An ammonia mixed combustion engine 1 that operates by burning ammonia and a hydrocarbon liquid fuel causes a control unit 2 to implement at least one of decrease or increase in an air excess ratio in fuel, advance or retard in injection timing of the liquid fuel, and decrease or increase in injection pressure of the liquid fuel in accordance with increase or decrease in a mixed fuel burning ratio of ammonia in the fuel.

A supplemental fuel system for a machine with an engine is configured to monitor a voltage of a power supply of the machine based on voltage data acquired by a voltage sensor where the power supply is configured to receive power from an alternator driven by the engine, compare the voltage to a voltage threshold, and control an electronic lock off valve positioned between a supplemental fuel tank and an air supply system for the engine such that the electronic lock off valve is (i) closed to prevent a supplemental fuel from being provided from the supplemental fuel tank to the to the air supply system in response to the voltage being less than the voltage threshold and (ii) open or openable to permit the supplemental fuel to be provided to the air supply system in response to the voltage being greater than the voltage threshold.

A dual fuel system includes a fuel injector having a fuel pressurization plunger, and a fueling control unit structured to determine a fuel bulk modulus term based upon a volume change value (dV) and a pressure change value (dP) for a fuel pressurized in the fuel injector. The fueling control unit is further structured to determine fuel injector control commands by way of map lookups on fueling maps selected on the basis of the fuel bulk modulus term. Related apparatus and methodology are also disclosed.

A dual fuel system includes a fuel injector having a fuel pressurization plunger, and a fueling control unit structured to determine a fuel bulk modulus term based upon a volume change value (dV) and a pressure change value (dP) for a fuel pressurized in the fuel injector. The fueling control unit is further structured to determine fuel injector control commands by way of map lookups on fueling maps selected on the basis of the fuel bulk modulus term. Related apparatus and methodology are also disclosed.

A method for determining a fuel characteristic, the method including receiving a gaseous fuel within a gaseous fuel rail of a dual fuel engine configured to run on at least the gaseous fuel and a diesel fuel. The method may include receiving a pressure signal from a pressure sensor indicating a pressure of the gaseous fuel within the gaseous fuel rail, and identifying at least one of an amplitude and a phase of the pressure signal, The method may further include determining a characteristic of the fuel within the fuel rail based on the amplitude or the phase of the pressure signal, and, based on the determined characteristic of the fuel, modifying an operational parameter of the dual fuel engine.

A method of regulating and injecting a gaseous fuel in an internal combustion engine includes regulating a pressure of the gaseous fuel to an injection pressure at an engine load and an engine speed; and injecting within 90 crank angle degrees of top dead center during a compression stroke of the internal combustion engine an injected quantity of the gaseous fuel into a combustion chamber at the injection pressure; where the gaseous fuel comprises hydrogen; where the injection pressure equals a product of a peak cylinder pressure multiplied by a multiplication factor, the multiplication factor within a range of 1.15 and 1.4; and where the injected quantity of the gaseous fuel is burned in a diffusion combustion mode.

A fuel system for a machine with an engine is configured to monitor a voltage of a power supply of the machine based on voltage data acquired by a voltage sensor where the power supply is configured to receive power from an alternator driven by the engine, compare the voltage to a voltage threshold, and control an electronic lock off valve associated with a fuel tank such that the electronic lock off valve is (i) closed to prevent a fuel from being provided from the fuel tank to the to the engine in response to the voltage being less than the voltage threshold and (ii) open or openable to permit the fuel to be provided to the engine in response to the voltage being greater than the voltage threshold.

A method for determining a fuel characteristic, the method including receiving a gaseous fuel within a gaseous fuel rail of a dual fuel engine configured to run on at least the gaseous fuel and a diesel fuel. The method may include receiving a pressure signal from a pressure sensor indicating a pressure of the gaseous fuel within the gaseous fuel rail, and identifying at least one of an amplitude and a phase of the pressure signal, The method may further include determining a characteristic of the fuel within the fuel rail based on the amplitude or the phase of the pressure signal, and, based on the determined characteristic of the fuel, modifying an operational parameter of the dual fuel engine.