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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 17:49 |
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Conference: Bucharest University Faculty of Physics 2022 Meeting
Section: Physics and Technology of Renewable and Alternative Energy Sources
Title:
Automotive propulsion efficiency study
Authors:
Florian POMPIERU
Affiliation:
University of Bucharest, Faculty of Physics, Bucharest-MÄgurele, Romania
E-mail
florin.pompieru@gmail.com
Keywords:
energy efficiency, automotive propulsion, greenhouse gas emission
Abstract:
Controversial and longtime-studied, internal combustion and compression ignition engines were introduced by German engineer Rudolf Diesel in the years leading up to World War I in response to the need for higher efficiency than period steam engines. Due mainly to the increased compression ratio (approx. 20: 1) and the injection of fuel directly into the combustion chamber, the engine designed by him produced two or three times more energy per cylinder capacity using peanut oil (diesel fuel did not yet exist).
More than a hundred years apart, the diesel engine has changed its characteristics very little. Although now powered by powerful oil and its derivatives, at impressive injection pressures of up to 2000 bar, supercharged without the need for a pre-combustion antechamber to avoid uncontrolled detonations and fully computerized management, Carnot cycle efficiency for ignition engines by compression remained practically the same as in the case of the first prototype.
In this case, the maximum theoretical efficiency for modern diesel engines is, which may seem reasonable, but in the following, we will show that the real efficiency of the engine in terms of mobility is significantly lower, in reality, heat losses reach up to 80- 95%. We will study the causes that lead to such low efficiency and propose solutions to streamline the propulsion system by augmenting with the efficiency devices required to be able to use the positive aspects of diesel engines in advanced hybridization with heat recovery and more modern propulsion. , such as the electric one, not before undergoing the study of plug-in hybrid propulsion systems and electric cars.
On the issue of emissions, in the case of greenhouse gases (CO2) CI engines have the advantage of high efficiency over those with spark ignition, due to almost double compression, although the combustion model, the layered one, slightly reduces this advantage. Lower fuel consumption means reduced CO2, but the specificity of excess oxygen combustion in the case of CI favors the emergence of other compounds, especially NO and NO2, also known as NOx. These emissions are amplified by the inherent load and speed variations of the wheel-coupled CI engines.
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