Gaseous and liquid fuel injector with a two way hydraulic fluid control valve

Abstract

A hydraulically actuated dual fuel injector separately injects two fuels into a combustion chamber of an internal combustion engine. In particular, the two fuels may be controlled quantities of a first liquid fuel and a second gaseous fuel that are used to fuel a diesel engine. The injector preferably begins injecting the first fuel sequentially before beginning to inject the second fuel. The dual fuel injector comprises: (a) an injector body; (b) a hydraulic fluid inlet port formed in the injector body for enabling pressurized hydraulic fluid from a hydraulic fluid source to be introduced into the interior of the injector body, said hydraulic fluid being of sufficient pressure to maintain sealing and to prevent leakage of the gaseous fuel into the hydraulic fluid; (c) a first fuel inlet port formed in the injector body for enabling a first fuel to be introduced into the interior of the injector body; (d) a first injection valve disposed within the injector body fluidly connected to the first fuel inlet port for controlling injection of the first fuel from the injector through a first fuel ejection port; (e) a second inlet port formed in the injector body for enabling a second fuel to be introduced into the interior of the injector body; (f) a second injection valve disposed within the injector body fluidly connected to the second inlet port for controlling injection of the second fuel from the injector through a second fuel ejection port; (g) a first two-way control valve which controls the flow of the hydraulic fluid to actuate the first injection valve; (h) a second control valve which controls the flow of the hydraulic fluid to actuate the second injection valve; (i) a metering device within the injector body for metering the amount of first fuel injected by the first injection valve; and (j) a seal in the injector body which prevents leakage of the second fuel within the injector body.