A hydro-diesel engine system, including: (a) a hydrogen gas supply and a liquid diesel fuel supply; (b) a bubbilizer configured to agitatedly mix some of the hydrogen gas into diesel fuel to form a mixture of small bubbles of hydrogen gas in the liquid diesel fuel which is then sent into a hydro-diesel engine; together with (c) a system for chemically mixing some of the hydrogen gas with the diesel fuel prior to the diesel fuel entering the bubbilizer.

An internal combustion engine system is described herein. The system uses a pilot fuel to assist in the ignition of the primary fuel or uses a pilot fuel rather than a primary fuel in some instances. The pilot fuel is stored in one or more pilot fuel storage tanks that are actively managed to maintain a desired physical state of the pilot fuel stored in the one or more storage tanks. A controller detects conditions within the one or more pilot fuel storage tanks and issues control commands depending on the detected conditions. The conditions can include a temperature, a pressure, or a level of the pilot fuel stored in the pilot fuel storage tanks.

A dual fuel system includes a first fuel supply of a first fuel, a second fuel supply of a second fuel, and a variable-output fuel pump. A fuel injector in the dual fuel system includes a combined-fuel outlet passage, a nozzle check movable to open and close the combined-fuel outlet passage to nozzle outlets, and a check valve positioned at least partially in a first fuel passage connected to the first fuel supply by way of the variable-output fuel pump. The first fuel may include a compression-ignition fuel and the second fuel may include an alcohol fuel. Varying output of the fuel pump during an off-cycle of a cam actuating a plunger in the fuel injector meters the first fuel to the fuel injector for forming a fuel charge for injection. Related apparatus and methodology is also disclosed.

A dual fuel system includes a first fuel supply of a first fuel, a second fuel supply of a second fuel, and a variable-output fuel pump. A fuel injector in the dual fuel system includes a combined-fuel outlet passage, a nozzle check movable to open and close the combined-fuel outlet passage to nozzle outlets, and a check valve positioned at least partially in a first fuel passage connected to the first fuel supply by way of the variable-output fuel pump. The first fuel may include a compression-ignition fuel and the second fuel may include an alcohol fuel. Varying output of the fuel pump during an off-cycle of a cam actuating a plunger in the fuel injector meters the first fuel to the fuel injector for forming a fuel charge for injection. Related apparatus and methodology is also disclosed.

A fuel evacuation system includes an outer fluid pathway and an inner fluid pathway arranged therein. The system also includes a controller to control flows of gas and liquid fuel from respective first and second sources, and a sealing member coupled to the inner and outer fluid pathways, where the sealing member is operable between a first and at least one second position. In the first position, the sealing member enables the outer fluid pathway to be fluidly independent from the inner fluid pathway. In the at least one second position, the sealing member couples the outer fluid pathway to the inner fluid pathway. In a first mode, the controller causes liquid fuel from the inner fluid pathway to flow to the outer fluid pathway. In a second mode, the controller is configured to cause gas from the outer fluid pathway to flow to the inner fluid pathway.