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Technical Paper

Friction Calculations and Validation Measures on an External Component Test Bench of the Piston Pin Bearing under the Influence of Greater Elastic Deformation Caused by a Hydrostatic Bearing

2021-09-05
2021-24-0001
Increasing combustion pressure, low viscosity oils, less oil supply and the increasing stress due to downsizing of internal combustion engines (ICE) lead to higher loads within the bearing. As the mechanical and tribological loads on the piston pin bearings have a direct impact on the service life and function of the overall engine system, it is necessary to develop a robust tribological design approach. Regarding the piston pin bearing of a diesel engine, this study aims to describe the effects of different parameters on a DLC-coated piston pin within the bearing. Therefore, an external engine part test rig, which applies various forces to the connecting rod and measures the torque on a driven pin, is used to carry out validation measurements. The special feature of the test bench is the way the piston is beared. For the first experiments, the piston crown is placed against a plate (plate-bearing); later, this plate-bearing is replaced by a hydrostatic bearing.
Technical Paper

Simulation Study of a Turbocharged Two-Stroke Single Cylinder 425cc SI Engine

2021-09-05
2021-24-0003
An afterburner-assisted turbocharged single-cylinder 425 cc two-stroke SI-engine is described in this simulation study. This engine is intended as a Backup Range Extender (REX) application for heavy-duty battery electric vehicles (BEV) when external electric charging is unavailable. The 425 cc engine is an upscaled version of a 125 cc port-injected engine [26] which demonstrated that the selected technology could provide a specific power level of 400 kW/L and the desired 150 kW in a heavy duty BEV application. The 425 cc single cylinder two-stroke engine is an existing engine as one half of a 850 cc snowmobile engine. This simulation study includes upscaling of the swept volume, impact on engine speed and gas exchange properties. In the same way as for the 125cc engine [26], the exhaust gases reaches the turbine through a tuned exhaust pipe and an afterburner or oxidation catalyst.
Technical Paper

Development of a PN Surrogate Model Based on Mixture Quality in a GDI Engine

2021-09-05
2021-24-0013
A novel surrogate model is presented, which predicts the engine-out Particle Number (PN) emissions of a light-duty, spray-guided, turbo-charged, GDI engine. The model is developed through extensive CFD analysis, carried out using the Siemens Simcenter STAR-CD, and considers a range of part-load operating conditions and single-variable sweeps where control parameters such as start of injection and injection pressure are varied in isolation. The work is attached to the Ford-led APC6 DYNAMO project, which aims to improve efficiency and reduce harmful emissions from the next generation of gasoline engines. The CFD work focused on the air exchange, fuel spray and mixture preparation stages of the engine cycle. A combined Rosin-Rammler and Reitz-Diwakar model, calibrated over a wide range of injection pressure, is used to model fuel atomization and secondary droplets break-up.
Technical Paper

Combined CFD - Experimental Analysis of the In-Cylinder Combustion Phenomena in a Dual Fuel Optical Compression Ignition Engine

2021-09-05
2021-24-0012
Methane supply in diesel engines operating in dual fuel mode has demonstrated to be effective for the reduction of particulate matter and nitric oxides emissions from this type of engine. In particular, methane is injected into the intake manifold to form a premixed charge with air, while a reduced amount of diesel oil is still directly injected to ignite the mixture inside the cylinder. As a matter of fact, the liquid fuel burns following the usual diffusive combustion, so activating the gaseous fuel oxidation in a premixed flame. Clearly, the whole combustion process appears to be more complex to be described in a CFD simulation, mainly because it is not always possible to select in the 3-dimensional codes a different combustion model for each fuel and, also, because other issues arise from the interaction of the two fuels.
Technical Paper

Potentials of the Oversizing and H2-Supported Lean Combustion of a VVA SI Gasoline Engine Towards Efficiency Improvement

2021-09-05
2021-24-0007
In recent years, internal combustion engine (ICE) downsizing coupled with turbocharging was considered the most effective path to improve engine efficiency at low load, without penalizing rated power/torque performance at full load. On the other side, issues related to knocking combustion and excessive exhaust gas temperatures obliged adopting countermeasures that highly affect the efficiency, such as fuel enrichment and delayed combustion. Powertrain electrification allows operating the ICE mostly at medium/high loads, shifting design needs and constraints towards targeting high efficiency under those operating conditions. Conversely, engine efficiency at low loads becomes a less important issue. In this track, the aim of this work is the investigation of the potential of the oversizing of a small Variable Valve ActuationSpark Ignition gasoline engine towards efficiency increase and tailpipe emission reduction.
Technical Paper

Experimental and Numerical Analyses of Direct and Port Water Injection in a Turbocharged Spark-Ignition Engine

2021-09-05
2021-24-0035
Water injection represents a promising tool to improve performance of spark-ignition engines. It allows reducing in-cylinder temperature, preventing knock risks. Optimizing the spark advance, water injection allows obtaining an increase of both efficiency and power output, particularly at medium and high loads. Water can be injected into the intake port or directly into the combustion chamber. In this paper, the authors investigated the effects of both direct and port water injection in a downsized PFI spark-ignition engine at high load operation. Different water-to-fuel ratios have been analyzed for both configurations. For the experimental analysis, low-pressure water injectors have been installed in the intake ports of the engine under study, upstream of the fuel injectors. Experimental tests have been carried out at various operating points. Furthermore, engine operation with port water injection has been simulated by means of the AVL Fire 3-D code.
Technical Paper

Machine Learning Application to Predict Turbocharger Performance under Steady-State and Transient Conditions

2021-09-05
2021-24-0029
Performance predictions of advanced turbocharged engines are becoming difficult because conventional engine models are built using performance map data of turbochargers with a proportional integral derivative (PID) controller. Improving prediction capabilities under transient test cycles or real driving conditions is a challenging task. This study applies a machine learning technique to predict turbocharger performances with high accuracy under steady-state and transient conditions. The manipulated signals of engine speed and torque created based on Compressed High-Intensity Radiated Pulse (Chirp signal) and Amplitude-modulated Pseudo-Random Binary Signal (APRBS) are used as inputs to the engine testbed. Data from the engine experiments are used as training data for the AI-based turbocharger model. High prediction accuracy of the AI turbocharger model is achieved with the co-efficient of determination in the model, and cross-validation results are higher than 0.8.
Technical Paper

Comparison of Velocity Field in a Single-Cylinder Transparent Internal Combustion Engine under Cold Flow Conditions Using Particle Image Velocimetry and Computational Fluid Dynamics

2021-09-05
2021-24-0021
Internal combustion engine will remain the major propulsion system for land transportation, for at least the next decade, as the transition to full electrification will not be imminent. Thus, it is important to improve the combustion efficiency and emissions. To achieve this, it is important to understand and control the in - cylinder flow evolution, and primarily the Tumble development as this is strongly connected with the mixing process. Flow field measurements were obtained by using Time Resolved Particle Image Velocimetry technique in a 475cc optical single - cylinder Gasoline Direct Injection (GDI) spark ignition engine. The results include 50 consecutive cycles phase averaged velocity fields at 2000 RPM with wide open throttle.
Technical Paper

Deployment of Energy Saving Technologies on 2 Cylinder Common Rail Diesel Engine to Improve the Engine Mechanical Efficiency Moving from BSIV to BSVI

2021-09-22
2021-26-0046
Today the whole automotive world is progressively transforming towards the adoption of new alternate, advanced and innovative technologies evolving in ICE and Vehicle technology to meet the stringent emission regulations and future CO2 goals while protecting the environment. May it be Engine downsizing, Down speeding, Cylinder deactivation, VCR, VVT, Dynamic Skip Fire (DSF), Alternate fuels, Alternate materials, Steel pistons, Advanced thermal barrier/coating technology, Electrification or Various degrees of hybridization. The key to achieve better FE or reduction in CO2 emissions is realized by saving every pie of energy spent or reducing the parasitic losses and improving overall engine efficiencies wherever possible. In this paper, an experimental study on the deployment of various energy saving technologies, concepts are exploited on small 2 cylinder common rail BSVI engine for friction reduction and efficiency improvements while moving forward from BSIV to BSVI legislation phase.
Technical Paper

Efficient Overrunning Alternator Pulley (OAP) Design and Development for Robust FEAD System, Reduction of Fuel Consumption and CO2 for Model Gasoline Engine

2021-09-22
2021-26-0069
Complex FEAD system in modern powertrain is reality today due to demanding regulation, hybrid powertrain and increasing customer expectation. Gasoline engines are going to be preferred over diesel engines specially for passenger car application. These downsized engines lead to increase engine excitation and so to higher dynamics. Use of overrunning alternator pulley (OAP) is globally accepted as cost effective and technically proven product for FEAD system to make it robust by optimizing the system performance such as belt tension, hub load, slippage and vibrations to improve fuel consumption and to reduce engine emissions. OAP is a mechanical device with one-way clutch unit which eliminates the torsional vibrations coming from engine crankshaft and ensures only accelerating proportions of crankshaft forces are transferred to alternator which means reduction in force level of belt drive system.
Technical Paper

In-Cylinder Charge Motion Development for Gasoline Engine

2021-09-22
2021-26-0062
In the recent years world-wide automotive manufacturers are continuously working in the research of the suiTable technical solutions to meet upcoming stringent carbon dioxide (CO2) emission targets, defined by regulatory authorities across the world. Many technologies have been already developed, or are currently under study, to meet the legislated targets. To meet this objective, the generation of tumble at intake stroke and the conservation of turbulence intensity at the end of compression stroke inside the combustion chamber have a significant role in the contribution towards accelerating the burning rate, increasing the thermal efficiency and reducing the cyclic variability [1]. Tumble generation is mainly attained by intake port design, and conservation is achieved during the end of compression stroke 690 ~ 720 crank angles (CA) which is strictly affected by the piston bowl geometry and pentroof combustion chamber shape.
Technical Paper

Machine Learning based Operation Strategy for EV Vacuum Pump

2021-09-22
2021-26-0139
In an automotive braking system, Vacuum pump is used to generate vacuum in the vacuum servo or brake booster in order to enhance the safety and comfort to the driver. The vacuum pump operation in the braking system varies from conventional to electric vehicles. The vacuum pump is connected to the alternator shaft or CAM shaft in a conventional vehicle, operates continuously at engine speed and supplies continuous vacuum to the brake servo irrespective of vacuum requirement. To sustain continuous operation, these vacuum pumps are generally oil cooled. Whereas in electric vehicles, the use of a motor-driven vacuum pump is very much needed for vacuum generation as there is no engine present. Thus, with the assistance of an electronic control unit (ECU), the vacuum pump can be operated only when needed saving a significant amount of energy contributing to fuel economy and range improvement and emission reduction.
Technical Paper

Variation in Automotive Shock Absorber Damping Characteristics & Their Effects on Ride Comfort Attribute and Vehicle Yaw Response

2021-09-22
2021-26-0081
In a Passive suspension, a shock absorber generates damping force by pressurizing the oil flow between chambers. Typically, vehicle responds with suspension deflection, which significantly depends on damping forces and suspension velocity. Tuning dampers for various roads and steering input is an iterative balancing process. In any setting, damping force w.r.t velocity is tuned for optimum ride and handling performance. Practically, to achieve a balance between the two is a tedious task as the choices & arrangements of inner parts like piston, port, valve etc., which defines the forces set up [soft / hard] are almost infinite. The objective of this paper is to measure, objectify and evaluate the performance of two such optimum setting in various ride and handling events. A passenger car set up with an optimum soft & hard suspension damping force is studied for various ride and handling sub-attributes and their conflicts are examined in detail from a performance point of view:
Technical Paper

Investigation and Experimental Based Solution to Address High Particulate Matter Contributed from Open Crank Case Ventilation System in Automotive Diesel Engines to Meet Stringent Emission Norms BS6

2021-09-22
2021-26-0188
As part of transformation from BS4 to BS6 automobile emission standard in India, engine manufactures are focusing on continuous development of emission control technologies and suitable strategies. Exhaust tail pipe emission and Crankcase emission are added together to meet the regulation acceptable limit. The crankcase emissions contribute substantially to the total Particulate Matter (PM) emitted from an engine. Hence there is a need of design and development of suitable Crankcase ventilation system. This paper presents investigation of high PM contributed from Open Crankcase ventilation (OCV) system in Diesel engine and experiment based solutions.
Technical Paper

The Effect of Butanol-Gasoline Blends on Harmful Engine Deposits

2020-09-15
2020-01-2093
It is well known that alcohol based fuels may have been regarded as one of the alternative fuels because they have several physical and combustion properties similar to gasoline. Ethanol and butanol are alcohols considered as the most promising biocomponents for currently used conventional fuels. However, taking into account the numerous advantages of butanol over ethanol, and its properties, closer to those of gasoline, it is believed that it has greater application potential in the future environmentally-friendly fuels. For these reasons, butanol is under consideration to replace ethanol as an alternative fuel to gasoline especially as a gasoline blending bio-component. Therefore, this paper is focusing on the assessment of the influence of butanol addition to gasoline on harmful deposit formation in a various generation of spark ignition engine. Currently, only few research papers had discussed in very general this very important problem.
Technical Paper

Discretization and Heat Transfer Calculation of Engine Water Jackets in 1D-Simulation

2020-04-14
2020-01-1349
The industry is working intensively on the precision of thermal management. By using complex thermal management strategies, it is possible to make engine heat distribution more accurate and dynamic, thereby increasing efficiency. Significant efforts are made to improve the cooling efficiency of the engine water jacket by using 3D CFD. As well, 1D simulation plays a significant role in the design and analysis of the cooling system, especially for considering transient behaviour of the engine. In this work, a practice-oriented universal method for creating a 1D water jacket model is presented. The focus is on the discretization strategy of 3D geometry and the calculation of heat transfer using Nusselt correlations. The basis and reference are 3D CFD simulations of the water jacket. Guidelines for the water jacket discretization are proposed. The heat transfer calculation in the 1D-templates is based on Nusselt-correlations (Nu = Nu(Re, Pr)), which are derived from 3D CFD simulations.
Technical Paper

Mathematical Modeling of a Hydrodynamic Lubrication of a Piston Skirt Considering the Deformations and Dynamics of the Piston Displacement

2021-09-21
2021-01-1141
One of the first tasks while designing pistons is to ensure the reliable engine operation with minimal friction losses. This is possible by ensuring the liquid friction in the piston-cylinder junction during the entire operating cycle. Therefore, it is important to assess the nature of friction in the piston-cylinder conjunction. This task can be broken down into a number of interrelated subtasks: determining the characteristics of the piston lateral movement, determining the piston deformations under thermal and mechanical loads, and calculating the hydrodynamic forces acting from the side of the oil layer in the conjunction. The use of software packages that solve these problems separately and their inclusion in the iterative process will lead to huge expenditures of computing time and is difficult to implement in carrying out design optimization problems.
Technical Paper

Characterization and Comparison of Steady-Flow Techniques Used for Engine Airflow Development

2021-09-21
2021-01-1151
This paper compares bulk impulse-torque and 2D planar PIV steady flow-field measurements created by an engine cylinder head and intake system model using a steady-flow bench and evaluates operational aspects of the steady-flow test system. The model included a full-sized intake manifold and cylinder head section from a Chrysler 2.4L PFI four-valve per cylinder engine mounted to an optical cylinder. Two test system operational aspects were evaluated: (1) upstream versus downstream engine location relative to the flowbench (operational modes corresponding to flow bench pulling or pushing through the system), (2) PIV seeding particulate choice. Several dry and oil fog particulates were assessed however, of the options tested, only laboratory grade glass and consumer grade talc allowed long enough operation for practical data acquisition. Tests were performed over lift-over-diameter (L/D) ratios spanning from 0.1 to 0.3.
Technical Paper

Investigations into the Effects of Spark Plug Location on Knock Initiation by using Multiple Pressure Transducers

2021-09-21
2021-01-1159
Despite a long history of development, modern spark-ignition (SI) engines are still restricted in obtaining higher thermal efficiency and better performance by knock. Knocking combustion is an abnormal combustion phenomenon caused by the autoignition of unburned air-fuel mixture ahead of the propagating flame front. This work describes investigations into the significance of spark plug location (with respect to inlet and exhaust valve position) on the knock formation mechanism. To facilitate the investigation, four spark plugs were installed in a specialized liner at four equispaced distinct locations to propagate flames from those locations, which provoked a distinct flame propagation from each and thus individual autoignition profiles. Six pressure transducers were arranged to precisely record the pressure oscillations, knock intensities, and combustion characteristics.
Technical Paper

Homogeneous Charge with Direct Multi-Pulse Injection - A Promising High Efficiency and Clean Combustion Strategy for Diesel Engines

2021-09-21
2021-01-1156
Extensive experimental investigations done over a decade in different engine types demonstrated the capability of achieving high efficiency along with low levels of oxides of nitrogen (NOx) and soot emissions with low temperature combustion (LTC) modes. However, the commercial application of LTC strategies requires several challenges to be addressed, including precise ignition timing control, reducing higher unburned hydrocarbon (UHC) and carbon monoxide (CO) emissions. The lower exhaust gas temperatures with LTC operation pose severe challenges for after-treatment control systems. Among the available LTC strategies, Reactivity Controlled Compression Ignition (RCCI) has emerged as the most promising strategy due to better ignition timing control with higher thermal efficiency. Nevertheless, the complexity of engine system hardware due to the dual fuel injection system and associated controls, high HC and CO emissions are the major limiting factors in RCCI.
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