Gasoline DICI Engine Operation in the LTC Regime Using Triple- Pulse Injection

Effects of In-Cylinder Mixing on Low Octane Gasoline Compression Ignition Combustion

“…Ra et al [25] performed extensive numerical studies on GCI combustion to investigate the effects of injection parameters, gas temperatures, boost pressure and exhaust gas recirculation (EGR) on combustion characteristics such as combustion phasing and important emissions. As a specific example, they [15] have demonstrated that triple injection GCI helped achieving high load operation through parametric simulations. Recently, Badra et al [26] reported a numerical study on the optimization of the spray models for outwardly opening hollow cone spray and the effects of primary reference fuel (PRF) and toluene primary reference fuel (TPRF) chemical surrogates on the combustion phasing of GCI engine running on naphtha fuel.…”

“…This combustion mode has been gaining increasing attention over the last decade due to its potential of achieving diesel-like thermal efficiencies with significantly reduced engine-out nitrogen oxides (NOx) and soot emissions. Recent studies [5,6,7,8,9,10,11,12,13,14,15,16,17,18] reported that GCI combustion occurs as a series of autoignition events with minor contributions from the flame fronts. This is usually achieved by controlling the autoignition timing by manipulating equivalence ratio stratification levels within the cylinder through late injection in the compression stroke, in contrast to homogeneous charge compression ignition (HCCI) [19,20,21,22] and premixed ignition [23,24] engines where the fuel and air are fully mixed prior to entering the combustion chamber.…”

Spray Modeling for Outwardly-Opening Hollow-Cone Injector

“…Instead, the spray is considered many small solid cone injections along a circular liquid sheet in favor of the experimentally observed string-like structure of the outwardlyopening hollow-cone spray injection. Assuming that the cylindrical liquid blobs are attached each other, the initial SMD (D 0 ) for the KHRT breakup model is computed by (3) By simplifying the equation, the initial SMD is computed by (4) The equation (4) is used as an initial SMD through this study. This value is not a constant, but a function of liquid film thickness, which is computed from the given mass flow rate and computed injection velocity.…”

“…GCI engines in general operates at low temperature combustion (LTC) conditions that have been gaining increasing attention over the last decade due to its potential of achieving diesel-like thermal efficiencies with significantly reduced engine-out nitrogen oxides (NOx) and soot emissions. Recent studies [3,4,5] reported that GCI combustion occurs as a series of autoignition events with minor contributions from the flame fronts. As such, successful GCI operation is usually achieved by controlling the autoignition timing by manipulating equivalence ratio stratification levels within the cylinder through late injection in the compression stroke.…”

Hollow-Cone Spray Modeling for Outwardly Opening Piezoelectric Injector

“…3,4 Due to the demand of precise injection control, an outwardly-opening hollow-cone injector controlled by accurate piezoelectric actuator was developed for modern GDI engines although inwardly-opening pressure-swirl injectors have been widely used. 5 However, understanding the detailed spray characteristics of this promising injector is still challenging and few modeling studies are available.…”