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Investigation of Diesel/Natural Gas RCCI Combustion Using Multiple Reaction Mechanisms at Various Engine Operating Conditions

FEV North America Inc.-Mufaddel Dahodwala, Satyum Joshi, Erik Koehler, Michael Franke, Dean Tomazic
Michigan Technological University-Jeffrey Naber
  • Technical Paper
  • 2020-01-0801
To be published on 2020-04-14 by SAE International in United States
Past experimental studies conducted by the current authors on a 13 liter 16.7:1 compression ratio heavy-duty diesel engine have shown that diesel /natural gas Reactivity Controlled Compression Ignition (RCCI) combustion targeting low NOx emissions becomes progressively difficult to control as the engine load is increased due to difficulty in controlling reactivity levels at higher loads. For the current study, CFD investigations were conducted using the SAGE combustion solver in Converge with the application of Rahimi mechanism. Studies were conducted at a load of 5 bar BMEP to validate the simulation results against RCCI test data. In the low load study, it was found that the Rahimi mechanism was not able to predict the RCCI combustion behavior for diesel injection timings advanced beyond 30bTDC. This behavior was found at multiple engine speed and load points. To resolve this, multiple reaction mechanisms were evaluated and a new reaction mechanism that combines the GRI Mech 3.0 mechanism with the Chalmers mechanism was proposed. This mechanism was found to accurately predict the ignition delay and combustion behavior with early…
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Fuel Properties and their Impact on Stochastic Pre-Ignition Occurrence and Mega Knock Severity in Turbocharged Direct Injection Engines

FEV North America Inc.-Patrick Haenel, Dean Tomazic, Henning Kleeberg, Joseph Ciaravino
  • Technical Paper
  • 2020-01-0614
To be published on 2020-04-14 by SAE International in United States
Stochastic Pre-Ignition (SPI) or Low Speed Pre-Ignition (LSPI) is an abnormal combustion event that can occur during the operation of modern, highly boosted direct-injection gasoline engines. This abnormal combustion event is characterized by an undesired and early start of combustion that is not initiated by the spark plug. Early SPI events can subsequently lead to violent auto-ignitions that are referred to as Mega- or Super-Knock in literature and have the potential to severely damage engines in the field. Numerous studies to analyze impact factors on SPI occurrence and severity have been conducted in recent years. While initial studies have focused strongly on engine oil formulation, calibration and engine design and their respective impact on SPI initiation, the impact of physical and chemical properties of the fuel have also become of interest in recent years. There is still significant uncertainty about the best way to characterize a fuels impact on SPI occurrence and severity though. We therefore performed an experimental study that attempts to link fuel characteristics to SPI event occurrence as well as assesses their…
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Trade-Off Analysis and Systematic Optimization of a Heavy-Duty Diesel Hybrid Powertrain

FEV North America Inc.-Satyum Joshi, Mufaddel Dahodwala, Erik W. Koehler, Michael Franke, Dean Tomazic
Michigan Technological University-Jeffrey Naber
  • Technical Paper
  • 2020-01-0847
To be published on 2020-04-14 by SAE International in United States
While significant progress has been made in recent years to develop hybrid and battery electric vehicles for passenger car and light-duty applications to meet future fuel economy targets, the application of hybrid powertrains to heavy-duty truck applications has been very limited. The relatively lower energy and power density of batteries in comparison to diesel fuel and the operating profiles of most heavy-duty trucks, combine to make the application of hybrid powertrain for these applications more challenging. The high torque and power requirements of heavy-duty trucks over a long operating range, the majority of which is at constant cruise point, along with a high payback period, complexity, cost, weight and range anxiety, make the hybrid and battery electric solution less attractive than a conventional powertrain. However, certain heavy-duty applications, such as Class 6-7 urban vocational trucks, can benefit from hybridization due to their transient operating profiles and relatively lower vehicle weight. While many studies have quantified the fuel consumption benefits of hybridization in this segment, very few studies have outlined the arduous process of selection and…
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NVH Aspects of Electric Drive Unit Development and Vehicle Integration

FEV Europe GmbH-Christoph Steffens, Peter Janssen
FEV North America, Inc.-Thomas Wellmann, Todd Tousignant, Kiran Govindswamy, Dean Tomazic
Published 2019-06-05 by SAE International in United States
The automotive industry continues to develop new powertrain and vehicle technologies aimed at reducing overall vehicle-level fuel consumption. Specifically, the use of electrified propulsion systems is expected to play an increasingly important role in helping OEM’s meet fleet CO2 reduction targets for 2025 and beyond. This will also include a strong growth in the global demand for electric drive units (EDUs).The change from conventional vehicles to vehicles propelled by EDUs leads to a reduction in overall vehicle exterior and interior noise levels, especially during low-speed vehicle operation. Despite the overall noise levels being low, the NVH behavior of such vehicles can be objectionable due to the presence of tonal noise coming from electric machines and geartrain components as well as relatively high shares of road/wind noise. In order to ensure customer acceptance of electrically propelled vehicles, it is imperative that these NVH challenges are understood and solved.This paper discusses various aspects of the EDU NVH development process. This will include a discussion of the NVH target cascading methodologies for EDUs, followed by a description of…
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Integration of an ORC Waste Heat Recovery with Electrification and Supercharging through Use of a Planetary Gear System for a Class 8 Tractor Application

FEV North America, Inc.-Satyum Joshi, Mufaddel Dahodwala, Erik Koehler, FNU Dhanraj, Michael Franke, Dean Tomazic
Michigan Technological Univ-Jeffrey Naber
Published 2019-04-02 by SAE International in United States
A novel approach to the Integration of Turbocompounding/WHR, Electrification and Supercharging technologies (ITES) to reduce fuel consumption in a medium heavy-duty diesel engine was previously published by FEV. This paper describes a modified approach to ITES to reduce fuel consumption on a heavy-duty diesel engine applied in a Class 8 tractor.The original implementation of the ITES incorporated a turbocompound turbine as the means for waste heat recovery. In this new approach, the turbocompound unit connected to the sun gear of the planetary gear set has been replaced by an organic Rankine cycle (ORC) turbine expander. The secondary compressor and the electric motor-generator are connected to the ring gear and the carrier gear respectively. The ITES unit is equipped with dry clutch and band brake allowing flexibility in mechanical and electrical integration of the ORC expander, secondary compressor and electric motor-generator to the engine. This approach supports electrical integration of ORC expander when the turbine power output is low and mechanical/power-split integration when the turbine power output is high. At low engine speeds and high loads,…
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Analysis of the Impact of Production Lubricant Composition and Fuel Dilution on Stochastic Pre-Ignition in Turbocharged, Direct-Injection Gasoline Engines

FEV North America Inc.-Patrick Haenel, Rob de Bruijn, Dean Tomazic, Henning Kleeberg
Published 2019-04-02 by SAE International in United States
The occurrence of abnormal combustion events leading to high peak pressures and severe knock can be considered to be one of the main challenges for modern turbocharged, direct-injected gasoline engines. These abnormal combustion events have been referred to as Stochastic Pre-Ignition (SPI) or Low-Speed Pre-Ignition (LSPI). The events are characterized by an undesired, early start of combustion of the cylinder charge which occurs before or in parallel to the intended flame kernel development from the spark plug. Early SPI events can subsequently lead to violent auto-ignitions that are often referred to as Mega- or Super-Knock. These heavy knock events lead to strong pressure oscillations which can destroy production engines within a few occurrences. SPI occurs mainly at low engine speed and high engine load, thus limiting the engine operating area that is in particular important to achieve good drivability in downsized engines. Recent experimental SPI studies have linked this phenomenon strongly to engine oils.While numerous studies have been published using target blended oils, the presented study focuses on the impact of lubricants with production level…
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Strategies for Meeting Phase 2 GHG and Ultra-Low NOx Emission Standards for Heavy-Duty Diesel Engines

SAE International Journal of Engines

FEV Inc.-Mufaddel Dahodwala, Satyum Joshi, Erik W. Koehler, Michael Franke, Dean Tomazic
  • Journal Article
  • 2018-01-1429
Published 2018-04-03 by SAE International in United States
When considered along with Phase 2 Greenhouse Gas (GHG) requirements, the proposed Air Resource Board (ARB) nitrogen oxide (NOx) emission limit of 0.02 g/bhp-hr will be very challenging to achieve as the trade-off between fuel consumption and NOx emissions is not favorable. To meet any future ultra-low NOx emission regulation, the NOx conversion efficiency during the cold start of the emission test cycles needs to be improved. In such a scenario, apart from changes in aftertreatment layout and formulation, additional heating measures will be required.In this article, a physics-based model for an advanced aftertreatment system comprising of a diesel oxidation catalyst (DOC), an SCR-catalyzed diesel particulate filter (SDPF), a stand-alone selective catalytic reduction (SCR), and an ammonia slip catalyst (ASC) was calibrated against experimental data. The calibrated model was then used to evaluate various advanced aftertreatment system configurations that included the application of an electrically heated catalyst, mini-burner, fuel dosing, passive NOx adsorber (PNA), and ammonia injection. The advanced aftertreatment system capable of meeting the 0.02 g/bhp-hr NOx emission limit with minimum fuel consumption penalty…
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Reduction of Parasitic Losses in Front-End Accessory Drive Systems: Part 2

SAE International Journal of Engines

FEV Group GmbH-Stefan Trampert
FEV North America Inc.-Marek Tatur, Dean Tomazic, Kiran Govindswamy
  • Journal Article
  • 2018-01-0326
Published 2018-04-03 by SAE International in United States
Demanding CO2 and fuel economy regulations are continuing to pressure the automotive industry into considering innovative powertrain and vehicle-level solutions. Powertrain engineers continue to minimize engine internal friction and transmission parasitic losses with the aim of reducing overall vehicle fuel consumption.In Part 1 of the study (2017-01-0893) described aspects of the test stand design that provides flexibility for adaptation to various test scenarios. The results from measurements for a number of front-end accessory drive (FEAD) components were shown in the context of scatterbands derived from multiple component tests. Key results from direct drive and belt-driven component tests were compared to illustrate the influence of the belt layout on mechanical efficiency of the FEAD system.The second part of the series will focus exclusively on the operation of the alternator. Two main elements of the study are discussed. The first part explores tests performed to evaluate the main design aspects of the component. Different belt designs, routing, and tension levels were tested and compared. A resulting matrix allows to determine an optimized belt design and layout for…
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In-Use Compliance Opportunity for Diesel Powertrains

FEV Europe GmbH-Marcel Romijn
FEV GmbH-Korfer Thomas
Published 2018-04-03 by SAE International in United States
In-use compliance under LEV III emission standards, GHG, and fuel economy targets beyond 2025 poses a great opportunity for all ICE-based propulsion systems, especially for light-duty diesel powertrain and aftertreatment enhancement. Though diesel powertrains feature excellent fuel-efficiency, robust and complete emissions controls covering any possible operational profiles and duty cycles has always been a challenge. Significant dependency on aftertreatment calibration and configuration has become a norm. With the onset of hybridization and downsizing, small steps of improvement in system stability have shown a promising avenue for enhancing fuel economy while continuously improving emissions robustness. In this paper, a study of current key technologies and associated emissions robustness will be discussed followed by engine and aftertreatment performance target derivations for LEV III compliant powertrains. The core of the discussion will be focused on identifying opportunities in engine and aftertreatment hardware and controls to position the diesel applications appropriately for future in-use compliance. Additionally, the authors will discuss the potential diesel powertrain hardware enhancements that could deliver improved emissions robustness while saving fuel, in real-world operation. Since…
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Novel Approach to Integration of Turbocompounding, Electrification and Supercharging Through Use of Planetary Gear System

FEV NA, Inc.-Satyum Joshi, Mufaddel Dahodwala, Erik W. Koehler, Michael Franke, Dean Tomazic
Michigan Technological University-Jeffrey Naber
Published 2018-04-03 by SAE International in United States
Technologies that provide potential for significant improvements in engine efficiency include, engine downsizing/downspeeding (enabled by advanced boosting systems such as an electrically driven compressor), waste heat recovery through turbocompounding or organic Rankine cycle and 48 V mild hybridization. FEV’s Integrated Turbocompounding/Waste Heat Recovery (WHR), Electrification and Supercharging (FEV-ITES) is a novel approach for integration of these technologies in a single unit. This approach provides a reduced cost, reduced space claim and an increase in engine efficiency, when compared to the independent integration of each of these technologies.This approach is enabled through the application of a planetary gear system. Specifically, a secondary compressor is connected to the ring gear, a turbocompounding turbine or organic Rankine cycle (ORC) expander is connected to the sun gear, and an electric motor/generator is connected to the carrier gear. The planetary gear system is equipped with a dry clutch and a band brake allowing flexibility in mechanical and electrical integration of the turbocompound turbine, secondary compressor and electric motor/generator to the engine. The system provides the ability to do electrical integration of…
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