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Technical Paper

Numerical Assessment of Tribological Performance of Different Llow Viscosity Engine Oils in a 4-Stroke CI Light-Duty ICE

2022-03-29
2022-01-0321
Decreasing fuel consumption in Internal Combustion Engines (ICE) is a key target for engine developers in order to achieve the CO2 emissions limits during a standard cycle. In this context, reduction of engine friction can help meet those targets. The use of Low Viscosity Engine Oils (LVEOs), which is currently one of the avenues to achieve such reductions, is studied in this manuscript through a validated numerical simulation model that predicts the friction of the engine’s piston-cylinder unit, journal bearings and camshaft. These frictional power losses are obtained for four different lubricant formulations which differ in their viscosity grades and design. Results show a maximum friction savings of up to 6% depending on the engine operating condition, where the major reductions come from hydrodynamic-dominated components such as journal bearings, despite an increase in friction in boundary-dominated components such as the piston-ring assembly.
Technical Paper

Laser-Based In-Exhaust Gas Sensor for On-Road Vehicles

2022-03-29
2022-01-0535
Indrio Technologies has developed a novel on-board sensor, named Ignis, for detecting oxides of nitrogen (NOx) and ammonia (NH3) in diesel exhaust streams with sensitivities and molecular specificity unmet by existing technologies. This is a key technological need for diesel engine manufacturers, who face difficulty in precisely controlling their exhaust aftertreatment systems due to the lack of widely deployable sensors capable of differentiating between NOx, NH3 and other species in the exhaust stream. The successful incorporation of the proposed sensor can result in greater fuel efficiency improvements while matching new stringent 2027 California and 2030 EPA NOx emissions standards. Once the product has reached deep market penetration, the fleet-wide fuel economy improvements and NOx emissions reductions enabled by this product will lead to reduced carbon emissions and healthier air with lower amounts of NOx-induced smog, ground-level ozone, and acid rain.
Technical Paper

A Review of Current Understanding of the Underlying Physics Governing the Interaction, Ignition and Combustion Dynamics of Multiple-injections in Diesel Engines

2022-03-29
2022-01-0445
This work is intended to be a comprehensive technical review of existing literature and a synthesis of current understanding of the governing physics behind the interaction of multiple fuel injectio ns, ignition and combustion behavior of multiple-injections in diesel engines. Multiple-injection is a widely adopted operating strategy applied in modern compression-ignition engines, which involves various combinations of small pre-injections and post-injections of fuel before and after the main injection and splitting the main injection into multiple smaller injections. This strategy has been conclusively shown to improve fuel economy in diesel engines while achieving simultaneous NOx, soot, and combustion noise reduction in addition to a reduction in the emissions of unburned hydrocarbons and CO by preventing fuel wetting and flame quenching at the piston wall.
Technical Paper

Development and validation of an EHN mechanism for fundamental and applied chemistry studies

2022-03-29
2022-01-0455
Autoignition enhancing additives have been used for years to enhance the ignition quality of diesel fuel, with 2-ethylexyl nitrate (EHN) being the most common additive. EHN also enhances the autoignition reactivity of gasoline, which has advantages for some low-temperature combustion techniques, such as Sandia’s Low-Temperature Gasoline Combustion (LTGC) with Additive-Mixing Fuel Injection (AMFI). LTGC-AMFI is a new high-efficiency and low-emissions engine combustion process based on supplying a small, variable amount of EHN into the fuel for better engine operation and control. However, the mechanism by which EHN interacts with the fuel remains unclear. In this work, a chemical-kinetic mechanism for EHN was developed and implemented in a detailed mechanism for gasoline fuels. The combined mechanism was validated against shock-tube experiments with EHN-doped n-heptane and HCCI engine data for EHN-doped regular E10 gasoline. Simulations showed a very good match with experiments.
Technical Paper

Experimental Evaluation of Methane-Hydrogen Mixtures for Enabling Stable Lean Combustion in Spark-Ignition Engines for Automotive Applications

2022-03-29
2022-01-0471
Economy decarbonization will be one of the main goals for the following years. Research efforts are being focused on reducing carbon-based emissions, by increasing the efficiency of the transport power plants while developing new fuel production methods that reduce the environmental footprint of the refinement process. Consequently, the depletion of conventional fuels derived from petroleum with high carbon content, such as gasoline and diesel, motivated the development of propulsive alternatives for the automotive sector. In this paradigm, methane (CH4) fuel appears as a mid-term solution due to its low carbon content, if compared with traditional fuels, and the low CO2 emissions during its production from renewable sources. However, the intrinsic properties of methane compromise the combustion process, subsequently increasing the emission of CO2.
Technical Paper

Modeling of regeneration dynamics in gasoline particulate filters and sensitivity analysis of numerical solutions

2022-03-29
2022-01-0556
Gasoline Direct-Injection (GDI) engine technology improves vehicle fuel economy toward future targets and simultaneously decreases CO2 emissions. The main drawback of this technology is the increased emission of particulates (when compared to their indirect injection-based technology counterpart). Thus, aftertreatment devices such as Gasoline Particulate Filters (GPFs) are today considered the most promising and practically adoptable solution to limit PM/PN out of GDI exhaust. The particulate filter traps soot particles resulting from fuel combustion and prevents their release into the atmosphere. Soot oxidation (also known as regeneration) is required at regular intervals to clean the filter, maintain a consistent soot trapping efficiency, and avoid the formation of soot plugs in the GPF channel.
Technical Paper

Title: Numerical optimization of the piston bowl geometry and investigation of the key geometric parameters for the dual-mode dual-fuel (DMDF) concept under a wide load range

2022-03-29
2022-01-0782
Focusing on the dual-mode dual-fuel (DMDF) combustion concept, a combined optimization of the piston bowl geometry with the fuel injection strategy was conducted at low, mid, and high loads. By coupling the KIVA-3V code with the enhanced genetic algorithm (GA), a total of 14 parameters including the piston bowl geometric parameters and the injection parameters were optimized with the objective of meeting Euro VI regulations while improving the fuel efficiency. The optimal piston bowl shape coupled with the corresponding injection strategy was summarized and integrated at various loads. Furthermore, the effects of the key geometric parameters were investigated in terms of organizing the in-cylinder flow, influencing the energy distribution, and affecting the emissions. The results indicate that the behavior of the DMDF combustion mode is further enhanced in the aspects of improving the fuel economy and controlling the emissions after the bowl geometry optimization.
Technical Paper

Identifying Factors that Affect Brake Wear PM Emissions During Real-world Test Conditions

2022-03-29
2022-01-0570
Particulate Matter (PM) is one of the world’s most problematic pollutants in terms of harm to environment and human health. It has been found out that PM emission levels are very high during traffic congestion and thus, PM is considered as the primary pollutants in urban areas. Many literatures suggested that PM emitted during braking sequence from both internal combustion engines and electrified vehicles are considered high and could be the major cause of this issue. Many studies regarding to PM from brake wear were done in the pin disc laboratory setup which might not represent real-world driving scenarios. Various studies of on road non-exhaust PM measurement were mostly focused on driving cycles. Parametric studies to identifying factors that affect brake wear during real-world driving scenarios are still needed for more investigations. The current study focuses on identifying factors that affect brake wear particle emissions from an on-road vehicle in real-time measurements.
Technical Paper

Calculation Methods Impact on Real Driving Emissions Particulate Number Emission Evaluation: Moving Average Window in China vs. Raw Mileage Averaged in Europe

2022-03-29
2022-01-0567
In the Real Driving Emissions (RDE) tests, Particulate Number (PN) emission is specifically restricted with a limit as product of the Conformity Factor (CF) and WLTC PN limit 6.0E11 #/km. The CF value is defined as 1.5 in the Europe 6d and 2.1 in the China 6b. Besides the tighter CF value in Europe, the calculation methods that are employed to evaluate the RDE PN emission are also different, i.e. Moving Averaged Window (MAW) according to the China 6b and Raw Mileage Averaged (RMA) according to the Europe 6d RDE package 4. In our previous studies, the “MAW” method was found to be less stringent than the “RMA” method generally, because the window-based “MAW” method could under-estimate the high PN emission generated in the cold start [1]. In fact, for the “MAW” method, the cold start emissions are less counted compared to emissions from the middle of the RDE test. Meanwhile, the weight of each window is impacted by CO2 emission.
Technical Paper

Comparison and analysis of real-driving emissions with different processing methods and driving behaviors from a light-duty gasoline vehicle

2022-03-29
2022-01-0573
Real driving emission (RDE) tests are influenced by factors such as data processing methods, driving behaviors, and environmental conditions. Therefore, being able to effectively identify test influence factors is particularly important for RDE emissions-based calibrations. In order to investigate the correlation between data processing methods, driving behaviors and vehicle emissions, the moving average window (MAW) method and cumulative averaging (CA) method were used to compare and analyze the RDE test data of a light-duty gasoline vehicle under different driving modes in this study. The results showed that in MAW method, carbon monoxide (CO) emissions of urban and total trips calculated by using the front to back window division order were slightly lower compared to the back to front window division order, with an average reduction of 4.68% and 6.33%, respectively. For carbon dioxide (CO2) emissions, the order of window division had the opposite effect as for CO emissions.
Technical Paper

Assessment of the impact of vehicle emissions on air quality changes during COVID-19 lockdown in Bogota, Colombia.

2022-03-29
2022-01-0583
The COVID-19 pandemic has forced governments to implement rigorous containment measures on reduction or cessation of human mobility, transportation and economic activities, to control the spread of the virus. This is considered as a unique opportunity to study the impact of local lockdowns periods, especially, on the vehicle emission levels, and urban air quality in cities with high pollution levels, such as Bogota, Colombia. The first case was confirmed in Colombia on March 6, 2020, since then to prevent its propagation, the government declared a national lockdown starting from March 20 until August 31, 2020. Therefore, this study attempted to analyse the air quality in Bogota by assessing the concentrations of the atmospheric pollutants NO₂, SO₂, O₃, CO, PM₂.₅ and PM₁₀ during the lockdown period and the corresponding concentrations levels during the same period in 2018 and 2019.
Technical Paper

PHEV Energy Management Optimization Based on Multi-Island Genetic Algorithm

2022-03-29
2022-01-0739
The plug-in hybrid electric vehicle (PHEV) gradually moves into the mainstream market with its excellent power and energy consumption control, and has become the research target of many researchers. The energy management strategy of plug-in hybrid vehicles is more complicated than traditional fuel vehicles. Therefore, there are still many problems to be solved in terms of power source distribution and energy saving and emission reduction. This research puts forward a new solution idea and realized it through simulation optimization, which solves the energy consumption and emission problems of PHEV to a certain extent. First, on the basis that MATLAB software has completed the modeling of the key components of the vehicle, the fuzzy controller of the vehicle is established considering the principle of the joint control of the engine and the electric motor.
Technical Paper

Experimental Investigation of Performance of Variable Compression Ratio Engine fueled with Pyrolyzed Plastic Oil and Bio alcohols

2022-03-29
2022-01-0605
Waste Plastics are the main barriers in the rain water percolation into the ground which enhances the improvement in the water table. This study utilizes pyrolised waste plastic oil along with diesel-bioethanol, diesel-biobutanol and butanol to fuel variable compression ratio engine. Initially, various proportions of pyrolised waste plastic oil has been blended with bioethanol-diesel blends (containing 15% of bioethanol),biobutanol-diesel blends (containing 20% biobutanol) and Biobutanol and tested for solubility under 25°C followed by property testing as per the American Society of Testing Materials. The results of the property resting are compared by considering diesel fuel as the base fuel. The results indicate that properties of the blends containing 25% of pyrolised waste plastic oil with bioethanol-diesel blends, 20% of pyrolised waste plastic oil with biobutanol-diesel blends and 35% of pyrolised waste plastid oil with biobutanol are closer to that of diesel.
Technical Paper

A new design for Dedicated Hybrid Transmission (DHT) product platform development solution

2022-03-29
2022-01-0670
With increasing pressure from environment problem for reduction in CO2 emissions and stricter fuel targets from road vehicles, OEM around the globe have to electrification their vehicle range to meet increasingly challenging emission standards in recent years and new transmission technologies are gaining more attention in different main market . The actual and future powertrain development has three major directions in order to reduce or avoid emissions in the transportation sector: Hybrid Vehicles: Hybrid Electric Vehicles (HEV), Plug-in HEV (PHEV) Electric Vehicles (EV); Range Extender Electric Vehicle (REEV); Fuel Cell Electric Vehicles (FCEV), Range Extender FCEV (REFCEV). This paper will presents a new type Hybrid transmission which so called “DHT (Dedicated Hybrid Transmission) “ technology for cost-effective HEVs and PHEVs is to permit the design of very compact automatic transmissions with an integrated high-voltage electric motor on the output side of the transmission.
Technical Paper

On the Modeling of Single-Piston CR Pump

2022-03-29
2022-01-0502
The injection strategy as well as the overall efficiency of the diesel engine are tightly related to the performance of the high-pressure injection pump. The paper deals with the modeling of a latest generation Common Rail injection pump, aiming at the characterization of its performance in terms of volumetric- and torque-efficiency. A lumped parameter approach is adopted; with reference to a commercial pump widely used in the field of light diesel engines, a dynamic model of the piston-cylinder pair is built, taking its mechanical drive, the hydraulic supply and delivery systems into account. Based on in-depth experimental activities that provide the diagrams of pump operation cycles, the lumped-parameter model is validated. Given the current strong interest in the use of alternative fuels that limit CO2 emissions, the pump model has been implemented to simulate, beside the standard diesel, the use of biofuels, and to evaluate their impact on pump performance.
Technical Paper

Thermal Validation Study of AdBlue Melting for Off Highway Vehicles

2022-03-29
2022-01-0560
The process of Selective Catalytic Reduction (SCR) is used to reduce NOx emissions for any vehicle that utilizes diesel fuel in a compression-ignition engine. In SCR, diesel exhaust fluid (DEF) which is a mixture of urea and water is injected into the exhaust line, which reacts with NOx and as a result significantly reduces these emissions and maintains compliance with mandatory environmental standards. The DEF fluid is stored in a DEF tank. Under freezing conditions, the DEF fluid will freeze in the tank. It therefore is essential to have a heating system installed that melts the fluid in the tank. Environmental regulations require that the DEF fluid be completely melted in less than a given time. This is necessary, since while the fluid is frozen, NOX treatment will not be possible leading to pollutants being released to the environment. Traditionally, the time required to completely melt the DEF fluid is evaluated through testing.
Technical Paper

Simulation Research on Ultra-lean Constant-volume Combustion Initiated by Spark-ignited Micro-fuel-jet

2022-03-29
2022-01-0432
In the ultra-lean combustion mode, the combustion temperature is relatively low, which is expected to avoid the high-temperature NOx generation. And it also can use excess air to fully oxidize CO, HC and Soot, to achieve cleaner combustion. But at the same time, ultra-lean combustion also has difficulties in ignition and flame propagation. This paper used CONVERGE to simulate the combustion process and products of a new ultra-lean combustion mode, which ignited the ultra-lean premixed fuel/air mixture with the spark-ignited micro-fuel-jet, in a constant-volume vessel with a 6-hole GDI injector. The differences of combustion processes and products were simulated for two spark-ignition positions including ‘on’ the micro-jet spray and ‘between’ two micro-jet sprays. It was found that the combustion duration (the time for burned-fuel-ratio from 10% to 90%) if igniting ‘on’ the micro-jet spray could be shortened by about 14.3%, and the amount of NOx generated would increase about 21.0%.
Technical Paper

A Comparison of Isobaric and Conventional Diesel Combustion using High-Speed Optical Imaging

2022-03-29
2022-01-0418
Isobaric combustion can achieve higher thermal efficiency, lower heat transfer losses, and NOx emissions compared to conventional diesel combustion (CDC). Previous studies on isobaric combustion provided a detailed analysis of performance/emissions characteristics with a limited emphasis on the fuel-air mixing process, high-temperature reaction, and soot formation zones. In the present study, high-speed imaging of Mie-scattering, CH* chemiluminescence, and soot luminosity were conducted in an optically accessible single-cylinder heavy-duty diesel engine for CDC and isobaric combustion. The fuel used for both the combustion modes is n-heptane, which is a surrogate of diesel fuel. The engine was equipped with a flat-bowl shaped optical piston to allow bottom-view imaging of the combustion chamber. The peak cylinder pressure (PCP) and the fuel mean effective pressure (Fuel MEP) for both the combustion modes are kept as 70 bar and 19 bar, respectively.
Technical Paper

Conceptual model for the start of combustion timing in the range from RCCI to conventional dual fuel

2022-03-29
2022-01-0468
In the challenge to reduce CO2, NOx and PM emissions, the application of natural gas or biogas in engines is a viable approach. In heavy duty and marine, either a conventional dual fuel (CDF), or a reactivity controlled compression ignition (RCCI) approach is feasible on existing diesel engines. In both technologies a pilot diesel injection is used to ignite the premixed natural gas. However, the influence of injection-timing and -pressure on the start of combustion timing (SOC) is opposite between the two. For every single operating point these relations can be explained by a detailed CFD simulation, but an intuitive overall explanation is lacking. This makes it difficult to incorporate both modes into one engine application, using a single controller. In an experimental campaign by the authors, on a medium speed engine, the lowest emissions were found to be very close to the SOC corresponding to the transition from RCCI to CDF.
Technical Paper

Optimization of the operating conditions of a dual CI engine fueled with methanol

2022-03-29
2022-01-0465
Among the new low temperature combustion modes, Reactivity-Controlled Compression Ignition (RCCI) offers a low NOx-soot trade off (keeping a relatively high engine efficiency). Also, RCCI permits the introduction of a renewable fuel with a lower CO2 direct emission such as short-chains alcohols. For this work, methanol and diesel fuel were used as low and high reactivity fuels, respectively. A 1.3 L single-cylinder engine, with a cylinder volume usual in medium- and heavy-duty truck and bus engines, was used in this work. The engine was operated at an engine speed of 1600 rpm and 25% load (representing one of the 13-mode test on medium duty trucks), which results in an indicated mean effective pressure of 5.2 bar. The effects of methanol substitution ratio (MSR) at 20 and 35% on performance and pollutant emissions was investigated and compared to conventional diesel combustion (CDC).
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