A method may comprise: positioning a pressure control valve (PCV) at an outlet of a fuel rail; positioning a volume control valve (VCV) at an inlet of a high pressure pump; and in response to an exhaust particulate matter (PM) level deviating from a target PM level, adjusting a fuel ratio of a first fuel and a second fuel delivered to an engine, and opening one of the PCV and the VCV. In this way, the fuel oxygen content may be adjusted to maintain a PM at or below a target level without a DPF over a broad range of engine designs and operating conditions, while maintaining fuel economy.

A dual-fuel injector to be arranged in a dual-fuel injection equipment of an internal combustion engine extends along a main axis from a top-head to a nozzle-tip. A first circuit conveys a first fuel to a first set of injection holes and a second circuit conveys a second fuel to a second set of injection holes.

An internal combustion engine has both a primary fuel system and a starting fuel intake assembly. The primary fuel system and the starting fuel intake assembly provide separate flow paths to a common chamber of the internal combustion engine. An external starting fuel source is fluidly connectable with the starting fuel intake assembly of the internal combustion engine, for instance when exposed to a low ambient temperature environment. The internal combustion engine is started while a starting fuel is flowing into a combustion chamber for the internal combustion engine. A primary fuel may also be flowing into the combustion chamber at this time. After the primary fuel is being consistently ignited in the combustion chamber, the flow of starting fuel to the combustion chamber may be terminated and the external starting fuel source may be fluidly disconnected from the starting fuel intake assembly of the internal combustion engine.

A multi-fuel engine includes an engine operable on a liquid fuel and a gaseous fuel. The multi-fuel engine also includes a liquid cutoff solenoid coupled to open and close a liquid fuel path to the engine, and a gaseous cutoff solenoid coupled to open and close a gaseous fuel source to the engine. A switch couples a power source to the liquid cutoff solenoid and the gaseous cutoff solenoid to switch between fuel sources on-the-fly during engine 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.

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.

A multi-fuel engine includes an engine operable on a liquid fuel and first and second gaseous fuels. The multi-fuel engine also includes a liquid cutoff solenoid selectively operable between open and closed positions to allow and inhibit a flow of the liquid fuel to the engine and at least one gaseous cutoff valve selectively operable between open and closed positions to allow and inhibit a flow of the first and second gaseous fuels to the engine. A jet block couples the first gaseous fuel source and the second gaseous fuel source to a carburetor connected to an intake of the engine, with the jet block being located downstream from the at least one gaseous cutoff valve. The jet block includes a first gaseous fuel jet to meter the first gaseous fuel to the carburetor and a second gaseous fuel jet to meter the second gaseous fuel to the carburetor.

A combination control assembly for dual fuel internal combustion engine comprises: a bracket (8) that is fixed on an engine shell (12); a micro switch (9) that is used to send signals; a female quick connector (7) is used to connect with the carburetor and a male quick connector (10) is used to connect with the female quick connector (7); a gas pipe (11) is used to connect with the male quick connector (10) and the other side, gaseous fuel; the bracket (8) is provided with the micro switch (9) and the female quick connector (7), the micro switch (9) is provided with a reed (91), and the male quick connector (10) is provided with a trigger tab (101). When the male quick connector (10) is connected to the female quick connector (7), the trigger tab (101) is against the reed (91). A knob component (6) is connected with the fuel valve (5) to control fuel flow in the fuel pipe (4), and the engine flameout is also controlled by the knob component (6).

An internal combustion engine includes an injector for injecting gaseous fuel and an inflow passage. The injector includes a nozzle hole configured to inject gaseous fuel, a nozzle valve configured to open and close the nozzle hole, and a seat surface on which the nozzle valve is seated. An inflow passage for conducting blow-by gas in a crankcase into the nozzle hole.