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In 2004 the European Parliament ratified the Euro III and IV standards limiting the pollutant emission of, among others, rail and marine diesel engines. In these sectors, it is particularly important to keep any fuel consumption penalty, when reducing emissions, to a strict minimum. Furthermore, exhaust gas after treatment is mostly avoided for cost reasons. Thus, manufacturers are looking to pretreatment of fuels, alternative fuels, and limiting engine-out emissions as ways to attain the required emission levels. This paper discusses the experimental work done on a 1324 kW, 1000 rpm six cylinder marine diesel engine equipped with mechanical unit injectors. The aim was to determine the influence of compression ratio and fuel injection parameters on engine-out emissions, with emphasis on NOx emissions. A range of fuel injection parameters were examined, varying the start of injection, pump plunger diameter, injection pressure, and injector nozzle geometry.

There is a growing consensus that there will not be a single alternative to fossil fuels, but rather different fuels, fuel feedstocks, engine types and operating strategies. For stationary diesel engines, straight vegetable oils are an interesting alternative to fossil diesel, because of their potential for lower life cycle greenhouse gas emissions. Using animal fats is also compelling, as it does not imply the cultivation of oil-bearing seeds and related emissions, not to mention the ‘food versus fuel’ debate. The aim of the present work is to correlate engine performance and durability with the properties (composition) of these alternative fuels, to provide a basis from which standards can be formulated for the properties of oils and fats to be used as engine fuel. Tests on different oils and fats are reported.

Medium speed diesel engines are well established today as a power source for heavy transport and stationary applications and it appears that they will remain so in the future. However, emission legislation becomes stricter, reducing the emission limits of various pollutants to extremely low values. Currently, many techniques that are well established for automotive diesel engines (common rail, after treatment, exhaust gas recirculation - EGR, …) are being tested on these large engines. Application of these techniques is far from straightforward given the different requirements and boundary conditions (fuel quality, durability, …). This paper reports on the development and experimental results of cooled, high pressure loop EGR operation on a 1326kW four stroke turbocharged medium speed diesel engine, with the primary goal of reducing the emission of oxides of nitrogen (NOx). Measurements were performed at various loads and for several EGR rates.

Powertrain efficiency is a critical factor in lowering fuel consumption and reducing the emission of greenhouse gases for an internal combustion engine. One method to increase the powertrain efficiency is to recover some of the wasted heat from the engine using a waste heat recovery system e.g. an organic Rankine cycle. Most waste heat recovery systems in use today for combustion engines use the waste heat from the exhaust gases due to the high temperatures and hence, high energy quality. However, the coolant represents a major source of waste heat in the engine that is mostly overlooked due to its lower temperature. This paper studies the potential of using elevated coolant temperatures in internal combustion engines to improve the viability of low temperature waste heat recovery.

Partially premixed combustion (PPC) is one of several advanced combustion concepts for the conventional diesel engine. PPC uses a separation between end of fuel injection and start of combustion, also called ignition dwell, to increase the mixing of fuel and oxidizer. This has been shown to be beneficial for simultaneously reducing harmful emissions and fuel consumption. The ignition dwell can be increased by means of exhaust gas recirculation or lower intake temperature. However, the most effective means is to use a fuel with high research octane number (RON). Methanol has a RON of 109 and a recent study found that methanol can be used effectively in PPC mode, with multiple injections, to yield high brake efficiency. However, the early start of injection (SOI) timings in this study were noted as a potential issue due to increased combustion sensitivity. Therefore, the present study attempts to quantify the changes in engine performance for different injection strategies.

The worldwide adoption of renewable energy mandates, together with the widespread utilization of biofuels has created a sharp increase in the production of biodiesel (fatty acid alkyl esters). As a consequence, the production of glycerol, the main by-product of the transesterification of fatty acids, has increased accordingly, which has led to an oversupply of that compound on the markets. Therefore, in order to increase the sustainability of the biodiesel industry, alternative uses for glycerol need to be explored and the production of fuel additives is a good example of the so-called glycerol valorization. The goal of this study is therefore to evaluate the suitability of a number of glycerol-derived compounds as diesel fuel additives. Moreover, this work concerns the assessment of low-concentration blends of those glycerol derivatives with diesel fuel, which are more likely to conform to the existing fuel standards and be used in unmodified engines.