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Knowledge of fuel mass injected in an individual cycle is important for engine performance and modelling. Currently direct measurements of fuel flow to individual cylinders of an engine are not possible on-engine or in real-time due to a lack of available appropriate measurement techniques. The objective of this work was to undertake real-time Coriolis fuel flow measurement using GDI injectors on a rig observing fuel mass flow rate within individual fuel injections. This paper evaluates the potential of this technology - combining Coriolis Flow Meters (CFMs) with Prism signal processing together known as Fast Next Generation Coriolis (Fast NGC), and serves as a basis for future transitions on-engine applications. A rig-based feasibility study has been undertaken injecting gasoline through a GDI injector at 150 bar in both single shot mode and at a simulated engine speeds of 1788 and 2978 rpm. The results show that these injections can, in principle, be observed.

For efficiency, the majority of modern diesel engines implement multiple injection strategies, increasing the frequency of transient injection phases and thus, end of injection (EOI) events. Recent advances in diagnostic techniques have identified several EOI phenomena pertinent to nozzle surface wetting as a precursor for deposit formation and a potential contributor towards pollutant emissions. To investigate the underlying processes, highspeed optical measurements at the microscopic scale were performed inside a motored diesel engine under low load/idling conditions. Visualisation of the injector nozzle surface and near nozzle region permitted an indepth analysis of the post-injection phenomena and the behaviour of fuel films on the nozzle surface when the engine is not fired. Inspection of the high-speed video data enabled an interpretation of the fluid dynamics leading to surface wetting, elucidating the mechanisms of deposition and spreading.

Rail pressures of modern diesel fuel injection systems have increased significantly over recent years, greatly improving atomisation of the main fuel injection event and air utilisation of the combustion process. Continued improvement in controlling the process of introducing fuel into the cylinder has led to focussing on fluid phenomena related to transient response. High-speed microscopy has been employed to visualise the detailed fluid dynamics around the near nozzle region of an automotive diesel fuel injector, during the opening, closing and post injection events. Complementary computational fluid dynamic (CFD) simulations have been undertaken to elucidate the interaction of the liquid and gas phases during these highly transient events, including an assessment of close-coupled injections.

Most major regional automotive markets have stringent legislative targets for vehicle greenhouse gas emissions or fuel economy enforced by fiscal penalties. Large improvements in vehicle efficiency on mandated test cycles have already taken place in some markets through the widespread adoption of technologies such as downsizing or dieselisation. There is now increased focus on approaches which give smaller, but significant incremental efficiency benefits, such as reducing parasitic losses due to engine friction. The reduction in tail pipe CO2 emissions through the reduction of engine friction using lubricants has been reported by many authors. However, opportunities also exist to reduce the lubricant viscosity during warm up by the thermal management of the lubricant mass.

Rising fuel prices and changes to CO2 and fuel economy legislation have prompted an interest in the electrification of vehicles since this can significantly improve vehicle tailpipe CO2 emissions over homologation test cycles. To this end plug-in hybrid electric vehicles (PHEVs) and range extended electric vehicles (REEVs) have been introduced to the market. The operation of the engines in these vehicles differs from conventional vehicles in several key ways. This study was conducted to better understand how the engine design and control strategy of these vehicles affects the temperature and operating regimes experienced by engine crankcase lubricants. A Toyota Prius Plug-in PHEV and GM Volt REEV were tested on a chassis dynamometer over several legislated and pseudo ‘real world’ drive cycles to determine the operating strategy and behaviour of the powertrain. The lubricant and coolant temperatures were monitored, together with other key control parameters.

Engine downsizing is a key approach employed by many vehicle manufacturers to help meet fleet average CO2 emissions targets. With gasoline engines in particular reducing engine swept volume while increasing specific output via technologies such as turbocharging, direct injection (DI) and variable valve timing can significantly reduce frictional and pumping losses in engine operating areas commonly encountered in legislative drive cycles. These engines have increased susceptibility to abnormal combustion phenomena such as knock due to the high brake mean effective pressures which they generate. This ultimately limits fuel efficiency benefits by demanding use of a lower geometric compression ratio and sub-optimal late combustion phasing at the higher specific loads experienced by these engines.

Most major regional automotive markets have stringent legislative targets for vehicle greenhouse gas emissions or fuel economy enforced by fiscal penalties. Large improvements in vehicle efficiency on mandated test cycles have already taken place in some markets through the widespread adoption of technologies such as downsizing or dieselization. There is now increased focus on approaches which give smaller but significant incremental efficiency benefits such as reducing parasitic losses due to engine friction. Fuel economy improvements which achieve this through the development of advanced engine lubricants are very attractive to vehicle manufacturers due to their favorable cost-benefit ratio. For an engine with components which operate predominantly in the hydrodynamic lubrication regime, the most significant lubricant parameter which can be changed to improve the tribological performance of the system is the lubricant viscosity.

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.

Five different fuels, including gasoline, commercial E85, pure methanol and two mixtures of gasoline, ethanol and methanol, (GEM), configured to a target stoichiometric air fuel ratio have been investigated in a fully-optically-accessed engine. The work investigated effects of injection duration, and performed spray imaging, thermodynamic analysis of the combustion and OH imaging, for two fixed engine conditions of 2.7 and 3.7 bar NMEP at 2000 rpm. The engine was operated with constant ignition timing for all fuels and both loads. One of the most important results from this study was the suitability of a single type of injector to handle all the fuels tested. There were differences observed in the spray morphology between the fuels, due to the different physical properties of the fuels. The energy utilisation measured in this study showed differences of up to 14% for the different GEM fuels whereas an earlier in-vehicle study had showed only 2 to 3%.

The use of methanol as spark-ignition engine fuel can help to increase energy security and offers the prospect of carbon neutral transport. Methanol's properties enable considerable improvements in engine performance, efficiency and CO2 emissions compared to gasoline operation. SAE paper 2012-01-1283 showed that both flex-fuel and dedicated methanol engines can benefit from an operating strategy employing exhaust gas recirculation (EGR) to control the load while leaving the throttle wide open (WOT). Compared to throttled stoichiometric operation, this reduces pumping work, cooling losses, dissociation and engine-out NOx. The current paper presents follow-up work to determine to what extent these advantages still stand over an entire drive cycle. The average vehicle efficiency, overall CO2 and NOx emissions from a flexible fuel vehicle completing a drive cycle on gasoline and methanol were evaluated.

The paper presents vehicle-based test work using tri-component, or ternary, blends of gasoline, ethanol and methanol for which the stoichiometric air-fuel ratio (AFR) was controlled to be 9.7:1. This is the same as that of conventional "E85" alcohol-based fuel. Such ternary blends are termed "GEM" after the first initial of the three components. The present work was a continuation of an earlier successful project which established that the blends were effectively invisible to a car using a virtual alcohol sensor. The vehicle used here employed the other major technology in flex-fuel vehicles to determine the proportion of alcohol fuel in the tank, a physical alcohol sensor. Another aspect of the present work included the desire to investigate ternary blend replacements for E85 having low ethanol concentrations. Evidence from the previous work suggested that under specific conditions, ethanol was required in some amount to act as a cosolvent for the gasoline and methanol in the blend.

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 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.

Omnivore is a single cylinder spark ignition based research engine conceived to maximize the operating range of auto-ignition on a variety of fossil and renewable fuels. In order to maximize auto-ignition operation, the two-stroke cycle was adopted with two independent mechanisms for control. The charge trapping valve system is incorporated as a means of varying the quantity of trapped residuals whilst a variable compression ratio mechanism is included to give independent control over the end of compression temperature. The inclusion of these two technologies allows the benefits of trapped residual gas to be maximised (to minimize NOx formation) whilst permitting variation of the onset of auto-ignition. 2000rpm and idle are the main focus of concern whilst also observing the influence of injector location. This paper describes the rational behind the engine concept and presents the results achieved at the time of writing using 98ulg and E85 fuels.

The paper critiques proposals for de-carbonizing transport and offers a potential solution which may be attained by the gradual evolution of the current fleet of predominantly low-cost vehicles via the development of carbon-neutral liquid fuels. The closed-carbon cycles which are possible using such fuels offer the prospect of maintaining current levels of mobility with affordable transport whilst neutralizing the threat posed by the high predicted growth of greenhouse gas emissions from this sector. Approaches to de-carbonizing transport include electrification and the adoption of molecular hydrogen as an energy carrier. These two solutions result in very expensive vehicles for personal transport which mostly lie idle for 95% of their life time and are purchased with high-cost capital.

The work reports results from tests employing different cooled EGR routes on a ‘Sabre’ direct-injection spark-ignition (DISI) research engine. As standard, this engine has been configured to provide good fuel consumption from a combination of mild downsizing, a combustion system with close-spaced injection and the adoption of a three-cylinder configuration in concert with an exhaust manifold integrated into the cylinder head. This has already been shown to offer a rated power specific fuel consumption of 272 g/kWh without cooled EGR. Three different EGR configurations are tested, with the best BSFC at nominal rated conditions being found to be 257-258 g/kWh at a cooled EGR rate of 6%. All of the EGR routing configurations tested in this work permit ready operation of the engine at Lambda 1 and MBT conditions, however, the results show little sensitivity in the combustion system to the actual routing employed.

Concerns over energy security and global warming are beginning to be a serious issue for society and are also starting to drive customer purchasing decisions across many areas. Against this background there is an increasing call for motor sport to improve its environmental image, despite the fact that the global energy consumption and CO2 emissions attributable to motor sport are a very low proportion of the total. The real issue for motor sport in the face of the wider societal concerns is that, if it is truly at the cutting edge of relevant automotive engineering, it should be configured and managed in such a way as to drive technology for the betterment of mankind. The status quo is, it is contended, increasingly seen to be blatantly energy-profligate in the eyes of many people and this issue must be resolved if motor sport is to demonstrate the wider benefits of the technology developed by the huge financial investments committed to competing at the highest level.

Many new technologies are being developed to improve the fuel consumption of gasoline engines, including the combination of direct fuel injection with turbocharging in a so-called ‘downsizing’ approach. In such spark ignition engines operating on the Otto cycle, downsizing targets a shift in the operating map such that the engine is dethrottled to a greater extent during normal operation, thus reducing pumping losses and improving fuel consumption. However, even with direct injection, the need for turbine protection fuelling at high load in turbocharged engines - which is important for customer usage on faster European highways such as German Autobahns - brings a fuel consumption penalty over a naturally-aspirated engine in this mode of operation.

The paper describes the design and development of ‘Sabre’, a 3-cylinder engine encompassing a combination of technologies to realise low CO2 in a practical automotive application while retaining driving pleasure (vehicle acceleration performance). This project is a partnership with Continental Automotive, in which Lotus Engineering is responsible for the base engine and combustion system. The decision process that led to a close-spaced direct injection combustion system that does not target high BMEP as the chief route to low fuel consumption is described. Instead of pursuing an approach in which specific power is maximized in order to reduce throttling losses at part load, mild downsizing coupled with throttling loss reduction and turbulence manipulation enabled by a switching valve train is employed.

The future exploitation of global energy resources is currently being hotly debated by politicians and by sections of the scientific community but there is little guidance available in the engineering literature as to the full gamut of options or their viability with respect to fuelling the world's vehicles. In the automotive industry extensive research is being undertaken on the use of alternative fuels in internal combustion engines and on the development of alternative powerplants but often the long-term strategy and sustainability of the energy sources to produce these fuels is not clearly enunciated. The requirement to reduce CO2 emissions in the face of accelerating global warming scenarios and the depletion of fossil-fuel resources has led to the widespread assumption that some form of ‘hydrogen economy’ will prevail; this view is seldom justified or challenged.