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In-cylinder spray imaging by Mie scattering has been taken with frame rates up to 27,000 fps, along with high speed video photography of chemiluminescence and soot thermal radiation. Spectroscopic measurements have confirmed the presence of OH*, CH* and C2* emissions lines, and their magnitude relative compared to soot radiation. Filtering for CH* has been used with both the high speed video and a Photo-Multiplier Tube (PMT). The PMT signals have been found to correlate with the rate of heat release derived from in-cylinder pressure measurements. A high power photographic strobe has been used to illuminate the fuel spray. Images show that the fuel spray can strike the ground strap of the spark plug, break up, and a fuel cloud then drifts over and under the strap through the spark plug gap. Tests have conducted at two different spark plug orientations using a single spark strategy.

Particulate emissions from gasoline direct injection (GDI) engines continue to be a topic of substantial research interest. Forthcoming regulation both in the USA and the EU will further reduce their emission and drive innovation. Substantial research effort is spent undertaking experiments to understand, characterize, and research particle number (PN) emissions from engines and vehicles. Recent advances in computing power, data storage, and understanding of artificial intelligence algorithms now mean that these are becoming an important tool in engine research. In this work a random forest (RF) algorithm is used for the prediction of PN emissions from a highly boosted (up to 32 bar BMEP) GDI engine. Particle size, concentration, and the accumulation mode geometric standard deviation (GSD) are all predicted by the model. The results are analysed and an in depth study on parameter importance is carried out.

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.

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.

Investigations of low drag shapes for passenger vehicles were conducted in the 1930s but production cars of today have yet to approach the potential drag coefficients shown by that early research. Furthermore, the adoption of low drag styles has been resisted because of a perception of compromise to the exterior style and so recent aerodynamic developments have concentrated on changes to non-styled surfaces. However, environmental and ecological pressures are placing increasing demands on manufacturers to produce energy efficient vehicles and the contribution of aerodynamics in that equation is increasing, particularly with the adoption of technologies such as regenerative braking and measurements being made using more real-world use driving cycles. Relying on non-styled surfaces alone for drag reduction is unlikely to be sufficient to deliver the improvements required.

Models for the convective heat transfer from the combustion gases to the walls inside a spark ignition engine are an important keystone in the simulation tools which are being developed to aid engine optimization. The existing models have, however, been cited to be inaccurate for hydrogen, one of the alternative fuels currently investigated. One possible explanation for this inaccuracy is that the models do not adequately capture the effect of the gas properties. These have never been varied in a wide range because air and ‘classical’ fossil fuels have similar values, but they are significantly different in the case of hydrogen. As a first step towards a fuel independent heat transfer model, we have investigated the effect of the gas properties on the heat flux in a spark ignition engine.

Knowledge of fuel mass injected in an individual cycle is important for engine performance and modeling. At the moment, such measurements are not possible on engine or in real time. In this article, a new method using Coriolis flow meters (CFMs) and a new, patented, signal processing technique, known as the Prism, are introduced. CFMs are extensively used for flow measurement both in the automotive industry and further afield and, when coupled with the Prism, have the potential to make these challenging high-speed measurements. A rig-based feasibility study was conducted injecting very small quantities of diesel (3 mg) at pressures of up to 1000 bar at simulated engine speeds of up to 4000 rpm. The results show that these small quantities can in principle be measured. The results also reveal a previously unknown behavior of CFMs when measuring very low flow rates at high speed.

Spray guided Direct Injection Gasoline Engines are a key enabler to reducing CO2 emissions and improving the fuel economy of light duty vehicles. Particulate emissions from these engines have been shown to be lower than from first generation direct injection gasoline engines, but they may still be significantly higher than port fuel injected engines due to the reduced time available for mixture preparation and increased incidence of fuel impingement on the piston crown and combustion chamber surfaces. These factors are particularly severe in the period following a cold start. Both nuclei and accumulation mode particle size and number concentration were measured using a Cambustion differential mobility spectrometer. These data are reported for different coolant temperature intervals during the warm-up period. The bulk composition was determined using thermo-gravimetric analysis, and PM mass fractions are given for different volatility ranges and for elemental carbon.

With the ever increasing demand on automotive manufactures to reduce lead times, improve performance, add air conditioning, meet noise and pollution legislation the need to evaluate and improve cooling system performance at the design stage is becoming increasingly important. The cooling system is taken to encompass the full air path of grills, inlet plenum, cooling pack, under bonnet resistance and outlet to the free stream. This paper describes the main structure of a PC based computer program which is being developed to permit the cooling system performance to be optimized at the vehicle concept stage or prior to major updates to a model, which could be for example front end styling or a change of engine. Also discussed are details of how the air paths through the cooling pack, and the system resistances from the inlet grill to the engine compartment outlet are determined.

Particulate Emissions from Homogeneous Charge Compression Ignition (HCCI) combustion are routinely assumed to be negligible. It is shown here that this is not the case when HCCI combustion is implemented in a direct injection gasoline engine. The conditions needed to sustain HCCI operation were realized using the negative valve overlap method for trapping high levels of residual exhaust gases in the cylinder. Measurements of emitted particle number concentration and electrical mobility diameter were made with a Cambustion DMS500 over the HCCI operating range possible with this hardware. Emissions of oxides of nitrogen, carbon monoxide and unburned hydrocarbons were also measured. These data are presented and compared with similar measurements made under conventional spark ignition (SI) operation in the same engine. Under both SI and HCCI operation, a significant accumulation mode was detected with particle equivalent diameters between 80 and 100 nm.

The blending of oxygenated compounds with gasoline is projected to increase because oxygenate fuels can be produced renewably, and because their high octane rating allows them to be used in substitution of the aromatic fraction in gasoline. Blending oxygenates with gasoline changes the fuels' properties and can have a profound affect on the distillation curve, both of which are known to affect engine-out emissions. In this work, the effect of blending methanol and ethanol with gasoline on unburned hydrocarbon and particulate emissions is experimentally determined in a spray guided direct injection engine. Particulate number concentration and size distribution were measured using a Cambustion DMS500. These data are presented for different air fuel ratios, loads, ignition timings and injection timings. In addition, the ASTM D86 distillation curve was modeled using the binary activity coefficients method for the fuel blends used in the experiments.

The topic of energy management in Hybrid Electric Vehicles (HEVs) has received a great deal of recent attention. Various methods have been proposed to develop algorithms which manage energy flows within HEVs so that to optimally exploit energy storage capability of the battery and reduce fuel consumption while maintaining battery State of Charge. In addition, to the rule-based approaches, systematic optimal control methods based on deterministic and stochastic dynamic programming have been explored for HEV energy management optimization. In this paper, another novel framework based on the application of game theory is proposed, in which the HEV operation is viewed as a non-cooperative game between the driver and the powertrain.

Planar Laser-Induced Fluorescence has been widely accepted and applied to measurements of fuel concentration distributions in IC engines. The need for such measurements has increased with the introduction of Direct Injection (DI) gasoline engines, where it is critical to understand the influence of mixture inhomogeneity on ignition and subsequent combustion, and in particular the implications for cyclic variability. The apparent simplicity of PLIF has led to misunderstanding of the technique when applied to quantitative measurements of fuel distributions. This paper presents a series of engineering methods for optimizing, calibrating and referencing, which together demonstrate a quantitative measure of fuel concentration with an absolute accuracy of 10%. PLIF is widely used with single component fuels as carriers for the fluorescent tracers.

Increasing biodiesel content in mineral diesel is being promoted considerably for road transportation in Europe. With positive benefits in terms of net CO2 emissions, biofuels with compatible properties to those of conventional diesel are increasingly being used in combustion engines. In comparison to standard diesel fuel, the near zero sulphur content and low levels of aromatic compounds in biodiesel fuel can have a profound effect not only on combustion characteristics but on engine-out emissions as well. This paper presents analysis of particulate matter (PM) emissions from a turbo-charged, common rail direct injection (DI) V6 Jaguar engine operating with an RME (rapeseed methyl ester) biodiesel blended with ultra low sulphur diesel (ULSD) fuel (B30 - 30% of RME by volume). Three different engine load and speed conditions were selected for the test and no modifications were made to the engine hardware or engine management system (EMS) calibration.

Particulate Matter (PM) legislation for gasoline engines and the introduction of gasoline/ethanol blends, make it important to know the effect of fuel composition on PM emissions. Tests have been conducted with fuels of known composition in both a single-cylinder engine and V8 engine with a three-way catalyst. The V8 engine used an unleaded gasoline (PURA) with known composition and distillation characteristics as a base fuel and with 10% by volume ethanol. The single-cylinder engine used a 65% iso-octane - 35% toluene mixture as its base fuel. The engines had essentially the same combustion system, with a centrally mounted 6-hole spray-guided direct injection system. Particle size distributions were recorded and these have also been converted to mass distributions. Filter samples were taken for thermo-gravimetric analysis (TGA) to give composition information. Both engines were operated at 1500 rpm under part load.

Modeling of SCR in diesel exhaust systems with injection of urea spray is complex and challenging but many models use only the conversion observed at the brick exit as a test of the model. In this study, the case modeled is simplified by injecting ammonia gas in nitrogen in place of urea, but the spatial conversion profiles along the SCR brick length at steady state are investigated. This is a more rigorous way of assessing the ability of the model to simulate observations made on a test exhaust system. The data have been collected by repeated engine tests on eight different brick lengths, all which were shorter than a standard-sized SCR. The tests have been carried out for supplied NH₃ /NOx ratios of a 1.5, excess ammonia, a 1.0, balanced ammonia, and a 0.5, deficient ammonia. Levels of NO, NO₂ and NH₃ have been measured both upstream and downstream of the SCR using a gas analyzer fitted with ammonia scrubbers to give reliable NOx measurements.

This paper investigates the flow maldistribution across the monolith of an axisymmetric catalyst assembly fitted to a pulsating flow test rig. Approximately sinusoidal inlet pulse shapes with relatively low peak/mean ratio were applied to the assembly with different amplitudes and frequencies. The inlet and outlet velocities were measured using Hot Wire Anemometry. Experimental results were compared with a previous study, which used inlet pulse shapes with relatively high peak/mean ratios. It is shown that (i) the flow is more maldistributed with increase in mass flow rate, (ii) the flow is in general more uniformly distributed with increase in pulsation frequency, and (iii) the degree of flow maldistribution is largely influenced by the different inlet velocity pulse shapes. Transient CFD simulations were also performed for the inlet pulse shapes used in both studies and simulations were compared with the experimental data.

This paper describes the coupling of a 1D engine simulation code (Ricardo WAVE) to a 3D CFD code (STAR-CD) to study the flow behaviour inside a Close-Coupled Catalytic converter (CCC). A SI engine was modelled in WAVE and the CCC modelled in STAR-CD. The predictions of the stand-alone WAVE model were validated against engine bed tests before the coupled 1D/3D simulations were performed at 3000 RPM WOT for both motored and firing conditions. The predicted exhaust velocities downstream of the catalyst monolith in the coupled simulations matched fairly well with Laser Doppler Anemometry (LDA) measurements.

The analysis of thermal fields in the underhood region is complicated by the complex geometry and the influence of a multitude of different heat sources. This complexity means that running full CFD analyses to predict the thermal field in this region is both computationally expensive and time consuming. A method of predicting the thermal field using linear superposition has been developed in order to analyse the underhood region of a simplified Formula One race car, though the technique is applicable to all vehicles. The use of linear superposition allows accurate predictions of the thermal field within a complex geometry for varying boundary conditions with negligible computational costs once the initial characterisation CFD has been run. A quarter scale, rear end model of a Formula One race car with a simplified internal assembly is considered for analysis, though the technique can also be applied to commercial and industrial vehicles.

PICASSOS was a UK government funded programme to improve the ability of automotive supply chains to develop complex software-intensive systems with high safety assurance and at an acceptable cost. This was executed by a consortium of three universities and five companies including an automotive OEM and suppliers. Three major elements of the PICASSOS project were: use of automated model based verification technology utilising formal methods; application of this technology in the context of ISO 26262; and evaluation to measure the impact of this approach to inform key management decisions on the costs, benefits and risks of applying this technology on live projects. The project spanned system level design and software development. This was achieved by using a unified model based process incorporating SysML at the system level and using Simulink and Stateflow auto-coded into C at the software level.