Numerical Investigation of the Knocking Combustion Characteristics of the N-Butanol/N-Octanol RCCI Engine

The n-butanol/n-octanol fueled reactivity-controlled compression ignition engine was numerically studied based on the KIVA-CHEMKIN code. First, knocking combustion characteristics were analyzed while functioning with a premixed n-butanol percentage of 20% (B20), since it exhibited most severe knocking. Ten local regions monitored to obtain data, such as pressure and heat release rate. oscillation quantified by band-pass filter. Second, intake valve close (IVC) timing varied investigate their effects emissions formations, well potential for mitigating results showed that strong observed B20 near cylinder wall, which indicates This consequence is mainly caused low-temperature n-octanol/n-butanol/air mixture cylinder-wall region. Increasing retarding IVC could result in an extended delay, lowered peak pressure, reduced maximum rise rate (PRR). Condition B80 −126 °ATDC improve indicated mean effective 11.7% reduce PRR 63.4% when compared condition B20.