Author: Sang-Suk LeePublisher:
ISBN:
Category :
Languages : en
Pages : 256
Book Description
Investigation of Two Low Emissions Strategies for Diesel Engines
Investigations of Advanced Injection and Combustion Strategies in Low-emissions Diesel Engines
Author: Sage L. KokjohnImplementation and Control of Stoichiometric Natural Gas Combustion to Enable Low-emission Diesel Engines
Author: Nathaniel Bryce OliverPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The expected growth in the heavy-duty transportation sector necessitates the development of engine technologies able to increase efficiency and reduce emissions without sacrificing power output. Previous research has demonstrated that reducing heat transfer losses from the cylinder can enable significant efficiency gains in Diesel engines. The high in-cylinder temperatures generated in this engine architecture enable the use of low-cetane fuels with the potential for low-soot operation. Low soot emissions allow the equivalence ratio to be increased to stoichiometric which increases power, and could allow the existing Diesel aftertreatment system to be replaced with a less-expensive three-way catalyst. Natural gas is a promising candidate for stoichiometric, high-temperature, Diesel-style combustion. Its high hydrogen-to-carbon ratio should be able to reduce both soot and carbon dioxide emissions, and its wide distribution as a commercial and residential fuel provides existing infrastructure to speed deployment in transportation applications. This thesis demonstrates stoichiometric, Diesel-style combustion of neat methane as a single-component surrogate for natural gas. It explores the challenges of injecting a gaseous fuel at high pressures, and demonstrates the fuel's capacity for low emissions. It then provides a preliminary investigation into multiple-injection strategies for controlling combustion behavior and emissions in a stoichiometric, high-temperature engine architecture. First, fuel system hardware is developed to enable gaseous operation and preliminary experimentation is accomplished with methane. A fuel compression system is designed to supply methane at pressures suitably high to achieve good mixing and short injection durations, and a solenoid-actuated Diesel fuel injector is modeled and modified to inject methane at these pressures. This fuel injection system is then implemented on a single-cylinder engine. An insulated piston face, air cooled head, and intake preheating achieve suitable start of injection temperatures to ignite methane. Intake preheating is varied at low equivalence ratios to determine the sensitivity of engine performance to temperature at the lowest-load, lowest-temperature conditions of interest. A sweep of equivalence ratio demonstrates soot emissions roughly four times the current EPA limit for heavy-duty vehicles and combustion efficiencies of approximately 92% at stoichiometric fuel loading. High soot levels and low combustion efficiencies are also seen at the lowest equivalence ratios investigated. This suggests poorly mixed combustion, and poor injector performance. Second, injector dynamics are examined in greater detailed, and emissions performance is characterized with improved injector performance. High-speed Schlieren imaging is able to determine the injection dynamics contributing to high low-load emissions. A parametric modeling investigation suggests that reducing the injector plunger length is able to remove flow rate oscillations seen at long injection durations, and that the addition of dry friction is able to reduce the magnitude of low-momentum post injections occurring after injector closing. Dry friction is implemented using PTFE O-rings installed between the injector body and plunger. Imaging is used to confirm that a shortened plunger is able to remove long-duration oscillations, and to determine the number of O-rings necessary to suitably reduce post injection magnitude. The improved injector is used to repeat the sweep of equivalence ratios and demonstrates improved soot emissions at all operating conditions. Most notably, low-load soot emissions are reduced by more than a factor of ten, demonstrating the effectiveness of improved injector performance for improving emissions. Techniques for further improving injector performance and potential changes to injector design are discussed. Finally, the prospects for controlling combustion in a stoichiometric, low heat rejection Diesel engine using multiple injections are discussed and experimentally investigated. The applications and effects of multiple injection strategies in traditional Diesel engines are explored, and their potential extension to stoichiometric engines is discussed. Methanol engine operation enables the use of a fast-actuating piezoinjector and the realization of short injection pulses. A range of two-injection strategies are implemented in order to determine the sensitivity of engine operation to pilot, split-main, and post-injection timing and duration. Small pilot injections are found to have control authority over rate of pressure rise and peak pressure and show some promise for improving combustion efficiency. Post injections demonstrate authority over peak pressure and combustion efficiency. All of these effects are accomplished with minimal impact on engine work output. The experiments of this thesis demonstrate that, even with course control of injection, high-temperature, stoichiometric combustion of methane is able to greatly reduce soot emissions over traditional Diesel engines. Improved injector dynamics and the implementation of multiple injection strategies further improve emissions and combustion performance, suggesting substantial room for refinement of the technology and motivating the continued development of injector hardware and injection strategies. The ability to operate a Diesel engine at stoichiometric fueled only by natural gas and to employ a three-way catalyst for emissions abatement makes this strategy a clean, efficient, high-torque, and low-cost solution for heavy-duty transportation.
An Experimental Investigation of Advanced Diesel Combustion Strategies for Emissions Reductions in a Heavy-duty Diesel Engine at High Speed and Medium Load
Author: William L. HardyNatural Gas Engines
Author: Kalyan Kumar SrinivasanPublisher: Springer
ISBN: 9811333076
Category : Technology & Engineering
Languages : en
Pages : 428
Book Description
This book covers the various advanced reciprocating combustion engine technologies that utilize natural gas and alternative fuels for transportation and power generation applications. It is divided into three major sections consisting of both fundamental and applied technologies to identify (but not limited to) clean, high-efficiency opportunities with natural gas fueling that have been developed through experimental protocols, numerical and high-performance computational simulations, and zero-dimensional, multizone combustion simulations. Particular emphasis is placed on statutes to monitor fine particulate emissions from tailpipe of engines operating on natural gas and alternative fuels.
Investigation of the Performance and Emissions Characteristics of Dual Fuel Combustion in a Single Cylinder IDI Diesel Engine
Author: Johnnie L. Williams (Jr.)Publisher:
ISBN:
Category : Diesel motor exhaust gas
Languages : en
Pages : 136
Book Description
Author's Abstract: Restrictions in the allowable exhaust gas emissions of diesel engines has become a driving factor in the design, development, and implementation of internal combustion (IC) engines. A dual fuel research engine concept was developed and implemented in an indirect injected engine in order to research combustion characteristics and emissions for non-road applications. The experimental engine was operated at a constant speed and load 2400 rpm and 5.5 bar indicated mean effective pressure (IMEP). n-Butanol was port fuel injected at 10%, 20%, 30%, and 40% by mass fraction with neat ultra-low sulfur diesel (ULSD#2). Peak pressure, maximum pressure rise rates, and heat release rates all increased with the increasing concentration of n-Butanol. MPRR increased by 127% and AHRR increased by 30.5% as a result of the shorter ignition delay and combustion duration. Ignition delay and combustion duration were reduced by 3.6% and 31.6% respectively. This occurred despite the lower cetane number of n-Butanol as a result of increased mixing due to the port fuel injection of the alcohol. NOx and soot were simultaneously reduced by 21% and 80% respectively. Carbon monoxide and unburned hydrocarbons emissions were increased for the dual fuel combustion strategies due to valve overlap. Results display large emission reductions of harmful pollutants, such as NOx and soot.
Diesel Combustion and Emissions
Author: Society of Automotive EngineersPublisher:
ISBN:
Category : Air
Languages : en
Pages : 154
Book Description
A Theoretical and Experimental Study of Emissions Modeling for Diesel Engines with Comparisons to In-cylinder Imaging
Author: Gregory James HampsonPublisher:
ISBN:
Category :
Languages : en
Pages : 674
Book Description
An Experimental Investigation of Dual-injection Strategies on Diesel-methane Dual-fuel Low Temperature Combustion in a Single Cylinder Research Engine
Author: Aamir SohailPublisher:
ISBN:
Category :
Languages : en
Pages : 84
Book Description
The present manuscript discusses the performance and emission benefits due to two diesel injections in diesel-ignited methane dual fuel Low Temperature Combustion (LTC). A Single Cylinder Research Engine (SCRE) adapted for diesel-ignited methane dual fuelling was operated at 1500 rev/min and 5 bar BMEP with 1.5 bar intake manifold pressure. The first injection was fixed at 310 CAD. A 2nd injection sweep timing was performed to determine the best 2nd injection timing (as 375 CAD) at a fixed Percentage Energy Substitution (PES 75%). The motivation to use a second late injection ATDC was to oxidize Unburnt Hydrocarbons (HC) generated from the dual fuel combustion of first injection. Finally, an injection pressure sweep (550-1300 bar) helped achieve simultaneous reduction of HC (56%) and CO (43%) emissions accompanied with increased IFCE (10%) and combustion efficiency (12%) w.r.t. the baseline single injection (at 310 CAD) of dual fuel LTC.
Cost, Effectiveness, and Deployment of Fuel Economy Technologies for Light-Duty Vehicles
Author: National Research CouncilPublisher: National Academies Press
ISBN: 0309373913
Category : Science
Languages : en
Pages : 812
Book Description
The light-duty vehicle fleet is expected to undergo substantial technological changes over the next several decades. New powertrain designs, alternative fuels, advanced materials and significant changes to the vehicle body are being driven by increasingly stringent fuel economy and greenhouse gas emission standards. By the end of the next decade, cars and light-duty trucks will be more fuel efficient, weigh less, emit less air pollutants, have more safety features, and will be more expensive to purchase relative to current vehicles. Though the gasoline-powered spark ignition engine will continue to be the dominant powertrain configuration even through 2030, such vehicles will be equipped with advanced technologies, materials, electronics and controls, and aerodynamics. And by 2030, the deployment of alternative methods to propel and fuel vehicles and alternative modes of transportation, including autonomous vehicles, will be well underway. What are these new technologies - how will they work, and will some technologies be more effective than others? Written to inform The United States Department of Transportation's National Highway Traffic Safety Administration (NHTSA) and Environmental Protection Agency (EPA) Corporate Average Fuel Economy (CAFE) and greenhouse gas (GHG) emission standards, this new report from the National Research Council is a technical evaluation of costs, benefits, and implementation issues of fuel reduction technologies for next-generation light-duty vehicles. Cost, Effectiveness, and Deployment of Fuel Economy Technologies for Light-Duty Vehicles estimates the cost, potential efficiency improvements, and barriers to commercial deployment of technologies that might be employed from 2020 to 2030. This report describes these promising technologies and makes recommendations for their inclusion on the list of technologies applicable for the 2017-2025 CAFE standards.