Refine Your Search

Topic

Author

Affiliation

Search Results

Technical Paper

360° vs. 270° vs. 180°: The Difference of Balancing a 2 Cylinder Inline Engine: Design, Simulation, Comparative Measurements

2012-10-23
2012-32-0106
Beside the automotive industry, where 2-cylinder inline engines are catching attention again, twin-cylinder configurations are quite usual in the small engine world. From stationary engines and range-extender use to small motorcycles up to big cruisers and K-Cars this engine architecture is used in many types of applications. Because of very good overall packaging, performance characteristics and not least the possibility of parts-commonality with 4-cylinder engines nearly every motorcycle manufacturer provides an inline twin in its model range. Especially for motorcycle applications where generally the engine is a rigid member of the frame and vibrations can be transferred directly to the rider an appropriate balancing system is required.
Technical Paper

A 3D Linear Acoustic Network Representation of Mufflers with Perforated Elements and Sound Absorptive Material

2017-06-05
2017-01-1789
The acoustics of automotive intake and exhaust systems is typically modeled using linear acoustics or gas-dynamics simulation. These approaches are preferred during basic sound design in the early development stages due to their computational efficiency compared to complex 3D CFD and FEM solutions. The linear acoustic method reduces the component being modelled to an equivalent acoustic two-port transfer matrix which describes the acoustic characteristic of the muffler. Recently this method was used to create more detailed and more accurate models based on a network of 3D cells. As the typical automotive muffler includes perforated elements and sound absorptive material, this paper demonstrates the extension of the 3D linear acoustic network description of a muffler to include the aforementioned elements. The proposed method was then validated against experimental results from muffler systems with perforated elements and sound absorptive material.
Technical Paper

A Comprehensive Study on Different System Level Engine Simulation Models

2013-04-08
2013-01-1116
Engine simulation can be performed using model approaches of different depths in capturing physical effects. The present paper presents a comprehensive comparison study on seven different engine models. The models range from transient 1D cycle resolved approaches to steady-state non-dimensional maps. The models are discussed in the light of key features, amount and kind of required input data, model calibration effort and predictability and application areas. The computational performance of the different models and their capabilities to capture different transient effects is investigated together with a vehicle model under real-life driving conditions. In the trade-off field of model predictability and computational performance an innovative approach on crank-angle resolved cylinder modeling turned out to be most beneficial.
Technical Paper

A Computational Study on the Impact of Cycle-to-Cycle Combustion Fluctuations on Fuel Consumption and Knock in Steady-State and Drivecycle Operation

2013-09-08
2013-24-0030
In spark-ignition engines, fluctuations of the in-cylinder pressure trace and the apparent rate of heat release are usually observed from one cycle to another. These Cycle-to-Cycle Variations (CCV) are affected by the early flame development and the subsequent flame front propagation. The CCV are responsible for engine performance (e.g. fuel consumption) and the knock behavior. The occurrence of the phenomena is unpredictable and the stochastic nature offers challenges in the optimization of engine control strategies. In the present work, CCV are analyzed in terms of their impact on the engine knock behavior and the related efficiency. Target is to estimate the possible fuel consumption savings in steady-state operation and in the drivecycle, when CCV are reduced. Since CCV are immanent on real engines, such a study can only be done by means of simulation.
Technical Paper

A Correlation Methodology between AVL Mean Value Engine Model and Measurements with Concept Analysis of Mean Value Representation for Engine Transient Tests

2017-09-04
2017-24-0053
The use of state of the art simulation tools for effective front-loading of the calibration process is essential to support the additional efforts required by the new Real Driving Emission (RDE) legislation. The process needs a critical model validation where the correlation in dynamic conditions is used as a preliminary insight into the bounds of the representation domain of engine mean values. This paper focuses on the methodologies for correlating dynamic simulations with emissions data measured during dynamic vehicle operation (fundamental engine parameters and gaseous emissions) obtained using dedicated instrumentation on a diesel vehicle, with a particular attention for oxides of nitrogen NOx specie. This correlation is performed using simulated tests run within AVL’s mean value engine and engine aftertreatment (EAS) model MoBEO (Model Based Engine Optimization).
Technical Paper

A Cross Domain Co-Simulation Platform for the Efficient Analysis of Mechatronic Systems

2010-04-12
2010-01-0239
Efficient integration of mechanics and microelectronics components is nowadays a must within the automotive industry in order to minimize integration risks and support optimization of the entire system. We propose in this work a cross domain co-simulation platform for the efficient analysis of mechatronic systems. The interfacing of two state-of-the-art simulation platforms provides a direct link between the two domains at an early development stage, thus enabling the validation and optimization of the system already during modeling phase. The proposed cross-domain co-simulation is used within our TEODACS project for the analysis of the FlexRay technology. We illustrate using a drive-by-wire use case how the different architecture choices may influence the system.
Journal Article

A Hybrid Development Process for NVH Optimization and Sound Engineering Considering the Future Pass-by Homologation Demands

2016-11-08
2016-32-0043
Beside hard facts as performance, emissions and fuel consumption especially the brand specific attributes such as styling and sound are very emotional, unique selling prepositions. To develop these emotional characters, within the given boundary conditions of the future pass-by regulation, it is necessary to define them at the very beginning of the project and to follow a consequent development process. The following paper shows examples of motorcycle NVH development work on noise cleaning and sound engineering using a hybrid development process combining front loading, simulation and testing. One of the discussed solutions is the investigation of a piston pin offset in combination with a crankshaft offset for the reduction of friction. The optimization of piston slap noise as a result of the piston secondary motion was performed by simulation. As another example a simulation based development was performed for the exhaust system layout.
Journal Article

A Miniature Catalytic Stripper for Particles Less Than 23 Nanometers

2013-04-08
2013-01-1570
The European Emissions Stage 5b standard for diesel passenger cars regulates particulate matter to 0.0045 g/km and non-volatile part/km greater than 23 nm size to 6.0x10₁₁ as determined by the PMP procedure that uses a heated evaporation tube to remove semi-volatile material. Measurement artifacts associated with the evaporation tube technique prevents reliable extension of the method to a lower size range. Catalytic stripper (CS) technology removes possible sources of these artifacts by effectively removing all hydrocarbons and sulfuric acid in the gas phase in order to avoid any chemical reactions or re-nucleation that may cause measurement complications. The performance of a miniature CS was evaluated and experimental results showed solid particle penetration was 50% at 10.5 nm. The sulfate storage capacity integrated into the CS enabled it to chemically remove sulfuric acid vapor rather than rely on dilution to prevent nucleation.
Technical Paper

A Model-Based Analysis on Size Distribution and Rate of Evaporation for Fuel Drops in a Gasoline Spray in the Engine

2012-04-16
2012-01-1264
Good understanding of fuel sprays in the engine cylinder is crucial to optimizing the operation of direct injection gasoline engines. In this paper, a detailed analysis is conducted on direct gasoline injection sprays from a multi-hole injector. Penetrations and angles of the sprays are characterized with a homogeneous model for the fuel spray. The drop size distributions in the sprays are analyzed using an empirical distribution model. Predicted spray penetrations, spray angles, and drop size distributions under three different injection pressures are compared with the measurements for injection pressures = 40, 100 and 150 bar and good agreements are observed. Transient evaporation rates are also studied for fuel drops in an environment simulating the cylinder condition during the intake stroke of a direct injection gasoline engine.
Technical Paper

A Rankine Cycle System for Recovering Waste Heat from HD Diesel Engines - Experimental Results

2011-04-12
2011-01-1337
A Rankine cycle system with ethanol as the working fluid was developed to investigate the fuel economy benefit of recovering waste heat from a 10.8-liter heavy-duty (HD) truck diesel engine. Recovering rejected heat from a primary engine with a secondary bottoming cycle is a proven concept for improving the overall efficiency of the thermodynamic process. However, the application of waste heat recovery (WHR) technology to the HD diesel engine has proven to be challenging due to cost, complexity, packaging and control during transient operation. This paper discusses the methods and technical innovations required to achieve reliable high performance operation of the WHR system. The control techniques for maintaining optimum energy recovery while protecting the system components and working fluid are described. The experimental results are presented and demonstrate that 3-5% fuel saving is achievable by utilizing this technology.
Technical Paper

A Rankine Cycle System for Recovering Waste Heat from HD Diesel Engines - WHR System Development

2011-04-12
2011-01-0311
Waste heat recovery (WHR) has been recognized as a promising technology to achieve the fuel economy and green house gas reduction goals for future heavy-duty (HD) truck diesel engines. A Rankine cycle system with ethanol as the working fluid was developed at AVL Powertrain Engineering, Inc. to investigate the fuel economy benefit from recovering waste heat from a 10.8L HD truck diesel engine. Thermodynamic analysis on this WHR system demonstrated that 5% fuel saving could be achievable. The fuel economy benefit can be further improved by optimizing the design of the WHR system components and through better utilization of the available engine waste heat. Although the WHR system was designed for a stand-alone system for the laboratory testing, all the heat exchangers were sized such that their heat transfer areas are equivalent to compact heat exchangers suitable for installation on a HD truck diesel engine.
Technical Paper

A Scalable Simulation Method for the Assessment of Cycle-to-Cycle Combustion Variations and their impact on Fuel Consumption and Knock

2015-01-14
2015-26-0213
In the present work, a scalable simulation methodology is presented that enables the assessment of the impact of SI-engine cycle-to-cycle combustion variations on fuel consumption and hence CO2 emissions on three different levels of modeling depth: in-cylinder, steady-state engine and transient engine and vehicle simulation. On the detailed engine combustion chamber level, a 3D-CFD approach is used to study the impact of the turbulent in-cylinder flow on the cycle-resolved flame propagation characteristics. On engine level, cycle-to-cycle combustion variations are assessed regarding their impact on indicated mean effective pressure, aiming at estimating the possible fuel consumption savings when cyclic variations are minimized. Finally, on the vehicle system level, a combined real-time engine approach with crank-angle resolved cylinder is used to assess the potential fuel consumption savings for different vehicle drivecycle conditions.
Journal Article

A Semi-Empirical Model for Predicting Pressure Drops of Fouled EGR Coolers

2010-10-05
2010-01-1948
The performance of an EGR cooler is influenced significantly by particulate fouling in the cooler. As a result of fouling, a highly porous soot deposit layer is formed in the EGR cooler. This deposit layer not only causes a decrease in the cooler effectiveness but also an increase in the EGR pressure drop over the cooler. Increasing the EGR cooler pressure drop reduces the driving force for the EGR flow under a given differential pressure across the engine. Thus, the EGR cooler fouling has a big impact on the control of the engine-out NO emissions. In this paper, a semi-empirical model is developed for predicting pressure drops of fouled EGR coolers. Based on this model and the particulate fouling model developed previously by the author, the process is analyzed for the pressure drop increase with building up of the soot deposit in an EGR cooler.
Technical Paper

A Simulation Approach for Vehicle Life-Time Thermal Analysis Applied to a HEV Battery System

2016-04-05
2016-01-0201
In order to meet current and future emission and CO2 targets, an efficient vehicle thermal management system is one of the key factors in conventional as well as in electrified powertrains. Global vehicle simulation is already a well-established tool to support the vehicle development process. In contrast to conventional vehicles, electrified powertrains offer an additional challenge to the thermal conditioning: the durability of E-components is not only influenced by temperature peaks but also by the duration and amplitude of temperature swings as well as temperature gradients within the components during their lifetime. Keeping all components always at the preferred lowest temperature level to avoid ageing under any conditions (driving, parking, etc.) will result in very high energy consumption which is in contradiction to the efficiency targets.
Technical Paper

A Software Tool for Noise Quality and Brand Sound Development

2001-04-30
2001-01-1573
For noise quality and brand sound design of passenger cars a unique software tool is currently used by our clients world-wide to evaluate and optimise the interior noise quality and brand sound aspects of passenger cars on an objective basis. The software tools AVL-VOICE and AVL-COMFORT are designed for the objective analysis of interior noise quality, for benchmarking, for the definition of noise quality targets and most important for effective vehicle sound engineering. With this tool, the target orientated implementation of the required interior noise quality or brand sound by predictable hardware modifications into passenger cars - for tailor made joy of driving - becomes feasible. The use of this tools is drastically reducing vehicle evaluation time and sound engineering effort when compared with traditional jury subjective evaluation methods and standard acoustic NVH optimisation procedures.
Journal Article

A Thermodynamic Model for a Single Cylinder Engine with Its Intake/Exhaust Systems Simulating a Turbo-Charged V8 Diesel Engine

2011-04-12
2011-01-1149
In this paper, a thermodynamic model is discussed for a single cylinder diesel engine with its intake and exhaust systems simulating a turbo-charged V8 diesel engine. Following criteria are used in determination of the gas exchange systems of the single cylinder engine (SCE): 1) the level of pressure fluctuations in the intake and exhaust systems should be within the lower and upper bounds of those simulated by the thermodynamic model for the V8 engine and patterns of the pressure waves should be similar; 2) the intake and exhaust flows should be reasonably close to those of the V8 engine; 3) the cylinder pressures during the combustion and gas exchange should be reasonably close to those of the V8 engine under the same conditions for the valve timing, fuel injection, rate of heat release and in-cylinder heat transfer. The thermodynamic model for the SCE is developed using the 1D engine thermodynamic simulation tool AVL BOOST.
Technical Paper

A Versatile Approach for an ISO26262 Compliant Hardware-Software Interface Definition with Model-Based Development

2015-04-14
2015-01-0148
Increasing demands for safety, security, and certifiability of embedded automotive systems require additional development effort to generate the required evidences that the developed system can be trusted for the application and environment it is intended for. Safety standards such as ISO 26262 for road vehicles have been established to provide guidance during the development of safety-critical systems. The challenge in this context is to provide evidence of consistency, correctness, and completeness of system specifications over different work-products. One of these required work-products is the hardware-software interface (HSI) definition. This work-product is especially important since it defines the interfaces between different technologies. Model-based development (MBD) is a promising approach to support the description of the system under development in a more structured way, thus improving resulting consistency.
Journal Article

A ‘Microscopic’ Structural Mechanics FE Model of a Lithium-Ion Pouch Cell for Quasi-Static Load Cases

2013-04-08
2013-01-1519
This study deals with the experimental investigation of the mechanical properties of a lithium-ion pouch cell and its modelling in an explicit finite element simulation code. One can distinguish between ‘macroscopic’ and ‘microscopic’ modelling approaches. In the ‘macroscopic’ approach, one material model approximates the behaviour of multiple inner cell layers. In the ‘microscopic’ approach, which is used in the present study, all layers and their interactions are modelled separately. The cell under study is a pouch-type lithium-ion cell with a liquid electrolyte. With its cell chemistry, design, size and capacity it is usable for automotive applications and can be assembled into traction batteries. One cell sample was fully discharged and disassembled, and its components (anode, cathode, separator and pouch) were examined and measured by electron microscopy. Components were also tensile tested.
Technical Paper

Achieving Compliance to RDE - How Does This Development Target Impact the Development Process, Testing Methodologies and Tools

2019-01-09
2019-26-0358
At first glance RDE seems to be a road testing topic only, mistakenly. While Type approval test must be performed at the Road and Chassis Dyno, development work beforehand delivers solutions fulfilling the demanded legislation limits. Making the right development steps and decisions will lead to a technical solution within economy of scales. Much of this work done happens on engine testbeds and Real Driving Emissions (RDE) per UN-ECE legislation or the new test cycle for the chassis dyno according WLTP (Worldwide Harmonized Light-Duty Test Procedure) will not change that. The question is, are engine test beds fit for this new challenge or are changes required? One characteristic element of RDE is the randomness of operating conditions generated by a road drive. There must be found a way, to achieve RDE relevant test conditions in a most reproducible manner.
Technical Paper

Active Path Tracking - A Rapid Method for the Identification of Structure Borne Noise Paths in Vehicle Chassis

2001-04-30
2001-01-1470
The effective identification and control of powertrain structure borne harmonic noise is one key for achieving the desired noise pattern in a vehicle. Much work is being done in this field to refine and develop transfer path analysis techniques suitable for application at each stage of a vehicle development program. For vehicle application, transfer path analysis and source identification techniques are in use today with varying degrees of success and application complexity. Investigation tools which are fast, do not require extensive vehicle dismantling and yet provide reliable answers, are of great value to NVH and sound quality engineers. A novel Active Path Tracking (APT) method has been developed which is fast to apply and offers immediate practical confirmation of the contributions of all identified chassis transmission paths to the vehicle interior.
X