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Tighter emission limits are discussed and established around the world to improve quality of the air we breathe. In order to control global warming, authorities ask for lower CO2 emissions from combustion engines. Lots of efforts are done to reduce engine out emissions and/or reduce remaining by suitable after treatment systems. Watlow, among others, a manufacturer of high accurate, active temperature sensor ExactSense™, wanted to understand if temperature sensor accuracy can have an influence on fuel consumption (FC). For this purpose a numerical approach was chosen where several non-road driving cycles (NRTCs) were simulated with the data base of a typical Stage IV heavy duty diesel engine. The engine is equipped with an exhaust gas after treatment system consisting of a DOC, CDPF and an SCR. In this work scope, the investigations shall be restricted to the FC benefits obtained in the active and passive DPF regeneration.

Measures for reducing engine friction within the powertrain are assessed in this paper. The included measures work in combination with several new technologies such as new combustion technologies, downsizing and alternative fuels. The friction reduction measures are discussed for a typical gasoline vehicle. If powertrain friction could be eliminated completely, a reduction of 15% in CO2 emissions could be achieved. In order to comply with more demanding CO2 legislations, new technologies have to be considered to meet these targets. The additional cost for friction reduction measures are often lower than those of other new technologies. Therefore, these measures are worth following up in detail.

Fuel consumption and NOx emissions of gasoline engines at part load can be significantly reduced by Controlled Auto-Ignition combustion concepts. However, the range of Gasoline Controlled Auto-Ignition (GCAI) operation is still limited by lacking combustion stability at low load and by high pressure-rise rates toward higher loads. Previous investigations indicate that the auto-ignition process is particularly determined by the thermodynamic state of the charge and by stratification effects of residual gas, temperature, and air-fuel ratio. However, little experimental data exist on the direct influence of mixture stratification on local ignition and heat-release rate (HRR) in direct-injection (DI) GCAI engines, because it is challenging to measure all the relevant charge and combustion parameters quasi-simultaneously with sufficient spatial/temporal resolution and precision.

Model-based control strategies along with an adapted calibration process become more important in the overall vehicle development process. The main drivers for this development trend are increasing numbers of vehicle variants and more complex engine hardware, which is required to fulfill the more and more stringent emission legislation and fuel consumption norms. Upcoming fundamental changes in the homologation process with EU 6c, covering an extended range of different operational and ambient conditions, are suspected to intensify this trend. One main reason for the increased calibration effort is the use of various complex aftertreatment technologies amongst different vehicle applications, requiring numerous combustion modes. The different combustion modes range from heating strategies for active Diesel Particulate Filter (DPF) regeneration or early SCR light-off and rich combustion modes to purge the NOx storage catalyst (NSC) up to partially premixed combustion modes.

The aim of this research collaboration focuses on the realization of a novel Diesel combustion control strategy, known as Digital Combustion Rate Shaping (DiCoRS) for transient engine operation. Therefore, this paper presents an initial, 3D-CFD simulation based evaluation of a physical model-based feedforward controller, considered as a fundamental tool to apply real-time capable combustion rate shaping to a future engine test campaign. DiCoRS is a promising concept to improve noise, soot and HC/CO emissions in parallel, without generating drawbacks in NOx emission and combustion efficiency. Instead of controlling distinct combustion characteristics, DiCoRS aims at controlling the full combustion process and therefore represents the highest possible degree of freedom for combustion control. The manipulated variable is the full injection profile, generally consisting of multiple injection events.

This study investigated dual-fuel operation with a light duty Diesel engine over a wide engine load range. Ethanol was hereby injected into the intake duct, while Diesel was injected directly into the cylinder. At low loads, high ethanol shares are critical in terms of combustion stability and emissions of unburnt hydrocarbons. As the load increases, the rates of heat release become problematic with regard to noise and mechanical stress. At higher loads, an advanced injection of Diesel was found to be beneficial in terms of combustion noise and emissions. For all tests, engine-out NOx emissions were kept within the EU-6.1 limit.

Crankshaft is a dynamic component that copes with elevated alternating stresses. In order to ensure the service reliability, fillet rolling process is being applied. The state of the art empirical assumptions to consider the effect of fillet rolling process on crankshaft fatigue are conservative. This leads to an over-engineering of the crankshaft. However, calculation of the compressive residual stresses due to surface treatment is a demanding task. The quality of the durability analysis can only be increased by an accurate consideration of the fillet rolling effect. Therefore, Hegenscheidt-MFD, FEV Motorentechnik and Institute for Combustion Engines (VKA) cooperated to enlighten the phenomenon of the fillet rolling process. Process calculations are applied and validated by the measurements and tests. The calculated residual stresses are then superposed with the dynamic loads calculated by FEV Virtual Engine.

During a thermal regeneration of a Diesel particulate filter (DPF) the temperature inside the DPF may raise above critical thresholds in an uncontrolled way (thermal shock). Especially driving conditions with a comparable low exhaust gas mass flow and high oxygen content like idle speed may create a thermal shock. This paper presents a concept for an ECU software structure to prevent the DPF from reaching improper temperatures and the methodology in order to calibrate this ECU structure. The concept deals in general with a closed-loop control of the exhaust gas air-fuel-ratio during the critical engine operation phases. Those critical operation phases are identified at the engine test bench during “Drop-to-Idle” and “Drop-to-Overrun” experiments. The experiments show that those phases are critical having on the one hand a low exhaust gas mass flow and on the other hand a high oxygen percentage in the exhaust gas.

Demand for transport energy is growing but this growth is skewed heavily toward commercial transport, such as, heavy road, aviation, marine and rail which uses heavier fuels like diesel and kerosene. This is likely to lead to an abundance and easy availability of lighter fractions like naphtha, which is the product of the initial distillation of crude oil. Naphtha will also require lower energy to produce and hence will have a lower CO₂ impact compared to diesel or gasoline. It would be desirable to develop engine combustion systems that could run on naphtha. Many recent studies have shown that running compression ignition engines on very low Cetane fuels, which are very similar to naphtha in their auto-ignition behavior, offers the prospect of developing very efficient, clean, simple and cheap engine combustion systems. Significant development work would be required before such systems could power practical vehicles.

The limited availability of fossil fuels and the increasing environmental pollution will lead to an increased demand for sustainable biofuels. The production of bio-based diesel fuels from vegetable oils is commonly accomplished using a process known as Trans-esterification. The product of Transesterification is Fatty Acid Methyl Ester (FAME), commonly known as Biodiesel. An alternative process is Hydro-treatment of seed oils or animal waste fats to produce highly paraffinic renewable diesel fuel called Hydrogenated Vegetable Oil (HVO). Detailed investigations were carried out by the “Department of Advanced Diesel Engine Development” at FEV GmbH Aachen (Germany), to explore the potential of this biofuel compound as a candidate for future compression ignition engines.

This work is a continuation of earlier results presented by the authors. In the current investigations the biofuels hydrogenated vegetable oil (HVO) and 1-octanol are investigated as pure components and compared to EN 590 Diesel. In a final step both biofuels are blended together in an appropriate ratio to tailor the fuels properties in order to obtain an optimal fuel for a clean combustion. The results of pure HVO indicate a significant reduction in CO-, HC- and combustion noise emissions at constant NOX levels. With regard to soot emissions, at higher part loads, the aromatic free, paraffinic composition of HVO showed a significant reduction compared to EN 590 petroleum Diesel fuel. But at lower loads the high cetane number leads to shorter ignition delays and therefore, ignition under richer conditions.

The current and future restrictions on pollutant emissions from internal combustion engines require a holistic investigation of the abilities of alternative fuels to optimize the combustion process and ensure cleaner combustion. In this regard, the Tailor-made Fuels from Biomass (TMFB) Cluster at Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University aims at designing production processes for biofuels as well as fuels optimal for use in internal combustion engines. The TMFB Cluster's scientific approach considers the molecular structure of the fuels as an additional degree of freedom for the optimization of both the production pathways and the combustion process of such novel biofuels. Thus, the model-based specification of target parameters is of the utmost importance to improve engine combustion performance and to send feedback information to the biofuel production process.

The present work is a continuation of the earlier published results by authors on the investigation of Hydrogenated Vegetable Oil (HVO) on a High Efficiency Diesel Combustion System (SAE Int. J. Fuels Lubr. Paper No. 2013-01-1677 and JSAE Paper No. 283-20145128). In order to further validate and interpret the previously published results of soot microstructure and its consequences on oxidation behavior, the test program was extended to analyze the impact of soot composition, optical properties, and physical properties such as size, concentration etc. on the oxidation behavior. The experiments were performed with pure HVO as well as with petroleum based diesel and today's biofuel (i.e. FAME) as baseline fuels. The soot samples for the different analyses were collected under constant engine operating conditions at indicated raw NOx emissions of Euro 6 level using closed loop combustion control methodology.

In recent years, more attention has been focused on environment pollution and energy source issues. As a result, increasingly stringent fuel consumption and emission legislations have been implemented all over the world. For automakers, enhancing engine’s efficiency as a must contributes to lower vehicle fuel consumption. To reach this goal, Geely auto started the development of a 3-cylinder 1.0L turbocharged direct injection (TGDI) gasoline engine to achieve a challenging fuel economy target while maintaining fun-to-drive and NVH performance. Demanding development targets for performance (specific torque 205Nm/L and specific power 100kW/L) and excellent part-load BSFC were defined, which lead to a major challenge for the design of the combustion system. Considering air/fuel mixture, fuel wall impingement and even future potential for lean burn combustion, a symmetrical layout and a central position for the injector with 200bar injection pressure was determined.

Improvements in the efficiency of internal combustion engines has led to a reduction in exhaust gas temperatures. The simultaneous tightening of exhaust emission limits requires ever more complex emission control methods, including aftertreatment whose efficiency is crucially dependent upon the exhaust gas temperature. Double-walled (also called air-gap) exhaust manifold and turbine housing modules made from sheet metal have been used in gasoline engines since 2009. They offer the potential in modern Diesel engines to reduce both the emissions of pollutants and fuel consumption. They also offer advantages in terms of component weight and surface temperatures in comparison to cast iron components. A detailed analysis was conducted to investigate the potential advantages of insulated exhaust systems for modern diesel engines equipped with DOC and SCR coated DPF (SDPF).

Gasoline Controlled Auto Ignition offers a high CO2 emission reduction potential, which is comparable to state-of-the-art, lean stratified operated gasoline engines. Contrary to the latter, GCAI low temperature combustion avoids NOX emissions, thereby trying to avoid extensive exhaust aftertreatment. The challenges remain in a restricted operation range due to combustion instabilities and a high sensitivity towards changing boundary conditions like ambient temperature, intake pressure or fuel properties. Once combustion shows instability, cyclic fluctuations are observed. These appear to have near-chaotic behavior but are characterized by a superposition of clearly deterministic and stochastic effects. Previous works show that the fluctuations can be predicted precisely when taking cycle-tocycle correlations into account. This work extends current approaches by focusing on additional dependencies within one single combustion cycle.

In meeting the stringent emission norms with internal engine measures, the design of the piston bowl and the nozzle configuration perform a defining role. Through 3D CFD simulations, this article shall parametrically investigate the influence of piston bowl geometry and nozzle characteristics on the performance of the combustion system. After validation of the 3D simulation model with experimental results, a Design of Experiment (DoE) method shall be applied to analyze a matrix of piston bowls with parametric variations in geometry. Further, the influence of the nozzle cone angle, hydraulic flow rate, number of holes and their combination shall be determined using systematic parameter variations with selected piston bowl designs. The performance of the various hardware configurations would be evaluated based on the exhaust emissions and fuel consumption values.

For on- and off-highway applications in 2012/2014 new legislative emissions requirements will be applied for both European (EURO 6/stage 4) and US (US 2010/Tier4 final) standards. Specifically the NOX-emission limit will be lowered down to 0.46 g/kWh (net power ≻ 56 kW (EU)/130 kW (US) - 560 kW). While for the previous emissions legislation various ways could be used to stay within the emissions limits (engine internal and aftertreatment measures), DeNOX-aftertreatment systems will be mandatory to reach future limits. In these kinds of applications fuel consumption of the engines is a very decisive selling argument for customers. Total cost of ownership needs to be as low as possible. The trade-off between fuel consumption and NOX emissions forces manufacturers to find an optimal solution, especially with regard to increasing fuel prices. In state-of-the-art calibration processes the aftertreatment system is considered separately from the calibration of the thermodynamics.

Besides an excellent driving performance and power output the reduction of CO2 emission is one of the main driver for the increasing distribution of modern diesel engines. Downsizing/downspeeding, friction reduction, new combustion processes and light weight engine architecture describe additional improvement potentials. Nevertheless, these development trends have a significant influence on the noise and vibration behavior of diesel engines. Therefore measures are also necessary to compensate these acoustic disadvantages. Within this publication the most important and efficient countermeasures are described and assessed. Combustion is still one of the dominant noise sources of a modern diesel engine. Diesel knocking is annoying and the combustion noise level is typically higher than for gasoline engines.

The electrification of vehicle propulsion has changed the landscape of vehicle NVH. Pure electric vehicles (EV) are almost always quieter than those powered by internal combustion engines. However, one of the key challenges with the development of range extended electric vehicles (ReEV) is the NVH behavior of the vehicle. Specifically, the transition from the EV mode to one where the range extender engine is operational can cause significant NVH issues. In addition, the operation of the range extender engine relative to various driving conditions can also pose significant NVH concerns. In this paper internal combustion engines are examined in terms of their acoustic behavior when used as range extenders. This is done by simulating the vibrations at the engine mounting positions as well as the intake and exhaust orifice noise. By using a transfer path synthesis, interior noise components of the range extenders are calculated from these excitations.