Effect of Reverse Squish on Fuel Spray Behavior in a Small DI Diesel Engine under High Pressure Injection And High Charging Condition

摘要

Modern small DI diesel engines are operated at high loads and high speeds. In these engines the spray spreading on the cavity walls during the main combustion is kept approximately constant at all engine speeds to optimize the air utilization. However, spray spreading on the wall during the early and late part of combustion changes with engine speed due to the changes in air motion. At the end of impingement much of the spray moves outside the cavity due to a strong reverse squish when the injection timing is set near TDC. This causes incomplete combustion of fuel and increase emissions of HC and soot. Therefore, the study of the behavior of Spray affected by the reverse squish is very important.