The present study investigates theoretically the effects of gasoline fumigation on single-cylinder diesel engine performance and emissions. The results indicate that a premixed charge can be obtained by early injection of gasoline because of the high volatility of gasoline. More homogenous mixture was obtained and the fuel burned faster and efficient. The smoke emission was reduced and engine output was increased. Coupling with EGR technique could reduce the NOx emissions simultaneously.

This study investigates the potential of controlling diesel homogenous charge compression ignition (HCCI) combustion by blending ethanol, which inhibits low temperature oxidation offering the possibility to control ignition in HCCI combustion. The simulation results from a multi-zone model show that the ethanol reduces the key active intermediate radicals OH, CH2O, H2O2, delays the low temperature oxidation reaction (LTR), reduces the heat released during LTR stage. As a result, it retards the main combustion stage.

A numerical study is conducted in a port fuel-injection, spark-ignition engine fuelled with 1-butanol at different fuel/air equivalence ratios and inlet air temperatures. The effect of fuel/air equivalence ratio and inlet air temperature on the engine performance and emission characteristics is analyzed. The modeling results show that the incylinder pressure and temperature increases with the increase of fuel/air equivalence ratio. The slightly lean mixtures offer the maximum level of NOX emissions. In addition, preheating the inlet air can increase the incylinder pressure peak value and NOX emissions.

To enhance the lean combustion of methane homogenous charge compression ignition (HCCI) engine and expand the lean-burn limit, a non-equilibrium plasma kinetic model has been used to study the discharge process of methane-air mixture numerically. The effect of the discharge productions on the methane HCCI combustion are studied numerically by using a CHEMKIN-based multi-zone model. The simulation results show that the discharge produced reactive radicals, such as H, O and CH3. These radicals can enhance the combustion of CH4 fueled HCCI significantly. Introduction of 1% (volume fraction of the fuel) of H reduces the ignition delay time of HCCI combustion (with equivalence fuel / air ratio of Φ = 0.5) by about 13 crank angle degrees (°CA), adding the same amount of O reduces the ignition delay time by about 10°CA. Further research shows that, with the increase in the above radicals, the combustion enhancement becomes stronger.

The potential of controlling premixed compression ignition (PCI) combustion by two fuels with different ignitability and volatility was studied numerically by a three-dimensional computational fluid dynamics (CFD) model. The results indicate that the addition of gasoline to diesel fueled PCI engine can retard the ignition timing, lower the in-cylinder temperature, and reduce the exhaust emissions.