Technical Paper
S. R. Anderson, D. M. Lamberson, T. J. Blohm, W. Turner
This paper describes the application of a systematic methodology to the exploratory investigation of fuel economy for a heavy-duty route vehicle with a hybrid powertrain. The analytical study considered parallel hydraulic hybrid, parallel electric and series electric hybrid architectures in addition to the baseline conventional powertrain. The real world driving mission for the target vehicle, a domestic refuse collection truck, was clarified by making vehicle measurements. System simulation was then used as a key tool to support the fuel economy predictions and trade studies.
Technical Paper
A. M. Greaney, A. J. Beaumont, A. D. Noble
The inherent fuel economy benefits of diesel powertrains over gasoline offer significant potential for reduced energy consumption and provide vehicle manufacturers with a viable method of improving Corporate Average Fuel Economy (CAFE). However, achieving the stringent NOx emission levels of upcoming LEV II and Tier 2 standards, while retaining low fuel consumption and satisfying consumer demand for higher performance, presents significant technical challenges. For diesel powertrains to succeed in the US light duty vehicle market, manufacturers must apply engine and exhaust aftertreatment technologies which meet the technical demands within a viable business case. This paper outlines the trends in advanced electronics and controls for diesel powertrains and the role of these technologies in enabling diesel as a viable fuel efficient option for the US light duty vehicle market.
Technical Paper
R. Lockett, Mahesh Jeshani, Kassandra Makri, Richard Price
Abstract High-speed planar laser Mie scattering and Laser Induced Fluorescence (PLIF) were employed for the determination of Sauter Mean Diameter (SMD) distribution in non-evaporating diesel sprays. The effect of rail pressure, distillation profile, and consequent fuel viscosity on the drop size distribution developing during primary and secondary atomization was investigated. Samples of conventional crude-oil derived middle-distillate diesel and light distillate kerosene were delivered into an optically accessible mini-sac injector, using a customized high-pressure common rail diesel fuel injection system. Two optical channels were employed to capture images of elastic Mie and inelastic LIF scattering simultaneously on a high-speed video camera at 10 kHz. Results are presented for sprays obtained at maximum needle lift during the injection. These reveal that the emergent sprays exhibit axial asymmetry and vorticity.
Journal Article
Peter Fussey, David Limebeer
Abstract The introduction of transient test cycles and the focus on real world driving emissions has increased the importance of ensuring the NOx and soot emissions are controlled during transient manoeuvres. At the same time, there is a drive to reduce the number of calibration variables used by engine control strategies to reduce development effort and costs. In this paper, a control orientated combustion model, [1], and model predictive control strategy, [2], that were developed in simulation and reported in earlier papers, are applied to a Diesel engine and demonstrated in a test vehicle. The paper describes how the control approach developed in simulation was implemented in embedded hardware, using an FPGA to accelerate the emissions calculations. The development of the predictive controller includes the application of a simplified optimisation algorithm to enable a real-time calculation in the test vehicle.
Technical Paper
Konstantinos Michos, Georgios Bikas, Ioannis Vlaskos
Abstract A new global NOx emissions formation model, formulated by a single analytically derived algebraic equation, is developed with relevance to post-flame gases. The model originates from subsets of detailed kinetic schemes for thermal and N2O pathway NO formation, needs no calibration and is quick to implement and run. Due to its simplicity, the model can be readily used in both 1D and 3D-CFD simulation codes, as well as for direct post-processing of engine test data. Characteristic timescales that describe the kinetic nature of the involved NO formation routes, when they evolve in the post-flame gases independently the one from another, are introduced incorporating kinetic information from all relevant elementary reactions.
Technical Paper
Jonathan Plail, Petr Grinac, Helen Ballard
Abstract In this paper, a mathematical model for simulating the 3D dynamic response of a valve spring is described. The 3D model employs a ‘geometrically exact’ 3D beam connected between each mass of the discretised mass-elastic system. Shear deformations within the beam are also considered, which makes it a Timoshenko type finite element. Results from the 3D model are compared with results from a more conventional 1D model. To validate the results further, some results are compared with real test data that was gathered during a technical consulting project. In this project, a prototype valvetrain that was originally giving acceptable durability began to wear the spring seats when a new batch of springs were procured and tested. 1D and 3D simulation results were used to help understand the cause of the failure and to make recommendations to resolve the issue. Results showed that the 3D model was able to predict the spring seat loads with greater precision than the 1D spring could.
Technical Paper
Jiri Navratil, Warren Seeley, Peng Wang, Shriram Siravara
Abstract The ability to accurately predict exhaust system acoustics, including transmission loss (TL) and tailpipe noise, based on CAD geometry has long been a requirement of most OEM’s and Tier 1 exhaust suppliers. Correlation to measurement data has been problematic under various operating conditions, including flow. This study was undertaken to develop robust modelling technique, ensuring sensible correlation between the 1-D models and test data. Ford use Ricardo WAVE as one of their 1-D NVH tools, which was chosen for the purpose of this benchmark study. The most commonly used metrics for evaluating the acoustical performance of mufflers are insertion loss (IL), TL, and noise reduction (NR). TL is often the first step of analysis, since it represents the inherent capability of the muffler to attenuate sound if both the source and termination are assumed to be anechoic. It can also be reliably measured and numerically simulated without having to connect to an engine.
Technical Paper
F. Bérard, A. Cotta, J. Stokes, R. Thring, J. Wheals
The need to reduce fuel consumption and CO2 emissions while meeting future emission legislation has lead to the investigation of alternative engines, transmissions, aftertreatment and control strategies. The evaluation of alternative configurations at the concept stage requires vehicle drive cycle simulation tools, which include the following features: Fast run-time Alternative transmission models Cold start effects on fuel consumption and emissions modeled After-treatment models. This paper describes the development of a MATLAB/SIMULINKTM - based drive cycle simulation model meeting these requirements. The paper includes validation data comparing fuel consumption, engine-out and tailpipe emissions for a direct injection gasoline vehicle with a stoichiometric/lean switching strategy and lean NOx catalyst.
Technical Paper
J. Stokes, T. H. Lake, R. J. Osborne
This paper describes the Lean Boost System, a gasoline engine concept for improved fuel economy. The system combines direct injection, lean operation and pressure charging, and allows significant reduction in swept volume, or ‘downsizing’. Engine tests have been undertaken which demonstrate the validity of the combustion concept. The strategy a typical manufacturer might adopt in order to meet future European requirements for CO2 emissions is proposed. Vehicle simulation results for typical North American and European vehicles are presented. Using the exhaust gas emission levels from engine tests and drive cycle simulation, aftertreatment requirements and configurations are considered.
Technical Paper
Martin Gold, John Stokes, Robert Morgan, Morgan Heikal, Guillaume de Sercey, Steve Begg
For optimum efficiency, the direct injection (DI) gasoline engine requires two operating modes to cover the full load/speed map. For lower loads and speeds, stratified charge operation can be used, while homogeneous charge is required for high loads and speeds. This paper has focused its attention on the latter of these modes, where the performance is highly dependent on the quality of the fuel spray, evaporation and the air-fuel mixture preparation. Results of quantitative and qualitative Laser Induced Fluorescence (LIF) measurements are presented, together with shadow-graph spray imaging, made within an optically accessed DI gasoline engine. These are compared with previously acquired air flow measurements, at various injection timings, and with engine performance and emissions data obtained in a fired single cylinder non-optical engine, having an identical cylinder head and piston crown geometry.
Technical Paper
David Kelly Christopher Kent
The importance of the gear shift quality of manual transmissions has increased significantly over the past few years as the refinement of other vehicle systems has increased. The synchroniser is often blamed as the cause of many shift quality issues. This is not always the case. The interaction of the entire selector system from the shift fork to the handball, the driveline and the transmission internals all play a part in the overall shift quality. The dynamic interaction of these systems at a component level is difficult to interpret by traditional test methods and virtually impossible at concept stage. To overcome these difficulties a dynamic model of the entire synchroniser, selector mechanism, driveline and transmission has been created. The model predicts the gearshift quality for a given set of input parameters, which can be correlated against test data. The model can then be used for parameter studies to investigate potential improvements to gearshift quality.
Technical Paper
R. Morgan, J. Wray, D. A. Kennaird, C. Crua, M. R. Heikal
The influences of injector nozzle geometry, injection pressure and ambient air conditions on a diesel fuel spray were examined using back-lighting techniques. Both stills and high speed imaging techniques were used. Operating conditions representative of a modern turbocharged aftercooled HSDI diesel engine were achieved in an optical rapid compression machine fitted with a common rail fuel injector. Qualitative differences in spray structure were observed between tests performed with short and long injection periods. Changes in the flow structure within the nozzle could be the source of this effect. The temporal liquid penetration lengths were derived from the high-speed images. Comparisons were made between different nozzle geometries and different injection pressures. Differences were observed between VCO (Valve Covers Orifice) and mini-sac nozzles, with the mini-sac nozzles showing a higher rate of penetration under the same conditions.
Technical Paper
M. Sadler, A.J. Stapleton, R.P.G. Heath, N.S. Jackson
If fuel cell vehicles are to compete in the same marketplace as conventional vehicles, then they must provide the consumer with the same, or improved, levels of convenience, comfort, refinement and performance at the same, or lower, price. In 2003/4, several vehicle manufacturers are planning to launch their first commercial fuel cell vehicles onto the market. In this remarkably short timeframe, many systems must be integrated into a vehicle including the fuel cell system plus thermal and water management, cabin heating, ventilation and air-conditioning, control and on-board diagnostics, power electronics, electric motor and gearbox, suspension, steering, braking, refinement and crash protection. This paper presents a range of modelling techniques which allow the user to design and develop key systems, including the power management system, compressed air supply, thermal management and control algorithms.
Technical Paper
R. J. Osborne, G. Li, S. M. Sapsford, J. Stokes, T. H. Lake, M. R. Heikal
This paper describes a two-year programme of research conducted by the authors investigating HCCI in direct injection gasoline engines. Poppet-valved two-stroke cycle operation has been investigated experimentally, using conventional gasoline compression ratios and fuel, and ambient temperature intake air. Extensive combustion and emissions data was gathered from the experimental engine. Computational Fluid Dynamics (CFD) has been used to model HCCI combustion, and the CFD tool validated using experimental data. Based on experience with the two-stroke engine and modelling techniques, a four-stroke engine has been designed and tested. Using this range of tools, practical options for gasoline HCCI engines are evaluated, and a scenario for the market introduction of HCCI is presented.
Ricardo and partners have completed testing on a prototype engine designed to switch between two- and four-stroke modes.
For design teams focused on aftertreatment, removing size has become almost as important as removing emissions. Combining catalysts, improving filters and integrating sensors are a few of the techniques being used to minimize package sizes.
Biofuel research continues to advance as off-highway engineers develop new techniques that will let engines run on varying mixtures.
Ricardo Inc. formed a strategic business alliance with XRD Inc. (XRDi) and NW UAV to design, develop, and manufacture a family of heavy-fuel engine solutions for unmanned systems. Branded Wolverine, the new engine line combines Ricardo's engineering expertise with XRDi's propriety combustion technology and NW UAV's advanced manufacturing capabilities.
With continuing pressure to increase fuel economy with ever lower emissions, industry specialists and researchers presented key findings in new, combustion schemes and research.
Unmanned Aerial Systems and Ricardo will test a Nightwind 2 UAV powered by an all-new Ricardo engine designed specifically for JP-8 fuel. It promises significant gains in effective altitude, dwell time aloft, stealth operations, low thermal and acoustic profiles, and fuel efficiency.
The U.S. EPA has waived a limitation on selling fuel that is more than 10% ethanol for newer cars and light trucks. The E15 waiver applies only to model year 2007 and newer cars and light trucks. A decision on the use of E15 in model year 2001 to 2006 vehicles will be made after EPA receives the results of additional U.S.
While probably better known for its engineering solutions for ground vehicles, Ricardo announced in late May that it is developing a new purpose-built family of UAV engines for both civilian and military applications.
Britain’s Ricardo and QinetiQ pursue a cheaper and safer lithium-ion battery by targeting an iron-sulfide formulation with a high theoretical energy density.
Increased fuel efficiency—by as much as 10% or more—and reduced cost are two compelling reasons to consider any new technology. And these are two of the major benefits Ricardo claims for its new TorqStor advanced flywheel energy storage system.
A European Union-funded collaborative research project designed to convert exhaust waste heat into onboard electricity via is moving into the prototype stage, according to Ricardo. The company, a partner in the project (called PowerDriver), reported that recently completed simulation work on a potential automotive application of the thermo-electric generator technology (TGEN) indicates a possible output of 300 W and equivalent fuel savings over the NEDC drive cycle of 2.5%.
Stable pricing, low emissions, and fuel savings are prompting more engine manufacturers to develop natural gas engines.
Viewing 1 to 30 of 57


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