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Viewing 151 to 180 of 22823
2015-04-14
Technical Paper
2015-01-1070
Hanzhengnan Yu, Yong Guo, Donghai Li, Xingyu Liang, Ge-Qun Shu, Yuesen Wang, Xiangxiang Wang, Lihui Dong
Abstract Impingement of injected fuel spray against the cylinder liner (wall wetting) is one of the main obstacles that must be overcome in order for early injection Homogeneous Charge Compression Ignition (EI HCCI) combustion. In the strategies to reduce or prevent wall wetting explored in the past, limiting the spray cone angle was proved to be a useful approach. This paper is presented to study the effect of the spray cone angle on the mixture formation, particularly the region near the cylinder wall (wall wetting region), and CO/Soot emissions of an EI HCCI diesel engine. Three-dimensional modeling was performed in AVL FIRE code. The calculation grid was divided into three regions which were defined as the combustion chamber region, the wall wetting region, and the central regions. The history of the CO/soot mass of each region and the equivalent ratio/temperature (φ-T map) of wall wetting region were analyzed.
2015-04-14
Technical Paper
2015-01-1055
Apoorv Kalyankar, Achuth Munnannur, Z. Gerald Liu
Abstract Selective catalytic reduction (SCR) is a promising technology for meeting the stringent requirements pertaining to NOx emissions. One of the most important requirements to achieve high DeNOx performance is to have a high uniformity of ammonia to NOx ratio (ANR) at the SCR catalyst inlet. Steady state 3D computational fluid dynamics (CFD) models are frequently used for predicting ANR spatial distribution but are not feasible for running a transient cycle like Federal Test Procedure (FTP). On the other hand, 1D kinetic models run in real time and can predict transient SCR performance but do not typically capture the effect of non-axial non-uniformities. In this work, two 3D to 1D coupling methods have been developed to predict transient SCR system performance, taking the effect of ANR non-uniformity into account. First is a probability density function (PDF) based approach and the second is a geometrical sector based approach.
2015-04-14
Technical Paper
2015-01-1057
Scott Drennan, Gaurav Kumar, Shaoping Quan, Mingjie Wang
Abstract Controlling NOx emissions from vehicles is a key aspect of meeting new regulations for cars and trucks across the world. Selective Catalytic Reduction (SCR) with urea-water injection is a NOx reduction option that many engine manufacturers are adopting. The performance of urea-water spray evaporation and mixing upstream of an SCR catalyst is critical in obtaining reliable NOx reduction. Achieving this goal requires good ammonia and NOx distribution upstream of the SCR catalyst brick. Computational Fluid Dynamic (CFD) simulations of urea-water injection systems have become an important development and diagnostic tool for designers. An effective modeling approach for urea/SCR must include spray distribution, evaporation, urea kinetics, wall interactions and heat transfer. Designers are also interested in reducing mesh generation time to expedite geometry design changes and optimizing mesh size for accuracy and solution time.
2015-04-14
Technical Paper
2015-01-1078
Zhigang Chai, Fujun Zhang, Bolan Liu, Ying Huang, Xiaowei Ai
Abstract It is found that biodiesel has a great potential to reduce the nitrogen oxides (NOx) and soot emissions simultaneously in low temperature combustion (LTC) mode. The objective of this study is to investigate the combustion and emission characteristics of 20% biodiesel blend diesel fuel (B20) under several exhaust gas recirculation (EGR) conditions for LTC application. An experimental investigation of B20 was conducted on a four-stroke common rail direct injection diesel engine at 2000rpm and 25% load condition. The EGR ratio was adjusted from 10% to 66%, and the injection pressure was tuned from 100MPa to 140MPa. The result showed that B20 generated less soot emission than conventional diesel with increasing EGR ratio, especially when the EGR ratio was beyond 30%. Soot emission increased with increasing EGR ratio up to 50% EGR, after which there is a steep decrease in particular matter (PM).
2015-04-14
Technical Paper
2015-01-0903
Neeraj Mittal, Pradeep Patanwal, M Sithananthan, M Subramanian, Ajay Kumar Sehgal, R Suresh, B P Das
Abstract N-butanol is a promising alternative fuel which needs no engine modification when used as a blend with diesel. The miscibility of n-butanol with diesel is excellent in a wide range of blending ratios. N-butanol has high oxygen content and a comparable energy content, specific gravity and viscosity to that of diesel, which makes it attractive for diesel engines as an alternative fuel. An experimental investigation was conducted to assess the performance of a new generation passenger car with respect to power, fuel economy (FE) and mass emission using 5, 10 and 20 percent (by vol.) n-butanol blends with diesel (NB). Computer controlled DC motor driven chassis dynamometer, AVL AMA I60 mass emission measuring system and AVL FSN smoke meter were used for measuring wide open throttle (WOT) power, road load simulation (RLS) fuel economy, mass emissions and smoke in WOT and steady speed driving conditions.
2015-04-14
Technical Paper
2015-01-0905
Seyed Hadavi, Buland Dizayi, Hu Li, Alison Tomlin
Abstract To maximize CO2 reduction, refined straight used cooking oils were used as a fuel in Heavy Goods Vehicles (HGVs) in this research. The fuel is called C2G Ultra Biofuel (C2G: Convert to Green Ltd) and is a fully renewable fuel made as a diesel replacement from processed used cooking oil, used directly in diesel engines specifically modified for this purpose. This is part of a large demonstration project involving ten 44-tonne trucks using C2G Ultra Biofuel as a fuel to partially replace standard diesel fuels. A dual fuel tank containing both diesel and C2G Ultra Biofuel and an on-board fuel blending system-Bioltec system was installed on each vehicle, which is able to heat the C2G Ultra Biofuel and automatically determine the required blending ratio of diesel and C2G Ultra Biofuel according to fuel temperature and engine load. The engine was started with diesel and then switched to C2G Ultra Biofuel under appropriate conditions.
2015-04-14
Technical Paper
2015-01-0910
Lei Zhou, Benedikt Heuser, Michael Boot, Florian Kremer, Stefan Pischinger
Abstract Lignocellulosic biomass consists of (hemi-) cellulose and lignin. Accordingly, an integrated biorefinery will seek to valorize both streams into higher value fuels and chemicals. To this end, this study evaluated the overall combustion performance of both cellulose- and lignin derivatives, namely the high cetane number (CN) di-n-butyl ether (DnBE) and low CN anisole, respectively. Said compounds were blended both separately and together with EN590 diesel. Experiments were conducted in a single cylinder compression ignition engine, which has been optimized for improved combustion characteristics with respect to low emission levels and at the same time high fuel efficiency. The selected operating conditions have been adopted from previous “Tailor-Made Fuels from Biomass (TMFB)” work.
2015-04-14
Technical Paper
2015-01-1065
Piotr Bielaczyc, Joseph Woodburn, Andrzej Szczotka
Abstract Due to concern over emissions of greenhouse gases (GHG; particularly carbon dioxide - CO2), energy consumption and sustainability, many jurisdictions now regulate fuel consumption, fuel economy or exhaust emissions of CO2. Testing is carried out under laboratory conditions according to local or regional procedures. However, a harmonized global test procedure with its own test cycle has been created: the World Harmonized Light Vehicles Test Cycle - WLTC. In this paper, the WLTC is compared to the New European Driving Cycle (NEDC) and the FTP-75 cycle used in the USA. A series of emissions tests were conducted at BOSMAL on a chassis dynamometer in a Euro 6-complaint test facility to determine the impact of the test cycle on CO2 emissions and fuel consumption. While there are multiple differences in the test cycles in terms of dynamicity, duration, distance covered, mean/maximum speed, etc, differences in results obtained over the three test cycles were reasonably limited.
2015-04-14
Technical Paper
2015-01-1083
Robert L. Russell, Kent Johnson, Thomas Durbin, Patrick P. Chen, Jasna Tomic, Richard Parish
Abstract Emissions, fuel economy, and performance are determined over a light and a heavy driving cycle designed to represent the vehicles in-use driving patterns. The vehicles are 2010 class 8 Freightliner tractor trucks equipped with Cummins engines with Selective Catalytic Reduction and Diesel Particulate Filter emission control systems. The hybrid has lower carbon dioxide emissions, better fuel economy, and nitrogen oxide emissions statistically the same as the conventional. The CO emissions are well below the standards for both vehicles, but they are higher from the hybrid. The higher CO emissions for the hybrid are primarily related to the cooling of the Diesel Oxidation Catalyst (DOC) during the standard 20 minute key-off soak between repeats of the driving cycles. With a 1 minute key-off soak the CO emissions from the hybrid are negative.
2015-04-14
Technical Paper
2015-01-1162
Frank Atzler, Michael Wegerer, Fabian Mehne, Stefan Rohrer, Christoph Rathgeber, Sebastian Fischer
Abstract Modern vehicles need to fulfil challenging requirements with respect to emissions, noise and fuel consumption. Up to the EU5 legislation a sound steady state application was sufficient for passenger car Diesel engines to meet these requirements, and fuel consumption was less in the focus than the emissions of nitrous oxides and soot, hydrocarbons and carbon monoxide. Future legislation will require not only tighter limits in emissions but additionally will set fuel consumption targets. More demanding drive cycles will make it even more difficult to achieve these targets. Additional to measures on the combustion engine, moderate electrification for energy recuperation as well as the supply of electrical generated torque to the drive train will increasingly find its way into modern passenger cars. The presence of an electric machine can be used not only to reduce the fuel consumption but also the emissions of the combustion engine.
2015-04-14
Technical Paper
2015-01-1259
Tapio Pohjalainen, Martti Larmi
Abstract This study presents a novel crank mechanism which enables easy and fast compression ratio adjustment. The novel crank mechanism and piston travel are explained and highlighted. The basic idea is that eccentric gear is installed on a crankshaft web. Eccentric gear is fitted to the big end of the connection rod and eccentricity is controlled by rotating the control gear a discrete amount. Thus the position of eccentricity is varied and controls an effective stroke length. The compression ratio is adjusted to best fit current load demand, either optimizing fuel efficiency or engine power and torque. Adjustments are individual to each cylinder. The system is capable of adjusting from min to max within 10 milliseconds [ms]. Emphasis is on reduction of CO2 emissions and reducing fuel consumption, especially at part load condition. The governing mechanical equations are presented.
2015-04-14
Journal Article
2015-01-1306
Jeremy S. Neubauer, Eric Wood, Ahmad Pesaran
Abstract Battery second use-putting used plug-in electric vehicle (PEV) batteries into secondary service following their automotive tenure-has been proposed as a means to decrease the cost of PEVs while providing low cost energy storage to other fields (e.g., electric utility markets). To understand the value of used automotive batteries, however, we must first answer several key questions related to battery degradation, including: How long will PEV batteries last in automotive service? How healthy will PEV batteries be when they leave automotive service? How long will retired PEV batteries last in second-use service? How well can we best predict the second-use lifetime of a used automotive battery? Under the support of the U.S. Department of Energy's Vehicle Technologies Office, the National Renewable Energy Laboratory has developed a methodology and the requisite tools to answer these questions, including the Battery Lifetime Simulation Tool (BLAST).
2015-04-14
Technical Paper
2015-01-1631
Michinori Tani, Atsuhiro Miyauchi, Yoshiaki Matsuzono
Abstract Recently, automotive emission regulations are being further tightened, such as the Tier III/LEV III in the U.S. As a result, reducing cost of after-treatment systems to meet these strict regulations has become an urgent issue, and then the demand for high-precision air-fuel ratio (A/F) control which can achieve this cost reduction is high [1]. On the other hand, in order to meet rapidly changing market needs, it is becoming difficult to keep enough development periods that enable sufficient calibration by trial-and-error, such as feedback-gain calibration. This leads to an increase in three-way catalytic converter costs in some cases. For these reasons, it is necessary to construct control system that can make full use of hardware capabilities, can shorten development periods regardless of the skill level of engineers.
2015-04-14
Technical Paper
2015-01-1648
Hendrik Golzke, Heiko Holler, Wolfgang Friedrich, Philippe Leick, Ulrich Schoenauer, Andreas Dreizler
Abstract The spatial distribution of internal exhaust gas recirculation (EGR) is evaluated in an optically accessible direct injection spark ignition engine using near infrared laser absorption to visualize the distribution of the H2O molecule. The obtained overall internal exhaust gas recirculation compares well to gas-exchange cycle calculations and the spatial distributions are consistent with those measured with inverse LIF. The experimental procedures described in this report are designed to be simple and rapidly implemented without the need to resort to unusual optical components. The necessary spectral data of the selected absorption line is obtained from the HITEMP database and is validated with prior experiments carried out in a reference cell. Laser speckle in the images is effectively reduced using a ballistic diffuser.
2015-04-14
Technical Paper
2015-01-1639
Indranil Brahma, Odinmma Ofili, Matthew Campbell, Henrique Chiang, Vincent Giralo, Peter Stryker, Daniel Johnson, Aaron Clark
Abstract EGR flow rate measurements on production engines are commonly made using orifices or flow nozzles. These devices increase the exhaust pressure resulting in an increase in fuel consumption. Further, they are accurate and recommended only for steady state flow, and not pulsating flow encountered in engines. In this work measurements made at the EGR cooler, such as the pressure drop across it and the inlet and outlet temperatures, have been examined for their ability to predict mass flow rate through the cooler. Direct measurements of pulsating flow through an EGR cooler were made by routing all of the engine exhaust flow through the cooler while making accurate measurements of the air and fuel flowing into the engine. Based on dimensional arguments, the flow resistance of the EGR cooler was characterized by a loss coefficient within the standard head loss energy equation.
2015-04-14
Technical Paper
2015-01-1638
Dejan Kihas, Michael R. Uchanski
Recently, numerous researchers and Original Equipment Manufacturers (OEMs) have developed diesel engine-out nitrogen oxides (NOx) estimation algorithms that are capable of running in real-time on production Electronic Control Units (ECUs). These are generally referred to as virtual sensors or inferential sensors. NOx estimators are typically installed to improve On-Board Diagnostics (OBD) monitors or to lower bill of material costs by replacing physical NOx sensors. This paper reviews the literature of on-ECU NOx models in order to document the state of the art and identify directions for future work. The discussion includes applications of NOx estimators, accuracy of NOx estimators, required sensor inputs, sources of error, calibration effort, and ECU resource consumption.
2015-04-14
Technical Paper
2015-01-1637
SeungBum Kim, SeongMin Park, DongUk Han
Abstract This paper focuses on the vehicle test result of the US fuel economy test cycles such as FTP75, HWY and US06 with model based Cooled EGR system. Cooled EGR SW function was realized by Model Based Development (internal rapid prototyping) using iRPT tool. With EGR, mixing exhaust gas with clean air reduces the oxygen concentration in the cylinder charge, as a result, the combustion process is slowed, and the combustion temperature drops. This experiment confirmed that the spark timing was more advanced without knocking and manifold pressure was increased in all cases with EGR. A positive potential of fuel economy improvement on FTP mode, US06 mode have seen in this experiment but not for HWY where the engine load is quite low and the spark advance is already optimized. As a result, fuel economy was increased by maximum 3.3% on FTP, 2.7% on US06, decreased by 0.3% on HWY mode respectively with EGR.
2015-04-14
Technical Paper
2015-01-1684
KV Shivaprasad, PR Chitragar, GN Kumar
Abstract This article experimentally characterizes the combustion and emission parameters of a single cylinder high speed SI engine operating with different concentrations of hydrogen with gasoline fuel. For this purpose, the conventional carbureted high speed SI engine was modified into an electronically controllable engine, wherein ECU was used to control the injection timings and durations of gasoline. The experiments have been conducted for different engine speeds at various throttle positions. The experimental results demonstrated that engine brake power and brake thermal efficiency increased to certain extent and then decreases with the increase of hydrogen percentage in the fuel blend. The experimental results revealed that heat release and cylinder pressure increased with addition of hydrogen fraction till 20%. It also showed the reduction in HC and CO emissions in comparison with pure gasoline.
2015-04-14
Technical Paper
2015-01-1072
Aron D. Butler, Rafal A. Sobotowski, George J. Hoffman, Paul Machiele
Abstract The EPAct/V2/E-89 gasoline fuel effects program collected emissions data for 27 test fuels using a fleet of 15 high-sales cars and light trucks from the 2008 model year (all with port fuel injection). The test fuel matrix covered values of T50, T90, vapor pressure, ethanol content, and total aromatic content spanning ranges typical of market gasolines. Emission measurements were made over the LA92 cycle at a nominal temperature of 24°C (75°F). The resulting emissions database of 956 tests includes a particulate matter (PM) mass measurement for each. Emission models for PM fuel effects were fit based on terms for which the fuel matrix was originally optimized, with results published by EPA in a 2013 analysis report. This paper presents results of a subsequent modeling analysis of this PM data using the PM Index fuel parameter, and compares these models to the original versions.
2015-04-14
Technical Paper
2015-01-1250
Nisar Al-Hasan, Johannes Beer, Jan Ehrhard, Thomas Lorenz, Ludwig Stump
Abstract In the past few years the gasoline direct injection (GDI) downsizing approach was the dominating gasoline engine technology used to reduce CO2 emission and to guarantee excellent transient performance. Forecasts for the next several years indicate that the worldwide market share of GDI engines will grow further. By 2022 it is expected that the gasoline DI engine will be the most popular combustion engine for passenger car application. However in the future the gasoline engine will have to comply with more stringent emission and CO2 standards. The European legislation demands a fleet average CO2 emission of 95g/km latest by 2021. Therefore, CO2 emission improvement, without compromising driveability, is the major goal of powertrain development. The perspective of more stringent CO2 and emission legislation in highly loaded drive cycle necessitates major development efforts.
2015-04-14
Journal Article
2015-01-1683
Bernie Porter, Hugh Blaxill, Noor Jariri
Abstract The 2025 Corporate Average Fleet Economy (CAFE) fuel economy regulations are a significant challenge to the automotive industry. These regulations require dramatic increases in vehicle fleet fuel economy. This paper will identify and analyze a portfolio of technologies that have the potential to achieve the 2025 CAFE fuel economy targets, focusing on powertrain enhancements. The study uses a MAHLE Powertrain developed fleet modeling tool and a range of vehicle technologies and powertrain data taken from MAHLE's global research and development activities. Powertrain technologies considered include extreme engine downsizing, dilute combustion, friction reduction, hybridization, diesel and alternative fuels. The vehicle technologies analyzed include vehicle light weighting, reduced rolling resistance, advanced transmissions and improved aerodynamics.
2015-04-14
Collection
This technical paper collection focuses on particle emissions from combustion engines, including measurement and testing methods, and the effects of changes in fuel composition. Papers also cover the topics of the environmental and health effects of elemental carbon and organic carbon that constitutes solid cored particles plus the environmental and health effects of secondary organic aerosol emissions. This includes particulate emissions from both gasoline and diesel engines.
2015-04-14
Technical Paper
2015-01-0863
Hideyuki Ogawa, Peilong Zhao, Taiki Kato, Gen Shibata
Abstract Dual fuel combustion with premixed natural gas as the main fuel and diesel fuel as the ignition source was investigated in a 0.83 L, single cylinder, DI diesel engine. At low loads, increasing the equivalence ratio of natural gas to around 0.5 with intake throttling makes it possible to reduce the THC and CO emissions as well as to improve the thermal efficiency. At high loads, increasing the boost pressure moderates the combustion, but increases the THC and CO emissions, resulting in deterioration of the thermal efficiency. The EGR is essential to suppress the rapid combustion. As misfiring occurs with a compression ratio of 14.5 and there is excessively rapid combustion with 18.5 compression ratio, 16.5 is a suitable compression ratio.
2015-04-14
Journal Article
2015-01-1034
Homayoun Ahari, Michael Smith, Michael Zammit, Kenneth Price, Jason Jacques, Thomas Pauly, Lin Wang
Significant reduction in Nitrogen Oxide (NOx) emissions will be required to meet LEV III/Tier III Emissions Standards for Light Duty Diesel (LDD) passenger vehicles. As such, Original Equipment Manufacturers (OEMs) are exploring all possible aftertreatment options to find the best balance between performance, durability and cost. The primary technology adopted by OEMs in North America to achieve low NOx levels is Selective Catalytic Reduction (SCR). The critical parameters needed for SCR to work properly are: an appropriate reductant such as ammonia (NH3) provided as Diesel Exhaust Fluid (DEF), which is an aqueous urea solution 32.5% concentration in weight with water (CO(NH2)2 + H2O), optimum operating temperatures, and optimum nitrogen dioxide (NO2) to NOx ratios (NO2/NOx). The NO2/NOx ratio is most influenced by Precious Group Metals (PGM) containing catalysts upstream of the SCR catalyst.
2015-04-14
Technical Paper
2015-01-1026
Padmanabha Reddy Ettireddy, Adam Kotrba, Thirupathi Boningari, Panagiotis Smirniotis
Abstract The main objective of this work is to develop a low-temperature SCR catalyst for the reduction of nitrogen oxides at cold start, low-idle and low-load conditions. A series of metal oxide- incorporated beta zeolite catalysts were prepared by adopting incipient wetness technique, cation-exchange, deposition-precipitation and other synthesis techniques. The resulting catalysts were characterized and tested for reduction of NOx in a fixed bed continuous flow quartz micro-reactor using ammonia as the reductant gas. Initial catalyst formulations have been exhibited good NOx reduction activity at low-temperatures. These catalyst formulations showed a maximum NOx conversion in the temperature range of 100 - 350°C. Besides, more experiments were performed with the aim of optimizing these formulations with respect to the metal atomic ratio, preparation method, active components and supported metal type.
2015-04-14
Journal Article
2015-01-1040
Harsha K. Nanjundaswamy, Joel Deussen, Roger Van Sickle, Dean Tomazic, Tamas Szailer, Michael Franke, Matthias Kotter, Thomas Koerfer
Abstract Upcoming motor vehicle emission regulations, such as California's LEVIII, continue to tighten emission limitations in diesel vehicles. These increasingly challenging emission requirements will be met by improving the combustion process (reducing engine-out emissions), as well as improving the exhaust gas aftertreatment efficiency. Furthermore, intricate On-Board Diagnostics (OBD) systems are required to properly diagnose and meet OBD regulation requirements for complex aftertreatment systems. Under these conditions, current monitoring strategies are unable to guarantee reliable detection of partially failed systems. Additionally, new OBD regulations require aftertreatment systems to be diagnosed as a whole. This paper covers potential OBD strategies for LEVIII aftertreatment concepts with regard to regulation compliance and robustness, while striving to use existing sensor concepts.
2015-04-14
Technical Paper
2015-01-0989
Steve Schiller, Mark Brandl, Bruce Hoppenstedt, Korneel De Rudder
Abstract Diesel engine NOx emissions requirements have become increasingly stringent over the past two decades. Engine manufacturers have shown through the use of EGR and SCR technology that these requirements can be met. However, the desires for improved fuel efficiency, lower overall cost, and potential legislation to reduce NOx levels further increase the demand for higher DEF dosing rates. To meet this demand, a new DEF mixing technology has been developed. This paper describes the development methods used to create a compact, in-pipe mixer which utilizes an optimized wire mesh along with swirling flow to permit high DEF dosing rates without deposit formation. Its excellent mixing characteristics allowed for high NOx reduction to be achieved. Utilization of this technology makes it possible to reduce regeneration frequency, reduce the overall size of the SCR system, possibly eliminate the EGR system, and improve fuel efficiency through combustion enhancements.
2015-04-14
Technical Paper
2015-01-1730
Luca Romani, Giovanni Vichi, Giovanni Ferrara, Francesco Balduzzi, Paolo Trassi, Jacopo Fiaschi, Federico Tozzi
Abstract High specific fuel consumption and pollutant emissions are the main drawbacks of the small crankcase-scavenged two-stroke engine. The symmetrical port timing combined with a carburetor or an indirect injection system leads to a lower scavenging efficiency than a four-stroke engine and to the short-circuit of fresh air-fuel mixture. The use of fuel supply systems as the indirect injection and the carburetor is the standard solution for small two-stroke engine equipment, due to the necessity of reducing the complexity, weight, overall dimensions and costs. This paper presents the results of a detailed study on the application of an innovative Low Pressure Direct Injection system (LPDI) on an existing 300 cm3 cylinder formerly equipped with a carburetor. The proposed solution is characterized by two injectors working at 5 bar of injection pressure.
2015-04-14
Journal Article
2015-01-0391
Yoshihiro Sukegawa, Kazuhiro Oryoji
Abstract A 3D simulation technique to estimate density of particulate matter (PM) from spark ignition (SI) gasoline engines is proposed. The technique is based on a two-equation model consisting of coupled conservation equations of soot particle number and mass and fluid transportation equations. The nucleation rate of soot particles was obtained from a database built by simulation of elementary reaction with the proposed technique. Two approaches were explored to obtain the nucleation rate. One involves 0-dimensinal SI simulation and the other involves 1-dimensinal flame propagation simulation. The estimation results were verified with measurement data obtained with a single cylinder SI engine a homogeneous pre-mixed fuel was supplied. It was confirmed that appropriate results could be obtained with the 1-dimensional approach for the nucleation rate model.
2015-04-14
Journal Article
2015-01-0744
Terrence Alger, Raphael Gukelberger, Jess Gingrich, Barrett Mangold
Abstract The use of cooled EGR as a knock suppression tool is gaining more acceptance worldwide. As cooled EGR become more prevalent, some challenges are presented for engine designers. In this study, the impact of cooled EGR on peak cylinder pressure was evaluated. A 1.6 L, 4-cylinder engine was operated with and without cooled EGR at several operating conditions. The impact of adding cooled EGR to the engine on peak cylinder pressure was then evaluated with an attempt to separate the effect due to advanced combustion phasing from the effect of increased manifold pressure. The results show that cooled EGR's impact on peak cylinder pressure is primarily due to the knock suppression effect, with the result that an EGR rate of 25% leads to an almost 50% increase in peak cylinder pressure at a mid-load condition if the combustion phasing is advanced to Knock Limited Spark Advance (KLSA). When combustion phasing was held constant, increasing the EGR rate had almost no effect on PCP.
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