Hydraulically actuated gaseous or dual fuel injector

A hydraulically actuated fuel injection apparatus for injecting a pilot fuel and a high pressure main fuel into an internal combustion engine, said apparatus comprising:

• (a) an injector housing defining a valve chamber with an injector nozzle at an end proximate to a combustion chamber, said injector nozzle having at least one opening into the combustion chamber;
• (b) a first displaceable injection valve within said valve chamber and biased by a spring into seating against a valve seat formed in the valve chamber for injecting the pilot fuel into the combustion chamber;
• (c) a second displaceable injection valve within said valve chamber and biased by a spring into seating against a valve seat formed in the valve chamber for injecting the main fuel into the combustion chamber;
• (d) a first port for introducing the pilot fuel into the valve chamber;
• (e) a second port for introducing the main fuel into the valve chamber;
• (f) an actuator mechanism for generating a rising hydraulic pressure pulse in a hydraulic fluid to displace the first injection valve upon the hydraulic fluid reaching a first predetermined pressure level and separately displacing the second injection valve upon the hydraulic fluid reaching a second predetermined pressure level thereby injecting the pilot fuel and the main fuel to be injected into the combustion chamber;
• and
• (g) a pressure limiting device for relieving the pressure of the hydraulic fluid upon the pressure reaching a predetermined level.

A method of injecting a main fuel into an internal combustion engine comprising:

• (a) introducing the main fuel into a valve chamber;
• (b) introducing a hydraulic fluid into the valve chamber;
• (c) generating a rising hydraulic pressure in the hydraulic fluid to actuate a displaceable injection valve, thereby enabling the main fuel to be injected into a combustion chamber;
• and
• (d) relieving the pressure of the hydraulic fluid pressure reaches a predetermined level.

A method of injecting a pilot fuel and a main fuel into an internal combustion engine comprising:

• (a) introducing the pilot fuel into a valve chamber;
• (b) introducing the main fuel into the valve chamber;
• (c) introducing a hydraulic fluid into the valve chamber;
• (d) generating a rising hydraulic pressure in the hydraulic fluid to displace a first injection valve upon the hydraulic fluid reaching a first predetermined pressure level, thereby enabling the pilot fuel to be injected into the combustion chamber, and separately displacing a second injection valve upon the hydraulic fluid pressure reaching a second predetermined level, thereby injecting the main fuel into the combustion chamber;
• (e) relieving the pressure of the hydraulic fluid when the pressure reaches a third predetermined level.