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The Szorenyi Three-Chamber Rotary Engine Concept

Partner Rotary Engine Development Agency-Peter King
Published 2019-09-09 by SAE International in United States
Currently automotive engines are reciprocating or Wankel rotary engine types. Reciprocating engines are bulky, heavy and complex, mainly due to the intake and exhaust valves and their associated cam-train. Wankel engines have a low rotor rev limit, and have inefficient sealing of the apex seals leading to poor economy and undesirable emission gases. The Rotary Engine Development Agency (REDA) has designed a new three-chamber rotary internal combustion engine concept using an adaptation of the patented Szorenyi Curve. The new design is an evolution of the design which was the subject of SAE Technical Paper 2017-01-2413 and SAE publication ‘So You Want to Design Engines: UAV Propulsion Systems’. This paper describes the features of the new three-chamber engine concept and includes an analysis of the major shortcomings of the Wankel engine. The Wankel engine’s geometry results in excessive crankshaft deflection at high engine revs due to the centrifugal force of the rotor which is eccentric to the crankshaft. This results in a low rotational speed limit. Analysis of the Wankel design reveals that the rotational speed…
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A Simple Approach for the Estimation of the Exhaust Noise Source at the Valves

CMT-Universitat Politècnica de València-Antonio J. Torregrosa, Pablo Olmeda
Renault SAS-Jean-luc Adam, Florent Morin, Maxime Dubarry
Published 2019-09-09 by SAE International in United States
Exhaust noise emission is the result of the propagation of pressure perturbations along the exhaust line, whose primary source is the instantaneous mass flow rate across the exhaust valves. In this paper, a model for the estimation of this magnitude is presented, which has two main objectives: the first one is to provide a representation of the engine as an exhaust noise source as independent as possible on the exhaust system; the second one to allow for the estimation of the exhaust mass flow in such cases where the full set of data required by a conventional gas-dynamic simulation is not available. The model presented uses a reduced set of geometrical and operation data, which can be either representative for a given engine family, or even target values for an engine still not fully defined. It is based on the estimation of in-cylinder variables at exhaust opening by means of a First-Law approach to the closed cycled, starting from rather general data on the energy balance of the engine. Then, conventional gas-dynamic equations are solved,…
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Fuel Consumption and Pollutant Emission Optimization at Part and Full Load of a High-Performance V12 SI Engine by a 1D Model

Lamborghini Automobili Spa-Diego Cacciatore, Luca Rizzi
University of Naples Federico II-Vincenzo De Bellis, Enrica Malfi, Antonio Aliperti
Published 2019-09-09 by SAE International in United States
Modern internal combustion engines show complex architectures in order to improve their performance in terms of brake torque and fuel consumption. Concerning naturally-aspirated engines, an optimization of the intake port geometry, together with the selection of a proper valve timing, allow to improve the cylinder filling and hence the performance. The identification of an optimal calibration strategy at test bench usually requires long and expensive experimental activities. Numerical tools can help to support engine calibration, especially in the early design phases.In the present work, a 12-cylinder naturally aspirated spark ignition engine is investigated. The engine is experimentally tested under full and part load operations. Main performance parameters, in-cylinder pressure cycles and raw pollutant emissions are measured. The engine is schematized in a one-dimensional model (GT-Power™), where “user routines” are employed to simulate turbulence, combustion, knock and pollutant production. 1D model is validated against the experimental data, denoting a good accuracy.A calibration procedure is implemented by an external optimizer, coupled with the 1D engine model, with the aim of minimizing the fuel consumption. The procedure decision…
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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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Hose, Polytetrafluoroethylene TFE Fluorocarbon Resin Wire Braid Reinforced

G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
  • Aerospace Material Specification
  • AMS3380E
  • Current
Published 2019-04-30 by SAE International in United States
This specification covers a polytetrafluoroethylene resin in the form of extruded and sintered flexible tube reinforced with wire braid.
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Experimental Investigations on the Influence of Valve Timing and Multi-Pulse Injection on GCAI Combustion

Indian Institute of Technology Madras-Jensen Samuel, Santhosh Mithun, Kasinath Panda, A Ramesh
MSCE, RWTH Aachen University-Maximilian Wick, Jakob Andert
Published 2019-04-02 by SAE International in United States
Gasoline Controlled Auto-Ignition (GCAI) combustion, which can be categorized under Homogeneous Charge Compression Ignition (HCCI), is a low-temperature combustion process with promising benefits such as ultra-low cylinder-out NOx emissions and reduced brake-specific fuel consumption, which are the critical parameters in any modern engine. Since this technology is based on uncontrolled auto-ignition of a premixed charge, it is very sensitive to any change in boundary conditions during engine operation. Adopting real time valve timing and fuel-injection strategies can enable improved control over GCAI combustion. This work discusses the outcome of collaborative experimental research by the partnering institutes in this direction. Experiments were performed in a single cylinder GCAI engine with variable valve timing and Gasoline Direct Injection (GDI) at constant indicated mean effective pressure (IMEP). In the first phase intake and exhaust valve timing sweeps were investigated. It was found that the Intake Valve Closing (IVC) timing and Exhaust Valve Closing (EVC) timing have a dominant influence on combustion, performance and emission parameters.In the second phase of experiments, multiple injection strategies were investigated. Here the influences…
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Valve Opening and Closing Event Finalization for Cost Effective Valve Train of Gasoline Engine

Maruti Suzuki India, Ltd.-Sanjay Poonia, Amandeep Singh, Narinder Kumar, Jaspreet Singh, Shailender Sharma
Published 2019-04-02 by SAE International in United States
With more stringent emission norm coming in future, add more pressure on IC engine to improve fuel efficiency for survival in next few decades. In gasoline SI (spark ignition) engine, valve events have major influence on fuel economy, performance and exhaust emissions. Optimization of valve event demands for extensive simulation and testing to achieve balance between conflicting requirement of low end torque, maximum power output, part load fuel consumption and emission performance. Balance between these requirements will become more critical when designing low cost valve train without VVT (Variable valve timing) to reduce overall cost of engine.Higher CR (Compression ratio) is an important low cost measure to achieve higher thermal efficiency but creates issue of knocking thereby limiting low speed high load performance. The effective CR reduction by means of late intake valve closing (LIVC) is one way to achieve higher expansion ratio while keeping high geometric CR. Due to backflow at low engine speed by late IVC (Intake valve closing) it is challenging to implement late IVC without compromising low end high load performance…
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Optimization of a Diesel Engine with Variable Exhaust Valve Phasing for Fast SCR System Warm-Up

University of Michigan-Pavan Kumar Srinivas, Rasoul Salehi
Published 2019-04-02 by SAE International in United States
Early exhaust valve opening (eEVO) increases the exhaust gas temperature by faster termination of the power stroke and is considered as a potential warm up strategy for diesel engines aftertreatment thermal management. In this study, first, it is shown that when eEVO is applied, the engine main variables such as the boost pressure, exhaust gas recirculation (EGR) and injection (timing and quantity) must be re-calibrated to develop the required torque, avoid exceeding the exhaust temperature limits and keep the air fuel ratio sufficiently high. Then, a two-step procedure is presented to optimize the engine operation after the eEVO system is introduced, using a validated diesel engine model. In the first step, the engine variables are optimized at a constant eEVO shift. In the second step, optimal eEVO trajectories are calculated using Dynamic Programming (DP) for a transient test cycle. The optimized results indicate that with early EVO, the boost pressure should be increased to provide enough cylinder air charge and to maintain the engine torque. External EGR can be reduced due to increased internal EGR…
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Effect of Exhaust Runner Length, Valve Timing and Lift on the Performance of a Gasoline Engine

University of South Australia-Saiful Bari
Published 2019-04-02 by SAE International in United States
Internal combustion (IC) engine exhaust system can influence the engine’s performance in a significant way. This paper shows that a variable exhaust manifold runner length can improve the engine performance in terms of its output torque by over 10% especially at lower engine speed. Similarly, other exhaust systems such as valve timing and valve lift can improve the performance of the engine in different magnitudes. But when smaller improvements are clubbed together, a significant improvement can be achieved. This paper researches first the exhaust runner length on the engine’s performance. Then, the exhaust valve timing is adjusted to further improve the engine torque produced for the exhaust runner lengths analyzed. Study of a combined effect showed that the runner length requirement shifts slightly as the valve timing is changed. Due to practical limitations foreseen in having longer runner lengths and limitations in the rate of runner length variation, certain areas have to undergo through a region where the torque values are as low as they can be. Though this happens in every single exhaust system…
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Modeling the Effect of Thermal Barrier Coatings on HCCI Engine Combustion Using CFD Simulations with Conjugate Heat Transfer

Auburn University-Mark Hoffman
Clemson University-Zoran Filipi
Published 2019-04-02 by SAE International in United States
Thermal barrier coatings with low conductivity and low heat capacity have been shown to improve the performance of homogeneous charge compression ignition (HCCI) engines. These coatings improve the combustion process by reducing heat transfer during the hot portion of the engine cycle without the penalty thicker coatings typically have on volumetric efficiency. Computational fluid dynamic simulations with conjugate heat transfer between the in-cylinder fluid and solid piston of a single cylinder HCCI engine with exhaust valve rebreathing are carried out to further understand the impacts of these coatings on the combustion process. For the HCCI engine studied with exhaust valve rebreathing, it is shown that simulations needed to be run for multiple engine cycles for the results to converge given how sensitive the rebreathing process is to the residual gas state. The effect of thermal barrier coatings on the piston surface is explored using the properties of Yttria-Stabilized Zirconia (YSZ) and Gadolinium Zirconate (GdZr) top coatings with two different thicknesses. Heat flux measurements from an experimental engine with an all metal piston and YSZ and…
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