Direct operated velocity controlled nozzle valve for a fluid injector

A fuel injector nozzle valve velocity control apparatus, comprising:

• a housing having an injection orifice;
• a high pressure fuel source;
• a check including an upper end and a lower end adjacent said injection orifice, said check being movable in response to said high pressure fuel between an open position allowing high pressure fuel communication with said injection orifice and a closed position blocking said communication with said injection orifice;
• a low pressure fuel passage;
• a high pressure fuel passage communicating high pressure fuel to said check lower end and selectably communicating high pressure fuel to said check upper end;
• and
• an actuating valve selectively movable between a sealing position and an injecting position for selectively communicating said high pressure fuel passage to said check upper end or said low pressure fuel passage to said check upper end, said actuating valve at its injecting position including a first flow area restriction for controlling the rate of fuel pressure change to said check upper end.

A fuel injector nozzle valve velocity control apparatus, comprising:

• a housing having an injection orifice and defining a check cavity;
• a check including an upper end extending into said check cavity and a lower end adjacent said injection orifice, said check being movable in response to high pressure fuel between an open position allowing high pressure fuel communication with said injection orifice and a closed position blocking said communication with said injection orifice, said check upper end dividing said check cavity into a lower check cavity and an upper check cavity;
• a low pressure fuel supply;
• a high pressure fuel passage communicating high pressure fuel to said check lower end and selectably communicating high pressure fuel to said lower check cavity;
• a damping port allowing fuel communication between said upper check cavity and said low pressure fuel passage, said damping port including a second flow area restriction for controlling the rate of fuel pressure change within the upper check cavity thereby controlling the rate of movement of the check between its open and its closed positions;
• and
• an actuating valve for selectively controlling communication of high pressure fuel to said lower check cavity or low pressure fuel to said lower check cavity.

A method of injecting fuel into a combustion chamber of an internal combustion engine using a fuel injector having an injector body, a check disposed in the injector body having a check upper end and a check lower end and movable between injecting and non-injecting positions, a spring urging the check into the non-injecting position and means for selectively communicating either high or low fluid pressures to the check ends, comprising the steps of:

• (a.) controlling the communicating means to cause the high fluid pressure to be applied to the check lower end and low fluid pressure to be applied to the check upper end allowing the spring to retain the check in non-injecting position;
• (b.) thereafter controlling the communicating means to cause the high fluid pressure to be applied to the upper check end while the high fluid pressure is being applied to the lower check end so that the check is moved to the injecting position against the urging of the spring;
• and
• (c.) thereafter controlling the communicating means to cause the low fluid pressure to be applied to the upper check end and high fluid pressure to be applied to the lower check end so that the check is moved to the non-injecting position in response to the urging of the spring.

A direct-operated check control apparatus, comprising:

• a source of high pressure fluid;
• a low fluid pressure drain;
• a housing having an injection orifice;
• a check having a check upper end, and being movable between an open position allowing high pressure fuel communication with said injection orifice and a closed position blocking said communication with said injection orifice;
• biasing means acting on said check to bias said check towards said closed position;
• actuating means for controlling communication of said high pressure fluid or said low fluid pressure drain to said check upper end, thereby utilizing only said biasing means to retain the check in said closed position and utilizing only high fluid pressure to move said check to said open position.