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The Gasoline Engine in hybrid powertrains – modular approach between Cost and Efficiency optimization

AVL LIST GmbH-Wolfgang Schoeffmann, Michael Howlett, Alois Fuerhapter, Paul Kapus, Christoph Sams, Helfried Sorger
  • Technical Paper
  • 2020-01-0839
To be published on 2020-04-14 by SAE International in United States
The electrification of the powertrain is a prerequisite to meet future fuel consumption limits, while the internal combustion engine (ICE) will remain a key element of most production volume relevant powertrain concepts. High volume applications will be covered by electrified powertrains. The range will include parallel hybrids, 48V- or High voltage Mild- or Full hybrids, up to Serial hybrids. In the first configurations the ICE is the main propulsion, requiring the whole engine speed and load range including the transient operation. At serial hybrid applications the vehicle is generally electrically driven, the ICE provides power to drive the generator, either exclusively or supporting a battery charging concept. As the ICE is not mechanically coupled to the drive train, a reduction of the operation range and thus a partial simplification of the ICE is achievable. The paper shows the advances on a modular powertrain technology approach with different combinations of ICE, electrification and transmission variants, based on an engine family architecture with common parts, machining and assembly concepts, as well as the feasibility to integrate different…
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Effect of a Cylinder Deactivation Actuator with Electro-mechanical Switching System on Fuel Economy of an Automotive Engine

Motonic Corporation-Dong Hyeong Lee, Wan Jae Jeon, Jong Wung Park
University of Ulsan-Dojoong Kim
  • Technical Paper
  • 2020-01-1408
To be published on 2020-04-14 by SAE International in United States
In this paper, we present a cylinder deactivation actuator(CDA), one of the variable valve actuation mechanism, in response to strengthening CO2 and environmental regulations in major countries around the world. CDA is the most commonly used variable valve actuation system to improve the fuel efficiency and power of automotive engines, and minimizes fuel consumption by deactivating some of the cylinders during operation. Most CDA systems employ hydraulic switching systems. However, the critical problem with hydraulic switching system is that the oil temperature and pressure affect the dynamic and operating performance of the CDA system. This is a major obstacle in achieving the goal of the CDA system to improve fuel efficiency and engine performance. This paper introduces a two-step CDA mechanism equipped with an electronic switching system, which can be applied to OHC valve trains with end pivot rocker arms and can operate two valves simultaneously with a single cam. In addition, roller bearings are applied to the base cam contacts in order to fundamentally improve the wear problem which is often present in CDA…
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Dynamic Strength Co-Simulation of Valve Train Mechanism Design Virtual Validation

Maruti Suzuki India Ltd-Bhupinder Singh, Sanjay Poonia
Maruti Suzuki India, Ltd.-Ved Prakash Choudhary
  • Technical Paper
  • 2020-01-0949
To be published on 2020-04-14 by SAE International in United States
As the automotive market is very dynamic and vehicle manufactures tries to reduce the vehicle development cycle time, more focus is being given to CAE simulation technologies to reduce the design cycle time and number of physical tests. CAE engineers are continuously working on improving the accuracy of CAE simulation, such as using flexible body dynamic simulation in place of linear static analysis. Strength calculation under dynamic condition is more accurate as compared to static condition as it gives more clear understanding of stress variation with motion, contacts and mass inertia. Failure has been observed in new development of valve train pivot screw under test conditions. As per linear static analysis, design was judged OK. Normal linear static analysis is a two stage process. In 1st stage loads are calculated by hand or peak loads are taken from Multi body dynamic (MBD) rigid body analysis. In 2nd stage stress calculation is carried out for peak load in quasi static condition using Finite element analysis (FEA). To investigate the reason of failure and prediction of stress…
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Combustion Stability Improvement via Multiple Ignition Sites on a 4-cylinder Production Engine

Ford Motor Company of Canada Limited-Xiaoxi Zhang
Univ of Windsor-Jimi Tjong, Ming Zheng
  • Technical Paper
  • 2020-01-1115
To be published on 2020-04-14 by SAE International in United States
For SI engines, further improvement of engine efficiency has become the major development trend, and lean burn/EGR technologies as well as intensified in-cylinder flow need to be adapted to reach that target. Stronger ignition sources become more favorable under extreme lean/EGR conditions. Among the ignition technologies developed, multiple ignition sites technology has been proved to be an effective way to help with the initial flame kernel development. In this paper, a spark ignited 4-cylinder turbo-charged production engine is employed to investigate the impact of multiple ignition sites technology on engine performance under EGR condition. Four in-house designed 3-core sparkplugs are installed on the cylinder to generate multiple ignition sites in the cylinders. The engine is equipped with a variable valve train (VVT) system, so internal EGR can be introduced through cam timing adjustment. Under partial load, the pumping loss can be effectively reduced when internal EGR rate is increased, so the engine efficiency can be improved. However, combustion stability becomes worse in terms of higher cycle to cycle variation of the engine IMEP. Compared with…
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High Efficiency by Miller Valve Timing and Stoichiometric Combustion for a Naturally Aspirated Single Cylinder Gas Engine

Karlsruhe University of Applied Sciences-Jörn Judith, Denis Neher, Maurice Kettner
SenerTec Kraft-Wärme-Energiesysteme GmbH-Danny Schwarz, Markus Klaissle
  • Technical Paper
  • 2019-32-0588
Published 2020-01-24 by Society of Automotive Engineers of Japan in Japan
Small-scale cogeneration units (Pel < 50 kW) frequently use lean mixture and late ignition timing to comply with current NOx emission limits. Future tightened NOx limits might still be met by means of increased dilution, though both indicated and brake efficiency drop due to further retarded combustion phasing and reduced brake power. As an alternative, when changing the combustion process from lean burn to stoichiometric, a three-way-catalyst allows for a significant reduction of NOx emissions. Combustion timing can be advanced, resulting in enhanced heat release and thus increased engine efficiency.Based on this approach, this work presents the development of a stoichiometric combustion process for a small naturally aspirated single cylinder gas engine (Pel = 5.5 kW) originally operated with lean mixture. To ensure low NOx emissions, a three-way-catalyst is used. In order to achieve high engine efficiency, measures implemented include Miller valve timing, optimized intake system, reduced engine speed and increased compression ratio. In the first step, a detailed 1D engine cycle simulation model was used to investigate the efficiency benefit of Miller valve timing…
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Dynamic implicit analysis of valve train with cylinder head assembly

CAE, Product Development, Royal Enfield-Prasanth Venkatesan, T Sreenivasulu, S Karthik, Rod Giles
  • Technical Paper
  • 2019-32-0584
Published 2020-01-24 by Society of Automotive Engineers of Japan in Japan
Transient dynamic behaviour of the valve train system at constant engine speed is simulated with an implicit time integration method. The Interference fit between the valve guide, valve seat to cylinder head and preload between cam housing to cylinder head has been modelled as initial loads in the valve train. The cylinder head and cam housing have been modelled to consider the mounting stiffness on dynamics of the valve train. The temperature from steady-state CFD simulation has been mapped to the valve train, cylinder head and cam housing assembly. The expansion of the whole system has been considered, due to an increase in temperature. The cam has been rotated at specified engine speed for 360 degrees. The change in valve to guide clearance, Contact Pressure and Contact Status between valve to seat for both hot and cold condition has been compared and plotted from the simulation. Valve guide & valve seat distortion have been plotted to compare the cold and hot effects. The stress from the simulation has been used to predict the fatigue life…
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Engine Valve Train Dynamic Analysis using 1-D Simulation Approach

Tafe Motors and Tractors Limited-Ajay Nain, Devendra Nene
  • Technical Paper
  • 2019-28-2422
Published 2019-11-21 by SAE International in United States
In order to reduce engine development timing and cost, a numerical calculation used to evaluate valve train systems. This paper discusses the work done on kinematic and dynamic analysis of Valve Train (VT) system of a diesel engine by using 1-D Ricardo Valdyn software. The goal is to meet optimum intake, exhaust valve timing requirement, maximize, valve open area and 30% over-speed requirement. Valve train model is prepared and inputs like mass and stiffness are estimated from 3-D model and finite element analysis, respectively. Simulation model is used for predicting valve bounce speed, valve displacement, cam-follower contact stress and strain in the rocker arm. Initially, Kinematic analysis is carried out to study the change in valve motion characteristics such as cam contour radius, tappet contact eccentricity etc. Further to this, dynamic analysis is carried out to assess forces and stresses on valve train components. Effect of cam tappet contact stresses, buckling load on push rod, spring surge, ratio of spring force to inertia force, valve seating velocity at increased speed condition etc. are discussed in…
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Design and Development of Intake Ports for 2-Valve & 4-Valve Configurations for Heavy Duty Off-Highway Diesel Engine

College of Engineering-Sameer Tikar, Dileep Malkhede, Milankumar Nandgaonkar
Published 2019-10-11 by SAE International in United States
Future emission limits for off-highway application engines need advanced power train solutions to meet stringent emissions legislation, whilst meeting customer requirements and minimizing engineering costs. Development of diesel engines for off-highway application for different power segments need different intake port design solutions to optimise in-cylinder flow structure for efficient combustion. With adaptation of low pressure mechanical fuel injection system, intake port development becomes an important stage for reduction of emission formation at the source and improvement in fuel economy.In this paper, intake port design and development process is elaborated for two different power ratings of 75 hp and 120 hp of off-highway engine. 2-valve and 4-valve configurations are deployed for the same cylinder bore size. Considering the legislative emission limits for these two power segments of engines, intake port are designed for target swirl and flow performance within the same constraints of cylinder head bolting pattern and valve train actuation mechanism. Intake port designs are experimentally evaluated on steady state flow test rig using AVL paddle wheel method for swirl and flow coefficient performance. A…
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Development of Valve Train Configurations Optimized for Cold Start and Their Effect on Diesel Soot Emission

KIT - Karlsruhe Institute of Technology-Panagiotis Maniatis, Daniel Erforth, Uwe Wagner, Thomas Koch
Published 2019-09-09 by SAE International in United States
The continuous pursuit of more efficient diesel engines and the stricter emission regulations with the introduction of the Real Driving Emissions test (RDE) necessitate further investigations of heating strategies and their suitability in terms of series production. Under these circumstances heating strategies of a variable valve train for a single-cylinder research diesel engine have been first simulated and then experimentally tested at the Institute of Internal Combustion Engines of the Karlsruhe Institute of Technology (KIT).By combining statistical experimental design (DoE) and 1-D gas exchange simulations, empirical DoE models for the design of suitable camshaft configurations have been established. After having performed a potential assessment, the most favorable configurations were manufactured and subsequently tested. The configuration with an additional opening of an outlet valve during the intake stroke (2nd Event) shows the best compromise between engine out HC/CO emissions and an efficient exhaust gas temperature increase.The strategy-related state changes in the combustion chamber when using a 2nd Event and the resulting soot characteristics, in terms of size and distribution, resulting reactivity and filter soot number, are…
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A Global Sensitivity Analysis Approach for Engine Friction Modeling

SAE International Journal of Engines

BMW Group, Germany-Oleg Krecker, Christoph Hiltner
  • Journal Article
  • 03-12-05-0035
Published 2019-08-21 by SAE International in United States
Mechanical friction simulations offer a valuable tool in the development of internal combustion engines for the evaluation of optimization studies in terms of time efficiency. However, system modeling and evaluation of model performance may be highly complex. A high number of interacting submodels and parameters as well as a limited model transparency contribute to uncertainties in the modeling process. In particular, model calibration and validation are complicated by the unknown effect of parameters on the model output. This article presents an advanced and model-independent methodology for identifying sensitive parameters of engine friction. This allows the user to investigate an unlimited number of parameters of a model whose structure and properties are prior unknown. In contrast to widely used parameter studies, in which only one parameter is varied at a time, the use of the elementary effect method enables the consideration of interactions in the entire parameter space. Based on a sensitivity analysis (SA), the methodology offers a comprehensive and practicable approach to improve model performance and effectiveness of predictive optimization studies. The methodology is validated…
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