Methods and systems are providing for improving zero flow lubrication (ZFL) of a high pressure fuel pump coupled to direct fuel injectors via a direct injection fuel rail. A ZFL transfer function for the fuel pump is learned while fuel is at non-nominal fuel bulk modulus conditions and corrected for variations from a nominal fuel bulk modulus estimate. When zero flow lubrication of the pump is requested, the pump is operated with a duty cycle based on the learned transfer function and an instantaneous estimate of the fuel bulk modulus to compensate for differences in fuel condition from the nominal fuel bulk modulus estimate.

In a method and an arrangement for determining a fuel quality of a fuel for a combustion engine fuel is conveyed from a low pressure fuel tank to a high-pressure volume, and injected into at least one cylinder of the combustion engine. A control valve is provided for controlling directly or indirectly the amount of fuel injected into the at least one cylinder. An actual value of a timing signal of the control valve is compared to a reference value of the timing signal of the control valve and a fuel quality parameter is derived from a difference between the actual value and the reference value of the timing signal of the control valve and/or that a fuel quality parameter is derived from a gradient of the pressure increase during a build-up phase of the pressure in the high-pressure volume compared to a reference value of the gradient of the pressure increase in the high-pressure volume.

A dual fuel injector may be used to inject both gas and liquid fuel into a cylinder of a compression ignition engine. An injector body defines a first set of nozzle outlets, a second set of nozzle outlets, a first fuel inlet and a second fuel inlet. A dual solenoid actuator includes a first armature, a first coil, a second armature and a second coil that share a common centerline. The dual solenoid actuator has a non-injection configuration at which the first armature is at an un-energized position and the second armature is at an un-energized position. The dual solenoid actuator has a first fuel injection configuration at which the first fuel inlet is fluidly connected to the first set of nozzle outlets, the first armature is at an energized position and the second armature is at the un-energized position.

A dual fuel system includes a first pressurized fuel reservoir, a first fuel pump fluidly connected to the first pressurized fuel reservoir, a second pressurized fuel reservoir, and a second fuel pump including a pump outlet fluidly connected to the second pressurized fuel reservoir, a pumping chamber, an actuating fluid inlet fluidly connected to at least one of the first fuel pump or the first pressurized fuel reservoir, and at least one pumping element. The first fuel pump may have excess capacity, at least at times, so as to provide a pressurized first fuel for actuating the second fuel pump. The at least one pumping element may include an intensifier or de-intensifier plunger such that a flow rate of a second pressurized fuel from the second fuel pump is different than a flow rate of the first pressurized fuel from the first fuel pump as an actuating fluid for the second fuel pump. Related apparatus and methodology is also disclosed.

An internal combustion engine system is described herein. The system uses a mixer to mix two fuels to provide for a transition from using only one of the fuels to using only the other fuel as power demand changes. The output of the mixer is provided to the engine as a primary fuel. A controller opens and closes throttle valves to adjust the relative concentrations of a first fuel (e.g., diesel) and a second fuel (e.g., methanol) that enter the mixer. In some examples, rather than removing the desired performance and/or environmental benefits achieved by using the second fuel at power demand levels greater than the maximum achievable by only using the second fuel, the systems described herein allow the use of at least a portion of the second fuel in the primary fuel at those power demand levels.

The invention relates to a bi-fuel system (100) and a method for operating such a system, in which the following steps are performed by a control system (104) being part of the bi-fuel system (100): determining whether a relative amount of first fuel in the second fuel tank (2) is less than a predetermined minimum relative amount of first fuel in the second fuel tank (MIX %_min), and if said relative amount is less than MIX %_min, supplying first fuel via the fuel return line (18) to the second fuel tank (2), by temporarily opening the return line shut-off valve (12).

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.

A flow limiting valve, comprising a valve body adjustable between a closed position and an open position, wherein in the open position a flow channel for a conveying fluid is opened in the flow limiting valve and in the closed position the flow channel is closed, whereby the adjustment of the valve body is subject to conveying fluid pressure; wherein a control valve is integrated into a housing of the flow limiting valve through which the valve body is adjustable between open and closed positions, regardless of the conveying fluid.

A fuel system comprises a first fuel rail. A first fuel delivery system, including a first plurality of fuel injectors, is connected to the first fuel rail. The first plurality of fuel injectors injects an amount of fuel into a first portion of an engine. A second fuel rail has a second fuel delivery system, including a second plurality of fuel injectors. The second plurality of fuel injectors inject an amount of fuel into a second portion of the engine, distinct from the first portion. A controller, operatively connected to the first fuel delivery system and the second fuel delivery system selectively enables and disables operation of the first fuel delivery system and the second fuel delivery system based on one of a detected temperature and a detected pressure of fuel passing to corresponding ones of the first plurality of fuel injectors and the second plurality of fuel injectors.

A dual fuel system for an internal combustion engine includes a plurality of fuel injectors, a first fuel pump and a first fuel conduit extending to the plurality of fuel injectors, and a second fuel pump and a second fuel conduit extending to a fuel manifold fluidly connected to the plurality of fuel injectors. The dual fuel system also includes an overflow buffer arranged to receive a volume of the second fuel expelled from the second fuel conduit, and a valve movable from a closed position to an open position fluidly connecting the overflow buffer to the second fuel conduit. Expelling fuel from the second fuel conduit enables a rapid pressure drop in a supply pressure of the second fuel to hasten switchover of the internal combustion engine between fuel type.