ControlofCombustionTiminginHCCIEngine.pptxVIP

Control of Combustion Timing in HCCI EngineReporter：Haipeng YuTime：2016-03-171243Research BackgroundSummary and ProspectMPC for Combustion Timing in HCCIEffects of Intake Temp on HCCI EngineContents1. Research Background Emissions regulations and technologies adoptedFig. 1. Evolution of Emissions Regulations (USA, Heavy-duty diesel engine)1. Research BackgroundFig 2. Diagram showing the operation of a 4-stroke SI engine. Labels:1?‐ Induction2?‐ Compression3?‐ Power4?‐ ExhaustFig 3. Different combustion mode traces on the φ-T mapNotice: HCCI is one of the low temperature combustion (LTC) mode1.1 Fundamental of HCCIHC+SISC+CIGasoline EngineHCCIDiesel EngineHomogeneous charge compression ignition?(HCCI) is a form of? internal combustion?in which well-mixed?fuel?and?oxidizer?(typically air) are compressed to the point of auto-ignition. HCCI combines characteristics of conventional?gasoline engine?and?diesel engines. Gasoline engines combine?homogeneous charge(HC) with?spark ignition?(SI), abbreviated as HCSI. Diesel engines combine?stratified charge?(SC) with?compression ignition(CI), abbreviated as SCCI1.2 Advantages and Disadvantages of HCCI[1]Advantages Since HCCI engines are fuel-lean, they can operate at diesel-like compression ratios (15), thus achieving 30% higher efficiencies than conventional SI gasoline engines. Homogeneous mixing of fuel and air leads to cleaner combustion and lower emissions. Because peak temperatures are significantly lower than in typical SI engines,?NOx?levels are almost negligible. Additionally, the technique does not produce?soot. HCCI engines can operate on gasoline, diesel fuel, and most alternative fuels. HCCI avoids throttle losses, which further improves efficiency.Disadvantages Achieving cold start capability. High in-cylinder peak pressures may damage the engine. High heat release and pressure rise rates contribute to engine wear. Autoignition is difficult to control, unlike the ignition event in SI and?diesel engines, which a