Entity

Time filter

Source Type

Lotus, United Kingdom

Turner J.W.G.,Powertrain Research | Pearson R.J.,Powertrain Research | Bell A.,Sasol Limited | de Goede S.,Sasol Limited | Woolard C.,University of Cape Town
SAE International Journal of Fuels and Lubricants | Year: 2012

Iso-stoichiometric ternary blends - in which three-component blends of gasoline, ethanol and methanol are configured to the same stoichiometric air-fuel ratio as an equivalent binary ethanol-gasoline blend - can function as invisible 'drop-in' fuels suitable for the existing E85/gasoline flex-fuel vehicle fleet. This has been demonstrated for the two principal means of detecting alcohol content in such vehicles, which are considered to be a virtual, or software-based, sensor, and a physical sensor in the fuel line. Furthermore when using such fuels the tailpipe CO2 emissions are essentially identical to those found when the vehicle is operated on E85. Because of the fact that methanol can be made from a wider range of feed stocks than ethanol and at a cheaper price, these blends then provide opportunities to improve energy security, to reduce greenhouse gas emissions and to produce a fuel blend which could potentially be cheaper on a cost-per-unit-energy basis than gasoline or diesel. The present work extends the validation process for these blends by presenting exhaust emissions measured from a vehicle fitted with a physical alcohol sensor and operated on several ternary blends equivalent to E85. These results show that existing emissions control technology can easily manage exhaust gas after treatment when a vehicle is operated on such lends. This is an important finding with regard to their manufacturer and regulatory acceptance. Also, the impact of the methanol-containing nature of ternary blends was investigated. In order to do this, target ternary blends of gasoline, ethanol and methanol were prepared with the low oxygen content Coordinated European Council (CEC) emissions reference fuel CEC RF-02-03 and results of physicochemical analyses are presented. These include water tolerance, blend stability, thermal and oxidative stability, volatility and density. Nitrile rubber, Viton and silicone rubber seal swell properties are presented and discussed. In order to investigate octane effects, iso-stoichiometric blends equivalent to E15 were prepared and analyzed, and utilizing molar octane blending modelling the expected E85-equivalent blend octane indices can be predicted. As a result of this work observations are made on air-quality and materials compatibility impacts, and the attractiveness of the approach from a governmental and customer view point. © 2012 Lotus Cars Limited. Source


Patel R.,University College London | Ladommatos N.,University College London | Stansfield P.A.,Loughborough University | Wigley G.,Loughborough University | And 5 more authors.
International Journal of Engine Research | Year: 2010

Two direct injection spark ignition (DISI) engines with identical combustion chamber geometries and fuel injection systems were used to investigate fuel economy, exhaust emissions, the in-cylinder flow field, the fuel spray behaviour and combustion characteristics with early inlet valve closure (EIVC) strategies aimed at reducing parasitic induction work owing to throttling. One engine had extensive optical access through a transparent piston crown and transparent cylinder liner, while the other all-metal engine allowed continuous running. Engine running focused at low and intermediate engine loads (∼3 and ∼6 bar indicated mean effective pressure) and two engine speeds (2000 and 3500 r/min). The results show that the indicated specific fuel consumption (ISFC) could be reduced by almost 6 per cent without significant deterioration in gaseous exhaust pollutant emissions. The results also show that the in-cylinder bulk flow and turbulence and the thermodynamic conditions during combustion are affected significantly by EIVC operation. © Authors 2010. Source


Turner J.,Powertrain Research | Pearson R.,Powertrain Research | Purvis R.,Powertrain Research | Dekker E.,Biomcn Inc. | And 2 more authors.
SAE Technical Papers | Year: 2011

The paper presents the concept of ternary blends of gasoline, ethanol and methanol in which the stoichiometric air-fuel ratio (AFR) is controlled to be 9.7:1, the same as that of conventional 'E85' alcohol-based fuel. This makes them iso-stoichiometric. Such blends are termed 'GEM' after the first initial of the three components. Calculated data is presented showing how the volumetric energy density relationship between the three components in these blends changes as the stoichiometric AFR is held constant but ethanol content is varied. From this data it is contended that such GEM blends can be 'drop-in' alternatives to E85, because when an engine is operated on any of these blends the pulse widths of the fuel injectors would not change significantly, and so there will be no impact on the on-board diagnostics from the use of such blends in existing E85/gasoline flex-fuel vehicles. The resulting ability of such blends to extend the reach of a fixed amount of ethanol in the fuel pool is then demonstrated, together with the mechanism by which the addition of the methanol displaces additional gasoline. If the methanol used is of a renewable and energy-secure nature then, for a fixed volume of ethanol in the fuel pool, an increased level of renewability and energy security is achieved. This overall situation is made possible by the fact that there are more E85/flex-fuel vehicles in existence than can currently be serviced by the E85 fuel supply chain. Example price calculations are conducted to show the points of potential price competitiveness. Preliminary tests with such GEM blends in a production-specification E85/gasoline vehicle were conducted to show the validity of the approach, and the results are reported together with fuel characteristics such as RON, MON and sensitivity. Road mileage is also reported using one of the fuel blends. Together these findings show the attractiveness of the concept and that there is therefore a possibility to significantly extend the use of renewable alcohol fuel in the market due to the miscibility of gasoline, ethanol and methanol. This is primarily because, when they are blended to a target stoichiometric AFR, any of the blends possible share essentially the same volumetric energy content, RON, MON, sensitivity and latent heat (to within 4%). In turn, this makes taxation and pricing of such fuels simple and straightforward, further removing roadblocks to introduction. Copyright © 2011 Lotus Cars Limited. Source


Turner J.,Powertrain Research | Blake D.,Powertrain Research | Moore J.,Powertrain Research | Burke P.,Powertrain Research | And 7 more authors.
SAE International Journal of Engines | Year: 2010

The paper discusses the concept, specification and performance of a new, dedicated range extender engine for plug-in series hybrid vehicles conceived and designed by Lotus Engineering. This has been undertaken as part of a consortium project called Limo Green, part-funded by the UK government. The Lotus Range Extender engine has been conceived from the outset specifically as an engine for a plug-in series hybrid vehicle, therefore being free of some of the constraints placed on engines which have to mate to conventional, stepped mechanical transmissions. The paper starts by defining the philosophical difference between an engine for range extension and an engine for a full series hybrid vehicle, a distinction which is important with regard to how much power each type must produce. As part of this, the advantages of the sparkignition engine over the diesel are outlined. The rationale leading to the adoption of an in-line 3-cylinder configuration and specification is then discussed, followed by a description of the principal design characteristics of the engine; it also points out any significant differences from what might be expected were a 'conventional' engine to be designed. The use of 'monoblock' construction which integrates the cylinder block with the cylinder head and also with a watercooled exhaust manifold is described. An indication of the likely parts reduction possible with this approach is made, together with a brief discussion of the pros and cons of the approach and which other engine types this architecture might suit. Engine performance on 95 RON unleaded gasoline is detailed, together with observations on why the engine has been additionally protected to operate on ethanol and methanol. The paper also includes a brief discussion of other engine concepts which might suit the purpose of range extension, but which (compared to the more conventional reciprocating spark-ignition engine embodied by this approach) will necessarily require greater development even if they may offer the potential for further improved efficiency, package volume and/or NVH characteristics. © 2010 Lotus Cars Ltd. Source

Discover hidden collaborations