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Download fileInfluence of the variable valve timing strategy on the control of a homogeneous charge compression (HCCI) engine
conference contribution
posted on 2011-05-25, 09:32 authored by Nesa Milovanovic, Rui Chen, J.W.G. TurnerHomogeneous Charge Compression Ignition (HCCI) engine
concept has the potential to be high efficient and to produce
low NOx and particulate matter emissions. However,
the problem of controlling the combustion over the entire
load/speed range limits its practical application. The HCCI
combustion is controlled by chemical kinetics of the charge
mixture, with no influence of the flame diffusion or turbulent
propagation. Therefore, to achieve a successful control of the
HCCI process, the composition, temperature and pressure of
the charge mixture at IVC point have to be controlled. The
use of the variable valve timing strategy that enables quick
changes in the amount of trapped hot exhaust gases shows
the potential for the control of the HCCI combustion.
The aim of this paper is to analyse influence of the variable
valve timing strategy on the gas exchange process, the process
between the first valve open event (EVO) and the last valve
closing event (IVC), in a HCCI engine fuelled with standard
gasoline fuel (95RON). The gas exchange process affects the
engine parameters and charge properties and therefore plays
a crucial role in determining the control of the HCCI process.
Analysis is performed by the experimental and modelling
approaches. The single-cylinder research engine equipped
with the fully variable valve train (FVVT) system was used
for the experimental study. A combined code consisting of
a detailed chemical kinetics code and one-dimensional fluid
dynamics code was used for the modelling study.
The results obtained indicate that the variable valve timing
strategy has a strong influence on the gas exchange process,
which in turn influences the engine parameters and the cylinder
charge properties, hence the control of the HCCI process.
The EVC timing has the strongest effect followed by the IVO
timing, while the EVO and IVC timings have the minor effects.
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School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Aeronautical and Automotive Engineering