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Viewing 91 to 120 of 21875
2017-03-28
Technical Paper
2017-01-0999
Yuanzhou Xi, Nathan Ottinger, Z. Gerald Liu
Abstract Natural gas powered vehicles are attractive in certain applications due to their lower emissions in general than conventional diesel engines and the low cost of natural gas. For stoichiometric natural gas engines, the aftertreatment system typically consists only of a three-way catalyst (TWC). However, increasingly stringent NOx and methane regulations challenge current TWC technologies. In this work, a catalyst reactor system with variable lean/rich switching capability was developed for evaluating TWCs for stoichiometric natural gas engines. The effect of varying frequency and duty-cycle during lean/rich gas switching experiments was measured with a hot-wire anemometer (HWA) due to its high sensitivity to gas thermal properties. A theoretical reactor gas dispersion model was then developed and validated with the HWA measurements. The model is capable of predicting the actual lean/rich gas exposure to the TWC under different testing conditions.
2017-03-28
Technical Paper
2017-01-0998
Kurtis James Irwin, Jonathan Stewart, Roy Douglas, Andrew Woods, Richard O’Shaughnessy, Andrew Pedlow, Rose Mary Stalker
Abstract Accelerated aging of automotive catalysts has become a routine process for the development of new catalytic formulations and for homologation of vehicle emissions. In the standard approach, catalyst samples are subjected to temperatures in excess of 800°C on a predefined test cycle and aged for precise timescales representative of certain vehicle mileage. The high temperature feed gas is traditionally provided by a large gasoline engine but, increasingly, alternative bench-aging techniques are being applied as these offer more precise control and considerable cost savings, as well as offering more development possibilities. In the past few years, emissions control of light duty vehicles has become increasingly prominent as more stringent emissions legislations require more complex after-treatment systems. Aging of the catalysts are not fully understood as they are subjected to many varying environments, including temperature and gas concentrations.
2017-03-28
Technical Paper
2017-01-1006
Fadzli Ibrahim, Wan Mohd Faizal Wan Mahmood, Shahrir Abdullah, Mohd Radzi Abu Mansor
Abstract Application of computational method in studying soot formation and its characteristics has become more preferable in today’s automotive field. Current developments of computer programs with higher precision mathematical models enable simulation results to become closer to the real engine combustion phenomena. In the present study, investigation on soot has been performed using various soot models with different levels of complexity, from simple two-step Hiroyasu-NSC soot model to the detailed-kinetic soot model. Detailed soot models, Particulate Mimic (PM) which is based on methods of moment and Particulate Size Mimic (PSM) which is based on sectional method, are applied in this study. Result of soot mass from Hiroyasu-NSC model provides 120% error compare to experimental result, while both detailed models provide an acceptable error of 7%.
2017-03-28
Technical Paper
2017-01-1007
Piotr Bielaczyc, Andrzej Szczotka, Joseph Woodburn
Abstract This paper reports testing conducted on multiple vehicle types over two European legislative driving cycles (the current NEDC and the incoming WLTC), using a mixture of legislative and non-legislative measurement devices to characterise the particulate emissions and examine the impact of the test cycle and certain vehicle characteristics (engine/fuel type, idle stop system, inertia) on particulate emissions. European legislative measurement techniques were successfully used to quantify particle mass (PM) and number (PN); an AVL Microsoot sensor was also used. Overall, the two driving cycles used in this study had a relatively limited impact on particulate emissions from the test vehicles, but certain differences were visible and in some cases statistically significant.
2017-03-28
Technical Paper
2017-01-1012
Sunil Kumar Pathak, Vineet sood, Yograj Singh, Salim Abbasbhai Channiwala
Abstract In developing countries like India, large numbers of portable gensets are used as a power source due to the scarcity of grid power supply. The portable gensets, ranging from 0.5 kW to 5 kW are very popular in the residential areas, for example, small restaurants, and shopping complexes, etc. These gensets are using various fuels like gasoline, diesel, LPG, and kerosene in small internal combustion engines. Such engines are the significant source of air pollution, as these are running in the vicinity of populated areas and higher human exposure to these pollutants.Theses gensets are regulated by exhaust and noise emissions norms, set by statutory bodies like the ministry of environment and forest and central pollution control board of India.
2017-03-28
Technical Paper
2017-01-0985
Joachim Demuynck, Cecile Favre, Dirk Bosteels, Heather Hamje, Jon Andersson
Abstract The market share of Gasoline Direct Injection (GDI) vehicles has been increasing, promoted by its positive contribution to the overall fleet fuel economy improvement. It has however been reported that this type of engine is emitting more ultrafine particles than the Euro 6c Particle Number (PN) limit of 6·1011 particles/km that will be introduced in Europe as of September 2017 in parallel with the Real Driving Emission (RDE) procedure. The emissions performance of a Euro 6b GDI passenger car was measured, first in the OEM build without a Gasoline Particulate Filter (GPF) and then as a demonstrator with a coated GPF in the underfloor position. Regulated emissions were measured on the European regulatory test cycles NEDC and WLTC and in real-world conditions with Portable Emissions Measurement Systems (PEMS) according to the published European RDE procedure (Commission Regulation (EU) 2016/427 and 2016/646).
2017-03-28
Technical Paper
2017-01-1009
Yajun Wang, Xingyu Liang, Yuesen Wang, Xiuxiu Sun, Hanzhengnan Yu, Xikai Liu
In this paper, the influences of metallic content of lubricating oils on diesel particles were investigated. Three lubricating oils with different levels of metallic content were used in a 2.22 Liter, two cylinders, four stroke, and direct injection diesel engine. 4.0 wt. % and 8 wt. % antioxidant and corrosion inhibitor (T202) were added into baseline lubricating oil to improve the performance respectively. Primary particle diameter distributions and particle nanostructure were compared and analyzed by Transmission Electron Microscope. The graphitization degrees of diesel particles from different lubricating oils were analyzed by Raman spectroscopy. Conclusions drawn from the experiments indicate that the metallic content increases the primary particles diameter at 1600 rpm and 2200 rpm. The primary particles diameter ranges from 5 nm to 65 nm and the distribution conformed to Gaussian distribution.
2017-03-28
Technical Paper
2017-01-0983
Masaaki Ito, Frank Katsube, Yasuhiko Hamada, Hiroaki Ishikawa, Tsuyoshi Asako
Abstract Particle Number (PN) regulation was firstly introduced for European light-duty diesel vehicles back in 2011[1]. Since then, PN regulation has been and is being expanded to heavy-duty diesel vehicles and non-road diesel machineries. PN regulation will also be expanded to China and India around 2020 or later. Diesel Particulate Filter (DPF) is significant factor for the above-mentioned PN regulation. This filter technology is to be continuously evolved for the near future tighter PN regulation. Generally, PN filtration performance test for filter technology development is carried out with chassis dynamometer, engine dynamometer or simulator [2]. This paper describes a simplified and relatively quicker alternative PN filtration performance test method for accelerating filter technology development compared to the current test method.
2017-03-28
Technical Paper
2017-01-1016
Charles Schenk, Paul Dekraker
Abstract EPA has been benchmarking engines and transmissions to generate inputs for use in its technology assessments supporting the Midterm Evaluation of EPA’s 2017-2025 Light-Duty Vehicle greenhouse gas emissions assessments. As part of an Atkinson cycle engine technology assessment of applications in light-duty vehicles, cooled external exhaust gas recirculation (cEGR) and cylinder deactivation (CDA) were evaluated. The base engine was a production gasoline 2.0L four-cylinder engine with 75 degrees of intake cam phase authority and a 14:1 geometric compression ratio. An open ECU and cEGR hardware were installed on the engine so that the CO2 reduction effectiveness could be evaluated. Additionally, two cylinders were deactivated to determine what CO2 benefits could be achieved. Once a steady state calibration was complete, two-cycle (FTP and HwFET) CO2 reduction estimates were made using fuel weighted operating modes and a full vehicle model (ALPHA) cycle simulation.
2017-03-28
Technical Paper
2017-01-1019
Bentolhoda Torkashvand, Andreas Gremminger, Simone Valchera, Maria Casapu, Jan-Dierk Grunwaldt, Olaf Deutschmann
Abstract The effect of increased pressure relevant to pre-turbine catalyst positioning on catalytic oxidation of methane over a commercial Pd-Pt model catalyst under lean conditions is investigated both experimentally and numerically. The possible gas phase reactions due to high temperature and pressure were tested with an inert monolith. Catalyst activity tests were conducted for both wet and dry gas mixtures and the effect of pressure was investigated at 1, 2 and 4 bar. Aside from the water in the inlet stream, the water produced by oxidation of methane in dry feed inhibited the activity of the catalyst as well. Experiments were carried out to check the effect of added water in the concentration range of water produced by methane oxidation on the catalyst activity. Based on the experimental results, a global oxidation rate equation is proposed. The reaction rate expression is first order with respect to methane and -1.15 with respect to water.
2017-03-28
Technical Paper
2017-01-1020
Finn Tseng, Imad Makki, Pankaj Kumar, Robert Jentz, Aed Dudar
Abstract Engine-Off Natural Vacuum (EONV) principles based leak detection monitors are designed to determine the presence of a small leak in the fuel tank system. It was introduced to address the ever more stringent emission requirement (currently at 0.02”) for gasoline engine equipped vehicles as proposed by the Environmental Protection Agency (EPA) and California Air Resources Board (CARB) in the United States [2, 3]. Other environmental protection agencies including the ones in EU and China will be adopting similar regulations in the near future. Due to its sensitivity to known noise factors such as the ambient temperature, barometric pressure, drive pattern and parking angle, it has been historically a lower performing monitor that is susceptible to warranty cost or even voluntary recalls. The proposed new model based monitor utilizes production pressure signal and newly instrumented temperature sensors [15].
2017-03-28
Technical Paper
2017-01-0382
Oscar Hernandez Cervantes, Antonio Espiritu Santo Rincon
The development of an automatic control system for a towing dynamometer used for testing is described in this paper. The process involved the deployment of new power electronics, a TELMA retarder, instrumentation and a human machine interface (HMI). The control system was developed with a low cost open source platform for further function expansion, data acquisition and communication with other devices. This system is intended as a novel solution that will allow closed loop automated tests for engine calibration.
2017-03-28
Journal Article
2017-01-0388
Haeyoon Jung, MiYeon Song, Sanghak Kim
This paper proposes the Off-cycle credit alternative test methodology for Semi-transparent solar panel integrated on Automobile roof glass to achieve the CO2 credits from the Environmental Protection Agency (EPA) & the National Highway Traffic Safety Administration (NHTSA). Manufactures offer the option to put solar cells on the roof of a vehicle for reducing cabin ambient temperature. However, Hyundai Motors develops the semi-transparent solar roof with a controller to provide electric energy for vehicles. This electrical energy cannot be accounted for on the current EPA cycles either the two cycle test or the five-cycle test. Therefore, the manufacture has to establish the methodology based on solar system for vehicles. In order to improve the efficiency of our solar system and to calculate reduced CO2 emission, we studied useable solar energy in driving condition other than peak power in standard test condition(@ 25℃, 1Sun).
2017-03-28
Technical Paper
2017-01-0580
Zainal Abidin, Kevin Hoag, Nicholas Badain
The promising D-EGR engine results achieved in the test cell, and then in a vehicle demonstration have led to exploration of further possible applications. A study has been conducted to explore the use of D-EGR engines as a lower cost replacement for medium duty diesel engines in trucks and construction equipment. However, medium duty engines have larger displacement, and tend to require high torque at lower engine speeds than their automobile counterparts. Transmission and final drive gearing can be utilized to operate the engine at higher speeds, but this penalizes life-to-overhaul. It is therefore important to ensure that D-EGR combustion system performance can be maintained with a larger cylinder bore, and with high specific output at relatively low engine speeds. Based on application projections studied in the study, an engine having a 107mm bore and 124mm stroke, operating at 2000 rpm at 17 bar Brake Mean Effective Pressure (BMEP) was selected as representative.
2017-03-28
Journal Article
2017-01-0647
Bradley Denton, Christopher Chadwell, Raphael Gukelberger, Terrence Alger
The Dedicated EGR (D-EGR®) engine has shown improved efficiency and emissions while minimizing the challenges of traditional cooled EGR. The concept combines the benefits of cooled EGR with additional improvements resulting from in-cylinder fuel reformation. The fuel reformation takes place in the dedicated cylinder, which is also responsible for producing the diluents for the engine (EGR). The D-EGR system does present its own set of challenges. Because only one out of four cylinders is providing all of the dilution and reformate for the engine, there are three “missing” EGR pulses and problems with EGR distribution to all 4 cylinders exist. In testing, distribution problems were realized which led to poor engine operation. To address these spatial and temporal mixing challenges, a distribution mixer was developed and tested which improved cylinder-to-cylinder and cycle-to-cycle variation of EGR rate through improved EGR distribution.
2017-03-28
Journal Article
2017-01-0695
Ezio Spessa, Stefano D'Ambrosio, Daniele Iemmolo, Alessandro Mancarella, Roberto Vitolo, Gilles Hardy
In order to meet the continuously stringent standards in terms of pollutant emissions and fuel consumption from combustion engines of road vehicles, several investigations have been recently conducted about in-cylinder techniques and aftertreatment systems. In particular, the control of the fuel injected quantity and of the center of combustion (MFB50) performed cylinder-by-cylinder can effectively provide advantages in terms of pollutant formation and fuel consumption. In the present investigation, an experimental comparison among different control strategies is performed in a heavy-duty 3.0 L Euro VI diesel engine. The first control strategy is the standard one originally implemented in the ECU, whereas the other two are referred to as model-based and pressure-based combustion controls and have been implemented by means of rapid prototyping and proper hardware device connected to the ECU.
2017-03-28
Journal Article
2017-01-0911
Krishna Chilumukuru, Aniket Gupta, Michael Ruth, Michael Cunningham, Govindarajan Kothandaraman, Lasitha Cumaranatunge, Howard Hess
Light duty emission certification levels such as Tier 2 Bin 2 (equivalent of Tier 3 Bin 30) are 70% and 88% lower in NOx and HC respectively from current Tier 2 Bin 5 level. For light duty chassis certified automotive applications, the weighting factor of the cold portion of the FTP-75 (federal transient procedure) cycle is 43% of the overall emissions certification value. NOx and HC emissions must be mitigated at much lower exhaust temperatures as compared to diesel aftertreatment systems currently in production. In this work, a novel aftertreatment architecture to improve low temperature NOx and HC conversion efficiency is proposed. This system consists of a diesel cold start concept (dCSC™) catalyst and selective catalytic reduction catalyst on filter (SCRF®) close coupled to the engine for faster warm up. Additionally, a flow-through SCR catalyst is located downstream of the SCR on DPF catalyst.
2017-03-28
Journal Article
2017-01-0909
Zhe Zhang, Mats Abom, Hans Boden, Mikael Karlsson
Air pollution caused by exhaust particulate matter (PM) from vehicular traffic is a major health issue. Increasingly strict regulations of vehicle emission have been introduced and efforts have been put on both the suppression of particulate formation inside the engine cylinders and the development of after-treatment technologies such as filters. With modern direct injected engines that produce a large number of really small sub-micron particles, the focus has increased even further and now also include a number count. The problem of calculating particle trajectories in flow ducts like vehicle exhaust systems is challenging but important to further improve the technology. The interaction between particles and oscillating flows may lead to the formation of particle groups (regions where the particle concentration is increased) yielding a possibility of realizing particle agglomeration.
2017-03-28
Journal Article
2017-01-0947
Athanasios G. Konstandopoulos, Dimitrios Zarvalis, Leonidas Chasapidis, Danis Deloglou, Nickolas Vlachos, Adam Kotrba, Ginette Anderson
Evolving marine diesel emission regulations, cause significant concern regarding reduction of emissions of oxides of nitrogen (NOx). There is therefore considerable interest to develop and validate Selective Catalytic Reduction (SCR) converters for marine diesel NOx emission control. Substrates in marine applications, need to be robust to survive high sulfur contents and offer cost and pressure drop benefits. Higher cell densities in principle offer benefits with respect to system volume and provide increased catalyst area (in direct tradeoff with increased pressure drop). However higher cell densities may become more easily plugged by deposition of soot and/or sulphate particulate, on the face of the monolithic converter, as well as on its channel walls and catalyst coating, eventually leading to flow restriction.
2017-03-28
Journal Article
2017-01-0946
Nathan Ottinger, Yuanzhou Xi, Christopher Keturakis, Z. Gerald Liu
Low-temperature (T ≤ 200°C) NOx conversion is receiving increasing research attention due to continued potential reductions in regulated NOx emissions from diesel engines. At these temperatures, ammonium salts (e.g., ammonium nitrate, ammonium (bi)sulfate, etc.) can form as a result of interactions between NH3 and NOx or SOx, respectively. These formation of these salts can reduce the availability of NH3 for NOx conversion, block active catalyst sites, and result in the formation of N2O, a regulated Greenhouse Gas (GHG). In this study, we investigate the effect of hydrothermal aging on the formation and decomposition of ammonium nitrate on a state-of-the-art Cu/zeolite selective catalytic reduction (SCR) catalyst. Reactor-based constant-temperature ammonium nitrate formation and temperature programmed oxidation (TPO) and NO titration decomposition experiments are used to characterize the effect of hydrothermal aging from 600 to 950°C.
2017-03-28
Journal Article
2017-01-0942
Joseph R. Theis, Christine Lambert
A model low temperature NOx adsorber (LTNA) consisting of Pd on a ceria/zirconia support was evaluated for NOx storage performance under lean conditions to assess its potential for adsorbing the cold-start NOx emissions on a diesel engine before the urea/SCR system becomes operational. A reactor-based transient test was performed with and without C2H4, CO/H2, and H2O in the feedgas to assess the effects of these gas species on the initial NOx storage performance. In the absence of C2H4 or CO/H2, H2O severely suppressed the NOx storage performance of the LTNA at temperatures below 100oC, presumably by blocking the storage sites. When C2H4 was included in the feedgas, H2O still suppressed the NOx storage below 100oC. However, the C2H4 significantly increased the NOx storage efficiency above 100oC, attributable to the formation of alkyl nitrites or alkyl nitrates on the catalyst.
2017-03-28
Journal Article
2017-01-0940
Jesus Emmanuel De Abreu Goes, Louise Olsson, Malin Berggrund, Annika Kristoffersson, Lars Gustafson, Mikael Hicks
Even though substantial improvements have been made for the lean NOx trap (LNT) catalyst in recent years, the durability still remains problematic because of the sulfur poisoning and sintering of the precious metals at high operating temperatures. Hence, commercial LNT catalysts were aged and tested in order to investigate their performance and activity degradation with respect to the fresh catalyst, and establish a proper correlation between the aging methods used. The target of this study is to provide useful information for regeneration strategies and optimize the catalyst management for better performance and durability. With this goal in mind, two different aging procedures were implemented in this investigation. A catalyst was field-aged in the vehicle chassis dynamometer for 100.000 km, thus exposed to real conditions. Whereas, an accelerated aging method was used by subjecting a fresh LNT catalyst at 800 °C for 24 hours in an oven under controlled conditions.
2017-03-28
Journal Article
2017-01-0930
Christine K. Lambert, Timothy Chanko, Mark Jagner, Jon Hangas, Xin Liu, James Pakko, Carl Justin Kamp
To meet future particle mass and particle number standards, gasoline vehicles may require particle control, either by way of an exhaust gas filter and/or engine modifications. Soot levels for gasoline engines are much lower than diesel engines; however, non-combustible material (ash) will be collected that can potentially cause increased backpressure, reduced power, and lower fuel economy. The purpose of this work was to examine the ash loading of gasoline particle filters (GPFs) during rapid aging cycles and at real time low mileages, and compare the filter performances to both fresh and very high mileage filters. Current rapid aging cycles for gasoline exhaust systems are designed to degrade the three-way washcoat both hydrothermally and chemically to represent full useful life catalysts. The ash generated during rapid aging is low in quantity although similar in quality to real time ash. Filters were also examined after a low mileage break-in of approximately 3000 km.
2017-03-28
Journal Article
2017-01-0958
Christopher Sharp, Cynthia C. Webb, Gary Neely, Jayant V. Sarlashkar, Sankar B. Rengarajan, Seungju Yoon, Cary Henry, Bryan Zavala
Recent 2010 emissions standards for heavy-duty engines have established a limit of oxides of nitrogen (NOx) emissions of 0.20 g/bhp-hr. However, it is projected that even when the entire on-road fleet of heavy-duty vehicles operating in California is compliant with 2010 emission standards, the National Ambient Air Quality Standards (NAAQS) requirement for ambient particulate matter and Ozone will not be achieved without further reduction in NOx emissions. The California Air Resources Board (ARB) funded a research program to explore the feasibility of achieving 0.02 g/bhp-hr NOx emissions. This paper details engine and aftertreatment NOX management requirements and model based control considerations for achieving Ultra-Low NOX levels. Data will be presented for several Advanced Technology aftertreatment technologies and the integration of those technologies with the engine calibration.
2017-03-28
Journal Article
2017-01-0956
Christopher Sharp, Cynthia C. Webb, Seungju Yoon, Michael Carter, Cary Henry
Recent 2010 emissions standards for heavy-duty engines have established a limit of oxides of nitrogen (NOx) emissions of 0.20 g/bhp-hr. However, it is projected that even when the entire on-road fleet of heavy-duty vehicles operating in California is compliant with 2010 emission standards, the National Ambient Air Quality Standards (NAAQS) requirement for ambient particulate matter and Ozone will not be achieved without further reduction in NOx emissions. The California Air Resources Board (ARB) funded a research program to explore the feasibility of achieving 0.02 g/bhp-hr NOx emissions. This paper details the work done to explore the feasibility of various configurations of Traditional Technology (diesel oxidation catalyst-diesel particulate filter-selective catalytic reduction (SCR)) and Advanced Technology (passive NOx adsorber or diesel oxidation catalyst – SCR on Filter – SCR) to demonstrate ultra-low NOx emissions from heavy-duty engines.
2017-03-28
Journal Article
2017-01-0982
Dhruvang Rathod, Mark A. Hoffman, Simona Onori
The duration over which a three way catalyst (TWC) maintains proper functionality during lambda excursions is critically impacted by aging, which affects its oxygen storage capacity (OSC). As such, emissions control strategies, which strive to maintain post TWC air-to-fuel ratios at the stoichiometric value, will benefit from an accurate estimation of TWC age. To this end, this investigation examines a method of TWC age estimation suitable for real-world transient operation. Experimental results are harvested from an instrumented test vehicle equipped with a two-brick TWC during operation on a chassis dynamometer. Four differently aged TWCs are instrumented with wideband and switch-type Lambda sensors upstream (Pre TWC location), and downstream (Mid location) of first catalyst brick.
2017-03-28
Journal Article
2017-01-0674
Benjamin Matthew Wolk, Isaac Ekoto
Abstract Pulsed nanosecond discharges (PND) can achieve ignition in internal combustion engines through enhanced reaction kinetics as a result of elevated electron energies without the associated increases in translational gas temperature that cause electrode erosion. Atomic oxygen (O), including its electronically excited states, is thought to be a key species in promoting low-temperature ignition. In this paper, high-voltage (17-24 kV peak) PND are examined in oxygen/nitrogen/carbon dioxide/water mixtures at engine-relevant densities (up to 9.1 kg/m3) through pressure-rise calorimetry and direct imaging of excited-state O-atom and molecular nitrogen (N2) in an optically accessible spark calorimeter, with the anode/cathode gap distance set to 5 mm or with an anode-only configuration (DC corona). The conversion efficiency of pulse electrical energy into thermal energy was measured for PND with secondary streamer breakdown (SSB) and similar low-temperature plasmas (LTP) without.
2017-03-28
Journal Article
2017-01-0639
Michael H. Shelby, Thomas G. Leone, Kevin D. Byrd, Frank K. Wong
Abstract Increasing compression ratio (CR) is one of the most fundamental ways to improve engine efficiency, but the CR of practical spark ignition engines is limited by knock and spark retard at high loads. A variable CR mechanism could improve efficiency by using higher CR at low loads, and lower CR (with less spark retard) at high loads. This paper quantifies the potential efficiency benefits of applying variable CR to a modern downsized, boosted gasoline engine. Load sweeps were conducted experimentally on a multi-cylinder gasoline turbocharged direct injection (GTDI) engine at several CRs. Experimental results were compared to efficiency versus CR correlations from the literature and were used to estimate the fuel economy benefits of 2-step and continuously variable CR concepts on several engine/vehicle combinations, for various drive cycles.
2017-03-28
Journal Article
2017-01-0644
Michael Pontoppidan, Adm José baeta
Abstract In a torch ignition engine system the combustion starts in a prechamber, where the pressure increase pushes the combustion jet flames through calibrated nozzles to be precisely targeted into the main combustion chamber. The paper presents the layout of the prototype engine and the developed fuel injection system. It continues with a detailed description of the performance of the torch ignition engine running on a gasoline/ethanol blend for different mixture stratification levels as well as engine speeds and loads. Also detailed analyses of specific fuel consumption, thermal and combustion efficiency, specific emissions of CO2 and the main combustion parameters are carried out. A supplementary decrease in NOX emissions was obtained by use of Brazilian pure hydrated fuel. The paper concludes presenting the main results obtained in this work, which show significant increase of the torch ignition engine performance in comparison with the commercial baseline engine.
2017-03-28
Journal Article
2017-01-0643
Thompson Lanzanova, Macklini Dalla Nora, Hua Zhao
Abstract The more strict CO2 emission legislation for internal combustion engines demands higher spark ignition (SI)engine efficiencies. The use of renewable fuels, such as bioethanol, may play a vital role to reduce not only CO2 emissions but also petroleum dependency. An option to increase SI four stroke engine efficiency is to use the so called over-expanded cycle concepts by variation of the valve events. The use of an early or late intake valve closure reduces pumping losses (the main cause of the low part load efficiency in SI engines) but decreases the effective compression ratio. The higher expansion to compression ratio leads to better use of the produced work and also increases engine efficiency. This paper investigates the effects of early and late intake valve closure strategies in the gas exchange process, combustion, emissions and engine efficiency at unthrottled stoichiometric operation.
Viewing 91 to 120 of 21875