scholarly journals The Practical Range of Expansion and Compression Ratios for an Atkinson Cycle Engine

2021 ◽  
Vol 9 (5) ◽  
pp. 1005-1007
Author(s):  
P Srinivas Kalyan
Keyword(s):  
Atkinson Cycle

scholarly journals A Theoretical Study on the Thermodynamic Cycle of Concept Engine with Miller Cycle

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1051
Author(s):  
Jungmo Oh ◽  
Kichol Noh ◽  
Changhee Lee
Keyword(s):  
Compression Ratio ◽  
Thermal Efficiency ◽  
Engine Performance ◽  
Thermodynamic Cycle ◽  
Expansion Ratio ◽  
Boost Pressure ◽  
Miller Cycle ◽  
Compression Pressure ◽  
Air Mass ◽  
Atkinson Cycle

The Atkinson cycle, where expansion ratio is higher than the compression ratio, is one of the methods used to improve thermal efficiency of engines. Miller improved the Atkinson cycle by controlling the intake- or exhaust-valve closing timing, a technique which is called the Miller cycle. The Otto–Miller cycle can improve thermal efficiency and reduce NOx emission by reducing compression work; however, it must compensate for the compression pressure and maintain the intake air mass through an effective compression ratio or turbocharge. Hence, we performed thermodynamic cycle analysis with changes in the intake-valve closing timing for the Otto–Miller cycle and evaluated the engine performance and Miller timing through the resulting problems and solutions. When only the compression ratio was compensated, the theoretical thermal efficiency of the Otto–Miller cycle improved by approximately 18.8% compared to that of the Otto cycle. In terms of thermal efficiency, it is more advantageous to compensate only the compression ratio; however, when considering the output of the engine, it is advantageous to also compensate the boost pressure to maintain the intake air mass flow rate.

Simulation of Extended Expansion Lean Burn Spark Ignition Engine

2004 ◽  
Author(s):  
A. Manivannan ◽  
R. Ramprabhu ◽  
P. Tamilporai ◽  
S. Chandrasekaran
Keyword(s):  
Heat Transfer ◽  
Compression Ratio ◽  
Thermal Efficiency ◽  
Numerical Study ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Valve Closure ◽  
Intake Valve ◽  
Lean Burn ◽  
Atkinson Cycle

This paper deals with Numerical Study of 4-stoke, Single cylinder, Spark Ignition, Extended Expansion Lean Burn Engine. Engine processes are simulated using thermodynamic and global modeling techniques. In the simulation study following process are considered compression, combustion, and expansion. Sub-models are used to include effect due to gas exchange process, heat transfer and friction. Wiebe heat release formula was used to predict the cylinder pressure, which was used to find out the indicated work done. The heat transfer from the cylinder, friction and pumping losses also were taken into account to predict the brake mean effective pressure, brake thermal efficiency and brake specific fuel consumption. Extended Expansion Engine operates on Otto-Atkinson cycle. Late Intake Valve Closure (LIVC) technique is used to control the load. The Atkinson cycle has lager expansion ratio than compression ratio. This is achieved by increasing the geometric compression ratio and employing LIVC. Simulation result shows that there is an increase in thermal efficiency up to a certain limit of intake valve closure timing. Optimum performance is attained at 90 deg intake valve closure (IVC) timing further delaying the intake valve closure reduces the engine performance.

scholarly journals Benchmarking a 2018 Toyota Camry 2.5-Liter Atkinson Cycle Engine with Cooled-EGR

2019 ◽  
Author(s):  
John Kargul ◽  
Mark Stuhldreher ◽  
Daniel Barba ◽  
Charles Schenk ◽  
Stanislav Bohac ◽  
...  
Keyword(s):  
Atkinson Cycle

scholarly journals MATHEMATICAL MODEL OF PETROL ENGINE WORKING ON ATKINSON CYCLE

2019 ◽  
Vol 0 (1) ◽  
pp. 8-14
Author(s):  
Т. М. Колеснікова ◽  
В. Г. Заренбін ◽  
О. П. Сакно ◽  
В. П. Олло
Keyword(s):  
Mathematical Model ◽  
Petrol Engine ◽  
Atkinson Cycle

scholarly journals Characterization of Performance of Short Stroke Engines with Valve Timing for Blended Bioethanol Internal Combustion

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 759 ◽  
Author(s):  
Kun-Ho Chen ◽  
Yei-Chin Chao
Keyword(s):  
Co2 Emissions ◽  
Ignition Time ◽  
Engine Performance ◽  
Valve Timing ◽  
Atkinson Cycle ◽  
Blended Fuel ◽  
Exhaust Valves ◽  
Blended Fuels ◽  
Stroke Engine

The present study provides a feasible strategy for minimizing automotive CO2 emissions by coupling the principle of the Atkinson cycle with the use of bioethanol fuel. Motor cycles and scooters have a stroke to bore ratio of less than unity, which allows higher speeds. The expansion to compression ratio (ECR) of these engines can be altered by tuning the opening time of the intake and exhaust valves. The effect of ECR on fuel consumption and the feasibility of ethanol fuels are still not clear, especially for short stroke engines. Hence, in this study, the valve timing of a short stroke engine was tuned in order to explore potential bioethanol applications. The effect of valve timing on engine performance was theoretically and experimentally investigated. In addition, the application of ethanol/gasoline blended fuels, E3, E20, E50, and E85, were examined. The results show that consumption, as well as engine performance of short stroke motorcycle engines, can be improved by correctly setting the valve controls. In addition, ethanol/gasoline blended fuel can be used up to a composition of 20% without engine modification. The ignition time needs to be adjusted in fuel with higher compositions of blended ethanol. The fuel economy of a short stroke engine cannot be sharply improved using an Atkinson cycle, but CO2 emissions can be reduced using ethanol/gasoline blended fuel. The present study demonstrates the effect of ECR on the performance of short stroke engines, and explores the feasibility of applying ethanol/gasoline blended fuel to it.

Investigations of Atkinson Cycle Converted from Conventional Otto Cycle Gasoline Engine

2016 ◽  
Author(s):  
Renhua Feng ◽  
Yangtao Li ◽  
Jing Yang ◽  
Jianqin FU ◽  
Daming Zhang ◽  
...  
Keyword(s):  
Gasoline Engine ◽  
Otto Cycle ◽  
Atkinson Cycle
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