Prechamber and Valve Gear Design for 3-Valve Stratified Charge Engines

Turkish, Michael C.

doi:10.4271/751004

Cited by 8 publications

(10 citation statements)

References 19 publications

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“…Stratified charge engines were considered an opportunity to improve an engine’s efficiency. An example of this work was reported by Turkish 6 in 1975. Increased burn rates were another area pursued for increased efficiencies.…”

Section: Introductionmentioning

confidence: 72%

Maximum efficiencies for internal combustion engines: Thermodynamic limitations

Caton

2017

International Journal of Engine Research

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The thermodynamic limitation for the maximum efficiencies of internal combustion engines is an important consideration for the design and development of future engines. Knowing these limits helps direct resources to those areas with the most potential for improvements. Using an engine cycle simulation which includes the first and second laws of thermodynamics, this study has determined the fundamental thermodynamics that are responsible for these limits. This work has considered an automotive engine and has quantified the maximum efficiencies starting with the most ideal conditions. These ideal conditions included no heat losses, no mechanical friction, lean operation, and short burn durations. Then, each of these idealizations is removed in a step-by-step fashion until a configuration that represents current engines is obtained. During this process, a systematic thermodynamic evaluation was completed to determine the fundamental reasons for the limitations of the maximum efficiencies. For the most ideal assumptions, for compression ratios of 20 and 30, the thermal efficiencies were 62.5% and 66.9%, respectively. These limits are largely a result of the combustion irreversibilities. As each of the idealizations is relaxed, the thermal efficiencies continue to decrease. High compression ratios are identified as an important aspect for high-efficiency engines. Cylinder heat transfer was found to be one of the largest impediments to high efficiency. Reducing cylinder heat transfer, however, is difficult and may not result in much direct increases of piston work due to decreases of the ratio of specific heats. Throughout this work, the importance of high values of the ratio of specific heats was identified as important for achieving high thermal efficiencies. Depending on the selection of constraints, different values may be given for the maximum thermal efficiency. These constraints include the allowed values for compression ratio, heat transfer, friction, stoichiometry, cylinder pressure, and pressure rise rate.

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Section: Introductionmentioning

confidence: 72%

Maximum efficiencies for internal combustion engines: Thermodynamic limitations

Caton

2017

International Journal of Engine Research

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“…First developed application was introduced by Harry R. Ricardo [39]. This was a 2-stroke 3-valve stratified charge SI engine known as Ricardo Dolphin engine [40,41]. A schematic view of the engine can be found in Figure 2.2.…”

Section: Active Large Pre-chamber Applicationsmentioning

confidence: 99%

“…Ricardo reported a series of successful results but also some drawbacks. At part loads he found a lack of performance and efficiency mainly due to the pneumatic actioning of the auxiliary intake valve [40,41].…”

Section: Active Large Pre-chamber Applicationsmentioning

confidence: 99%

“…The auxiliary carburetor provided a rich air-to-fuel ratio mixture while the main carburetor was set to very lean conditions. Pre-chamber nozzle was designed to provide high swirl inside the pre-chamber and it was located away from the spark plug to avoid the admission of lean mixture inside the pre-chamber [40,41].…”

Section: Active Large Pre-chamber Applicationsmentioning

confidence: 99%

“…The nozzle was designed to be flow-restrictive in order to obtain an igniting flame for the lean mixture. In this engine, dual fuel could be implemented [40,41]. A sketch of this engine can be found in Figure 2 Albert Bagnulo developed another pre-chamber application in a 3-valve stratified charge engine [41,44].…”

Section: Active Large Pre-chamber Applicationsmentioning

confidence: 99%

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Implementation and Analysis of the Pre-Chamber Ignition Concept in a SI Engine for Passenger Car Applications

Martínez Hernándiz

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The global greenhouse gas emissions increase since the start of the Industrial Revolution has become a serious hazard to human life. In addition to power generation and industry, transportation, with the rise in the total vehicle number in the last decades, is one of the main contributors to this exponential increase of global warming-causing gases. In fact, cities such as Barcelona or Madrid, among many others, are imposing traffic restrictions to mitigate this situation. However, mankind is still on time to reverse this negative tendency and fix the environmental issue for the upcoming generations.The main goal of the present Thesis focuses on the study, implementation and analysis of the passive pre-chamber ignition concept in a near-future light-duty passenger car application. To be more specific, the investigation addresses the physical phenomena involving the combustion process when pre-chamber ignition system is used in a spark-ignition engine. Then, some strategies to improve thermal efficiency while employing this concept are applied. Finally, with all the knowledge gathered, basic guidelines for a pre-chamber pre-design are presented.The first approach to the concept consists of its direct implementation in the engine, obtaining experimental results in three different operating conditions in terms of engine load and speed. Furthermore, different prechamber geometries are also evaluated. Although its direct implementation is relatively straightforward by exchanging the spark plug, understanding some of the relevant phenomena related to the combustion process, such as gas exchange or jet-tip penetration, is extremely difficult without the support of computational tools. This is the main reason supporting the use of 1D numerical tools in the present Thesis, since with proper modeling based on experimental data, further knowledge can be obtained in those situations where experimental evaluations are not feasible. These 1D tools have the benefits of their low computational cost and their ability to provide reasonably good results in a short period of time. ix xv[8] F. D. Sabatino, P. J. Martinez-Hernandiz, R. N. Rosa, and I. Ekoto. "Investigation of the effects of passive pre-chamber nozzle pattern and ignition system on engine performance and emissions". International Journal of Engine Research 0 (0), 2022.

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