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Journal Article

Development and Demonstration of LNT+SCR System for Passenger Car Diesel Applications

2014-04-01
2014-01-1537
The regulations for mobile applications will become stricter in Euro 6 and further emission levels and require the use of active aftertreatment methods for NOX and particulate matter. SCR and LNT have been both used commercially for mobile NOX removal. An alternative system is based on the combination of these two technologies. Developments of catalysts and whole systems as well as final vehicle demonstrations are discussed in this study. The small and full-size catalyst development experiments resulted in PtRh/LNT with optimized noble metal loadings and Cu-SCR catalyst having a high durability and ammonia adsorption capacity. For this study, an aftertreatment system consisting of LNT plus exhaust bypass, passive SCR and engine independent reductant supply by on-board exhaust fuel reforming was developed and investigated. The concept definition considers NOX conversion, CO2 drawback and system complexity.
Journal Article

Contribution of High Accuracy Temperature Sensors Towards Fuel Economy and Robust Calibration

2014-04-01
2014-01-1548
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.
Journal Article

Effects of Mixture Stratification on Ignition and Combustion in a GCAI Engine

2014-04-01
2014-01-1270
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.
Journal Article

Automated Verification and Validation Methods for Transmission Control Software

2015-04-14
2015-01-0163
With the increasing popularity of seamless gear changing and smooth driving experience along with the need for high fuel efficiency, transmission system development has rapidly increased in complexity. So too has transmission control software while quality requirements are high and time-to-market is short. As a result, extensive testing and documentation along with quick and efficient development methods are required. FEV responds to these challenges by developing and integrating a transmission software product line with an automated verification and validation process according to the concept of Continuous Integration (CI). Hence, the following paper outlines a software architecture called “PERSIST” where complexity is reduced by a modular architecture approach. Additionally, modularity enables testability and tracking of quality defects to their root cause.
Journal Article

Cylinder Pressure Based Fuel Path Control for Non-Conventional Combustion Modes

2015-09-06
2015-24-2508
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.
Journal Article

A Sectoral Approach to Modelling Wall Heat Transfer in Exhaust Ports and Manifolds for Turbocharged Gasoline Engines

2016-04-05
2016-01-0202
A new approach is presented to modelling wall heat transfer in the exhaust port and manifold within 1D gas exchange simulation to ensure a precise calculation of thermal exhaust enthalpy. One of the principal characteristics of this approach is the partition of the exhaust process in a blow-down and a push-out phase. In addition to the split in two phases, the exhaust system is divided into several sections to consider changes in heat transfer characteristics downstream the exhaust valves. Principally, the convective heat transfer is described by the characteristic numbers of Nusselt, Reynolds and Prandtl. However, the phase individual correlation coefficients are derived from 3D CFD investigations of the flow in the exhaust system combined with Low-Re turbulence modelling. Furthermore, heat losses on the valve and the seat ring surfaces are considered by an empirical model approach.
Journal Article

Influence of Advanced Technology for Thermal Management on SUV

2016-04-05
2016-01-0238
Reducing fuel consumption is a major challenge for vehicle, especially for SUV. Cooling loss is about 30% in total energy loss under NEDC (New European Driving Cycle) cycle. It is necessary to optimize vehicle thermal management system to improve fuel economy. Otherwise, rapid warm-up is beneficial for friction reduction and passenger comfort in cold-start. Vehicle thermal behavior is influenced by cooling system layout, new technology and control strategy. Thermal management simulation is effective to show the energy flow and fuel consumption under the influence of new technology under NEDC cycle. So 1D thermal management simulation model is created, including vehicle, cooling system, lubrication system and detailed engine model with all friction components. And the interrelations between all the components are considered in the model. For model calibration, large amount of data is obtained from vehicle tests such as transient fuel consumption and transient coolant temperature.
Journal Article

Thermal Shock Protection for Diesel Particulate Filters

2011-12-15
2011-01-2429
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.
Journal Article

Optimization of Electrified Powertrains for City Cars

2012-06-01
2011-01-2451
Sustainable and energy-efficient consumption is a main concern in contemporary society. Driven by more stringent international requirements, automobile manufacturers have shifted the focus of development into new technologies such as Hybrid Electric Vehicles (HEVs). These powertrains offer significant improvements in the efficiency of the propulsion system compared to conventional vehicles, but they also lead to higher complexities in the design process and in the control strategy. In order to obtain an optimum powertrain configuration, each component has to be laid out considering the best powertrain efficiency. With such a perspective, a simulation study was performed for the purpose of minimizing well-to-wheel CO2 emissions of a city car through electrification. Three different innovative systems, a Series Hybrid Electric Vehicle (SHEV), a Mixed Hybrid Electric Vehicle (MHEV) and a Battery Electric Vehicle (BEV) were compared to a conventional one.
Journal Article

7-XDCT: Compact and Cost-Efficient Dual Clutch Transmission for Small and Mid-Size Vehicles

2013-04-08
2013-01-1271
The automotive industry continues to develop new powertrain technologies aimed at reducing overall vehicle level fuel consumption. The ongoing trends of “downsizing” and “down speeding” have led to the development of turbocharged engines with low displacement and high torque density. In order to meet the launch response requirements with these engines as well as fuel economy needs, transmissions with large ratio spreads will need to be developed. Due to the lack of torque amplification from the torque converter, the next generation of dual clutch transmissions (DCT) will need to have larger launch ratios and ratio spreads than currently available in production today. This paper discusses the development of a new family of DCT (called “xDCT”) for use in front wheel drive vehicles, aimed at meeting some of these challenges. The xDCT family features two innovative concepts, the idea of “gear generation” and “supported shifts”.
Journal Article

Performance Plus Range: Combined Battery Concept for Plug‑In Hybrid Vehicles

2013-04-08
2013-01-1525
PlugIn Hybrid Electric Vehicles (PHEV) offer the opportunity to experience electric driving without the risk of vehicle break-down due to a low battery charge state. Thus, PHEV's represent an attractive means of meeting future CO2-legislation. PHEV batteries must fulfill a divergent list of requirements: on the one hand, the battery must supply sufficient energy to ensure it can be driven an appropriate distance in EV-mode. On the other hand, even with a low state-of-charge (SOC), the battery must supply sufficient power to assist the engine in vehicle acceleration or to recuperate on deceleration. This leads to a compromise in terms of cell selection. Fundamentally, high energy cells cannot provide high charge and discharge rates and high power cells cannot provide sufficient energy.
Journal Article

Impact of Biomass-Derived Fuels on Soot Oxidation and DPF Regeneration Behavior

2013-04-08
2013-01-1551
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.
Technical Paper

Tuning and Validation of DPF for India Market

2017-01-10
2017-26-0135
In a move to curb vehicular pollution, Indian Government decided to bring forward the date for BSVI standards into effect from April 2020 while skipping the intermediate BSV stage. The plan to implement BSVI norms, which initially was scheduled for 2024 according to the National Auto Fuel Policy dated April 27, 2015, has now been slotted for April 2020. For particulate mass (PM) emissions to be brought down to the BS VI level (4.5mg/km), diesel passenger cars need to be fitted with a diesel particulate filter (DPF). The diesel particulate filter (DPF) is a device designed to remove soot from the exhaust gas of the diesel engine. DPF must be cleaned/regenerated from time to time else, it will block up. Optimized DPF calibration is the key for various challenges linked with its use as one of the effective PM reduction technology.
Technical Paper

Development of Combustion System for a 1-Liter Advanced Turbocharged Gasoline Direct Injection 3-Cylinder Engine

2016-10-17
2016-01-2243
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.
Technical Paper

Investigation of Insulated Exhaust Manifolds and Turbine Housings in Modern Diesel Engines for Emissions and Fuel Consumption Reduction

2016-04-05
2016-01-1003
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).
Technical Paper

Meeting 2025 CAFE Standards for LDT with Fuel-Efficient Diesel Powertrains - Approaches and Solutions

2017-03-28
2017-01-0698
In view of changing climatic conditions all over the world, Green House Gas (GHG) saving related initiatives such as reducing the CO2 emissions from the mobility and transportation sectors have gained in importance. Therefore, with respect to the large U.S. market, the corresponding legal authorities have defined aggressive and challenging targets for the upcoming time frame. Due to several aspects and conditions, like hesitantly acting clients regarding electrically powered vehicles or low prices for fossil fuels, convincing and attractive products have to be developed to merge legal requirements with market constraints. This is especially valid for the market segment of Light-Duty vehicles, like SUV’S and Pick-Up trucks, which are in high demand.
Technical Paper

1D Engine Simulation Approach for Optimizing Engine and Exhaust Aftertreatment Thermal Management for Passenger Car Diesel Engines by Means of Variable Valve Train (VVT) Applications

2018-04-03
2018-01-0163
Using a holistic 1D engine simulation approach for the modelling of full-transient engine operation, allows analyzing future engine concepts, including its exhaust gas aftertreatment technology, early in the development process. Thus, this approach enables the investigation of both important fields - the thermodynamic engine process and the aftertreatment system, together with their interaction in a single simulation environment. Regarding the aftertreatment system, the kinetic reaction behavior of state-of-the-art and advanced components, such as Diesel Oxidation Catalysts (DOC) or Selective Catalytic Reduction Soot Filters (SCRF), is being modelled. Furthermore, the authors present the use of the 1D engine and exhaust gas aftertreatment model on use cases of variable valve train (VVT) applications on passenger car (PC) diesel engines.
Technical Paper

Comparison of Model Predictions with Temperature Data Sensed On-Board from the Li-ion Polymer Cells of an Electric Vehicle

2012-05-15
2011-01-2443
One of the challenges faced when using Li-ion batteries in electric vehicles is to keep the cell temperatures below a given threshold. Mathematical modeling would indeed be an efficient tool to test virtually this requirement and accelerate the battery product lifecycle. Moreover, temperature predicting models could potentially be used on-board to decrease the limitations associated with sensor based temperature feedbacks. Accordingly, we present a complete modeling procedure which was used to calculate the cell temperatures during a given electric vehicle trip. The procedure includes a simple vehicle dynamics model, an equivalent circuit battery model, and a 3D finite element thermal model. Model parameters were identified from measurements taken during constant current and pulse current discharge tests. The cell temperatures corresponding to an actual electric vehicle trip were calculated and compared with measured values.
Technical Paper

Traction Battery and Battery Control Unit Development

2012-04-16
2012-01-0122
The performance of high voltage batteries is the key factor for further success of electric vehicles. The primary areas for battery development include high voltage (HV) and functional safety, maximum power and usable energy, battery life, packaging and weight reduction. This paper explains the development of the HV battery and the battery management system for the FEV Liona fleet, a retrofit of a pure electric powertrain into a FIAT 500. The multi-disciplinary process used to develop this program includes electrical, mechanical and functional aspects. The layout of the electrical system includes cell selection, layout of modules and the interconnection of twelve modules to a battery pack. The mechanical design of mounting the battery under the floor addresses the housing issues regarding robustness and sealing, the packaging into the vehicle as well as the positioning of the HV components inside the battery.
Technical Paper

The NVH Behavior of Internal Combustion Engines used in Range Extended Electric Vehicles

2013-05-13
2013-01-2002
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.
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