High Efficiency Hybrid Cycle Engine

Shkolnik, Nikolay; Shkolnik, Alexander

doi:10.1115/icef2005-1221

Cited by 7 publications

(5 citation statements)

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“…A high-efficiency hybrid thermodynamic cycle can be defined as the configuration integrating various thermodynamic cycles [34]. In this cycle, the air is squeezed into an isolated combustion chamber, enabling true isochoric combustion and lengthy combustion time.…”

Section: Hybrid Thermal Cyclementioning

confidence: 99%

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Improving Thermal Efficiency of Internal Combustion Engines: Recent Progress and Remaining Challenges

2022

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Improving thermal efficiency and reducing carbon emissions are the permanent themes for internal combustion (IC) engines. In the past decades, various advanced strategies have been proposed to achieve higher efficiency and cleaner combustion with the increasingly stringent fuel economy and emission regulations. This article reviews the recent progress in the improvement of thermal efficiency of IC engines and provides a comprehensive summary of the latest research on thermal efficiency from aspects of thermodynamic cycles, gas exchange systems, advanced combustion strategies, and thermal and energy management. Meanwhile, the remaining challenges in different modules are also discussed. It shows that with the development of advanced technologies, it is highly positive to achieve 55% and even over 60% in effective thermal efficiency for IC engines. However, different technologies such as hybrid thermal cycles, variable intake systems, extreme condition combustion (manifesting low temperature, high pressure, and lean burning), and effective thermal and energy management are suggested to be closely integrated into the whole powertrains with highly developed electrification and intelligence.

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Section: Hybrid Thermal Cyclementioning

confidence: 99%

“…The key implementation challenges of the hybrid thermal cycle involve larger mechanical losses, a larger percentage loss of heat transfer, and rousted thermal management for minimizing heat transfer [34].…”

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confidence: 99%

Improving Thermal Efficiency of Internal Combustion Engines: Recent Progress and Remaining Challenges

2022

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“…LiquidPiston proposed the X engine (XE), an RTE type [7], with quite different geometry from the WE: the WE has two lobes in the housing, whereas the XE has two lobes in the rotor and three lobes in the housing. Both engines were designed using the Gerotor pump (GP) shape function [8,9].…”

Section: Introductionmentioning

confidence: 99%

Optimal Design for New Rotary Engine with Geometric Shape Functions on Combustion Chamber and Ports

Kim,

Park,

Yang

et al. 2024

Energies

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This study presents an optimal design for a new rotary engine. Instantaneous shape functions were applied to the combustion chamber, and intake and exhaust ports were derived based on the rotor and housing design functions; then optimized design parameters were derived for a rotary engine. The three main parameters were shape distance, eccentric distance and rotor thickness. The design process for the optimized internal shape was subsequently defined considering target specifications for the rotary engine, and a prototype engine was designed and fabricated with a 336 cm3 intake volume. The compression pressure for the prototype engine was compared with the motoring test and calculated. These outcomes confirmed the new engine’s feasibility, and the derived geometric shape functions will be helpful to ensure optimal design for rotary engines using one- or three-dimensional computational fluid dynamics.

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“…This is done simply by changing the locations of intake and exhaust ports asymmetrically which allows for the extraction of more energy during the expansion stroke. Further, a power stroke of the X engine occurs 3 times per rotor revolution resulting in a high power density [12]. LiquidPiston has developed initial prototypes to demonstrate the principles of the engine, including the X1, 1370 cc (70HP) and the XMv3, 70cc (3HP).…”

Section: Introductionmentioning

confidence: 99%

“…Table 1 shows a quantitative comparison of the cycles. From the analysis, the ideal thermodynamic efficiency (η) of HEHC is 38 % higher than Diesel, and 35 % higher than Otto cycle [12]. The actual efficiency for each cycle will be lower than its ideal gas standard cycle.…”

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confidence: 97%

Development of a Small Rotary SI/CI Combustion Engine

Shkolnik¹,

Littera²,

Nickerson³

et al. 2014

SAE Technical Paper Series

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This paper describes the development of small rotary internal combustion engines developed to operate on the High Efficiency Hybrid Cycle (HEHC). The cycle, which combines high compression ratio (CR), constant-volume (isochoric) combustion, and overexpansion, has a theoretical efficiency of 75% using air-standard assumptions and first-law analysis. This innovative rotary engine architecture shows a potential indicated efficiency of 60% and brake efficiency of >50%. As this engine does not have poppet valves and the gas is fully expanded before the exhaust stroke starts, the engine has potential to be quiet. Similar to the Wankel rotary engine, the 'X' engine has only two primary moving partsa shaft and rotor, resulting in compact size and offering low-vibration operation. Unlike the Wankel, however, the X engine is uniquely configured to adopt the HEHC cycle and its associated efficiency and low-noise benefits. The result is an engine which is compact, lightweight, low-vibration, quiet, and fuel-efficient. Two prototype engines are discussed. The first engine is the larger X1 engine (70hp), which operates on the HEHC with compression-ignition (CI) of diesel fuel. A second engine, the XMv3, is a scaled down X engine (70cc / 3HP) which operates with spark-ignition (SI) of gasoline fuel. Scaling down the engine presented unique challenges, but many of the important features of the X engine and HEHC cycle were captured. Preliminary experimental results including firing analysis are presented for both engines. Further tuning and optimization is currently underway to fully exploit the advantages of HEHC with the X architecture engines.

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High Efficiency Hybrid Cycle Engine

Cited by 7 publications

References 0 publications

Improving Thermal Efficiency of Internal Combustion Engines: Recent Progress and Remaining Challenges

Improving Thermal Efficiency of Internal Combustion Engines: Recent Progress and Remaining Challenges

Optimal Design for New Rotary Engine with Geometric Shape Functions on Combustion Chamber and Ports

Development of a Small Rotary SI/CI Combustion Engine

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