The Otto-Atkinson Cycle Engine-Fuel Economy and Emissions Results and Hardware Design

Boggs, David L.; Hilbert, H. Sean; Schechter, Michael M.

doi:10.4271/950089

Cited by 35 publications

(7 citation statements)

References 2 publications

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“…In the ideal Atkinson cycle, the heat input process takes place under the constant volume condition as in the Otto cycle, and the heat output process takes place under the constant pressure condition. The reason why Atkinson cycle engines are preferred in hybrid-electric vehicles is their low power density (maximum power per unit engine volume) and high thermal efficiency compared to the Otto cycle engine (Boggs et al, 1995). In other words, Atkinson cycle engines can operate in more economic conditions than Otto cycle engines.…”

Section: Introductionmentioning

confidence: 99%

Specific Net Work and Mean Effective Pressure Based Thermodynamic Analysis and Optimization of Ideal Atkinson Cycle

Arabacı

Kılıç

2022

Konya Journal of Engineering Sciences

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In this study, the criteria for maximum values of specific net work and mean effective pressure in the air standard Atkinson cycle, which is the ideal thermodynamic cycle of internal combustion engines used in hybrid electric vehicles, were examined. For this, it was assumed that the cycle operates in a certain temperature range. Thus, while the maximum temperature of the cycle is constant, the compression ratio was optimized for maximum specific net work and maximum mean effective pressure. A case study was conducted for this study. For the case study, assuming the geometric expansion ratio of 12, the maximum temperature value of the cycle was determined as 1961.923 K. Based on this maximum temperature value, the maximum values of the specific net work and the ambient effective pressure were determined as 580.139 kJ/kg and 373.857 kPa, respectively. In addition, the geometric compression ratios for the maximum values of the specific net work and the ambient effective pressure were determined as 15.462 and 31.063, respectively. Looking at the geometric compression ratio values of today's engines, it was seen that these values were closer to the compression ratio at which the maximum specific net work was achieved. It was observed that the thermal efficiency increased when the compression ratio was optimized for the conditions where the maximum average effective pressure was achieved. The results obtained from this study are particularly attractive to engine designers.

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Section: Introductionmentioning

confidence: 99%

Specific Net Work and Mean Effective Pressure Based Thermodynamic Analysis and Optimization of Ideal Atkinson Cycle

Arabacı

Kılıç

2022

Konya Journal of Engineering Sciences

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“…In addition, the Miller cycle reduces NOx emissions by reducing the compression and combustion peak temperatures. The Miller cycle is one of the best methods to satisfy IMO (International Maritime Organization) Tier III regulations and improve thermal efficiency [38][39][40][41][42]. Therefore, determining the intake-valve closing timing, called the Miller timing, is one of the most important processes in developing auxiliary gas engines for ships.…”

Section: Introductionmentioning

confidence: 99%

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

Noh

Lee

2021

Processes

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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.

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“…21 Atkinson cycle is conducive to energy saving of engines, so its implementation methods, applications and challenges are widely concerned. [22][23][24] Boggs et al 25 achieved a flexible Otto-Atkinson cycle switching on a fourcylinder petrol engine with working on Otto cycle at full load and working on Atkinson cycle at part load, ultimately resulting in the improvement of fuel economy and emissions. Benajes et al 26 greatly reduced the NO X emissions of the diesel engine after applying Atkinson cycle and EGR technology to the diesel engine.…”

Section: Introductionmentioning

confidence: 99%

Combustion and energy distribution of hydrogen-enriched compressed natural gas engines with low heat rejection based on Atkinson cycle

Yang

Han

et al. 2019

Advances in Mechanical Engineering

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In order to reduce the heat loss and improve the indicated thermal efficiency of hydrogen-enriched compressed natural gas engines, this article presents a combination of Atkinson cycle with high compression ratio and low heat rejection on the hydrogen-enriched compressed natural gas prototype engine with 55% hydrogen blend. The combustion characteristics and energy distribution of the prototype and modified engines were investigated by simulation, and the conclusions are as follows: the pressure and temperature of modified engines are higher than those of the prototype during the combustion process. Compared with the prototype, the modified engines present lower peak heat release rate, but faster combustion after ignition, and their CA50 are closer to top dead center. Although the high compression ratio engine with Atkinson cycle generates more heat loss, its indicated thermal efficiency still increases by 0.6% with the decrease in the exhaust energy. Furthermore, the high compression ratio engine with low heat rejection and Atkinson cycle combines the advantages of low heat loss and relatively longer expansion stroke, so its heat loss reduces obviously, and 61.6% of the saved energy from low heat rejection and Atkinson cycle can be converted into indicated work that indicates a 4.5% improvement in indicated thermal efficiency over the prototype, which makes it perform better in terms of power and fuel economy simultaneously.

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The Otto-Atkinson Cycle Engine-Fuel Economy and Emissions Results and Hardware Design

Cited by 35 publications

References 2 publications

Specific Net Work and Mean Effective Pressure Based Thermodynamic Analysis and Optimization of Ideal Atkinson Cycle

Specific Net Work and Mean Effective Pressure Based Thermodynamic Analysis and Optimization of Ideal Atkinson Cycle

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

Combustion and energy distribution of hydrogen-enriched compressed natural gas engines with low heat rejection based on Atkinson cycle

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