Browse Topic: PCCI engines

Items (466)

Control oriented engine model development for Model-based PPC control

2022-01-057503/29/2022

In this work, a model-based control approach for Partially Premixed Combustion (PPC) engines is introduced. PPC is a next-generation combustion technology, which has the potential to achieve both ultra-low emissions and high efficiency. As the PPC concept is characterized by a complex chemical-physical process of low-temperature kinetic reactions, it lacks direct trigger of ignition and combustion as well as it is sensitive to varying operating conditions. These complex nature of PPC makes it challenging to control the combustion for optimum efficiency and emissions at broad engine operation with low cyclic variability and without exceeding the maximum allowed in-cylinder pressure rise rate or peak pressure. The nonlinear relationship between the control input and combustion system response makes that conventional lookup table-based control might need too many maps and calibration effort, thus no longer feasible for real operation scenarios. A model-based control approach is proposed

Pan, Wang, Bekdemir, Cemil, Willems, Frank

Numerical Investigations on Split Injection Strategies to Reduce Unburned Hydrocarbon Emissions of a Premixed Charge Compression Ignited Light-Duty Small-Bore Diesel Engine

2022-01-055303/29/2022

Premixed Charge Compression Ignition (PCCI) is a promising low-temperature combustion (LTC) strategy to achieve a simultaneous reduction in oxides of nitrogen (NOx) and soot emissions without relying on after-treatment devices. One of the significant shortcomings of PCCI operation is a high unburned hydrocarbon (HC) and carbon monoxide (CO) emissions resulting from fuel spray-wall impingement due to early injection of diesel. Narrow-angle direct injection (NADI) helps in reducing the wall wetting of fuel. But it is effective only at lower loads. At mid and higher loads, it increases soot and CO emissions in small-bore diesel engines due to the formation of fuel-rich pockets in the piston bowl region. The present study intends to address this problem using a split injection strategy. A 3-D CFD model is developed and validated with experimental data at two load conditions. Simulations are performed using a commercial CONVERGE CFD software. Split injection strategies are explored using

Pradeep, V, Krishnasamy, Anand

METHODOLOGICAL APPROACHES TO CONTROL HC AND CO EMISSIONS DURING COLD CONDITIONS

2022-01-054403/29/2022

Diesel Engines are known for its low fuel consumption and at the same time for higher emission formation (NOx, HC, CO and SOOT). Meeting Emission and CO2 targets simultaneously become tough challenge for the Combustion Engineer. HCCI and PCCI combustion concepts allow the reduction of NOx and Soot simultaneously to very low levels with help of Exhaust gas re-circulation (EGR) while maintaining the CO2 emissions advantage of a diesel Engine But due to the low Combustion temperatures, HC and CO will rise drastically, especially when the catalyst bed temperature is not enough to reach light-off temperature to initiate the after-treatment process. This condition will become serve in Lower Engine temperatures (Cold condition) due to the heterogeneous nature of Diesel Combustion and also affects the BSFC of an Engine. At first multiple injection strategies (Pilot quantity and Pilot separation) has been studied to control both HC and CO by increasing the global combustion temperature. In

Mutta, Surendranath

Effect of Injection Parameters on the Premixed Charge Compression Ignition Combustion in a Small-Bore Light Duty Diesel Engine – A CFD Study

2021-01-117409/21/2021

Premixed charged compression ignition (PCCI) is a promising low temperature combustion strategy for achieving simultaneous reduction of oxides of nitrogen (NOx) and soot emissions in diesel engines. However, early direct injection results in significant penalty in fuel economy, high unburned hydrocarbon (HC) and carbon monoxide (CO) emissions, especially in small-bore diesel engines. In the present work computational fluid dynamic investigations are carried out in a small-bore diesel engine using a commercial CFD software, CONVERGE. The computational models are validated with experimental results at two different load conditions, 20% and 40% of rated load. The validated models are used to carry out parametric investigations on the effects of fuel injection parameters, namely start of fuel injection timing, injection pressure and spray cone angle on PCCI combustion. The fuel-air equivalence ratio, temperature and emission contours are used to get more insight into the effect of fuel

Pradeep, V, Krishnasamy, Anand

7.0.101 - A New Image De-hazing Method for Safety Critical ADAS Applications

SAE-PP-0027702/04/2021

Driver safety and Advanced Driver Assistance Systems (ADAS) is gaining lot of importance these days. In some countries, there are strict regulations in place which mandate the use of certain ADAS features in automobiles. However, as the need for these safety critical systems increases, the challenges associated also increase. These challenges can arise due to technology, human factors or due to nature. In countries like India, where one can expect different weather conditions with changing geography, the associated challenges are mainly due to the natural factors like haze, fog, rain and smoke. This poses a challenging problem in terms of visibility for the drivers as well as in vision based ADAS; thereby, leading to many fatal road accidents. In this paper, a novel pre-processing technique, which addresses the interesting problem of enhancing the perceptual visibility of an image that is degraded by atmospheric haze, is proposed. The solution to this problem is presented by combining

Lname, Fname

6.0.116 - Development of 6 Years Old Child Virtual Model by Automatic Scaling

SAE-PP-0027102/04/2021

Traffic accidents cause one of the highest numbers of severe injuries in the whole population. The numbers of deaths or seriously injured citizens prove that traffic accidents and their consequences are still a serious problem to be solved. A lot of effort is devoted to both passive and active safety systems development. The transportation standards usually define safety requirements by regulations (e.g. ECE-R94, 96/79/EC and ECE-R95, 96/27/EC in Europe) with specific dummies for children to be used. The dummies include hardware sensors for monitoring accelerations, loads and other signals and each dummy is developed for a specific scenario, but there are limitations of these dummies, such as only a specific age or calibration just for a specific test. Taking into account that the consequence of a traffic accident is highly influenced by the stature of the body, virtual human body models, including those for children, start to play a significant role because they can be scaled or even

Mutagaana, Festo

6.0.101 - Piston Sealing System Structure Design for Automobile's Lightweight Auto-Transmission

SAE-PP-0025702/04/2021

Current automobile's auto-transmission has problems of defects and cost reduction because of welding process and very complicated assembly process due to individualized transmission piston and sealing components. Also, size and heavy weight of transmission piston components are the source of low mileage because they are made of aluminum, steel material. In this study, therefore, we perform structure design for piston sealing system which integrates piston and sealing material for automobile's lightweight auto-transmission. Also performed stress analysis through finite element analysis to secure required suitable strength when internal pressure is applied after assemble.

Mutagaana, Festo

2.0.101 - Experimental Study of cooling of Continuously Variable Transmission (CVT) in Scooter

SAE-PP-0021002/01/2021

The continuously variable transmission (CVT), which was conceptualized more than 500 years ago, is just now beginning to replace traditional transmissions in some automobiles. It is mostly used in scooter transmission. Engine power is transmitted to wheel through belt drive between two pulleys. The diameter of belt contact with pulley can change continuously and hence provide infinite gear ratios between driver and driven shafts. This technology leads to a smoother ride of vehicle. Heat is generated inside CVT due to friction between drive belt and clutch pulley. Amount of heat generated is even more due to clutch slippage during acceleration and deceleration. This will affect the service life of CVT components such as front movable drive (FMD), clutch pulley, clutch outer, and belt. In scooters generally, air cooling is preferred over liquid cooling. Cooling is achieved by incorporating centrifugal fan inside CVT housing. For better durability/service life, the degree of heat

Mutagaana, Festo

Infrared/Visible Optical Diagnostics of RCCI Combustion with Dieseline in a Compression Ignition Engine

2020-01-055704/14/2020

Compression ignition engines are widely used for transport and energy generation due to their high efficiency and low fuel consumption. To minimize the environmental impact of this technology, the pollutant emissions levels at the exhaust are strictly regulated. To reduce the after-treatment needs, alternative strategies as the low temperature combustion (LTC) concepts are being investigated recently. The reactivity controlled compression ignition (RCCI) uses two fuels (direct- and port- injected) with different reactivity to control the in-cylinder mixture reactivity by adjusting the proportion of both fuels. In spite of the proportion of the port-injected fuel is typically higher than the direct-injected one, the characteristics of the latter play a main role on the combustion process. Use of gasoline for direct injection is attractive to retard the start of combustion and to improve the air-fuel mixing process. In this work, the influence of the direct-injected fuel properties on

Sequino, Luigi, Mancaruso, Ezio, Monsalve-Serrano, Javier, Garcia, Antonio

Use of Butanol Blend Fuels on Diesel Engines - Effects on Combustion and Emissions

2020-01-0333-TEST-REC04/14/2020

Butanol, a four-carbon alcohol, is considered in the last years as an interesting alternative fuel, both for Diesel and for gasoline application. Its advantages for engine operation are: good miscibility with gasoline and diesel fuels, higher calorific value than ethanol, lower hygroscopicity, lower corrosivity and possibility of replacing aviation fuels. Like ethanol, butanol can be produced as a biomass-based renewable fuel or from fossil sources. In the research project, DiBut (Diesel and butanol) addition of butanol to Diesel fuel was investigated from the points of view of engine combustion and of influences on exhaust aftertreatment systems and emissions. One investigated engine (E1) was with emission class “EU Stage 3A” for construction machines, another one, engine (E2) was HD Euro VI. The most important findings are: with higher butanol content, there is a lower heat value of the fuel and there is lower torque at full load. With Bu30 the conversion rates of CO and HC in the

Engelmann, Danilo, Czerwinski, Jan, Nauroy lng, Hervé, Comte, Pierre, Hüssy lng, Andreas

Numerical Investigation of the Combustion Kinetics of Partially Premixed Combustion (PPC) Fueled with Primary Reference Fuel

2020-01-0554-TEST-REC04/14/2020

This work numerically investigates the detailed combustion kinetics of partially premixed combustion (PPC) in a diesel engine under three different premixed ratio fuel conditions. A reduced Primary Reference Fuel (PRF) chemical kinetics mechanism was coupled with CONVERGE-SAGE CFD model to predict PPC combustion under various operating conditions. The experimental results showed that the increase of premixed ratio (PR) fuel resulted in advanced combustion phasing. To provide insight into the effects of PR on ignition delay time and key reaction pathways, a post-process tool was used. The ignition delay time is related to the formation of hydroxyl (OH). Thus, the validated Converge CFD code with the PRF chemistry and the post-process tool was applied to investigate how PR change the formation of OH during the low-to high-temperature reaction transition. The reaction pathway analyses of the formations of OH before ignition time were investigated. It was found that in the case of PR0

Zhao, Yuanyuan, Wang, Hu, Liu, Xinlei, Liu, Daojian, Chenchen, Wang, Zhu, Hongyan, Zheng, Zunqing, Yao, Mingfa

Development of Fast Idle Catalyst Light-Off Strategy for Gasoline Compression Ignition Engine - Part 1

2020-01-031604/14/2020

The present investigation pertains to the development of fast idle catalyst light-off strategy for a light duty gasoline compression ignition (GCI) engine. The engine cold start fast idle operation poses a problem of increased criteria emissions if the catalyst is not activated during the warm up period. Therefore, a control strategy is proposed here to minimize the criteria pollutants during the fast idle phase via enabling fast catalyst light off in a GCI engine and relying on the spark ignition of a globally stoichiometric fuel air mixture. The engine has unique design features such as certain geometry configuration between spark plug and fuel injector arrangement, and the location of spark plug in a high compression ratio (CR) diesel-like combustion chamber. The experiments were performed in a single cylinder GCI engine at cold start fast idle conditions using certification gasoline fuel (RON 91). Split fuel injection and extremely retarded spark timing strategy are applied to

Raman, Vallinayagam, Viollet, Yoann, Chang, Junseok

Varying Intake Stroke Injection Timing of Wet Ethanol in LTC

2020-01-023704/14/2020

Computational Fluid Dynamics (CFD) modeling was used to investigate the effects of the direct injection of wet ethanol at various injection timings during the intake stroke in a diesel engine with a shallow bowl piston. Thermally Stratified Compression Ignition (TSCI) has been proposed to expand the operating range of Low Temperature Combustion (LTC) by broadening the temperature distribution in the cylinder prior to ignition. TSCI is accomplished by injecting either water or a water-fuel mixture with a high latent heat of vaporization like wet ethanol. This current study focuses on isolating the effects that injecting such a high heat of vaporization mixture during the intake stroke has on the distribution of temperature and equivalence ratio in the cylinder before the onset of combustion. A CONVERGE 3-D CFD model of a single cylinder diesel research engine using Reynolds Averaged Naiver Stokes (RANS) turbulence modeling was developed and validated against experimental data. Then

O'Donnell, Patrick C., Rahimi Boldaji, Mozhgan, Gainey, Brian, Lawler, Benjamin

Use of Butanol Blend Fuels on Diesel Engines - Effects on Combustion and Emissions

2020-01-0333

04/14/2020

Engelmann, Danilo, Czerwinski, Jan, Nauroy lng, Hervé, Comte, Pierre, Hüssy lng, Andreas

Transition from HCCI to PPC: Investigation of the Effect of Different Injection Timing on Ignition and Combustion Characteristics in an Optical PPC Engine

2020-01-055904/14/2020

The partially premixed combustion (PPC) concept is regarded as an intermediate process between the thoroughly mixed Homogeneous charge compression ignition (HCCI) combustion and compression ignition (CI) combustion. It’s a combination of auto-ignition mode, a fuel-rich premixed combustion mode, and a diffusion combustion mode. The concept has both high efficiency and low soot emission due to low heat losses and less stratified fuel and air mixtures compared to conventional diesel CI. The mechanisms behind the combustion process are not yet very well known. This work focuses on the efficiency and the in-cylinder process in terms of fuel distribution and the initial phase of the combustion. More specifically, double injection strategies are compared with single injection strategies to achieve different levels of stratification, ranging from HCCI to PPC like combustion as well as poor (43%) to good (49%) of gross indicated efficiency. The experiments were performed in an optical heavy

Zhang, Miao, Derafshzan, Saeed, Xu, Leilei, Bai, Xue-Song, Richter, Mattias, Lundgren, Marcus

Nonlinear Identification Modeling for PCCI Engine Emissions Prediction Using Unsupervised Learning and Neural Networks

2020-01-055804/14/2020

Premixed charged compression ignition (PCCI) is an advanced combustion strategy, which has the potential to achieve ultra-low nitrogen oxide and soot emissions at high thermal efficiencies. PCCI combustion is characterized by a complex nonlinear chemical-physical process, which indicates that a physical description involves significant development times and also high computation cost. This paper presents a method to use cylinder pressure data and engine operations parameters for prediction of PCCI engine emissions by unsupervised learning and nonlinear identification techniques. The proposed method first uses principal component analysis (PCA) to reduce the dimension of the cylinder-pressure data. Based on the PCA analysis, a multi-input multi-out model was developed for nitrogen oxide and soot emission prediction by multi-layer perceptron (MLP) neural network. Before the training process, a second principal component analysis was done to reduce the input dimension with hyper

Pan, Wang, Korkmaz, Metin, Beeckmann, Joachim, Pitsch, Heinz

Control of Ignition Timing and Combustion Phase by Means of Injection Strategy for Jet-Controlled Compression Ignition Mode in a Light Duty Diesel Engine

2020-01-055504/14/2020

Controllability of ignition timing and combustion phase by means of dual-fuel direct injection strategy in jet-controlled compression ignition mode were investigated in a light-duty prototype diesel engine. Blended fuel with lower reactivity was delivered in the early period of compression stroke to form the premixed charge, while diesel fuel which has higher reactivity was injected near TDC to trigger the ignition. The effects of several important injection parameters including pre-injection timing, jet-injection timing, pre- injection pressure and ratio of pre-injection in the total heat value of injected fuel were discussed. Numerical Simulation by using CFD software was also conducted under similar operating conditions. The experimental results indicate that the jet-injection timing shows robust controllability on the start of combustion under all the engine load conditions. Pre-injection timing/pressure/ratio show little impact on the start of combustion due to low reaction

Zhu, Jingyu, Bo, Li, Long, Wuqiang

Impact of Multiple Injection Strategies on Efficiency and Combustion Characteristics in an Optical PPC Engine

2020-01-113104/14/2020

Partially premixed combustion (PPC) is a promising way to achieve high thermal efficiency and low emissions, especially by using multiple injection strategies. The mechanisms behind PPC efficiency are still to be explained and explored. In this paper, multiple injections have been used to affect the gross indicated efficiency in an optical PPC engine modified from a Volvo MD13 heavy-duty diesel engine. The aim is both to improve and impair the gross indicated efficiency to understand the differences. The combustion natural luminosity is captured by a high-speed camera, and the distribution of fuel, oxygen, and temperature during the combustion process has been further explored by CFD simulation. The results show that with the right combination of the pilot, main, and post injection the gross indicated efficiency can be improved. Using a post injection in a triple-injection case show to have less effect on the combustion phasing than pilot injection in a double-injection case, while it

Zhang, Miao, Xu, Leilei, Derafshzan, Saeed, Bai, Xue-Song, Richter, Mattias, Lundgren, Marcus

Numerical Investigations on Strong Knocking Combustion under Advanced Compression Ignition Conditions

2020-01-113704/14/2020

Homogeneous charge compression ignition (HCCI) combined with high compression ratio is an effective way to improve engines’ thermal efficiency. However, the severe thermodynamic conditions at high load may induce knocking combustion thus damage the engine body. In this study, advanced compression ignition knocking characteristics were parametrically investigated through RCM experiments and simulation analysis. First, the knocking characteristics were optically investigated. The experimental results show that there even exists detonation when the knock occurs thus the combustion chamber is damaged. Considering both safety and costs, the effects of different initial conditions were numerically investigated and the results show that knocking characteristics is more related to initial pressure other than initial temperature. The initial pressure has a great influence on peak pressure and knock intensity while the initial temperature on knock onset. Further analysis shows that knock

Chen, Lin, Pan, Jiaying, Zhao, Jianfu

Numerical Investigation of the Combustion Kinetics of Partially Premixed Combustion (PPC) Fueled with Primary Reference Fuel

2020-01-0554

04/14/2020

Zhao, Yuanyuan, Wang, Hu, Liu, Xinlei, Liu, Daojian, Chenchen, Wang, Zhu, Hongyan, Zheng, Zunqing, Yao, Mingfa

Model Based Control for Premixed Charge Compression Ignition Diesel Engine

2020-01-115004/14/2020

Premixed charge compression ignition (PCCI) combustion is effective to reduce diesel engine harmful exhaust gas and improve fuel consumption. However, PCCI combustion has a problem of low combustion stability compared to diesel diffusive combustion, and there are few examples of application to mass production engines. In addition to engine speed and load, it needs complicated injection control according to environmental conditions such as outside air temperature, pressure, and engine water temperature, and transient changes such as supercharging delay, EGR delay, and intake air temperature delay. Although there is example where the control maps are switched according to the intake condition, it needs huge maps considering all the parameters mentioned above. Thus it requires a significant calibration man-hour. And this may lead to deterioration of reliability such as combustion noise and torque fluctuation. In this study, the physical model is applied to calculate the ignitability in

Nishida, Kentaro, Shimizu, Hajime

Numerical Analysis of Fuel Impacts on Advanced Compression Ignition Strategies for Multi-Mode Internal Combustion Engines

2020-01-112404/14/2020

Multi-mode combustion strategies may provide a promising pathway to improve thermal efficiency in light-duty spark ignition (SI) engines by enabling switchable combustion modes, wherein an engine may operate under advanced compression ignition (ACI) at low load and spark-assisted ignition at high load. The extension from the SI mode to the ACI mode requires accurate control of intake charge conditions, e.g., pressure, temperature and equivalence ratio, in order to achieve stable combustion phasing and rapid mode-switches. This study presents results from computational fluid dynamics (CFD) analysis to gain insights into mixture charge formation and combustion dynamics pertaining to auto-ignition processes. The computational study begins with a discussion of thermal wall boundary condition that significantly impacts the combustion phasing. The validated model setup with the properly optimized boundary condition was verified across broad range of engine load conditions with varying air

Kim, Sayop, Kim, Joohan, Shah, Ashish, Scarcelli, Riccardo, Rockstroh, Toby

Combustion System Optimization of a Light-Duty GCI Engine Using CFD and Machine Learning

2020-01-131304/14/2020

In this study, the combustion system of a light-duty compression ignition engine running on a market gasoline fuel with Research Octane Number (RON) of 91 was optimized using computational fluid dynamics (CFD) and Machine Learning (ML). This work was focused on optimizing the piston bowl geometry at two compression ratios (CR) (17 and 18:1) and this exercise was carried out at full-load conditions (20 bar indicated mean effective pressure, IMEP). First, a limited manual piston design optimization was performed for CR 17:1, where a couple of pistons were designed and tested. Thereafter, a CFD design of experiments (DoE) optimization was performed where CAESES, a commercial software tool, was used to automatically perturb key bowl design parameters and CONVERGE software was utilized to perform the CFD simulations. At each compression ratio, 128 piston bowl designs were evaluated. Subsequently, a Machine Learning-Grid Gradient Algorithm (ML-GGA) approach was developed to further optimize

Badra, Jihad, khaled, Fethi, Sim, Jaeheon, Pei, Yuanjiang, Viollet, Yoann, Pal, Pinaki, Futterer, Carsten, Brenner, Mattia, Som, Sibendu, Farooq, Aamir, Chang, Junseok

Thermal Efficiency Improvements with Split Primary Fuel Injections in Semi-Premixed Diesel Combustion with Multi-Peak Shaped Heat Release

2019-01-217012/19/2019

To improve the combustion characteristics in semi-premixed diesel combustion, consisting in the first-stage premixed combustion of the primary fuel injection and the second-stage spray combustion of the secondary injection, the effect of splitting the primary injection was investigated in a diesel engine and analyzed with a CFD. The indicated thermal efficiency improves due to reductions in heat transfer losses to the in-cylinder wall and the combustion noise is suppressed with the split primary injections. The CFD analysis showed that the reduction in heat transfer loss with the split primary injections is due to a decrease in the combustion quantity near the combustion chamber wall.

Inaba, Kazuki, Masuko, Yosuke, Zhang, Yanhe, Kobashi, Yoshimitsu, shibata, Gen, Ogawa, Hideyuki

A Study of a Lean Homogeneous Combustion Engine System with a Fuel Reformer Cylinder

2019-01-217712/19/2019

The Dual-Fuel (DF) combustion is a promising technology for efficient, low NOx and low exhaust particulate matter (PM) engine operation. To achieve equivalent performance to a DF engine with only the use of conventional liquid fuel, this study proposes the implementation of an on-board fuel reformation process by piston compression. For concept verification, DF combustion tests with representative reformed gas components were conducted. Based on the results, the controllability of the reformed gas composition by variations in the operating conditions of the reformer cylinder were discussed.

Asai, Go, Tokuoka, Yuki, Bayer, Thomas, Ishiguro, Shuntaro, Shibata, Gen, Ogawa, Hideyuki, Kobashi, Yoshimitsu, Watanabe, Yusuke

Fuel Flexibility Study of a Compression Ignition Engine at High Loads

2019-01-219312/19/2019

Engine experiments were performed on a single-cylinder heavy-duty engine at relatively high loads to investigate the regions where the combustion characteristics are unchanged regardless of the fuel octane number. Primary Reference Fuels (PRFs) and three different commercial fuels with RON values ranging from 0 to 100 were tested in this study. A sweep of net indicated mean effective pressure (IMEPNet) of 5 to 20 bar, absolute intake pressure of 1.5 to 2.8 bar, exhaust gas recirculation (EGR) of 0 to 40%, and fuel injection pressure of 700 to 1400 bar were performed to investigate the combustion characteristics, ignition delay time, combustion duration, efficiency, and emissions. At the highest load point (IMEPNet = 20 bar), all the fuels burn as in conventional diesel combustion. Despite the wide range of octane numbers, all fuels had similar ignition delay time, combustion duration, indicated efficiency, and emissions at 10 to 20 bar IMEPNet. It follows that CI mode is the only

AlRamadan, Abdullah S., Houidi, Moez Ben, Nyrenstedt, Gustav, Johansson, Bengt

Numerical Optimization of Compression Ratio for a PPC Engine running on Methanol

2019-01-216812/19/2019

Partially premixed combustion (PPC) has shown to produce high gross indicated efficiencies while yielding lower pollutant emissions, such as oxides of nitrogen and soot, than conventional diesel combustion. Gasoline fuels with a research octane number (RON) of 60-70 have been proposed as optimal for PPC as they balance the trade-off between ensuring good combustion stability at low engine loads and avoiding excessive peak pressure rise rates at high loads. However, measures have to be taken when optimizing the engine operating parameters to avoid soot emissions. In contrast, methanol has a much lower propensity for soot formation. However, due to a higher RON of methanol the required intake temperature is higher for the same engine compression ratio to ensure auto-ignition at an appropriate timing. Increasing the compression ratio allows a lower intake temperature and improves combustion stability as well as engine brake efficiency. Nevertheless, a higher compression ratio generally

Svensson, Erik, Verhelst, Sebastian

Characteristics Investigation on Di Diesel Engine with Nano-Particles as an Additive in Lemon Grass Oil

2019-28-008110/11/2019

In this experimental study, combustion, performance & emission characteristics of a single cylinder D.I. diesel engine is analyzed using lemon grass oil and diesel blend B20. The alumina (Al2O3) nano-particles of 10, 20 and 30 parts per million (B20A10, B20A20, B20A30) are assorted with prepared fuel blend through an ultrasonicator which would help to fetch an unvarying suspension of nano-particles over the blend fuel. SEM analysis and X-ray diffraction have been done for the alumina nano-particles to test the size of the particles that are blended to the bio-fuel blends. The chemical reactivity and rate of mixing are better though the characteristics of nano-particles exhibit high exterior area/capacity ratio during combustion that ultimately results in good characteristics of a diesel engine. Among test fuels, B20A20 shows healthier performance both in relationships of efficiency & emissions such as Nitrous oxide (NOx), hydrocarbon (HC), Carbon monoxide (CO), and Smoke. The ŋBTE for

Balasubramanian, Dhinesh, Papla Venugopal, Inbanaathan, Viswanathan, Karthickeyan

Experimental and Numerical Investigation of the Maximum Pressure Rise Rate for an LTC Concept in a Single Cylinder CI Engine

2019-24-002309/09/2019

In the foreseeable future, the transportation sector will continue to rely on internal combustion engines. Therefore, reduction of engine-out emissions and increase in engine efficiency are important goals to meet future legislative regulations and restricted fuel resources. One viable option, which provides lower peak temperatures and increased mixture homogeneity and thus simultaneously reduces nitric oxide as well as soot, is a low-temperature combustion (LTC) concept. However, this might result in an increase of unburnt hydrocarbon, carbon monoxide, and combustion noise due to early combustion phasing and lower engine efficiency. Various studies show that these drawbacks can be compensated by advanced injection strategies, e.g. by employing multiple injections. The aim of this work is to identify the optimum injection strategy, which enables a wide range of engine operating points in LTC mode with reduced engine-out emissions. To achieve this goal, experiments with variations in

Korkmaz, Metin, Lakshmanan, Raghavan, Falkenstein, Tobias, Beeckmann, Joachim, Pitsch, Heinz

Study of Fuel Octane Sensitivity Effects on Gasoline Partially Premixed Combustion Using Optical Diagnostics

2019-24-002509/09/2019

Partially premixed combustion (PPC) is a low-temperature combustion concept that could deliver higher engine efficiency, as well as lower emissions. Gasoline-like fuel compression ignition (GCI) is beneficial for air/fuel mixing process under PPC mode because of the superior auto-ignition resistance to prolong ignition delay time. In current experiments, three surrogate fuels with same research octane number (RON77) but different octane sensitivities (OS), PRF77 (S = 0), TPRF77-a (S = 3) and TPRF77-b (S = 5), are tested in a full-transparent single cylinder AVL optical compression ignition (CI) engine at low load conditions. Aiming at investigating the fuel octane sensitivity effect on engine combustion behavior as well as emissions under GCI-PPC mode, engine parameters, and emission data during combustion are compared for the test fuels with a change of injection timing. In addition, in order to get a deeper insight into fuel OS effect on GCI-PPC mode, high-speed natural flame

Shi, Hao, An, Yanzhao, Johansson, Bengt

HCCI with Wet Ethanol: Investigating the Charge Cooling Effect of a High Latent Heat of Vaporization Fuel in LTC

2019-24-002409/09/2019

The combustion phasing of Homogeneous Charge Compression Ignition combustion is incredibly sensitive to intake temperature. Controlling the intake temperature on a cycle-to-cycle basis is one-way to control combustion phasing, however accomplishing this with an intake air heater/intercooler is unfeasible. One possible way to control the intake temperature is through the direct injection of fuel. The direct injection of fuel during the intake stroke cools the charge via evaporative cooling. Some heat is absorbed from the incoming air, lowering the in-cylinder temperature, while some heat is absorbed from the piston/cylinder walls if the spray reaches the walls. The amount of heat that is absorbed from the air vs. the walls depends on the spray penetration length. The available spray penetration length can be controlled by the injection timing during the intake stroke. Therefore, if a high latent heat of vaporization fuel is used, the intake valve closing temperature will become very

Gainey, Brian, Gohn, James, Yan, Ziming, Malik, Khurram, Rahimi Boldaji, Mozhgan, Lawler, Benjamin

Validation and Analysis of Heat Losses Prediction Using Conjugate Heat Transfer Simulation for an Internal Combustion Engine

2019-24-009109/09/2019

New technologies are required to improve engine thermal efficiency. For this it is necessary to use all the tools available nowadays, in particular computational tools, which allow testing the viability of different solutions at reduced cost. In addition, numerical simulations often provide more detailed information than experimental tests. Such is the case for the study of the heat transfer through the walls of an engine. Conjugate Heat Transfer (CHT) simulations permit precise calculations of the heat transfer from gas to walls throughout the whole engine cycle, and thus it is possible to know such details as the instantaneous heat losses and wall temperature distribution on the walls, which no experiment can give. Nevertheless, it is important to validate CHT calculations, either with some experimental measurements or with some other reliable tool, such as 0D-1D modelling known to work well. The proposed work is based on the CHT simulation of the heat transfer to the walls of an

Broatch, Alberto, Margot, Xandra, Garcia-Tiscar, Jorge, Escalona, Johan

A Computationally Efficient Progress Variable Approach for In-Cylinder Combustion and Emissions Simulations

2019-24-001109/09/2019

The use of complex reaction schemes is accompanied by high computational cost in 3D CFD simulations but is particularly important to predict pollutant emissions in internal combustion engine simulations. One solution to tackle this problem is to solve the chemistry prior the CFD run and store the chemistry information in look-up tables. The approach presented combines pre-tabulated progress variable-based source terms for auto-ignition as well as soot and NOx source terms for emission predictions. The method is coupled to the 3D CFD code CONVERGE v2.4 via user-coding and tested over various speed and load passenger-car Diesel engine conditions. This work includes the comparison between the combustion progress variable (CPV) model and the online chemistry solver in CONVERGE 2.4. Both models are compared by means of combustion and emission parameters. A detailed n-decane/α-methyl-naphthalene mechanism, comprising 189 species, is used for both online and tabulated chemistry simulations

Matrisciano, Andrea, Netzer, Corinna, Werner, Adina, Borg, Anders, Seidel, Lars, Mauss, Fabian

A Coupled Tabulated Kinetics and Flame Propagation Model for the Simulation of Fumigated Medium Speed Dual-Fuel Engines

2019-24-009809/09/2019

The present work describes the numerical modeling of medium-speed marine engines, operating in a fumigated dual-fuel mode, i.e. with the second fuel injected in the ports. This engine technology allows reducing engine-out emissions while maintaining the engine efficiency and can be fairly easily retrofitted from current diesel engines. The main premixed fuel that is added can be a low-carbon one and can additionally be of a renewable nature, thereby reducing or even completely removing the global warming impact. To fully optimize the operational parameters of such a large marine engine, computational fluid dynamics can be very helpful. Accurately describing the combustion process in such an engine is key, as the prediction of the heat release and the pollutant formation is crucial. Auto-ignition of the diesel fuel needs to be captured, followed by the combustion and flame propagation of the premixed fuel. In this work, an approach based on tabulated kinetics has been used, to include

Decan, Gilles, Lucchini, Tommaso, D'Errico, Gianluca, Verhelst, Sebastian

A Study of Flow Characteristics on the Diesel-Gasoline Dual-Fuel Combustion by 3-D CFD

2019-24-011709/09/2019

Various advanced combustion concepts, which can achieve higher thermal efficiency and emissions reduction, have been suggested as the emissions regulation gets stricter. Dual-fuel combustion that operates by using different fuels having both premixed and non-premixed combustion characteristics is one of the viable alternatives. In dual-fuel combustion, it is critical to understand air-fuel mixture distribution as it determines the ignition spot and following combustion phase. The fuel distribution in the engine is affected by various factors, such as chamber geometry, injection strategy or in-cylinder flow motion. Furthermore, among them, in-cylinder motion, usually described in terms of swirl or tumble motion, is mostly affected by in-cylinder port geometry. In this paper, 3-dimensional Computational Fluid Dynamics (CFD) was used to investigate the effect of in-cylinder flow motion in dual-fuel combustion. Two head and port geometries were used in the simulations. One is the

Moon, Sunyoung, Chu, Sanghyun, Nam, Taewoo, Min, Kyoungdoug

Virtual Investigation of Real Fuels by Means of 3D-CFD Engine Simulations

2019-24-009009/09/2019

The reduction of both harmful emissions (CO, HC, NOx, etc.) and gases responsible for greenhouse effects (especially CO2) are mandatory aspects to be considered in the development process of any kind of propulsion concept. Focusing on ICEs, the main development topics are today not only the reduction of harmful emissions, increase of thermodynamic efficiency, etc. but also the decarbonization of fuels which offers the highest potential for the reduction of CO2 emissions. Accordingly, the development of future ICEs will be closely linked to the development of CO2 neutral fuels (e.g. biofuels and e-fuels) as they will be part of a common development process. This implies an increase in development complexity, which needs the support of engine simulations. In this work, the virtual modeling of real fuel behavior is addressed to improve current simulation capabilities in studying how a specific composition can affect the engine performance. The goal is to create a series of models that

Cupo, Francesco, Chiodi, Marco, Bargende, Michael, Koch, Daniel, Wachtmeister, Georg, Wichelhaus, Donatus

Zero-Dimensional Heat Release Modeling Framework for Gasoline Compression-Ignition Engines with Multiple Injection Events

2019-24-008309/09/2019

A zero-dimensional heat release model was developed for compression ignition engines. This type of model can be utilized for parametric studies, off-line optimization to reduce experimental efforts as well as model-based control strategies. In this particular case, the combustion model, in a simpler form, will be used in future efforts to control the combustion in compression ignition engines operating on gasoline-like fuels. To allow for a realistic representation of the in-cylinder combustion process, a spray model has been employed to allow for the quantification of fuel distribution as well as turbulent kinetic energy within the injection spray. The combustion model framework is capable of reflecting premixed as well as mixing controlled combustion. Fuel is assigned to various combustion events based on the air-fuel mixture within the spray. The mixing controlled combustion consists of two separate combustion events; one occurring within the fuel spray, which is characterized by

Pamminger, Michael, Hall, Carrie, Wang, Buyu, Wallner, Thomas, Rajkumar, M

A Guide to Uncertainty Quantification for Experimental Engine Research and Heat Release Analysis

03-12-05-003308/22/2019

Performing an uncertainty analysis for complex measurement tasks, such as those found in engine research, presents unique challenges. Also, because of the excessive computational costs, modeling-based approaches, such as a Monte Carlo approach, may not be practical. This work provides a traditional statistical approach to uncertainty analysis that incorporates the uncertainty tree, which is a graphical tool for complex uncertainty analysis. Approaches to calculate the required sensitivities are discussed, including issues associated with numerical differentiation, numerical integration, and post-processing. Trimming of the uncertainty tree to remove insignificant contributions is discussed. The article concludes with a best practices guide in the Appendix to uncertainty propagation in experimental engine combustion post-processing, which includes suggested post-processing techniques and down-selected functional relationships for uncertainty propagation.

Gainey, Brian, Longtin, Jon P., Lawler, Benjamin

The Physical and Chemical Effects of Fuel on Gasoline Compression Ignition

2019-01-115004/02/2019

In the engine community, gasoline compression ignition (GCI) engines are at the forefront of research and efforts are being taken to commercialize an optimized GCI engine in the near future. GCI engines are operated typically at Partially Premixed Combustion (PPC) mode as it offers better control of combustion with improved combustion stability. While the transition in combustion homogeneity from convectional Compression Ignition (CI) to Homogenized Charge Compression Ignition (HCCI) combustion via PPC has been comprehensively investigated, the physical and chemical effects of fuel on GCI are rarely reported at different combustion modes. Therefore, in this study, the effect of physical and chemical properties of fuels on GCI is investigated. In-order to investigate the reported problem, low octane gasoline fuels with same RON = 70 but different physical properties and sensitivity (S) are chosen. Fuels with comparable sensitivity and RON are chosen to study the impact of physical

Vallinayagam, R., Hlaing, Ponnya, AlRamadan, Abdullah S., An, Yanzhao, Sim, Jaeheon, Chang, Junseok, Johansson, Bengt

Engine-Aftertreatment in Closed-Loop Modeling for Heavy Duty Truck Emissions Control

2019-01-098604/02/2019

An engine-aftertreatment computational model was developed to support in-loop performance simulations of tailpipe emissions and fuel consumption associated with a range of heavy-duty (HD) truck drive cycles. For purposes of this study, the engine-out exhaust dynamics were simulated with a combination of steady-state engine maps and dynamic correction factors that accounted for recent engine operating history. The engine correction factors were approximated as dynamic first-order lags associated with the thermal inertia of the major engine components and the rate at which engine-out exhaust temperature and composition vary as combustion heat is absorbed or lost to the surroundings. The aftertreatment model included catalytic monolith components for diesel exhaust oxidation, particulate filtration, and selective catalytic reduction of nitrogen oxides (NOx) with urea. Both the engine and aftertreatment models have been calibrated with dynamometer measurements from a commercial 2010

Gao, Zhiming, Deter, Dean, Smith, David, Pihl, Josh, Daw, C. Stuart, Parks, James

Understanding HCCI Combustion in a Free Piston Engine with a Multi-Zone, Control-Mass Model with Thermal Stratification and Chemical Kinetics

2019-01-095804/02/2019

Homogeneous Charge Compression Ignition (HCCI) is a combustion concept with the potential for future clean and efficient automotive powertrains. In HCCI, the thermal stratification has been proven to play an important role in dictating the combustion process, mainly caused by heat transfer to the wall during compression. In this study, a multi-zone, control-mass model with thermal stratification and chemical kinetics was developed to simulate HCCI combustion. In this kind of model, the initial conditions and the zonal heat transfer fraction distribution are critical for the modeling accuracy and usually require case-by-case tuning. Instead, in this study, the Thermal Stratification Analysis (TSA) methodology is used to generate the zonal heat transfer fraction distribution from experimental HCCI data collected on a fired, metal engine. It is found that this normalized distribution determined by the TSA methodology from one experimental operating condition is wide-ranging enough to be

Zhou, Yingcong, Gainey, Brian, Hariharan, Deivanayagam, Lawler, Benjamin, Mamalis, Sotirios

Thermal Efficiency Improvement and its Mechanism at Low Load Conditions in Semi-Premixed Diesel Combustion with Twin Peak Shaped Heat Release

2019-01-115304/02/2019

Semi-premixed diesel combustion with a twin peak shaped heat release with the two-stage fuel injection (twin combustion) has the potential to establish efficient, low emission, and low noise operation. However, with twin combustion at low loads the indicated thermal efficiencies are poorer than at medium loads due to the lower combustion efficiencies. In this report, to increase the combustion efficiencies at low loads, the thermal efficiency related parameters were investigated in a 0.55 L single cylinder diesel engine. The results show that the indicated thermal efficiency improves with increases in the intake gas temperatures at low loads. However, at the higher loads where the combustion efficiencies are somewhat higher the indicated thermal efficiencies decrease with increases in the intake gas temperatures due to increases in the cooling losses. At the low load condition below 300 kPa IMEP, the indicated thermal efficiency is higher and the combustion noise is lower in the twin

Inaba, Kazuki, Masuko, Yosuke, Zhang, Yanhe, Kobashi, Yoshimitsu, Shibata, Gen, Ogawa, Hideyuki

Numerical Analysis on the Effect of Piston Bowl Geometry in Gasoline-Diesel Dual-Fuel Combustion

2019-01-116404/02/2019

As emissions regulations become stricter, a variety of advanced combustion concepts that can reduce emissions with a higher thermal efficiency have been suggested. Dual-fuel combustion is one of the alternatives that has both premixed and non-premixed combustion characteristics. Knowing the effects of the mixture formation in dual-fuel combustion is important because it determines the ignition location and the following combustion phase. Hence, a thorough investigation on the related factors, such as the engine hardware or fuel spray, is required. Meanwhile, Computational Fluid Dynamics (CFD) is a good technique to visualize the in-cylinder phenomena and enables quantitative investigations into the detailed combustion characteristics. In this paper, a 3-dimensional CFD simulation was used to investigate the effects of the mixture formation in dual-fuel combustion. The combustion model consists of two parts. The Representative Interactive Flamelet (RIF) model was used to solve the auto

Moon, Sunyoung, Kim, Gyujin, Chu, Sanghyun, Kang, Jaegu, Min, Kyoungdoug, Choi, Hoimyung, Ha, Taehun

TSCI with Wet Ethanol: An Investigation of the Effects of Injection Strategy on a Diesel Engine Architecture

2019-01-114604/02/2019

Thermally Stratified Compressions Ignition (TSCI) is a new advanced, low temperature combustion concept that aims to control the thermal stratification in the cylinder in order to control the heat release process in a lean, compression-ignition combustion mode. This work uses “wet ethanol”, a mixture of 80% ethanol and 20% water by mass, to increase thermal stratification beyond what naturally occurs, via evaporative cooling of a split direct injection. TSCI with wet ethanol has previously shown the potential to increase the high-load limit when compared to HCCI. The experiments conducted in this paper aim to fundamentally understand the effect that injection strategy has on the heat release process in TSCI. TSCI employs a split-injection strategy in which an injection during the intake stroke allows the majority of the fuel to premix with the air and an injection during the compression stroke introduces the desired level of thermal stratification to control the heat release rate. A

Gainey, Brian, Yan, Ziming, Gohn, James, Rahimi Boldaji, Mozhgan, Lawler, Benjamin

Triple Injection Strategies for Gasoline Compression Ignition (GCI) Combustion in a Single-Cylinder Small-Bore Common-Rail Diesel Engine

2019-01-114804/02/2019

Implementing triple injection strategies in partially premixed charge-based gasoline compression ignition (GCI) engines has shown to achieve improved engine efficiency and reduced NOx and smoke emissions in many previous studies. While the impact of the triple injections on engine performance and engine-out emissions are well known, their role in controlling the mixture homogeneity and charge premixedness is currently poorly understood. The present study shows correspondence between the triple injection strategies and mixture homogeneity/premixedness through the experimental tests of second/third injection proportion and their timing variations with an aim to explain the observed GCI engine performance and emission trends. The experiments were conducted in a single cylinder, small-bore common-rail diesel engine fuelled with a commercial gasoline fuel of 95 research octane number (RON) and running at 2000 rpm and 830 kPa indicated mean effective pressure conditions. While the first

Liu, Xinyu, Goyal, Harsh, Kook, Sanghoon, Ikeda, Yuji

A Visual Investigation of CFD-Predicted In-Cylinder Mechanisms That Control First- and Second-Stage Ignition in Diesel Jets

2019-01-054304/02/2019

The long-term goal of this work is to develop a conceptual model for multiple injections of diesel jets. The current work contributes to that effort by performing a detailed modeling investigation into mechanisms that are predicted to control 1st and 2nd stage ignition in single-pulse diesel (n-dodecane) jets under different conditions. One condition produces a jet with negative ignition dwell that is dominated by mixing-controlled heat release, and the other, a jet with positive ignition dwell and dominated by premixed heat release. During 1st stage ignition, fuel is predicted to burn similarly under both conditions; far upstream, gases at the radial-edge of the jet, where gas temperatures are hotter, partially react and reactions continue as gases flow downstream. Once beyond the point of complete fuel evaporation, near-axis gases are no longer cooled by the evaporation process and 1st stage ignition transitions to 2nd stage ignition. At this point, for the positive ignition dwell

Hessel, Randy, Reitz, Rolf, Musculus, Mark

Effects of Compression Ratio and Water Vapor Induction on the Achievable Load Limits of a Light Duty Diesel Engine Operated in HCCI Mode

2019-01-096204/02/2019

Among the various Low Temperature Combustion (LTC) strategies, Homogeneous Charge Compression Ignition (HCCI) is most promising to achieve near zero oxides of nitrogen (NOx) and particulate matter emissions owing to higher degree of homogeneity and elimination of diffusion phase combustion. However, one of its major limitations include a very narrow operating load range owing to misfire at low loads and knocking at high loads. Implementing HCCI in small light duty air cooled diesel engines pose challenges to eliminate misfire and knocking problems owing to lower power output and air cooled operation, respectively. In the present work, experimental investigations are done in HCCI mode in one such light duty production diesel engine most widely used in agricultural water pumping applications. An external mixture preparation based diesel HCCI is implemented in the test engine by utilizing a high-pressure port fuel injection system, a fuel vaporizer and an air preheater. With an existing

M, Murugesa Pandian, Krishnasamy, Anand

Modeling the Effect of Thermal Barrier Coatings on HCCI Engine Combustion Using CFD Simulations with Conjugate Heat Transfer

2019-01-095604/02/2019

Thermal barrier coatings with low conductivity and low heat capacity have been shown to improve the performance of homogeneous charge compression ignition (HCCI) engines. These coatings improve the combustion process by reducing heat transfer during the hot portion of the engine cycle without the penalty thicker coatings typically have on volumetric efficiency. Computational fluid dynamic simulations with conjugate heat transfer between the in-cylinder fluid and solid piston of a single cylinder HCCI engine with exhaust valve rebreathing are carried out to further understand the impacts of these coatings on the combustion process. For the HCCI engine studied with exhaust valve rebreathing, it is shown that simulations needed to be run for multiple engine cycles for the results to converge given how sensitive the rebreathing process is to the residual gas state. The effect of thermal barrier coatings on the piston surface is explored using the properties of Yttria-Stabilized Zirconia

Killingsworth, Nick, Powell, Tom, O'Donnell, Ryan, Filipi, Zoran, Hoffman, Mark

Experimental Investigations to Extend the Load Range of Premixed Charge Compression Ignited Light Duty Diesel Engine through Fuel Modifications

2019-01-095304/02/2019

Premixed Charge Compression Ignition (PCCI) is one of the most promising low temperature combustion (LTC) strategies to achieve near zero oxides of nitrogen (NOx) and particulate matter (PM) emissions along with higher thermal efficiency. One of the major problems in diesel PCCI is a narrow operating load range because of very early ignition and knocking combustion at higher loads owing to higher reactivity of diesel fuel. Further, low volatile diesel resist vaporization, resulting in fuel spray wall wetting and higher unburned emissions in PCCI. Thus, high reactivity and low volatility of diesel fuel make it not suitable for PCCI combustion. The present work attempts to address these limitations, by blending diesel with high volatile and low reactive fuels, viz. gasoline and butanol at 10% and 20% blend levels by volume. A production light duty air cooled diesel engine most widely used in agricultural water pumping applications is modified to run in PCCI mode by replacing an existing

Gupta, Saurabh K, Krishnasamy, Anand

Φ-Sensitivity for LTGC Engines: Understanding the Fundamentals and Tailoring Fuel Blends to Maximize This Property

2019-01-096104/02/2019

Φ-sensitivity is a fuel characteristic that has important benefits for the operation and control of low-temperature gasoline combustion (LTGC) engines. A fuel is φ-sensitive if its autoignition reactivity varies with the fuel/air equivalence ratio (φ). Thus, multiple-injection strategies can be used to create a φ-distribution that leads to several benefits. First, the φ-distribution causes a sequential autoignition that reduces the maximum heat release rate. This allows higher loads without knock and/or advanced combustion timing for higher efficiencies. Second, combustion phasing can be controlled by adjusting the fuel-injection strategy. Finally, experiments show that intermediate-temperature heat release (ITHR) increases with φ-sensitivity, increasing the allowable combustion retard and improving stability. A detailed mechanism was applied using CHEMKIN to understand the chemistry responsible for φ-sensitivity. For fuels with NTC behavior, φ-sensitivity is greatest in the NTC region

Lopez Pintor, Dario, Dec, John, Gentz, Gerald

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