Engine system and operating method using matched fuel injector and piston for optimized spray jet interaction with combustion bowl

An engine system comprising:

• an engine housing having a combustion cylinder formed therein;
• a piston movable in the combustion cylinder between a bottom-dead-center position and a top-dead-center position to increase in-cylinder pressure to an autoignition threshold for air and an injected liquid fuel;
• the piston defining a piston center axis and including a piston end face forming an annular piston rim extending circumferentially around a combustion bowl, and a center cone within the combustion bowl;
• a fuel injector including a nozzle tip within the combustion cylinder, and spray outlets formed in the nozzle tip;
• and
• the combustion bowl having a reentrant profile, the center cone defining a cone angle, and the spray outlets numbering exactly seven and having among them a uniform spray angle smaller than the cone angle so as to form a glancing spray jet impingement pattern upon the center cone when the piston is at the top-dead-center position.

A combustion system for an engine comprising:

• a fuel injector having exactly seven spray outlets formed therein;
• a piston defining a piston center axis and including a piston end face forming a combustion bowl having a bowl floor and a bowl outer wall, a center cone within the combustion bowl defining a cone angle, and an annular piston rim;
• the piston further including a reentrant protrusion extending circumferentially around the combustion bowl, and the annular rim and the bowl outer wall intersecting at the reentrant protrusion;
• a fuel injector including a nozzle tip having exactly seven spray outlets formed therein and each defining a spray axis, the spray outlets spaced circumferentially around the center axis and arranged at a uniform spray angle that is smaller than the cone angle;
• and
• the piston being movable between a bottom-dead-center position and a top-dead-center position, and the bowl floor being radiused to form a toroidal shape and intersected by the spray axes at the top-dead-center position of the piston.