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2014-11-11
Technical Paper
2014-32-0086
Yasufumi Yoshimoto, Eiji Kinoshita, Kazuyo Fushimi, Masayuki Yamada
Abstract This paper describes the influence of different kinds of FAME (fatty acid methyl ester) on the smoke emissions of a small single cylinder DI diesel engine and the soot formation characteristics in suspended single droplet combustion. The study used eight kinds of commercial FAME and diesel fuel blends. The tested FAMEs are saturated fatty acids with 8 to 18 carbon molecule chains, and with three different double bonds with C18. The results show that with all the FAME mixtures here, the brake thermal efficiencies with the FAME-diesel fuel blends were similar to neat diesel fuel operation while the smoke emissions with all of the tested FAME-diesel fuel blends were lower. To examine the differences in the soot formation characteristics, measurements of the formed soot mass were also performed with a basic experimental technique with suspended single droplet combustion. The soot was trapped on a glass fiber filter, and the mass of the filter was measured with an electronic microbalance.
2014-11-11
Technical Paper
2014-32-0090
Jeffrey Blair, Glenn Bower
Abstract Operation of snowmobiles in national parks is restricted to vehicles meeting the Best Available Technology standard for exhaust and noise emissions as established by the National Parks Service. An engine exceeding these standards while operating on a blend of gasoline and bio-isobutanol has been developed based on a production four-stroke snowmobile engine. Miller cycle operation was achieved via late intake valve closing and turbocharging. The production Rotax ACE 600cc 2 cylinder engine was modeled using Ricardo WAVE. After this model was validated with physical testing, different valve lift profiles were evaluated for brake specific fuel consumption and brake power. The results from this analysis were used to determine a camshaft profile for Miller cycle operation. This was done to reduce part load pumping losses and increase engine efficiency while maintaining production power density. A catalytic converter was added to reduce exhaust gas emissions, as measured by the EPA 40 CFR Part 1051 5-mode emissions test cycle.
2014-11-11
Technical Paper
2014-32-0004
Yuma Ishizawa, Munehiro Matsuishi, Yasuhide Abe, Go Emori, Akira Iijima, Hideo Shoji, Kazuhito Misawa, Hiraku Kojima, Kenjiro Nakama
Abstract One issue of Homogeneous Charge Compression Ignition (HCCI) engines that should be addressed is to suppress rapid combustion in the high-load region. Supercharging the intake air so as to form a leaner mixture is one way of moderating HCCI combustion. However, the specific effect of supercharging on moderating HCCI combustion and the mechanism involved are not fully understood yet. Therefore, experiments were conducted in this study that were designed to moderate rapid combustion in a test HCCI engine by supercharging the air inducted into the cylinder. The engine was operated under high-load levels in a supercharged state in order to make clear the effect of supercharging on expanding the stable operating region in the high-load range. HCCI combustion was investigated under these conditions by making in-cylinder spectroscopic measurements and by analyzing the exhaust gas using Fourier transform infrared (FT-IR) spectroscopy. The results revealed that cool flame reactions were induced by increasing boost pressure when gasoline with a Research Octane Number of approximately 91 was used as the test fuel.
2014-11-11
Technical Paper
2014-32-0102
Patrick Pertl, Philipp Zojer, Michael Lang, Oliver Schoegl, Alexander Trattner, Stephan Schmidt, Roland Kirchberger, Nagesh Mavinahally, Vinayaka Mavinahalli
Abstract The automotive industry has made great efforts in reducing fuel consumption. The efficiency of modern spark ignition (SI) engines has been increased by improving the combustion process and reducing engine losses such as friction, gas exchange and wall heat losses. Nevertheless, further efficiency improvement is indispensable for the reduction of CO2 emissions and the smart usage of available energy. In the previous years the Atkinson Cycle, realized over the crank train and/or valve train, is attracting considerable interest of several OEMs due to the high theoretical efficiency potential. In this publication a crank train-based Atkinson cycle engine is investigated. The researched engine, a 4-stroke 2 cylinder V-engine, basically consists of a special crank train linkage system and a novel Mono-Shaft valve train concept. The idea of a Mono-Shaft valve train mechanism is to realize the valve actuation without the need for separate cam shafts and gears, but via a cam disk rotating with crankshaft speed, thus enabling the integration of the cam disk in the crankshaft.
2014-11-11
Technical Paper
2014-32-0014
Hans-Juergen Schacht, Manuel Leibetseder, Niko Bretterklieber, Stephan Schmidt, Roland Kirchberger
Abstract Due to the small number of two wheelers in Europe and their seasonal use, their contribution to the total emissions has been underestimated for a long time. With the implementation of the new emission regulation 168/2013 [3] for type approval coming into force 2016, the two wheeler sector is facing major changes. The need to fulfil more stringent emission limits and the high demand on the durability of after treatment systems result in an engine control system that is getting more complex and therewith more expensive. Especially the low cost two wheelers with small engine capacities will be affected by increasing costs which cannot be covered by the actual competitive product price. Therefore, new vehicle concepts have to be introduced on the market. A vehicle concept of a plug in hybrid electric city scooter with range extender as well as the range extender itself have already been published in SAE Papers 2011-32-0592 [1] and 2012-32-0083 [2]. The low cost range extender is composed of a simple, throttle-less operated, port controlled two stroke engine and an externally controlled generator.
2014-11-11
Technical Paper
2014-32-0130
Takashi Onishi, Tomoya Akitomo, Yuichi Tamaki, Yoshikazu Takemoto, Hideyuki Goto, Mitsugu Okuda
Abstract All of non-road diesel engines over 19 kW in North America are required to reduce further Nitrogen Oxides (NOx) and Particulate Matter (PM) to meet US EPA emissions regulation. Especially, it is necessary to reduce PM emission up to one-tenth as conventional. In addition to improve combustion in engine, it is needed to add exhaust gas after-treatment device to reduce PM emission. It is necessary for diesel engine with exhaust gas after-treatment device, to have Diesel Particulate Filter (DPF) regeneration system, which burns periodically PM in DPF. Generally, DPF regeneration is implemented by using post injection with common rail system. However, post injection is not available in small diesel engine which has mechanical injection system and IDI combustion system instead of common rail system. As an alternative way, an original fuel reformer technique is introduced for DPF regeneration. Fuel reformer is located in the upper exhaust gas flow of DPF, and works independently from fuel injection system of engine.
2014-11-11
Technical Paper
2014-32-0029
Marcus Bonifer, Rainer Kiemel
Abstract Current catalytic formulations for motorcycles consist of so called three way catalysts (TWC) that are able to reduce the emissions of carbon monoxide (CO), nitrous oxides (NOx) and hydrocarbons (THC) below the regulatory emission limit. These catalysts mostly contain platinum (Pt), palladium (Pd) and rhodium (Rh), also called platinum group metals (PGM) in different ratios and concentrations. Another important component is the so-called oxygen storage material (OSC) that is compensating fluctuations in lambda during acceleration and deceleration. Currently existing catalyst formulations must be modified to fulfill the more stringent emission limits with simultaneous consideration of a more realistic test cycle. In this paper we will present the modification of an existing catalytic formulation for a 690 cm3 motorcycle from model year 2012. The motorcycle is equipped with a quick-change muffler to be able to compare different formulations in a simple way. The motorcycle was used off-shelf, during our tests no modifications of the ECU or the engine mapping haven taken place.
2014-11-11
Technical Paper
2014-32-0031
Juergen Tromayer, Gerd Neumann, Marcus Bonifer, Rainer Kiemel
Abstract Looking at upcoming emission legislations for two-wheelers, it is quite obvious that the fulfilment of these targets will become one of the biggest challenges within the engine development process. The gradual harmonization of emission limits for two-wheelers with existing automotive standards will subsequently lead to new approaches regarding mixture preparation and exhaust gas aftertreatment. Referring to these future scenarios, a state-of-the-art in development of catalytic converters for two- or three-wheeler applications should be presented. After choosing a suitable test carrier, which has already been equipped with EFI components including an oxygen sensor for λ=1 operation mode, a basic injection system calibration was used to optimize the combustion process. Based on this setup, a variable exhaust system was manufactured to be able to integrate different catalyst configurations. To improve cold start characteristics, the position of the lambda probe and the catalyst were optimized to achieve short light-off times.
2014-11-11
Technical Paper
2014-32-0032
Luiz Carlos Daemme, Renato Penteado, Fatima Zotin, Marcelo Errera
Abstract Motorcycle sales have increased consistently during the last decade mostly in developing countries, especially in the BRICS. Low cost and less fuel consumption comparing to cars associated to the economic growth are the main reason for such trend. Emission limits have become stricter and the use of gas after treatment devices is widely present in new models. Flex fuel motorcycles have now become available, but effects of the combination of diverse gasoline/ethanol blends on the emissions are still an open issue that requires further understanding. This paper presents the most recent results regarding regulated and unregulated emissions from a Flex Fuel motorcycle fuelled with 4 different gasoline/ethanol blends: E22, E61, E85 and 100% ethanol. Both regulated (CO, THC, NOx) and unregulated emissions (Aldehydes, NMHC, NH3, N2O) were studied. The main conclusion is that motorcycles equipped with three-way catalytic converters presented significant ammonia emissions in the tailpipe when compared to pre catalyst emissions.
2014-11-11
Technical Paper
2014-32-0035
Sayaka Yasoshina, Ryo Saito
Abstract Environmental problems such as air pollution have recently led to increasingly demanding emissions regulations. To address this issue, the present study aims to develop a technology that will enable the exhaust gas from compact generators, with output of less than 3 kVA, to satisfy the world's most demanding emissions regulations. The method we used is driven by pulsed secondary air injection with a catalyst. Whereas pump-driven methods have conventionally been the mainstream approach to attaining sufficient secondary air quantity to reduce emissions, our objective was to create a pump-free method for increasing the secondary air quantity by focusing on secondary air pipe pulsation. Our study had two aims: one was to create a computation method for predicting the optimum secondary air pipe length that maximizes secondary air, and the other was to verify this method by using actual equipment, and to achieve our target emissions values. Our testing verified that for the secondary air pipe used to amplify the secondary air quantity, the proposed computation method yielded a secondary air pipe length with strong correlation to our measured results.
2014-11-11
Technical Paper
2014-32-0037
Stefano Bernardi, Marco Ferrari, Dario Catanese
Abstract Many two stroke engine for hand-held applications are equipped with muffler that contain a catalyst in order to reduce emissions. However, one of the main problems, is to mantain the performances of the catalyst over time; this often leads to the adoption of systems with increased culling oversized issues related to weight, dimensions and temperature. One of the major causes of degradation of the catalyst is derived from elements of poison present in the oil mixture. This study showed the results obtained by comparing different types of oils of mixture, through durability tests carried out on an engine of a brush cutter.
2014-11-11
Technical Paper
2014-32-0036
Jan Czerwinski, Markus Kurzwart, Andreas Mayer, Pierre Comte
Abstract The progressing exhaust gas legislation for on- and off-road vehicles includes gradually the nanoparticle count limits. The invisible nanoparticles from different emission sources penetrate like a gas into the living organisms and may cause several health hazards. The present paper shows some results of a modern chain saw with & without oxidation catalyst, with Alkylate fuel and with different lube oils. The measurements focused specially on particulate emissions. Particulates were analysed by means of gravimetry (PM) and granulometry SMPS (PN). In this way the reduction potentials with application of the best materials (fuel, lube oil, ox-cat.) were indicated. It has been shown that the particle mass (PM) and the particle numbers (PN), which both consisting almost exclusively of unburned lube-oil, can attain quite high values, but can be influenced by the lube oil quality and can be considerably reduced with an oxidation catalyst.
2014-11-11
Technical Paper
2014-32-0038
Silvana Di Iorio, Francesco Catapano, Paolo Sementa, Bianca Maria Vaglieco, Salvatore Florio, Elena Rebesco, Pietro Scorletti, Daniele Terna
Abstract Great efforts have been paid to improve engine efficiency as well as to reduce the pollutant emissions. The direct injection allows to improve the engine efficiency; on the other hand, the GDI combustion produces larger particle emissions. The properties of fuels play an important role both on engine performance and pollutant emissions. In particular, great attention was paid to the octane number. Oxygenated compounds allow increasing gasoline's octane number and play an important role in PM emission reduction. In this study was analyzed the effect of fuels with different RON and with ethanol and ethers content. The analysis was performed on a small GDI engine. Two operating conditions, representative of the typical EUDC cycle, were investigated. Both the engine performance and the exhaust emissions were evaluated. The gaseous emissions and particle concentration were measured at the exhaust by means of conventional instruments. Particle size distribution function was measured in the range from 5.6 nm to 560 nm by means of an Engine Exhaust Particle Sizer (EEPS).
2014-11-11
Technical Paper
2014-32-0103
Yoshitane Takashima, Hiroki Tanaka, Takahiro Sako, Masahiro Furutani
Abstract Engines using natural gas as their main fuel are attracting attention for their environmental protection and energy-saving potential. There is demand for improvement in the thermal efficiency of engines as an energy-saving measure, and research in this area is being actively pursued on spark ignition engines and HCCI engines. In spark ignition gas engines, improving combustion under lean condition and EGR (exhaust gas recirculation) condition is an issue, and many large gas engines use a pre-chamber. The use of the pre-chamber approach allows stable combustion of lean gas mixtures at high charging pressure, and the reduction of NOx emissions. In small gas engines, engine structure prevents the installation of pre-chambers with adequate volume, and it is therefore unlikely that the full benefits of the pre-chamber approach will be derived. However, recent research on pre-chamber plugs suggests that the pre-chamber combustion approach extends the lean limit even when fuel is not supplied to the pre-chamber, and that this limit is not particularly dependent on the large volume of the pre-chamber.
2014-11-11
Technical Paper
2014-32-0108
Sejun Lee, Kyohei Ozaki, Norimasa Iida, Takahiro Sako
Abstract Recently, a potentiality of Dedicated EGR (D-EGR) concept SI engine has been studied. This concept engine had four cylinders and operated with exhaust gas supplied from the single cylinder to the intake manifold. Compared with conventional SI engines, it was able to increase thermal efficiency and decrease CO, HC, and NOx emission by the high D-EGR ratio 0.25. In this study, numerical analysis of a SI engine with D-EGR system with various D-EGR ratios was conducted for detailed understanding the potentiality of this concept in terms of thermal efficiency and NOx emission. #1 cylinder of assumed engine was used as D-EGR cylinder that equivalence ratio varied from 0.6 to 3.4. Entire exhaust gas from #1 cylinder was recirculated to the other cylinders. The other cylinders run with this exhaust gas and new premixed air and fuel with various equivalence ratios from 0.6-1.0. To study the effect of D-EGR ratio, the number of engine cylinders was considered from 3 to 6, same meaning with D-EGR ratio 0.5-0.2.
2014-11-11
Technical Paper
2014-32-0133
Yuzuru Nada, Yusuke Komatsubara, Thang Pham, Fumiya Yoshii, Yoshiyuki Kidoguchi
Abstract In this study, we evaluated NOx production rates of diesel combustions occurred in a constant volume chamber of a rapid compression machine in order to investigate relationship between flame behaviors and NOx emissions. A total gas sampling device was used to measure the NOx concentration in total gases existing in the chamber at a designated time. An EINOx (Emission Index of NOx) production rate was evaluated on the time history of NOx concentration. Temporal temperature distributions in the chamber were measured with a high speed 2-color thermometry. Gas oil (JIS #2) was used as the fuel. The EINOx production rate increases with increasing injection pressure through temperature rises in flames due to enhanced mixing of fuel vapor with ambient air. An increase in the ambient pressure causes overlaps between flames formed around the nozzle, which reduces the flame temperature. Nevertheless, high reactant concentrations resulting from the elevated ambient pressure slightly increase the net EINOx production rate.
2014-11-11
Technical Paper
2014-32-0079
Yuta Kugimachi, Yusuke Nakamura, Norimasa Iida
Abstract To approach realization of Homogeneous Charge Compression Ignition (HCCI) combustion without external combustion ignition trigger, it is necessary to construct HCCI engine control system. In this study, HCCI research engine equipped with the EGR passage for external EGR and the two-stage exhaust cam for exhaust rebreathed. This system can control the mixing ratio of four gases (air, fuel, rebreathed EGR gas, external EGR gas) of in-cylinder by operating four throttles and fuel injection duration while maintaining acceptable pressure rise rate (PRR) and cycle-to-cycle variation of Indicated Mean Effective Pressure (IMEP), closed-loop control system designed by applying feedback variables (equivalence ratio, combustion-phasing, IMEP) for feedback control. Those control inputs (four throttles and fuel injection) has correlation mutually, control inputs cause interference, response become low and hunching occurs. Therefore, model-based control system with modern control theory which is multi-inputs-multi-outputs system has been constructed to control HCCI combustion.
2014-11-11
Technical Paper
2014-32-0003
Gen Shibata, Ryota Kawaguchi, Soumei Yoshida, Hideyuki Ogawa
Abstract The chemical composition of marketed gasoline varies depending on the crude oil, refinery processes of oil refineries, and season. The combustion characteristics of HCCI engines are very sensitive to the fuel composition, and a fuel standard for HCCI is needed for HCCI vehicles to be commercially viable. In this paper, the effects of the structure of the fuel components on auto-ignition characteristics and HCCI engine performance were investigated. The engine employed in the experiments is a research, single cylinder HCCI engine with a compression ratio of 14.7. The intake manifold was equipped with a heater attachment allowing control of the intake air temperature up to 150 °C at 2000 rpm. Thirteen kinds of hydrocarbons, 4 kinds of paraffins, 3kinds of naphthenes, and 6 kinds of aromatics, were chosen for the investigation, and 20vol% of each of the pure hydrocarbons was blended with the 80 vol% of PFR50 fuel. The HCCI engine was operated with the thirteen kinds of fuels under the same equivalence ratio, and the relative ignitability (the HI index: the hydrocarbon ignitability index, defined in this paper) of each hydrocarbon was calculated from the HTHR CA10 and evaluated.
2014-11-11
Technical Paper
2014-32-0087
Jeff R. Wasil, Thomas Wallner
Abstract Biologically derived isobutanol, a four carbon alcohol, has an energy density closer to that of gasoline and has potential to increase biofuel quantities beyond the current ethanol blend wall. When blended at 16 vol% (iB16), it has identical energy and oxygen content of 10 vol% ethanol (E10). Engine dynamometer emissions tests were conducted on two open-loop electronic fuel-injected marine outboard engines of both two-stroke and four-stroke designs using indolene certification fuel (non-oxygenated), iB16 and E10 fuels. Total particulate emissions were quantified using Sohxlet extraction to determine the amount of elemental and organic carbon. Data indicates a reduction in overall total particulate matter relative to indolene certification fuel with similar trends between iB16 and E10. Gaseous and PM emissions suggest that iB16, relative to E10, could be promising for increasing the use of renewable fuels in recreational marine engines and fuel systems.
2014-11-01
Technical Paper
2014-01-9080
James E. Anderson, Timothy J. Wallington, Robert A. Stein, William M. Studzinski
Abstract Modification of gasoline blendstock composition in preparing ethanol-gasoline blends has a significant impact on vehicle exhaust emissions. In “splash” blending the blendstock is fixed, ethanol-gasoline blend compositions are clearly defined, and effects on emissions are relatively straightforward to interpret. In “match” blending the blendstock composition is modified for each ethanol-gasoline blend to match one or more fuel properties. The effects on emissions depend on which fuel properties are matched and what modifications are made, making trends difficult to interpret. The purpose of this paper is to illustrate that exclusive use of a match blending approach has fundamental flaws. For typical gasolines without ethanol, the distillation profile is a smooth, roughly linear relationship of temperature vs. percent fuel distilled. Hence the use of three points on the curve (T10, T50, and T90, defined as the 10%v, 50%v, and 90%v evaporated temperatures) has been sufficient to define their volatility-related behavior in engines.
2014-10-13
Technical Paper
2014-01-2564
Andrew Smallbone, Amit Bhave, Peter Man
Abstract This paper demonstrates how the validation and verification phase of prototype development can be simplified through the application of the Model Development Suite (MoDS) software by integrating advanced statistical and numerical techniques. The authors have developed and present new numerical and software integration methods to support a) automated model parameter estimation (model calibration) with respect to experimental data and, b) automated global sensitivity analysis through using a High Dimensional Model Representation (HDMR). These methods are demonstrated at 1) a component level by performing systematic parameter estimation of various friction models for heavy-duty IC engine applications, 2) at a sub-component level by performing a parameter estimation for an engine performance model, and 3) at a system level for evaluating fuel efficiency losses (and CO2 sources) in a vehicle model over 160 ‘real-world’ and legislated drive cycles.
2014-10-13
Technical Paper
2014-01-2569
Fabrizio Bonatesta, Salvatore La Rocca, Edward Hopkins, Daniel Bell
Abstract Gasoline Direct Injection engines are efficient devices which are rivaling diesel engines with thermal efficiency approaching the 40% threshold at part load. Nevertheless, the GDI engine is an important source of dangerous ultra-fine particulate matter. The long-term sustainability of this technology strongly depends on further improvement of engine design and combustion process. This work presents the initial development of a full-cycle CFD model of a modern wall-guided GDI engine operated in homogeneous and stoichiometric mode. The investigation was carried out at part-load operating conditions, with early injections during the intake stroke. It included three engine speeds at fixed engine-equivalent load. The spray model was calibrated using test-bed and imaging data from the 7-point high-pressure fuel injectors used in the test engine. Experimental data on combustion were also used for calibration purposes, whereas measurements of engine-out soot number density from a Differential Mobility Spectrometer formed the basis and motive of the investigation.
2014-10-13
Technical Paper
2014-01-2674
Gerardo Valentino, Stefano Iannuzzi
The use of biodiesel or oxygenated fuels from renewable sources in diesel engines is of particular interest because of the low environmental impact that can be achieved. The present paper reports results of an experimental investigation performed on a light duty diesel engine fuelled with biodiesel, gasoline and butanol mixed, at different volume fractions, with mineral diesel. The investigation was performed on a turbocharged DI four cylinder diesel engine for automotive applications equipped with a common rail injection system. Engine tests were carried out at 2500 rpm, 0.8 MPa of brake mean effective pressure selecting a single injection strategy and performing a parametric analysis on the effect of combustion phasing and oxygen concentration at intake on engine performance and exhaust emissions. The experiments demonstrated that the fuel properties have a strong impact on soot emissions. Blends composed of diesel-gasoline or diesel-butanol determined the maximum reduction in smoke emissions compared to the diesel fuel.
2014-10-13
Technical Paper
2014-01-2671
Wuqiang Long, Qiang Zhang, Jiangping Tian, Yicong Wang, Xiangyu Meng
Abstract To directly control the premixed combustion phasing, a novel method called Jet Controlled Compression Ignition (JCCI) is investigated. Experiments were conducted on a single cylinder natural aspirated diesel engine at 3000 r/min without EGR. Numerical model was validated by pressure and heat release rate curves at a fixed spark timing. The simulation results showed that the reacting active radical species with high temperature issued from ignition chamber played an important role on the onset of combustion in JCCI system. The combustion of diesel pre-mixtures was initiated rapidly by the combustion products issued from ignition chamber. Consequently, the experiments of spark timing sweep were conducted to verify the above deduction. The results showed a good linear relationship between spark timing and CA10 and CA50, which validated the ability for direct combustion phasing control in diesel premixed combustion. The NOx and Soot emissions gradually changed with decrease of spark advance angle.
2014-10-13
Technical Paper
2014-01-2678
Buyu Wang, Shi-Jin Shuai, Hong-Qiang Yang, Zhi Wang, Jian-Xin Wang, Hongming Xu
Abstract A study of Multiple Premixed Compression Ignition (MPCI) with heavy naphtha is performed on a light-duty single cylinder diesel engine. The engine is operated at a speed of 1600rpm with the net indicated mean effective pressure (IMEP) from 0.5MPa to 0.9MPa. Commercial diesel is also tested with the single injection for reference. The combustion and emissions characteristics of the heavy naphtha are investigated by sweeping the first (−200 ∼ −20 deg ATDC) and the second injection timing (−5 ∼ 15 deg ATDC) with an injection split ratio of 50/50. The results show that compared with diesel combustion, the naphtha MPCI can reduce NOx, soot emissions and particle number simultaneously while maintaining or achieving even higher indicated thermal efficiency. A low pressure rise rate can be achieved due to the two-stage combustion character of the MPCI mode but with the penalty of high HC and CO emissions, especially at 0.5MPa IMEP. Attributed to the “spray- combustion- spray- combustion” process, the emissions can be controlled by adjusting the first and second injection timing, respectively.
2014-10-13
Technical Paper
2014-01-2675
Xiaobei Cheng, Shuai LI, Jin Yang, Shijun Dong, Zufeng Bao
PPCI in diesel engine is a combustion mode between conventional diesel combustion and homogeneous charge compression ignition (HCCI) combustion, which has the potential to simultaneously reduce NOX and soot emissions and improve thermal efficiency. N-butanol as a kind of clean and renewable biofuel can effectively prolong ignition delay and enhance fuel/air mixing because of their low cetane number, high volatility fuel characteristics, which make it a better alternative fuel to achieve PPCI. In this paper, PPCI combustion in a boosted four-cylinder diesel engine fueled with n-butanol-diesel blends is realized by adjusting injection timing and EGR rate based on single injection. The results show that both early and late injection have long premixed duration, which is helpful to form more homogeneous mixture, and no diffusion combustion is found in heat release rate curve. Premixed combustion and low temperature combustion are the key factors to reduce PM and NOX. With the increase of blending ratio, soot emission can maximumly be reduced by 70%, while NOX shows a slight increase at low load rate.
2014-10-13
Technical Paper
2014-01-2681
Zufeng Bao, Xiaobei Cheng, Liang Qiu, Xingcun Luan
The performance of Partially Premixed Combustion (PPC) relies heavily on the proper mixing between the injected fuel and the in-cylinder gas mixture. This pre-mixing aims to eliminate over-rich regions where the mixture forms soot, and at the same time to avoid the NOX formation region by lowering the combustion temperature by introduction of a large amount of EGR The main effort of this paper focuses on investigating the characteristic of PPC combustion and a suitable injection strategy for achieving the PPC combustion mode. Two injection strategies (i.e. double and single injection) were investigated on a four-cylinder heavy-duty diesel engine operating at low, medium and high load conditions. Injection timing, injection pressure, the pilot-main interval, the pilot injected fuel mass, the ratio between the two pilot injection pulses for the double pilot injection as well as the comparison of single injection mode and multi-injection mode in acquiring PPC was swept to study the combustion behavior in terms of combustion heat release, combustion phase, emissions and different efficiencies.
2014-10-13
Technical Paper
2014-01-2668
Maobin Liu, Bang-Quan He, Hua Zhao
Biobutanol, i.e. n-butanol, as a second generation bio-derived alternative fuel of internal combustion engines, can facilitate the energy diversification in transportation and reduce carbon dioxide (CO2) emissions from engines and vehicles. However, the majority of research was conducted on spark-ignition engines fuelled with n-butanol and its blend with gasoline. A few investigations were focused on the combustion and exhaust emission characteristics of homogeneous charge compression ignition (HCCI) engines fuelled with n-butanol-gasoline blends. In this study, experiments were conducted in a single cylinder four stroke port fuel injection HCCI engine with fully variable valve lift and timing mechanisms on both the intake and exhaust valves. HCCI combustion was achieved by employing the negative valve overlap (NVO) strategy while being fueled with gasoline (Bu0), n-butanol (Bu100) and their blends containing 30% n-butanol by volume (Bu30). The results indicate that, with the increase of n-butanol volume fraction in the blend, the autoignition timing advances and the combustion duration shortens, but indicated mean effective pressure (IMEP) decreases at the same conditions.
2014-10-13
Technical Paper
2014-01-2709
Xianjing Li, Liguang Li
Abstract Gasoline Direct Injection (GDI) engines have attracted interest as automotive power-plants because of their potential advantages in down-sizing, fuel efficiency and in emissions reduction. However, GDI engines suffer from elevated unburned hydrocarbon (HC) emissions during start up process, which are sometimes worsened by misfires and partial burns. Moreover, as the engine is cranked to idle speed quickly in HEVs (Hybrid Electric Vehicle), the transients of quick starts are more dramatically than that in traditional vehicle, which challenge the optimization of combustion and emissions. In this study, test bench had been set up to investigate the GDI engine performances for ISG (Integrated Starter and Generator) HEVs during start up process. Based on the test system, cycle-controlled of the fuel injection mass, fuel injection timing and ignition timing can be obtained, as well as the cycle-resolved measurement of the HC concentrations and NO emissions. This paper focus on the detailed effects of coolant temperature, fuel temperature, cranking speed, injection timing and total equivalence ratio on the combustion and emission characteristics of the GDI engine under stratified combustion condition during the engine quick start process cycle by cycle.
2014-10-13
Technical Paper
2014-01-2712
Dai Liu, Hongming Xu, Ramadhas Arumugam Sakunthalai, Jianyi Tian
Abstract Cold start is a critical operating condition for diesel engines because of the pollutant emissions produced by the unstable combustion and non-performance of after-treatment at lower temperatures. In this research investigation, a light-duty turbocharged diesel engine equipped with a common rail injection system was tested on a transient engine testing bed to study the starting process in terms of engine performance and emissions. The engine (including engine coolant, engine oil and fuel) was soaked in a cold cell at −7°C for at least 8 hours before starting the test. The engine operating parameters such as engine speed, air/fuel ratio, and EGR rate were recorded during the tests. Pollutant emissions (Hydrocarbon (HC), NOx, and particles both in mode of nucleation and accumulation) were measured before and after the Diesel Oxidation Catalyst (DOC). The results show that conversion efficiency of NOx was higher during acceleration period at −7°C start than the case of 20°C start.
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