Performance analysis of a novel eco‐friendly internal combustion engine cycle

2019 ◽  
Vol 43 (11) ◽  
pp. 5897-5911
Author(s):  
Guven Gonca ◽  
Bahri Sahin
Keyword(s):  
Performance Analysis ◽  
Internal Combustion Engine ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Engine Cycle

Design of Turbo-Compression System for HALE UAV Propulsion System

2018 ◽  
Author(s):  
Young Seok Kang ◽  
Dong Ho Rhee ◽  
Byeung Jun Lim ◽  
Sangook Jun ◽  
Tae Choon Park ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Performance Analysis ◽  
Internal Combustion Engine ◽  
High Altitude ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Propulsion System ◽  
Flight Altitude ◽  
Compression System ◽  
Main Components

A turbo-compression system design and its performance analysis procedure for a high altitude long endurance UAV (HALE UAV), of which cruising altitude is within the stratosphere, is presented. To fly at a relatively low speed for a long time and to make engine performance less sensitive to flight altitude, a hydrogen fueled internal combustion engine was chosen for a propulsion system. To utilize an internal combustion engine as a propulsion system at a high altitude, a proper inlet pressure boost system such as a series of turbochargers is required. Hydrogen is highly reactive gas and sometimes backfiring or preignition may occur due to its low ignition energy at stoichiometric ratio. Therefore, fuel to air ratio should be reduced as low as 0.6 to avoid such phenomena. Then rarefied ambient intake air pressure should be boosted up to 1.7 bar to produce required power from the lean burn engine. To gain high pressure ratio from the turbo compression system, at least three stage serial turbocharger with proper intercooler system at each compressor exhaust is required. To analyze multi-stage turbocharger performance at the cruising altitude, an explicit one-dimensional analysis method has been established mainly by matching required power between compressors and turbines. Each compressor performances were corrected according to Reynolds number at a given flight altitude. Compressor efficiency and surge margin deteriorate as the operating altitude increases. Then compressor efficiencies were reflected as functions of flight altitude and corresponding Reynolds number. Once operating points of each turbocharger was determined, then adequate turbochargers were searched for from commercially available models based on performance analysis results. Also, adequate water to air intercoolers were chosen for the turbo-compression system to secure flexibility of placing main components inside the engine bay as well as to obtain high heat exchange efficiency of the heat exchangers. Based on the designed turbo-compression system, technical demonstration test of the turbo-compression system inside altitude environment test chamber in Korea Aerospace Research Institute is planned. Altitude condition in stratosphere is simulated mainly with two stage centrifugal compressor and additional fan will be used to fine control the flight altitude. The turbo compression system will be controlled with a single waste gate located just downstream of the engine to secure simple controllability of the turbo compression system. The test results will validate main components as well as system layout design methods and give more reliable control schedule of the turbo compressions system according to the flight altitude.

Dynamic analysis of piston secondary motion in an internal combustion engine under non-lubricated and fully flooded lubricated conditions

2011 ◽  
Vol 225 (11) ◽  
pp. 2575-2585 ◽  
Author(s):  
P D McFadden ◽  
S R Turnbull
Keyword(s):  
Internal Combustion Engine ◽  
Dynamic Analysis ◽  
Dynamic Model ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Gas Pressure ◽  
Single Cylinder Engine ◽  
Secondary Motion ◽  
Steady Rotation ◽  
Engine Cycle

A dynamic model is presented for the internal combustion engine in which the primary motion of the pistons is determined by the gas pressure in the cylinders rather than by an assumed steady rotation of the crank, and the secondary motion of the pistons is determined by the interaction of the pistons with the cylinder walls under non-lubricated and fully flooded lubricated conditions. Results are presented for the simulation of a single-cylinder engine and show clearly the variations in the secondary translation and rotation of the piston throughout the engine cycle for the non-lubricated condition, and the significant damping of such secondary motions in the fully flooded lubricated condition.

Characterization of Crankcase Pressure Variation during the Engine Cycle of an Internal Combustion Engine

2017 ◽  
Author(s):  
Katherine Randall ◽  
Cody Bradford ◽  
Jeremy Ross ◽  
Jeremy Church ◽  
Nolan Dickey ◽  
...  
Keyword(s):  
Internal Combustion Engine ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Pressure Variation ◽  
Engine Cycle
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