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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

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

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

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

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

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

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

Bharat Stage VI Solutions for Commercial Engines for the India Market

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

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

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

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

Hybrid Dynamic Analysis of Crankshaft-Crankcase for Off-Road Engine Application

This work presents the results and methodology of a dynamic durability analysis considering the interaction between crankcase and crankshaft. The approach is based on a robust mathematical model that couples the dynamic characteristics of the crankshaft and crankcase, representing the actual interaction between both components. Dynamic loadings generated by the crankshaft are transferred to the crankcase through flexible 3D hydrodynamic bearings. This methodology is referred to as hybrid simulation, which consists in the solution of the dynamics of an Elastic Multi-Body System (E-MBS) coupled with the Finite Element Methodology (FEM). For this study, it was considered an in-line 6-cylinder diesel engine used in off-road applications. The crankcase design must withstand higher loads due to new calibration targets stipulated for PROCONVE (MAR-I) emission regulations.
Technical Paper

Internal and External Measures for Catalyst Light-Off Support

Within a project of the Research Association for Combustion Engines e.V., different measures for rising the temperature of exhaust gas aftertreatment components of both a passenger car and an industrial/commercial vehicle engine were investigated on a test bench as well as in simulation. With the passenger car diesel engine and different catalyst configurations, the potential of internal and external heating measures was evaluated. The configuration consisting of a NOx storage catalyst (NSC) and a diesel particulate filter (DPF) illustrates the potential of an electrically heated NSC. The exhaust aftertreatment system consisting of a diesel oxidation catalyst (DOC) and a DPF shows in simulation how variable valve timing in combination with electric heated DOC can be used to increase the exhaust gas temperature and thus fulfill the EU6 emission limits.
Journal Article

An Experimental Investigation of Dual-Fuel Combustion in a Light Duty Diesel Engine by In-Cylinder Blending of Ethanol and Diesel

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.
Technical Paper

Robust Emission Compliance and Reduction of System Cost by advanced emission-based Diesel engine air management

The continuously strengthened requirements regarding air quality and pollutant reduction as well as GHG emissions further complicate the compliance with legal standards. Especially in view of cost-sensitive applications this demand strongly collides with the EMS set-up and the sensor requirements with still increasing overall system complexity. The paper in hand describes a novel air path control approach, which offers the potential for a flexible use of multiple EGR routes to meet upcoming legislations more robustly, while providing a significant reduction of calibration effort and sensor content at the same time. By using a direct emission based cylinder charge control, also alterations in operational ambient conditions are covered with system reactions according to physical-based rules to enhance the engine-out emission performance without need for tuning of corrections of any air path set point.
Technical Paper

15 Years of Transfer Path Analysis VINS in the Vehicle NVH Development - Selected Results

Transfer path analysis is a powerful tool to support the vehicle NVH development. On the one hand it is a fast method to gain an overview of the complex interplay in the vehicle noise generation process. On the other hand it can be used to identify critical noise paths and vehicle components responsible for specific noise phenomena. FEV has developed several tools, which are adapted to the considered noise phenomena: Powertrain induced interior noise and vibration is analyzed by VINS (Vehicle Interior Noise Simulation), which allows the deduction of improvement measures fast enough for application in the accelerated vehicle development process. Further on vehicle/powertrain combinations not realized in hardware can be evaluated by virtual installation of the powertrain in the vehicle, which is especially interesting in the context of engine downsizing from four to three or six to four cylinders.
Technical Paper

Modelling a Gasoline Compression Ignition (GCI) Engine Concept

Future engines and vehicles will be required to reduce both regulated and CO2 emissions. To achieve this performance, they will be configured with advanced hardware and engine control technology that will enable their operation on a broader range of fuel properties than today. Previous work has shown that an advanced compression ignition bench engine can operate successfully on a European market gasoline over a range of speed/load conditions while achieving diesel-like engine efficiency and acceptable regulated emissions and noise levels. Stable Gasoline CI (GCI) combustion using a European market gasoline was achieved at high to medium engine loads but combustion at lower loads was very sensitive to EGR rates, leading to longer ignition delays and a steep cylinder pressure rise.
Technical Paper

Achieving Optimum Crankshaft Design - I

The increasing pressure on the engine development process via tighter legislations and increasing competition lead to search for the best possible design for each engine component. Especially the dynamic parts, which contribute to total engine friction at most, are under extreme focus. The search for the optimum layout of crankshafts considering the design aims, such as low friction, low weight and high durability, is usually a manual variation process with limited number of design loops. Within this study computer aided (CA) automated optimization methodologies are integrated into the design procedure to achieve the best possible design solution according to the objectives under consideration of the predefined constraints. An extensive crankshaft optimization study is performed and resulted in many novel and patented design features. A case study for a modern in-line four-cylinder crankshaft is performed to show the potentials.
Journal Article

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

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

Crankcase and Crankshaft Coupled Structural Analysis Based on Hybrid Dynamic Simulation

This paper presents the comparison of two different approaches for crankcase structural analysis. The first approach is a conventional quasi-static simulation, which will not be detailed in this work and the second approach involves determining the dynamic loading generated by the crankshaft torsional, flexural and axial vibrations on the crankcase. The accuracy of this approach consists in the development of a robust mathematical model that can couple the dynamic characteristics of the crankshaft and the crankcase, representing realistically the interaction between both components. The methodology to evaluate these dynamic responses is referred to as hybrid simulation, which consists of the solution of the dynamics of an E-MBS (Elastic Multi Body System) coupled with consecutive FEA (Finite Element Analysis).
Technical Paper

Potential of Advanced, Combined Aftertreatment Systems for Light-Duty Diesel Engines to Meet Upcoming EU and US Emission Regulation

The modern DI-diesel engine represents a valuable platform to achieve worldwide tightened CO2 standards while meeting future strengthened emission regulations in the EU and the US. Due to the simultaneous, partially contrary legal demands, new integrated and combined systems are required to allow best overall performance within the upcoming legal frames concerning pollutant emission reduction and minimization of CO2 output. As extended emission relevant areas in the engine map have to be respected in view of RDE and PEMS scenarios in EU, but also facing the LEVIII standards in the US, comprehensive and synchronized technical solutions have to be engineered. Based on furthermore optimized combustion systems with improved combustion efficiency, meaning also lowered exhaust gas temperatures, especially refined and tailored emission control systems are demanded.
Technical Paper

Lamborghini Approach to Engine Downsizing Engine Friction Modeling

Downsizing, down speeding and hybridization are becoming a standard in the automotive industry. This paper was initiated to answer Automobili Lamborghini R&D's question: what does downsizing mean In technical literature downsizing is often referred to as reducing displacement and, sometimes, cylinders. Through a methodological approach, analysis and experimental activities Automobili Lamborghini, with FEV's support, shows that downsizing in terms of engine friction reduction means only reduction of displacement. Using the Aventador V12 6.5 liter engine as a baseline, two 4.3 liter engines were designed, a V8 and a V12. The engine friction losses of these two engines were calculated all over the engine speed range and during the NEDC cycle utilizing a simulation tool and verified through FEV's “Strip-Method” database. This approach gives us the holistic understanding on engine components design and which technologies should be introduced for the next Lamborghini engine generation.