Nakamura, J., Akabane, A., Kitamura, K., and Sasaki, Y., "Improvement of Spray Characteristics in Port Injectors," SAE Technical Paper 2012-32-0071, 2012, doi:10.4271/2012-32-0071.
Fuel spray injected by a port injector has significant effects on engine power output and combustion efficiency. For this reason, it is necessary to atomize fuel into fine droplets and accurately supply it without being susceptible to any changes in temperature or negative pressure affected by engine. This document introduces an atomization technique with optimized layout of nozzle holes and drastically reduced pressure loss (energy loss) in the flow under a needle valve seat. It also describes an injector having a short fuel flow path and a small dead volume under the valve seat, which can have good resistance against any changes in temperature and negative pressure.