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Study of the Variable Valve Timing Effects on Combustion Quality and Fuel Consumption of an Internal Combustion Engine

Mobility Technology Center – Federal University of Minas Ger-Augusto César Teixeira Malaquias, Nilton Antonio Diniz Netto, José Guilherme Coelho Baêta, Alysson Fernandes Teixeira, Sérgio Augusto Passos Costa
  • Technical Paper
  • 2019-36-0117
Published 2020-01-13 by SAE International in United States
The need for a constant evolution of internal combustion engines has encouraged the emergence of new alternatives for the minimization of pollutant emissions, fuel consumption and an increase of the overall performance. The coming years will be marked by the launch of increasingly efficient engines, given the current importance of sustainability in the means of transport. Despite the growing electrification of global mobility, research indicates that the ICE will continue to be the main source of automotive energy in the coming years and, therefore, the study of strategies aimed at optimizing its performance is and will continue to be relevant. In this sense, the purpose of this work is to study the effects of variable valve timing on the experimental calibration of an internal combustion engine intended for research. Different moments of opening and closing of both the intake and exhaust valves were analyzed so that the possible reductions in the specific fuel consumption and the combustion quality improvements could be studied in tests always aimed at maximizing the fuel conversion efficiency. The purpose was…
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Variable Camshaft Valve Timing and its Effects to Hydrous Ethanol (E100) Combustion during Engine Warm up Phase

Ford Motor Company Brazil-Gustavo C. Passarini, Marcos Fregoneze, Fernando Sarracini Júnior
  • Technical Paper
  • 2019-36-0147
Published 2020-01-13 by SAE International in United States
In-cylinder airflow has significant impact in mixture formation and burn in internal combustion engines. Exhaust valve closing retard and early intake valve opening have large contribution for the in-cylinder airflow. It may reduce pumping work (energy lost to pump exhaust gases out of the cylinder and to draw the fresh air-fuel mixture), hurt combustion stability due to the excess of residual gas in the combustion chamber or still contribute to cylinder scavenging, increasing the amount of fresh air resulting in higher burn efficiency and more work extracted from the cycle. Brazilian market has large Hydrous Ethanol fuel (E100) usage. Due to E100 fuel properties, the intake and exhaust valves opening and closing time must be carefully defined during the engine warm up phase to avoid negative effects on the combustion. The objective of this work is to analyze the effects in performance, combustion stability and emissions, of exhaust valve timing at different engine temperatures when using E100 fuel in a Ford 1.5L naturally aspirated 3-cylinder engine with Port Fuel Injection (PFI) and dual variable valve…
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Impact of Dynamic Exhaust Valve Modelling

KTH Royal Institute of Technology-Ted Holmberg, Andreas Cronhjort
Scania CV AB-Ola Stenlåås
  • Technical Paper
  • 2019-01-2346
Published 2019-12-19 by SAE International in United States
A method developed in SAE 2019-01-0058 to correct for deviations from quasi-steady exhaust valve flow is implemented on a single-cylinder GT-Power model and the effects on pumping work and blowdown pulse characteristics are investigated. The valve flow area is always reduced compared to the reference quasi-steady case. It decreases with higher pressure ratios over the valve and increases with higher engines speeds. The reduced flow area increases pumping work with load and engine speed, though primarily with engine speed. The magnitude of the blowdown pulse is reduced and the peak is shifted to a later crank angle.
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Comparison of heat losses at the impingement point and in between two impingement points in a diesel engine using phosphor thermometry

Lund University, Division of Combustion Physics-Alexios Matamis, Mattias Richter
Scania CV AB-Christian Binder, Daniel Norling
  • Technical Paper
  • 2019-01-2185
Published 2019-12-19 by SAE International in United States
In-cylinder heat losses in diesel engines reduce engine efficiency significantly and account for a considerable amount of injected fuel energy. A great part of the heat losses during diesel combustion presumably arises from the impingement of the flame. The present study compares the heat losses at the point where the flame impinges onto the piston bowl wall and the heat losses between two impingement points. Measurements were performed in a full metal heavy-duty diesel engine with a small optical access through a removed exhaust valve. The surface temperature at the impingement point of the combusting diesel spray and at a point in between two impingement points was determined using phosphor thermometry. The dynamic heat fluxes and the heat transfer coefficients which result from the surface temperature measurements are estimated. Simultaneous cylinder pressure measurements and high-speed videos are associated to individual surface temperature measurements. Thus each surface temperature measurement is linked to a specific impingement and combustion events. An analysis of the surface temperature in connection with the high speed images reveals the great impact of…
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Experimental study of cylinder oil stripping behavior at the scavenge port of a low-speed two-stroke engine

Dalian University of Technology-Min Pan, Liyan Feng, Zhen Gong, Zhengran Yu, Hongjie Sun, Zixin Wang, Peng Yan
  • Technical Paper
  • 2019-01-2335
Published 2019-12-19 by SAE International in United States
The stripping of cylinder oil at the scavenging ports of low-speed two-stroke marine engines is one of the main sources of floating oil droplets existing in cylinders. The combustion of these oil droplets is one of the major reasons of PM emissions and pre-ignition for dual-fuel engines. In order to investigate the stripping behavior, a prototype model and a test bench were set up to carry out the experiment of cylinder oil stripping behavior and single droplet deformation under different conditions. Meanwhile, a CFD model was established to analyze the actual scavenging flow field, and the verification results were obtained: in the case of excessive lubrication, a considerable amount of cylinder oil remains on the upper surface of the scavenge ports. Such cylinder oil can be blown into the cylinder when the ports are opened. Then the oil droplets floating in the cylinder or attaching to the exhaust valve form potential spontaneous combustion points, which leads to the worsening of PM emissions and the threat of pre-ignition, the most harmful abnormal combustion for Otto-cycle dual-fuel…
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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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