CO2 Reduction by Shorter Burn Duration – Optical examination of combustion in a high-pressure, high-temperature chamber (FVV BDV (FW-Nr. 6014813))
Third Party Funds Group - Sub project
Acronym:
FVV BDV (FW-Nr. 6014813)
Start date :
01.10.2022
End date :
31.03.2025
Overall project details
Overall project
CO2 Reduktion durch Brenndauerverkürzung
Overall project speaker:
Project details
Short description
In the conventional diesel combustion
process, there is further efficiency potential in the reduction of wall
heat losses and in the shortening of the combustion period. With regard
to potential measures for reducing the combustion period, there is still
a fundamental need for research.
The combustion process in diesel engines can be divided into three time components:
-
The first time component of combustion usually proceeds premixed and
thus quite rapidly (i.e., with a high heat release rate). Here,
ignition as the progress-determining mechanism for combustion is
primarily controlled by reaction kinetics.
- The second part
of the combustion process is primarily mixture-controlled, i.e.
controlled by macroscopic turbulence (injection and swirl) and by
diffusion at the molecular level. The turbulent kinetic energy
introduced by the injection has a considerable influence. This leads to a
considerable acceleration of the combustion conversion, especially in
engines with direct injection.
- The third time component is
influenced both by the decaying turbulence after the injection process
and by diffusion, i.e. the concentration differences in the mixture.
Despite the high temperatures, the diffusion processes do not occur
sufficiently quickly, so that this third time fraction of combustion
proves to be relatively long, even in DI diesel engines, and thus
unfavorable for thermodynamic efficiency. In contrast to the second
combustion phase, the accelerating part due to a sufficient turbulence
level is missing here.
In the project, simulative and
experimental investigations are carried out on innovative measures to
shorten the diffusive burnout phase in diesel engines.
Scientific Abstract
In the conventional diesel combustion process, there is further efficiency potential in the reduction of wall heat losses and in the shortening of the combustion period. With regard to potential measures for reducing the combustion period, there is still a fundamental need for research.
The combustion process in diesel engines can be divided into three time components:
- The first time component of combustion usually proceeds premixed and thus quite rapidly (i.e., with a high heat release rate). Here, ignition as the progress-determining mechanism for combustion is primarily controlled by reaction kinetics.
- The second part of the combustion process is primarily mixture-controlled, i.e. controlled by macroscopic turbulence (injection and swirl) and by diffusion at the molecular level. The turbulent kinetic energy introduced by the injection has a considerable influence. This leads to a considerable acceleration of the combustion conversion, especially in engines with direct injection.
- The third time component is influenced both by the decaying turbulence after the injection process and by diffusion, i.e. the concentration differences in the mixture. Despite the high temperatures, the diffusion processes do not occur sufficiently quickly, so that this third time fraction of combustion proves to be relatively long, even in DI diesel engines, and thus unfavorable for thermodynamic efficiency. In contrast to the second combustion phase, the accelerating part due to a sufficient turbulence level is missing here.
In the project, simulative and experimental investigations are carried out on innovative measures to shorten the diffusive burnout phase in diesel engines.
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Funding Source
