Honda Motor Corporation has developed a new naturally aspirated in-line 4-cylinder direct injection gasoline engine for C segment sedans that combines high environmental performance and power output. Development time and cost were greatly reduced by utilizing basic structures and components that had previously been developed engine for hybrid vehicles. In addition to the environmental performance at which hybrid engines excel, the driving performance required from a pure gasoline engine for C segment sedans with a low environmental impact was aimed to achieve by optimizing the shape of the combustion chamber to obtain rapid combustion, adjusting intake and exhaust valve timing, employing fuel injection control and adopting a two-piece water jacket that protects the exhaust system component by lowering the exhaust gas temperature at high load.
As a result, the newly developed engine achieves a maximum thermal efficiency of 40% with knock suppression effect through rapid combustion technology and large-capacity externally cooled EGR and meets the North American particulate matter (PM) regulation of 1 [mg/mile] with the wall surface fuel adhesion zero concept that directs injected fuel to the center of the tumble flow vortex. Furthermore, by adopting a two-piece cooling jacket structure, the stoichiometric combustion operating range has been expanded, achieving the target output of 112 kW while significantly improving environmental performance.