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Technical Paper

Experimental Analysis of Force Recovery and Response Time using Strain Measurement Sensors in Stress Wave Force Balance

2024-06-01
2024-26-0451
Severe problem of aerodynamic heating and drag force are inherent with any hypersonic space vehicle like space shuttle, missiles etc. For proper design of vehicle, the drag force measurement become very crucial. Ground based test facilities are employed for these estimates along with any suitable force balance as well as sensors. There are many sensors (Accelerometer, Strain gauge and Piezofilm) reported in the literature that is used for evaluating the actual aerodynamic forces over test model in high speed flow. As per previous study, the piezofilm also become an alternative sensor over the strain gauges due to its simple instrumentation. For current investigation, the piezofilm and strain gauge sensors have mounted on same stress force balance to evaluate the response time as well as accuracy of predicted force at the same instant. However, these force balance need to be calibrated for inverse prediction of the force from recorded responses.
Technical Paper

Ducted Fuel Injection: Confirmed re-entrainment hypothesis

2024-04-09
2024-01-2885
Testing of ducted fuel injection (DFI) in a single-cylinder engine with production-like hardware previously showed that simply adding a duct structure increased soot emissions at the full load, rated speed operating point. In the authors’ 2021 SAE paper, which reported these findings, it was hypothesized that the DFI flame, which is faster than a conventional diesel combustion (CDC) flame, and has a shorter distance to travel, was being re-entrained into the on-going injection around the lift-off length, thus reducing air entrainment into the on-going injection. The engine operating condition and the engine combustion chamber geometry were duplicated in a constant pressure vessel. The experimental setup used a 3D piston section combined with a glass fire deck allowing for a comparison between a CDC flame and a DFI flame via high-speed imaging. Testing clearly confirmed the detrimental effect of the DFI flame re-entrainment hypothesis presented in the previous on-engine work.
Technical Paper

Evaluating the effects of an Electrically Assisted Turbocharger on scavenging control for an Opposed Piston Two Stroke (OP2S) compression ignition engine

2024-04-09
2024-01-2388
Opposed piston two-stroke (OP2S) diesel engines have demonstrated a reduction in engine-out emissions and increased efficiency compared to conventional four-stroke diesel engines. Due to the higher thermal efficiency and absence of a cylinder head, the heat transfer loss to the coolant is lower near the ‘Top Dead Center’. The selection and design of the airpath are pivotal in realizing the benefits of the OP2S engine architecture. Like any two-stroke diesel engine, the scavenging process and the composition of the internal residuals are predominantly governed by the pressure differential between the intake and the exhaust ports. Moreover, a significant portion of the work involved in pumping air is carried out externally to the engine cylinder which needs to be accounted for when calculating brake efficiencies.
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

Closed Track Testing To Assess Prototype Level-3 Autonomous Vehicle Readiness for Public Road Deployment

2024-04-09
2024-01-1976
Most of the Automated Driving Systems (ADS) technology development is targeting urban areas; there is still much to learn about how ADS will impact rural transportation. The DriveOhio team deployed level-3 ADS-equipped prototype vehicles in rural Ohio with the goal of discovering technical challenges for ADS deployment in such environments. However, before the deployment on public roads, it was essential to test the ADS-equipped vehicle for their safety limitations. At Transportation Research Center (TRC) proving grounds, we tested one such prototype system on a closed test track with soft targets and robotic platforms as surrogates for other road users. This paper presents an approach to safely conduct testing for ADS prototype and assess its readiness for public road deployment. The main goal of this testing was to identify a safe Operational Design Domain (ODD) of this system by gaining better understanding of the limitations of the system.
Technical Paper

Effect of in-cylinder flow motion on fuel-air mixture formation in a medium-duty DI-SI H2 engine: an experimentally supported CFD study

2024-04-09
2024-01-2117
The increased utilization of batteries and fuel-cells for powering electric applications, as well as bio- and e-fuels into internal combustion engines are seen as options to lower the carbon footprint of industry and transportation sectors. When high power outputs and fast refuelling are requisites, H2 ICEs may be a relevant choice. Applications include electricity conversion within a genset or mechanical energy in a vehicle. Within this framework, a John Deere 4045 Diesel engine converted to a H2 single-cylinder is studied at relevant operating conditions for the mentioned use cases, which pose high torque and power output requirements. The modified engine integrates a Phinia DI-CHG 10 outward-opening H2 injector instead of the Diesel unit, as well as a spark-plug rather than the standard glow-plug.
Technical Paper

The new China Automotive Technology and Research Center aerodynamic-acoustic and climatic wind tunnels

2024-04-09
2024-01-2541
The China Automotive Technology and Research Center (CATARC) has completed two new wind tunnels at its test center in Tianjin, China: an aerodynamic/aeroacoustic wind tunnel (AAWT), and a climatic wind tunnel (CWT). The AAWT incorporates design features to provide both a very low fan power requirement, 3.1 MW at 250 km/hr with a 28 m2 test section, and a very low background noise, 58.2 dB(A) at 150 km/h, putting it amongst the quietest in the automotive world. These features are also combined with high flow quality, a full boundary layer control system and 5-belt rolling road (producing a 5 mm block height boundary layer profile), an automated traversing system, and a complete acoustic measurement system including a 3-sided microphone array. The CWT, located in the same building as the AAWT, has a flexible nozzle to deliver 250 km/h with an 8.25 m2 nozzle, and 130 km/h with a 13.2 m2 nozzle.
Technical Paper

Benchmarking of Neural Netowrk Methodologies for Piston Thermal Model Calibration

2024-04-09
2024-01-2598
During the design phase of engine components, it is important to have accurate model predictions of the temperature field in order to adequately capture temperature-dependent material behavior and thermal gradients that greatly influence the component fatigue life. In pistons, the heat transfer analysis depends on backside heat transfer boundary conditions (BCs), which are difficult to estimate. One method to circumvent this problem is to collect experimental temperature data and calibrate the backside heat transfer BCs in a computer model to this data. Previously, a traditional Bayesian calibration methodology has been successfully applied to calibrate these backside BCs in piston heat transfer models to experimental data. This method leverages the use of Gaussian process surrogate modeling of the computer model and then performing Bayesian inference on the unknown boundary conditions, which can be computationally expensive.
Technical Paper

Efficient Fatigue Performance Dominated Optimization Method for Heavy-Duty Vehicle Suspension Brackets under Proving Ground Load

2024-04-09
2024-01-2256
Lightweight design is a key factor in general engineering practice; however, it often conflicts with fatigue durability. In this study, a methodology to enhance the efficiency of fatigue optimization is proposed, with a case study on heavy-duty vehicle suspension brackets illustrating the approach. This case study is based on random load data collected from fatigue durability tests in proving grounds, and fatigue failures of the heavy-duty vehicle suspension brackets were observed and recorded during the tests. An integrated approach to multi-objective fatigue optimization was introduced by employing multi-axial time-domain fatigue analysis under random loads combined with the non-dominated sorting genetic algorithm II with archives. While evaluating fatigue life within optimization loops, particularly for multi-axial random load fatigue in the time domain, is time-intensive, this study introduces modifications to improve computational efficiency.
Technical Paper

NHTSA’s Evaluation of Glazing Performance Tests

2024-04-09
2024-01-2491
FMVSS No. 205, “Glazing Materials,” uses impact test methods specified in ANSI/SAE Z26.1-1996. NHTSA’s Vehicle Research and Test Center initiated research to evaluate a subset of test methods from ANSI Z26.1-1996 including the 227 gram ball, shot bag, and dart impact tests, and the fracture test. Additional research was completed to learn about potential changes to tempered glass strength due to the ceramic paint area (CPA), and to compare the performance of twelve by twelve inch flat sample and full-size production parts. Glass evaluated included tempered rear quarter, sunroof and backlight glazing and laminated windshield glazing. Samples with a paint edge were compared to samples without paint, and to production parts with and without paint in equivalent impact tests. A modified shot bag with stiffened sidewalls was compared to the ANSI standard shot bag. The fracture test comparison included evaluating the ANSI Z26.1 punch location and ECE R43 punch location.
Technical Paper

Elucidation of Deteriorating Oil Consumption Mechanism due to Piston Top Ring Groove Wear

2024-04-09
2024-01-2269
During engine durability testing, the piston and piston ring are used in harsh contact environments, causing the piston ring groove to experience significant wear, leading to significant development costs for countermeasures. To ensure functional feasibility due to wear on the piston top ring groove (hereinafter referred to as the ring groove), traditional methods of evaluating function through practical engine durability tests were the only option, presenting challenges in determining the wear limit value itself. Therefore, the judgment criteria had to have a margin for functional assurance purposes, although the mechanism of ring groove wear has been revealed in past research. To establish judgment criteria for optimal design, it was necessary to understand the effects and mechanism of ring groove wear. This study clarified the functional impact and occurrence mechanism of upper-surface wear on the ring groove through two experiments.
Technical Paper

Modeling and time discrete characteristics analysis of the oil filling process of wet clutch for a specialized vehicle’s automatic transmission

2024-04-09
2024-01-2284
The automatic transmission of a specialized vehicle experienced the issue of unstable oil charge time due to the significant variability of related parameters and the non-linear trend of individual product parameter changes over time. To investigate the underlying causes of this phenomenon and the improved oil charge effect, a detailed model of the clutch oil charge process during gear shifting was established in this paper, which included dynamic models of components such as the hydraulic system, clutch, proportional valve, and pumps. The influence of parameters such as orifice diameter, piston gap, and oil filling flow rate on the system response was taken into account. Dynamic simulations were conducted to study the impact of these parameters on the clutch oil charge time. Additionally, physical experiments were performed using a test bench to provide a comparison with the simulation results.
Technical Paper

Improving the Performance of Diesel Engines by Bore Profile Control under Operating Conditions

2024-04-09
2024-01-2832
A cylinder block involves bore deformation due to assembling stress of cylinder head and thermal stress. This distortion is found to be the cause of the exacerbation of piston skirt friction and piston slap. This article presents a numerical and experimental study of the effect of an optimized bore profile on engine performance. A friction analysis of 3-dimentional elastohydrodynamic was applied for an estimation of the piston skirt friction. A cylinder bore with barrel shape under the part load operation point was assumed as an optimal bore profile in terms of piston skirt friction without compromising piston slap. From the simulation study, it was found that the piston secondary motion just after firing top dead center can be mitigated by narrower piston – bore clearance at upper position of the cylinder.
Technical Paper

The Development and Validation of a Novel Two-Parameter Controlled Tribometer for Durability Analysis of the Piston Ring-Cylinder Tribopair in IC Engines

2024-04-09
2024-01-2067
The wear of the piston ring-cylinder liner system in gasoline engines is inevitable and significantly impacts fuel economy. Utilizing a custom-built linear reciprocating tribometer, this study assesses the wear resistance of newly developed engine cylinder coatings. The custom device offers a cost-effective means for tribological evaluation, optimizing coating process parameters with precise control over critical operational factors such as normal load and sliding frequency. Unlike conventional commercial tribometers, it ensures a more accurate simulation of the engine cylinder system. However, existing research lacks a comprehensive comparative analysis and procedure to establish precision limits for such modified devices. This study evaluates the custom tribometer's repeatability compared to a commercial wear-testing instrument, confirming its potential as a valuable tool for advanced wear testing on engine cylinder samples.
Technical Paper

Evaluation of Uncoated Gasoline Particulate Filter Performance for US EPA MY27+ Particulate Mass Emissions Regulation

2024-04-09
2024-01-2383
The gasoline particulate filter (GPF) represents a practical solution for particulate emissions control in light-duty gasoline-fueled vehicles. It is also seen as an essential technology in North America to meet the upcoming US EPA tailpipe emission regulation, as proposed in the “Multi-pollutant Rule for Model Year 2027”. The goal of this study was to introduce advanced, uncoated GPF products and measure their particulate mass (PM) reduction performance within the existing US EPA FTP vehicle testing procedures, as detailed in Code of Federal Regulations (CFR) part 1066. Various state-of-the-art GPF products were characterized for their microstructure properties and lab-bench performance for pressure drop and filtration efficiency, were then subjected to an EPA-recommended 2000mile on-road break-in, and finally were tested on an AWD vehicle chassis-dyno emissions test cell at both 25C and -7C ambient conditions.
Technical Paper

Next Generations of Gasoline Particulate Filters for Catalyzed Applications

2024-04-09
2024-01-2384
Gasoline particulate filters (GPF) have become a standard aftertreatment component in Europe, China, and since recently, India, where particulate emissions are based on a particle number (PN) standard. The anticipated evolution of regulations in these regions towards future EU7, CN7, and BS7 standards further enhances the needs with respect to the filtration capabilities of the GPFs used. Emission performance has to be met over a broader range in particle size, counting particles down to 10nm, and over a broader range of boundary conditions. The requirements with respect to pressure drop, aiming for as low as possible, and durability remain similar or are also enhanced further. To address these future needs new filter technologies have been developed. New technologies for uncatalyzed GPF applications have been introduced in our previous publications.
Technical Paper

Piston geometries impact on Spark-Ignition light-duty hydrogen engine

2024-04-09
2024-01-2613
The European Union aims to be climate neutral by 2050 and requires the transportation sector to reduce their emissions by 90%. The deployment of H2ICE to power vehicles is one of the solutions proposed. Indeed, H2ICEs in vehicles can reduce local pollution, reduce global emissions of CO2 and increase efficiency. Although H2ICEs could be rapidly introduced, investigations on hydrogen combustion in internal combustion engines are still required. This paper aims to experimentally compare a flat piston and a bowl piston in terms of performances and emissions. For the performances, experiments were performed with the help of a single cylinder Diesel engine which has been modified. In particular, a center direct injector dedicated to H2 injection and a side-mounted spark plug were installed, and the compression ratio was reduced to 12.7:1. For the emissions, several exhaust gas measurement systems were used to monitor NO, NO2, N2O and H2.
Technical Paper

Conjugate Heat Transfer Analysis of an i-4 Engine including Pistons, Liners, Block, Heads, Water Cooling Jacket, and Oil Cooling Jets

2024-04-09
2024-01-2696
Internal combustion engine (IC engine) vehicles are commonly used for transportation due to their versatility. Due to this, efficiency in design process of IC engines is critical for the industry. To assess performance capabilities of an IC engine, thermal predictions are of utmost consequence. This study describes a computational method based on unsteady Reynolds-averaged Navier–Stokes equations that resolves the gas–liquid interface to examine the unsteady single phase/multiphase flow and heat transfer in a 4-cylinder Inline (i-4) engine. The study considers all important parts of the engine i.e., pistons, cylinder liners, head, block etc. The study highlights the ease of capturing complex and intricate flow paths with a robust mesh generation tool in combination with a robust high-fidelity interface capturing VOF scheme to resolve the gas-liquid interfaces.
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