|
Gasoline direct injection engines have become popular
powertrains for passenger car segment worldwide. The technology
is known for its characteristics of high power output, greater
thermal efficiency and improved fuel economy. Due to its
capability of being operated under two combustion mode by
varying the fuel injection timing, it is emerging as a widely
adopted engine technology. GDI has two combustion concepts:
stratified charge operation (Part load) and homogeneous
stoichiometric operation (Full load). In stratified charge
operation, fuel is injected late in the compression stroke
creating a rich mixture near the spark plug and overall the
mixture is lean. In homogeneous stoichiometric operation, fuel
is injected early in the intake stroke so that homogeneous
mixture is created inside the combustion chamber. We can use
homogenous mode during high torque requirement and stratified
charge mode during low torque requirement. In ERL, the
homogenous mode of combustion has been explored. A comprehensive set
of experiments were conducted to understand the
inter-relationships between gasohols and baseline gasoline in a
GDI engine. In this context, three gasohols (15% (v/v) blends of
methanol/ethanol/butanol with 85% (v/v) gasoline were
investigated.
-
Macroscopic and microscopic spray characteristics of
gasohols and baseline gasoline were carried out.
-
Engine performance, combustion and emission characteristics
of GDI engine were investigated at different operating
conditions.
-
Detailed particulate morphology characterization was carried
out which included ICP-OES, FE-SEM, HETEM, FTIR and Raman
Spectroscopy.
-
Implementation of Phase Doppler Interferometry (PDI) in an
optical engine to find real time spray droplet
velocity-diameter distributions at optimum engine operating
conditions.
-
Different primary alcohols were compared for combustion,
performance and emissions characterisation in dual fuel
injection mode, where alcohols were injected in port and
gasoline was injected directly into the cylinder
Optical investigation for combustion analysis in homogeneous and
stratified mode of operation can be done for further detailed
investigation and optimizing the engine performance. |
