Advanced ignition technology for the achievement of high thermal efficiency of internal combustion engine

Abstract

efficiency of the latest gas engine was a lower heating value (LHV) of almost 50 %. This is because of the application of technologies such as lean burn and mirror cycles. [5] Even though cogeneration has a high total energy-utilization efficiency, the practical application of conventional cogeneration is suitable for cases that require a relatively large amount of heat because the proportion of heat obtained from cogeneration is still large. In general, electricity is a preferred product than thermal energy. Therefore, it is important to increase the thermal efficiency for electrical power generation to accelerate the adoption of cogeneration technology. 2 Technological issues affecting natural gas engines 2.1 Thermal efficiency of gas engines and future direction of technological development The improvements in the thermal efficiency of gas engines are important for the promotion of gas engine-based cogeneration installation. Obviously, the maximum thermal efficiency is limited by the Carnot cycle according to thermodynamics. The actual gas engine is an irreversible engine, and the Otto cycle model, which is closer to a real engine, is used to understand its fundamental behavior. In the Otto cycle, fuel is supposed to burn at the location of the piston's top position, which corresponds to the maximum compression. On the contrary, it is supposed to be exhausted at the bottom piston position, which corresponds to the maximum expansion. The thermal efficiency of the Otto cycle th is expressed in the following equation:

Experimental characterisation of the thermal energy released by a Radio-Frequency Corona Igniter in nitrogen and air

“…The pressing request, in term of pollutant emissions and carbon footprint, forces the automotive industries to introduce and develop innovative technologies to allow the internal combustion engine to be competitive in the modern world market for the next years. The need for exhaust gas recirculation (EGR) [1] or ultra-lean combustion [2] requires the development of advanced and innovative ignition systems and strategies, by enhancing the thermal energy conversion efficiency, that increases quite linearly with λ [3], and allowing operating conditions characterised by poor pollutant emissions [4,5]. The water injection is also an advanced technology able to improve the combustion in the modern engines for the general performance enhancement [6,7] as well as the thermal efficiency improvement [8,9] or the knocking control strategies [10].…”

“…The early fluctuations of the thermodynamics and fluid-dynamics operating conditions around the spark region are the main causes of the cycle-to-cycle variation [24] while large flame kernels are less subject to conditioning [25]. Furthermore, dielectric insulation becomes an issue once higher discharge voltage is required to achieve the breakdown conditions, as in the modern engines for the high levels of boosting [5].…”

Термодинамический Цикл Брайтона С Обратимой Химической Реакцией

“…Удаление части теплоты Q out необходимо для возврата рабочего вещества в начальное состояние, или для замыкания термодинамического цикла. Современные подходы к увеличению КПД основаны на выборе новых термодинамических циклов [3][4][5], подборе рабочих веществ [6][7][8] и снижения потерь энергии в окружающую среду [9][10][11]. Но если рабочее вещество может менять свои свойства в результате химического превращения, то происходит качественное изменение: в процессе преобразования теплоты Q in в работу W начинает участвовать химическая работа W ch .…”