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Viewing 1 to 30 of 14987
2017-07-10
Technical Paper
2017-28-1933
Alberto Boretti
The contribution analyses the Volkswagen emission scandal and the impacts on the perspectives of the internal combustion engine, the battery based electric car and the hydrogen based mobility. The operation of the United States Environmental Protection Agency, Volkswagen and the United States prosecutor sparked by the action of the International Council on Clean Transportation is forcing the Original Equipment Manufacturers towards an everything but rationale immediate transition to the battery based electric mobility. This transition voids the value of any improvement of the internal combustion engine (ICE), especially in the lean burn, compression ignition (CI) flavor and of a better hybridization of powertrains, both options that have much better short term perspectives than the battery based electric car.
2017-07-10
Technical Paper
2017-28-1953
Tushar Narendra Puri lng, Lalitkumar Ramujagir Soni lng, Sourabh Deshpande
The infliction of rigorous emission norms across the world has made the automobile industry to focus and dwell upon researches to reduce the engine emissions of diesel engine. Variation in injection timing has better influence on reduction of engine emissions. This paper deal with numerical simulation of 4-stroke, single cylinder, naturally aspirated, direct injection diesel engine running at 1640 RPM using CONVERGE_STUDIO CFD tool. As the piston and bowl geometry considered in this work is symmetric only 45 degree sector engine model considered for simulation over 360 degree complete engine model. To study the combustion and inside flow physics taking place inside engine cylinder more accurately and to reduce computational time, simulation from 20 bTDC during compression stroke up to 140 aTDC in the power stroke is considered as available in the literature.
2017-06-05
Technical Paper
2017-01-1782
Jobin Puthuparampil, Henry Pong, Pierre Sullivan
Abstract Large-scale emergency or off-grid power generation is typically achieved through diesel or natural gas generators. To meet governmental emission requirements, emission control systems (ECS) are required. In operation, effective control over the generator’s acoustic emission is also necessary, and can be accomplished within the ECS system. Plug flow mufflers are commonly used, as they provide a sufficient level of noise attenuation in a compact structure. The key design parameter is the transmission loss of the muffler, as this dictates the level of attenuation at a given frequency. This work implements an analytically decoupled solution, using multiple perforate impedance models, through the transfer matrix method (TMM) to predict the transmission loss based on the muffler geometry. An equivalent finite element model is implemented for numerical simulation. The analytical results and numerical results are then evaluated against experimental data from literature.
2017-06-05
Technical Paper
2017-01-1798
Jiri Navratil, Warren Seeley, Peng Wang, Shriram Siravara
Abstract The ability to accurately predict exhaust system acoustics, including transmission loss (TL) and tailpipe noise, based on CAD geometry has long been a requirement of most OEM’s and Tier 1 exhaust suppliers. Correlation to measurement data has been problematic under various operating conditions, including flow. This study was undertaken to develop robust modelling technique, ensuring sensible correlation between the 1-D models and test data. Ford use Ricardo WAVE as one of their 1-D NVH tools, which was chosen for the purpose of this benchmark study. The most commonly used metrics for evaluating the acoustical performance of mufflers are insertion loss (IL), TL, and noise reduction (NR). TL is often the first step of analysis, since it represents the inherent capability of the muffler to attenuate sound if both the source and termination are assumed to be anechoic. It can also be reliably measured and numerically simulated without having to connect to an engine.
2017-03-28
Technical Paper
2017-01-1282
Ashish Jaiswal, Tarun Mehra, Monis Alam, Jatin Agarwal, Harshil Kathpalia
Abstract Dependency and increase in use of fossil fuels is leading to its depletion and raises serious environmental concerns. There are international obligations to reduce emissions and requirements to strengthen security of fuel supply which is pressuring the automobile industry to use cleaner and more sustainable fuels. Hydrogen fits these criteria as it is not just an abundant alternative but also a clean propellant and Hydrogen engines represent an economic alternative to fuel cells. In the present investigation, EGR has been used on hydrogen boosted SI engine running on gasoline-methanol and ethanol-gasoline blends to determine the additional advantages of the same compared to pure gasoline operation and gasoline-methanol and ethanol-gasoline blends without EGR.
2017-03-28
Technical Paper
2017-01-1444
Mitali Chakrabarti, Alfredo Perez Montiel, Israel Corrilo, Jing He, Angelo Patti, James Gebbie, Loren Lohmeyer, Bernd Dienhart, Klaus Schuermanns
CO2 is an alternative to replace the conventional refrigerant (R134a) for the air-conditioning system, due to the high Global Warming Potential (GWP) of R134a. There are concerns with the use of CO2 as a refrigerant due to health risks associated with exposure to CO2, if the concentration of CO2 is over the acceptable threshold. For applications with CO2 as the refrigerant, the risk of CO2 exposure is increased due to the possibility of CO2 leakage into the cabin through the duct system; this CO2 is in addition to the CO2 generated from the respiration of the occupants. The initiation of the leak could be due to a crash event or a malfunction of the refrigerant system. In an automobile, where the interior cabin is a closed volume (with minimal venting), the increase in concentration can be detrimental to the customer but is hard to detect.
2017-03-28
Technical Paper
2017-01-1320
Yucheng Liu
Abstract A cost effective, portable particulate management system was developed, prototyped, and evaluated for further application and commercialization, which could remove and dispose particulate matter suspended in air efficiently and safely. A prototype of the present system was built for experimental assessment and validation. The experimental data showed that the developed particulate management system can effectively clean the air by capturing the particles inside it. Effects of viscosity of filter medium on the performance of the developed system were also discussed. The present system is very flexible, whose size and shape can be scaled and changed to be fit for different applications. Its manufacturing cost is less than $10. Based on the experimental validation results, it was found that the present system can be further developed, commercialized, and applied for a variety of industries.
2017-03-28
Technical Paper
2017-01-1725
Tanawat Tessathan, Chutiphon Thammasiri, Prabhath De Silva, Rehan Hussain, Nuksit Noomwongs
Abstract It is common for users of commuting passenger cars in Thailand to use the vehicle’s HVAC (Heating, Ventilating and Air Conditioning) system predominantly in recirculation (REC) mode. This minimizes the compressor work, thereby saving fuel, and reduces dust and odor infiltration into the vehicle cabin. The car windows are rarely opened for ventilation purposes, except for exchanges at service stations such as garage entrances and tollway booths. As such, there are few opportunities for fresh air to enter the cabin with the consequent accumulation of CO2 in vehicle cabins due to occupants’ exhalations being well documented. Field experiments conducted showed that the in-vehicle CO2 concentrations could reach up to 15 times that of the ambient concentration level during typical city commutes. Preliminary experiments were also conducted to quantify the air exchanges between the cabin and the ambient when the doors are opened for occupant egression.
2017-03-28
Technical Paper
2017-01-0872
Sunil Kumar Pathak, Vineet sood, Yograj Singh, Shubham Gupta, Salim Abbasbhai Channiwala
Abstract In this study, A Gasoline Passenger car (Euro IV) was experimentally investigated for performance and emissions on three different fuels i.e. Gasoline, LPG (Liquefied Petroleum Gas) and DME (Di-methyl ether) blend with a concentration of 20% by mass in LPG (DME20). In particular, emission characteristics (including Hydrocarbon, CO, NOx, and CO2) over the Modified Indian Driving Cycle (MIDC) and fuel economy were investigated at the Vehicle Emission Laboratory (VEL) at the CSIR- Indian Institute of Petroleum, Dehradun, India. The experimental results showed that Vehicle complies with Euro IV legislation on gasoline and LPG fuel, however, showed higher NOx Emissions on DME 20 fuel. LPG kit was reconfigured for DME and LPG blend to bring down the emissions within the specified emission limits. The Emission values observed for DME20 were 0.635 g/km (CO), 0.044 g/km (THC), and 0.014 g/km (NOx) against the Euro IV limits of 1.0 g/km, 0.1 g/km and 0.08 g/km, respectively.
2017-03-28
Technical Paper
2017-01-0875
Valentin Soloiu, Jose Moncada, Martin Muinos, Aliyah Knowles, Remi Gaubert, Thomas Beyerl, Gustavo Molina
Abstract This paper investigates the performance of an indirect injection (IDI) diesel engine fueled with Bu25, 75% ultra-low sulfur diesel (ULSD#2) blended with 25% n-butanol by mass. N-butanol, derivable from biomass feedstock, was used given its availability as an alternative fuel that can supplement the existing limited fossil fuel supply. Combustion and emissions were investigated at 2000 rpm across loads of 4.3-7.2 bar indicated mean effective pressure (IMEP). Cylinder pressure was collected using Kistler piezoelectric transducers in the precombustion (PC) and main combustion (MC) chambers. Ignition delays ranged from 0.74 - 1.02 ms for both operated fuels. Even though n-butanol has a lower cetane number, the high swirl in the separate combustion chamber would help advance its premixed combustion. The heat release rate of Bu25 became initially 3 J/crank-angle-degree (CAD) higher than that of ULSD#2 as load increased to 7.2 bar IMEP.
2017-03-28
Technical Paper
2017-01-0957
Ian Smith, Thomas Briggs, Christopher Sharp, Cynthia Webb
Abstract It is projected that even when the entire on-road fleet of heavy-duty vehicles operating in California is compliant with 2010 emission standards of 0.20 g/bhp-hr, the National Ambient Air Quality Standards (NAAQS) requirements for ambient ozone will not be met. It is expected that further reductions in NOX emissions from the heavy-duty fleet will be required to achieve compliance with the ambient ozone requirement. To study the feasibility of further reductions, the California Air Resources Board (CARB) funded a research program to demonstrate the potential to reach 0.02 g/bhp-hr NOX emissions. This paper details the work executed to achieve this goal on the heavy-duty Federal Test Procedure (FTP) with a heavy-duty natural gas engine equipped with a three-way catalyst. A Cummins ISX-12G natural gas engine was modified and coupled with an advanced catalyst system.
2017-03-28
Technical Paper
2017-01-0580
Zainal Abidin, Kevin Hoag, Nicholas Badain
Abstract The promising D-EGR gasoline 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 gasoline engines as a lower cost replacement for medium duty diesel engines in trucks and construction equipment. However, medium duty diesel 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.
2017-03-28
Technical Paper
2017-01-0636
Vijai Shankar Bhavani Shankar, Nhut Lam, Arne Andersson, Bengt Johansson
Abstract The concept of double compression, and double expansion engine (DCEE) for improving the efficiency of piston reciprocating engines was introduced in SAE Paper 2015-01-1260. This engine configuration has separate high, and low pressure units thereby effectively reducing friction losses for high effective compression ratios. The presence of an additional expander stage also theoretically allows an extra degree of freedom to manipulate the combustion heat release rate so as to achieve better optimum between heat transfer, and friction losses. This paper presents a 1-D modeling study of the engine concept in GT-Power for assessing the sensitivity of engine losses to heat release rate. The simulations were constrained by limiting the maximum pressure to 300 bar.
2017-03-28
Technical Paper
2017-01-0638
Neerav Abani, Nishit Nagar, Rodrigo Zermeno, Michael chiang, Isaac Thomas
Abstract Heavy-duty vehicles, currently the second largest source of fuel consumption and carbon emissions are projected to be fastest growing mode in transportation sector in future. There is a clear need to increase fuel efficiency and lower emissions for these engines. The Opposed-Piston Engine (OP Engine) has the potential to address this growing need. In this paper, results are presented for a 9.8L three-cylinder two-stroke OP Engine that shows the potential of achieving 55% brake thermal efficiency (BTE), while simultaneously satisfying emission targets for tail pipe emissions. The two-stroke OP Engines are inherently more cost effective due to less engine parts. The OP Engine architecture presented in this paper can meet this performance without the use of waste heat recovery systems or turbo-compounding and hence is the most cost effective technology to deliver this level of fuel efficiency.
2017-03-28
Technical Paper
2017-01-0135
Jose Grande, Julio Abraham Carrera, Manuel Dieguez Sr
Abstract Exhaust Gas Recirculation (EGR) is an effective technique for reducing NOx emissions in order to achieve the ever more stringent emissions standards. This system is widely used in commercial vehicle engines in which thermal loads and durability are a critical issue. In addition, the development deadlines of the new engine generations are being considerably reduced, especially for validation test phase in which customers usually require robust parts for engine validation in the first stages of the project. Some of the most critical issues in this initial phases of program development are heavy boiling and thermal fatigue. Consequently it has been necessary to develop a procedure for designing EGR coolers that are sufficiently robust against heavy boiling and thermal fatigue in a short period of time, even when the engine calibration is not finished and the working conditions of the EGR system are not completely defined.
2017-03-28
Technical Paper
2017-01-0127
Norimitsu Matsudaira, Mitsuru Iwasaki, Junichiro Hara, Tomohiko Furuhata, Tatsuya Arai, Yasuo Moriyoshi, Naohiro Hasegawa
Abstract Among the emerging technologies in order to meet ever stringent emission and fuel consumption regulations, Exhaust Gas Recirculation (EGR) system is becoming one of the prerequisites particularly for diesel engines. Although EGR cooler is considered to be an effective measure for further performance enhancement, exhaust gas soot deposition may cause degradation of the cooling. To address this issue, the authors studied the visualization of the soot deposition and removal phenomena to understand its behavior. Based on thermophoresis theory, which indicates that the effect of thermophoresis depends on the temperature difference between the gas and the wall surface exposed to the gas, a visualization method using a heated glass window was developed. By using glass with the transparent conductive oxide: tin-doped indium oxide, temperature of the heated glass surface is raised.
2017-03-28
Technical Paper
2017-01-0524
Lei Liang, Huaqi Ge, Haiwen Ge, Peng Zhao
Abstract The thermal efficiency of spark-ignition engines can be enhanced by increasing the rate of exhaust gas recirculation (EGR) such that the low temperature combustion regime could be achieved. However, there is an upper limit on the amount of EGR rate, beyond which flame speed becomes slow and unstable, and local quenching starts to hurt the combustion stability, efficiency, and emission. To resolve this issue, the concept of dedicated EGR has been proposed previously to be an effective way to enhance flame propagation under lean burn condition with even higher levels of EGR with reformate hydrogen and carbon monoxide. In this study, the effects of thermochemical fuel reforming on the reformate composition under rich conditions (1.0 < ϕ < 2.0) have been studied using detailed chemistry for iso-octane, as the representative component for gasoline.
2017-03-28
Technical Paper
2017-01-0679
Kelvin Xie, Shui Yu, Xiao Yu, Geraint Bryden, Ming Zheng, Mengzhu Liu
Abstract In order to meet the future carbon dioxide legislation, advanced clean combustion engines are tending to employ low temperature diluted combustion strategies along with intensified cylinder charge motion. The diluted mixtures are made by means of excess air admission or exhaust gas recirculation. A slower combustion speed during the early flame kernel development because of the suppressed mixture reactivity will reduce the reliability of the ignition process and the overall combustion stability. In an effort to address this issue, an ignition strategy using a multi-pole spark igniter is tested in this work. The igniter uses three electrically independent spark gaps to allow three spatially distributed spark discharges. The multi-pole spark strategy displayed more advanced combustion phasing and lower phasing variability compared to single spark discharges.
2017-03-28
Technical Paper
2017-01-0702
Raouf Mobasheri, Mahdi Seddiq
Abstract The simultaneous effects of pilot fuel quantity and pilot injection timing on engine performance and amount of pollutant emission have been computationally investigated in a High Speed Direct Injection (HSDI) diesel engine. In this study, a modified parameter called “Homogeneity Factor of in-cylinder charge (HF)” has been applied to analyze the air-fuel mixing and combustion processes. For this purpose, the simulated results has been firstly compared with the experimental data and a good agreement has been achieved for simulating the in-cylinder pressure and the amount of pollutant emissions. Then, nine different strategies based on two variables (the amount of fuel mass in pilot and main injection as well as the dwell between two injections) have been investigated.
2017-03-28
Technical Paper
2017-01-0700
Valentin Soloiu, Aliyah Knowles, Jose Moncada, Emerald Simons, Martin Muinos, Thomas Beyerl
Abstract The Cottonseed biodiesel combustion, sound and vibrations have been evaluated in a medium duty single cylinder DI engine (1.1L/cyl) by comparison with s ULSD#2 reference values. The engine was supercharged and had 20% EGR and all tests were conducted at 1400 rpm and at 4 bar BMEP load. Cylinder pressure was determined using a Kistler piezoelectric transducer. Combustion pressures peaked at 76 bar for both fuels. Ignition delay for CS100 decreased by 0.16 ms when compared to the ULSD#2 baseline. This would lead to a 23% lower peak heat release rate when operating CS100. The pressure rise rate for CS100 was 20% lower than ULSD#2, which related to the reduced ringing intensity for the biodiesel. The sound and vibrations were measured using a B&K condenser type multi-field microphone, and a tri-axial, piezoelectric accelerometer. All noise & vibration signals were analyzed with CPB and FFT Analysis, and Crank Angle Domain Analysis with B&K Pulse Platform software.
2017-03-28
Technical Paper
2017-01-0721
Michele Bardi, Gilles Bruneaux, André Nicolle, Olivier Colin
Abstract This paper is a contribution to the understanding of the formation and oxidation of soot in Diesel combustion. An ECN spray A injector (single axial-oriented orifice) was tested in a well characterized high-temperature/high-pressure vessel at engine relevant conditions. The size of the test section (>70mm) enables to study the soot formation process in nearly free field conditions, which constitutes an ideal feature for fundamental understanding and model validation. Simultaneous high-speed OH* chemiluminescence imaging and high-speed 2D extinction were performed to link together the information regarding flame chemistry (i.e. lift-off length) and the soot data. The experiments were carried out for a set of fuels with different CN and sooting index (Diesel fuel, Jet fuel, gasoline and n-dodecane) performing parametric variations in the test conditions (ambient temperature and oxygen concentration).
2017-03-28
Technical Paper
2017-01-0707
Srinivas Padala, Minh Khoi Le, Yoshihiro Wachi, Yuji Ikeda
Abstract The effect of microwave enhanced plasma (MW Plasma) on diesel spray combustion was investigated inside a constant volume high pressure chamber. A microwave-enhanced plasma system, in which plasma discharge generated by a spark plug was amplified using microwave pulses, was used as plasma source. This plasma was introduced to the soot cloud after the occurrence of autoignition, downstream of the flame lift-off position to allow additional plasma-generated oxidizers to be entrained into the hot combustion products. Planar laser induced incandescence (PLII) diagnostics were performed with laser sheet formed from 532 nm Nd:YAG laser to estimate possible soot reduction effect of MW plasma. A semi-quantitative comparison was made between without-plasma conventional diesel combustion and with-plasma combustion; with LII performed at different jet cross-sections in the combustion chamber.
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
2017-01-1006
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
2017-01-0999
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
2017-01-0973
Naoko Uchiumi, Hiroshi Hirabayashi, Shinya Sato, Takafumi Yamauchi
Abstract Urea-SCR(selective catalytic reduction) system is widely used as a technology of NOx(Nitrogen Oxides) reduction from diesel engine exhaust gases. Emission regulations have becoming stricter all over the world, and high NOx reduction performance is necessary to meet the emission regulations. To get higher NOx reduction performance of the Urea-SCR system, it is important to understand detailed chemical reaction mechanisms of Urea-SCR catalysts. In this study, we focused on elucidation of the reaction mechanism of the Urea-SCR catalyst by numerical simulation approach. The chemical reaction models with detail chemical reactions were built for both Fe-catalyst and Cu-catalyst. Both of the catalytic reaction models can predict difference of the catalytic reaction performance between the Fe-catalyst and the Cu-catalyst. In addition, rate-determining reaction step of the Cu-catalyst was successfully identified by the numerical simulation results.
2017-03-28
Technical Paper
2017-01-0972
Jiri Figura, Jaroslav Pekar, Pavel Krejza, David Mracek, Dirk von Wissel, Tianran Zhang
Abstract Many control approaches for selective catalytic reduction (SCR) systems require knowledge of ammonia storage (NH3 storage) to dose urea accurately. Currently there are no technologies to directly measure internal NH3 storage in a vehicle, so it can only be inferred from hardware sensors located upstream, downstream, or in the catalyst. This paper describes an application of extended Kalman filter (EKF) state estimator used as a virtual sensor for urea injection control of a multi-brick aftertreatment system. The proposed estimator combines mean-value physics-based models of combined SCR and diesel particulate filter (SCR/DPF), SCR and clean-up catalyst (CUC). It uses hardware sensors at the inlet and outlet of the aftertreatment system, and includes no sensors between the catalysts. Performance of the proposed estimator was validated in simulations against a high-fidelity model of the aftertreatment system.
2017-03-28
Technical Paper
2017-01-0966
Jana Aslanjan, Christian Klauer, Cathleen Perlman, Vivien Günther, Fabian Mauss
Abstract The three-way catalytic converter (TWC) is the most common catalyst for gasoline engine exhaust gas after treatment. The reduction of carbon monoxide (CO), nitrogen oxides (NOx) and unburned hydrocarbons (HC) is achieved via oxidation of carbon monoxide and hydrocarbons, and reduction of nitrogen oxides. These conversion effects were simulated in previous works using single-channel approaches and detailed kinetic models. In addition to the single-channel model multiple representative catalyst channels are used in this work to take heat transfer between the channels into account. Furthermore, inlet temperature distribution is considered. Each channel is split into a user given number of cells and each cell is treated like a perfectly stirred reactor (PSR). The simulation is validated against an experimental four-stroke engine setup with emission outputs fed into a TWC.
2017-03-28
Technical Paper
2017-01-0683
Michael Fischer, Philipp Kreutziger, Yong Sun, Adam Kotrba
Abstract External Exhaust Gas Recirculation (EGR) has been used on diesel engines for decades and has also been used on gasoline engines in the past. It is recently reintroduced on gasoline engines to improve fuel economy at mid and high engine load conditions, where EGR can reduce throttling losses and fuel enrichment. Fuel enrichment causes fuel penalty and high soot particulates, as well as hydrocarbon (HC) emissions, all of which are limited by emissions regulations. Under stoichiometric conditions, gasoline engines can be operated at high EGR rates (> 20%), but more than diesel engines, its intake gas including external EGR needs extreme cooling (down to ~50°C) to gain the maximum fuel economy improvement. However, external EGR and its problems at low temperatures (fouling, corrosion & condensation) are well known.
2017-03-28
Technical Paper
2017-01-0684
Vickey B. Kalaskar, Raphael Gukelberger, Bradley Denton, Thomas Briggs
Abstract Dedicated EGR has shown promise for achieving high efficiency with low emissions [1]. For the present study, a 4-cylinder turbocharged GDI engine which was modified to a D-EGR configuration was used to investigate the impact of valve phasing and different injection strategies on the reformate production in the dedicated cylinder. Various levels of positive valve overlap were used in conjunction with different approaches for dedicated cylinder over fueling using PFI and DI fuel systems. Three speed-load combinations were studied, 2000 rpm 4 bar IMEPg, 2000 rpm 12 bar IMEPg, and 4000 rpm 12 bar IMEPg. The primary investigation was conducted to map out the dedicated cylinders' performance at the operating limits of intake and exhaust cam phasing. In this case, the limits were defined as conditions that yielded either no reformate benefit or led to instability in the dedicated cylinder.
Viewing 1 to 30 of 14987