Data from a 3.43 kW piston engine-generator is integrated with rotorcraft sizing analysis to assess its impact. First, the measured SFC map of the powerplant is modeled. Second, the sizing is validated with XV-15 flight test aircraft and NASA conceptual reference quadrotor. The power and platform models are then integrated to size a hypothetical quadrotor bi-plane unmanned air vehicle of 5 lb payload. Several cases for how the engine can be operated to meet the vehicle torque and speed are detailed. The key conculsion is that a detailed SFC model is as important as the aircraft model. Without it, errors in tip speed reduction, gross weight, and range would be quite dramatic from 50-100%. A tip speed reduction to 65% hover in cruise was found to strike the best balance between rotor performance and engine performance of the hypothetical aircraft, resulting in a gross weight of 50 lb and range of 120 nm at 60 kts cruise speed.

Arace, Matt, Datta, Anubhav

EFFECT OF PISTON SECONDARY MOTION ON LUBRICATING OIL CONSUMPTION, BLOW-BY AND FRICTION

2024-26-02591/16/2024

As per pieces of literature, 40 to 60 % of friction losses in an Internal combustion engine occur in piston-ring pack-liner assembly and, there is a significant supportive role of simulation in improving this assembly. Literature is also available which tells, how changes in pistons affect oil consumption. Thus, piston dynamics plays an important role in oil consumption. Furthermore, the Piston Movement Module simulation results also serve as a very important input for postprocessing to calculate piston ring dynamics. This research work is conducted to understand the effect of piston secondary motion, on oil consumption, blow-by, and friction. In this work, the results of ring dynamics and oil consumption simulation modules are studied with consideration and non-consideration of piston secondary motion results. The parameters like minimum oil film thickness, lubricating oil consumption, blow-by, friction, and friction power loss are investigated. Results indicate that oil throw-off and

Sanadhya, Kunjan, Nandgaonkar, M., Aghav, Yogesh

Cost Effective Pathways Toward Highly Efficient and Ultra-Clean CI Engines, Part I: Combustion System Optimization

2024-26-00371/16/2024

Following global trends of increasingly stringent greenhouse gas (GHG) and criteria pollutant regulations, India will likely introduce within the next decade equivalent Bharat Stage (BS) regulations for Diesel engines requiring simultaneous reduction in CO2 emissions and up to 90% reduction in NOx emission from current BS-VI levels. Consequently, automakers are likely to face tremendous challenges in meeting such emission reduction requirements while maintaining performance and vehicle total cost of ownership (TCO), especially in the Indian market which has experienced significant tightening of emission regulation during the past decade. Therefore, it is conceivable that cost effective approaches for improving existing diesel engines platforms for future regulations would be of high strategic importance for automakers. In this first of a two-part article, cost effective means of improving the combustion process in a Diesel engine to reduce engine-out emissions, specifically of NOx and

Shah, Ashish, Kumar, Praveen, Sari, Rafael, Cleary, David, Gothekar, Sanjeev, Thipse, Sukrut S

OIL AEROSOL EMISSION OPTIMISAITON IN HIGH POWER DIESEL ENGINE USING DEFLECTORS IN TURBO CHARGER OIL DRAIN CIRCUIT

2024-26-00471/16/2024

Closed crankcase ventilation prevent harmful gases from entering atmosphere thereby reducing hydrocarbon emissions. Ventilation system carries blowby gases leaking through combustion process along with oil mist to Engine intake system. Major sources of blowby often occurs from leak in combustion chamber through piston rings, leaks from turbo shafts & valve guides. Oil mist carried away by blowby gases gets separated using filtration media. Fleece type separation media has high separation efficiency for particles above 10 microns. Efficiency drops if mist particle is below 10-micron size. Low size aerosol mist generally forms due to flash boiling on piston under crown area and on shafts of turbo charger due to high speeds combined with elevated oil temperatures. High power density diesel engine is taken for our study. It produces low particle size oil mist which contributes to aerosol emission of 3 gm/hr when operated at rated speed. Particle size measurement done using light refraction

M, Velshankar, Dharan R, Bharani, DHADSE, ASHISH, Permude, Ashok, Loganathan, Sekar

Experimental Study of Piston temperature profile with respect to varying engine parameters – Using Telemetry Method

2024-26-03411/16/2024

As emissions standards become more stringent, OEMs are pushing engines to run on leaner fuel mixtures, which puts increased thermal stress on components, particularly pistons, causing them to operate at higher temperatures. This requires more robust design and rigorous testing of components. Telemetry methods offer accurate and real-time feedback, allowing designers to test components at various operating conditions, providing more flexibility than other traditional methods. Piston temperature measurement is a critical aspect of engine development because it directly affects engine performance and durability. Among the various techniques available for this purpose, telemetry methods have gained considerable attention in recent years. This method involves integrating temperature sensors and transmitter on the piston, which transmit temperature data wirelessly to a receiver outside the engine. In this paper, we evaluate the impact of coolant temperatures, valve timing, ignition timing

Pandey, Ram Krishan, KUMAR, ATUL, Jangra, Sumit

Research on the Secondary Motion of Engine Piston Considering the Transport of Lubricating Oil

03-17-03-0024

11/21/2023

Abstract At present, it is generally considered in the analysis of the secondary motion of engine piston that the piston skirt–cylinder liner friction pair is fully lubricated in an engine operating cycle. However, in practice, when the piston moves upward, the amount of lubricating oil at the inlet may not ensure that the friction pair is fully lubricated. In this article, the secondary motion of piston is studied when the transport of lubricating oil is considered to determine the lubrication condition of piston skirt–cylinder liner friction pair. The secondary motion of piston is solved based on the combined piston motion model, hydrodynamic lubrication model, asperity contact model, and lubricating oil flow model. The secondary motion equation of piston is solved by the Broyden method. The hydrodynamic lubrication equation is solved by the finite difference method. The asperity contact between piston skirt and cylinder liner is calculated by the Greenwood model. The flow of

Liu, Jihai, Sun, Jun

Measurement of Piston Friction with a Floating Liner Engine for Heavy-Duty Applications

2022-01-07233/29/2022

The further increase in the efficiency of heavy-duty engines is essential in order to reduce CO2 emissions in the transport industry. This is also valid for the future use of alternative fuels, which can be CO2-neutral, but can cause higher total costs of ownership due to higher prices and limited availability. In addition to thermodynamic optimization, the reduction of mechanical losses is of great importance. In particular, there is a high potential in the piston bore interface, since continuously increasing cylinder pressures have a strong influence on the frictional and lateral piston forces. To meet these future challenges of increasing heavy-duty engine efficiency, AVL has developed a floating liner engine for heavy-duty applications based on its tried and tested passenger car floating liner concept. This article describes the concept of the friction single-cylinder engine developed to measure both the frictional forces and the lateral forces that occur between the piston

Edtmayer, Josef, Plettenberg, Mirko, Raser, Bernhard, Schäffer, Julian, Magyar, András, Szebényi, András, Knitlhoffer, Ádám, Littera, Daniele

Particulates in GDI and their relation to wall-film and mixing quality

2022-01-05173/29/2022

Particulates from GDI engines are inevitable, but can be kept low by means of various approaches such as high injection pressures, optimization of the spray formation, injection timing etc. It is known that liquid wall film on the piston and mixing are key factors influencing directly or indirectly the formation of particulates. It is almost impossible to completely avoid that the fuel spray impinges on the piston regardless of fuel injection timing which means that non-evaporated fuel can remain on the piston until late in the compression stroke or even further leading to increases in PN caused by pool-fires or rich zones. For a given fuel pressure, the timing of the fuel injection, SOI, is the most influencing factor. In this paper particulates data in numbers and sizes from experiments in single cylinder research engine are presented and used together with data of wall film and mixing quality from CFD simulations for sweeps in SOI timing. How the SOI sweeps were carried out in the

Dahlander, Petter, Babayev, Rafig, Ravi Kumar, Subhash, Etikyala, Sreelekha, Koopmans, Lucien

Multi-Dimensional CFD Studies of Oil Drawdown in an I4 Engine

2022-01-04733/29/2022

A computational study based on unsteady Reynolds Averaged Navier Stokes that resolves the gas-liquid interface was performed to examine the unsteady multiphase flow in a 4 cylinder Inline (I-4) engine. In this study, the rotating motion of the crankshaft and reciprocating motion of the pistons were accounted for to accurately predict the oil distribution in various parts of the engine. Three rotational speeds of the crankshaft have been examined: 1000, 2800, and 4000 RPM. Of particular interest is to examine the mechanisms governing the process of oil drawdown from the engine head into the case. The oil distributions in other parts of the engine have also been investigated to understand the overall crankcase breathing process. Results obtained show the drawdown of oil from the head into the case to be strongly dependent on the venting strategy for the foul air going out of the engine through the PCV system. Results also show the dynamic holdup of oil in the steady operation to be

Pandey, Ashutosh, Schlautman, Jeff, Nichani, Varun

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

2022-01-09453/29/2022

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. With the introduction of Sobol sampling method, the genetic algorithm (GA) was improved, which is superior in searching for the global optimal solutions. Meanwhile, a novel method was proposed for describing and parameterizing the piston bowl geometry. Moreover, by coupling KIVA-3V code with the enhanced GA, a total of 13 parameters including the piston bowl geometric parameters and the injection parameters were optimized with the objective of meeting Euro 6 regulations while improving the fuel efficiency. The optimal piston bowl shape coupled with the corresponding injection strategy was summarized and integrated at the various loads. The results show that the piston bowl geometry optimization can further improve the thermal efficiency over the test load range while the nitrogen oxides (NOx) and

Xu, Guangfu, Garcia, Antonio, Jia, Ming, Monsalve-Serrano, Javier

Design Challenges & Solution in Modifying Compact 4-Stroke Diesel Engine while Adapting D-Cycle Technology

2022-01-07253/29/2022

This paper reviews application of 2-Stroke D-Cycle (i.e. Differential Stroke) technology to compact tractor 4-Stroke 2.7L 4-Cylinder CRS (Common Rail System) Naturally aspirated (NA) Diesel engine for improving efficiency & power. The study considers design challenges that are presented for accommodating D-cycle technology in engine. The paper also covers resolving those challenges with established technical solutions. Study focuses on modifying conventional compact 4-stroke diesel engine with the intention of keeping design changes minimal for incorporating differential stroke technology. Designing of vertically splitting lightweight piston crown which can smoothly engaged and separated from main piston body without any impact, stem rod which connects piston crown with rocker arm, hollow connecting rod and rocker arm which is actuated by additional camshaft in addition to present camshaft. Lubrication of additional camshaft is done by extending existing oil galleries. Gear train

Telshinge, Pravin, Paulraj, Lemuel

The Rotating Liner Engine under Medium Loads and Speeds. Fuel economy benefit exceeds 10%

2022-01-05073/29/2022

The Rotating Liner Engine (RLE) is a design concept where the cylinder liner of a Heavy Duty Diesel engine rotates by about 2-4 m/s surface speed in order to eliminate the piston ring and skirt boundary friction near top and bottom dead center. Based on testing results from our single cylinder RLE prototype (a converted four cylinder Cummins ISB 3.9 diesel) compared to a similar baseline, under idle conditions, the friction reduction is approximately 50 kPa in FMEP (friction mean effective pressure), which translates to about 40% for a complete engine. In this new set of experiments, we are comparing the RLE performance under load of up to about 7 bar IMEP (indicated mean effective pressure). It has been proven that the elimination of metallic contact between the compression rings and cylinder persists under up to 75 bar peak cylinder pressure and 1.5-2 m/s liner surface speed (283-383 rpm) for the 850-1150 rpm crankshaft speed. Additionally, the RLE FMEP is substantially reduced under

Dardalis, Dimitrios, ALHAJ ASAD, Osama, Basu, Amiyo, Hall, Matthew, Matthews, Ron

Analysis of Gasoline Engine Piston for Carbon Fiber Material

2022-01-04063/29/2022

In the present study, an automotive gasoline engine piston was designed and its various structural and thermal properties were analyzed for three different materials, namely, Gray Cast Iron, Aluminum Alloy, and Epoxy Carbon Woven (230 GPa) Prepreg. The design was done on SolidWorks 2019 and the analysis was carried out on ANSYS v18.1. The lightweight of the Epoxy Carbon Woven (230 GPa) Prepreg piston as compared to the other two pistons suggests that the inertial forces are reduced for the carbon fiber material. It is also observed that the structural strength of the Epoxy Carbon Woven (230 GPa) Prepreg material piston is more than that of Gray Cast Iron, and Aluminum Alloy piston. The temperature variation for the Epoxy Carbon Woven (230 GPa) Prepreg piston is less than that of the Gray Cast Iron and Aluminum Alloy piston, thus giving it a better thermal conductivity. The heat flux for the Gray Cast Iron and Aluminum Alloy pistons is greater than that of Epoxy Carbon Woven (230 GPa

Jain, Devanshu, Paul, Shourya, Brella, Rohan, Kumar, Naveen

Wear and Friction of PTFE and PEEK Coated Cast Iron Piston Ring

2022-01-03803/29/2022

In engine 30% of the total energy is lost due to the friction between piston ring and cylinder liner due to their constant rubbing motion. A piston that reciprocates at high speeds has piston rings that constantly scrape against the wall leading to high frictional losses within the engine. The engine has to work against this resistance to provide the required power, and hence it will consume more fuel. For this reason, material used for these components is more crucial. Reduction of surface friction between moving parts in order to increase overall efficiency can be achieved by suitable coating. The most commonly used piston rings are coated with chromium layers that are electroplated which is being replaced by chrome plating. Low coefficient of friction (COF) and high wear resistance can be achieved by self-lubricating coating of PTFE and PEEK polymer-based composite coatings. Experimental results showed that the PEEK and PTFE coating performed better in terms of friction and wear

Rajendran, R.

Gland Design, O-Ring and Other Seals

AS4716D (Current)

11/9/2021

This SAE Aerospace Standard (AS) provides standardized gland (groove) design criteria and dimensions for O-ring seal glands for static and dynamic applications, and other seals.

A-6C2 Seals Committee