Use of Spark Ignition of a Central Fuel Cloud to Allow Diesel Operation with Low Cetane Fuels PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download Use of Spark Ignition of a Central Fuel Cloud to Allow Diesel Operation with Low Cetane Fuels PDF full book. Access full book title Use of Spark Ignition of a Central Fuel Cloud to Allow Diesel Operation with Low Cetane Fuels by David Robert Stevenson. Download full books in PDF and EPUB format.
Author: David Robert Stevenson
Publisher:
ISBN:
Category :
Languages : en
Pages : 226
Get Book Here
Book Description
Author: David Robert Stevenson
Publisher:
ISBN:
Category :
Languages : en
Pages : 226
Get Book Here
Book Description
Author: Bernard F. Enright
Publisher:
ISBN:
Category :
Languages : en
Pages : 244
Get Book Here
Book Description
Author: Yuh-Yih Wu
Publisher:
ISBN:
Category :
Languages : en
Pages : 236
Get Book Here
Book Description
Author: Aravindh Babu Viswanathan
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Get Book Here
Book Description
Interest in utilizing low-cetane fuels in heavy-duty compression ignition (CI) engines is on the rise to take advantage of fuel availability trends and improve urban air quality. This comes from the need to continue taking advantage of the superior efficiency of the mixing-controlled combustion mode used in CI engines while transitioning away from their current fuel of choice, diesel, toward cleaner low-cetane fuels. A thorough understanding of the challenges that could arise during mixing-controlled combustion of low-cetane fuels is needed to successfully navigate this transition. This research surveys the existing literature, enumerates the chief challenges to such a transition, proposes a novel approach with the potential to mitigate those challenges and conducts studies to study the viability of the technology and its potential to improve products on the field. One of the major challenges that is expected to arise during mixing-controlled combustion of low-cetane fuels is the difference in autoignition propensities between diesel (very high) and low-cetane fuels (typically low). Analysis of the literature pertaining to the use of gasoline in CI engines (referred to as GCI) is expected to offer extensive guidance to the present study of low-cetane fuels and identify areas that need addressing. Thus, a detailed survey of the current state of GCI research is presented in this report to enumerate the most significant challenges that are faced during mixing-controlled combustion of low-cetane fuels. The survey leads to the conclusion that stable combustion at low loads and the ability to operate the engine within emission limits under cold engine conditions will pose the most significant hurdles to a transition away from diesel. Reduced cylinder operation is identified as a technology with the potential to mitigate these challenges while also being a sufficiently developed technology to offer a realistic pathway to OEM implementation. Since RCO has never been studied as a combustion stabilization technology, experiments were carried out to assess the viability of cylinder deactivation in this novel role, by comparing the combustion stabilities of GCI operation when different sets of cylinders were deactivated. These experiments demonstrate that even at no-load conditions, cylinder deactivation enables stable GCI combustion while offering significant thermal and fuel efficiency benefits. Building on these results, experiments are conducted to compare RCO against intake pressurization, the chief alternative being proposed to stabilize GCI combustion. The intake pressurization is achieved by using another highly developed technology: 48V mild hybridization. Two electrically assisted air handling topologies are considered and compared against RCO from stabilization as well as performance standpoints. The results show RCO to have a clear advantage when considering aftertreatment performance, although the mild-hybrid components provide more robust stabilization. Combined optimization shows that these advantages can be combined with careful optimization. RCO is shown to alter several boundary conditions simultaneously and a 3-D CFD study is carried out to isolate the respective roles of each in combustion stabilization. In addition to significant roles for the pressure and temperature at intake valve closing, the combustion dwell (between the end of the injection event and the start of combustion) is seen to have an unexpectedly significant role in the combustion efficiency and stability. A subset of simple RCO strategies is then implemented on a heavy-duty engine and steady-state and transient experiments are conducted. These experiments show substantial benefits to implementing even simple RCO strategies on a heavy-duty engine, including faster aftertreatment warmup and slower aftertreatment cooldown as well as stability and fuel consumption benefits. Subsequently, simulations are conducted to assess the value of the remaining RCO strategies to GCI and even more substantial fuel consumption, aftertreatment thermal management and emissions benefits are predicted.
Author: Han-ying Wang
Publisher:
ISBN:
Category :
Languages : en
Pages : 206
Get Book Here
Book Description
Author: Duane L. Abata
Publisher:
ISBN:
Category : Diesel motor
Languages : en
Pages : 22
Get Book Here
Book Description
Author: Nathaniel Bryce Oliver
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
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.
Author: Bradlee J. Stroia
Publisher:
ISBN:
Category : Diesel motor
Languages : en
Pages : 16
Get Book Here
Book Description
Author: Thermo Power Corporation. Tecogen Division
Publisher:
ISBN:
Category : Diesel motor
Languages : en
Pages : 146
Get Book Here
Book Description
Author: Bradlee J. Stroia
Publisher:
ISBN:
Category :
Languages : en
Pages : 366
Get Book Here
Book Description
