Harada, M., Kadota, T., and Sugiyama, Y., "Nissan NAPS-Z Engine Realizes Better Fuel Economy and Low NOx Emission," SAE Technical Paper 810010, 1981, doi:10.4271/810010.
Nissan Motor Co., Ltd. has succeeded in developing a highly reliable, simple-mechanism engine that can be used with a carburetor system, a fuel injection system or an LPG system. During the 1980 certification programs conducted in the United States and Japan, this engine was unrivaled in its low emissions and excellent fuel economy.Such high fuel efficiency is realized by the adoption of a fast-burn combustion system. Fast-burn combustion is made possible by the development of a high-speed swirl system and a two-point ignition system. Furthermore, an EGR system with a VVT valve has also been developed to afford precise control over the EGR, which is what optimizes the performance characteristics of this engine. Uniform EGR distribution is realized through improvements made in the intake manifold.Because of its low emission levels and high fuel efficiency, this engine is expected to find wide utilization in meeting the stringent requirements for energy conservation and environmental protection.