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The in-cylinder direct injection of fuels can be a further step towards cleaner and more efficient internal combustion engines. However, the injector design and its characterization, both experimental and from numerical simulation require accurate diagnostics and efficient models. This work aims to simulate the complex behavior of the gaseous and liquid jets through an outwardly opening injector characterized by optical diagnostics using a one-dimensional model without using three dimensional models. The behavior of the jet from an outwardly opening injector changes according to the type of fuel. In the case of the gas, the experimental investigations put in evidence three main jet regions: 1) near-field region where the jet shows a complex gas-dynamic structure; 2) transition region characterized by intense mixing; 3) far-field region characterized by a fully developed subsonic turbulent jet.

Abstract Regulations limiting GreenHouse Gases (GHG) from Heavy-Duty (HD) commercial vehicles in the United States (US) and European Union will phase in between the 2024 and 2030 model years. These mandates require efficiency improvements at both the engine and vehicle levels, with the most stringent reductions required in the heaviest vehicles used for long-haul applications. At the same time, a 90% reduction in oxides of nitrogen (NOx) will be required as part of new regulations from the California Air Resources Board. Any technologies applied to improve engine efficiency must therefore not come at the expense of increased NOx emissions. Research into advanced engine architectures and components has identified improved turbomachine efficiency as one of the largest potential contributors to engine efficiency improvement. However this comes at the cost of a reduced capability to drive high-pressure Exhaust Gas Recirculation (EGR).

In the truck industry there is a continuous demand to increase the efficiency and to decrease the emissions. To acknowledge both these issues a waste heat recovery system (WHR) is combined with a partially premixed combustion (PPC) engine to deliver an efficient engine system. Over the past decades numerous attempts to increase the thermal efficiency of the diesel engine has been made. One such attempt is the PPC concept that has demonstrated potential for substantially increased thermal efficiency combined with much reduced emission levels. So far most work on increasing engine efficiency has been focused on improving the thermal efficiency of the engine while WHR, which has an excellent potential for another 1-5 % fuel consumption reduction, has not been researched that much yet. In this paper a WHR system using a Rankine cycle has been developed in a modeling environment using IPSEpro.

A correlation study of vehicle exhaust emissions measurements was conducted by the West Virginia University (WVU) Transportable Heavy-Duty Vehicle Emissions Testing Laboratory and the Los Angeles County Metropolitan Transportation Authority (MTA) Emissions Testing Facility. A diesel fueled transit bus was tested by both chassis dynamometer emissions testing laboratories. Exhaust emissions were sampled from the tested vehicle during the operation of the Federal Transit Administration (FTA) Central Business District (CBD) testing cycle. Data of gaseous and particulate matter emissions was obtained at each testing laboratory. The emissions results were compared to evaluate the effects of different equipment, test procedures, and drivers on the measurements of exhaust emissions of heavy-duty vehicles operated on a chassis dynamometer.

The authors used a mass spectrometer to determine an SOF reduction mechanism of a diesel oxidation catalyst. The results indicate that SOF reduction lies in the catalytic conversion of high molecular organic matter to low molecular organic matter. And unregulated emissions are also reduced through this conversion. It is also found that the SOF reduction performance is highly dependent up on the condition of the wash coat. There is some limitation to improving diesel oxidation catalyst performance because of the sulfur content found in diesel fuel. Finally, the authors have determined what we think are the specifications of the presently best catalytic converter.

We propose a novel dual-fuel combustion model for simulating heavy-duty engines with the G-Equation. Dual-Fuel combustion strategies in such engines features direct injection of a high-reactivity fuel into a lean, premixed chamber which has a high resistance to autoignition. Distinct combustion modes are present: the DI fuel auto-ignites following chemical ignition delay after spray vaporization and mixing; a reactive front is formed on its surroundings; it develops into a well-structured turbulent flame, which propagates within the premixed charge. Either direct chemistry or the flame-propagation approach (G- Equation), taken alone, do not produce accurate results. The proposed Dual-Fuel model decides what regions of the combustion chamber should be simulated with either approach, according to the local flame state; and acts as a “kernel” model for the G- Equation model. Direct chemistry is run in the regions where a premixed front is not present.

This paper describes recent progress in our program to develop an emissions technology allowing diesel engines to meet the upcoming 2007/2010 regulations for NOx. At the heart of this technology is the ArvinMeritor Diesel Fuel Reformer that reforms the fuel, on-demand, on-board a vehicle. The fuel reformer uses plasma to partially oxidize a mixture of diesel fuel and air creating a highly reducing mixture of Hydrogen and Carbon monoxide. In a previous publication, we have demonstrated that using a reformate rich in H2 and CO to regenerate a NOx trap is highly advantageous compared to vaporized diesel fuel used conventionally. In this paper we present results and a strategy for performing desulfation of the traps using the fuel reformer. In contrast to vaporized diesel, which requires very high temperatures that fall outside the normal exhaust operating temperatures for diesel engines, desulfation was achieved at temperatures lower by more than 100 °C using the Plasma Fuel Reformer.

A 13 L HD diesel engine was converted to run as a flame propagation engine using the HEDGE™ Dual-Fuel concept. This concept consists of pre-mixed gasoline ignited by a small amount of diesel fuel - i.e., a diesel micropilot. Due to the large bore size and relatively high compression ratio for a pre-mixed combustion engine, high levels of cooled EGR were used to suppress knock and reduce the engine-out emissions of the oxides of nitrogen and particulates. Previous work had indicated that the boosting of high dilution engines challenges most modern turbocharging systems, so phase I of the project consisted of extensive simulation efforts to identify an EGR configuration that would allow for high levels of EGR flow along the lug curve while minimizing pumping losses and combustion instabilities from excessive backpressure. A potential solution that provided adequate BTE potential was consisted of dual loop EGR systems to simultaneously flow high pressure and low pressure loop EGR.

Combustion control strategy for high efficiency and low emissions in a heavy duty (H D) diesel engine was investigated experimentally in a single cylinder test engine with a common rail fuel system, EGR (Exhaust Gas Recirculation) system, boost system and retarded intake valve closing timing actuator. For the operation loads of IMEPg (Gross Indicated Mean Effective Pressure) less than 1.1 MPa the low temperature combustion (LTC) with high rate of EGR was applied. The fuel injection modes of either single injection or multi-pulse injections, boost pressure and retarded intake valve closing timing (RIVCT) were also coupled with the engine operation condition loads for high efficiency and low emissions. A higher boost pressure played an important role in improving fuel efficiency and obtaining ultra-low soot and NOx emissions.

There is potential to reduce GHG emissions in the HDV sector through different powertrain options (electric batteries, fuel cell batteries, and combustion engines), and different fuel or energy choices (hydrogen, biofuels, natural gas). The climate impacts of these technologies and fuels vary over the lifetime of the vehicle model. From extracting and processing raw materials to operation and maintenance, some powertrain options are more energy intensive to build than their counterparts, and some fuel sources can produce higher emissions during their production or use. The study uses a life-cycle assessment to analyze the options to allow policymakers and manufacturing companies to compare which powertrain and fuel options provide the largest GHG emissions reductions.

Biofuel can enable a sustainable transport solution and lower greenhouse gas emissions compared to standard fuels. This study focuses on biodiesel, implemented in the easiest way as drop in fuel. When mixing biodiesel into diesel one can run into problems with solubility causing contaminants precipitating out as insolubilities. These insolubilities, also called soft particles, can cause problems such as internal injector deposits and nozzle fouling. One way to overcome the problem of soft particles is by filtration. It is thus of great interest to be able to quantify fuel filters’ ability to intercept soft particles. The aim of this study is to test different fuel filters for heavy-duty engines and their ability to filter out synthetic soft particles. A custom-built fuel filter rig is presented, together with some of its general design requirements. For evaluation of the efficiency of the filters, fuel samples were taken before and after the filters.

As a result of the Kyoto Protocol [1], the European Union's legislation demands higher saving rates for the total energy consumption of technical equipment. Heavy Equipment, such as construction- and agricultural machines, contributes over 80% of the total off-road diesel fuel consumption in Germany per annum. It is therefore necessary to provide helpful solutions in order to reach this ambitious aim. The German Federal Ministry of Education and Research cooperates with machine manufacturers, component suppliers and research institutes in the area of heavy equipment. Under the project name TEAM [2] a three year project has been started, which is focused on the development and integration of new propulsion and steering systems for heavy equipment. One task within the project is finding an appropriate way of evaluating the energy efficiency of the enhanced machines, after the powertrain modifications have been applied to it.

An organic Rankine Bottoming cycle added to Diesel engines used for long-haul trucks has the potential of improving their peak fuel economy by up to 15% over a typical duty cycle. General Electric has developed a multi-vane rotary expander which has a measured isentropic brake efficiency of 80+% over a wide range of speed and power levels with organic working fluids. High cycle efficiency for design and off-design conditions is achieved with the multi-vane expander. The potential advantages of the multi-vane expander for the Diesel engine bottoming cycle include the elimination of a high speed gear box and the potential for over 80% isentropic engine efficiency. The multi-vane expander is a ruggedly built component running at Diesel engine speed. This paper describes the design and evaluation of a nominal 40 HP multi-vane expander for this application.

The performance of five positive k-factor injector tips has been assessed in this work by analyzing a comprehensive set of injected mass, momentum, and spray measurements. Using high speed shadowgraphs of the injected diesel plumes, the sensitivities of measured vapor penetration and dispersion to injection pressure (100-250MPa) and ambient density (20-52 kg/m3) have been compared with the Naber-Siebers empirical spray model to gain understanding of second order effects of orifice diameter. Varying in size from 137 to 353μm, the orifice diameters and corresponding injector tips are appropriate for a relatively wide range of engine cylinder sizes (from 0.5 to 5L). In this regime, decreasing the orifice exit diameter was found to reduce spray penetration sensitivity to differential injection pressure. The cone angle and k-factored orifice exit diameter were found to be uncorrelated.

Today’s growing commercial vehicle population creates a demand for fossil fuel surplus requirement and develops highly polluted urban cities in the world. Hence addressing both factors is very much essential. Battery electric vehicles are with limited vehicle range and higher charging time. So it is not suitable for the long-haul application. In further the hydrogen fuel cell-based electric vehicles are the future of the commercial electric vehicle to achieve long-range, zero-emission and alternate for reducing fossil fuels requirement. The hydrogen fuel cell electric vehicle range, it means the total distance covered by the vehicle in a single filling of hydrogen into the onboard cylinders. And here the prediction of the vehicle range is essential based on optimal parameters; vehicle acceleration, speed, trip time etc. before the start of the trip.

Abstract Due to the incoming phase out of fossil fuels from the market in order to reduce the carbon footprint of the automotive sector, hydrogen-fueled engines are candidate mid-term solution. Thanks to its properties, hydrogen promotes flames that poorly suffer from the quenching effects toward the engine walls. Thus, emphasis must be posed on the heat-up of the oil layer that wets the cylinder liner in hydrogen-fueled engines. It is known that motor oils are complex mixtures of a number of mainly heavy hydrocarbons (HCs); however, their composition is not known a priori. Simulation tools that can support the early development steps of those engines must be provided with oil composition and properties at operation-like conditions. The authors propose a statistical inference-based optimization approach for identifying oil surrogate multicomponent mixtures. The algorithm is implemented in Python and relies on the Bayesian optimization technique.

Abstract In view of the combustion efficiency and emission performance, various new clean combustion modes put forward higher requirements for the performance of the fuel injection system, and the cavitating two-phase flow characteristics in the injector nozzle have a significant impact on the spray atomization and combustion performance. This article comprehensively discusses and summarizes the factors that affect cavitation and the effectiveness of cavitation, and presents the research status and existent problems under each factor. Among them, viscosity factors are a hot research topic that researchers are passionate about, and physical properties factors still have the value of further in-depth research. However, the importance of material surface factors ranks last since the nozzle material was determined. Establishing a more comprehensive cavitation–atomization model considering various factors is the focus of research on cavitation phenomena.

Exhaust gas recirculation (EGR) is a suitable strategy to optimize heavy duty natural gas (NG) engines. EGR could be utilized to have high specific power, with low thermal stress, but also to increase engine efficiency. NG fuelling permits a large flexibility in EGR system design, due to very clean engine exhaust. In this paper, three types of EGR routes have been studied. The best set up, which can introduce the highest EGR quantities, to provide the best reduction of the thermal load at rated power, was found to be a cooled low pressure EGR route. However high low pressure route (HLPR) could give the possibility to increase engine efficiency by modulating the power output in the widest un-throttled range operation.

Correlations of simply calculated fuel spray parameters with measured ISFC and smoke trends in a swirling direct injection diesel engine are described. These are based on a large number of results from experiments carried out on a 120.7 mm bore engine in which the induction swirl could be varied. The correlations indicate that (i) the fuel spray tip velocity at impingement on the chamber wall and (ii) the ‘crosswind’ over the spray at impingement have important influences. Based on these it is deduced that engine speed-related turbulence is a rate-controlling factor in DI diesel combustion.

New heavy-duty vehicles are simulated with the Vehicle Energy Consumption Calculation Tool (VECTO) to certify their fuel consumption and CO2 emissions in the European Union. The vehicle manufacturer runs the simulation tool and requires the vehicle components' characteristics to simulate the vehicle over standardized mission profiles. The detailed component characteristics required to run the tool are not always publicly available. In this work, a simplified model was developed to predict the fuel consumption and CO2 emissions of heavy buses over the VECTO mission profiles. It requires only the basic vehicle properties as input, such as the air drag, tire rolling resistance, mass, drivetrain efficiency and auxiliary power use. The model was derived from detailed VECTO simulations of numerous variants of a diesel high floor bus, a diesel low floor bus and a CNG low floor bus.