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Technical Paper

Super Ultra-Low NOX Emissions under Extended RDE Conditions - Evaluation of Light-Off Strategies of Advanced Diesel Exhaust Aftertreatment Systems

2019-04-02
2019-01-0742
Super ultra-low NOX emission engine concepts are essential to comply with future emission legislations. To meet the future emission standards, application of advanced diesel exhaust aftertreatment systems (EATS), such as Diesel Oxidation Catalyst (DOC), Lean NOX Trap (LNT), Selective Catalytic Reduction coatings on Soot Filters (SCRF) and underfloor SCR, is required. Effective customized thermal management strategies are essential to ensure fast light-off of the EATS after engine cold start, and to avoid significant cooldown during part load operation. The authors describes the investigation of different exhaust gas heating measures, such as intake throttling, late fuel injection, exhaust throttling, advanced exhaust cam phasing, retarded intake cam phasing, cylinder deactivation, full turbine bypass, electric catalyst heating and electrically heated intake manifold strategies.
Technical Paper

Accurate Mean Value Process Models for Model-Based Engine Control Concepts by Means of Hybrid Modeling

2019-04-02
2019-01-1178
Advanced powertrains for modern vehicles require the optimization of conventional combustion engines in combination with tailored electrification and vehicle connectivity strategies. The resulting systems and their control devices feature many degrees of freedom with a large number of available adjustment parameters. This obviously presents major challenges to the development of the corresponding powertrain control logics. Hence, the identification of an optimal system calibration is a non-trivial task. To address this situation, physics-based control approaches are evolving and successively replacing conventional map-based control strategies in order to handle more complex powertrain topologies. Physics-based control approaches enable a significant reduction in calibration effort, and also improve the control robustness.
Technical Paper

Bharat Stage-V Solutions for Agricultural Engines for India Market

2019-01-09
2019-26-0148
The Bharat Stage (CEV/Tractor) IV & V emission legislations will come into force in Oct 2020 & Apr 2024 respectively, posing a major engineering challenge in terms of system complexity, reliability, costs and development time. Solutions for the EU Stage-V NRMM legislation in Europe, from which the BS-V limits are derived, have been developed and are ready for implementation. To a certain extent these European solutions can be transferred to the Indian market. However, certain market-specific challenges are yet to be defined and addressed. In addition, a challenging timeline has to be considered for application of advanced technologies and processes during the product development. In this presentation, the emission roadmap will be introduced in the beginning, followed by a discussion of potential technology solutions on the engine itself as well as on the after treatment components.
Technical Paper

Development of a New 1.8L Down-Speeding Turbocharged Gasoline Engine with Miller Cycle

2018-09-10
2018-01-1712
Upcoming China 4th stage of fuel consumption regulation and China 6a emission legislation require improvement of many existing engines. This paper summarizes an upgrade of combustion system and mechanical layout for a four-cylinder engine family. Based on an existing production process for a naturally aspirated 2.0-liter gasoline engine, a 1.8-liter down-speeded and turbocharged gasoline engine is derived. Starting development by analysis of engine base geometry, a layout for a Miller-Cycle gas exchange with early closing of intake valves is chosen. Requirements on turbocharger configuration are investigated with one-dimensional gas exchange simulation and combustion process will be analyzed by means of 3D-CFD simulation. Challenging boundary conditions of a very moderate long-stroke layout with a stroke/bore-ratio of only 1.037 in combination with a cost efficient port fuel injection system and fixed valve lift profiles are considered.
Technical Paper

In-Use Compliance Opportunity for Diesel Powertrains

2018-04-03
2018-01-0877
In-use compliance under LEV III emission standards, GHG, and fuel economy targets beyond 2025 poses a great opportunity for all ICE-based propulsion systems, especially for light-duty diesel powertrain and aftertreatment enhancement. Though diesel powertrains feature excellent fuel-efficiency, robust and complete emissions controls covering any possible operational profiles and duty cycles has always been a challenge. Significant dependency on aftertreatment calibration and configuration has become a norm. With the onset of hybridization and downsizing, small steps of improvement in system stability have shown a promising avenue for enhancing fuel economy while continuously improving emissions robustness. In this paper, a study of current key technologies and associated emissions robustness will be discussed followed by engine and aftertreatment performance target derivations for LEV III compliant powertrains.
Technical Paper

λDSF: Dynamic Skip Fire with Homogeneous Lean Burn for Improved Fuel Consumption, Emissions and Drivability

2018-04-03
2018-01-0891
Dynamic skip fire (DSF) has shown significant fuel economy improvement potential via reduction of pumping losses that generally affect throttled spark-ignition (SI) engines. In DSF operation, individual cylinders are fired on-demand near peak efficiency to satisfy driver torque demand. For vehicles with a downsized-boosted 4-cylinder engine, DSF can reduce fuel consumption by 8% in the WLTC (Class 3) drive cycle. The relatively low cost of cylinder deactivation hardware further improves the production value of DSF. Lean burn strategies in gasoline engines have also demonstrated significant fuel efficiency gains resulting from reduced pumping losses and improved thermodynamic characteristics, such as higher specific heat ratio and lower heat losses. Fuel-air mixture stratification is generally required to achieve stable combustion at low loads.
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.
Journal Article

Metric-based Evaluation of Powertrain Software Architecture

2017-03-28
2017-01-1615
Ensuring software quality is one of the key challenges associated with the development of automotive embedded systems. Software architecture plays a pivotal role in realizing functional and non-functional requirements for automotive embedded systems. Software architecture is a work-product of the early stages of software development. The design errors introduced at the early stages of development will increase cost of rework. Hence, an early evaluation of software architecture is important. PERSIST (Powertrain control architecture Enabling Reusable Software development for Intelligent System Tailoring) is a model-based software product line approach which focuses on cross-project standardization of powertrain software. The product line is characterized by common design guidelines and adherence to industry standards like ISO 25010, AUTOSAR and ISO 26262.
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

Bharat Stage VI Solutions for Commercial Engines for the India Market

2017-01-10
2017-26-0043
The Bharat Stage VI (BS-VI) emission legislation will come into force in 2020, posing a major engineering challenge in terms of system complexity, reliability, cost and development time. Solutions for the EURO VI on-road legislation in Europe, from which the BS-VI limits are derived, have been developed and have already been implemented. To a certain level these European solutions can be transferred to the Indian market. However, several market-specific challenges are yet to be defined and addressed. In addition, a very strict timeline has to be considered for application of advanced technologies and processes during the product development. In this paper, the emission roadmap will be introduced in the beginning, followed by a discussion of potential technology solutions on the engine itself as well as on the exhaust aftertreatment side. This includes boosting and fuel injection technologies as well as different exhaust gas recirculation methods.
Technical Paper

Efficient Dual Clutch Transmission Family for Transversal, Transaxle Powertrains

2017-01-10
2017-26-0036
The reduction of CO2 emissions at vehicle level through the improvement of transmission efficiency represents the essential goal of transmission development engineers. New requirements, such as the recovery of the kinetic energy of the vehicle while coasting, the hybridization of drivetrains and autonomous driving, are challenges that can best be overcome with automatic transmissions. Dual clutch transmissions (DCT) with power-on-demand actuation systems offer a particularly efficient method of meeting the new requirements. However, many markets show vehicle applications with production volumes of less than 100.000 units per year. FEV’s new DCT family is conceived especially for customers in these markets. The re-use of proven subsystems which are already in series production results in a "business case" for applications with lower volumes also. This article introduces this transmission family.
Journal Article

Optimization of Exhaust After-Treatment System (EATS) to BS 6 Emission Level for a Light Commercial Vehicle (LCV) Using Existing BS 4 Engine Results and 1-D Simulation Approach

2017-01-10
2017-26-0119
The emission legislations are becoming increasingly strict all over the world and India too has taken a big leap in this direction by signaling the migration from Bharat Stage 4 (BS 4) to BS 6 in the year 2020. This decision by the Indian government has provided the Indian automotive industry a new challenge to find the most optimal solution for this migration, with the existing BS 4 engines available in their portfolio. Indian market for the LCV segment is highly competitive and cost sensitive where the overall vehicle operation cost (vehicle cost + fluid consumption cost) is the most critical factor. The engine and after-treatment technology for BS 6 emission levels should consider the factors of minimizing the additional hardware cost as well as improving the fuel efficiency. Often both of which are inversely proportional. The presented study involves the optimization of after treatment component size, layout and various systems for NOx and PM reduction.
Technical Paper

On-Board Diagnostic Related Challenges on Two-Wheelers Related to the Upcoming Bharat Stage VI Emission Standards

2017-01-10
2017-26-0147
The decision to leapfrog from the Bharat Stage (BS) IV emission standards directly to the BS VI standards not only effects passenger and commercial vehicles but also India’s by far largest vehicle class, with regards to sales and production, the two-wheelers. The BS VI norm will not only tighten the emission standards, but it will also increase the required emission mileage level and upgrade the On-Board Diagnostic (OBD) requirements, also by introducing In-Use Monitor Performance Ratio (IUMPR) standards. While OBD was already introduced for passenger and commercial vehicles with BS IV in 2010, OBD will be then newly introduced for two-wheelers. The OBD system monitors the vehicle’s in-use emission performance, informs the driver via the malfunction indication light (MIL) on the dashboard in case of an emission relevant failure, standardises the diagnostic code handling and regulates a standardised access to the electronic control units (ECUs) for maintenance and inspection purposes.
Technical Paper

Comparative Study to Assess the Potential of Different Exhaust Gas Aftertreatment Concepts for Diesel Powered Ultra-Light Commercial Vehicle Applications in View of Meeting BS VI Legislation

2017-01-10
2017-26-0128
Despite the trend in increased prosperity, the Indian automotive market, which is traditionally dominated by highly cost-oriented producion, is very sensitive to the price of fuels and vehicles. Due to these very specific market demands, the U-LCV (ultra-light commercial vehicle) segment with single cylinder natural aspirated Diesel engines (typical sub 650 cc displacement) is gaining immense popularity in the recent years. By moving to 2016, with the announcement of leapfrogging directly to Bharat Stage VI (BS VI) emission legislation in India, and in addition to the mandatory application of Diesel particle filters (DPF), there will be a need to implement effective NOx aftertreament systems. Due to the very low power-to-weight ratio of these particular applications, the engine operation takes place under full load conditions in a significant portion of the test cycle.
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.
Journal Article

Future Specification of Automotive LPG Fuels for Modern Turbocharged DI SI Engines with Today’s High Pressure Fuel Pumps

2016-10-17
2016-01-2255
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.
Journal Article

Advanced Fuel Formulation Approach using Blends of Paraffinic and Oxygenated Biofuels: Analysis of Emission Reduction Potential in a High Efficiency Diesel Combustion System

2016-10-17
2016-01-2179
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.
Technical Paper

A Study on In-Cycle Combustion Control for Gasoline Controlled Autoignition

2016-04-05
2016-01-0754
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.
Technical Paper

A Simulation Study of Electrically Heating Diesel Exhaust

2016-04-05
2016-01-0927
Modifications have been made to the calibration and control of Diesel engines to increase the temperature of the exhaust especially in cold weather and part load operation. The main purpose for this advanced calibration is to enable the reduction of emissions by improving catalytic activity. An alternative method for increasing exhaust temperature is providing electric heat. Test results show the feasibility of applying various amounts of electric heat and the related increases in exhaust temperature as well as speed of heating. Simulation modeling extends the application of electric heat to a complete engine map and explores the potential impact on engine performance and emission reduction benefits.
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).
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