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Characterization of soot nanoparticle morphology can be used to develop understanding of nanoparticle interaction with engine lubricant oil and its additives. It can be used to help direct modelling of soot-induced thickening, and in a more general sense for combatting reductions in engine efficiency that occur with soot-laden oils. Traditional 2D transmission electron microscopy (TEM) characterization possesses several important shortcomings related to accuracy that have prompted development of an alternative 3D characterization technique utilizing electron tomography, known as 3D-TEM. This work details progress made towards facilitating semi-automated image acquisition and processing for location of structures of interest on the TEM grid. Samples were taken from a four cylinder 1.4 L gasoline turbocharged direct injection (GTDI) engine operated in typically extra-urban driving conditions for 20,284 km, with automatic cylinder deactivation enabled.

Environmental authorities such as EPA, VCA have enforced stringent emissions legislation governing air pollutants released into the atmosphere. Of particular interest is the challenge introduced by the limit on particulate number (PN) counting (#/km) and real driving emissions (RDE) testing; with new emissions legislation being shortly introduced for the gasoline direct injection (GDI) engines, gasoline particulate filters (GPF) are considered the most immediate solution. While engine calibration and testing over the Worldwide harmonized Light vehicles Test Cycle (WLTC) allow for the limits to be met, real driving emission and cold start constitute a real challenge. The present work focuses on an experimental durability study on road under real world driving conditions. Two sets of experiments were carried out. The first study analyzed a gasoline particulate filter (GPF) (2.4 liter, diameter 5.2” round) installed in the underfloor (UF) position and driven up to 200k km.

The causes of engine knock are well understood but it is important to be able to relate these causes to the effects of controllable engine parameters. This study attempts to quantify the effects of a portion of the available engine parameters on the knock behavior of a 60% downsized, DISI engine running at approximately 23 bar BMEP. The engines response to three levels of coolant flow rate, coolant temperature and exhaust back pressure were investigated independently. Within the tested ranges, very little change in the knock limited spark advance (KLSA) was observed. The effects of valve timing on scavenge flow and blow through (the flow of fresh air straight into the exhaust system during the valve overlap period) were investigated at two conditions; at fixed inlet/exhaust manifold pressures, and at fixed engine torque. For both conditions, a matrix of 8 intake/exhaust cam combinations was tested, resulting in a wide range of valve overlap conditions (from 37 to -53°CA).

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.

After years of study and improvement, turbochargers in passenger cars now generally have very high efficiency. This is advantageous, but on the other hand, due to their high efficiency, only a small portion of the exhaust energy is needed for compressing the intake air, which means further utilization of waste heat is restricted. From this point of view, a turbo-compounding arrangement has significant advantage over a turbocharger in converting exhaust energy as it is immune to the upper power demand limit of the compressor. However, with the power turbine being located in series with the main turbine, power losses are incurred due to the higher back pressure which increases the pumping losses. This paper evaluates the effectiveness that the turbo-compounding arrangement has on a 2.0 litres gasoline engine and seeks to draw a conclusion on whether the produced power is sufficient to offset the increased pumping work.

Market demand for high performance gasoline vehicles and increasingly strict government emissions regulations are driving the development of highly downsized, boosted direct injection engines. The in-cylinder temperatures and pressures of these emerging technologies tend to no longer adhere to the test conditions defining the RON and MON octane rating scales. This divergence between fuel knock rating methods and fuel performance in modern engines has previously led to the development of an engine and operating condition dependent scaling factor, K, which allows for extrapolation of RON and MON values. Downsized, boosted DISI engines have been generally shown to have negative K-values when knock limited, indicating a preference for fuels of higher sensitivity and challenging the relevance of a lower limit to the MON specification.

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).

The Divided Exhaust Period (DEP) concept is an approach which has been proved to significantly reduce the averaged back pressure of turbocharged engines whilst still improving its combustion phasing. The standard layout of the DEP system comprises of two separately-functioned exhaust valves with one valve feeding the blow-down pulse to the turbine whilst the other valve targeting the scavenging behaviour by bypassing the turbine. Via combining the characteristics of both turbocharged engines and naturally aspirated engines, this method can provide large BSFC improvement. The DEP concept has only been applied to single-stage turbocharged engines so far. However, it in its basic form is in no way restricted to a single-stage system. This paper, for the first time, will apply DEP concept to a regulated two-stage (R2S) downsized SI engine.

Engines equipped with pressure charging systems are more prone to knock partly due the increased intake temperature. Meanwhile, turbocharged engines when operating at high engine speeds and loads cannot fully utilize the exhaust energy as the wastegate is opened to prevent overboost. The turboexpansion concept thus is conceived to reduce the intake temperature by utilizing some otherwise unexploited exhaust energy. This concept can be applied to any turbocharged engines equipped with both a compressor and a turbine-like expander on the intake loop. The turbocharging system is designed to achieve maximum utilization of the exhaust energy, from which the intake charge is over-boosted. After the intercooler, the turbine-like expander expands the over-compressed intake charge to the required plenum pressure and reduces its temperature whilst recovering some energy through the connection to the crankshaft.

This paper describes the development and automated calibration of a compact analytically based model of the wall-wetting phenomenon of modern port fuel-injected (PFI) spark-ignition (SI) gasoline engines. The wall-wetting model, based on the physics of forced convection with phase change, is to be used in an automated model-based calibration program. The first stage of work was to develop a model of the wall-wetting phenomenon in Matlab. The model was then calibrated using experimental data collected from a 1.8-litre turbocharged I4 engine coupled to a dynamic 200kW AC dynamometer. The calibration was accomplished by adopting a two stage optimization approach. Firstly, a design of experiments (DoE) approach was used to establish the effect of the principal model parameters on a set of metrics that characterized the magnitude and duration of the measured lambda deviation during a transient.

The dilution of lubricating oil by fuel has adverse effects on engine wear, oil lubricity, air/fuel ratio control and feedgas emissions. Dilution is one of the factors limiting oil change intervals. The level and rate of accumulation depend on engine operating conditions and patterns of vehicle use. The work reported here develops and evaluates an empirical model to predict accumulation characteristics. This is aligned to requirements for predictions of dilution build-up in service. Predictions are shown to be in good agreement with data given in the literature. The model is used to investigate the influence of patterns of vehicle use on dilution.