One-dimensional simulation analysis of PFI-SI engine for fuel economy improvement by employing VVT/VCR strategies.

摘要

Variable Valve Timing (VVT) strategy on both intake and exhaust valves has a pivotal influence on the specific fuel consumptions and engine performance. In addition to this, fuel economy can also be enhanced by the application of Variable Compression Ratio (VCR) strategy.; My thesis work presents three possible strategies to enhance fuel economy improvement: (1) A possible VVT strategy Early Intake Valve Opening (EIVO) and Late Exhaust Valve Closure (LEVC) that alters the valve overlap to reduce fuel consumption; (2) A two-position VCR system that improves fuel conversion factor to realize fuel economy; (3) A strategy that combines above two technologies to produce a complementary effect on each other to enhance fuel economy.; AVL BOOST a 1D engine gas exchange and cycle simulation code has been used to model 1.8L 4-Cylinder Port-Fuel Injection (PFI) engine to get fuel economy gains at part-load points. 1D Model has been validated with Experimental results for all three strategies from FORD MOTOR COMPANY. Therefore, the simulation provided essential information to understand engine thermodynamic process and VVT system development.