scholarly journals Liquid Cooled Turbocharged Propulsion System for HALE Application

1991 ◽  
Author(s):  
R. E. Wilkinson ◽  
R. B. Benway
Keyword(s):  
High Altitude ◽  
New Technology ◽  
Spark Ignition ◽  
Propulsion System ◽  
Spark Ignition Engine ◽  
Reciprocating Engine ◽  
Power Turbine ◽  
Significant Performance ◽  
Technical Assessment ◽  
Long Endurance

An unmanned air vehicle (UAV) capable of sustained flight in the upper limits of the tropopause is a relatively new technology which has seen increasing interest during the past decade. Mission lengths for High Altitude Long Endurance (HALE) applications are typically measured in days rather than hours with operating altitudes ranging from 50,000 to 100,000 feet. An Otto cycle propulsion system offers significant performance advantages over other cycles. This paper provides a technical assessment of a liquid cooled turbocharged, reciprocating engine concept capable of meeting the requirements for a HALE vehicle. A properly designed spark ignition engine with a two or three stage series turbocharger system utilizing state-of-the-art aerodynamic design can meet the challenges presented at these altitudes. Several records for long endurance and high altitude flight have already been set with this type of propulsion system. A comparison with other candidate engines will also be made. The ability to operate with low brake specific fuel consumption (BSFC) across a broad operating range will be identified. With sufficiently high exhaust gas temperatures, the addition of a power turbine for turbocompounding can further reduce the BSFC and brake specific air consumption (BSAC). A version of the turbocharged spark ignition engine is capable of providing high thermal efficiency with the least BSAC and minimum turbomachinery weight.

scholarly journals Propulsion System Evaluation for an Unmanned High Altitude Long Endurance RPV

1991 ◽  
Author(s):  
Edward J. Kowalski ◽  
Norman C. Baullinger ◽  
Jennifer Kolden
Keyword(s):  
High Altitude ◽  
Propulsion System ◽  
Spark Ignition Engine ◽  
System Evaluation ◽  
Propulsion Systems ◽  
Atmospheric Sampling ◽  
Turboshaft Engine ◽  
Long Endurance ◽  
Rescue Drug ◽  
Selection Of

Unmanned High-Altitude Long-Endurance (HALE) aircraft have been studied for several years. Reconnaissance, surveillance, search and rescue, drug interdiction, atmospheric sampling, etc. are a few of the potential missions for HALE aircraft. One of the pacing technology items for an aircraft of this type is the propulsion system. This paper will discuss three candidate propulsion systems: a turbocompounded spark ignition engine, a recuperative turboshaft engine and a turbocharged turbocompounded diesel-turbine. HALE mission requirements dictate that certain parameters influence the selection of the propulsion system: propulsion system weight per horsepower, brake specific fuel consumption (lb/hr/shp), and reliability.

Performance of Combustion and Emissions Characteristics of Ethanol Dual Injection Spark Ignition Engine

2021 ◽  
Vol 18 (3) ◽  
pp. 9082-9093
Author(s):  
NIZAR F.O. AL-MUHSEN ◽  
Guang Hong ◽  
Firas Basim Ismail
Keyword(s):  
New Technology ◽  
Direct Injection ◽  
Engine Performance ◽  
Volume Ratio ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Nitric Oxides ◽  
Ethanol Fuel ◽  
Spark Timing ◽  
Dual Injection

Ethanol dual injection (DualEI) is a new technology to maximise the benefits of ethanol fuel to the spark-ignition engine. In this study, the combustion and emissions characteristics in a DualEI spark-ignition engine with a variation of the direct injection (DI) ratio and engine speed were experimentally investigated. The volume ratio of DI was varied from 0% (DI0%) to 100% (DI100%), and two engine speeds of 3500 and 4000 RPM were tested. The spark timing for maximum brake torque (MBT) was first determined, and then the results of the effect of DI ratio on the engine performance at the MBT conditions were discussed and analysed. The results showed that the MBT timing for the DI and spark timings were 330 and 30 CAD bTDC, respectively. At the MBT timing, the indicated mean effective pressure slightly increased from 0.47 to 0.50 MPa when the DI ratio increased from DI0% to DI100%. However, the maximum combustion pressure significantly decreased by 8.32%, and volumetric efficiency increased by 4.04%. This was attributed to the reduced combustion temperature due to the cooling effect of ethanol fuel enhanced by the DI strategy. The indicated specific carbon monoxide and hydrocarbons significantly increased due to poor mixture quality caused by fuel impingement associated with the overcooling effect. However, the indicated specific nitric oxides significantly decreased due to the temperature reduction inside the combustion chamber. Results showed the potential of DualEI to increase the compression ratio and consequently increase the engine thermal efficiency without the risk of engine knock.

scholarly journals Bio-oil blended butanol as a fuel to the spark ignition internal combustion reciprocating engine

2017 ◽  
Vol 169 (2) ◽  
pp. 93-96
Author(s):  
Mariusz CHWIST ◽  
Stanisław SZWAJA ◽  
Karol GRAB-ROGALIŃSKI ◽  
Michał PYRC
Keyword(s):  
Organic Matter ◽  
Ambient Temperature ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Cylinder Pressure ◽  
Pyrolysis Process ◽  
Reciprocating Engine ◽  
Bio Oil

The article presents results on combustion of the bio-oil blended butanol in the spark ignition engine. Bio-oil is a mixture of hydro-carbons condensing to liquified phase while cooling it down to ambient temperature. In general, the liquid called bio-oil is a byproduct of the pyrolysis process of organic matter. Results from analysis presented in the manuscript include the following: in-cylinder pressure traces and toxic exhaust emissions. Finally, comparison of these results with results from combustion of n-butanol reference fuel were provided. Obtained results indicate satisfactory, eco-friendly possibility for utilization of bio-oil in the internal combustion engine

Performance test and simulation of a reciprocating engine for long endurance miniature unmanned aerial vehicles

2005 ◽  
Vol 219 (4) ◽  
pp. 573-581 ◽  
Author(s):  
Younggy Shin ◽  
Sung-Ho Chang ◽  
Sam-Ok Koo
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Fuel Economy ◽  
Performance Test ◽  
Spark Ignition Engine ◽  
Simulation Program ◽  
Successful Implementation ◽  
Reciprocating Engine ◽  
High Speeds ◽  
Aerial Vehicles ◽  
Long Endurance

Development of an engine with good fuel economy is very important for successful implementation of long endurance miniature UAVs (unmanned aerial vehicles). In the study, a four-stroke glow-plug engine was modified to a gasoline-fuelled spark ignition engine. Engine tests measuring performance and friction losses were conducted to tune a simulation program for performance prediction. It has been found that excessive friction losses are caused by insufficient lubrication at high speeds. The simulation program predicts that engine power and fuel economy become worse with high altitude, due to an increasing portion of friction losses. The simulation results suggest quantitative guidelines for further development of a practical engine.

scholarly journals Propulsion Requirements for High Altitude Long Endurance Flight

1991 ◽  
Author(s):  
Roger W. Gallington
Keyword(s):  
High Altitude ◽  
Fuel Consumption ◽  
Propulsion System ◽  
Specific Power ◽  
Power Requirement ◽  
Active Involvement ◽  
Performance Requirements ◽  
And Control ◽  
Cooling Air ◽  
Long Endurance

This paper presents a set of general propulsion system performance requirements for high altitude long endurance flight. This flight objective places dramatically different values on fuel consumption, air consumption, system weight, and required heat rejection than the better understood range-payload objective. Some differences in overall vehicle design that suggest unusual propulsion systems are: (1) Optimum wing loadings for endurance at altitude are lower than acceptable for adequate wind penetration during descent and control during landing; (2) Compressing and cooling air at high altitudes requires large apparatus making specific air consumption very important; and (3) The lower specific power requirement and large fuel fractions make fuel consumption relatively more important than system weight. Based on the realistic expectations of aircraft aerodynamic performance and structural efficiency, the paper derives the correct propulsion system tradeoffs and extends these tradeoffs to include electrically-powered aircraft. A propulsion system designer can use the material presented here to guide the design of a high altitude long endurance propulsion system without active involvement of an airplane design team. The resulting propulsion design will be near-optimum.

scholarly journals Evaluation of Potential Engine Concepts for a High Altitude Long Endurance Vehicle

1988 ◽  
Author(s):  
Edward J. Kowalski
Keyword(s):  
High Altitude ◽  
Propulsion System ◽  
Turbofan Engine ◽  
Counter Rotation ◽  
Long Endurance ◽  
Bypass Ratio

A potential need has been identified for a High Altitude Long Endurance (HALE) aircraft to augment current surveillance and engagement capability. HALE platforms offer mission flexibility and survivability which can complement ground based surveillance and engagement systems. Current mission requirements include a loiter altitude of 45,000 to 60,000 feet and a loiter time of 12 to 24 hours. The HALE aircraft will also be required to carry a sensor payload weight between 50,000 and 100,000 pounds. This paper will evaluate the potential of several propulsion system candidates. Engines to be examined include the “classical” turbofan engine with bypass ratios up to eight, the “ultra high bypass ratio” turbofan with bypass ratios up to 20, General Electric’s Unducted Fan (UDF) and the turboprop in a pusher and tractor configuration with single and counter rotation propfans.

EFFECT OF AIR-FUEL RATIO ON SYNGAS COMBUSTION IN AN OPTICALLY ACCESSIBLE SPARK IGNITION ENGINE

2017 ◽  
Author(s):  
santiago daniel martinez boggio ◽  
Pedro Lacava ◽  
Maycon Silva ◽  
SIMONA MEROLA ◽  
Adrian Irimescu ◽  
...  
Keyword(s):  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Fuel Ratio ◽  
Syngas Combustion
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