The invention relates to a method for operating an internal combustion engine (1), which comprises at least one combustion chamber (3) and an injector (5) which is assigned to the combustion chamber (3) and intended for introducing a first gaseous fuel into the combustion chamber (3), wherein a second liquid fuel is used for operation of the injector (5), wherein in a start-up operation of the internal combustion engine (1) the injector (5) is actuated in at least one operational cycle, avoiding complete combustion of the fuel introduced into the combustion chamber (3) via the injector (5).

A mechanical fuel lockout switch for a dual fuel engine includes a mechanical fuel valve actuatable between a first position and a second position to selectively control fuel flow to the dual fuel engine from a first fuel source through a first fuel line and a second fuel source through a second fuel line. The mechanical fuel lockout switch may also include a fuel lockout apparatus coupled to the mechanical fuel valve. The mechanical fuel valve may be configured to allow communication between the first fuel source and the dual fuel engine and prevent communication between the second fuel source and the dual fuel engine while in the first position, and prevent communication between the first fuel source and the dual fuel engine while in the second position.

A computer-implemented method for controlling direct injection of hydrogen fuel into an engine cylinder of a vehicle from a hydrogen tank via an injector system. The method includes determining a present hydrogen pressure in the hydrogen tank; determining a present requested engine torque and speed; determining a target injection pressure for injecting hydrogen into the engine combustion chamber using a model the target injection pressure is the injection pressure that, according to the model, minimizes the mechanical work of the compressor, that provides an in-cylinder pressure sufficient for the engine to provide the requested engine torque and speed, that provides NOx emission below a predetermined maximum NOx emission level, and that reduces engine fuel consumption, and adjusting the injector pressure according to the determined target injection pressure.

A vehicle propulsion system includes a first pump having an inlet for receiving fuel from a fuel reservoir and an outlet for providing pressurized fuel to a fuel feed line at a first pressure, a fuel feed line pressure sensor, a second pump having an inlet for receiving fuel from the fuel feed line and an outlet for providing pressurized fuel to an engine fuel rail at a second pressure, the second pressure being higher than the first pressure, a fuel temperature sensor, and a controller controlling the first pump to reduce the pressure of the fuel in the fuel feed line and determining whether the pressure of the fuel in the fuel feed line has reached a vaporization pressure of a component in the fuel.

Embodiments of a gaseous or dual fuel electronic pressure regulation system (EPRS) for a multipoint fuel injection engine are described herein. Additionally, embodiments of a method for controlling the EPRS are provided. In particular, the EPRS employs an electronic pressure regulator (EPR) capable of accurately determining and controlling the mass flow of gaseous fuel into a fuel rail so as to avoid pressure droop and over- and under-pressurization of the gas admission valves (GAVs). By using the EPRS described above, mass flow is able to be distributed to the downstream manifold or engine cylinders very accurately, and the GAVs are able to be driven simultaneously in a pressure/pulse duration that is optimal for accurate and repeatable operation.

A supplemental fuel system includes a supplemental fuel tank, an electronic valve, a voltage sensor, and a controller. The supplemental fuel tank is configured to store a supplemental fuel configured to supplement a primary fuel used by an engine. The electronic valve is configured to be positioned between the supplemental fuel tank and an air supply system for the engine. The voltage sensor is configured to acquire voltage data from a power supply indicative of a voltage of the power supply. The power supply is configured to receive power from an alternator driven by the engine. The controller is configured to control the electronic valve such that the electronic valve is closed in response to the voltage being less than a voltage threshold indicating that the engine is not operating and open/openable in response to the voltage being greater than the voltage threshold indicating that the engine is operating.

A supplemental fuel system includes a fuel mixer having a nozzle and a stem. The nozzle is configured to be positioned within a conduit of an air supply system for an engine. The nozzle has a body defining a first inlet, an outlet, a passage extending from the first inlet to the outlet, and a second inlet positioned between the first inlet and the outlet. The body has a first cross-sectional dimension that is configured to be less than a second cross-sectional dimension of the conduit such that (i) a first portion of air flowing through the conduit flows through the passage and (ii) a second portion of the air flowing through the conduit flows around the nozzle. The stem has a first end that interfaces with the second inlet. The stem is configured to extend through a wall of the conduit.

An internal combustion engine assembly comprising a fuel reformer, a combustion chamber and a controller. The fuel reformer comprises a first channel and a second channel, a portion of the second channel being adjacent to a portion of the first channel to facilitate heat exchange between the first and second channels. The first channel comprises a catalyst selected to reform ammonia to hydrogen and nitrogen. The first channel is configured to receive ammonia, pass the ammonia over the catalyst and output a first mixture comprising ammonia, hydrogen and nitrogen. The composition of the first mixture depends on a first reformer temperature of the first channel. The combustion chamber is configured to receive the first mixture from the fuel reformer; to receive an oxidant; to combust the first mixture in the oxidant to produce heat and a first product; and to output the first product. The second channel of the fuel reformer is configured to receive the first product.

A method for determining failure of an electromechanically actuated gas shut off valve includes sensing and recording a gas fuel rail pressure and a boost pressure from an air intake manifold at a first time after the dual fuel engine has been started. The method includes opening the gas shut off valve at a second time, holding the gas shut off valve in its open state, and then closing the gas shut off valve after a predetermined interval at a third time. The method includes comparing an actual gas rail pressure decay rate to a threshold gas rail pressure decay rate for the predetermined interval, and determining failure of the gas shut off valve when the actual gas rail pressure decay rate is less than the threshold gas rail pressure decay rate. Upon determining failure of the gas shut off valve, the method also includes initiating a mitigating action.

Disclosed are a fluid control system and method for controlling delivery of two variable pressure fluids to maintain a pressure bias between the two fluids within an end use device. The system employs an actively controlled vent valve which can be integrated into a fluid control module in preferred embodiments and is actuated to an open position to decrease fluid pressure in a first fluid supply line when a determined pressure differential reversal exceeds a predetermined threshold pressure differential reversal. The disclosed system is particularly useful in a high pressure direct injection (HPDI) multi-fueled engine system where the first fluid is a gaseous fuel and the second fluid is a liquid fuel. The fluid control system and method of controlling it provide for improved control of venting along with protecting system components from high back pressure and cross contamination of fluids.