US Patent 11773792 Multi-fuel injection system and injector

A multi-fuel injector includes a primary fuel inlet configured to receive a liquid primary fuel, a pilot fuel inlet configured to receive a liquid pilot fuel that is a different fuel than the primary fuel, and a spill valve in fluid communication with the primary fuel inlet. The fuel injector also includes a control valve configured to control a pressure of fluid within a hydraulic control chamber, and an injection valve abutting the hydraulic control chamber, the injection valve being configured to move to an injection position to inject both the primary fuel and the pilot fuel.