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A Quasi-Dimensional Model of Pre-Chamber Spark-Ignition Engines

VKA, RWTH Aachen University-Christoph Müller
FEV Engine Technology-Knut Habermann
Published 2019-04-02 by SAE International in United States
Increasingly stringent pollutant and CO2 emission standards require the car manufacturers to investigate innovative solutions to further improve the fuel economy of their fleets. Among these techniques, an extremely lean combustion has a large potential to simultaneously reduce the NOx raw emissions and the fuel consumption of spark-ignition engines. Application of pre-chamber ignition systems is a promising solution to realize a favorable air/fuel mixture ignitability and an adequate combustion speed, even with very lean mixtures.In this work, the combustion characteristics of an active pre-chamber system are experimentally investigated using a single-cylinder research engine. Conventional gasoline fuel is injected into the main chamber, while the pre-chamber is fed with compressed natural gas. In a first stage, an experimental campaign was carried out at various speeds, spark timings and air-fuel ratios. Global engine operating parameters as well as cylinder pressure traces, inside main combustion chamber and pre-chamber, were recorded and analyzed.Based on the available experimental data, a phenomenological model of this unconventional combustion system with divided combustion chambers was developed and validated. The model was then implemented…
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Experimental Investigations on the Influence of Valve Timing and Multi-Pulse Injection on GCAI Combustion

VKA, RWTH Aachen University-Bastian Lehrheuer, Stefan Pischinger
Indian Institute of Technology Madras-Jensen Samuel, Santhosh Mithun, Kasinath Panda, A Ramesh
Published 2019-04-02 by SAE International in United States
Gasoline Controlled Auto-Ignition (GCAI) combustion, which can be categorized under Homogeneous Charge Compression Ignition (HCCI), is a low-temperature combustion process with promising benefits such as ultra-low cylinder-out NOx emissions and reduced brake-specific fuel consumption, which are the critical parameters in any modern engine. Since this technology is based on uncontrolled auto-ignition of a premixed charge, it is very sensitive to any change in boundary conditions during engine operation. Adopting real time valve timing and fuel-injection strategies can enable improved control over GCAI combustion. This work discusses the outcome of collaborative experimental research by the partnering institutes in this direction. Experiments were performed in a single cylinder GCAI engine with variable valve timing and Gasoline Direct Injection (GDI) at constant indicated mean effective pressure (IMEP). In the first phase intake and exhaust valve timing sweeps were investigated. It was found that the Intake Valve Closing (IVC) timing and Exhaust Valve Closing (EVC) timing have a dominant influence on combustion, performance and emission parameters.In the second phase of experiments, multiple injection strategies were investigated. Here the influences…
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Effect of Engine Operating Parameters on Space- and Species-Resolved Measurements of Engine-Out Emissions from a Single-Cylinder Spark Ignition Engine

VKA, RWTH Aachen University-Stefania Esposito, Peter Mauermann, Bastian Lehrheuer, Marco Günther, Stefan Pischinger
Published 2019-04-02 by SAE International in United States
The development and validation of detailed simulation models of in-cylinder combustion, emission formation mechanisms and reaction kinetics in the exhaust system are of crucial importance for the design of future low-emission powertrain concepts. To investigate emission formation mechanisms on one side and to create a solid basis for the validation of simulation methodologies (e.g. 3D-CFD, multi-dimensional in-cylinder models, etc.) on the other side, specific detailed measurements in the exhaust system are required. In particular, the hydrocarbon (HC) emissions are difficult to be investigated in simulation and experimentally, due to their complex composition and their post-oxidation in the exhaust system.In this work, different emission measurement devices were used to track the emission level and composition at different distances from the cylinder along the exhaust manifold, from the exhaust valve onwards. A fast-FID (FFID) was used to measure the cycle-resolved total-HC (THC) emissions and an ion molecule reaction mass-spectrometer (IMR-MS) to determine the average concentration of some selected HC components. Conventional exhaust analyzers were used additionally to measure the average levels of the important exhaust gas components…
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Coupled Dynamic Simulation of Two Stage Variable Compression Ratio (VCR) Connecting Rod Using Virtual Dynamics

SAE International Journal of Advances and Current Practices in Mobility

VKA, RWTH Aachen University-Denis Pendovski
FEV Europe GmbH-Sebastian Sonnen, Alexander Uhlmann, Daniel Henaux
  • Journal Article
  • 2019-26-0031
Published 2019-01-09 by SAE International in United States
The fuel consumption of combustion engines requires continuous reduction to meet future CO2 fleet targets. The progression of emission legislations shifted the focus on PN and NOX emissions in real world driving scenarios (RDE). Recently, the monitoring of CO emissions puts high load fuel enrichment for component protection into focus and a ban on enrichment is widely expected. Hence, gasoline engine technologies, which enable Lambda 1 operation in the entire engine map are specifically promoted. Variable Compression Ratio (VCR) attacks all these topics already at the combustion process. In addition to the well-known CO2 capability, VCR also enables enlargement of the lambda 1 operation in gasoline engines as well as reduced NOX emissions in diesel engines. The basic principle of developed VCR solution is to change the effective length of the connecting rod (and thereby the compression ratio) in two stages by several millimeters. Basically, the VCR connecting rod consists of a mechanical and hydraulic system which is fed with oil by the connecting rod bearing. All functional elements to realize the variability such as…
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On Board Diagnostics (OBD) for Multi Topology Hybrid Electric Powertrain Architectures

VKA, RWTH Aachen University-Ragupathi Soundara Rajan
FEV Europe GmbH-Felix Richert, Dirk Van Der Weem
Published 2018-09-10 by SAE International in United States
OBD is extended to electric powertrain components in Hybrid Electric Vehicle (HEV) architectures to monitor all components which influence vehicle emissions and electrical energy consumption. Besides main electric components, like battery, inverter, electric machines including their thermal management, other electric powertrain components and systems need to be evaluated as part of comprehensive component monitoring. The multiple possible HEV topologies require a complex assessment regarding the OBD relevance decisions of the electric drivetrain components or systems. In addition, specificities to OBD perimeter design in the hybrid architecture need to be appropriately chosen. This paper analyzes in detail the OBD regulation requirements for electric propulsion components as in the US regulation, which is an envelope for major global markets like Europe, China, Japan and Korea. Typical hybrid topologies from the literature and FEV’s comprehensive library are used as citation in this study. The monitors from these topologies are assessed for OBD relevance based on regulation requirements and the approach is detailed in this paper. The assessment is extended to safety relevant monitors, which are not part of…
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Evaluation of the Potential of Water Injection for Gasoline Engines

SAE International Journal of Engines

VKA, RWTH Aachen University-Fabian Hoppe
FEV Europe GmbH-Matthias Thewes, Joerg Seibel, Andreas Balazs, Johannes Scharf
  • Journal Article
  • 2017-24-0149
Published 2017-09-04 by SAE International in United States
Gasoline engine powertrain development for 2025 and beyond is focusing on finding cost optimal solutions by balancing electrification and combustion engine efficiency measures. Besides Miller cycle application, cooled exhaust gas recirculation and variable compression ratio, the injection of water has recently gained increased attention as a promising technology for significant CO2 reduction. This paper gives deep insight into the fuel consumption reduction potential of direct water injection. Single cylinder investigations were performed in order to investigate the influence of water injection in the entire engine map. In addition, different engine configurations were tested to evaluate the influence of the altering compression ratios and Miller timings on the fuel consumption reduction potential with water injection. Based on the single cylinder investigations, drive cycle simulations covering a low, intermediate, and high load profiles were performed to evaluate the fuel consumption reduction potential as well as the corresponding water consumption under varying load demands for the different engine configurations. Furthermore, these simulations were used to optimize the water injection rate for the altering boundary conditions regarding the trade-off…
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Next-Generation Low-Voltage Power Nets Impacts of Advanced Stop/Start and Sailing Functionalities

SAE International Journal of Fuels and Lubricants

VKA, RWTH Aachen University-Philip Griefnow, Jakob Andert
FEV GmbH-Dejan Jolovic
  • Journal Article
  • 2017-01-0896
Published 2017-03-28 by SAE International in United States
The range of tasks in automotive electrical system development has clearly grown and now includes goals such as achieving efficiency requirements and complying with continuously reducing CO2 limits. Improvements in the vehicle electrical system, hereinafter referred to as the power net, are mandatory to face the challenges of increasing electrical energy consumption, new comfort and assistance functions, and further electrification. Novel power net topologies with dual batteries and dual voltages promise a significant increase in efficiency with moderate technological and financial effort. Depending on the vehicle segment, either an extension of established 12 V micro-hybrid technologies or 48 V mild hybridization is possible.Both technologies have the potential to reduce fuel consumption by implementing advanced stop/start and sailing functionalities. Additional engine-stop phases and even reduced driving resistance have positive impacts on the fuel consumption but lead to higher load on the electrical system and an energy deficit by reducing the recuperation and charging phases. Therefore, power net architecture and electrical energy management play an essential role with regard to safety and efficiency issues.The first step of…
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Future Specification of Automotive LPG Fuels for Modern Turbocharged DI SI Engines with Today’s High Pressure Fuel Pumps

SAE International Journal of Fuels and Lubricants

VKA, RWTH Aachen University-Martin Krieck, Marco Günther, Stefan Pischinger
FEV GmbH-Matthias Thewes
  • Journal Article
  • 2016-01-2255
Published 2016-10-17 by SAE International in United States
Liquefied Petroleum Gas direct injection (LPG DI) is believed to be the key enabler for the adaption of modern downsized gasoline engines to the usage of LPG, since LPG DI avoids the significant low end torque drop, which goes along with the application of conventional LPG port fuel injection systems to downsized gasoline DI engines, and provides higher combustion efficiencies. However, especially the high vapor pressure of C3 hydrocarbons can result in hot fuel handling issues as evaporation or even in reaching the supercritical state of LPG upstream or inside the high pressure pump (HPP). This is particularly critical under hot soak conditions. As a result of a rapid fuel density drop close to the supercritical point, the HPP is not able to keep the rail pressure constant and the engine stalls. Thus, in order to enable wider use of LPG and to assist the process of standardization, a limitation for maximum content of C3 fuel components - as propane and propene - is required as a key enabler for LPG DI applications. In order…
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Impact of Biomass-Derived Fuels on Soot Oxidation and DPF Regeneration Behavior

SAE International Journal of Fuels and Lubricants

VKA, RWTH Aachen University-Om Parkash Bhardwaj, Florian Kremer, Stefan Pischinger
FEV GmbH-Bernhard Lüers, Andreas F. Kolbeck, Thomas Koerfer
  • Journal Article
  • 2013-01-1551
Published 2013-04-08 by SAE International in United States
To comply with the new regulations on particulate matter emissions, the manufacturers of light-duty as well as heavy-duty vehicles more commonly use diesel particulate filters (DPF). The regeneration of DPF depends to a significant extent on the properties of the soot stored.Within the Cluster of Excellence "Tailor-Made Fuels from Biomass (TMFB)" at RWTH Aachen University, the Institute for Combustion Engines carried out a detailed investigation program to explore the potential of future biofuel candidates for optimized combustion systems. The experiments for particulate measurements and analysis were conducted on a EURO 6-compliant High Efficiency Diesel Combustion System (HECS) with petroleum-based diesel fuel as reference and a today's commercial biofuel (i.e., FAME) as well as a potential future biomass-derived fuel candidate (i.e., 2-MTHF/DBE).Thermo gravimetric analyzer (TGA) was used in this study to evaluate the oxidative reactivity of the soot. A "Laboratory Gas Test Bench (LGB)" was used to determine the kinetics of soot oxidation mechanism considering impact of soot properties on its burning behavior inside a DPF. The kinetics of soot oxidation with O₂ was studied as…
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Influence of the Combination of Fuel Properties for a DI-Diesel Engine Under Partly Homogeneous Combustion

VKA, RWTH Aachen University-Stefan Pischinger
FEV GmbH, Aachen, Germany-Yousef Jeihouni, Ludger Ruhkamp
Published 2013-04-08 by SAE International in United States
Partly homogeneous combustion (PHC) can assist the reduction of the engine-out emissions but its influence is limited by using conventional diesel fuel. To verify whether alternatively designed fuels can help to improve the PHC performance, the impact of different fuel properties in combination with engine control levers have been studied.Based on single cylinder heavy duty direct injection diesel engine (DIDE) test results with different diesel and diesel-like fuels, operating under partly homogeneous combustion conditions, the impact of the combination of the fuel properties were investigated.The fuel matrix was designed such that the fuel properties varied in sufficiently large ranges, in order to be able to detect the impact of the properties at the selected operating points. A statistical principal component analysis (PCA) has been applied to the fuel matrix to specify the interrelationship between the fuel properties, as well as to derive the most independent fuel properties. The analyses have been performed at some representative points of the engine map, with regard to the impact of the changes in fuel properties on the emission results.…
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