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Technical Paper

Heat Loss Analysis for Various Piston Geometries in a Heavy-Duty Methanol PPC Engine.

2018-09-10
2018-01-1726
Partially premixed combustion (PPC) in internal combustion engine as a low temperature combustion strategy has shown great potential to achieve high thermodynamic efficiency. Methanol due to its unique properties is considered as a preferable PPC engine fuel. Methanol injection has a longer penetration length than gasoline fuel under the same operation condition, and as such typical injection timing and piston bowl geometry optimised for gasoline PPC engine is not suitable for methanol PPC engine. In this study a baseline methanol PPC experimental engine is consider with a single injection of methanol at close to TDC condition. CFD simulation is performed to simulate the baseline case and satisfactory results are obtained in terms of combustion phasing, incylinder pressure and heat release rate.
Technical Paper

Comparison of Accelerated Ash Loading Methods for Gasoline Particulate Filters

2018-09-10
2018-01-1703
Recent legislation enacted for the European Union (EU) and the United States calls for a substantial reduction in particulate mass (and number in the EU) emissions from gasoline spark-ignited vehicles. The most prominent technology being evaluated to reduce particulate emissions from a gasoline vehicle is a wall flow filter known as a gasoline particulate filter (GPF). Similar in nature to a diesel particulate filter (DPF), the GPF will trap and store particulate emissions from the engine, and oxidize said particulate with frequent regeneration events. The GPF will also collect ash particles in the wall flow substrate, which are metallic components that cannot be oxidized into gaseous components. Due to high temperature operation and frequent regeneration of the GPF, the impact of ash on the GPF has the potential to be substantially different from the impact of ash on the DPF.
Technical Paper

Predicting the Influences of Intake Port Geometry on the Tumble Generation and Turbulence Characteristics by Zero-Dimensional Spark Ignition Engine Model

2018-09-10
2018-01-1660
The flame propagation characteristic is one of the greatest factor that determines the performance of spark ignition (SI) engines. The in-cylinder flow dynamics is very significant in terms of flame propagation because of its direct influence on the flame shape, turbulent flame speed, and the ignition quality. A number of different techniques are available to optimize the in-cylinder flow and maximize the utilization of turbulence for faster combustion, and tumble enhancement by intake port geometry is one of them. Evaluating multiple designs under wide range of operating conditions by 3D-CFD requires excessive computational expenses, therefore, a low-dimensional model would be more competitive in such design optimization process. This work suggests a new modification approach for typical 0D turbulence model to account for the tumble generation during the intake process as well as the turbulence characteristics associated with it.
Technical Paper

Laminar Burning Velocity of Market Type Gasoline Surrogates as a Performance Indicator in Internal Combustion Engines

2018-09-10
2018-01-1667
The laminar burning velocity is an important parameter in various combustion models for engine simulations. With respect to computational time for computational fluid dynamics (CFD) and full system engine simulations, the calculation of laminar burning velocities using a detailed chemical mechanism can be replaced by incorporation of approximation formulas, based on rate-ratio asymptotics. In the present study, a work flow is developed to analyze the engine efficiency performance of spark ignition engines with respect to the laminar burning velocity as a fundamental fuel property. Firstly, methane is used as a fuel to assess practicability of the approach. The procedure is subsequently adopted for market type gasoline surrogates, RON95 and RON100. Detailed chemistry calculations are carried out for the three target fuels using existing state of the art mechanisms, the Aramco [Zhou et al., Proc. Combust. Inst., pp. 403-411, 2017] and the ITV RWTH mechanism [Cai et al., Combust.
Technical Paper

Investigation of a Cylinder Activation Concept for a Turbocharged Direct-Injection Gasoline Engine

2018-09-10
2018-01-1713
Today, downsizing through active displacement control is in series production using cylinder deactivation concepts. However, current systems deactivating two cylinders of a four-cylinder engine are limited regarding the effective CO2 saving potential due to the confined usable operating range of the two-cylinder mode. Therefore, the objective of the current investigation is a three-cylinder engine with the possibility to activate an additional (fourth) cylinder. For this purpose, a four-cylinder series engine was modified to the firing order of a three-cylinder engine for the first three cylinders. The exterior cylinders 1 and 4 are operated in parallel, with the fourth cylinder deactivated in efficiency mode. Launching and idle mode are also operated with three active cylinders. Additional modifications to the valve train were carried out in order to further exploit the increased residual gas tolerance due to the load point shift.
Technical Paper

The Effect of Cerium Oxide Nano Particles Fuel Additive on Performance and Emission of Karanja Biodiesel Fueled Compression Ignition Military 585kW Heavy Duty Diesel Engine

2018-09-10
2018-01-1818
Global warming with stringent emission legislation along with the depletion of fossil fuel has given us an opportunity to find biodiesel as alternative to diesel fuel. Biodiesel has been widely accepted as comparable fuel to diesel in diesel engine. This is due to its renewable property, better lubricity, along with lesser gaseous emission as compared to diesel fuel. However, there is a major disadvantage in the use of biodiesel as it increases NOx emission. Fuel additive becomes one of the essential tools to overcome the drawback of biodiesel required to meet the international standard of performance and emission. In this study, the performance, combustion, and gaseous emission of CO, CO2, UBHC, NOx and PM including particle size number distribution characteristics, were compared for diesel, Karanja oil biodiesel, and Karanja oil biodiesel with Cerium Oxide Nano particles fuel additive, in a 12 cylinder, 585 kW, CIDI military diesel engine.
Technical Paper

Effect of Piston Geometries on the Stratification Formation in the Transition from HCCI to PPC

2018-09-10
2018-01-1800
Partially premixed combustion (PPC) is an advanced combustion strategy which has been proposed to gain higher efficiency and lower emissions than conventional compression ignition, as well as more controllability compared to homogeneous charge compression ignition (HCCI). Stratification of the fuel-air mixture is the key reason achieving these benefits. Injection strategy, injector-piston geometry design, and fuel properties are common methods to manipulate the stratification level. In the author’s previous research, the effect of injection strategy and fuel properties on the stratification formation process were investigated. The results revealed that for a direct injection compression ignition engine, by changing the injection timing from -180˚ aTDC to around -20˚ aTDC, the combustion status experienced three different stages: the HCCI stage, transition stage, and PPC stage. It was found that within the transition stage, both efficiency and emissions deteriorated.
Technical Paper

Crank-angle resolved exergy analysis of Ethanol fuelled HCCI engine using newly reduced ethanol oxidation mechanism

2018-09-10
2018-01-1683
Ethanol fuelled homogenous charge compression ignition engine (HCCI) offers a better alternative to tackle the problems of achieving higher engine efficiency and lower emissions. Numerical simulations were carried out for a HCCI Engine fuelled with Ethanol by stochastic reactor model using newly reduced ethanol oxidation mechanism consists of 47 species and 272 reactions. Reduced mechanism used in the study is validated by measured engine cylinder pressure curves and measured ignition delays in constant volume reactors in previous study. Simulations are conducted for engine speeds ranging from 1000 to 3000 rpm at different intake temperatures (range 365-465 K) by varying air-fuel ratio. Parametric study of combustion and emission characteristics is conducted and engine maps are developed at most efficient inlet temperatures. HCCI operating range is defined using combustion efficiency (>85%) and maximum pressure rise rate (<5 MPa/ms).
Technical Paper

Development of Drive Cycles and Measurement of Fuel Economies of Light Duty Vehicles in Metro Manila

2018-09-10
2018-01-1758
The urban drive cycles for five different light duty vehicles (LDV) are developed in this study. Furthermore, the fuel consumption factors for each of the type of LDV are estimated. The study presents the methodology in the development of the drive cycles in which the speed profile of the specific type of vehicle is surveyed, downloaded and processed. In the survey of speed data, a Global Positioning System (GPS) device is used as an on-board instrument. The GPS device is placed on the dashboard of every surveyed vehicle and it recorded instantaneous speed in its memory. The speed data is downloaded from the device using software provided by the maker of the device (Garmin) called Mapsource. The speed data is processed using a program to execute the methodology in generating candidate drive cycles. The program creates drive cycles by randomly appending microtrips to form a minimum of twenty minute speed time profile.
Technical Paper

Kinetic measurements of HNCO hydrolysis over SCR catalyst

2018-09-10
2018-01-1764
To meet the strict emissions regulations for diesel engines, an advanced processing device such as a Urea-SCR (selective catalytic reduction) system is used to reduce NOx emissions. The Real Driving Emissions (RDE) test, which is implemented in the European Union, will expand the range of conditions under which the engine has to operate, which will lead to the construction of a Urea-SCR system capable of reducing NOx emissions at lower and higher temperature conditions, and at higher space velocity conditions than existing systems. Simulations are useful in improving the performance of the Urea-SCR system. However, it is necessary to construct a reliable NOx reduction model to use for system design, which covers the expanded engine operation conditions. In the Urea-SCR system, the mechanism of ammonia (NH3) formation from injected aqueous urea solution is not clear. Thus, it is important to clarify this mechanism to improve the NOx reduction model.
Technical Paper

Experimental Investigation on the Stabilizing Effect of n-Butanol on Diesel-Bioethanol Blends

2018-09-10
2018-01-1744
The current environmental policy of the European Union aims that, by 2020, 10% of the transport fuel of every country comes from renewable sources such as biofuels. One of the most popular biofuels, (bio)ethanol is a probable suitable candidate for addition in diesel fuel because of its cleaner combustion and the ability to reduce emissions of gaseous pollutants. However, its use presents some important problems, mainly because of its incompatibility with diesel fuel during mixing, due to the difference in the polarity. For this reason, substances that act as stabilizers of these mixtures are used and one of the most suitable is butanol. This substance is compatible with fuel and ethanol, acting as a chemical bridge between the two, but also exhibits positive combustion behavior, as it is also an oxygenate that can be produced from renewable sources as well. The aim of this work was to investigate the behavior of diesel-ethanol mixtures using butanol as co-solvent.
Technical Paper

Effects of bio-alcohol fuel blends on the aging of engine lubricating oil

2018-09-10
2018-01-1746
Alternative fuels and fuel blends of bio-alcohol will gain in importance for future mobility. The driving force is the necessary reduction of greenhouse gases and harmful exhaust gas components. The new fuels offer advantages in engine combustion and resulting exhaust emissions because of the short-chained molecules and resulting low C/H ratio, a higher oxygen content and a higher enthalpy of vaporization. The aim of the project is a systematic analysis and evaluation of the effects of two bio-alcohol blends on the lubrication oil ageing of a gasoline-driven EU6 passenger car engine. For this reason a test engine was operated with three different fuels: a premium fossil gasoline (RON 100) without a bio-alcohol component (reference fuel), a blend containing 30-v/v-ethanol (E30) and a blend containing 15-v/v-methanol (M15). Within engine tests blow-by gas and gas of the cylinder charge were sampled and condensed via cold traps for different engine operation points.
Technical Paper

Effects of soot deposition on NOx purification reaction and mass transfer in SCR/DPF catalyst

2018-09-10
2018-01-1707
Experimental studies were carried out to investigate the effect of soot deposition on NOx purification phenomena in an ammonia SCR (Selective Catalytic Reduction) coated DPF (Diesel Particulate Filter) catalyst (SCR/DPF). In order to study soot deposition effects from both chemical reactions and mass transfer points of view, two types of testing devices were introduced. First, synthetic gas bench which can conduct the test considering temperature and flowrate ranges of 'real driving emissions' was used to investigate the soot influences on DeNOx characteristics under the real usage condition. Next, we have developed a micro-reactor in order to remove the effect of soot deposition on mass transfer in the catalyst layer and analyzed chemical reactions on soot surfaces and their interaction with the SCR catalyst. A test brick of Cu-zeolite SCR/DPF catalyst and a powder catalyst were used for each testing devices respectively, and engine soot was sampled to be used for all of tests.
Technical Paper

The effect of pressure, temperature and additives on droplet ignition of lubricant oil and its surrogate.

2018-09-10
2018-01-1673
Several studies demonstrated that the auto-ignition of lubricant oil droplet is considered one of the causes of pre-ignition event in a boosted DISI engine. Direct injection of fuel leads to impingement of fuel spray on the cylinder walls, causing dilution of oil on the liner, and subsequent ejection of fuel-oil mixture droplets into the combustion chamber. Therefore, it is important to understand the reactivity of lubricant oil in engine-like conditions. A constant volume (4 Liters) combustion chamber that allows introduction of a single droplet of lubricating oil has been built. It is capable of operation at elevated pressures and temperatures. In order to simulate the droplet-induced pre-ignition event, a droplet injection system is incorporated in the vessel. The oil delivery system is driven by a syringe pump. The oil droplet was suspended on the junction of a thermocouple where the instantaneous droplet temperature was measured throughout the oil droplet lifetime.
Technical Paper

Characterization of Hydroprocessed Used Cooking Oils as High Cetane Number Blending Component for Automotive Diesel

2018-09-10
2018-01-1745
Renewable substitutes for transportation fuels have an important role in the recent years. Hydrotreated vegetable oils (HVO) are produced from two stage hydrotreating process, mainly from vegetable oils. The second stage of this hydroteating process is used to convert normal paraffins to isoparaffins in order to improve cold flow properties of these fuels. As this stage is a high energy consuming process, it is of interest to investigate the characteristics and the usability of the first stage of hydroptreatment of lipids. This paper examines the properties of alternative fuel that derived from the hydrotreatment of used cooking oil (UCO). Used cooking oil is a difficult feedstock for biodiesel production. The hydrotreating of WCO converts triglycerides mainly into normal paraffins in the diesel fuel range. The hydrotreated UCO (HUCO) has an excellent cetane number and cetane index (>90), but has very poor cold flow properties.
Technical Paper

Numerical Investigation on Effects of Oxygen - enriched Air and Intake Air Humidification on Combustion and Emissions Characteristics of Marine Diesel Engines

2018-09-10
2018-01-1788
In order to meet the increasingly stringent emissions restriction , it is indispensable to improve the combustion and emissions of high-speed marine diesel engines. Oxygen-enriched combustion and intake air humidification are effective way to controlling pollution and improving combustion for diesel engines. In this study ,the combustion and emission characteristics of supercharged intercooled marine diesel engine with humidification rate and intake oxygen concentration were investigated by using multi-dimensional CFD model.The combustion model was established by AVL Fire code. The combination strategy of intake air humidification and oxygen - enriched combustion was optimized under partial load at 1350 r / min.
Technical Paper

A physical-based approach for modeling the influence of different operating parameters on the dependency of external EGR-rate and indicated efficiency.

2018-09-10
2018-01-1736
External Exhaust Gas Recirculation (EGR) provides an opportunity to increase the efficiency of turbocharged Spark-Ignition Engines. Among the competing technologies and configurations, Low Pressure EGR (LP-EGR) is most challenging regarding its dynamic behavior. Only a part of the stationary feasible potential can be used during dynamic engine operation. This is due to two reasons. One is the inhomogeneous distribution of optimized EGR-rate and EGR-tolerance over the engine load with low values at low loads and vice versa. The other reason is the volume between the EGR valve and the inlet valves. It is large for the configuration with exhaust gas supply in front of the compressor, as it is the case for LP-EGR. Both circumstances are particularly critical during engine load changes. The load changes can be highly dynamic so that time span between EGR valve adjustment and change of the EGR-rate at the inlet valves is comparatively long.
Technical Paper

Experimental Investigation of the effect of Karanja oil biodiesel with cerium oxide Nano particle fuel additive on lubricating oil tribology and engine wear in a heavy duty 38.8L,780 HP Military CIDI diesel engine.

2018-09-10
2018-01-1753
Biodiesel fuels are an alternative to diesel fuel. Biodiesel is an oxygenated, sulphur free, non-toxic, biogradable and renewable fuel. It is derived from vegetable oils. Since straight vegetable oils have quite high viscosity compared to mineral diesel, they have to be modified to bring their combustion-related properties and viscosity closer to mineral diesel. This is done by modifying their molecular structure through a transesterification process. In the present study, a military heavy duty 38.8 liter, 585kW supercharged, compression ignition diesel injection (CIDI) engine was fuelled with diesel, Karanja oil methyl ester (KOME) biodiesel, and KOME biodiesel with cerium oxide fuel additive, respectively. These were subjected to 100 hours long term endurance tests. Lubricating oil samples, drawn from the engine fuelled with these fuels, after a fixed interval of 20 hours, were subjected to elemental analysis.
Technical Paper

Compression ignition of low octane gasoline under partially premixed combustion modes

2018-09-10
2018-01-1797
Partially premixed combustion, PPC, is an operating range between the conventional compression Ignition, CI, and homogeneous charge compression ignition, HCCI. The combustion in this mixed mode is complex as it is not a diffusion controlled flame as in the CI engine and not the bulk auto-ignition of HCCI. In order to better understand the PPC combustion, the in-cylinder combustion process was captured and a combustion stratification index was derived to evaluate the level of combustion homogeneity. In addition, CFD simulations were performed and a flame index was derived to distinguish between zones having a premixed flame and zones with diffusion flame. The engine was operated with close to CI combustion with rather late fuel injection timing, 20 CAD BTDC and also with an earlier, 40 CAD BTDC, to get a more premixed type of combustion. In order to validate the simulations, optical engine experiments were conducted.
Technical Paper

Combined Fuel and Lubricant Effects on Low Speed Pre-Ignition

2018-09-10
2018-01-1669
Many studies on low speed pre-ignition have been published to investigate the impact of fuel properties and of lubricant properties. In general the results have shown that oil additives such as calcium sulfonate tend to increase the occurrence of LSPI while others such as magnesium sulfonate tend to decrease the occurrence. Likewise, fuels with high aromatic content have shown increased LSPI activity, as have fuels with higher distillation temperatures in the T70-100 range. One limitation of these studies is that they tend to use a reference fluid for either the oil or the fuel while the other is varied. In many cases the reference fluid is one which exhibits a moderate LSPI activity. This approach is useful in isolating only the impact of the oil or the fuel, but of course both fluids impact the LSPI behavior of the engine simultaneously.
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