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Estimation of DPF Soot Loading through Steady-State Engine Mapping and Simulation for Automotive Diesel Engines Running on Petroleum-Based Fuels

GM Powertrain-Alberto Vassallo
General Motors Global Propulsion Systems-Francesco Barba, Vincenzo Greco
Published 2017-09-04 by SAE International in United States
The aim of the present study is to improve the effectiveness of automotive diesel engine and aftertreatment calibration process through the critical evaluation of several methodologies to estimate the soot mass flow produced by diesel engines fueled by petroleum fuels and filtered by Diesel Particulate Filters (DPF). In particular, its focus has been the development of a reliable simulation method for the accurate prediction of the engine-out soot mass flow starting from Filter Smoke Number (FSN) measurements executed in steady state conditions, in order to predict the DPF loading considering different engine working conditions corresponding to NEDC and WLTP cycles.In order to achieve this goal, the study was split into two main parts:Correlation between ‘wet PM’ (measured by soot filter weighing) and the ‘dry soot’ (measured by the Micro Soot Sensor MSS). Test activities have been carried out taking into account different boundaries conditions such as calibration, driving cycle, sampling probes positions;Identification of a reliable and accurate method that allows estimating the ‘dry soot’ starting from the FSN measurements. Different equations available in literature have…
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Software Test and Calibration Using Virtual Manufacturing

GM Powertrain-William Goodwin
GM Global Propulsion Systems-Claudio Mancuso
Published 2017-03-28 by SAE International in United States
This paper describes how distributive computing along with statistical subsystem simulation can be applied to produce near production ready embedded vehicle software and calibrations. Coupling distributive computing and statistical simulation was first employed over a decade ago at General Motors to design and analyze propulsion subsystem hardware. Recently this method of simulation has been enhanced extending its capabilities to both test embedded vehicle code as well as develop calibrations. A primary advantage of this simulation technique is its ability to generate data from a statistically significant population of subsystems. The result is the acquisition of an optimal data set enabling the development of a robust design now including both embedded code and calibrations. Additionally it has been shown that there are significant economic advantages in terms of time and cost associated with this type of development when compared to traditional method. The following section will describe in detail using examples and data the advantages of this innovative approach to software testing and calibration.
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Stamped-Cover Vibro-Acoustic Optimization for Diesel Automotive Applications

GM Powertrain-Romualdo Ruotolo, Davide Donna, Giuseppe Credo, Michele Belluscio
Published 2016-06-15 by SAE International in United States
Current Diesel engines development is facing challenging vibro-acoustic requirements and at the same time is struggling with the need to reduce as much as possible the cost and the weight of the engine. The latter obviously has become a key player for fuel consumption reduction.Large covers are commonly used in the base engine design and their noise contribution to total radiated noise is not negligible. Typical covers architecture shows thick cast and ribbed plates, meaning heavy and expensive covers. An interesting option is represented by using thin stamped covers either in aluminum or in steel, that have to show a low vibrational response.The current paper focuses on the structural optimization of such a peculiar design, trying to mitigate as much as possible its noise radiation with the intent to avoid any additional acoustic enabler (e.g. wrapping by means of acoustic foams) that will increase the final cost of the component. Additionally, slots (filled with rubber element) are introduced in the thin-wall design to minimize radiated noise by limiting the panel dynamic response, still not jeopardizing…
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Prospects for Future Non-Manual Transmissions Developments for Vehicle Applications in Brazil

GM Powertrain-Rafael V. Fornari, Decio Yamada, Alexandre Suzuki
Published 2015-09-22 by SAE International in United States
The purpose of this paper is to present the origins and the technology of the different types of non-manual transmissions systems currently available and the wide potential to incorporate such technologies to the vehicles made in Brazil. The Brazilian market is experiencing a huge increase in automated and automatic transmissions vehicles share, and the OEMs are adopting different strategies to offer competitive products with affordable prices to enter in this segment. Many different alternatives are available, and there is no obvious winner. This paper will describe the concepts, the architecture and the operations of such systems and point out the pros and cons of each one.
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An Investigation of Radiation Heat Transfer in a Light-Duty Diesel Engine

SAE International Journal of Engines

GM Powertrain-Alberto Vassallo
General Motors Global R & D-Alok Warey, Vicent Domenech
  • Journal Article
  • 2015-24-2443
Published 2015-09-06 by SAE International in United States
In the last two decades engine research has been mainly focused on reducing pollutant emissions. This fact together with growing awareness about the impacts of climate change are leading to an increase in the importance of thermal efficiency over other criteria in the design of internal combustion engines (ICE). In this framework, the heat transfer to the combustion chamber walls can be considered as one of the main sources of indicated efficiency diminution. In particular, in modern direct-injection diesel engines, the radiation emission from soot particles can constitute a significant component of the efficiency losses. Thus, the main of objective of the current research was to evaluate the amount of energy lost to soot radiation relative to the input fuel chemical energy during the combustion event under several representative engine loads and speeds. Moreover, the current research characterized the impact of different engine operating conditions on radiation heat transfer. For this purpose, a combination of theoretical and experimental tools were used. In particular, soot radiation was quantified with a sensor that uses two-color thermometry along…
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Sound Power Measurement in a Semi-Reverberant, Volume Deficient Chamber

GM Powertrain-Jean Schweitzer
Michigan Technological University-Craig Reynolds, Jason Blough, Carl Anderson, Mark Johnson
Published 2015-06-15 by SAE International in United States
Sound power can be determined using a variety of methods, but precision methods require the volume of the noise source to be less than 1% of the chamber volume leading to relatively large test chambers. Automotive torque converter performance and noise testing is completed in an enclosed metallic test fixture which inhibits the use of precision methods due to volume and space limitations. This paper describes a new method developed to accurately determine sound power of an automotive torque converter in a relatively small enclosure through characterization of the test environment. The test environment was characterized using two reference noise sources designed to represent torque converter noise output and physical geometry. Sound pressure levels of the sources were measured at multiple microphone locations and at three source amplitude levels to characterize the environment. Test results were analyzed statistically to determine the microphone positions that best represent the overall sound levels in the chamber. Optimum measurement positions were found to depend on source size but independent of source amplitude. Accuracy was determined based on the variance…
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Effects of Secondary Air on the Exhaust Oxidation of Particulate Matters

SAE International Journal of Engines

GM Powertrain-Joseph Pritchard
MIT-Wai K. Cheng
  • Journal Article
  • 2015-01-0886
Published 2015-04-14 by SAE International in United States
The effects of secondary air on the exhaust oxidation of particulate matters (PM) have been assessed in a direct-injection-spark-ignition engine under fuel rich fast idle condition (1200 rpm; 2 bar NIMEP). Substantial oxidation of the unburned feed gas species (CO and HC) and significant reduction of both the particulate number (up to ∼80%) and volume (up to ∼90%) have been observed. The PM oxidation is attributed to the reactions between the PM and the radicals generated in the oxidation of the feed gas unburned species. This hypothesis is supported by the observation that the reduction in PM volume is proportional to the amount of heat release in the secondary oxidation.
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A Comprehensive Simulation Approach to Irregular Combustion

GM Powertrain-Stefan Pritze
Vienna University of Technology-Thomas Lauer, Michael Heiss, Nikola Bobicic, Werner Holly
Published 2014-04-01 by SAE International in United States
The combustion of highly boosted gasoline engines is limited by knocking combustion and pre-ignition. Therefore, a comprehensive modelling approach consisting of cycle-to-cycle simulation, reactor modelling with detailed chemistry and CFD-simulation was used to predict the knock initiation and to identify the source of pre-ignition. A 4-cylinder DISI test engine was set up and operated at low engine speeds and high boost pressures in order to verify the accuracy of the numerical approach.The investigations showed that there is a correlation between the knocking combustion and the very first combustion phase. The onset of knock was simulated with a stochastic reactor model and detailed chemistry. In parallel, measurements with an optical spark plug were carried out in order to identify the location of knock onset. The simulation results were in good agreement with the measurements.Deposits and oil/fuel-droplets are possible triggers of pre-ignition. A multi-component fuel approach was therefore introduced to predict the wall film formation with the CFD-simulation. Droplet-stripping from the wall film was evaluated. The simulation of the chemistry of the oil/fuel droplets confirmed the results…
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Estimation of Elemental Composition of Diesel Fuel Containing Biodiesel

SAE International Journal of Fuels and Lubricants

GM Powertrain-Pat Geng
General Motors-Shailesh Martin Lopes
  • Journal Article
  • 2013-01-2600
Published 2013-10-14 by SAE International in United States
Carbon, hydrogen and oxygen are major elements in vehicle fuels. Knowledge of fuels elemental composition is helpful in addressing its performance characteristics. Carbon, hydrogen and oxygen composition is an important parameter in engine calibration affecting vehicle performance, emissions and fuel economy.Biodiesel, a fuel comprised of mono-alkyl esters of long-chain fatty acids also known as Fatty Acid Methyl Esters(FAME), derived from vegetable oils or animal fats, has become an important commercial marketplace automotive fuel in the United States (US) and around the world over last few years. FAME biodiesels have many chemical and physical property differences compared to conventional petroleum based diesel fuels. Also, the properties of biodiesel vary based on the feedstock chosen for biodiesel production. One of the key differences between petroleum diesel fuels and biodiesel is the oxygen content. Typical oxygen content in pure biodiesel (B100) is about 11 weight % while conventional ultra-low sulfur petroleum diesel fuel has negligible oxygen content. High oxygen content of biodiesel impacts its characteristics compared to petroleum diesel.A previous paper (SAE2013-01-1139) discussed the change in energy content…
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Dynamic Analysis and Control System Design of Automatic Transmissions

GM Powertrain-Joel M. Maguire
General Motors LLC-Shushan Bai
  • Book
  • R-413
Published 2013-02-12 by SAE International in United States
While the basic working principle and the mechanical construction of automatic transmissions has not changed significantly, increased requirements for performance, fuel economy, and drivability, as well as the increasing number of gears has made it more challenging to design the systems that control modern automatic transmissions. New types of transmissions—continuously variable transmissions (CVT), dual clutch transmissions (DCT), and hybrid powertrains—have presented added challenges. Gear shifting in today’s automatic transmissions is a dynamic process that involves synchronized torque transfer from one clutch to another, smooth engine speed change, engine torque management, and minimization of output torque disturbance. Dynamic analysis helps to understand gear shifting mechanics and supports creation of the best design for gear shift control systems in passenger cars, trucks, buses, and commercial vehicles. Based on the authors’ graduate-level teaching material, this well-illustrated book relays how the fundamental principles of hydraulics and control systems are applied to today’s automatic transmissions. It opens with coverage of basic automatic transmission mechanics and then details dynamics and controls associated with modern automatic transmissions. Topics covered include: gear shifting…