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Technical Paper

From Idle to 7.5 bar IMEPg – Using Fuel Stratification to Control LTGC with Next-Cycle Capability

2024-04-09
2024-01-2821
Low-temperature gasoline combustion (LTGC) engines can provide high efficiencies with very low NOx and soot emissions, but rapid control of the combustion timing remains a challenge. Partial Fuel Stratification (PFS) was demonstrated to be an effective approach to control combustion in LTGC engines. PFS is produced by a double direct injection strategy with most of the fuel injected early in the cycle and the remainder of the fuel supplied by a second injection at a variable time during the compression stroke to vary the amount of stratification. Adjusting the stratification changes the combustion phasing, and this can be done on cycle-to-cycle basis by adjusting the injection timing. In this paper, the ability of PFS to control the combustion during wide engine load sweeps is assessed for regular gasoline and gasoline doped with 2-ethylhexyl nitrate (EHN). For PFS, the load control range is limited by combustion instability and poor combustion efficiency at low loads.
Technical Paper

Proactive Battery Energy Management using Navigation Information

2024-04-09
2024-01-2142
In this paper, a control strategy for state of charge (SOC) allocation using navigation data for Hybrid Electric Vehicle (HEV) propulsion systems is proposed. This algorithm dynamically defines and adjusts a SOC target as a function of distance travelled on-line, thereby enabling proactive management of the energy store in the battery. The proposed approach incorporates variances in road resistance and adheres to geolocation constraints, including ultra-low emission zones (uLEZ). The anticipated advantages are particularly pronounced during scenarios involving extensive medium-to-long journeys characterized by abrupt topological changes or the necessity for exclusive electric vehicle (EV) mode operation. This novel solution stands to significantly enhance both drivability and fuel economy outcomes.
Technical Paper

Light Duty engine performance characteristics with Dimethyl Ether and Propane

2024-04-09
2024-01-2126
Paper documents the performance characteristics of a compression ignition HYUNDAI 2.2L engine operating with Dimethyl Ether (DME) and Propane mixtures. The engine features a high-pressure common rail fuel injection system designed to operate with DME and Propane. The main component of the fuel system is a high-pressure pump that incorporates an electronic inlet metering valve commanded on a crank angled base to control the rail pressure. The pump, which requires no pressure regulator, provides the flow needed to the injectors without flow returning to the inlet. Tests are carried out at injection pressures from 300bar to 1000bar, and the engine ECU is aided with the use of an Engine Controller High speed Oversight unit (ECHO) to provide combustion phasing control and improved cylinder-to-cylinder uniformity, providing improved optimization over the testing effort.
Technical Paper

Impact of Injection Valve Condition on Data-driven Prediction of Key Combustion Parameters Based on an Intelligent Diesel Fuel Injector for Large Engine Applications

2024-04-09
2024-01-2836
The advent of digitalization opens up new avenues for advances in large internal combustion engine technology. Key engine components are becoming "intelligent" through advanced instrumentation and data analytics. By generating value-added data, they provide deeper insight into processes related to the components. In addition, these data form the basis for novel condition monitoring, predictive maintenance and controls approaches. Changes to the intelligent component’s operational characteristics due to wear or faults pose a particular challenge for developers of such approaches for later series application. A previous study has already demonstrated that an intelligent common rail diesel fuel injection valve for large engine applications in combination with machine learning allows reliable prediction of key combustion parameters such as maximum cylinder pressure, combustion phasing and indicated mean effective pressure.
Technical Paper

Post-Oxidation Phenomena as a Thermal Management Strategy for Automotive After-Treatment Systems: Assessment by means of 3D-CFD Virtual Development

2024-04-09
2024-01-2629
The target of the newly and future automotive emission regulations is to promote a fast transition to near-zero emission vehicles. As such, the range of ambient and operating conditions tested in the homologation cycles is broadening. In this context, the proposed work aims to thoroughly investigate the potential of post-oxidation phenomena in reducing the light-off time of a conventional three-way catalyst. The study is carried out on a turbocharged four-cylinder gasoline engine by means of experimental and numerical activities. Post oxidation is achieved through the oxidation of unburned fuel in the exhaust line, exploiting a rich combustion and a secondary air injection dedicated strategy. The CFD methodology consists of two different approaches: the former relying on a full-engine mesh, the latter on a detailed analysis of the chemical reactions occurring in the exhaust line.
Technical Paper

CFD Methodology for Torque Converter Clutch Slipping Modeling

2024-04-09
2024-01-2150
In torque converters, lockup clutch is used for direct torque transfer from engine to gearbox. Nowadays, earlier lockup engagement is necessary to reduce fuel consumption. It introduces noise & vibration issues in transmission which are solved by clutch slipping. However, the clutch experiences a lot of heat because of earlier engagement which needs to be properly dissipated by ATF oil. To overcome this issue, multi-plate clutches are commonly used for efficient torque transfer and clutch slipping. On the other side, packaging space for torque converters is reducing in vehicle level, especially in hybrid vehicles which reduces the efficient cooling of clutches. So accurate modeling of clutch slipping is necessary to improve the clutch performance and durability of the product. Clutch slipping is a transient phenomenon which involves conjugate heat transfer and rotational flow modeling. There are different ways to model clutch slipping in CFD simulations.
Technical Paper

Value Driving-A Guide to Save Fuel, Travel Time, and Emissions

2024-04-09
2024-01-2851
Instead of Miles per Gallon, a digital display of a new measure of motor vehicle fuel efficiency yields new insight into driving techniques that optimize travel time, fuel expense, and emissions. Dynamic Fuel Cost (DFC) in Dollars ($) per hour relates the change in fuel expense to a change in travel time (d$/dt), the most important measures to motorists. An inexpensive microprocessor communicating through the On-Board Diagnostic (OBD) port of a vehicle collects speed and fuel consumption data, and computes and displays DFC during acceleration, steady speed travel, and deceleration. DFC can be implemented (Patented) as a stand-alone device, a cell phone app, or included in a vehicle infotainment system. The computation and display of DFC reveals new insights into fuel- and time-efficient driving style. during acceleration, steady speed cruising, and deceleration. First, we find that today’s highway speeds are affordable, with DFC similar to current Minimum Wage.
Technical Paper

Energy management strategy for plug-in hybrid vehicles based on model predictive control and local encryption dynamic programming

2024-04-09
2024-01-2781
A model predictive control (MPC) energy management strategy (EMS) coupled with offline dynamic programming (ODP) based on historical average vehicle speed, ODP-MPC, is proposed in this paper. The effectiveness of ODP-MPC is verified using historical traffic flow datasets from the open literature. The simulation results show that ODP-MPC can reduce fuel consumption by 1.1% to 7.3% compared to MPC. Moreover, at the prediction area Hp=3(3s), the fuel consumption of ODP-MPC is only 2.1% higher than that of the DP algorithm. This indicates that ODP-MPC can approximate the theoretical fuel economy. As for the computational effort, the online computation time of ODP-MPC is improved by 6.3%~22.9% compared to MPC, but still less than the 1s time step. Reducing the number of grid cells (m) or increasing the distance step (distf) in offline DP reduces the offline computational cost and the fuel economy of ODP-MPC.
Technical Paper

Numerical Study of an EGR Dilution in a Pre-Chamber Spark Ignited Engine fuelled by Natural Gas

2024-04-09
2024-01-2081
Exhaust gas recirculation (EGR) is a proven strategy for the reduction of NOx emissions in spark ignited (SI) engine and compression ignition engines especially in lean burn conditions where increase thermal efficiency is obtained. The dilution level of the mixture with EGR is in a conventional SI engine limited by the increase of combustion instability (CoV IMEP). A possible method to extend the EGR dilution level and ensure stable combustion is the implementation of an active pre-chamber combustion system. The pre-chamber spark ignited (PCSI) engine enables fast and stable combustion of lean mixtures in the main chamber by utilizing high ignition energy of multiple flame jets penetrating from the pre-chamber to the main chamber. The main feature of an active pre-chamber is the ability to control mixture dilution at the spark plug by adding an injector to the pre-chamber.
Technical Paper

Combustion analysis of Hydrogen-DDF mode based on OH* chemiluminescence images

2024-04-09
2024-01-2367
Hydrogen-diesel dual-fuel combustion processes were studied in a rapid compression and expansion engine (RCEM). In the experiments, the combustion processes were visualized using an optically accessible RCEM that can simulate a single compression and expansion stroke of a diesel engine. A small amount of diesel was injected as a pilot ignition for the hydrogen, with injection pressures of 40, 80, and 120 MPa using a common rail injection system. The amount of diesel injected was varied as 3, 6, and 13 mm3. The hydrogen-air mixture was introduced into the combustion chamber through the intake valve. The amount of hydrogen was manipulated by varying the total excess air ratio(λtotal) at 3 and 4. The RCEM was operated at a constant speed of 900 rpm, and the in-cylinder pressure and temperature at TDC were set at 5 MPa and 700 K, respectively.
Technical Paper

Vehicle Lightweighting Impacts On Energy Consumption Reduction Potential Across Advanced Vehicle Powertrains

2024-04-09
2024-01-2266
The National Highway Traffic Safety Administration (NHTSA) has taken a leading role in overseeing the rulemaking process for Corporate Average Fuel Economy (CAFE) standards. Argonne National Laboratory (ANL), a prominent U.S. Department of Energy (DOE) national laboratory, has developed Autonomie, a comprehensive full-vehicle simulation tool. Autonomie has established itself as an industry-standard tool for assessing vehicle performance, energy consumption, and technology effectiveness. Through an Inter Agency Agreement (IAA), the DOE Argonne Site Office (ASO) and Argonne National Laboratory (ANL) have been entrusted with the task of conducting full-vehicle simulations to support NHTSA's CAFE rulemaking initiatives. This paper introduces an innovative approach that relies on a large-scale simulation process. These simulations encompass standard regulatory driving cycles for various vehicle classes, spanning diverse timeframes.
Technical Paper

Aspects of Engine Lubricant Operating Conditions and Fuel Economy Differentiation; In-Vehicle Comparisons of Standard Internal Combustion Engine with Two Types of Hybrid Electric

2024-04-09
2024-01-2824
Due to the global drive for carbon neutrality, passenger vehicle gasoline engines are transitioning to higher levels of electrification, such as hybrid electric vehicles and plug-in hybrid electric vehicles, HEVs and PHEVs. Compared with conventional internal combustion engines, ICE only operation, the hybrid HEV or plug-in hybrid PHEV engine typically operates for shorter periods, in turn the engine coolant and lubricant temperatures are lower. Conventional internal combustion engines are often able to yield valuable fuel economy benefits by selecting appropriate engine lubricating oils, typically employing reduced viscosity and suitable additives. There are commercial engine tests available for measurement, often in an engine test cell for precision. Steady state testing is also a simplified option. Such efforts require care, as the accurate measurement is technically and practically challenging.
Technical Paper

Evaluation of closed-loop combustion phase optimization for varying fuel compensation and cylinder balancing in a HD SI-ICE

2024-04-09
2024-01-2837
Alternative fuels, such as natural and bio-gas, are attractive options for reducing greenhouse gas emissions from combustion engines. However, the naturally occurring variation in gas composition poses a challenge and may significantly impact engine performance. The gas composition affects fundamental fuel properties such as flame propagation speed and heat release rate. Deviations from the gas composition for which the engine was calibrated result in changes in the combustion phase, reducing engine efficiency and increasing fuel consumption and emissions. However, the efficiency loss can be limited by estimating the combustion phase and adapting the spark timing, which could be implemented favorably using a closed-loop control approach. In this paper, we evaluate the efficiency loss resulting from varying gas compositions and the benefits of using a closed-loop controller to adapt the spark timing to retain the nominal combustion phase.
Technical Paper

Impact of a split-injection strategy on energy-assisted compression-ignition combustion with low cetane number sustainable aviation fuels

2024-04-09
2024-01-2698
The influence of a split-injection strategy on energy-assisted compression-ignition (EACI) combustion of low-cetane number sustainable aviation fuels was investigated in a single-cylinder direct-injection compression-ignition engine using a ceramic ignition assistant (IA). Two low-cetane number fuels were studied: a low-cetane number alcohol-to-jet (ATJ) sustainable aviation fuel (SAF) with a derived cetane number (DCN) of 17.4 and a binary blend of ATJ with F24 (Jet-A fuel with military additives, DCN 45.8) with a blend DCN of 25.9 (25 vol.% F24, 75 vol.% ATJ). A pilot injection mass sweep (3.5-7.0 mg) with constant total injection mass and an injection dwell sweep (1.5-3.0 ms) with fixed main injection timing were performed. Increasing pilot injection mass was found to reduce cycle-to-cycle combustion phasing variability by promoting a shorter and more repeatable combustion event for the main injection with a shorter ignition delay.
Technical Paper

Impact of Advanced Engine Technologies in Energy Consumption Reduction Potentials

2024-04-09
2024-01-2825
The National Highway Traffic Safety Administration (NHTSA) has played a pivotal role in shaping Corporate Average Fuel Economy (CAFE) standards through the rulemaking process. To facilitate this effort, Argonne National Laboratory (ANL), a distinguished U.S. Department of Energy (DOE) national laboratory, has developed Autonomie—a comprehensive full-vehicle simulation tool. Autonomie has emerged as an industry benchmark, serving as an invaluable resource for evaluating vehicle performance, energy usage, and technology efficacy. Under the Inter Agency Agreement (IAA), the DOE Argonne Site Office (ASO) and Argonne National Laboratory (ANL) have undertaken the task of conducting full-vehicle simulations to support NHTSA's CAFE rulemaking endeavors. This paper introduces an innovative approach centered on large-scale simulation processes. These simulations encompass standard regulatory driving cycles, span various vehicle classes, and encompass diverse timeframes.
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