To further improve fuel efficiency and output, ZR15DDTe engine uses Nissan's unique STARC*2 concept paired with a large turbocharger.
The STARC concept is the embodiment of research findings that highlight the importance of controlling airflow toward the spark plug inside the combustion chamber to improve ignition. The concept involves managing airflow so that the discharge channel from the spark plug remains stable, guiding combustion effectively and providing a stable combustion even with a high EGR rate.
By using cold spray technology to integrate the valve seat into the engine's intake port, the ideal port shape is achieved, allowing air to be forcefully directed into the cylinder with a strong tumble flow. Additionally, the piston crown is precisely shaped to maintain tumble flow during compression, thus ensuring ignition with a strong spark and stable combustion.
The large turbocharger forces a substantial amount of compressed exhaust gas and air into the cylinder, boosting output while also improving the engine's thermal efficiency.