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Viewing 241 to 270 of 16604
2017-03-28
Technical Paper
2017-01-0885
Bhuvenesh Tyagi, Vishnu Vijayakumar, Shyam Singh, Ajay Kumar Sehgal, R Suresh
Abstract Majority of light and heavy duty commercial vehicles on road in India use API-CF grade lubricants. Soot accumulation in lubricating oil can result in engine wear and lubricant’s viscosity increase thereby affecting its pumping ability and drain interval. Due to faster lubricant degradation and with emergence of newer engine technologies, there is increasing demand of improving performance of lubricants particularly with respect to soot dispersancy. This paper describes the various engine hardware modifications and optimizations carried out on a commercial BS II, 4-cylinder turbocharged diesel engine in order to develop a flexible engine test procedure for evaluating the lubricant’s dispersancy/anti wear characteristics up to 6% soot levels.
2017-03-28
Technical Paper
2017-01-0888
Prashant Kumar, Reji Mathai, Sanjeev KUMAR, Ashish Kachhawa, Ajay Kumar Sehgal, Snigdhamayee Praharaj
Abstract The growing transportation sector worldwide has opened up a way forward not only for the scientists & researchers but also for the OEMs to find out the options for fuel efficient automotive vehicles with reduced emissions during their usage. The demand of automotive vehicles has been doubled in last few years and in turn the market for lubricants and transmission fluids are flourishing. Several new formulations of lubricants are getting popularized with major suppliers to achieve the end user expectations in terms of fuel economy benefits, engine life and emissions. The market trend is continuously moving towards the improvement in lubricant formulation to the lower viscosity ranges and in this direction several companies are into development of multi-grade low viscosity range of engine oils (lubricants) which is said to be providing the benefits in terms of fuel economy.
2017-03-28
Technical Paper
2017-01-0890
Yoichiro Nakamura, Masahisa Horikoshi, Yasunori TAKEI, Takahiro Onishi, Yasuhiro Murakami, Chip Hewette
Abstract Heavy duty vehicles take a large role in providing global logistics. It is required to have both high durability and reduced CO2 from the viewpoint of global environment conservation. Therefore lubricating oils for transmission and axle/differential gear box are required to have excellent protection and longer drain intervals. However, it is also necessary that the gear oil maintain suitable friction performance for the synchronizers of the transmission. Even with such good performance, both transmission and axle/differential gear box lubricants must balance cost and performance, in particular in the Asian market. The development of gear oil additives for high reliability gear oil must consider the available base oils in various regions as the additive is a global product. In many cases general long drain gear oils for heavy duty vehicles use the group III or IV base oils, but it is desirable to use the group I/II base oils in terms of cost and availability.
2017-03-28
Technical Paper
2017-01-1232
Tsubasa Yamazakii, Hidekazu Uchiyama, Kazuaki Nakazawa, Tsubasa Isomura, Hisashi Ogata
Abstract Solar car races are held worldwide, aiming to promote vehicles that help reduce environmental loads on the roads. In order to gain superiority in solar car racing, it is essential to develop a high efficiency brushless direct drive motor that optimizes the energy use to the fullest and allows high speed driving when needed. To achieve these goals, two development approaches of solar car motors are proposed: the high efficiency motor which improves electrical characteristics and significantly reduces energy loss; and the variable field magnet motor that offers instant speed boost for a temporary period of time for overtaking opponents. We have developed a high efficiency motor through the application of an amorphous core and laminated magnets. Instead of the standard method of the W-EDM (Wire-Electric Discharge Machining) for amorphous cores, we utilized water jet cutting, through which we succeeded in achieving insulation between laminated cores.
2017-03-28
Technical Paper
2017-01-1233
Mohamed A. Elshaer, Allan Gale, Chingchi Chen
Abstract Vehicle safety is of paramount importance when it comes to plugging the vehicle into the electric utility grid. The impact of high voltage ground fault has been neglected or, if not, addressed by guidelines extracted from general practices, written in international standards. The agile accretion in Electric Vehicle (EV) development deems an exhaustive study on safety risks pertaining to fault occurrence. While vehicle electrification offers a vital solution to oil scarcity, it is essential that the fast development of the number of electric vehicles on the road does not compromise safety. Meanwhile, the link between technology and demands of society must be governed by vehicle safety. In this paper, a comprehensive study on high voltage (HV) fault conditions occurring in an EV will be conducted. In the next decade, EVs are expected to be prevalent worldwide. Ground fault characteristics are significantly dependent on the earthing system.
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
2017-01-1281
Rajesh Kumar, Olivier Laget, Guillaume Pilla, Guillaume Bourhis, Roland Dauphin, Loic de Francqueville, Jean-Pascal Solari
Abstract Reduction of CO2 emissions is becoming one of the great challenges for future gasoline engines. The aim of the current research program (OOD: Octane On Demand) is to use the octane number as a tuning parameter to simultaneously make the engine more efficient and reduce CO2 emissions. The idea is to prevent knock occurrence by adapting the fuel RON injected in the combustion chamber. Thus, the engine cycle efficiency is increased by keeping combustion phasing at its optimum. This is achieved by a dual fuel injection strategy, involving a low-RON base fuel (Naphtha or Low RON cost effective fuel) and a high-RON octane booster (ethanol). The ratio of fuel quantity on each injector is adapted at each engine cycle to fit the RON requirement as a function of engine operating conditions. A first part of the project, described in [18], was dedicated to the understanding of mixture preparation resulting from different dual-fuel injection strategies.
2017-03-28
Technical Paper
2017-01-1283
Valentin Soloiu, Remi Gaubert, Martin Muinos, Jose Moncada, Thomas Beyerl, Gustavo Molina, Johnnie Williams
Abstract This study investigates the use of a natural gas derived fuel, synthetic Fischer-Tropsch (F-T) paraffinic kerosene, in both it’s neat form and blended with ultra-low sulfur diesel (ULSD#2), in a naturally aspirated indirect injected engine. A blend of a mass ratio with 20% of the F-T fuel and 80% ULSD#2 was studied for its combustion characteristics, emissions, and efficiency compared to conventional ULSD#2 at a constant speed of 2400 RPM and operating at IMEP range from 4.5 to 6.5 bar. The F-T blend produced ignition delays 17% shorter than ULSD#2 resulting in slightly lower peak apparent heat release rates (AHRR) along with decreased peak combustion temperatures, by up to 50°C. Nitrogen Oxide (NOx) emissions of the F-T blend decreased by 4.0% at 4.5 bar IMEP and at negligible amounts at 6.5 bar IMEP. The F-T blend decreased soot significantly at 5.4 bar IMEP by 40%. Efficiencies of the F-T blend were similar to ULSD#2.
2017-03-28
Technical Paper
2017-01-1292
Saiful Bari, Idris Saad
Abstract Diesel engine can be run with biodiesel which has the potential to supplement the receding supply of crude oil. As biodiesel possess similar physiochemical properties to diesel, most diesel engines can run with biodiesel with minimum modifications. However, the viscosity of biodiesel is higher, and the calorific value is lower than diesel. Therefore, when biodiesel is used in diesel engines, it is usually blended with diesel at different proportions. Use of 100% biodiesel in diesel engines shows inferior performance of having lower power and torque. Improving in-cylinder airflow characteristic to break down higher viscous biodiesel and to improve air-fuel mixing are the aims of this research. Therefore, guide vanes in the intake runner were used in this research to improve the performance of diesel engine run with biodiesel.
2017-03-28
Technical Paper
2017-01-1285
Tarun Mehra
Abstract Exploring and enhancement of biodiesel production from feedstock like non-edible vegetable oil is one of the powerful method to resolve inadequate amount of conventional raw materials and their high prices. The main aim of this study is to optimize the biodiesel production process parameters of a biodiesel obtained from non-edible feedstocks, namely Neem (Azadirachta indica) oil and Sesame (Sesamum indicum L.) oil, with response surface methodology using Doehlert’s experimental design. Based on the results, the optimum operating parameters for transesterification of the mixture A50S50 oil mixture at 51.045° C over a period of 45 minutes are as follows: methanol-to-oil ratio: 8.45, and catalyst concentration: 1.933 wt.%. These optimum operating parameters give the highest yield for the A50S50 biodiesel with a value of 95.24%.
2017-03-28
Technical Paper
2017-01-1288
Noriko Shisa, Shinsuke Ishihara, Yougui Huang, Mikio Asai, Katsuhiko Ariga
Abstract Despite the fact that methanol is toxic to human health and causes serious damage to automobile engines and fuel system components, methanol-containing gasoline is becoming popular in some areas. Methanol demonstrates similar chemical properties to ethanol (which is already established as an additive to gasoline), so that it is difficult to identify methanol-containing gasoline without performing proper chemical analysis. In this study, we report a low-cost, portable, and easy-to-operate sensor that selectively changes color in response to methanol contained in gasoline. The colorimetric sensor will be useful for automobile users to avoid methanol-containing gasoline upon refueling.
2017-03-28
Technical Paper
2017-01-0519
Maziar Khosravi, Aadinath Harihar, Heinz Pitsch, Carsten Weber
Abstract The performance of modern boosted gasoline engines is limited at high loads by knock, stochastic Low Speed Pre-Ignition as well as megaknock. The main objective of the present work is to develop a predictive combustion model to investigate auto-ignition and megaknock events at high load conditions in gasoline engines. A quasi one-dimensional combustion simulation tool has been developed to model abnormal combustion events in gasoline engines using detailed chemical kinetics and a multi zone wall heat transfer model. The model features six boundary layers representing specific geometrical features such as liner and piston with individual wall temperatures and chemistry to accurately track the individual zone’s thermodynamic properties. The accuracy of the utilized auto-ignition and one-dimensional spark ignition combustion models was demonstrated by validating against experimental data.
2017-03-28
Technical Paper
2017-01-0538
Corinna Netzer, Lars Seidel, Michal Pasternak, Christian Klauer, Cathleen Perlman, Frederic Ravet, Fabian Mauss
Abstract Engine knock is an important phenomenon that needs consideration in the development of gasoline fueled engines. In our days, this development is supported by the use of numerical simulation tools to further understand and subsequently predict in-cylinder processes. In this work, a model tool chain based on detailed chemical and physical models is proposed to predict the auto-ignition behavior of fuels with different octane ratings and to evaluate the transition from harmless auto-ignitive deflagration to knocking combustion. In our method, the auto-ignition and emissions are calculated based on a new reaction scheme for mixtures of iso-octane, n-heptane, toluene and ethanol (Ethanol consisting Toluene Reference Fuel, ETRF). The reaction scheme is validated for a wide range of mixtures and every desired mixture of the four fuel components can be applied in the engine simulation.
2017-03-28
Technical Paper
2017-01-0539
Duc-Khanh Nguyen, Sebastian Verhelst
Abstract Methanol fueled spark ignition (SI) engines have the potential for very high efficiency using an advanced heat recovery system for fuel reforming. In order to allow simulation of such an engine system, several sub-models are needed. This paper reports the development of two laminar burning velocity correlations, corresponding to two reforming concepts, one in which the reformer uses water from an extra tank to produce hydrogen rich gas (syngas) and another that employs the water vapor in the exhaust gas recirculation (EGR) stream to produce reformed-EGR (R-EGR). This work uses a one-dimensional (1D) flame simulation tool with a comprehensive chemical kinetic mechanism to predict the laminar burning velocities of methanol/syngas blends and correlate it. The syngas is a mixture of H2/CO/CO2 with a CO selectivity of 6.5% to simulate the methanol steam reforming products over a Cu-Mn/Al catalyst.
2017-03-28
Technical Paper
2017-01-0532
Hoon Lee, Byungho Lee, Sejun Kim, Namdoo Kim, Aymeric Rousseau
Abstract Many leading companies in the automotive industry have been putting tremendous amount of efforts into developing new designs and technologies to make their products more energy efficient. It is straightforward to evaluate the fuel economy benefit of an individual technology in specific systems and components. However, when multiple technologies are combined and integrated into a whole vehicle, estimating the impact without building and testing an actual vehicle becomes very complex, because the efficiency gains from individual components do not simply add up. In an early concept phase, a projection of fuel efficiency benefits from new technologies will be extremely useful; but in many cases, the outlook has to rely on engineer’s insight since it is impractical to run tests for all possible technology combinations.
2017-03-28
Technical Paper
2017-01-0640
Robert Wade, Steven Murphy, Paul Cross, Craig Hansen
Abstract The Variable Displacement Supercharger (VDS) is a twin helical screw style compressor that has a feature to change its displacement and its compression ratio actively during vehicle operation. This device can reduce the parasitic losses associated with supercharging and improve the relative fuel economy of a supercharged engine. Supercharging is a boosting choice with several advantages over turbocharging. There is fast pressure delivery to the engine intake manifold for fast engine torque response providing the fun to drive feel. The performance delivered by a supercharger can enable engine fuel economy actions to include engine downsizing and downspeeding. The cost and difficulty of engineering hot exhaust components is eliminated when using only an air side compressor. Faster catalyst warm up can be achieved when not warming the turbine housing of a turbocharger.
2017-03-28
Technical Paper
2017-01-0588
Adithya P Reddy Ranga, Gopichandra Surnilla, Joseph Thomas, Ethan Sanborn, Mark Linenberg
Abstract Dual fuel injection systems, like PFI+DI (port fuel injection + direct injection system) are being increasingly used in gasoline engine applications to increase the engine performance, fuel efficiency and reduce emissions. At a given engine operating condition, the air/fuel error is a function of the fraction of fuel injected by each of the fuel systems. If the fraction of fuel from each of the fuel system is changed at a given operating condition, the fuel system error will change as well making it challenging to learn the fuel system errors. This paper aims at describing the adaptive fueling control algorithm to estimate the fuel error contribution from each individual fuel system. Considering the fuel injection system slope errors to be the significant cause for air-fuel errors, a model structure was developed to calculate the fuel system adaptive correction factor as a function of changing fraction of fueling between the fuel systems.
2017-03-28
Technical Paper
2017-01-0592
Robin Holmbom, Bohan Liang, Lars Eriksson
1 Turbocharging plays an important role in the downsizing of engines. Model-based approaches for boost control are going to increasing the necessity for controlling the wastegate flow more accurately. In today’s cars, the wastegate is usually only controlled with a duty cycle and without position feedback. Due to nonlinearities and varying disturbances a duty cycle does not correspond to a certain position. Currently the most frequently used feedback controller strategy is to use the boost pressure as the controller reference. This means that there is a large time constant from actuation command to effect in boost pressure, which can impair dynamic performance. In this paper, the performance of an electrically controlled vacuum-actuated waste-gate, subsequently referred to as vacuum wastegate, is compared to an electrical servo-controlled wastegate, also referred to as electric wastegate.
2017-03-28
Technical Paper
2017-01-0591
Andreas Thomasson, Xavier Llamas, Lars Eriksson
1 In modern turbocharged engines the power output is strongly connected to the turbocharger speed, through the flow characteristics of the turbocharger. Turbo speed is therefore an important state for the engine operation, but it is usually not measured or controlled directly. Still the control system must ensure that the turbo speed does not exceed its maximum allowed value to prevent damaging the turbocharger. Having access to a turbo speed signal, preferably by a cheap and reliable estimation instead of a sensor, could be beneficial for over speed protection and supervision of the turbocharger. This paper proposes a turbo speed observer that only utilizes the conditions around the compressor and a model for the compressor map. These conditions are either measured or can be more easily estimated from available sensors compared the conditions on the turbine side.
2017-03-28
Technical Paper
2017-01-0594
Baitao Xiao, Erik Hellstrom, Yan Wang, Julia Buckland, Mario Santillo
Abstract Turbocharger compressors are susceptible to surge – the instability phenomena that impose limitations on the operation of turbocharged engines because of undesired noise, engine torque capability constraints, and hardware strain. Turbocharged engines are typically equipped with a binary compressor recirculation valve (CRV) whose primary function is to prevent compressor surge. Calibration of the associated control strategy requires in-vehicle tests and usually employs subjective criteria. This work aims to reduce the calibration effort for the strategy by developing a test procedure and data processing algorithms. An automated calibration for CRV control is developed that will generate a baseline calibration that avoids surge events. The effort to obtain the baseline calibration, which can be further fine-tuned, is thereby significantly reduced.
2017-03-28
Technical Paper
2017-01-0593
Ivan Arsie, Rocco Di Leo, Cesare Pianese, Matteo De Cesare
Abstract The development of more affordable sensors together with the enhancement of computation features in current Engine Management Systems (EMS), makes the in-cylinder pressure sensing a suitable methodology for the on-board engine control and diagnosis. Since the 1960’s the in-cylinder pressure signal was employed to investigate the combustion process of the internal combustion engines for research purposes. Currently, the sensors cost reduction in addition to the need to comply with the strict emissions legislation has promoted a large-scale diffusion on production engines equipment. The in-cylinder pressure signal offers the opportunity to estimate with high dynamic response almost all the variables of interest for an effective engine combustion control even in case of non-conventional combustion processes (e.g. PCCI, HCCI, LTC).
2017-03-28
Technical Paper
2017-01-0817
Remi Konagaya, Ken Naitoh, Kohta TSURU, Yasuo Takagi, Yuji Mihara
Abstract For various densities of gas jets including very light hydrogen and relatively heavy ones, the penetration length and diffusion process of a single high-speed gas fuel jet injected into air are computed by performing a large eddy simulation (LES) with fewer arbitrary constants applied for the unsteady three-dimensional compressible Navier-Stokes equation. In contrast, traditional ensemble models such as the Reynolds-averaged Navier-Stokes (RANS) equation have several arbitrary constants for fitting purposes. The cubic-interpolated pseudo-particle (CIP) method is employed for discretizing the nonlinear terms. Computations of single-component nitrogen and hydrogen jets were done under initial conditions of a fuel tank pressure of gas fuel = 10 MPa and back pressure of air = 3.5 MPa, i.e., the pressure level inside the combustion chamber after piston compression in the engine.
2017-03-28
Technical Paper
2017-01-0811
John Williams, Heather D. Hamje, David J. Rickeard, Andreas Kolbeck, Kalle Lehto, Elena Rebesco, Walter Mirabella, Carole A. Bontoft, Maria Dolores Cardenas
Abstract Research Octane Number (RON) and Motor Octane Number (MON) are used to describe gasoline combustion which describe antiknock performance under different conditions. Recent literature suggests that MON is less important than RON in modern cars and a relaxation in the MON specification could improve vehicle performance. At the same time, for the same octane number change, increasing RON appears to provide more benefit to engine power and acceleration than reducing MON. Some workers have advocated the use of an octane index (OI) which incorporates both parameters instead of either RON or MON to give an indication of gasoline knock resistance. Previous Concawe work investigated the effect of RON and MON on the power and acceleration performance of two Euro 4 gasoline passenger cars during an especially-designed acceleration test cycle.
2017-03-28
Technical Paper
2017-01-0806
Genki Kikuchi, Masashi Miyagawa, Yoshiaki Yamamoto, Naruhiko Inayoshi
Abstract Exhaust Gas Recirculation (EGR) systems reduce exhaust emissions and improve fuel efficiency. Recently, the number of EGR system installed vehicles has been increasing, especially for gasoline engine systems. One of the major causes of decreasing EGR function is deposit accumulation on a gas passage. The deposit consists mainly of hydrocarbons which are degradation products of fuel, thus the amount of deposit seems to be strongly affected by fuel compositions. Unfortunately there are not as many studies on EGR deposits with gasoline fuel as there are with diesel fuel. In this study, the influence of gasoline fuel compositions, especially aromatics which are major components of EGR gas, on chemical structures of the deposit were investigated. To clarify the accumulation mechanism of EGR deposits, a thermal oxidative degradation test with an autoclave unit and an actual gasoline engine test were employed.
2017-03-28
Technical Paper
2017-01-0804
Mohannad Al-Khodaier, Vijai Shankar Bhavani Shankar, Muhammad Waqas, Nimal Naser, Mani Sarathy, Bengt Johansson
Abstract Increasing the anti-knock quality of gasoline fuels can enable higher efficiency in spark ignition engines. In this study, the blending anti-knock quality of dicyclopentadiene (DCPD), a by-product of ethylene production from naphtha cracking, with various gasoline fuels is explored. The blends were tested in an ignition quality tester (IQT) and a modified cooperative fuel research (CFR) engine operating under homogenous charge compression ignition (HCCI) and knock limited spark advance (KLSA) conditions. Due to current fuel regulations, ethanol is widely used as a gasoline blending component in many markets. In addition, ethanol is widely used as a fuel and literature verifying its performance. Moreover, because ethanol exhibits synergistic effects, the test results of DCPD-gasoline blends were compared to those of ethanol-gasoline blends. The experiments conducted in this work enabled the screening of DCPD auto-ignition characteristics across a range of combustion modes.
2017-03-28
Technical Paper
2017-01-0805
Jue Li, Tushar K. Bera, Michael Parkes, Timothy J. Jacobs
Abstract This paper investigates the effect of the cetane number (CN) of a diesel fuel on the energy balance between a light duty (1.9L) and medium duty (4.5L) diesel engine. The two engines have a similar stroke to bore (S/B) ratio, and all other control parameters including: geometric compression ratio, cylinder number, stroke, and combustion chamber, have been kept the same, meaning that only the displacement changes between the engine platforms. Two Coordinating Research Council (CRC) diesel fuels for advanced combustion engines (FACE) were studied. The two fuels were selected to have a similar distillation profile and aromatic content, but varying CN. The effects on the energy balance of the engines were considered at two operating conditions; a “low load” condition of 1500 rev/min (RPM) and nominally 1.88 bar brake mean effective pressure (BMEP), and a “medium load” condition of 1500 RPM and 5.65 BMEP.
2017-03-28
Technical Paper
2017-01-0803
Christiane Behrendt, Alastair Smith
Abstract Injector cleanliness is well characterised in the literature [1,2,3,4] as a key factor for maintained engine performance in modern diesel cars. Injector deposits have been shown to reduce injector flow capacity resulting in power loss under full load; however, deposit effects on fuel economy are less well characterised. A study was conducted with the aim of developing an understanding of the impact of diesel injector nozzle deposits on fuel economy. A series of tests were run using a previously published chassis dynamometer test method. The test method was designed to evaluate injector deposit effects on performance under driving conditions more representative of real world driving than the high intensity test cycle of the industry standard, CEC DW10B engine test, [1]. The efficacy of different additive levels in maintaining injector cleanliness and therefore power and fuel economy was compared in a light duty Euro 5 certified vehicle.
2017-03-28
Technical Paper
2017-01-0783
Hamid R. Rahai, Yong Lee, Najmeh rahimi, Komal Gada
Abstract The investigation has been divided into two parts. In part one, numerical investigations of the effect of humid air with different levels of humidity on gaseous emissions of a non-premixed combustion have been investigated. This part of the investigation was a feasibility study, focused on how different levels of humidity in the intake air affects the exhaust NO emission. Part two of the investigation was verification of the numerical results with a naturally aspirated engine with natural gas as the fuel. Here, we also investigated the impact of humid air intake on engine’s particulate matter (PM) emission. For the numerical investigations, the non-premixed combustion in a single cylinder was simulated using the presumed probability density function combustion model. Simulations were performed for dry as well as humid intake air for 0%, 15%, and 30% relative humidity (RH).
2017-03-28
Technical Paper
2017-01-0782
Qian xiong, Yasuo Moriyoshi, Koji Morikawa, Yasushi takahashi, Tatsuya Kuboyama, Toshio Yamada
Abstract To understand the mechanism of the combustion by torch flame jet in a gas engine with pre-chamber and also to obtain the strategy of improving thermal efficiency by optimizing the structure of pre-chamber including the diameter and number of orifices, the combustion process was investigated by three dimensional numerical simulations and experiments of a single cylinder natural gas engine. As a result, the configuration of orifices was found to affect the combustion performance strongly. With the same orifice diameter of 1.5mm, thermal efficiency with 7 orifices in pre-chamber was higher than that with 4 orifices in pre-chamber, mainly due to the reduction of heat loss by decreasing the impingement of torch flame on the cylinder linear. Better thermal efficiency was achieved in this case because the flame propagated area increases rapidly while the flame jets do not impinge on the cylinder wall intensively.
2017-03-28
Technical Paper
2017-01-0781
Philip Zoldak, Jeffrey Naber
Abstract The increased availability of natural gas (NG) in the United States (US) and its relatively low cost versus diesel fuel has increased interest in the conversion of medium duty (MD) and heavy duty (HD) engines to NG fueled combustion systems. The aim for development for these NG engines is to realize fuel cost savings and increase operating range while reduce harmful emissions and maintaining durability. Traditionally, port-fuel injection (PFI) or premixed NG spark-ignited (SI) combustion systems have been used for light duty LD, and MD engines with widespread use in the US and Europe [1]. However, this technology exhibits poor thermal efficiency and is load limited due to knock phenomenon that has prohibited its use for HD engines. Spark Ignited Direct Injection (SIDI) can be used to create a partially stratified combustion (PSC) mixture of NG and air during the compression stroke.
Viewing 241 to 270 of 16604